[Fix] (SelfTest): stop optional-capability failures from declaring the whole backend unsupported, and log the POST report in chunks

fixed Asio include bug and added the ignored dir item .gradle

.github/workflows/apk.yml

@@ -209,7 +209,7 @@ jobs:
       - name: Load trace cases
         id: trace-cases
         run: |
-          echo "android=$(python3 tools/trace_replay/trace_cases.py --ci --format github-apk)" >> "$GITHUB_OUTPUT"
+          echo "android=$(python3 tools/trace_replay/trace_cases.py --ci --format github-apk-matrix)" >> "$GITHUB_OUTPUT"
           echo "names=$(python3 tools/trace_replay/trace_cases.py --ci --format names)" >> "$GITHUB_OUTPUT"
 
   trace-fixtures:
@@ -337,13 +337,7 @@ jobs:
     strategy:
       fail-fast: false
       max-parallel: 4
-      matrix:
-        backend:
-          - name: DirectGLES
-            gpu: software
-          - name: DirectVulkan
-            gpu: lavapipe
-        case: ${{ fromJSON(needs.trace-cases.outputs.android) }}
+      matrix: ${{ fromJSON(needs.trace-cases.outputs.android) }}
     steps:
       - name: Set Swap Space
         uses: pierotofy/set-swap-space@v1.0
@@ -426,6 +420,9 @@ jobs:
           MOBILEGL_USE_ANGLE: ${{ matrix.backend.name == 'DirectGLES' && '1' || '0' }}
           MOBILEGL_TRACE_ANGLE_VARIANT: ${{ matrix.case.name == 'minecraft-1.21.4-fabric-iris-bliss-in-world' && '90a62123d794' || 'ec889e6ea831' }}
           MOBILEGL_MAGMA_R11G11B10F_FALLBACK: ${{ matrix.backend.name == 'DirectVulkan' && '1' || '0' }}
+          MOBILEGL_FIX_ITERATIONRP_SUBGROUP_SCRATCH: ${{ matrix.backend.name == 'DirectVulkan' && matrix.case.name == 'minecraft-1.21.4-fabric-iris-iterationrp-in-world' && '1' || '0' }}
+          MOBILEGL_DERIVE_NUM_SUBGROUPS: ${{ matrix.backend.name == 'DirectVulkan' && matrix.case.name == 'minecraft-1.21.4-fabric-iris-iterationrp-in-world' && '1' || '0' }}
+          MOBILEGL_ITERATIONRP_FIX_BARRIER: ${{ matrix.backend.name == 'DirectVulkan' && matrix.case.name == 'minecraft-1.21.4-fabric-iris-iterationrp-in-world' && '1' || '0' }}
         run: |
           apk_file="android-retrace-apks/MobileGL-plugin-trace-release-${GITHUB_SHA}.apk"
           test -f "${apk_file}"

.github/workflows/test.yml

@@ -265,6 +265,9 @@ jobs:
         # crash stack without burning a CI round on an in-workflow debugger.
         env:
           MOBILEGL_ITEST_REQUIRE_GPU: "1"
+          MOBILEGL_FIX_ITERATIONRP_SUBGROUP_SCRATCH: "1"
+          MOBILEGL_DERIVE_NUM_SUBGROUPS: "1"
+          MOBILEGL_ITERATIONRP_FIX_BARRIER: "1"
         run: |
           ulimit -c unlimited
           sudo sysctl -w kernel.core_pattern='/tmp/core.%e.%p'
@@ -491,6 +494,7 @@ jobs:
       - benchmark
       - integration
     outputs:
+      matrix: ${{ steps.trace-cases.outputs.matrix }}
       names: ${{ steps.trace-cases.outputs.names }}
     steps:
       - name: Checkout repo
@@ -498,7 +502,9 @@ jobs:
 
       - name: Load trace cases
         id: trace-cases
-        run: echo "names=$(python3 tools/trace_replay/trace_cases.py --ci --format names)" >> "$GITHUB_OUTPUT"
+        run: |
+          echo "matrix=$(python3 tools/trace_replay/trace_cases.py --ci --format github-test-matrix)" >> "$GITHUB_OUTPUT"
+          echo "names=$(python3 tools/trace_replay/trace_cases.py --ci --format names)" >> "$GITHUB_OUTPUT"
 
   trace-fixtures:
     name: trace fixture (${{ matrix.case }})
@@ -577,11 +583,7 @@ jobs:
     strategy:
       fail-fast: false
       max-parallel: 4
-      matrix:
-        backend:
-          - DirectGLES
-          - DirectVulkan
-        case: ${{ fromJSON(needs.trace-cases.outputs.names) }}
+      matrix: ${{ fromJSON(needs.trace-cases.outputs.matrix) }}
 
     steps:
       - name: Set Swap Space
@@ -640,6 +642,12 @@ jobs:
           if [ '${{ matrix.backend }}' = 'DirectVulkan' ]; then
             export MOBILEGL_MAGMA_R11G11B10F_FALLBACK=1
           fi
+          if [ '${{ matrix.backend }}' = 'DirectVulkan' ] \
+             && [ '${{ matrix.case }}' = 'minecraft-1.21.4-fabric-iris-iterationrp-in-world' ]; then
+            export MOBILEGL_FIX_ITERATIONRP_SUBGROUP_SCRATCH=1
+            export MOBILEGL_DERIVE_NUM_SUBGROUPS=1
+            export MOBILEGL_ITERATIONRP_FIX_BARRIER=1
+          fi
           # The blended depth-write quirk auto-enables only on Qualcomm, which no CI
           # runner has, so force it on for the OIT case it exists to fix. ForceOn
           # bypasses only the vendor gate, so this exercises the real strip on

.gitignore

@@ -27,3 +27,4 @@ MobileGL/MG*/cmake-build*
 tools/trace_replay/work/
 __pycache__/
 *.py[cod]
+/.gradle

CMakeLists.txt

@@ -182,6 +182,7 @@ set(ENABLE_SPVREMAPPER         OFF CACHE BOOL "Enable SPVRemapper" FORCE)
 set(ENABLE_OPT                 ON  CACHE BOOL "Enable SPIRV-Tools opt usage in glslang" FORCE)
 set(BUILD_EXTERNAL             ON  CACHE BOOL "Build external deps in External/" FORCE)
 set(ENABLE_GLSLANG_INSTALL     OFF CACHE BOOL "Install glslang targets" FORCE)
+set(SPIRV_SKIP_EXECUTABLES     ON  CACHE BOOL "Skip building SPIRV-Tools executables" FORCE)
 
 set(SPIRV_CROSS_C_API          ON  CACHE BOOL "Enable C API" FORCE)
 set(SPIRV_CROSS_ENABLE_GLSL    ON  CACHE BOOL "Enable GLSL backend" FORCE)
@@ -269,6 +270,7 @@ set(SOURCE_FILES
     MobileGL/MG_Util/ShaderTranspiler/ShaderCompiler.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpvcSession.cpp
     MobileGL/MG_Util/ShaderTranspiler/ShaderSourceProcessor.cpp
+    MobileGL/MG_Util/ShaderTranspiler/TranslationCache.cpp
     MobileGL/MG_Util/ShaderTranspiler/glslang/TMglGlslIoResolver.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/FlattenInterfaceStructPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/EliminateFloatEqualsZeroPass.cpp
@@ -277,25 +279,40 @@ set(SOURCE_FILES
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/DecomposeWorkgroupVec3Pass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/DecoratePositionInvariantPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/DemoteFloat64Pass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/FlattenFloat64StorageBlockPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/LowerDrawParametersPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/LowerViewportIndexPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/PackDoubleVertexInputsPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/FlattenXfbInterfaceBlocksPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/UniquifyIoBlockNamesPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/SplitArrayVertexInputsPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/RebaseInstanceIndexPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/ZeroBaseVertexPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/DeriveNumSubgroupsPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/FixIterationRPBarrierPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/FixIterationRPSubgroupScratchPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/EmulateSubgroupsPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/NormalizeRectCoordinatesPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/Lower1DArrayImagesPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/Lower1DSampledImagesPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/BakeImageFormatsPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/WidenImageFormatsPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/ClampMultisampleFetchPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/PrivateToEntryLocalPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/StripUniformLocationsPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/StripUboMemberRelaxedPrecisionPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/StripNoPerspectivePass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/EmulateNoPerspectivePass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/LegalizeFragmentOutputIndexPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/LegalizeResourceArrayIndexPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/FlattenAtomicCounterBlockPass.cpp
 
     MobileGL/MG_Util/BackendLoaders/OpenGL/Loader.cpp
     MobileGL/MG_Util/BackendLoaders/Vulkan/Loader.cpp
 
+    MobileGL/MG_Util/SelfTest/DriverBugProbes.cpp
     MobileGL/MG_Util/SelfTest/DriverPost.cpp
+    MobileGL/MG_Util/SelfTest/DriverPostIterationRPWitness.cpp
 
     MobileGL/MG_Util/Texture/PixelStoreProcessor.cpp
     MobileGL/MG_Util/Texture/TextureFormatProcessor.cpp
@@ -379,6 +396,7 @@ set(SOURCE_FILES
     MobileGL/MG_State/GLState/TextureState/TextureState.cpp
     MobileGL/MG_State/GLState/ProgramState/ProgramObject.cpp
     MobileGL/MG_State/GLState/ProgramState/ProgramLinkTask.cpp
+    MobileGL/MG_State/GLState/ProgramState/ProgramTranslationCache.cpp
     MobileGL/MG_State/GLState/ProgramState/ProgramSpirvTask.cpp
     MobileGL/MG_State/GLState/ProgramState/ShaderCompileTask.cpp
     MobileGL/MG_State/GLState/ProgramState/ShaderObject.cpp
@@ -456,7 +474,7 @@ set(MOBILEGL_INCLUDE_DIR
         # Header-only submodule: no add_subdirectory, no link target. Only
         # MG_Util/Async/ShaderCompilePool.cpp includes it, and it stays behind that file's
         # pimpl so no consumer target needs this path.
-        ${CMAKE_SOURCE_DIR}/3rdparty/asio/asio/include
+        ${CMAKE_SOURCE_DIR}/3rdparty/asio/include
 )
 
 add_library(${CMAKE_PROJECT_NAME} SHARED
@@ -668,3 +686,10 @@ if (NOT ANDROID)
         add_subdirectory(tools/trace_replay)
     endif()
 endif()
+
+# The integration binary is also useful as a standalone adb-shell executable.
+# Android cannot use the desktop-only MobileGL_s target, so its CMake module
+# links libMobileGL.so and creates an AImageReader-backed window instead.
+if (ANDROID AND MOBILEGL_BUILD_INTEGRATION_TEST)
+    add_subdirectory(MobileGL/MG_IntegrationTest)
+endif()

MobileGL/Config.h

@@ -66,22 +66,53 @@ namespace MobileGL::MG_Config {
     //   - DISPLAY: X11 session variable, not MobileGL configuration.
     //   - MOBILEGL_LOG_FILE_PATH: log-file init runs before MG_ConfigLoader::Init
     //     (see MG_Util/Debug/Log.cpp).
-    //   - MOBILEGL_VALIDATE_SPIRV: test suites like SpirvPassTest exercise
-    //     ShaderCompiler without ever running MobileGL::Initialize(), and every
-    //     Initialize() re-runs MG_ConfigLoader::Init, which would clobber a
-    //     programmatic override stored here (see ShaderCompiler.cpp,
-    //     SpirvValidationEnabled).
     struct FeaturesTable {
         // MOBILEGL_DISABLE_TIMERQUERY: do not advertise or use GPU timer queries.
         Bool DisableTimerQuery = false;
+        // MOBILEGL_ENABLE_SPIRV_VALIDATION: validate generated and transformed SPIR-V.
+        // Disabled by default because validation is a diagnostics-only cost.
+        Bool EnableSpirvValidation = false;
         // MOBILEGL_USE_ANGLE: load ANGLE EGL/GLES libraries.
         Bool UseAngle = false;
 #if defined(MOBILEGL_TRACE_ANGLE_VARIANTS)
         // MOBILEGL_TRACE_ANGLE_VARIANT: signed trace-APK ANGLE build short hash.
         String TraceAngleVariant;
 #endif
-        // MOBILEGL_DISABLE_SUBGROUP: force-disable Vulkan shader subgroup support.
+        // MOBILEGL_DISABLE_SUBGROUP: force-disable Vulkan shader subgroup support,
+        // including the opt-in emulated compute path below.
         Bool DisableSubgroup = false;
+        // MOBILEGL_MAGMA_EMULATE_SUBGROUP: implement GL_KHR_shader_subgroup's compute
+        // stage on a 32-lane VIRTUAL subgroup lowered to workgroup-shared memory
+        // (ShaderTranspiler::EmulateSubgroupsPass). Strictly a last resort: it only ever
+        // engages when this flag is set AND the device has no native subgroup support at
+        // all - a device with real subgroup operations always uses them natively,
+        // whatever their width (the known iterationRP defect is patched by
+        // FixIterationRPSubgroupScratch below instead). Off by default.
+        Bool MagmaEmulateSubgroup = false;
+        // MOBILEGL_FIX_ITERATIONRP_SUBGROUP_SCRATCH: patch iterationRP's own bug - the
+        // pack declares `shared vec2 prefixSumCache[32]` for a 512-invocation exposure
+        // reduction and indexes it by gl_SubgroupID, so any device with sub-16-lane
+        // subgroups (8-lane lavapipe -> 64 subgroups) writes shared memory out of
+        // bounds. The pass grows that one array to what the device's topology needs and
+        // touches nothing else; it only rewrites modules positively matching the pack's
+        // reduction fingerprint (ShaderTranspiler::FixIterationRPSubgroupScratchPass),
+        // so every other shader passes through byte-identical - as does iterationRP
+        // itself on >= 16-lane devices. Auto is ON; ForceOff replays the pack's bug
+        // verbatim.
+        QuirkOverride FixIterationRPSubgroupScratch = QuirkOverride::Auto;
+        // MOBILEGL_ITERATIONRP_FIX_BARRIER: repair Program 203's missing workgroup
+        // rendezvous between its two reductions over prefixSumCache. Off by default and
+        // fingerprint-gated by FixIterationRPBarrierPass when enabled.
+        Bool IterationRPFixBarrier = false;
+        // MOBILEGL_DERIVE_NUM_SUBGROUPS: replace compute gl_NumSubgroups loads with
+        // ceil(workgroup invocations / gl_SubgroupSize) on the NATIVE subgroup path
+        // (ShaderTranspiler::DeriveNumSubgroupsPass). Auto is ON: GL requires
+        // gl_SubgroupID < gl_NumSubgroups, Adreno's builtin reports 1 while the same
+        // dispatch emits IDs 0..7, and the derived value is the one Vulkan guarantees
+        // whenever the pipeline can request REQUIRE_FULL_SUBGROUPS (which the renderer
+        // does whenever local_size_x is a multiple of the native width). ForceOff returns
+        // to the raw driver builtin.
+        QuirkOverride DeriveNumSubgroups = QuirkOverride::Auto;
         // MOBILEGL_ADVERTISE_FP64: add GL_ARB_gpu_shader_fp64 to the advertised extension
         // string. `double` in a shader always WORKS - it is narrowed to 32 bits before any
         // module reaches a backend (ShaderTranspiler::DemoteFloat64Pass) - but the extension
@@ -130,10 +161,6 @@ namespace MobileGL::MG_Config {
         // explicitly request a core profile via EGL_CONTEXT_OPENGL_PROFILE_MASK / a >=3.1
         // version request.
         Bool RelaxedSemantics = false;
-        // MOBILEGL_QUIRK_SUBGROUP_PREFIX_SCAN: overrides the shader-source quirk that
-        // rewrites the recognized workgroup prefix-scan template on Qualcomm devices with
-        // subgroups wider than 32 lanes (see ShaderSourceProcessor's quirk registry).
-        QuirkOverride SubgroupPrefixScanQuirk = QuirkOverride::Auto;
         // MOBILEGL_MAGMA_DISABLE_BLENDED_DEPTH_WRITE: overrides the DirectVulkan quirk that
         // strips depth writes from accumulation-blended pipelines (MIN/MAX or additive
         // ONE+ONE - the multi-pass depth-equality signature) on drivers without
@@ -176,6 +203,28 @@ namespace MobileGL::MG_Config {
         // immediately stay serial by their own construction). Off by default; never
         // advertise it.
         QuirkOverride AsyncOptimisticShaderStatus = QuirkOverride::Auto;
+        // MOBILEGL_SHADER_CACHE: the three-level, in-memory shader translation memo
+        // (MG_Util/ShaderTranspiler/TranslationCache.h). The levels follow the GL
+        // entry points - L1c memoizes one glCompileShader's PARSE VERDICT, L1 a
+        // linked program's whole front end, L2 DirectGLES's emitted ESSL. Auto is
+        // ON; ForceOff turns ALL THREE off and makes every translation run from
+        // scratch. The escape hatch exists because a wrong cache hit is a silently
+        // miscompiled shader: if a device ever renders differently with the cache
+        // on, one run with this falsy says so.
+        QuirkOverride ShaderTranslationCache = QuirkOverride::Auto;
+        // MOBILEGL_FORCE_VIEWPORT_ARRAY_EMULATION: DirectGLES' gl_ViewportIndex routing
+        // emulation - the builtin becomes a flat varying, the fragment stage gets a
+        // per-pass gate, and a routed draw is REPLAYED once per distinct viewport state
+        // with the real glViewport/glScissor/glDepthRangef set for it. Auto is ON, and
+        // it is ON even where the driver advertises GL_OES_viewport_array, because that
+        // extension only ever gave the SHADER a compilable name: MobileGL has never
+        // programmed a driver's INDEXED viewport state (SyncRenderState pushes index 0
+        // and nothing else), so on an extension-capable driver every index rasterized as
+        // index 0 exactly as it did without one. ForceOff returns to that behaviour -
+        // the pre-emulation path, extension passthrough where it exists and
+        // LowerViewportIndexPass' demote-to-a-plain-global where it does not - and is
+        // the negative control the emulation is measured against.
+        QuirkOverride ViewportArrayEmulation = QuirkOverride::Auto;
     };
     extern FeaturesTable Features;
 } // namespace MobileGL::MG_Config

MobileGL/ConfigLoader.cpp

@@ -162,11 +162,17 @@ namespace MobileGL::MG_ConfigLoader {
     inline void InitFeatures() {
         auto& features = MG_Config::Features;
         features.DisableTimerQuery = QueryEnvFlag("MOBILEGL_DISABLE_TIMERQUERY");
+        features.EnableSpirvValidation = QueryEnvFlag("MOBILEGL_ENABLE_SPIRV_VALIDATION");
         features.UseAngle = QueryEnvFlag("MOBILEGL_USE_ANGLE");
 #if defined(MOBILEGL_TRACE_ANGLE_VARIANTS)
         QueryEnvVariable("MOBILEGL_TRACE_ANGLE_VARIANT", features.TraceAngleVariant, "");
 #endif
         features.DisableSubgroup = QueryEnvFlag("MOBILEGL_DISABLE_SUBGROUP");
+        features.MagmaEmulateSubgroup = QueryEnvFlag("MOBILEGL_MAGMA_EMULATE_SUBGROUP");
+        features.FixIterationRPSubgroupScratch =
+            QueryEnvQuirkOverride("MOBILEGL_FIX_ITERATIONRP_SUBGROUP_SCRATCH");
+        features.IterationRPFixBarrier = QueryEnvFlag("MOBILEGL_ITERATIONRP_FIX_BARRIER");
+        features.DeriveNumSubgroups = QueryEnvQuirkOverride("MOBILEGL_DERIVE_NUM_SUBGROUPS");
         features.AdvertiseFp64 = QueryEnvFlag("MOBILEGL_ADVERTISE_FP64");
         features.MagmaR11G11B10FFallback = QueryEnvFlag("MOBILEGL_MAGMA_R11G11B10F_FALLBACK");
         features.MagmaFramesInFlight = QueryEnvUint32("MOBILEGL_MAGMA_FRAMESINFLIGHT", 3, 1, 64);
@@ -179,7 +185,6 @@ namespace MobileGL::MG_ConfigLoader {
         features.EsprytForceDepthStencilReadbackEmulation =
             QueryEnvFlag("MOBILEGL_ESPRYT_FORCE_DS_READBACK_EMULATION");
         features.RelaxedSemantics = QueryEnvFlag("MOBILEGL_RELAXED_SEMANTICS");
-        features.SubgroupPrefixScanQuirk = QueryEnvQuirkOverride("MOBILEGL_QUIRK_SUBGROUP_PREFIX_SCAN");
         features.MagmaDisableBlendedDepthWriteQuirk =
             QueryEnvQuirkOverride("MOBILEGL_MAGMA_DISABLE_BLENDED_DEPTH_WRITE");
         features.DisableRobustBufferAccess = QueryEnvFlag("MOBILEGL_DISABLE_ROBUST_BUFFER_ACCESS");
@@ -189,6 +194,9 @@ namespace MobileGL::MG_ConfigLoader {
         features.AsyncShaderCompileThreads = QueryEnvUint32("MOBILEGL_ASYNC_SHADER_COMPILE_THREADS", 0, 0, 64);
         features.AsyncOptimisticShaderStatus =
             QueryEnvQuirkOverride("MOBILEGL_ASYNC_OPTIMISTIC_SHADER_STATUS");
+        features.ShaderTranslationCache = QueryEnvQuirkOverride("MOBILEGL_SHADER_CACHE");
+        features.ViewportArrayEmulation =
+            QueryEnvQuirkOverride("MOBILEGL_FORCE_VIEWPORT_ARRAY_EMULATION");
     }
 
     inline void InitBackendType() {

MobileGL/Defines.h

@@ -52,11 +52,15 @@
 // that includes Defines.h without Log.h both tokens would silently evaluate to 0 in the
 // preprocessor conditional - enabling the assert in exactly the INFO-level builds it is
 // documented to be compiled out of. Log.h redefines them identically, which is legal.
+//
+// Severity order, ascending: DEBUG < INFO < WARN < ERROR < FATAL. MOBILEGL_LOG_ACTIVE_LEVEL
+// names the lowest severity compiled in, so the production default INFO keeps I/W/E/F and
+// drops only D. Any edit here must be mirrored in Log.h.
 #ifndef MOBILEGL_LOG_LEVEL_DEBUG
 #define MOBILEGL_LOG_LEVEL_DEBUG 0
-#define MOBILEGL_LOG_LEVEL_WARN 1
-#define MOBILEGL_LOG_LEVEL_ERROR 2
-#define MOBILEGL_LOG_LEVEL_INFO 3
+#define MOBILEGL_LOG_LEVEL_INFO 1
+#define MOBILEGL_LOG_LEVEL_WARN 2
+#define MOBILEGL_LOG_LEVEL_ERROR 3
 #define MOBILEGL_LOG_LEVEL_FATAL 4
 #endif
 
@@ -91,6 +95,12 @@
 #endif
 
 // =============================== Utils ================================ //
+// Asserts are live in exactly the builds where MGLOG_D is live, i.e. DEBUG builds only;
+// an INFO build (the production default) compiles them out. DEBUG is the lowest severity
+// in the ordering above, so "ACTIVE <= DEBUG" is true only for ACTIVE == DEBUG - the same
+// gate MGLOG_D uses in Log.h. That equivalence is what makes this gate survive the
+// 2026-08-13 renumbering unchanged; the contract is and stays
+// "INFO builds: asserts OFF; DEBUG builds: asserts ON".
 #if MOBILEGL_LOG_ACTIVE_LEVEL <= MOBILEGL_LOG_LEVEL_DEBUG
     #define MOBILEGL_ASSERT(condition, ...)                                                                                \
         do {                                                                                                               \

MobileGL/Init.cpp

@@ -15,8 +15,11 @@
 #include <MG_Impl/GLImpl/Texture/ProxyTexture.h>
 #include <MG_Impl/GLImpl/Framebuffer/GL_Framebuffer.h>
 #include <MG_Impl/GLImpl/Sync/GL_Sync.h>
+#include <MG_Impl/GLImpl/Query/GL_Query.h>
 #include <MG_Util/Async/ShaderCompilePool.h>
 #include <MG_Util/ShaderTranspiler/ShaderCompiler.h>
+#include <MG_State/GLState/ProgramState/ProgramTranslationCache.h>
+#include <MG_Util/ShaderTranspiler/TranslationCache.h>
 
 #include <atomic>
 #include <mutex>
@@ -51,6 +54,11 @@ namespace MobileGL {
             // before a re-initialized library could pair them with the wrong
             // backend's DeleteSync).
             MG_Impl::GLImpl::DestroyAllSyncObjects();
+            // Queries die with their contexts for the same reason, and their registry
+            // is the same shape of process-global map: drain it here too, while the
+            // function table can still pair each backend handle with the backend that
+            // minted it.
+            MG_Impl::GLImpl::DestroyAllQueryObjects();
             MG_Backend::pActiveBackendObject.reset();
             MG_State::pGLContext.reset();
             MG_State::pEGLContext.reset();
@@ -66,6 +74,14 @@ namespace MobileGL {
             // built-in symbol tables the prewarm latch stands for, so leaving it set would
             // make the next Initialize() skip a prewarm it genuinely needs.
             MG_Util::ShaderTranspiler::ShaderCompiler::ResetPrewarmLatch();
+            // The two-level translation memo. Nothing in it references a glslang object -
+            // both levels hold plain bytes - so this is RSS hygiene rather than a lifetime
+            // requirement, and it is safe either side of FinalizeProcess. Stats first: an
+            // fordebug build gets one line per level saying how the run went.
+            MG_Util::ShaderTranspiler::LogShaderTranslationCacheStats();
+            MG_Util::ShaderTranspiler::ClearShaderTranslationCaches();
+            MG_State::GLState::LogProgramTranslationCacheStats();
+            MG_State::GLState::ClearProgramTranslationCache();
             MG_Backend::gBackendFunctionsTable = {};
             g_isInitialized = false;
             if (logLifecycle) {

MobileGL/MG_Backend/BackendObject.h

@@ -14,6 +14,7 @@ namespace MobileGL {
     namespace MG_State::GLState {
         class FramebufferObject;
         class ITextureObject;
+        class RenderbufferObject;
     }
 
     enum class BackendType {
@@ -24,6 +25,19 @@ namespace MobileGL {
     };
 
     namespace MG_Backend {
+        // One endpoint of a glCopyImageSubData. GL 4.6 core 18.3.2 accepts GL_RENDERBUFFER
+        // alongside the ten whole-image texture targets, and a renderbuffer name lives in a
+        // namespace of its own - so an endpoint is a sum type, not an ITextureObject. At most
+        // one of the two pointers is set; neither is set when the name named nothing, which is
+        // the INVALID_VALUE the frontend validator reports.
+        struct CopyImageEndpoint {
+            SharedPtr<MG_State::GLState::ITextureObject> Texture;
+            SharedPtr<MG_State::GLState::RenderbufferObject> Renderbuffer;
+
+            Bool IsRenderbuffer() const { return Renderbuffer != nullptr; }
+            Bool Exists() const { return Texture != nullptr || Renderbuffer != nullptr; }
+        };
+
         enum class FormatCapability : Uint64 {
             Creatable = 1ull << 0,
 
@@ -160,9 +174,9 @@ namespace MobileGL {
                                    GLsizei height, GLint border);
             void (*CopyTexSubImage2D)(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y,
                                       GLsizei width, GLsizei height);
-            void (*CopyImageSubData)(const SharedPtr<MG_State::GLState::ITextureObject>& srcTexture,
+            void (*CopyImageSubData)(const CopyImageEndpoint& src,
                                      GLenum srcTarget, GLint srcLevel, GLint srcX, GLint srcY, GLint srcZ,
-                                     const SharedPtr<MG_State::GLState::ITextureObject>& dstTexture,
+                                     const CopyImageEndpoint& dst,
                                      GLenum dstTarget, GLint dstLevel, GLint dstX, GLint dstY, GLint dstZ,
                                      GLsizei srcWidth, GLsizei srcHeight, GLsizei srcDepth);
             void (*GenerateMipmap)(GLenum target);
@@ -236,6 +250,14 @@ namespace MobileGL {
             // (optional; null = frontend falls back to CPU accounting).
             BackendQueryHandle (*BeginXfbPrimitivesQuery)(Bool generated);
             void (*EndXfbPrimitivesQuery)(BackendQueryHandle query);
+            // Whether GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN should be answered from the
+            // frontend's own accounting wherever that accounting is exact - a capture with no
+            // geometry stage - instead of from the query above. Set by DirectGLES, whose result
+            // is whatever the ES driver's PRIMITIVES_WRITTEN counter says: Adreno reports twice
+            // the written count for a vertex-only capture that follows a large render pass,
+            // where the desktop-exact answer is the one the frontend already computed. Defaults
+            // to false, so a backend that never sets it keeps using its GPU result.
+            Bool PrefersCpuXfbPrimitiveAccounting = false;
             // Transform feedback capture spans, for backends whose own GL/ES driver
             // performs the capture (DirectGLES). Both optional; null means the backend
             // drives capture from its draw recording instead (DirectVulkan). End is
@@ -318,6 +340,22 @@ namespace MobileGL {
             Int MaxVertexAttribs = 16;
             Int MaxComputeShaderStorageBlocks = 8;
             Int MaxCombinedShaderStorageBlocks = 32;
+            // Per-stage GL_MAX_*_SHADER_STORAGE_BLOCKS. Zero is a legal answer for the four
+            // non-compute, non-fragment stages and these defaults are the spec minimums, not
+            // placeholders: GL 4.6 table 23.64 and ES 3.2 table 21.44 both set the minimum for
+            // vertex, tessellation control, tessellation evaluation and geometry at 0, and only
+            // fragment (8 in GL, 4 in ES) and compute are guaranteed to have any. Every real ARM
+            // GLES driver takes that allowance - a Mali-G925 reports 0 for all four - so a
+            // backend that cannot honour a graphics-stage storage block MUST report 0 here
+            // rather than a hopeful number. Advertising a non-zero count the driver will refuse
+            // does not make the block work; it only moves the failure from an honest
+            // "unsupported" at query time to a backend link error the frontend never surfaces,
+            // after which every draw with that program silently renders nothing.
+            Int MaxVertexShaderStorageBlocks = 0;
+            Int MaxTessControlShaderStorageBlocks = 0;
+            Int MaxTessEvaluationShaderStorageBlocks = 0;
+            Int MaxGeometryShaderStorageBlocks = 0;
+            Int MaxFragmentShaderStorageBlocks = 8;
             Int MaxComputeUniformBlocks = 12;
             Int MaxComputeWorkGroupInvocations = 128;
             Int MaxShaderStorageBufferBindings = 8;
@@ -334,8 +372,32 @@ namespace MobileGL {
             Int MaxComputeImageUniforms = 8;
             Int MaxDrawBuffers = 8;
             Int MaxColorAttachments = 8;
+            // GL_MAX_CLIP_DISTANCES. Zero is a legal answer here, not a placeholder, and a
+            // backend that cannot host a clip distance MUST report it: advertising eight the
+            // backend will refuse does not make gl_ClipDistance work, it only moves the failure
+            // from an honest "unsupported" at query time to a backend shader-compile error the
+            // frontend never surfaces, after which every draw with that program silently renders
+            // nothing. DirectGLES fills it from GL_EXT_clip_cull_distance, DirectVulkan from the
+            // shaderClipDistance device feature. The DEFAULT stays at the GL 4.3 core minimum
+            // because it describes the no-backend case (standalone shader compiles, unit tests),
+            // where there is no device to be honest about and BuildTBuiltInResource still has to
+            // hand glslang a workable gl_MaxClipDistances.
             Int MaxClipDistances = 8;
             Int MaxViewports = 16;
+            // GL_LAYER_PROVOKING_VERTEX / GL_VIEWPORT_INDEX_PROVOKING_VERTEX: which vertex of a
+            // primitive supplies gl_Layer and gl_ViewportIndex. GL 4.6 table 23.65 makes
+            // GL_UNDEFINED_VERTEX a legal answer for both, and it is the honest default - naming
+            // a convention is a statement about behaviour, so a backend that does not pin one
+            // must not claim it does. DirectGLES fills the layer one from the ES 3.2 query and
+            // the viewport one from GL_OES_viewport_array, and leaves UNDEFINED where the
+            // capability is absent: without the viewport array extension only viewport 0 is ever
+            // rasterized, so no convention selects anything. DirectVulkan keeps UNDEFINED for
+            // both - which vertex provokes is decided per pipeline by
+            // VulkanRenderer::SelectProvokingVertexMode out of VK_EXT_provoking_vertex,
+            // provokingVertexModePerPipeline and the topology, so no single convention is true
+            // of the backend.
+            GLenum LayerProvokingVertex = GL_UNDEFINED_VERTEX;
+            GLenum ViewportIndexProvokingVertex = GL_UNDEFINED_VERTEX;
             Int MaxViewportWidth = 16384;
             Int MaxViewportHeight = 16384;
             Float ViewportBoundsRangeMin = 0.0f;
@@ -383,12 +445,36 @@ namespace MobileGL {
                 const Uint32 bit = PerLayerFramebufferAttachmentBit(target);
                 return bit != 0 && (PerLayerFramebufferAttachmentTargets & bit) != 0;
             }
+            // Whether this backend can CONSUME a shader module that still declares 64-bit floats,
+            // i.e. whether `double` survives the transpile instead of being narrowed to `float`
+            // (ShaderTranspiler::DemoteFloat64Pass). Detected, never assumed:
+            //   * DirectVulkan sets it from VkPhysicalDeviceFeatures::shaderFloat64, the feature
+            //     VUID-VkShaderModuleCreateInfo-pCode-08740 requires before a module declaring
+            //     OpCapability Float64 may be created at all. lavapipe has it; Adreno and Mali
+            //     both report VK_FALSE, so no real mobile device does.
+            //   * DirectGLES can NEVER have it. GLSL ES has no 64-bit float type in any version
+            //     or extension, so SPIRV-Cross cannot emit one ("FP64 not supported in ES
+            //     profile") and the demotion there is mathematically mandatory, always.
+            // Defaults to false so a backend that never sets it - and the no-backend case, which
+            // is what standalone shader compiles and the unit tests run under - keeps the
+            // demotion, which is the behaviour that works everywhere.
+            Bool SupportsShaderFloat64 = false;
             // Whether glVertexAttribLFormat / glVertexArrayAttribLFormat can be honoured, i.e.
             // whether a 64-bit vertex attribute can actually reach a shader unconverted. Detected,
             // never assumed: DirectVulkan needs VkPhysicalDeviceFeatures::shaderFloat64 (the
             // attribute travels as its 32-bit word pair, so no VK_FORMAT_R64* is required, but the
             // bitcast result is Float64); DirectGLES can never have it, ESSL having no fp64 type at
             // all. Defaults to false so a backend that never sets it gets the conservative answer.
+            //
+            // INDEPENDENT of SupportsShaderFloat64, and it has to be: this flag decides a VkFormat
+            // from the VAO ATTRIBUTE alone, which does not know what type the shader declared, and
+            // glVertexAttribFormat(GL_DOUBLE) feeding a plain `in vec4` is both legal and common
+            // (KHR-GL43.vertex_attrib_binding.basic-input-case4/5, advanced-bindingUpdate). A
+            // backend with native fp64 that still cannot FETCH 64 bits keeps this false and relies
+            // on the per-MODULE rule in ShaderCompiler::SanitizeAndOptimizeBinary instead: a vertex
+            // module that declares a 64-bit float INPUT is demoted whole, so the two shader-side
+            // halves (PackDoubleVertexInputsPass and VertexInputStateFactory::ToVkVertexFormat)
+            // still see one consistent world.
             Bool SupportsFloat64VertexAttributes = false;
             SizeT MaxShaderStorageBlockSize = 128 * 1024 * 1024;
             Uint32 SubgroupSize = 0;

MobileGL/MG_Backend/DirectGLES/BackendObject_DirectGLES.cpp

@@ -8,6 +8,7 @@
 
 #include "BackendObject_DirectGLES.h"
 #include "MG_Backend/BackendObject.h"
+#include "MG_Backend/BackendObjects.h"
 #include <MG_Backend/DirectGLES/DirectGLES.h>
 #include <MG_Backend/DirectGLES/Managers.h>
 #include <MG_Backend/DirectGLES/Utils.h>
@@ -212,7 +213,10 @@ namespace MobileGL::MG_Backend::DirectGLES {
             if (options & PixelFormatNormalizeOptionBit::NoThreeChannelRenderTarget) {
                 reasons.push_back("no colour-renderable three-channel format on OpenGL ES");
             }
-            if (options & PixelFormatNormalizeOptionBit::NoSnorm16RenderTarget) {
+            // A format is either 8- or 16-bit signed normalized, so at most one of the two ever
+            // survives GetApplicablePixelFormatNormalizeOptions and the reason is not duplicated.
+            if ((options & PixelFormatNormalizeOptionBit::NoSnorm16RenderTarget) ||
+                (options & PixelFormatNormalizeOptionBit::NoSnorm8RenderTarget)) {
                 reasons.push_back("EXT_render_snorm not supported");
             }
 
@@ -406,9 +410,12 @@ namespace MobileGL::MG_Backend::DirectGLES {
             return complete;
         }
 
+        // `samples` only reaches the multisample targets; every other target ignores it. The
+        // descending sample walk (ProbeTextureSampleCounts) reuses this whole routine rather than
+        // repeating the gen/bind/completeness/delete dance.
         Bool ProbeTexture(const MG_External::GLESFunctionsTable& gl, TextureTarget target, GLenum internalFormat,
                           GLenum imageFormat, GLenum imageType, TextureInternalFormat logicalFormat,
-                          Bool* outRenderable) {
+                          Bool* outRenderable, Int samples = 1) {
             if (!IsGLESProbeTextureTarget(target) || !gl.glGenTextures || !gl.glBindTexture || !gl.glDeleteTextures) {
                 return false;
             }
@@ -428,10 +435,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
 
             const Bool isMultisample = IsGLESProbeMultisampleTarget(target);
             if (isMultisample) {
+                const auto probeSamples = static_cast<GLsizei>(std::max(samples, 1));
                 if (target == TextureTarget::Texture2DMultisample && gl.glTexStorage2DMultisample) {
-                    gl.glTexStorage2DMultisample(glTarget, 1, internalFormat, 1, 1, GL_TRUE);
+                    gl.glTexStorage2DMultisample(glTarget, probeSamples, internalFormat, 1, 1, GL_TRUE);
                 } else if (target == TextureTarget::Texture2DMultisampleArray && gl.glTexStorage3DMultisample) {
-                    gl.glTexStorage3DMultisample(glTarget, 1, internalFormat, 1, 1, 1, GL_TRUE);
+                    gl.glTexStorage3DMultisample(glTarget, probeSamples, internalFormat, 1, 1, 1, GL_TRUE);
                 } else {
                     gl.glBindTexture(glTarget, static_cast<GLuint>(previousBinding));
                     gl.glDeleteTextures(1, &texture);
@@ -527,6 +535,29 @@ namespace MobileGL::MG_Backend::DirectGLES {
             return sampleCounts;
         }
 
+        // The multisample TEXTURE twin of ProbeRenderbufferSampleCounts. It used to be a
+        // hardcoded {1}, which made glGetInternalformativ(GL_SAMPLES) claim a one-sample maximum
+        // for every format on the multisample targets even where glTexImage2DMultisample happily
+        // accepts four - GL 4.6 core 8.8 makes that query the definition of the maximum, so the
+        // two answers cannot both be right. Completeness is required at every count, exactly as
+        // the renderbuffer walk requires it; the caller only reaches here once the one-sample
+        // probe has already succeeded, so 1 terminates the list without being re-probed.
+        Vector<Int> ProbeTextureSampleCounts(const MG_External::GLESFunctionsTable& gl, TextureTarget target,
+                                             GLenum internalFormat, GLenum imageFormat, GLenum imageType,
+                                             TextureInternalFormat logicalFormat, Int maxSamples) {
+            Vector<Int> sampleCounts;
+            for (Int samples = std::max(maxSamples, 1); samples > 1; samples >>= 1) {
+                Bool renderable = false;
+                const Bool created = ProbeTexture(gl, target, internalFormat, imageFormat, imageType, logicalFormat,
+                                                  &renderable, samples);
+                if (created && renderable) {
+                    sampleCounts.push_back(samples);
+                }
+            }
+            sampleCounts.push_back(1);
+            return sampleCounts;
+        }
+
         void PopulateFormatCapabilitiesImpl(const MG_External::GLESFunctionsTable& gl,
                                             const MG_External::GLESCapabilities& capabilities,
                                             FormatCapabilityCache& cache) {
@@ -627,7 +658,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
                             AddFullFormatCaps(cache, targetIndex, formatIndex,
                                               BuildTextureCapsFromProbe(logicalFormat, target, nativeRenderable));
                             if (IsGLESProbeMultisampleTarget(target)) {
-                                cache.SampleCounts[targetIndex][formatIndex] = {1};
+                                const Int maxSamples =
+                                    GetGLESFormatMaxSamples(capabilities, logicalFormat, nativeInfo.ImageFormat);
+                                cache.SampleCounts[targetIndex][formatIndex] = ProbeTextureSampleCounts(
+                                    gl, probeTarget, nativeInfo.InternalFormat, nativeInfo.ImageFormat,
+                                    nativeInfo.ImageType, logicalFormat, maxSamples);
                             }
                         }
                         shouldProbeFallback = !nativeCreated || !nativeRenderable;
@@ -645,7 +680,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
                                 LogGLESFormatCaveat(logicalFormat, targetIndex, fallbackInfo);
                             }
                             if (IsGLESProbeMultisampleTarget(target)) {
-                                cache.SampleCounts[targetIndex][formatIndex] = {1};
+                                const Int maxSamples =
+                                    GetGLESFormatMaxSamples(capabilities, logicalFormat, fallbackInfo.ImageFormat);
+                                cache.SampleCounts[targetIndex][formatIndex] = ProbeTextureSampleCounts(
+                                    gl, probeTarget, fallbackInfo.InternalFormat, fallbackInfo.ImageFormat,
+                                    fallbackInfo.ImageType, logicalFormat, maxSamples);
                             }
                         }
                     }
@@ -712,9 +751,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
                     {
                         .TargetGLVersion = {4, 0, 0},   // GL target version
                         .TargetGLSLVersion = {4, 6, 0}, // Target Shading Language Version
-                        // Baseline advertisement (no timer queries / anisotropy yet); reconciled
-                        // once the ES capabilities exist, see UpdateAdvertisedCapabilityExtensions.
-                        .Extensions = BuildAdvertisedExtensions(false, false),
+                        // Baseline advertisement (no runtime capabilities yet); reconciled once
+                        // the ES capabilities exist, see UpdateAdvertisedCapabilityExtensions.
+                        .Extensions = BuildAdvertisedExtensions(false, false, false, false),
                         .IsCompatibilityProfile = false // Is Compatibility Profile
                     },
                 .StaticBackendCapability = {.AllowVSOnlyPrograms = false} // Backend Capability
@@ -734,9 +773,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // thread can only observe the extension string after the
         // advertisement for its context has settled; rebuilding the whole
         // list keeps the re-run after a context recreation idempotent.
-        void UpdateAdvertisedCapabilityExtensions(Bool anisotropicFilteringSupported) {
-            MutableRendererInfo().RendererGLInfo.Extensions =
-                BuildAdvertisedExtensions(AreTimerQueriesSupported(), anisotropicFilteringSupported);
+        void UpdateAdvertisedCapabilityExtensions(const MG_External::GLESCapabilities& capabilities) {
+            MutableRendererInfo().RendererGLInfo.Extensions = BuildAdvertisedExtensions(
+                AreTimerQueriesSupported(), capabilities.SupportsTextureFilterAnisotropy,
+                capabilities.SupportsDrawIndirect,
+                capabilities.SupportsDrawIndirect && capabilities.SupportsBaseInstance);
         }
     } // namespace
 
@@ -745,6 +786,29 @@ namespace MobileGL::MG_Backend::DirectGLES {
         PopulateFormatCapabilitiesImpl(gl, capabilities, cache);
     }
 
+    Int ClampSamplesToBackendSupport(SizeT targetIndex, TextureInternalFormat logicalFormat, GLenum imageFormat,
+                                     Int samples) {
+        if (samples <= 1) {
+            return samples;
+        }
+
+        Int maxSamples = 0;
+        const SizeT formatIndex = static_cast<SizeT>(logicalFormat);
+        if (pActiveBackendObject && targetIndex < kFormatCapabilityTargetCount &&
+            formatIndex < kFormatCapabilityFormatCount) {
+            // Descending, so the head is the largest count this device actually allocated.
+            const Vector<Int>& probedCounts =
+                pActiveBackendObject->GetFormatCapabilities().SampleCounts[targetIndex][formatIndex];
+            if (!probedCounts.empty()) {
+                maxSamples = probedCounts.front();
+            }
+        }
+        if (maxSamples <= 0) {
+            maxSamples = GetGLESFormatMaxSamples(g_GLESCapabilities, logicalFormat, imageFormat);
+        }
+        return std::min(samples, std::max(maxSamples, 1));
+    }
+
     BackendObject_DirectGLES::~BackendObject_DirectGLES() {
         DestroyEGLContext();
     }
@@ -779,11 +843,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
             return false;
         }
         DirectGLES::SetGLESCapabilities(m_GLESCapabilities);
-        // Now that g_GLESCapabilities knows about GL_EXT_disjoint_timer_query and
-        // GL_EXT_texture_filter_anisotropic, reconcile the advertisement (see the comment on
-        // UpdateAdvertisedCapabilityExtensions for why it cannot happen when the extension
-        // list is first built).
-        UpdateAdvertisedCapabilityExtensions(m_GLESCapabilities.SupportsTextureFilterAnisotropy);
+        // Now that g_GLESCapabilities knows the host extensions, entry points, and ES version,
+        // reconcile every runtime-gated advertisement (see the comment on
+        // UpdateAdvertisedCapabilityExtensions for why this cannot happen when the list is first
+        // built).
+        UpdateAdvertisedCapabilityExtensions(m_GLESCapabilities);
         UpdateDynamicBackendParameters();
         PopulateFormatCapabilities(m_GLESFunctions, m_GLESCapabilities, MutableFormatCapabilities());
         PrintFormatCapabilities(GetFormatCapabilities());
@@ -924,11 +988,13 @@ namespace MobileGL::MG_Backend::DirectGLES {
         return MutableRendererInfo();
     }
 
-    Vector<GLExtension> BuildAdvertisedExtensions(Bool timerQueriesSupported, Bool anisotropicFilteringSupported) {
+    Vector<GLExtension> BuildAdvertisedExtensions(Bool timerQueriesSupported, Bool anisotropicFilteringSupported,
+                                                  Bool drawIndirectSupported,
+                                                  Bool nonZeroIndirectBaseInstanceSupported) {
         Vector<GLExtension> extensions = {
             V_OpenGL30, V_OpenGL31, V_OpenGL32, V_OpenGL33, V_OpenGL40, E_GL_ARB_draw_buffers_blend,
             E_GL_ARB_compute_shader, E_GL_ARB_shader_storage_buffer_object, E_GL_ARB_shader_image_load_store,
-            E_GL_ARB_program_interface_query, E_GL_ARB_framebuffer_object, E_GL_EXT_framebuffer_object,
+            E_GL_ARB_clear_buffer_object, E_GL_ARB_program_interface_query, E_GL_ARB_framebuffer_object, E_GL_EXT_framebuffer_object,
             E_GL_ARB_depth_texture, E_GL_ARB_buffer_storage, E_GL_ARB_texture_storage,
             E_GL_ARB_texture_storage_multisample, E_GL_ARB_clear_texture, E_GL_ARB_direct_state_access,
             E_GL_ARB_multi_draw_indirect, E_GL_ARB_indirect_parameters, E_GL_ARB_shader_draw_parameters,
@@ -955,6 +1021,19 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // extension explicitly permits. It is also the only thing that
             // exposes glProgramParameteri before GL 4.1.
             E_GL_ARB_get_program_binary};
+        // Minecraft 26.3 checks this prerequisite before it even considers
+        // GL_ARB_multi_draw_indirect. ES 3.1 supplies both single-draw entry points; the loader
+        // folds the version and pointer checks into SupportsDrawIndirect.
+        if (drawIndirectSupported) {
+            extensions.push_back(E_GL_ARB_draw_indirect);
+        }
+        // ARB_base_instance also defines the last word of an indirect command. Direct calls are
+        // emulated on every Espryt device, but without host GL_EXT_base_instance a native indirect
+        // draw cannot shift divisor attributes by a GPU-authored non-zero value, so do not promise
+        // that incomplete case.
+        if (drawIndirectSupported && nonZeroIndirectBaseInstanceSupported) {
+            extensions.push_back(E_GL_ARB_base_instance);
+        }
         // GL_KHR_parallel_shader_compile is MobileGL's own capability, not the host ES
         // driver's: the compiler threads are MobileGL's, and glCompileShader/glLinkProgram
         // are serviced entirely inside the frontend. Whether the device driver advertises
@@ -1090,6 +1169,12 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // geometry shader's amplification.
             funcsTable.GL.BeginXfbPrimitivesQuery = BeginXfbPrimitivesQuery;
             funcsTable.GL.EndXfbPrimitivesQuery = EndXfbPrimitivesQuery;
+            // ...but where it CAN see the whole capture - no geometry stage - the frontend's
+            // own count is the desktop-exact one and the ES driver's is only as good as the
+            // vendor made it (Adreno doubles PRIMITIVES_WRITTEN for a vertex-only capture that
+            // follows a large render pass). The query above stays installed: it is still what
+            // answers an amplifying span, and PRIMITIVES_GENERATED always.
+            funcsTable.GL.PrefersCpuXfbPrimitiveAccounting = true;
             funcsTable.GL.IsQueryResultAvailable = IsQueryResultAvailable;
             funcsTable.GL.GetQueryResult64 = GetQueryResult64;
             funcsTable.GL.DeleteBackendQuery = DeleteBackendQuery;
@@ -1169,9 +1254,31 @@ namespace MobileGL::MG_Backend::DirectGLES {
                      static_cast<Int>(MG_State::GLState::VertexArrayObject::MAX_VERTEX_ATTRIBS));
         m_dynamicParameters.MaxComputeShaderStorageBlocks = m_GLESCapabilities.MaxComputeShaderStorageBlocks;
         m_dynamicParameters.MaxCombinedShaderStorageBlocks = m_GLESCapabilities.MaxCombinedShaderStorageBlocks;
+        // Per-stage storage-block counts, forwarded from the host driver rather than invented.
+        // A stage the driver cannot serve reports 0, which is a legal answer everywhere these
+        // limits appear (GL 4.6 table 23.64, ES 3.2 table 21.44 - the minimum is 0 for every
+        // graphics stage except fragment) and is the only answer that lets an application take
+        // its own fallback instead of building a program the driver will refuse to link. The
+        // stage limit cannot exceed the combined limit or the number of binding points there
+        // are to bind buffers to, so clamp to both.
+        const auto clampStageStorageBlocks = [this](Int stageLimit) {
+            return std::min({std::max(stageLimit, 0), std::max(m_dynamicParameters.MaxCombinedShaderStorageBlocks, 0),
+                             std::max(m_dynamicParameters.MaxShaderStorageBufferBindings, 0)});
+        };
+        m_dynamicParameters.MaxShaderStorageBufferBindings = m_GLESCapabilities.MaxShaderStorageBufferBindings;
+        m_dynamicParameters.MaxVertexShaderStorageBlocks =
+            clampStageStorageBlocks(m_GLESCapabilities.MaxVertexShaderStorageBlocks);
+        m_dynamicParameters.MaxTessControlShaderStorageBlocks =
+            clampStageStorageBlocks(m_GLESCapabilities.MaxTessControlShaderStorageBlocks);
+        m_dynamicParameters.MaxTessEvaluationShaderStorageBlocks =
+            clampStageStorageBlocks(m_GLESCapabilities.MaxTessEvaluationShaderStorageBlocks);
+        m_dynamicParameters.MaxGeometryShaderStorageBlocks =
+            clampStageStorageBlocks(m_GLESCapabilities.MaxGeometryShaderStorageBlocks);
+        m_dynamicParameters.MaxFragmentShaderStorageBlocks =
+            clampStageStorageBlocks(m_GLESCapabilities.MaxFragmentShaderStorageBlocks);
         m_dynamicParameters.MaxComputeUniformBlocks = m_GLESCapabilities.MaxComputeUniformBlocks;
         m_dynamicParameters.MaxComputeWorkGroupInvocations = m_GLESCapabilities.MaxComputeWorkGroupInvocations;
-        m_dynamicParameters.MaxShaderStorageBufferBindings = m_GLESCapabilities.MaxShaderStorageBufferBindings;
+        // (MaxShaderStorageBufferBindings is assigned above, before the per-stage clamp reads it.)
         // This is the number glGetIntegerv(GL_MAX_TEXTURE_BUFFER_SIZE) hands the application, and
         // on a host without buffer textures it is knowingly a floor MobileGL cannot honour rather
         // than a driver answer (m_GLESCapabilities.MaxTextureBufferSizeIsDriverReported says
@@ -1224,14 +1331,26 @@ namespace MobileGL::MG_Backend::DirectGLES {
                     DynParams::PerLayerFramebufferAttachmentBit(TextureTarget::TextureCubeMapArray);
             }
         }
-        // Not a driver question and never will be: OpenGL ES has no double-precision vertex format
-        // and ESSL has no fp64 type to consume one with, so a 64-bit vertex attribute has nowhere to
-        // land on this backend regardless of what the driver underneath happens to support.
+        // Not a driver question and never will be: GLSL ES has no 64-bit float type in ANY version
+        // or extension, so SPIRV-Cross cannot emit one ("FP64 not supported in ES profile") and a
+        // module that still declared Float64 would never reach the driver at all. The demotion is
+        // mathematically mandatory here, on every device, forever - which is why this stays false
+        // regardless of what the driver underneath happens to support.
+        m_dynamicParameters.SupportsShaderFloat64 = false;
+        // Follows the line above, and must: OpenGL ES has no double-precision vertex format and no
+        // fp64 type to consume one with, so a 64-bit vertex attribute has nowhere to land here.
         m_dynamicParameters.SupportsFloat64VertexAttributes = false;
         m_dynamicParameters.MaxDrawBuffers = m_GLESCapabilities.MaxDrawBuffers;
         m_dynamicParameters.MaxColorAttachments = m_GLESCapabilities.MaxColorAttachments;
         m_dynamicParameters.MaxClipDistances = m_GLESCapabilities.MaxClipDistances;
         m_dynamicParameters.MaxViewports = m_GLESCapabilities.MaxViewports;
+        // Whatever the driver said about which vertex supplies gl_Layer, and GL_UNDEFINED_VERTEX
+        // for gl_ViewportIndex on every driver without GL_OES_viewport_array - which is both test
+        // devices. That is not a shortfall being hidden: without the extension only viewport 0 is
+        // ever rasterized, so no vertex "selects" a viewport index and naming a convention would
+        // describe behaviour this backend does not implement.
+        m_dynamicParameters.LayerProvokingVertex = m_GLESCapabilities.LayerProvokingVertex;
+        m_dynamicParameters.ViewportIndexProvokingVertex = m_GLESCapabilities.ViewportIndexProvokingVertex;
         m_dynamicParameters.MaxViewportWidth = m_GLESCapabilities.MaxViewportWidth;
         m_dynamicParameters.MaxViewportHeight = m_GLESCapabilities.MaxViewportHeight;
         m_dynamicParameters.ViewportBoundsRangeMin = m_GLESCapabilities.ViewportBoundsRangeMin;

MobileGL/MG_Backend/DirectGLES/BackendObject_DirectGLES.h

@@ -18,6 +18,16 @@ namespace MobileGL::MG_Backend::DirectGLES {
                                     const MG_External::GLESCapabilities& capabilities,
                                     FormatCapabilityCache& cache);
 
+    // Clamps a requested sample count down to what the ES driver can really deliver for this
+    // format on this format-capability target: the probed per-format list when there is one, the
+    // driver's per-class GL_MAX_*_SAMPLES otherwise. The frontend deliberately validates against
+    // the count MobileGL advertises instead (GL_Getter's GetAdvertisedMaxSamples), which on a
+    // driver reporting GL_MAX_INTEGER_SAMPLES 1 is higher than the driver accepts, so every ES
+    // allocation call has to come through here. The shadow state keeps the requested count, so
+    // GL_TEXTURE_SAMPLES and framebuffer completeness still answer what the application asked for.
+    Int ClampSamplesToBackendSupport(SizeT targetIndex, TextureInternalFormat logicalFormat, GLenum imageFormat,
+                                     Int samples);
+
     class BackendObject_DirectGLES : public BackendObject {
     public:
         ~BackendObject_DirectGLES() override;
@@ -67,9 +77,12 @@ namespace MobileGL::MG_Backend::DirectGLES {
     const RendererInfo& GetRendererIdentity();
 
     // The full OpenGL extension list Espryt advertises (glGetString(GL_EXTENSIONS))
-    // for a device whose timer queries / anisotropic filtering are (or are not) usable.
+    // for a device whose timer queries / anisotropic filtering / native indirect draws /
+    // non-zero indirect baseInstance semantics are (or are not) usable.
     // The MOBILEGL_DISABLE_TIMERQUERY escape hatch is applied inside.
-    Vector<GLExtension> BuildAdvertisedExtensions(Bool timerQueriesSupported, Bool anisotropicFilteringSupported);
+    Vector<GLExtension> BuildAdvertisedExtensions(Bool timerQueriesSupported, Bool anisotropicFilteringSupported,
+                                                  Bool drawIndirectSupported,
+                                                  Bool nonZeroIndirectBaseInstanceSupported);
 
     // Format: <OpenGL ES Renderer>, OpenGL ES <Major>.<Minor> — the exact string an
     // initialized backend returns from GetBackendAPIVersionString (and that ends up

MobileGL/MG_Backend/DirectGLES/DirectGLES.h

@@ -76,9 +76,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
                         GLsizei height, GLint border);
     void CopyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width,
                            GLsizei height);
-    void CopyImageSubData(const SharedPtr<MG_State::GLState::ITextureObject>& srcTexture,
+    void CopyImageSubData(const CopyImageEndpoint& src,
                           GLenum srcTarget, GLint srcLevel, GLint srcX, GLint srcY, GLint srcZ,
-                          const SharedPtr<MG_State::GLState::ITextureObject>& dstTexture,
+                          const CopyImageEndpoint& dst,
                           GLenum dstTarget, GLint dstLevel, GLint dstX, GLint dstY, GLint dstZ,
                           GLsizei srcWidth, GLsizei srcHeight, GLsizei srcDepth);
     void GenerateMipmap(GLenum target);

MobileGL/MG_Backend/DirectGLES/Managers.h

@@ -21,6 +21,29 @@ namespace MobileGL::MG_Backend::DirectGLES {
     String EmulateBaseInstanceInVertexShader(String source, GLenum shaderType);
     String PromoteDrawParameterGlobalsToUniforms(String source, GLenum shaderType);
 
+    // The ESSL half of the gl_ViewportIndex routing emulation, in the order a program's stages
+    // meet it. Both are pure String -> String rewrites over what SPIRV-Cross emitted once
+    // LowerViewportIndexPass has demoted the builtin to the plain global `mg_ViewportIndex`.
+    //
+    // The producing stage's global becomes an ordinary flat varying; true when there was one to
+    // promote, which is also the answer to "does this program route viewports at all".
+    Bool PromoteViewportIndexGlobalToVarying(String& source);
+    // The fragment stage grows a matching flat input, the mg_ViewportPassMask uniform the draw
+    // path writes, and a wrapper entry point that discards every fragment whose primitive routed
+    // to an index the current replay pass is not drawing. False when the stage has no entry point
+    // to wrap, which leaves the program renderable but unrouted.
+    Bool InjectViewportIndexPassGate(String& source);
+
+    // Whether a vertex shader may declare a storage block at all, given what the host driver
+    // reports for GL_MAX_VERTEX_SHADER_STORAGE_BLOCKS. Pure, and separated from the capability
+    // global purely so the decision can be tested without one.
+    //
+    // The indirect half of the gl_BaseInstance lowering in PromoteDrawParameterGlobalsToUniforms
+    // is the only thing that needs this, and it needs exactly one block. A driver reporting 0 is
+    // conformant - the minimum is 0 in GL 4.6 table 23.64 and ES 3.2 table 21.44 - and ARM's
+    // GLES driver does report 0, so this is a live path, not a defensive one.
+    Bool VertexStageStorageBlockUsable(Int maxVertexShaderStorageBlocks);
+
     // True once the process has entered exit(): past that point the EGL library and
     // the driver may already be unloaded, so a backend twin's destructor must not
     // call into g_GLESFuncs (the observed crash is a jump through an unmapped driver
@@ -103,6 +126,58 @@ namespace MobileGL::MG_Backend::DirectGLES {
     // link.
     Bool CurrentProgramMayNeedPerSubDrawBuiltins(Bool batchCarriesBaseVertices);
 
+    // ---- gl_ViewportIndex routing emulation, draw half ---------------------------------------
+    //
+    // GLES has ONE viewport, ONE scissor rectangle and ONE depth range; GL 4.1 has sixteen of
+    // each, selected per primitive by gl_ViewportIndex. There is no ES entry point to program the
+    // other fifteen with (GL_OES_viewport_array exists but Adreno 830 does not have it, verified
+    // three ways), so the only way to rasterize a primitive against index i's rectangle is to
+    // make index i's rectangle THE viewport for the duration of a draw - which means issuing the
+    // draw once per distinct viewport state and letting the fragment stage throw away the
+    // primitives that belong to the other indices (the gate Managers.cpp injects).
+    //
+    // Indices whose whole state tuple (viewport rectangle, scissor rectangle, scissor-test enable,
+    // depth range) is identical share ONE pass, so the overwhelmingly common case - every index
+    // still holding what glViewport/glScissor/glDepthRange broadcast to all sixteen - collapses
+    // to a single pass with an all-ones gate mask, i.e. one draw and no behaviour change at all.
+    //
+    // Whether emulation runs. Off only under MOBILEGL_FORCE_VIEWPORT_ARRAY_EMULATION falsy, which
+    // restores the pre-emulation path as a negative control.
+    Bool ViewportArrayEmulationEnabled();
+    // Whether ANY program built in this process has come out with a viewport gate. Sticky once
+    // true; it exists so that BeginViewportRoutingPasses - which runs on every draw of every
+    // workload - can answer with one static load in the case that matters, which is every
+    // application that has never heard of gl_ViewportIndex.
+    extern Bool g_anyProgramRoutesViewportIndex;
+    // Number of times the current draw has to be issued. Always >= 1, and exactly 1 - with no
+    // state touched - whenever the current program does not route viewports, whenever every
+    // configured index shares one state, and whenever replaying would multiply a side effect the
+    // fragment gate cannot undo (transform feedback, rasterizer discard). Also seeds the pass
+    // mask uniform for that single-pass case, so a gated fragment shader never runs against the
+    // zero every GLSL uniform starts at - which would discard the whole draw.
+    Uint BeginViewportRoutingPasses();
+    // Push pass `pass`'s viewport / scissor / scissor-test / depth range onto the ES context and
+    // set the gate mask to the indices it serves. Only called when the count above exceeds 1.
+    void ApplyViewportRoutingPass(Uint pass);
+    // Restore the gate mask and mark the render-state shadow dirty, so the next ordinary draw
+    // re-pushes index 0's state. Takes the count so it can do nothing at all in the common case.
+    void EndViewportRoutingPasses(Uint passCount);
+
+    // Issue one draw, replayed once per viewport-routing pass. Every application-visible draw
+    // entry point wraps its native glDraw* call in this; the internal blit and clear helpers
+    // deliberately do not, because they bind their own programs, which never route.
+    template <typename IssueDraw>
+    inline void ForEachViewportRoutingPass(IssueDraw&& issue) {
+        const Uint passCount = BeginViewportRoutingPasses();
+        for (Uint pass = 0; pass < passCount; ++pass) {
+            if (passCount > 1) {
+                ApplyViewportRoutingPass(pass);
+            }
+            issue();
+        }
+        EndViewportRoutingPasses(passCount);
+    }
+
     template <typename StateObject, typename BackendObject>
     class StateBackendObjectRegistry {
     public:
@@ -129,7 +204,28 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // Twin creation is the moment a driver-owned id starts needing a guarded
             // destructor; cold path, so the once-guard costs nothing per draw.
             EnsureProcessTeardownSentinel();
+            // Sweep BEFORE the entry reference below exists: the map is open-addressed and an
+            // erase relocates the rest of the probe cluster, so collecting once that reference
+            // is taken would invalidate it. The sweep is therefore owed from an earlier call
+            // rather than triggered by this one.
+            if (m_creationTick >= kCreationGCInterval) {
+                m_creationTick = 0;
+                CollectGarbage();
+            }
+            const SizeT entryCountBeforeInsert = m_entries.size();
             auto& entry = m_entries[stateObj.get()];
+            if (m_entries.size() != entryCountBeforeInsert) {
+                // A key the registry has never held. Nothing tells the backend that a texture or
+                // renderbuffer was DELETED - the twin, and the driver storage it owns, lives
+                // until a collection - and CollectGarbageIfNeeded is ticked only from the
+                // per-draw sync paths, which a CTS-shaped workload runs about ten times per
+                // case. 1024 of those ticks then span ~100 cases, so ~100 cases' worth of dead
+                // (and, for this suite, gigabyte-sized) objects stay allocated at once. Object
+                // CHURN rather than draw count is what makes the sweep urgent, so a twin the
+                // registry has never seen ticks it too - and it does so on the path that is
+                // about to allocate, which is exactly when the memory is needed.
+                ++m_creationTick;
+            }
             if (entry.stateRef.expired()) {
                 // The previous owner of this address is gone and the allocator handed it
                 // to a new object: its twin describes ids the new state object never made.
@@ -203,8 +299,12 @@ namespace MobileGL::MG_Backend::DirectGLES {
 
     private:
         static constexpr Uint32 kGCInterval = 1024;
+        // Creations are far rarer than draws, so this counts in a much smaller unit than
+        // kGCInterval does.
+        static constexpr Uint32 kCreationGCInterval = 64;
         BackendMap m_entries;
         Uint32 m_gcTick = 0;
+        Uint32 m_creationTick = 0;
         Bool m_isCollecting = false;
     };
 
@@ -346,6 +446,14 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // client-attribute staging buffers): scrub every buffer-binding shadow that
         // could false-skip when the name is recycled.
         void NoteBufferIdDeleted(Uint id);
+        // Bumped whenever a live GLESBufferResource's driver id is retired and re-minted
+        // while its frontend buffer stays alive (persistent-map adoption, immutable-store
+        // retire). The VAO twins' baked glVertexAttribPointer / element-array bindings
+        // key on FRONTEND versions, which a backend-side re-mint does not move - without
+        // this generation the driver VAO would keep fetching through the deleted id (or
+        // its retained store) forever. Compared and stamped by
+        // BackendVertexArrayObject::SyncToBackend.
+        extern Uint64 g_bufferBackendIdGeneration;
         // Redundant-bind cache for INDEXED buffer bindings (glBindBufferBase/Range on
         // GL_UNIFORM_BUFFER / GL_SHADER_STORAGE_BUFFER): skips the GL call when the
         // (id, range) already at that index matches, like the array-buffer/texture/
@@ -353,6 +461,13 @@ namespace MobileGL::MG_Backend::DirectGLES {
         void BindBufferBaseCached(GLenum glTarget, Uint index, Uint id);
         void BindBufferRangeCached(GLenum glTarget, Uint index, Uint id, GLintptr offset, GLsizeiptr size);
         void InvalidateIndexedBufferBindingCache();
+        // Re-issues the GL_ATOMIC_COUNTER_BUFFER binding points a program's shaders declare as
+        // GL_SHADER_STORAGE_BUFFER bindings at the reserved slots the transpiled ESSL was built
+        // against (BackendProgramObjectImpl::GetAtomicCounterBindings /
+        // GetAtomicCounterEsslBindingTop). ES has no counter-buffer target at all, so without
+        // this the shader reads a storage block nobody ever bound a buffer to and the buffer the
+        // application bound never reaches the driver.
+        void SyncAtomicCounterBuffers(const Vector<Int>& glBindings, Int esslBindingTop);
         // Buffer-storage pool maintenance. TrimBufferPool evicts over-budget entries
         // (called once per frame from Present); ClearBufferPool drops all pooled ids
         // without glDeleteBuffers (called when the ES context is going away).
@@ -459,12 +574,51 @@ namespace MobileGL::MG_Backend::DirectGLES {
             PendingAttribValueMask& GetPendingAttribValueMaskMemo() { return m_pendingAttribValueMask; }
 
         private:
+            // Narrows one enabled GL_DOUBLE array into a tightly packed float32 stream held in
+            // this VAO's own scratch buffer and declares the attribute against it. ES has no
+            // 64-bit vertex format, but the source bytes are ordinary IEEE-754 doubles and every
+            // fp64 value in every shader is already narrowed to 32 bits (DemoteFloat64Pass), so
+            // narrowing the ARRAY is the coherent completion of that decision rather than
+            // dropping it. Returns false when the stream cannot be built, in which case the
+            // caller must DISABLE the array - leaving a 64-bit array enabled with no pointer is
+            // what the Adreno driver turns into a SIGSEGV at the next draw.
+            Bool SyncFloat64AttributeAsFloat32(Uint attribIndex, const MG_State::GLState::VertexAttribute& attrib,
+                                               Uint32 fetchBaseInstance);
+
+            // What the converted float32 stream in m_convertedAttributeBufferIds[i] was built
+            // from. A hit skips the CPU conversion and the re-upload; the buffer's change serial
+            // is part of the key, so a glBufferSubData into the source invalidates it.
+            struct ConvertedFloat64Stream {
+                Bool valid = false;
+                Uint64 sourceLifetimeId = 0;
+                Uint64 sourceChangeSerial = 0;
+                SizeT sourceOffset = 0;
+                SizeT sourceStride = 0;
+                SizeT componentCount = 0;
+                SizeT elementCount = 0;
+            };
+
             ResolvedDrawBuffers m_resolvedDrawBuffers;
             PendingAttribValueMask m_pendingAttribValueMask;
             Uint m_backendVAOId = 0;
             Array<Uint, MG_State::GLState::VertexArrayObject::MAX_VERTEX_ATTRIBS> m_clientAttributeBufferIds;
+            // Scratch stores for the buffer-backed GL_DOUBLE narrowing. Deliberately separate
+            // from m_clientAttributeBufferIds: that one holds the per-draw upload of a
+            // CLIENT-MEMORY array, and an attribute index can carry both shapes over its life.
+            Array<Uint, MG_State::GLState::VertexArrayObject::MAX_VERTEX_ATTRIBS> m_convertedAttributeBufferIds;
+            Array<ConvertedFloat64Stream, MG_State::GLState::VertexArrayObject::MAX_VERTEX_ATTRIBS>
+                m_convertedAttributeStreams;
+            // True while at least one attribute of this VAO is fed by a converted stream. Such a
+            // stream is derived from buffer CONTENT, which no VAO version covers, so the config
+            // version early-out in SyncToBackend must not be trusted while it is set.
+            Bool m_hasConvertedFloat64Attribute = false;
             Bool m_isInitialized = false;
             Uint16 m_syncedIndexBufferVersion = 0;
+            // Identity of the buffer the version above was stamped against. Raw and never
+            // dereferenced: the slot version is a wrapping Uint16 (see the ResolvedDrawBuffers
+            // IBO memo and the packed_pixels postmortem at BindCurrentFBO), so the version
+            // alone would read a wrapped-back count with a different buffer bound as clean.
+            const MG_State::GLState::BufferObject* m_syncedIndexBufferObject = nullptr;
             // Aggregate gate over the per-attribute walk below: the frontend bumps its config
             // version on every per-attribute version bump (the three Bump*Version functions are
             // its only writers), so an unchanged config version proves every per-attribute
@@ -480,6 +634,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // Kept here because it describes what was last EMITTED, which is what the next sync
             // has to correct.
             Uint32 m_syncedFetchBaseInstance = 0;
+            // BufferImpl::g_bufferBackendIdGeneration as of this twin's last emit. A
+            // mismatch means some live buffer's driver id was re-minted since; the ids
+            // baked into the driver VAO's attribute/element bindings may be dead even
+            // though every frontend version matches, so the next sync re-emits them all.
+            Uint64 m_syncedBufferIdGeneration = 0;
         };
 
         extern StateBackendObjectRegistry<MG_State::GLState::VertexArrayObject, BackendVertexArrayObject>
@@ -586,9 +745,21 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // Returns `data` untouched when no widening applies. Pure CPU and context-free so a unit
         // test can exercise the exact packing the driver is handed; `widenedData` is the caller's
         // scratch buffer and has to outlive the returned pointer.
+        // `alphaOneCodeOverride`, when non-zero, replaces the value written into the synthetic
+        // alpha channel: an image carrier that holds a NORMALIZED format's channel CODES has to
+        // pad alpha with that channel's saturated CODE (65535, 32767, 3), which neither of the
+        // transfer type's own "ones" is.
         const void* PrepareChannelWidenedUpload(Uint componentCount, const IntVec3& texelSize, const void* data,
                                                 SizeT byteSize, GLenum uploadType, Vector<Uint8>& widenedData,
-                                                Bool integerData = false);
+                                                Bool integerData = false, Uint32 alphaOneCodeOverride = 0u);
+
+        // Splits a GL_UNSIGNED_INT_2_10_10_10_REV shadow (rgb10_a2, rgb10_a2ui) into the four
+        // GL_UNSIGNED_SHORT channel CODES its GL_RGBA16UI image carrier is uploaded as: red in
+        // bits 0-9, green 10-19, blue 20-29, alpha 30-31. Pure CPU and context-free so a unit test
+        // can pin the exact fields; `widenedData` is the caller's scratch and has to outlive the
+        // returned pointer.
+        const void* PreparePackedIntWidenedUpload(const IntVec3& texelSize, const void* data, SizeT byteSize,
+                                                  Vector<Uint8>& widenedData);
 
         struct StateTextureBasicInfo { // Used for tracking texture state changes
             TextureInternalFormat internalFormat = TextureInternalFormat::Unknown;
@@ -623,10 +794,24 @@ namespace MobileGL::MG_Backend::DirectGLES {
             void SyncMipmapsToBackend(const SharedPtr<MG_State::GLState::ITextureObject>& stateTextureObject);
             void SyncBuiltinSamplerToBackend(const SharedPtr<MG_State::GLState::ITextureObject>& stateTextureObject);
             void SyncTextureParamsToBackend(const SharedPtr<MG_State::GLState::ITextureObject>& stateTextureObject);
-            void RequireImageBindableStorage();
+            // Marks the texture as one whose ES storage has to be image-bindable, which for a
+            // non-core image format means re-minting it in the widening's carrier. Takes the state
+            // object because the levels already uploaded have to be marked dirty again: the
+            // re-mint allocates fresh storage and only replays what the shadow still calls dirty.
+            void RequireImageBindableStorage(
+                const SharedPtr<MG_State::GLState::ITextureObject>& stateTextureObject);
+            // Whether this texture's ES storage was minted in an image carrier rather than in the
+            // frontend format's own layout - the readback has to ask, because for a NORMALIZED
+            // carrier the storage is an integer texture holding codes and glGetTexImage still owes
+            // the application floats.
+            Bool RequiresImageBindableStorage() const { return m_imageBindableStorageRequired; }
             void Bind(GLenum target, Uint unit = TempTextureUnit);
             Uint GetBackendTextureId() const;
 
+            // The id to hand glBindImageTexture for a SPLIT buffer image, or 0 when this texture
+            // takes no split. See m_bufferImageSplitViewId.
+            Uint GetBufferImageSplitViewId() const { return m_bufferImageSplitViewId; }
+
             // Aggregate first-level clean gate for the per-draw trio
             // SyncTextureParamsToBackend + SyncBuiltinSamplerToBackend +
             // SyncMipmapsToBackend: EXACTLY the conjunction of their own early-outs
@@ -663,6 +848,25 @@ namespace MobileGL::MG_Backend::DirectGLES {
             void RecreateBackendTexture();
 
             Uint m_backendTextureId = 0;
+            // A SECOND buffer-texture name over the SAME buffer object, viewed in the split's
+            // single-channel base format, used only as the glBindImageTexture target.
+            //
+            // The split needs the view to say r32f where the application said rg32f, but a buffer
+            // texture that is image-bound may ALSO be read through a samplerBuffer - and the
+            // sampler side is not subscript-rewritten, so re-describing the application's own
+            // texture broke it: texelFetch(s, i) returned component 2i of the base view instead of
+            // texel i's pair. That is exactly and only
+            // KHR-GL42/43.shader_image_load_store.advanced-sync-imageAccess, which image-stores
+            // into a GL_RG32F buffer texture and then reads the same texture through both an
+            // imageBuffer and a samplerBuffer in one shader, comparing the two.
+            //
+            // Two names over one buffer cost nothing and alias exactly: a buffer texture owns no
+            // storage, so both views are the application's bytes, and the split's whole premise is
+            // that the two describe the same memory. The application's own name therefore keeps
+            // the format it asked for - rg32f IS a legal SAMPLED buffer-texture format in ES 3.2,
+            // it is only the IMAGE binding ES cannot spell - and the private name below carries
+            // the split the shader was rewritten against. 0 when this texture takes no split.
+            Uint m_bufferImageSplitViewId = 0;
             // ES context generation the id was created under; a dtor running after
             // that context died must not delete a foreign (recycled) name.
             Uint m_contextGeneration = 0;
@@ -799,6 +1003,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
 
             using FramebufferObject = MG_State::GLState::FramebufferObject;
             FramebufferObject::FramebufferAttachmentVersionArray m_syncedFrontendAttachmentVersions = {0};
+            // g_attachmentBackendIdGeneration as of this twin's last attachment walk. A
+            // mismatch means some backend texture id was re-minted since, and any of this
+            // twin's attachment points may still hold the dead id even though the frontend
+            // attachment versions match - so the walk re-attaches everything first.
+            Uint64 m_syncedBackendIdGeneration = 0;
         };
 
         extern StateBackendObjectRegistry<MG_State::GLState::FramebufferObject, BackendFramebufferObject>
@@ -888,6 +1097,19 @@ namespace MobileGL::MG_Backend::DirectGLES {
         extern Array<MG_State::GLState::FramebufferObject*, SizeT(FramebufferTarget::FramebufferTargetCount)>
             g_fboSyncedObjects;
 
+        // Bumped whenever a live backend texture's driver id is re-minted while its
+        // frontend texture may still be attached to application FBOs
+        // (BackendTextureObject::RecreateBackendTexture - e.g. a respecify of a texture
+        // whose backend storage went immutable). The FBO twins' attachment memos key on
+        // FRONTEND attachment versions, which a backend-side re-mint does not move, so
+        // the driver FBO would keep the deleted texture name attached forever. The
+        // SyncCurrentFBO gate compares this generation (below) to re-enter the sync,
+        // and each twin re-arms its per-attachment memo on a mismatch (SyncToBackend).
+        extern Uint64 g_attachmentBackendIdGeneration;
+        // What g_attachmentBackendIdGeneration was when SyncCurrentFBO last stamped each
+        // target; part of the synced tuple above.
+        extern Array<Uint64, SizeT(FramebufferTarget::FramebufferTargetCount)> g_fboSyncedBackendIdGenerations;
+
         // Driver-level READ/DRAW framebuffer-binding shadow. Every backend
         // glBindFramebuffer routes through BindFramebufferId so scoped helpers can
         // save/restore the current binding without a glGetIntegerv round-trip (that
@@ -991,23 +1213,51 @@ namespace MobileGL::MG_Backend::DirectGLES {
     // Image uniforms take their unit from the layout(binding=N) qualifier baked into
     // the transpiled ESSL; unlike samplers they must not (and in ES cannot) be
     // assigned through glUniform1i.
+    //
+    // ALL THIRTY-THREE of them, in the one contiguous block ARB_shader_image_load_store allocated
+    // (GL_IMAGE_1D 0x904C through GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE_ARRAY 0x906C). The list
+    // used to hold only the fifteen whose TARGET exists in ES, which read as a reasonable
+    // shortcut and was two bugs: an image uniform this says "no" to is one
+    // CollectImageFormatBakeInputs never walks, so its non-core format is neither baked nor
+    // widened and SPIRV-Cross throws for the whole stage ("Attempting to use image format not
+    // supported in ES profile"), and it is also one SyncToBackend then treats as a SAMPLER and
+    // assigns with glUniform1i, which ES makes an INVALID_OPERATION. A GL_TEXTURE_CUBE_MAP_ARRAY
+    // image - which ES 3.2 has in core, so it is not even an emulated target - hit both.
     inline Bool IsImageUniformType(GLenum type) {
         switch (type) {
+        case 0x904C: /*GL_IMAGE_1D*/
         case 0x904D: /*GL_IMAGE_2D*/
         case 0x904E: /*GL_IMAGE_3D*/
+        case 0x904F: /*GL_IMAGE_2D_RECT*/
         case 0x9050: /*GL_IMAGE_CUBE*/
         case 0x9051: /*GL_IMAGE_BUFFER*/
+        case 0x9052: /*GL_IMAGE_1D_ARRAY*/
         case 0x9053: /*GL_IMAGE_2D_ARRAY*/
+        case 0x9054: /*GL_IMAGE_CUBE_MAP_ARRAY*/
+        case 0x9055: /*GL_IMAGE_2D_MULTISAMPLE*/
+        case 0x9056: /*GL_IMAGE_2D_MULTISAMPLE_ARRAY*/
+        case 0x9057: /*GL_INT_IMAGE_1D*/
         case 0x9058: /*GL_INT_IMAGE_2D*/
         case 0x9059: /*GL_INT_IMAGE_3D*/
+        case 0x905A: /*GL_INT_IMAGE_2D_RECT*/
         case 0x905B: /*GL_INT_IMAGE_CUBE*/
         case 0x905C: /*GL_INT_IMAGE_BUFFER*/
+        case 0x905D: /*GL_INT_IMAGE_1D_ARRAY*/
         case 0x905E: /*GL_INT_IMAGE_2D_ARRAY*/
+        case 0x905F: /*GL_INT_IMAGE_CUBE_MAP_ARRAY*/
+        case 0x9060: /*GL_INT_IMAGE_2D_MULTISAMPLE*/
+        case 0x9061: /*GL_INT_IMAGE_2D_MULTISAMPLE_ARRAY*/
+        case 0x9062: /*GL_UNSIGNED_INT_IMAGE_1D*/
         case 0x9063: /*GL_UNSIGNED_INT_IMAGE_2D*/
         case 0x9064: /*GL_UNSIGNED_INT_IMAGE_3D*/
+        case 0x9065: /*GL_UNSIGNED_INT_IMAGE_2D_RECT*/
         case 0x9066: /*GL_UNSIGNED_INT_IMAGE_CUBE*/
         case 0x9067: /*GL_UNSIGNED_INT_IMAGE_BUFFER*/
+        case 0x9068: /*GL_UNSIGNED_INT_IMAGE_1D_ARRAY*/
         case 0x9069: /*GL_UNSIGNED_INT_IMAGE_2D_ARRAY*/
+        case 0x906A: /*GL_UNSIGNED_INT_IMAGE_CUBE_MAP_ARRAY*/
+        case 0x906B: /*GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE*/
+        case 0x906C: /*GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE_ARRAY*/
             return true;
         default:
             return false;
@@ -1015,6 +1265,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
     }
 
     namespace PrgramImpl {
+        // Defined further down, next to CollectImageFormatBakeInputs; only referenced here.
+        struct ImageFormatBakeInputs;
+
         class BackendProgramObjectImpl {
         public:
             // Per-link cache of a sampler-style uniform's backend location: built once in
@@ -1074,7 +1327,7 @@ namespace MobileGL::MG_Backend::DirectGLES {
             BackendProgramObjectImpl();
             ~BackendProgramObjectImpl();
             void SyncToBackend(const SharedPtr<MG_State::GLState::ProgramObject>& stateProgramObject);
-            void Use() const;
+            void Use();
             void SetBaseInstance(Uint32 baseInstance) const;
             void SetBaseInstanceWordIndex(Int32 wordIndex) const;
             void SetDrawID(Uint32 drawId) const;
@@ -1085,6 +1338,14 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // Same for gl_BaseVertex: only a program that reads it pays for the per-draw
             // uniform write, and only such a program needs the reset after one.
             Bool ReadsBaseVertex() const { return m_baseVertexUniformLocation >= 0; }
+            // Which viewport indices the next draw's fragments may keep, one bit each. Written
+            // once per replay pass; see ForEachViewportRoutingPass.
+            void SetViewportPassMask(Uint32 indexMask) const;
+            // True when this build injected the fragment-stage viewport gate, i.e. when a
+            // pre-rasterization stage routes by gl_ViewportIndex AND the fragment stage can act
+            // on it. The uniform is the honest test for both halves: it exists only where the
+            // gate was injected, and the gate is injected only where a stage routes.
+            Bool RoutesViewportIndex() const { return m_viewportPassMaskUniformLocation >= 0; }
             Int GetIndirectParamsBinding() const { return m_indirectParamsBinding; }
             Uint GetBackendProgramId() const { return m_backendProgramId; }
             // False when the last SyncToBackend could not produce a usable program (a
@@ -1100,6 +1361,22 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // qualifier, so the overrides are baked into the source). A mismatch means the
             // program is stale exactly like the clamp masks above.
             Uint64 GetShaderStorageBlockBindingSignature() const { return m_shaderStorageBlockBindingSignature; }
+            // GL atomic-counter binding points the transpiled stages declare (sorted, unique),
+            // and the top of the reserved shader-storage range their counter blocks were
+            // transpiled against - the slot for GL binding N is `top - N`. Empty for every
+            // program that uses no atomic counter, which is what keeps the per-draw cost of the
+            // counter sync at one empty-vector test.
+            const Vector<Int>& GetAtomicCounterBindings() const { return m_atomicCounterGlBindings; }
+            Int GetAtomicCounterEsslBindingTop() const { return m_atomicCounterEsslBindingTop; }
+            // GL_PATCH_VERTICES the synthesized pass-through tessellation control stage was built
+            // for, or -1 when this program needed no such stage. Another of the same shape as the
+            // signatures above: the value is compiled INTO the synthesized stage as
+            // `layout(vertices = N) out`, so a program built for one patch size is stale for
+            // another and the draw path has to say so. -1 compares equal to itself for every
+            // program that has a control stage of its own, i.e. for all but a handful.
+            Int GetPassthroughTessControlPatchVertices() const {
+                return m_passthroughTessControlPatchVertices;
+            }
 
             Bool HasGlobalUboBlock() const { return m_globalUboBackendBlockIndex >= 0; }
             const Vector<Int>& GetUniformBlockBackendIndices() const { return m_uniformBlockBackendIndices; }
@@ -1122,10 +1399,59 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // stale as one built before a relink - while the sampler half, which really is
             // re-issued per draw, needs nothing of the sort.
             Uint32 GetSyncedImageUnitVersion() const { return m_syncedImageUnitVersion; }
+            // Whether the (unit, bound format) pairs this program's FORMAT-LESS image uniforms
+            // resolve to are still the ones its ESSL was generated against.
+            //
+            // A fourth condition of the same family as the three above, and the only one that
+            // reads live state rather than a program-side counter, because that is where the
+            // dependency actually is. GLSL ES requires a format layout qualifier on every image
+            // where desktop GLSL lets a writeonly declaration omit one, and the only correct
+            // qualifier is whatever glBindImageTexture named - so a declaration with no format
+            // is compiled against the BINDING, and a rebind to a different format makes the
+            // built program wrong. Keyed on the units the program's own images address (cached
+            // at sync, since a unit can only move by glUniform1i, which bumps the image-unit
+            // version above and forces a re-sync anyway), so the cost on a program with no
+            // format-less image - which is all but a handful - is one empty-vector test.
+            //
+            // Deliberately NOT reached from glBindImageTexture: that entry point must never
+            // trigger a build (same constraint as glShaderStorageBlockBinding). It moves the
+            // state and this comparison notices at the next Prepare, which is also what makes
+            // an image first bound AFTER link work.
+            Bool ImageUnitFormatsStillMatch() const;
+            // The value ImageUnitFormatsStillMatch() compares against, recomputed from live
+            // image-unit state. 0 when the program has no format-less image uniform.
+            Uint64 ComputeImageUnitFormatSignature() const;
 
         private:
             void CacheResourceLocations(const SharedPtr<MG_State::GLState::ProgramObject>& stateProgramObject);
 
+            // Builds, compiles and attaches the pass-through tessellation control stage GL 4.6
+            // core 11.2.2 describes, for a program that has an evaluation stage and none of its
+            // own - which ES 3.2 rejects outright. Called from SyncToBackend after every real
+            // stage has been attached and before the link; see the definition for why it cannot
+            // regress a program that works today.
+            void AttachPassthroughTessControlStage(
+                const MG_State::GLState::ProgramObject& stateProgramObject, Int tessEvalShaderIndex,
+                const Vector<Vector<unsigned int>>& shaderSpirvs, const String& vertexStageEssl,
+                const String& tessEvalStageEssl);
+
+            // One stage's SPIR-V through the DirectGLES pass chain and SPIRV-Cross, producing
+            // the raw emitted ESSL and the interface blocks this stage's XFB flattening
+            // rewrote. This is the segment the L2 shader-translation memo keys on, so every
+            // input it reads must appear in EsslTranslationKeyInputs - see the definition's
+            // header comment in Managers.cpp and MG_Util/ShaderTranspiler/TranslationCache.h.
+            // False means SPIRV-Cross refused the module; `outError` then carries its message.
+            Bool TranspileSpirvToEssl(const Vector<unsigned int>& spirvCode, GLenum glShaderType,
+                                      const std::set<String>& xfbCaptureBlockNames,
+                                      const ImageFormatBakeInputs& imageFormatBake,
+                                      const UnorderedMap<String, Int>& storageBlockBindingOverrides,
+                                      const std::map<String, String>& inputBlockRenames,
+                                      const std::map<String, String>& outputBlockRenames,
+                                      Int atomicCounterEsslBindingTop, Bool enableSpirvValidation,
+                                      String& outSource,
+                                      std::set<String>& outFlattenedXfbBlockNames,
+                                      Vector<Int>& outAtomicCounterGlBindings, String& outError) const;
+
             Uint m_backendProgramId = 0;
             // GL name of the frontend program this was last synced from; diagnostics only, so
             // an unusable backend program can be traced back to the glCreateProgram id the app
@@ -1136,6 +1462,7 @@ namespace MobileGL::MG_Backend::DirectGLES {
             Int m_drawIdUniformLocation = -1;
             Int m_baseVertexUniformLocation = -1;
             Int m_baseInstanceWordIndexUniformLocation = -1;
+            Int m_viewportPassMaskUniformLocation = -1;
             Int m_indirectParamsBinding = -1;
             Uint32 m_snormFallbackClampOutputMask = 0;
             Uint32 m_unormFallbackClampOutputMask = 0;
@@ -1144,8 +1471,19 @@ namespace MobileGL::MG_Backend::DirectGLES {
             Uint m_fragColorBroadcastCount = 1;
             // 0 is the signature of an empty override set, i.e. what almost every program has.
             Uint64 m_shaderStorageBlockBindingSignature = 0;
+            Vector<Int> m_atomicCounterGlBindings;
+            Int m_atomicCounterEsslBindingTop = -1;
+            // -1 for every program that has a tessellation control stage of its own (or none at
+            // all); otherwise the GL_PATCH_VERTICES the synthesized pass-through stage was built
+            // with. See GetPassthroughTessControlPatchVertices.
+            Int m_passthroughTessControlPatchVertices = -1;
             Bool m_isInitialized = false;
             Bool m_backendProgramUsable = false;
+            // Set by SyncToBackend every time it relinks the driver program, cleared by the
+            // next Use(). Use() dedupes on a GL program NAME, and a relink replaces the
+            // executable behind that name without changing it - see the note at the
+            // glLinkProgram in SyncToBackend for what the driver runs otherwise.
+            Bool m_rebindAfterRelink = false;
 
             Int m_globalUboBackendBlockIndex = -1;
             Int m_globalUboBackendBlockSize = 0;
@@ -1155,6 +1493,12 @@ namespace MobileGL::MG_Backend::DirectGLES {
             BufferImpl::UboRingAllocation m_globalUboRingAllocation;
             Uint32 m_syncedLinkVersion = ~0u;
             Uint32 m_syncedImageUnitVersion = ~0u;
+            // Image units addressed by the program's FORMAT-LESS image uniforms, and the digest
+            // of the (unit, format) pairs the generated ESSL baked. Empty/0 for every program
+            // that declares a format on all of its images, which is the overwhelming majority -
+            // and what keeps the per-draw comparison free for them.
+            Vector<Int> m_formatlessImageUnits;
+            Uint64 m_imageUnitFormatSignature = 0;
             SamplerPassMemo m_samplerPassMemo;
         };
 
@@ -1198,6 +1542,48 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // already has costs nothing. 0 when nothing was ever rebound.
         Uint64 ComputeShaderStorageBlockBindingSignature(
             const MG_State::GLState::ProgramObject& stateProgramObject);
+
+        // Everything the image-format bake needs from one walk of a program's uniform
+        // reflection. GLSL ES requires a format layout qualifier on every image uniform;
+        // desktop GLSL lets a writeonly (or readonly) declaration omit one, and the only
+        // format that is CORRECT to substitute is whatever glBindImageTexture named for the
+        // unit that uniform addresses - so the transpile bakes it in and the build is keyed
+        // on it.
+        struct ImageFormatBakeInputs {
+            // Uniform name (SPIR-V spelling, i.e. an array named once, unsubscripted) to the GL
+            // internal format to bake. Holds only uniforms that DECLARED no format; a declared
+            // one is authoritative and is never overridden.
+            UnorderedMap<String, Uint> glFormatByUniformName;
+            // The same uniforms whose format SPIRV-Cross REFUSES to print for ESSL (it throws on
+            // its desktop-only set, which loses the stage), paired with the ESSL spelling to
+            // write into the emitted declaration instead. Disjoint from the map above by
+            // construction: a format is baked into the module or completed in the text, never
+            // both. r8ui - the stencil half of the packed_depth_stencil case - lands here.
+            UnorderedMap<String, String> esslFormatQualifierByUniformName;
+            // Units those uniforms address, kept so the draw path can re-read their formats
+            // without walking the reflection again.
+            Vector<Int> units;
+            // Digest of the (unit, format) pairs above. 0 when the program has no format-less
+            // image uniform, which is all but a handful.
+            Uint64 signature = 0;
+            // Array uniforms whose elements resolved to units holding DIFFERENT formats: one
+            // declaration carries one qualifier, so there is nothing correct to bake and they
+            // are dropped from the map above. Kept for diagnostics.
+            Vector<String> conflictedNames;
+            // Some format in play - declared or baked - is outside the GLSL ES core image
+            // format set, so the emitted ESSL needs the GL_NV_image_formats directive.
+            Bool needsExtendedImageFormats = false;
+            // Some DECLARED format in play is one WidenImageFormatsForEssl will re-declare in a
+            // core carrier. Answered from the uniform reflection rather than from a module parse
+            // on purpose: the widening is armed on every driver, so a per-stage BuildModule to
+            // find out would land on every stage of every program - which is the cost
+            // SpirvGateFeatures exists to avoid. Program-wide, so it can over-arm a stage that
+            // declares no image; the pass then finds nothing, reports no change, and the caller
+            // keeps the module it already had.
+            Bool declaresWidenableImageFormat = false;
+        };
+        ImageFormatBakeInputs CollectImageFormatBakeInputs(
+            const MG_State::GLState::ProgramObject& stateProgramObject);
     } // namespace PrgramImpl
 
     namespace SamplerImpl {

MobileGL/MG_Backend/DirectGLES/MultiDraw.cpp

@@ -252,7 +252,7 @@ namespace MobileGL::MG_Backend::DirectGLES::MultiDrawImpl {
             g_resolvedTier =
                 ResolveTier(g_GLESCapabilities, g_GLESFuncs, MG_Config::Features.EsprytMultiDrawMode,
                             &g_tierResolution);
-            MGLOG_I("DirectGLES multi-draw: %s", g_tierResolution.c_str());
+            MGLOG_D("DirectGLES multi-draw: %s", g_tierResolution.c_str());
         }
 
         // Which tiers have already announced themselves, one bit per GLESMultiDrawMode.
@@ -267,7 +267,7 @@ namespace MobileGL::MG_Backend::DirectGLES::MultiDrawImpl {
             const Uint32 bit = 1u << static_cast<Uint32>(tier);
             if (g_announcedTiers & bit) return;
             g_announcedTiers |= bit;
-            MGLOG_I("DirectGLES multi-draw: first batch executed via tier \"%s\"", TierName(tier));
+            MGLOG_D("DirectGLES multi-draw: first batch executed via tier \"%s\"", TierName(tier));
         }
 
         // The tier this particular batch can actually take. A tier is demoted here when
@@ -414,14 +414,18 @@ namespace MobileGL::MG_Backend::DirectGLES::MultiDrawImpl {
             const Uint previousIndirectBinding = BoundDrawIndirectBufferId();
             BufferImpl::BindBufferId(GL_DRAW_INDIRECT_BUFFER, g_indirectCommands.id);
             if (batched) {
-                g_GLESFuncs.glMultiDrawElementsIndirectEXT(mode, type, reinterpret_cast<const void*>(commandBase),
-                                                           drawcount, 0);
+                ForEachViewportRoutingPass([&] {
+                    g_GLESFuncs.glMultiDrawElementsIndirectEXT(mode, type, reinterpret_cast<const void*>(commandBase),
+                                                               drawcount, 0);
+                });
             } else {
                 for (GLsizei i = 0; i < drawcount; ++i) {
                     if (feedDrawID) SetCurrentDrawID(static_cast<Uint32>(i));
                     if (feedBaseVertex) SetCurrentBaseVertex(basevertex ? basevertex[i] : 0);
                     const SizeT commandOffset = commandBase + static_cast<SizeT>(i) * sizeof(DrawElementsIndirectCommand);
-                    g_GLESFuncs.glDrawElementsIndirect(mode, type, reinterpret_cast<const void*>(commandOffset));
+                    ForEachViewportRoutingPass([&] {
+                        g_GLESFuncs.glDrawElementsIndirect(mode, type, reinterpret_cast<const void*>(commandOffset));
+                    });
                 }
                 if (feedDrawID) SetCurrentDrawID(0);
                 if (feedBaseVertex) SetCurrentBaseVertex(0);
@@ -442,8 +446,10 @@ namespace MobileGL::MG_Backend::DirectGLES::MultiDrawImpl {
                 if (count[i] <= 0) continue;
                 if (feedDrawID) SetCurrentDrawID(static_cast<Uint32>(i));
                 if (feedBaseVertex) SetCurrentBaseVertex(basevertex ? basevertex[i] : 0);
-                g_GLESFuncs.glDrawElementsBaseVertex(mode, count[i], type, indices[i],
-                                                     basevertex ? basevertex[i] : 0);
+                ForEachViewportRoutingPass([&] {
+                    g_GLESFuncs.glDrawElementsBaseVertex(mode, count[i], type, indices[i],
+                                                         basevertex ? basevertex[i] : 0);
+                });
             }
             if (feedDrawID) SetCurrentDrawID(0);
             if (feedBaseVertex) SetCurrentBaseVertex(0);
@@ -490,7 +496,7 @@ namespace MobileGL::MG_Backend::DirectGLES::MultiDrawImpl {
                 const Uint8* source = ResolveSubDrawIndices(indexBuffer, indexBufferBytes, indexBufferSize, indices[i],
                                                             subDrawCount, indexSize);
                 if (!source) {
-                    MGLOG_E("DirectGLES multi-draw (drawelements tier): sub-draw %d reads outside the bound index "
+                    MGLOG_E_ONCE("DirectGLES multi-draw (drawelements tier): sub-draw %d reads outside the bound index "
                             "buffer; skipping the batch",
                             i);
                     return false;
@@ -515,8 +521,10 @@ namespace MobileGL::MG_Backend::DirectGLES::MultiDrawImpl {
                 // driver sees none - but gl_BaseVertex still has to report the value the
                 // application passed for this sub-draw.
                 if (feedBaseVertex) SetCurrentBaseVertex(basevertex ? basevertex[i] : 0);
-                g_GLESFuncs.glDrawElements(mode, count[i], GL_UNSIGNED_INT,
-                                           reinterpret_cast<const void*>(indexBase + cursor * sizeof(Uint32)));
+                ForEachViewportRoutingPass([&] {
+                    g_GLESFuncs.glDrawElements(mode, count[i], GL_UNSIGNED_INT,
+                                               reinterpret_cast<const void*>(indexBase + cursor * sizeof(Uint32)));
+                });
                 cursor += static_cast<SizeT>(count[i]);
             }
             if (feedDrawID) SetCurrentDrawID(0);
@@ -596,7 +604,7 @@ void main() {
 
             const GLuint shader = g_GLESFuncs.glCreateShader(GL_COMPUTE_SHADER);
             if (shader == 0) {
-                MGLOG_E("DirectGLES multi-draw (compute tier): glCreateShader(GL_COMPUTE_SHADER) failed");
+                MGLOG_E_ONCE("DirectGLES multi-draw (compute tier): glCreateShader(GL_COMPUTE_SHADER) failed");
                 return false;
             }
             const char* source = kFlattenComputeSource;
@@ -607,14 +615,14 @@ void main() {
             if (status != GL_TRUE) {
                 char log[1024] = {};
                 g_GLESFuncs.glGetShaderInfoLog(shader, sizeof(log) - 1, nullptr, log);
-                MGLOG_E("DirectGLES multi-draw (compute tier): index-flattening shader failed to compile: %s", log);
+                MGLOG_E_ONCE("DirectGLES multi-draw (compute tier): index-flattening shader failed to compile: %s", log);
                 g_GLESFuncs.glDeleteShader(shader);
                 return false;
             }
 
             const GLuint program = g_GLESFuncs.glCreateProgram();
             if (program == 0) {
-                MGLOG_E("DirectGLES multi-draw (compute tier): glCreateProgram failed");
+                MGLOG_E_ONCE("DirectGLES multi-draw (compute tier): glCreateProgram failed");
                 g_GLESFuncs.glDeleteShader(shader);
                 return false;
             }
@@ -625,7 +633,7 @@ void main() {
             if (status != GL_TRUE) {
                 char log[1024] = {};
                 g_GLESFuncs.glGetProgramInfoLog(program, sizeof(log) - 1, nullptr, log);
-                MGLOG_E("DirectGLES multi-draw (compute tier): index-flattening program failed to link: %s", log);
+                MGLOG_E_ONCE("DirectGLES multi-draw (compute tier): index-flattening program failed to link: %s", log);
                 g_GLESFuncs.glDeleteProgram(program);
                 return false;
             }
@@ -635,7 +643,7 @@ void main() {
             g_uDrawCount = g_GLESFuncs.glGetUniformLocation(program, "uDrawCount");
             g_uTotalIndices = g_GLESFuncs.glGetUniformLocation(program, "uTotalIndices");
             g_computeProgramFailed = false;
-            MGLOG_I("DirectGLES multi-draw: index-flattening compute program ready (id %u)", program);
+            MGLOG_D("DirectGLES multi-draw: index-flattening compute program ready (id %u)", program);
             return true;
         }
 
@@ -870,7 +878,9 @@ void main() {
         if (flattened.indexCount != 0) {
             const Uint previousIndexBinding = BoundIndexBufferId();
             BufferImpl::BindBufferId(GL_ELEMENT_ARRAY_BUFFER, flattened.bufferId);
-            g_GLESFuncs.glDrawElements(mode, static_cast<GLsizei>(flattened.indexCount), GL_UNSIGNED_INT, nullptr);
+            ForEachViewportRoutingPass([&] {
+                g_GLESFuncs.glDrawElements(mode, static_cast<GLsizei>(flattened.indexCount), GL_UNSIGNED_INT, nullptr);
+            });
             BufferImpl::BindBufferId(GL_ELEMENT_ARRAY_BUFFER, previousIndexBinding);
             return;
         }
@@ -920,7 +930,7 @@ void main() {
                                            feedBaseVertex);
         }
         if (!drawn) {
-            MGLOG_E("DirectGLES multi-draw: no usable tier for a %d sub-draw batch (mode 0x%x, type 0x%x); "
+            MGLOG_E_ONCE("DirectGLES multi-draw: no usable tier for a %d sub-draw batch (mode 0x%x, type 0x%x); "
                     "the batch was dropped",
                     drawcount, mode, type);
         }

MobileGL/MG_Backend/DirectGLES/Utils.h

@@ -60,6 +60,115 @@ namespace MobileGL::MG_Backend::DirectGLES {
         Bool BackendTextureFormatAddsAlpha(TextureInternalFormat internalFormat, TextureTarget target);
         Bool BackendRenderbufferFormatAddsAlpha(TextureInternalFormat internalFormat);
         Bool ShouldUseCaveatRenderbufferFormat(TextureInternalFormat internalFormat);
+
+        // The CHANNEL WIDENING an image-bindable texture's ES storage takes, so that a format
+        // GLSL ES cannot spell as an image is carried by one it can.
+        //
+        // GL has forty image formats, GLSL ES core has thirteen, and no test device advertises
+        // GL_NV_image_formats - so a shader declaring one of the other twenty-six has no legal
+        // ESSL at all and glBindImageTexture rejects the narrow format outright for most of them
+        // (GL_INVALID_VALUE for nineteen of twenty-six on Adreno, twenty-five on both Malis).
+        // Seventeen have a core format of the SAME per-channel width and component type,
+        // differing only in channel count, and in one of those the emulation is EXACT: GL already
+        // defines an imageLoad from a narrower format as (r, 0, 0, 1) and an imageStore as
+        // dropping the components the format does not have, so the carrier's surplus channels
+        // hold values GL has already named. WidenImageFormatsPass pins them in the shader; this
+        // is the storage half, and DirectGLES::TextureImpl::SyncImageTextureBinding the bind
+        // half. All three ask WidenedCoreEsslImageFormat, so they cannot pick different carriers.
+        //
+        // Reports nothing (InternalFormat == GL_UNKNOWN_MGL) for a format that is core already,
+        // for the nine with no exact carrier (r11f_g11f_b10f, rgb10_a2, rgb10_a2ui, rgba16, rg16,
+        // r16, rgba16_snorm, rg16_snorm, r16_snorm - those keep the honest "no GLSL ES spelling"
+        // diagnostic rather than a silent approximation), and on a driver that HAS
+        // GL_NV_image_formats, where the shader keeps the declared format and no widening may
+        // happen behind it.
+        //
+        // The widened triple REPLACES what GenerateTextureFormatInfo chose, including any
+        // renderability substitution: an image that cannot be image-bound is useless whatever its
+        // attachment behaviour, so the image constraint wins. In practice that only bites
+        // RG8_SNORM/R8_SNORM on a driver without EXT_render_snorm, where the storage stays
+        // signed-normalized instead of becoming the half float that fallback would have picked -
+        // so an image-bound texture in one of those two formats is no longer attachable, and
+        // glGetTexImage on it falls through to the CPU shadow, which a shader-side imageStore
+        // does not update. Accepted deliberately: before the widening, an image binding in either
+        // format was refused outright by every driver tested and the stage that declared it never
+        // compiled at all, so nothing that works today is being given up.
+        //
+        // KNOWN GAP, for the same "all three layers move together" reason: a widened texture that
+        // is ALSO an FBO colour attachment gains one to three writable channels, and a draw into
+        // it can leave values in channels GL says are 0 and 1. Sampling and imageLoad are covered
+        // (the swizzle composition in SyncTextureParamsToBackend and the shader-side mask), but a
+        // glReadPixels/glGetTexImage that asks for more channels than the frontend format has
+        // would see them. Closing it needs the per-draw-buffer colour mask the three-channel
+        // widening already carries (FramebufferImpl::g_alphaWidenedDrawBufferMask) generalized
+        // from "alpha" to a channel count, which is its own change.
+        // How the FRONTEND's CPU shadow for a widened format is laid out relative to the carrier's
+        // transfer, i.e. what the upload has to do to it. Almost every entry is `Components`: the
+        // shadow already holds SourceChannels components of exactly the carrier's own type, so
+        // padding it out to four is the whole conversion. The packed entries do not - their shadow
+        // is ONE 32-bit word per texel - and reading such a word as components of the carrier's
+        // type takes twelve or sixteen bytes out of four and shears the level.
+        enum class ImageWidenSourceEncoding : Uint8 {
+            Components = 0,
+            // r11f_g11f_b10f: GL_UNSIGNED_INT_10F_11F_11F_REV -> four GL_FLOATs of an rgba16f.
+            PackedFloat11f11f10f,
+            // rgb10_a2 and rgb10_a2ui: GL_UNSIGNED_INT_2_10_10_10_REV -> four GL_UNSIGNED_SHORT
+            // channel CODES of an rgba16ui. The same split serves both: the two formats differ
+            // only in what the codes MEAN, which is the shader's business and not the transfer's.
+            PackedInt2101010Rev,
+        };
+
+        struct ImageBindableStorageWidening {
+            GLenum InternalFormat = GL_UNKNOWN_MGL;
+            GLenum Format = GL_UNKNOWN_MGL;
+            GLenum Type = GL_UNKNOWN_MGL;
+            // Channels the FRONTEND format has, i.e. how many of the carrier's four the client
+            // data fills. The rest are uploaded as 0, and the fourth as the format's implied 1.
+            Uint SourceChannels = 0;
+            // Whether that implied 1 is the integer one or a saturated normalized field - the
+            // transfer type cannot tell the two apart (GL_UNSIGNED_BYTE serves both RG8 and
+            // RG8UI), so the carrier decides.
+            Bool IntegerData = false;
+            // What the upload has to do to the frontend shadow before it describes the level to
+            // the driver (PrepareImageWidenedUpload).
+            ImageWidenSourceEncoding SourceEncoding = ImageWidenSourceEncoding::Components;
+            // Non-zero when the carrier holds this format's channels as the INTEGER CODES of a
+            // NORMALIZED value - the seven 16-bit and 10-bit normalized formats, which core ESSL
+            // has no image format of any width for and which a float carrier would requantise.
+            // Each entry is the largest code that channel can hold, i.e. the denominator of GL 4.6
+            // 2.3.5; SignedNormalized picks which of the two conversions it is the denominator of.
+            //
+            // Two things depend on it, both because the ES storage no longer shares the frontend
+            // format's component class: the upload pads a missing alpha with ChannelMax[3] instead
+            // of the transfer type's own "one" (through a uint carrier the saturated field IS the
+            // one), and glGetTexImage divides the codes back out into the floats the application
+            // is still owed.
+            Uint ChannelMax[4] = {0u, 0u, 0u, 0u};
+            Bool SignedNormalized = false;
+
+            Bool CarriesNormalizedCodes() const { return ChannelMax[0] != 0u; }
+            explicit operator Bool() const { return InternalFormat != GL_UNKNOWN_MGL; }
+        };
+        ImageBindableStorageWidening GetImageBindableStorageWidening(TextureInternalFormat internalFormat);
+
+        // The single-channel core format an image-bindable BUFFER texture's view is SPLIT into, or
+        // GL_UNKNOWN_MGL for a format that needs no split (or has no core base).
+        //
+        // A buffer texture cannot be widened: its texels are the application's buffer object, at
+        // the size and layout the application gave it, and it is usually also a vertex, index or
+        // storage buffer whose bytes are not ours to restride. But an rg32f view of N texels and
+        // an r32f view of 2N texels describe exactly the SAME bytes, so the split changes only
+        // how the shader subscripts them - component j of texel i is texel 2i + j of the base
+        // view - which WidenImageFormatsPass rewrites every access to do. The same rule as the
+        // widening decides WHETHER: a driver that can spell rg32f for an imageBuffer needs
+        // nothing.
+        //
+        // KNOWN GAP, and the reason this is not applied to a texture that is merely sampled: a
+        // buffer texture that is BOTH image-bound and read through a samplerBuffer would have its
+        // sampled view split too, and the sampler side is not rewritten. Accepted for the same
+        // reason the storage widening's gaps are - on a driver where the split applies at all
+        // there is no legal ESSL for the image declaration, so such a program did not compile.
+        GLenum GetImageBindableBufferSplitFormat(TextureInternalFormat internalFormat);
     } // namespace TextureImpl
 
     namespace FramebufferImpl {} // namespace FramebufferImpl
@@ -115,6 +224,16 @@ namespace MobileGL::MG_Backend::DirectGLES {
         Bool StoreWideRowsToClient(const Uint8* wide, GLenum wideType, GLsizei width, GLsizei sliceHeight,
                                    GLsizei sliceCount, const ReadbackChannelMapping& mapping, GLenum type,
                                    void* pixels, Bool applyPackImageParams);
+
+        // Stores packed 32-bit source words verbatim, with the same destination addressing, PACK
+        // parameters and pixel-pack-buffer handling as StoreWideRowsToClient. For the sources whose
+        // storage word already IS the client word (MG_Util::IsRawPackedPixelTransfer): routing those
+        // through the wide float intermediate re-encodes them, and the RGB9_E5 encoder canonicalizes
+        // the shared exponent, so glGetTexImage would answer with different bits than were stored.
+        // `srcWords` holds sliceHeight * sliceCount tightly stacked rows of `width` 32-bit words.
+        // False when `type` is not a 4-byte packed type.
+        Bool StorePackedWordsToClient(const Uint8* srcWords, GLsizei width, GLsizei sliceHeight, GLsizei sliceCount,
+                                      GLenum type, void* pixels, Bool applyPackImageParams);
     } // namespace ReadbackImpl
 
     namespace PrgramImpl {
@@ -137,10 +256,144 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // ES 3.2 needs no directive at all and an EXT driver already has the right one.
         String RetargetTextureBufferExtension(String glslCode,
                                               MG_External::GLESCapabilities::TextureBufferTier tier);
+        // Adds `#extension GL_NV_image_formats : require` when the shader carries an image
+        // format qualifier GLSL ES has no core spelling for. SPIRV-Cross prints the format and
+        // asks for nothing, so the request has to be made here. `needed` is the caller's answer,
+        // because only it knows which formats are in play AND whether the driver advertises the
+        // extension - requesting an unadvertised extension is itself a compile error, so this is
+        // never emitted speculatively. A no-op when not needed or already present.
+        String RequestExtendedImageFormats(String glslCode, Bool needed);
+        // Adds `#extension GL_OES_viewport_array : require` when the emitted ESSL names
+        // gl_ViewportIndex. SPIRV-Cross prints that identifier and asks for nothing (unlike
+        // gl_Layer, which it backs with GL_NV_viewport_array2 on ES) and ESSL has no core
+        // spelling for it at any version, so the request has to be made here or the stage does
+        // not compile - which loses the whole program, not just the multi-viewport routing.
+        // `needed` is the caller's answer for the same reason as above: only it knows whether the
+        // driver advertises the extension, and requesting an unadvertised one is itself a compile
+        // error, so this is never emitted speculatively. A no-op when not needed or already
+        // present.
+        String RequestViewportArrayExtension(String glslCode, Bool needed);
+        // Writes a format layout qualifier into the image declarations named in
+        // `esslFormatByUniformName` that still have none. The completion half of the image-format
+        // bake, and ONLY that: the SPIR-V pass (BakeImageFormatsPass) is what normally puts the
+        // format in, but SPIRV-Cross throws rather than printing the formats it calls
+        // desktop-only when it targets ESSL - r8ui among them, which is what the stencil half of
+        // KHR-GL4x.packed_depth_stencil.stencil_texturing binds - and a throw loses the whole
+        // stage. So those formats stay out of the module and are spelled here instead, on the
+        // emitted text, where nothing can refuse them.
+        //
+        // Declarations that already carry a format are left exactly as they are, whoever wrote
+        // it. Must run before RemoveLayoutBinding, which is where an image's layout qualifier
+        // stops being safe to edit by hand.
+        String BakeImageFormatQualifiers(String glslCode, const UnorderedMap<String, String>& esslFormatByUniformName);
         String RemoveLayoutBinding(const String& glslCode);
+        // Prefix of the per-element scalar declarations RemapImageArrayElementUnits splits an
+        // image array into; the suffix is the array's own name and the element's index.
+        constexpr const char* IMAGE_ARRAY_ELEMENT_PREFIX = "mg_imageElem_";
+        // One image ARRAY whose elements the application pointed at units that are not
+        // consecutive-from-element-zero.
+        struct ImageArrayUnitPlan {
+            String name;       // the array's name, exactly as the emitted ESSL declares it
+            Vector<Int> units; // the frontend image unit element k has to reach
+        };
+        // Desktop GL lets an application give each element of an image array an ARBITRARY unit
+        // (glUniform1i per element). ES has no such call at all - "ES image units come
+        // exclusively from the layout(binding=N) qualifier" - and one declaration carries one
+        // binding, so ESSL nails an array's elements to the CONSECUTIVE units N, N+1, N+2, ...
+        // MobileGL used to stamp element [0]'s unit as the binding and let the rest fall where
+        // they fell: KHR-GL4x.shader_image_load_store.advanced-sso-simple assigns 0,2,4,6 and
+        // 1,3,5,7, so its two programs actually addressed 0,1,2,3 and 1,2,3,4 - one layer got the
+        // wrong value and three were never written, with no GL error and no link log. The same
+        // defect for SAMPLER arrays was fixed API-side (SubscriptUniformNameForElement); an image
+        // array has no API side to fix, because ES makes glUniform1i on an image uniform an
+        // INVALID_OPERATION.
+        //
+        // Repaired by SPLITTING the array into one SCALAR image uniform per element, each with
+        // its own layout(binding = N), and rewriting `name[k]` to the scalar declared for
+        // element k. One declaration carries one binding, so one declaration per unit is the
+        // only spelling that reaches an arbitrary set of them.
+        //
+        // That rewrite needs every k in the emitted text to be a LITERAL, and it is:
+        // LegalizeResourceArrayIndexingForEssl has already folded or lowered every dynamic
+        // image-array subscript in the module, because ESSL forbids one outright ("image arrays
+        // indexed with non-constant expressions are forbidden in GLSL ES", Mesa 26.1.4 at
+        // ES 3.2, on a raw GLES probe with no MobileGL in the loop). The earlier shape here -
+        // widening the array to cover the whole span of units and routing each subscript through
+        // a `const highp int` offset table - was written before that pass covered images, and
+        // the table lookup was itself one of the non-constant expressions the same probe refuses.
+        // The split also costs exactly the image uniforms the application declared, where the
+        // widening cost the whole SPAN (seven for the four elements of
+        // KHR-GL42.shader_image_load_store.advanced-sso-simple), so there is no budget for it to
+        // fail to fit in.
+        //
+        // Declines - leaving the array exactly as it was, and naming it in `outDeclined` for the
+        // caller to report - when the emitted extent disagrees with the reflection, when the
+        // array is reached by anything other than a subscript, or when a subscript is not a
+        // literal element index. Silence was the whole defect here, so a decline must be audible.
+        //
+        // Must run AFTER RebindImageUniformsToFrontendUnits and BakeImageFormatQualifiers (both
+        // key on the GL uniform name and on a binding already being stamped) and BEFORE
+        // SplitReadWriteImageUniforms (so each element that is both read and written is split
+        // with its own binding already on it) and RemoveLayoutBinding (which is what preserves
+        // image bindings). Like them, it is downstream of the L2 shader-translation memo, so the
+        // per-program units it reads need no entry in BuildEsslTranslationKey.
+        String RemapImageArrayElementUnits(const String& glslCode, const Vector<ImageArrayUnitPlan>& plans,
+                                           Vector<String>* outDeclined = nullptr);
+        // The member list of a `gl_PerVertex { ... }` redeclaration in already-emitted ESSL -
+        // the text between the braces, verbatim - or nullopt when the shader does not redeclare
+        // the block in that direction. `input` selects the `in gl_PerVertex` form over the
+        // `out` one.
+        //
+        // Exists so BuildPassthroughTessControlEssl can MIRROR the stages it has to sit between
+        // rather than guess at them. Whether SPIRV-Cross redeclares the built-in block, and with
+        // which members, depends on what the application's shader touched; a synthesized stage
+        // that redeclares a different shape than its neighbours is an ES link error against a
+        // program that has no other problem.
+        std::optional<String> ExtractPerVertexBlockMembers(const String& essl, Bool input);
+        // The pass-through tessellation control stage GL 4.6 core 11.2.2 describes: "the input
+        // patch is passed through unmodified", the output patch has PATCH_VERTICES vertices, and
+        // the levels come from the PATCH_DEFAULT_OUTER_LEVEL / PATCH_DEFAULT_INNER_LEVEL state.
+        //
+        // Desktop GL makes the control stage OPTIONAL. OpenGL ES 3.2 does not: it has no
+        // PATCH_DEFAULT_*_LEVEL state at all (only glPatchParameteri, for PATCH_VERTICES) and
+        // rejects a program that has an evaluation stage without a control stage - with an EMPTY
+        // info log, verified on an Adreno 830 with no MobileGL in the process. MobileGL's own
+        // frontend link succeeds, so the program reports GL_LINK_STATUS = TRUE, program 0 is
+        // bound in its place, and every draw silently renders nothing.
+        //
+        // `inPerVertexMembers` / `outPerVertexMembers` are the member lists to redeclare gl_in
+        // and gl_out with - normally taken from the neighbouring stages' own emitted ESSL via
+        // ExtractPerVertexBlockMembers, and empty to leave the driver's built-in declaration
+        // alone, which is what matching a neighbour that did not redeclare requires.
+        //
+        // All four outer levels and both inner levels are written unconditionally: writing a
+        // level the evaluation stage's domain does not use is legal and ignored, and it saves
+        // this from having to know the domain. They are literal 1.0 because that is the GL
+        // default and glPatchParameterfv - their only setter - is a stub in this frontend
+        // (MG_Impl/GLImpl/Exporting/Definitions.cpp). Implementing that entry point means making
+        // the levels a parameter here AND part of what makes a built program stale, exactly as
+        // PATCH_VERTICES already is; the two must move together, so they are named together.
+        //
+        // The same stage, for the same reason, that DirectVulkan synthesizes in
+        // ProgramFactory::BuildPassthroughTessControlSource - Vulkan likewise requires both
+        // tessellation stages. Kept as two generators rather than one because the two targets
+        // disagree on everything but the algorithm: desktop GLSL 450 against ESSL, a fixed
+        // gl_PerVertex shape that Vulkan matches structurally against a mirrored one, and a
+        // VkShaderModule against a driver shader object.
+        String BuildPassthroughTessControlEssl(Uint esslVersion, Uint patchVertices,
+                                               const String& inPerVertexMembers,
+                                               const String& outPerVertexMembers);
         // Prefix of the writeonly half a read+write image uniform is split into (see
-        // SplitReadWriteImageUniforms); the suffix is the image's own name.
+        // SplitReadWriteImageUniforms); the suffix is the image's own (already access-tagged) name.
         constexpr const char* IMAGE_WRITE_ALIAS_PREFIX = "mg_imageWrite_";
+        // The three names SplitReadWriteImageUniforms renames a rewritten image declaration
+        // under, one per REPAIR it can apply. Which one a stage picks is decided by that stage's
+        // own accesses, so two stages that use an image the same way arrive at the SAME name and
+        // two that use it differently arrive at different ones - which is exactly the property
+        // the rename exists for, at no cost to the stages that agree. Exposed for the tests.
+        constexpr const char* IMAGE_READONLY_ALIAS_PREFIX = "mg_imageRo_";
+        constexpr const char* IMAGE_WRITEONLY_ALIAS_PREFIX = "mg_imageWo_";
+        constexpr const char* IMAGE_SPLIT_READ_ALIAS_PREFIX = "mg_imageRw_";
         // ESSL refuses an image variable that carries a format qualifier other than r32f /
         // r32i / r32ui unless it also carries `readonly` or `writeonly` (GLSL ES 3.10 4.9 /
         // 3.20 4.10; glslang enforces it verbatim in ParseHelper.cpp's layoutObjectCheck).
@@ -152,15 +405,74 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // bare declaration, so the frontend raises no error and the illegal ESSL only shows
         // up as a device compile failure - and then as a silently no-op draw.
         //
-        // Restores a legal declaration:
-        //  * loaded only            -> add `readonly`
-        //  * stored only            -> add `writeonly`
+        // Restores a legal declaration, and RENAMES it after the repair it applied while doing so:
+        //  * loaded only            -> add `readonly`, rename under IMAGE_READONLY_ALIAS_PREFIX
+        //  * stored only            -> add `writeonly`, rename under IMAGE_WRITEONLY_ALIAS_PREFIX
         //  * both                   -> emit TWO declarations on the same binding and of the
-        //                              same type, `readonly <name>` and `writeonly
-        //                              <IMAGE_WRITE_ALIAS_PREFIX><name>`, and point every
-        //                              imageStore at the second one. Several image variables
-        //                              may share an image unit as long as they have the same
-        //                              type and format, which is exactly what the pair is.
+        //                              same type, `coherent readonly
+        //                              <IMAGE_SPLIT_READ_ALIAS_PREFIX><name>` and `coherent
+        //                              writeonly <IMAGE_WRITE_ALIAS_PREFIX><that name>`, point
+        //                              every imageStore at the second one, and follow each of
+        //                              those stores with `memoryBarrierImage();`. Several image
+        //                              variables may share an image unit as long as they have
+        //                              the same type and format, which is exactly what the pair
+        //                              is.
+        //
+        // The rename is the other half of the repair and applies to all three cases. The qualifier
+        // chosen above is a decision about ONE STAGE's accesses, and GLSL requires a uniform
+        // declared in two stages to be declared identically - so a shader that stores an image from
+        // the vertex stage and loads it from the fragment stage came out of here `writeonly` in one
+        // and `readonly` in the other. Adreno merges the two same-named declarations and silently
+        // drops the vertex-stage STORES: no GL error, no link log, LINK_STATUS = 1, and the image
+        // still reads back its initial contents
+        // (KHR-GL4x.shader_image_load_store.advanced-memory-dependentInvocation; a raw-ES probe
+        // isolated the trigger to the same-name/mismatched-qualifier pair, and only when both
+        // carry `coherent`). Renaming leaves no cross-stage variable to merge.
+        //
+        // The name is keyed on the REPAIR, not on the stage, and that distinction is the whole
+        // point: two stages that use an image the same way emit byte-identical declarations, so
+        // letting them keep one shared name costs nothing and merging them is correct, while two
+        // stages that use it differently land on different prefixes and cannot be merged at all.
+        // A per-STAGE tag also satisfied the first requirement but violated the second: it made
+        // the SAME image a distinct uniform in every stage that named it, and Adreno allocates
+        // image LOCATIONS per distinct uniform. KHR-GL43.shading_language_420pack.
+        // binding_images_texture_type_* declares three read+write images in each of its five
+        // stages; merged that is 6 image uniforms, per-stage-tagged it is 30, and the Adreno 830
+        // linker answered "Error: Image Image location or component exceeds max allowed. Error:
+        // Linking failed." - which, the frontend having already published LINK_STATUS = TRUE from
+        // glslang's link, surfaced only as every draw silently doing nothing and the images
+        // reading back zero. Mali and Mesa link the same text, so nothing but a device gate
+        // catches this.
+        //
+        // A declaration SPIRV-Cross already tagged `readonly` or `writeonly` needs no qualifier
+        // repair, but it is NOT stage-independent: that tag is derived from the accesses of the
+        // stage being emitted, so an image stored in the vertex stage and loaded in the fragment
+        // stage arrives here as `coherent writeonly g_image` and `coherent readonly g_image` -
+        // one name, two spellings, which is exactly the pair Adreno merges. Those declarations
+        // are therefore renamed too, keyed on the qualifier they already carry (readonly ->
+        // IMAGE_READONLY_ALIAS_PREFIX, writeonly -> IMAGE_WRITEONLY_ALIAS_PREFIX) and with
+        // nothing but the identifier changed. Stages that agree still reach the same alias and
+        // stay merged, so this costs no shader an extra image uniform.
+        //
+        // The declarations this pass still leaves untouched keep their names: one carrying BOTH
+        // readonly and writeonly (a spelling no access analysis produces, so it came from the
+        // application and is identical everywhere), and one carrying NEITHER, which is legal only
+        // for the r32f/r32i/r32ui formats and is likewise spelled the same in every stage.
+        //
+        // The `coherent` on both halves of the pair is load-bearing, not decoration: GLSL only
+        // guarantees a write through one image variable is visible to a read through a DIFFERENT
+        // one when both are coherent, and the split is what makes a same-variable
+        // read-after-write cross-variable. The single-declaration repairs above do not get it -
+        // nothing aliases them.
+        //
+        // The barrier is the other half of the same problem, and coherent alone did not cover it:
+        // visibility is not ORDER. Within one invocation the ES compiler sees a write to one
+        // variable and a read of another it has no reason to believe alias, and is free to serve
+        // the read from before the write - which is what advanced-memory-order's store/load/
+        // compare loop measured on Adreno. memoryBarrierImage() orders exactly those two, is core
+        // GLSL ES 3.10 in every stage, and is not an execution barrier, so it is legal in
+        // non-uniform control flow. It costs something in a shader that stores to a read+write
+        // image in a loop, which is why it is confined to the split pair.
         //
         // Budget note: the split DOUBLES the image-uniform count of the stage it fires in, so
         // a driver advertising a tight GL_MAX_{FRAGMENT,VERTEX,...}_IMAGE_UNIFORMS can turn a
@@ -170,8 +482,14 @@ namespace MobileGL::MG_Backend::DirectGLES {
         //
         // Runs on the transpiled ESSL, so it must see the bindings the frontend units were
         // already rewritten to and must run before those bindings are stripped - see the call
-        // site in Managers.cpp.
-        String SplitReadWriteImageUniforms(const String& glslCode);
+        // site in Managers.cpp. Its output is a function of the emitted text alone - it needs no
+        // stage and no per-program state - so it adds nothing to BuildEsslTranslationKey either.
+        //
+        // `outSplitCount`, when given, receives the number of declarations that were actually
+        // doubled - i.e. exactly how many image uniforms this stage gained over what the
+        // application declared. Zero for every shader but a handful, and the only number the
+        // budget note above can be reported with.
+        String SplitReadWriteImageUniforms(const String& glslCode, Uint* outSplitCount = nullptr);
         // Prefix of the per-sampler float uniform that carries GL_TEXTURE_LOD_BIAS into
         // the shader (see EmulateTextureLodBias); the suffix is the sampler's own name.
         constexpr const char* LOD_BIAS_UNIFORM_PREFIX = "mg_lodBias_";

MobileGL/MG_Backend/DirectVulkan/BackendObject_DirectVulkan.cpp

@@ -9,7 +9,9 @@
 #include "BackendObject_DirectVulkan.h"
 #include "MG_Backend/BackendObject.h"
 #include "DirectVulkan.h"
+#include "SubgroupSupportPolicy.h"
 #include "MG_State/GLState/FramebufferState/FramebufferObject.h"
+#include "MG_State/GLState/Core.h"
 #include "MG_State/GLState/TextureState/TextureState.h"
 #include "MG_Util/Classifiers/TextureEnumClassifier.h"
 #include "MG_Util/Converters/MGToGL/TextureEnumConverter.h"
@@ -383,6 +385,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
         UpdateDynamicBackendParameters();
         UpdateAdvertisedExtensions();
+        if (MG_State::pGLContext) {
+            MG_State::pGLContext->InvalidateCompileEnv();
+        }
         PopulateFormatCapabilities(physicalDevice.handle, vkGetPhysicalDeviceFormatProperties, m_vulkanCaps,
                                    MutableFormatCapabilities());
         PrintFormatCapabilities(GetFormatCapabilities());
@@ -497,20 +502,22 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             .ExtraVendor = Nullopt,
             .RendererGLInfo = {.TargetGLVersion = {4, 0, 0},
                                .TargetGLSLVersion = {4, 6, 0},
-                               // Baseline advertisement (no shader subgroup, no timer queries); a
-                               // live backend reconciles its copy in UpdateAdvertisedExtensions.
-                               .Extensions = BuildAdvertisedExtensions(false, false, false),
+                               // Baseline advertisement (no runtime-gated capabilities); a live
+                               // backend reconciles its copy in UpdateAdvertisedExtensions.
+                               .Extensions = BuildAdvertisedExtensions(false, false, false, false),
                                .IsCompatibilityProfile = false},
             .StaticBackendCapability = {.AllowVSOnlyPrograms = false}};
         return rendererInfo;
     }
 
     Vector<GLExtension> BuildAdvertisedExtensions(Bool shaderSubgroupSupported, Bool timerQueriesSupported,
-                                                  Bool anisotropicFilteringSupported) {
+                                                  Bool anisotropicFilteringSupported,
+                                                  Bool nonZeroIndirectBaseInstanceSupported) {
         Vector<GLExtension> extensions = {
             V_OpenGL30, V_OpenGL31, V_OpenGL32, V_OpenGL33, V_OpenGL40, E_GL_ARB_draw_buffers_blend,
             E_GL_ARB_compute_shader, E_GL_ARB_shader_storage_buffer_object, E_GL_ARB_shader_image_load_store,
-            E_GL_ARB_program_interface_query, E_GL_ARB_framebuffer_object, E_GL_ARB_multi_draw_indirect,
+            E_GL_ARB_clear_buffer_object, E_GL_ARB_program_interface_query, E_GL_ARB_framebuffer_object, E_GL_ARB_draw_indirect,
+            E_GL_ARB_multi_draw_indirect,
             E_GL_ARB_indirect_parameters, E_GL_EXT_framebuffer_object, E_GL_ARB_depth_texture, E_GL_ARB_buffer_storage,
             E_GL_ARB_texture_storage, E_GL_ARB_texture_storage_multisample, E_GL_ARB_texture_multisample,
             E_GL_ARB_clear_texture, E_GL_ARB_direct_state_access, E_GL_ARB_shader_draw_parameters,
@@ -530,6 +537,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // extension explicitly permits. It is also the only thing that
             // exposes glProgramParameteri before GL 4.1.
             E_GL_ARB_get_program_binary};
+        // Vulkan's drawIndirectFirstInstance feature is optional. Direct base-instance calls work
+        // without it, but ARB_base_instance also promises non-zero firstInstance in GPU indirect
+        // commands; the renderer supplies true only when that word is legal and gl_InstanceID can
+        // be rebased to OpenGL's zero-based semantics.
+        if (nonZeroIndirectBaseInstanceSupported) {
+            extensions.push_back(E_GL_ARB_base_instance);
+        }
         if (shaderSubgroupSupported && !MG_Config::Features.DisableSubgroup) {
             extensions.push_back(E_GL_KHR_shader_subgroup);
         }
@@ -548,12 +562,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         if (MG_Util::Async::AsyncShaderCompileEnabled()) {
             extensions.push_back(E_GL_KHR_parallel_shader_compile);
         }
-        // GL_ARB_gpu_shader_fp64 is opt-in (MOBILEGL_ADVERTISE_FP64). Every `double` in a
-        // shader compiles and runs already - it is narrowed to 32 bits before the module
-        // reaches this backend - so an application that simply uses doubles needs nothing
-        // advertised. What the extension additionally promises is 64-bit PRECISION, which no
-        // mobile GPU has and the narrowing cannot fake, so advertising it by default would
-        // make an application that checks the string take a path MobileGL cannot honour.
+        // GL_ARB_gpu_shader_fp64 is opt-in (MOBILEGL_ADVERTISE_FP64), and stays opt-in even on a
+        // device that HAS shaderFloat64. Every `double` in a shader compiles and runs either way
+        // - narrowed to 32 bits where the device has no 64-bit floats, kept whole where it does -
+        // so an application that simply uses doubles needs nothing advertised. What the extension
+        // additionally promises is the whole GL_ARB_gpu_shader_fp64 SURFACE (glUniform*d
+        // conformance, the fp64 built-ins, the state queries), and turning the string on is a
+        // decision about all of it rather than about the shader path alone.
         if (MG_Config::Features.AdvertiseFp64) {
             extensions.push_back(E_GL_ARB_gpu_shader_fp64);
         }
@@ -678,6 +693,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         m_vulkanCaps = capabilities;
         UpdateDynamicBackendParameters();
         UpdateAdvertisedExtensions();
+        if (MG_State::pGLContext) {
+            MG_State::pGLContext->InvalidateCompileEnv();
+        }
         MutableFormatCapabilities().Clear();
     }
 
@@ -688,9 +706,16 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // real device timestamp support. ApplyVulkanCapabilitiesForTesting may
         // run without a renderer; no timer query is advertised then. Rebuilding
         // the whole list keeps re-runs idempotent.
+        // The opt-in emulated compute path (SubgroupSupportPolicy.h) carries the
+        // extension by itself on devices with no native subgroup support at all; a
+        // device with native subgroups always advertises - and uses - those.
+        const Bool subgroupSupportAdvertised =
+            m_vulkanCaps.SupportsShaderSubgroup ||
+            ShouldEmulateSubgroups(m_vulkanCaps.SupportsShaderSubgroup);
         m_rendererInfo.RendererGLInfo.Extensions = BuildAdvertisedExtensions(
-            m_vulkanCaps.SupportsShaderSubgroup, pVulkanRenderer && pVulkanRenderer->IsTimerQuerySupported(),
-            pVulkanRenderer && pVulkanRenderer->IsSamplerAnisotropySupported());
+            subgroupSupportAdvertised, pVulkanRenderer && pVulkanRenderer->IsTimerQuerySupported(),
+            pVulkanRenderer && pVulkanRenderer->IsSamplerAnisotropySupported(),
+            pVulkanRenderer && pVulkanRenderer->IsNonZeroIndirectBaseInstanceSupported());
     }
 
     void BackendObject_DirectVulkan::UpdateDynamicBackendParameters() {
@@ -823,6 +848,38 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         m_dynamicParameters.MaxShaderStorageBufferBindings =
             clampLimit("GL_MAX_SHADER_STORAGE_BUFFER_BINDINGS", m_vulkanCaps.MaxShaderStorageBufferBindings,
                        kMaxAdvertisedBufferBlocks);
+        // Per-stage GL_MAX_*_SHADER_STORAGE_BLOCKS. Vulkan has one descriptor limit for every
+        // stage (maxPerStageDescriptorStorageBuffers, which is what MaxComputeShaderStorageBlocks
+        // carries), so the stage limits differ only by whether the stage can have blocks at all.
+        //
+        // Deliberately NOT gated on vertexPipelineStoresAndAtomics, unlike the per-stage image
+        // uniforms below. That gate reads as the obvious one and is wrong here in practice: a
+        // Mali-G925-Immortalis reports vertexPipelineStoresAndAtomics=false (supported AND
+        // enabled) and yet runs all 433 KHR-GL43.constant_expressions.*_tess_* cases correctly
+        // through this backend - those write their result through a storage block declared in a
+        // tessellation stage. Gating would report 0 and turn 433 passing cases into
+        // "unsupported", removing function that demonstrably works.
+        //
+        // The asymmetry with DirectGLES is real and is the point. There, 0 prevents a program
+        // the driver refuses outright at link time; the honest limit converts a silent
+        // wrong-render into a capability an application can route around. Here there is no such
+        // failure to prevent, so the limit stays at what the device can address. If a Vulkan
+        // device is ever found that genuinely rejects such a pipeline, the gate belongs at
+        // pipeline creation where the rejection is observable, not on a feature bit this driver
+        // reports inaccurately.
+        {
+            const Int maxPerStageStorageBlocks =
+                std::min(std::max(m_dynamicParameters.MaxComputeShaderStorageBlocks, 0),
+                         std::min(std::max(m_dynamicParameters.MaxCombinedShaderStorageBlocks, 0),
+                                  std::max(m_dynamicParameters.MaxShaderStorageBufferBindings, 0)));
+            m_dynamicParameters.MaxVertexShaderStorageBlocks = maxPerStageStorageBlocks;
+            m_dynamicParameters.MaxTessControlShaderStorageBlocks = maxPerStageStorageBlocks;
+            m_dynamicParameters.MaxTessEvaluationShaderStorageBlocks = maxPerStageStorageBlocks;
+            // The one hard capability in the set: no geometry stage means no blocks in it.
+            m_dynamicParameters.MaxGeometryShaderStorageBlocks =
+                m_vulkanCaps.SupportsGeometryShader ? maxPerStageStorageBlocks : 0;
+            m_dynamicParameters.MaxFragmentShaderStorageBlocks = maxPerStageStorageBlocks;
+        }
         m_dynamicParameters.MaxTextureBufferSize = clampLimit(
             "GL_MAX_TEXTURE_BUFFER_SIZE", m_vulkanCaps.MaxTextureBufferSize, kMaxAdvertisedTextureBufferSize);
         m_dynamicParameters.TextureBufferOffsetAlignment = m_vulkanCaps.TextureBufferOffsetAlignment;
@@ -849,8 +906,22 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const Int maxSupportedDrawBuffers = static_cast<Int>(MG_State::GLState::FramebufferObject::MAX_DRAW_BUFFERS);
         m_dynamicParameters.MaxDrawBuffers = std::min(m_vulkanCaps.MaxDrawBuffers, maxSupportedDrawBuffers);
         m_dynamicParameters.MaxColorAttachments = std::min(m_vulkanCaps.MaxColorAttachments, maxSupportedDrawBuffers);
-        m_dynamicParameters.MaxClipDistances = m_vulkanCaps.MaxClipDistances;
+        // Same shape as the image-uniform limits three lines above: maxClipDistances is reported
+        // by every device, but declaring ClipDistance in a module needs the shaderClipDistance
+        // FEATURE, which VulkanRenderer enables exactly where the physical device has it. Without
+        // it the limit describes a capacity no shader may use, so report none.
+        m_dynamicParameters.MaxClipDistances =
+            m_vulkanCaps.SupportsShaderClipDistance ? std::max(m_vulkanCaps.MaxClipDistances, 0) : 0;
         m_dynamicParameters.MaxViewports = m_vulkanCaps.MaxViewports;
+        // Assigned explicitly rather than left to the struct's defaults, like every other
+        // parameter here, so a second fill cannot inherit a stale value. GL_UNDEFINED_VERTEX is
+        // the truthful answer for DirectVulkan and a legal one (GL 4.6 table 23.65): which vertex
+        // provokes is chosen per pipeline by VulkanRenderer::SelectProvokingVertexMode out of
+        // VK_EXT_provoking_vertex, provokingVertexModePerPipeline and the topology, so there is no
+        // one convention to name. Vulkan's own default is FIRST, which is the opposite of the
+        // GL_LAST_VERTEX_CONVENTION this used to claim unconditionally.
+        m_dynamicParameters.LayerProvokingVertex = GL_UNDEFINED_VERTEX;
+        m_dynamicParameters.ViewportIndexProvokingVertex = GL_UNDEFINED_VERTEX;
         m_dynamicParameters.MaxViewportWidth = m_vulkanCaps.MaxViewportWidth;
         m_dynamicParameters.MaxViewportHeight = m_vulkanCaps.MaxViewportHeight;
         m_dynamicParameters.ViewportBoundsRangeMin = m_vulkanCaps.ViewportBoundsRangeMin;
@@ -895,26 +966,34 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     DynParams::PerLayerFramebufferAttachmentBit(TextureTarget::TextureCubeMapArray);
             }
         }
-        // Never, on any device, and no longer for the reason it used to be. It used to track
-        // shaderFloat64 because a `dvec3` input needed the Float64 capability to exist in the
-        // module at all; a 64-bit vertex FETCH was already impossible (VK_FORMAT_R64*_SFLOAT is
-        // optional and lavapipe reports zero bufferFeatures for all four), so the attribute
-        // arrived as its 32-bit word pair and PackDoubleVertexInputsPass bitcast it back.
+        // The device feature the whole fp64 story hangs off. With it, a module keeps its
+        // OpCapability Float64 and real doubles reach the driver; without it the transpile
+        // narrows every 64-bit float to 32 (ShaderTranspiler::DemoteFloat64Pass), because
+        // VUID-VkShaderModuleCreateInfo-pCode-08740 forbids the capability outright and no
+        // pipeline could be built from such a module. lavapipe reports it; Adreno and Mali both
+        // report VK_FALSE, so on every real mobile device this is false and the demotion runs
+        // exactly as it always has.
+        m_dynamicParameters.SupportsShaderFloat64 = m_vulkanCaps.SupportsShaderFloat64;
+        // Never, on any device, and DELIBERATELY NOT COUPLED to the line above even though it
+        // once tracked the same feature. It used to, because a `dvec` input needed Float64 to
+        // exist in the module at all; a 64-bit vertex FETCH was already impossible
+        // (VK_FORMAT_R64*_SFLOAT is optional and lavapipe reports zero bufferFeatures for all
+        // four), so the attribute arrived as its 32-bit word pair and PackDoubleVertexInputsPass
+        // bitcast it back.
         //
-        // The shader half of that is gone: every 64-bit float is narrowed before any module
-        // reaches a backend (ShaderTranspiler::DemoteFloat64Pass), so there is no `double` input
-        // left to bitcast INTO, and feeding a UINT-formatted attribute to what is now a `float`
-        // input would be silent garbage. Reconstructing the value would mean decoding the
-        // IEEE-754 double bit pattern in the shader - software fp64, which is precisely what the
-        // demotion exists to avoid - and on Espryt it would additionally need the ES driver to
-        // fetch 2N uint components where the application declared N doubles, which a dvec3 or
-        // dvec4 cannot even express within one attribute location.
+        // Re-coupling it does not work, and the reason is worth recording because it is not
+        // obvious: this flag decides the VkFormat from the VAO ATTRIBUTE alone, and the attribute
+        // does not know what the shader declared. glVertexAttribFormat(GL_DOUBLE) against a plain
+        // `in vec4` is not only legal but the common case
+        // (KHR-GL43.vertex_attrib_binding.basic-input-case4 does exactly that, and case5 adds
+        // normalized=GL_TRUE), and advanced-bindingUpdate feeds a dvec3 the same way - GL defines
+        // all of them as "doubles in memory, converted to float". Turning the flag on turns the
+        // narrowing OFF for every one of them and the attributes come back unfetched.
         //
-        // So glVertexAttribLFormat / glVertexAttribLPointer are declined here exactly as they
-        // already were on Espryt and on every real mobile device (Adreno and Mali both report
-        // shaderFloat64 == VK_FALSE), and for the same visible reason. A `dvec3` INPUT still
-        // compiles and draws - it is a `vec3` after demotion - as long as the application feeds
-        // it with glVertexAttribPointer(GL_FLOAT) rather than 64-bit data.
+        // What keeps the two halves honest instead is a per-MODULE decision: a vertex module that
+        // declares a 64-bit float INPUT is demoted whole, even where the backend has native fp64,
+        // so `dvec` inputs are `vec` inputs on this backend exactly as they always were. See
+        // ShaderCompiler::SanitizeAndOptimizeBinary.
         m_dynamicParameters.SupportsFloat64VertexAttributes = false;
         m_dynamicParameters.MaxShaderStorageBlockSize =
             std::min(m_vulkanCaps.MaxShaderStorageBlockSize, kMaxAdvertisedShaderStorageBlockSize);
@@ -924,6 +1003,18 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             m_dynamicParameters.SubgroupSupportedFeatures =
                 mapSubgroupFeatures(m_vulkanCaps.SubgroupSupportedOperations);
             m_dynamicParameters.SubgroupQuadOperationsInAllStages = m_vulkanCaps.SubgroupQuadOperationsInAllStages;
+        } else if (ShouldEmulateSubgroups(m_vulkanCaps.SupportsShaderSubgroup)) {
+            // MOBILEGL_MAGMA_EMULATE_SUBGROUP on a device with no native subgroups: the
+            // advertised values describe the 32-lane virtual subgroup the compute
+            // lowering implements (SubgroupSupportPolicy.h / EmulateSubgroupsPass).
+            // GL requires the advertisement and the execution to agree, and on this
+            // path the emulation is what executes; only the compute stage is offered.
+            m_dynamicParameters.SubgroupSize = kEmulatedSubgroupSize;
+            m_dynamicParameters.SubgroupSupportedStages = kEmulatedSubgroupStages;
+            m_dynamicParameters.SubgroupSupportedFeatures = kEmulatedSubgroupFeatures;
+            m_dynamicParameters.SubgroupQuadOperationsInAllStages = false;
+            MGLOG_I("DirectVulkan: emulating 32-lane compute subgroups "
+                    "(MOBILEGL_MAGMA_EMULATE_SUBGROUP, no native subgroup support)");
         } else {
             m_dynamicParameters.SubgroupSize = 0;
             m_dynamicParameters.SubgroupSupportedStages = 0;

MobileGL/MG_Backend/DirectVulkan/BackendObject_DirectVulkan.h

@@ -62,8 +62,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     // POST screen shows.
 
     // Static identity of the Magma renderer (renderer/backend names, target GL/GLSL
-    // versions, ExtraVendor) with the baseline extension advertisement (no shader
-    // subgroup, no timer queries). A live backend copies this in its constructor and
+    // versions, ExtraVendor) with the baseline extension advertisement (no runtime-gated
+    // capabilities). A live backend copies this in its constructor and
     // reconciles the Extensions in UpdateAdvertisedExtensions once real capabilities
     // exist; callers that need the advertised list for a known capability set must
     // use BuildAdvertisedExtensions instead.
@@ -74,7 +74,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     // MOBILEGL_DISABLE_TIMERQUERY escape hatches are applied inside, so callers pass
     // the detected device support (passing an already-gated value is harmless).
     Vector<GLExtension> BuildAdvertisedExtensions(Bool shaderSubgroupSupported, Bool timerQueriesSupported,
-                                                  Bool anisotropicFilteringSupported);
+                                                  Bool anisotropicFilteringSupported,
+                                                  Bool nonZeroIndirectBaseInstanceSupported);
 
     // Format: <GPU Name>, Vulkan <Vulkan Version>, Driver <Driver Version> — the exact
     // string an initialized backend returns from GetBackendAPIVersionString (and that

MobileGL/MG_Backend/DirectVulkan/DirectVulkan.cpp

@@ -69,6 +69,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // slot's ownership unambiguous.
             Uint64 programLifetimeId = 0;
             Uint32 backendStateVersion = 0;
+            // glShaderStorageBlockBinding deliberately does NOT bump the backend state
+            // version, and the pipeline composite is unnamed so the in-place patch in
+            // DirectVulkan::ShaderStorageBlockBinding can never reach its slot - the
+            // mirror replay bumps only the program's block-binding version. Without this
+            // key the composite's slot kept serving the pre-rebind block.binding.
+            Uint32 blockBindingVersion = 0;
             Vector<StorageBlockResource> storageBlocks;
             Vector<BufferVariableResource> bufferVariables;
             GLint computeWorkGroupSize[3] = {1, 1, 1};
@@ -156,18 +162,33 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             auto& cache = g_programResourceCaches[program.GetExternalIndex()];
             const Uint64 programLifetimeId = program.GetLifetimeId();
             const Uint32 backendStateVersion = program.GetBackendStateVersion();
+            const Uint32 blockBindingVersion = program.GetBlockBindingVersion();
             // The lifetime id must match too: a new program that reuses a deleted
             // program's name and happens to land on the same backendStateVersion (both
             // count from zero) would otherwise be served the dead program's reflection.
             if (cache.programLifetimeId == programLifetimeId &&
                 cache.backendStateVersion == backendStateVersion &&
                 (!cache.storageBlocks.empty() || !cache.bufferVariables.empty())) {
+                if (cache.blockBindingVersion != blockBindingVersion) {
+                    // Only the block bindings moved (glShaderStorageBlockBinding, or the
+                    // pipeline composite's mirror replay - neither touches the backend
+                    // state version): the reflection itself is unchanged, so re-apply the
+                    // overrides by name instead of re-running spirv-reflect. Overrides
+                    // only ever accumulate, so a block without one still holds its
+                    // declared binding.
+                    for (auto& block : cache.storageBlocks) {
+                        const Int rebound = program.GetShaderStorageBlockBindingOverride(block.name);
+                        if (rebound >= 0) block.binding = static_cast<Uint32>(rebound);
+                    }
+                    cache.blockBindingVersion = blockBindingVersion;
+                }
                 return cache;
             }
 
             cache = {};
             cache.programLifetimeId = programLifetimeId;
             cache.backendStateVersion = backendStateVersion;
+            cache.blockBindingVersion = blockBindingVersion;
 
             Vector<SpvReflectShaderModule> modules;
             Vector<Bool> validModules;
@@ -269,14 +290,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 drawBuffer->SyncPersistentMappedRange();
                 const SizeT commandOffset = reinterpret_cast<SizeT>(indirect);
                 if (drawBuffer->MappedData() == nullptr || commandOffset + requiredBytes > drawBuffer->GetSize()) {
-                    MGLOG_E("%s skipped: invalid GL_DRAW_INDIRECT_BUFFER binding or range", label);
+                    MGLOG_E_ONCE("%s skipped: invalid GL_DRAW_INDIRECT_BUFFER binding or range", label);
                     return nullptr;
                 }
                 return drawBuffer->MappedData() + commandOffset;
             }
 
             if (!indirect) {
-                MGLOG_E("%s skipped: indirect pointer is null", label);
+                MGLOG_E_ONCE("%s skipped: indirect pointer is null", label);
                 return nullptr;
             }
 
@@ -398,7 +419,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             stride = sizeof(DrawArraysIndirectCommand);
         }
         if (stride < static_cast<GLsizei>(sizeof(DrawArraysIndirectCommand))) {
-            MGLOG_E("MultiDrawArraysIndirect skipped: stride %d is smaller than command size %zu",
+            MGLOG_E_ONCE("MultiDrawArraysIndirect skipped: stride %d is smaller than command size %zu",
                     stride, sizeof(DrawArraysIndirectCommand));
             return;
         }
@@ -446,20 +467,20 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             stride = sizeof(DrawArraysIndirectCommand);
         }
         if (stride < static_cast<GLsizei>(sizeof(DrawArraysIndirectCommand))) {
-            MGLOG_E("MultiDrawArraysIndirectCount skipped: stride %d is smaller than command size %zu",
+            MGLOG_E_ONCE("MultiDrawArraysIndirectCount skipped: stride %d is smaller than command size %zu",
                     stride, sizeof(DrawArraysIndirectCommand));
             return;
         }
 
         auto parameterBuffer = MG_State::pGLContext->GetBufferBindingSlot(BufferTarget::Parameter).GetBoundObject();
         if (!parameterBuffer || drawcount < 0 || static_cast<SizeT>(drawcount) + sizeof(Uint32) > parameterBuffer->GetSize()) {
-            MGLOG_E("MultiDrawArraysIndirectCount skipped: invalid GL_PARAMETER_BUFFER binding or range");
+            MGLOG_E_ONCE("MultiDrawArraysIndirectCount skipped: invalid GL_PARAMETER_BUFFER binding or range");
             return;
         }
 
         parameterBuffer->SyncPersistentMappedRange();
         if (parameterBuffer->MappedData() == nullptr) {
-            MGLOG_E("MultiDrawArraysIndirectCount skipped: CPU fallback cannot read parameter buffer");
+            MGLOG_E_ONCE("MultiDrawArraysIndirectCount skipped: CPU fallback cannot read parameter buffer");
             return;
         }
 
@@ -513,7 +534,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         const SizeT indexSize = MG_Util::GetGLTypeSize(type);
         if (indexSize == 0) {
-            MGLOG_E("DrawElementsIndirect skipped: unsupported index type 0x%x", type);
+            MGLOG_E_ONCE("DrawElementsIndirect skipped: unsupported index type 0x%x", type);
             return;
         }
 
@@ -611,15 +632,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         MOBILEGL_ASSERT(MG_State::pGLContext, "DirectVulkan::CopyTexSubImage2D called with null GL context");
         pVulkanRenderer->CopyTexSubImage2D(target, level, xoffset, yoffset, x, y, width, height);
     }
-    void CopyImageSubData(const SharedPtr<MG_State::GLState::ITextureObject>& srcTexture,
+    void CopyImageSubData(const CopyImageEndpoint& src,
                           GLenum srcTarget, GLint srcLevel, GLint srcX, GLint srcY, GLint srcZ,
-                          const SharedPtr<MG_State::GLState::ITextureObject>& dstTexture,
+                          const CopyImageEndpoint& dst,
                           GLenum dstTarget, GLint dstLevel, GLint dstX, GLint dstY, GLint dstZ,
                           GLsizei srcWidth, GLsizei srcHeight, GLsizei srcDepth) {
         MOBILEGL_ASSERT(pVulkanRenderer, "DirectVulkan::CopyImageSubData called with null VulkanRenderer");
         MOBILEGL_ASSERT(MG_State::pGLContext, "DirectVulkan::CopyImageSubData called with null GL context");
-        pVulkanRenderer->CopyImageSubData(srcTexture, srcTarget, srcLevel, srcX, srcY, srcZ,
-                                          dstTexture, dstTarget, dstLevel, dstX, dstY, dstZ,
+        pVulkanRenderer->CopyImageSubData(src, srcTarget, srcLevel, srcX, srcY, srcZ,
+                                          dst, dstTarget, dstLevel, dstX, dstY, dstZ,
                                           srcWidth, srcHeight, srcDepth);
     }
     void GenerateMipmap(GLenum target) {
@@ -1009,7 +1030,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // shift - the hardware divide was the hottest instruction of this loop.
         const SizeT indexSize = MG_Util::GetGLTypeSize(type);
         if (indexSize == 0) {
-            MGLOG_E("MultiDrawElements skipped: unsupported index type 0x%x", type);
+            MGLOG_E_ONCE("MultiDrawElements skipped: unsupported index type 0x%x", type);
             return;
         }
         const Uint32 indexSizeShift = static_cast<Uint32>(std::countr_zero(indexSize));

MobileGL/MG_Backend/DirectVulkan/DirectVulkan.h

@@ -82,9 +82,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                         GLsizei height, GLint border);
     void CopyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width,
                            GLsizei height);
-    void CopyImageSubData(const SharedPtr<MG_State::GLState::ITextureObject>& srcTexture,
+    void CopyImageSubData(const CopyImageEndpoint& src,
                           GLenum srcTarget, GLint srcLevel, GLint srcX, GLint srcY, GLint srcZ,
-                          const SharedPtr<MG_State::GLState::ITextureObject>& dstTexture,
+                          const CopyImageEndpoint& dst,
                           GLenum dstTarget, GLint dstLevel, GLint dstX, GLint dstY, GLint dstZ,
                           GLsizei srcWidth, GLsizei srcHeight, GLsizei srcDepth);
     void GenerateMipmap(GLenum target);

MobileGL/MG_Backend/DirectVulkan/Renderer/FrameContext.cpp

@@ -205,7 +205,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // commands away. The device is gone on that path anyway - stay silent-safe
         // rather than trade a lost device for a barrier into a closed buffer.
         if (frame.hasCommandBufferRecorded) {
-            MGLOG_E("TransitionToPresent: command buffer already closed; skipping the present barrier");
+            MGLOG_E_ONCE("TransitionToPresent: command buffer already closed; skipping the present barrier");
             return false;
         }
 

MobileGL/MG_Backend/DirectVulkan/Renderer/PipelineFactory.cpp

@@ -206,6 +206,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         XXHASH_VERIFY(
             XXH64_update(m_hashState, &payload.primitiveRestartEnable, sizeof(payload.primitiveRestartEnable)));
         XXHASH_VERIFY(XXH64_update(m_hashState, &payload.patchControlPoints, sizeof(payload.patchControlPoints)));
+        XXHASH_VERIFY(XXH64_update(m_hashState, &payload.viewportCount, sizeof(payload.viewportCount)));
         XXHASH_VERIFY(XXH64_update(m_hashState, &payload.polygonMode, sizeof(payload.polygonMode)));
         XXHASH_VERIFY(XXH64_update(m_hashState, &payload.cullMode, sizeof(payload.cullMode)));
         XXHASH_VERIFY(XXH64_update(m_hashState, &payload.frontFace, sizeof(payload.frontFace)));
@@ -259,7 +260,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // is the correct price for a broken pipeline and is bounded by the draw itself being
         // skipped.
         if (pipeline == VK_NULL_HANDLE) {
-            MGLOG_I("PipelineFactory::GetOrCreatePipeline: creation failed for hash=0x%llx "
+            // Unlatched, like the CreatePipeline report it accompanies: a pipeline MobileGL
+            // assembled and the driver refused is a broken invariant, not an expected failure,
+            // so it stays loud for as long as it is reachable. Raised from MGLOG_I once the
+            // Log.h ordering fix made MGLOG_E live in INFO builds.
+            MGLOG_E("PipelineFactory::GetOrCreatePipeline: creation failed for hash=0x%llx "
                     "programHash=0x%llx; not caching the failure",
                     static_cast<unsigned long long>(hash),
                     static_cast<unsigned long long>(payload.programHash));
@@ -402,8 +407,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         tessellation.patchControlPoints = payload.patchControlPoints;
 
         VkPipelineViewportStateCreateInfo vpci{VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO};
-        vpci.viewportCount = 1;
-        vpci.scissorCount = 1;
+        // Both counts move together: GL has one scissor rectangle per viewport, and Vulkan
+        // requires viewportCount == scissorCount whenever both are dynamic
+        // (VUID-VkPipelineViewportStateCreateInfo-scissorCount-04136). The caller has already
+        // clamped this to the device's multiViewport capability.
+        vpci.viewportCount = std::max<Uint32>(payload.viewportCount, 1u);
+        vpci.scissorCount = vpci.viewportCount;
 
         VkPipelineRasterizationStateCreateInfo raster{VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO};
         raster.polygonMode = payload.polygonMode;
@@ -471,9 +480,56 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         blend.attachmentCount = payload.colorAttachmentCount;
         blend.pAttachments = colorAttachments.empty() ? nullptr : colorAttachments.data();
 
+        // A GL program may have a tessellation EVALUATION stage and no CONTROL stage: GL 4.6 core
+        // 11.2.2 gives it a fixed-function pass-through instead. Vulkan has no such stage, and
+        // VUID-VkGraphicsPipelineCreateInfo-pStages-00730 requires both tessellation stages or
+        // neither - so the renderer synthesizes the pass-through GL describes and hands it in
+        // here (see ProgramFactory::GetOrCreatePassthroughTessControlStage).
+        //
+        // The refusal below is what keeps the half-tessellated shape away from the driver when
+        // there is no synthesized stage to add - because Mali does not reject it, it dereferences
+        // null INSIDE vkCreateGraphicsPipelines and takes the process down (SIGSEGV, fault addr
+        // 0x34, on Mali-G715/r54p2 and Mali-G925/r49p1 alike; Adreno and lavapipe merely render
+        // wrong). Returning VK_NULL_HANDLE routes this through the same path a driver rejection
+        // takes: the draw is skipped, nothing is memoised, and the process survives.
+        const Vector<VkPipelineShaderStageCreateInfo>* effectiveStages = payload.stages;
+        Vector<VkPipelineShaderStageCreateInfo> stagesWithPassthrough;
+        if (payload.passthroughTessControlStage.module != VK_NULL_HANDLE) {
+            stagesWithPassthrough = *payload.stages;
+            stagesWithPassthrough.push_back(payload.passthroughTessControlStage);
+            effectiveStages = &stagesWithPassthrough;
+        }
+        {
+            VkShaderStageFlags stagesPresent = 0;
+            for (const auto& stageInfo : *effectiveStages) {
+                stagesPresent |= stageInfo.stage;
+            }
+            const Bool hasTessControl = (stagesPresent & VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT) != 0;
+            const Bool hasTessEval = (stagesPresent & VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT) != 0;
+            if (hasTessControl != hasTessEval) {
+                // Latched, and the latch is the point: a failed creation is deliberately never
+                // memoised (see GetOrCreatePipeline), so a program in this state re-enters here
+                // once per draw, every frame - and a refusal diagnostic that repeats per draw is
+                // noise, not a diagnostic. One line names the program; the draws it explains are
+                // all the same draw.
+                static Bool s_warnedHalfTessellatedPipeline = false;
+                if (!s_warnedHalfTessellatedPipeline) {
+                    s_warnedHalfTessellatedPipeline = true;
+                    MGLOG_E_ONCE("PipelineFactory::CreatePipeline: refusing a pipeline with %s tessellation stage and "
+                            "no %s stage (VUID-VkGraphicsPipelineCreateInfo-pStages-00730). programHash=0x%llx "
+                            "patchControlPoints=%u. Its draws are skipped; logged once.",
+                            hasTessEval ? "an evaluation" : "a control",
+                            hasTessEval ? "control" : "evaluation",
+                            static_cast<unsigned long long>(payload.programHash),
+                            payload.patchControlPoints);
+                }
+                return VK_NULL_HANDLE;
+            }
+        }
+
         VkGraphicsPipelineCreateInfo gpi{VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO};
-        gpi.stageCount = static_cast<Uint32>(payload.stages->size());
-        gpi.pStages = payload.stages->data();
+        gpi.stageCount = static_cast<Uint32>(effectiveStages->size());
+        gpi.pStages = effectiveStages->data();
         gpi.pVertexInputState = payload.vertexInputState;
         gpi.pInputAssemblyState = &ia;
         gpi.pTessellationState =
@@ -490,6 +546,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         VkPipeline pipeline = VK_NULL_HANDLE;
         const VkResult result = vkCreateGraphicsPipelines(m_device, m_pipelineCache, 1, &gpi, nullptr, &pipeline);
+        // Loud, at MGLOG_F, and deliberately NOT latched. vkCreateGraphicsPipelines refusing a
+        // pipeline MobileGL assembled is a should-never-happen state, and the driver's own
+        // answer is VK_ERROR_UNKNOWN - no information at all - so this dump is the entire
+        // diagnosis. It is not an expected failure mode, so the one-shot rule that quiets W/E
+        // does not apply: while this is reachable it should keep saying so on every draw.
+        // GetOrCreatePipeline deliberately does not cache the failure, which is what makes that
+        // repetition happen; if the repetition ever needs to stop, fix the pipeline, not the log.
         if (result != VK_SUCCESS) {
             MGLOG_F("PipelineFactory::CreatePipeline failed: result=%s (%d) programHash=0x%llx vertexInputHash=0x%llx stageCount=%u topology=%s(%d) colorAttachmentCount=%u samples=%s(%d) subpass=%u",
                     VkResultToString(result),
@@ -522,8 +585,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     payload.vertexInputState->vertexAttributeDescriptionCount);
             // The driver's own answer is VK_ERROR_UNKNOWN, i.e. no information at all, so the only
             // way to work out WHICH shader it choked on (the open sampler-array-in-struct
-            // investigation) is to name the modules. MGLOG_I, not _D/_E: this must survive in the
-            // INFO-level builds that CTS actually runs against.
+            // investigation) is to name the modules. MGLOG_I, not _D: this is part of a
+            // should-never-happen report and must survive in the INFO-level builds that CTS
+            // actually runs against, alongside the MGLOG_F lines above.
             if (payload.stageSpirvDigests) {
                 for (SizeT i = 0; i < payload.stageSpirvDigests->size(); ++i) {
                     const auto& digest = (*payload.stageSpirvDigests)[i];

MobileGL/MG_Backend/DirectVulkan/Renderer/PipelineFactory.h

@@ -42,6 +42,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             Bool primitiveRestartEnable = false;
             // GL_PATCH_VERTICES; only read for a PATCH_LIST topology.
             Uint32 patchControlPoints = 3;
+            // How many of ARB_viewport_array's viewports this pipeline rasterizes into. 1 for
+            // every program that never assigns gl_ViewportIndex, which is all of them outside the
+            // conformance suite - the wide shape costs a longer vkCmdSetViewport/Scissor per state
+            // change and can cost hardware fast paths, so it is opt-in per program. Baked into the
+            // pipeline (viewportCount is not dynamic without VK_EXT_extended_dynamic_state) and
+            // therefore hashed; the DYNAMIC viewport/scissor arrays the draw pushes must have
+            // exactly this many elements (VUID-vkCmdDraw-viewportCount-03417/-03418).
+            Uint32 viewportCount = 1;
             VkPolygonMode polygonMode = VK_POLYGON_MODE_FILL;
             VkCullModeFlags cullMode = VK_CULL_MODE_BACK_BIT;
             VkFrontFace frontFace = VK_FRONT_FACE_CLOCKWISE;
@@ -71,6 +79,17 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             Bool fragmentReplacesDepth = false;
             Array<VkPipelineColorBlendAttachmentState, kMaxColorAttachments> colorBlendAttachments{};
             const Vector<VkPipelineShaderStageCreateInfo>* stages = nullptr;
+            // The tessellation control stage this renderer synthesized for a program that has
+            // an evaluation stage and none of its own (GL 4.6 core 11.2.2 gives such a program a
+            // fixed-function pass-through; Vulkan has no such thing and
+            // VUID-VkGraphicsPipelineCreateInfo-pStages-00730 forbids the half-tessellated
+            // pipeline outright). Appended to `stages` at creation. A null module means the
+            // renderer could not build one, and CreatePipeline refuses the pipeline - the same
+            // refusal it applies when `stages` itself is half-tessellated.
+            //
+            // NOT hashed: it is a pure function of the program and of patchControlPoints, both
+            // of which ComputeHash already mixes in.
+            VkPipelineShaderStageCreateInfo passthroughTessControlStage{};
             const VkPipelineVertexInputStateCreateInfo* vertexInputState = nullptr;
             // Diagnostic only; may be null. Read solely from the pipeline-creation failure path.
             const Vector<ShaderStageSpirvDigest>* stageSpirvDigests = nullptr;

MobileGL/MG_Backend/DirectVulkan/Renderer/ProgramFactory.cpp

@@ -33,6 +33,32 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         using SpvcSession = MG_Util::ShaderTranspiler::SpvcSession;
         using SessionUsageBit = MG_Util::ShaderTranspiler::SessionUsageBit;
 
+        // Local size of a compute module, read from OpExecutionMode LocalSize; all-zero
+        // when absent. The compile chain pins SPIR-V 1.3, where a literal local size
+        // always reaches the module as this execution mode (LocalSizeId does not exist
+        // yet).
+        struct ComputeLocalSize {
+            Uint32 x = 0;
+            Uint32 y = 0;
+            Uint32 z = 0;
+            Uint64 Total() const { return static_cast<Uint64>(x) * y * z; }
+        };
+        ComputeLocalSize TryGetComputeLocalSize(const Vector<Uint>& spirv) {
+            constexpr SizeT kHeaderWords = 5;
+            constexpr Uint32 kOpExecutionMode = 16;
+            constexpr Uint32 kModeLocalSize = 17;
+            for (SizeT offset = kHeaderWords; offset < spirv.size();) {
+                const Uint32 wordCount = spirv[offset] >> 16u;
+                const Uint32 opcode = spirv[offset] & 0xffffu;
+                if (wordCount == 0 || offset + wordCount > spirv.size()) break;
+                if (opcode == kOpExecutionMode && wordCount >= 6 && spirv[offset + 2] == kModeLocalSize) {
+                    return {spirv[offset + 3], spirv[offset + 4], spirv[offset + 5]};
+                }
+                offset += wordCount;
+            }
+            return {};
+        }
+
         struct DescriptorKey {
             ProgramFactory::DescriptorBindingKind kind = ProgramFactory::DescriptorBindingKind::None;
             String name;
@@ -57,7 +83,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             Bool isMember = false;
         };
 
-        ShaderStage PickClipFixupStage(const Vector<SharedPtr<ShaderObject>>& shaders);
+        ShaderStage PickClipFixupStage(const Vector<ShaderStage>& stages);
 
         Bool IsVec4Float32(spvtools::opt::IRContext* context, Uint32 typeId, Uint32* outFloatTypeId) {
             auto* vecInst = context->get_def_use_mgr()->GetDef(typeId);
@@ -376,12 +402,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             spv_diagnostic diagnostic = nullptr;
             const spv_result_t result = spvValidateWithOptions(context, options, &binary, &diagnostic);
             if (result != SPV_SUCCESS) {
-                // MGLOG_I, not E: at the INFO compile level of the CI/test lanes that arm
-                // the validation switch, MGLOG_E is compiled out (Log.h orders
-                // DEBUG < WARN < ERROR < INFO) and the VUID would never reach a log. The
-                // latch is what a test harness asserts on.
+                // MGLOG_E, unlatched: reaching here already requires the validation switch to
+                // be armed, which bounds the volume, and each VUID names a different defect.
+                // (Parked at MGLOG_I until the Log.h level ordering was fixed, when E was
+                // compiled out of every INFO build.) The latch is what a test harness asserts on.
                 MG_Util::ShaderTranspiler::ShaderCompiler::NoteSpirvValidationFailure();
-                MGLOG_I(
+                MGLOG_E(
                     "ProgramFactory::ValidateTransformedSpirv: validation failed for stage=%d program=%u result=%d index=%zu msg=%s",
                     static_cast<Int>(shaderStage),
                     programExternalIndex,
@@ -588,15 +614,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         void ReflectStageInterface(ShaderStage targetStage,
                                    Bool reflectInputs,
-                                   const Vector<SharedPtr<ShaderObject>>& shaders,
+                                   const Vector<ShaderStage>& stages,
                                    const Vector<Vector<Uint>>& spirv,
                                    StageInterfaceSummary& outSummary,
                                    Uint programExternalIndex,
                                    const char* stageLabel) {
             outSummary.slotSignatures.fill(0);
 
-            for (SizeT moduleIndex = 0; moduleIndex < shaders.size() && moduleIndex < spirv.size(); ++moduleIndex) {
-                if (!shaders[moduleIndex] || shaders[moduleIndex]->GetShaderStage() != targetStage) {
+            for (SizeT moduleIndex = 0; moduleIndex < stages.size() && moduleIndex < spirv.size(); ++moduleIndex) {
+                if (stages[moduleIndex] != targetStage) {
                     continue;
                 }
 
@@ -664,11 +690,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             }
         }
 
-        void ValidateRasterizationStageInterface(const Vector<SharedPtr<ShaderObject>>& shaders,
+        void ValidateRasterizationStageInterface(const Vector<ShaderStage>& stages,
                                                  const Vector<Vector<Uint>>& spirv,
                                                  ProgramFactory::VkProgramObject& entry,
                                                  Uint programExternalIndex) {
-            const ShaderStage producerStage = PickClipFixupStage(shaders);
+            const ShaderStage producerStage = PickClipFixupStage(stages);
             entry.rasterizationProducerStage = producerStage;
             entry.producerOutputComponentCount = 0;
             entry.fragmentInputComponentCount = 0;
@@ -677,8 +703,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             }
 
             Bool hasFragmentStage = false;
-            for (const auto& shader : shaders) {
-                if (shader && shader->GetShaderStage() == ShaderStage::Fragment) {
+            for (const ShaderStage stage : stages) {
+                if (stage == ShaderStage::Fragment) {
                     hasFragmentStage = true;
                     break;
                 }
@@ -689,9 +715,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
             StageInterfaceSummary producerOutputs{};
             StageInterfaceSummary fragmentInputs{};
-            ReflectStageInterface(producerStage, false, shaders, spirv, producerOutputs, programExternalIndex,
+            ReflectStageInterface(producerStage, false, stages, spirv, producerOutputs, programExternalIndex,
                                   "producer");
-            ReflectStageInterface(ShaderStage::Fragment, true, shaders, spirv, fragmentInputs, programExternalIndex,
+            ReflectStageInterface(ShaderStage::Fragment, true, stages, spirv, fragmentInputs, programExternalIndex,
                                   "fragment");
             entry.producerOutputComponentCount = CountOccupiedStageInterfaceSlots(producerOutputs);
             entry.fragmentInputComponentCount = CountOccupiedStageInterfaceSlots(fragmentInputs);
@@ -1266,7 +1292,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     for (SizeT i = 1; i < group.offsets.size(); ++i) {
                         if (group.elementBytes == 0 ||
                             group.offsets[i] != group.offsets[i - 1] + group.elementBytes) {
-                            MGLOG_I("XfbCaptureDecoratePass: block member %u of type %%%u is captured with a "
+                            MGLOG_D("XfbCaptureDecoratePass: block member %u of type %%%u is captured with a "
                                     "non-contiguous element set; the capture layout will differ from GL's",
                                     key.second, key.first);
                             break;
@@ -1693,14 +1719,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             return success;
         }
 
-        ShaderStage PickClipFixupStage(const Vector<SharedPtr<ShaderObject>>& shaders) {
+        ShaderStage PickClipFixupStage(const Vector<ShaderStage>& stages) {
             Bool hasGeometry = false;
             Bool hasTessEval = false;
             Bool hasVertex = false;
 
-            for (const auto& shader : shaders) {
-                if (!shader) continue;
-                const auto stage = shader->GetShaderStage();
+            for (const ShaderStage stage : stages) {
                 hasGeometry |= (stage == ShaderStage::Geometry);
                 hasTessEval |= (stage == ShaderStage::TessEval);
                 hasVertex |= (stage == ShaderStage::Vertex);
@@ -1855,16 +1879,16 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     // unification and the set->0 normalisation this function exists to do. A
                     // program with an image array plus any second descriptor got aliased
                     // bindings out of that, and a DEBUG build trapped on the same program.
-                    // Which is also why the message below is MGLOG_I: MGLOG_E is compiled out
-                    // of an INFO build, so a refusal that only said MGLOG_E said nothing at all
-                    // in the builds that ship.
+                    // The refusal below is MGLOG_E and per-program-compile, so it reports every
+                    // program it declines. It spent time at MGLOG_I because the old level
+                    // ordering compiled E out of the builds that ship.
                     const Bool arraySupportedForKind =
                         kind == ProgramFactory::DescriptorBindingKind::UniformBufferDynamic ||
                         kind == ProgramFactory::DescriptorBindingKind::StorageBuffer ||
                         kind == ProgramFactory::DescriptorBindingKind::StorageImage ||
                         kind == ProgramFactory::DescriptorBindingKind::CombinedImageSampler;
                     if (binding->count != 1 && !arraySupportedForKind) {
-                        MGLOG_I("ProgramFactory: descriptor arrays are unsupported for this descriptor "
+                        MGLOG_E("ProgramFactory: descriptor arrays are unsupported for this descriptor "
                                 "kind (name='%s' count=%u type=%d)",
                                 binding->name ? binding->name : "<null>", binding->count,
                                 static_cast<Int>(binding->descriptor_type));
@@ -1997,6 +2021,29 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return ReflectedDeclaresInputBuiltin(reflectModule, SpvBuiltInBaseVertex);
     }
 
+    // gl_ViewportIndex on the last pre-rasterization stage. glslang emits it natively for Vulkan
+    // (BuiltIn ViewportIndex plus OpCapability MultiViewport), and nothing in the SpirvPasses
+    // chain touches it, so a plain reflection of the declared output builtins is the whole test.
+    Bool ProgramFactory::ReflectedWritesViewportIndexBuiltin(const SpvReflectShaderModule& reflectModule) {
+        return ReflectedDeclaresOutputBuiltin(reflectModule, SpvBuiltInViewportIndex);
+    }
+
+    Bool ProgramFactory::ReflectedDeclaresOutputBuiltin(const SpvReflectShaderModule& reflectModule,
+                                                       SpvBuiltIn builtin) {
+        for (Uint32 entryIndex = 0; entryIndex < reflectModule.entry_point_count; ++entryIndex) {
+            const SpvReflectEntryPoint& entryPoint = reflectModule.entry_points[entryIndex];
+            for (Uint32 variableIndex = 0; variableIndex < entryPoint.output_variable_count; ++variableIndex) {
+                const SpvReflectInterfaceVariable* variable = entryPoint.output_variables[variableIndex];
+                if (variable != nullptr &&
+                    (variable->decoration_flags & SPV_REFLECT_DECORATION_BUILT_IN) != 0 &&
+                    variable->built_in == builtin) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
     Bool ProgramFactory::ReflectedDeclaresInputBuiltin(const SpvReflectShaderModule& reflectModule,
                                                        SpvBuiltIn builtin) {
         for (Uint32 entryIndex = 0; entryIndex < reflectModule.entry_point_count; ++entryIndex) {
@@ -2045,7 +2092,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         case SpvImageFormatR11fG11fB10f: return VK_FORMAT_B10G11R11_UFLOAT_PACK32;
         case SpvImageFormatR16f: return VK_FORMAT_R16_SFLOAT;
         case SpvImageFormatRgba16: return VK_FORMAT_R16G16B16A16_UNORM;
-        case SpvImageFormatRgb10A2: return VK_FORMAT_A2R10G10B10_UNORM_PACK32;
+        // A2**B**10G10R10, matching MGToVk::ConvertTextureInternalFormatToVkFormat's RGB10A2.
+        // This value becomes the storage image VIEW's format while the image itself was created
+        // from the texture's internal format, so the two must name the same bit layout or the
+        // shader reads the texel through a different component order than the host wrote it.
+        // GL_RGB10_A2 with GL_UNSIGNED_INT_2_10_10_10_REV puts R in bits 0-9, G in 10-19, B in
+        // 20-29 and A in 30-31, which is Vulkan's A2B10G10R10; A2R10G10B10 transposes R and B.
+        // KHR-GL43.shader_image_load_store.basic-allFormats-store read back [2,1,0,3] for an
+        // rgb10_a2ui image stored as [0,1,2,3] while these two converters disagreed.
+        case SpvImageFormatRgb10A2: return VK_FORMAT_A2B10G10R10_UNORM_PACK32;
         case SpvImageFormatRg16: return VK_FORMAT_R16G16_UNORM;
         case SpvImageFormatRg8: return VK_FORMAT_R8G8_UNORM;
         case SpvImageFormatR16: return VK_FORMAT_R16_UNORM;
@@ -2068,7 +2123,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         case SpvImageFormatRgba16ui: return VK_FORMAT_R16G16B16A16_UINT;
         case SpvImageFormatRgba8ui: return VK_FORMAT_R8G8B8A8_UINT;
         case SpvImageFormatR32ui: return VK_FORMAT_R32_UINT;
-        case SpvImageFormatRgb10a2ui: return VK_FORMAT_A2R10G10B10_UINT_PACK32;
+        case SpvImageFormatRgb10a2ui: return VK_FORMAT_A2B10G10R10_UINT_PACK32; // see Rgb10A2 above
         case SpvImageFormatRg32ui: return VK_FORMAT_R32G32_UINT;
         case SpvImageFormatRg16ui: return VK_FORMAT_R16G16_UINT;
         case SpvImageFormatRg8ui: return VK_FORMAT_R8G8_UINT;
@@ -2259,15 +2314,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
     }
 
-    void ProgramFactory::ReflectVertexInputs(const Vector<SharedPtr<MG_State::GLState::ShaderObject>>& shaders,
+    void ProgramFactory::ReflectVertexInputs(const Vector<ShaderStage>& stages,
                                              const Vector<Vector<Uint>>& spirv,
                                              VkProgramObject& entry) const {
         entry.activeVertexInputLocationMask = 0;
         entry.vertexInputTypes.fill(0);
         entry.readsBaseVertexBuiltin = false;
 
-        for (SizeT moduleIndex = 0; moduleIndex < shaders.size() && moduleIndex < spirv.size(); ++moduleIndex) {
-            if (!shaders[moduleIndex] || shaders[moduleIndex]->GetShaderStage() != ShaderStage::Vertex) {
+        for (SizeT moduleIndex = 0; moduleIndex < stages.size() && moduleIndex < spirv.size(); ++moduleIndex) {
+            if (stages[moduleIndex] != ShaderStage::Vertex) {
                 continue;
             }
 
@@ -2339,15 +2394,54 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
     }
 
-    void ProgramFactory::ReflectFragmentOutputs(const Vector<SharedPtr<MG_State::GLState::ShaderObject>>& shaders,
+    // Which pre-rasterization stage assigns gl_ViewportIndex is not fixed: GL 4.1 allows only the
+    // geometry stage, ARB_shader_viewport_layer_array/GL 4.6 also the vertex and tessellation
+    // evaluation stages. Rather than guess which one is last, every non-fragment, non-compute
+    // module is asked - one writer anywhere means this program's draws need a multi-viewport
+    // pipeline, and a false positive costs only a wider viewportCount.
+    void ProgramFactory::ReflectViewportIndexUsage(const Vector<ShaderStage>& stages,
+                                                   const Vector<Vector<Uint>>& spirv,
+                                                   VkProgramObject& entry) const {
+        entry.writesViewportIndexBuiltin = false;
+
+        for (SizeT moduleIndex = 0; moduleIndex < stages.size() && moduleIndex < spirv.size(); ++moduleIndex) {
+            const ShaderStage stage = stages[moduleIndex];
+            if (stage == ShaderStage::Fragment || stage == ShaderStage::Compute) continue;
+
+            const auto& module = spirv[moduleIndex];
+            if (module.empty()) continue;
+
+            SpvReflectShaderModule reflectModule{};
+            const SpvReflectResult createResult =
+                spvReflectCreateShaderModule(module.size() * sizeof(Uint), module.data(), &reflectModule);
+            if (createResult != SPV_REFLECT_RESULT_SUCCESS) {
+                // Fail toward the wide pipeline. Missing a real gl_ViewportIndex writer would
+                // silently collapse every viewport onto 0 (the exact bug this reflection exists
+                // to fix); over-declaring costs one extra viewport slot on a program that never
+                // uses it.
+                MGLOG_E_ONCE("ProgramFactory::ReflectViewportIndexUsage: reflection failed (result=%d); assuming the "
+                             "program writes gl_ViewportIndex",
+                             static_cast<Int>(createResult));
+                entry.writesViewportIndexBuiltin = true;
+                continue;
+            }
+
+            if (ReflectedWritesViewportIndexBuiltin(reflectModule)) {
+                entry.writesViewportIndexBuiltin = true;
+            }
+            spvReflectDestroyShaderModule(&reflectModule);
+        }
+    }
+
+    void ProgramFactory::ReflectFragmentOutputs(const Vector<ShaderStage>& stages,
                                                 const Vector<Vector<Uint>>& spirv,
                                                 VkProgramObject& entry) const {
         entry.activeFragmentOutputLocationMask = 0;
         entry.fragmentOutputTypes.fill(0);
         entry.fragmentReplacesDepth = false;
 
-        for (SizeT moduleIndex = 0; moduleIndex < shaders.size() && moduleIndex < spirv.size(); ++moduleIndex) {
-            if (!shaders[moduleIndex] || shaders[moduleIndex]->GetShaderStage() != ShaderStage::Fragment) {
+        for (SizeT moduleIndex = 0; moduleIndex < stages.size() && moduleIndex < spirv.size(); ++moduleIndex) {
+            if (stages[moduleIndex] != ShaderStage::Fragment) {
                 continue;
             }
 
@@ -2468,7 +2562,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // inert; a device whose binding cap is smaller than a shader's array is not a
             // configuration MobileGL can serve at all. Needs a >maxBindings-element array to
             // reach (256 on desktop, ~16 on mobile).
-            MGLOG_I("ProgramFactory::ReflectLayout: %s array '%s' at binding %u has %u elements, past the %u "
+            MGLOG_D("ProgramFactory::ReflectLayout: %s array '%s' at binding %u has %u elements, past the %u "
                     "this device can describe - declining the program",
                     kindLabel, uniformName.c_str(), binding, count, maxBindings);
             outDeclined = true;
@@ -2476,7 +2570,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
         if (baseLocation < 0 ||
             !program.UniformLocationsAliasSameUniform(baseLocation, baseLocation + static_cast<Int>(count - 1u))) {
-            MGLOG_I("ProgramFactory::ReflectLayout: %s array '%s' at binding %u spans %u descriptors but the "
+            MGLOG_D("ProgramFactory::ReflectLayout: %s array '%s' at binding %u spans %u descriptors but the "
                     "reflection reserved fewer uniform locations for it (base=%d) - a multi-dimensional array "
                     "is the usual cause, and MobileGL declines it rather than resolve elements onto a "
                     "neighbouring uniform",
@@ -2713,7 +2807,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     // a Uint16 on the way, where 65536 would silently become 0.
                     const Uint32 storageArrayCount = std::max<Uint32>(1u, sampler->count);
                     if (storageArrayCount > m_maxBindings) {
-                        MGLOG_I("ProgramFactory::ReflectLayout: storage block array '%s' at binding %u has %u "
+                        MGLOG_D("ProgramFactory::ReflectLayout: storage block array '%s' at binding %u has %u "
                                 "elements, past the %u this device can describe - declining the program",
                                 uniformName.c_str(), binding, storageArrayCount, m_maxBindings);
                         entry.declinedDescriptors = true;
@@ -2736,7 +2830,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     // so at a level that survives a release build, because dropping the binding
                     // leaves the shader reading a descriptor the layout never declared.
                     if (sampler->count > 1) {
-                        MGLOG_I("ProgramFactory::ReflectLayout: declining '%s' at binding %u - a %u-element "
+                        MGLOG_E("ProgramFactory::ReflectLayout: declining '%s' at binding %u - a %u-element "
                                 "descriptor array with no frontend uniform location (a multi-dimensional array "
                                 "of samplers or images is the known cause)",
                                 uniformName.c_str(), binding, sampler->count);
@@ -2910,8 +3004,73 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             bindings.push_back(layoutBinding);
         }
 
+        // UPDATE_AFTER_BIND is strictly an optional per-layout acceleration. The GL
+        // descriptor model still resolves every sampler uniform element independently
+        // (including its texture-unit sampler-object override); selecting this path
+        // changes neither that resolution nor the set versioning in UniformManager.
+        // A conservative count keeps a layout on ordinary descriptors whenever any
+        // relevant update-after-bind limit is not large enough, rather than asking a
+        // driver to reject it during vkCreateDescriptorSetLayout.
+        Uint32 updateAfterBindSamplers = 0;
+        Uint32 updateAfterBindUniformBuffers = 0;
+        Uint32 updateAfterBindStorageBuffers = 0;
+        Uint32 updateAfterBindSampledImages = 0;
+        Uint32 updateAfterBindStorageImages = 0;
+        for (Uint32 binding = 0; binding < m_maxBindings; ++binding) {
+            const Uint32 count = entry.bindingDescriptorCounts[binding];
+            switch (entry.bindingKinds[binding]) {
+                case DescriptorBindingKind::UniformBufferDynamic:
+                    updateAfterBindUniformBuffers += count;
+                    break;
+                case DescriptorBindingKind::CombinedImageSampler:
+                    updateAfterBindSamplers += count;
+                    updateAfterBindSampledImages += count;
+                    break;
+                case DescriptorBindingKind::UniformTexelBuffer:
+                    updateAfterBindSampledImages += count;
+                    break;
+                case DescriptorBindingKind::StorageBuffer:
+                case DescriptorBindingKind::StorageTexelBuffer:
+                    updateAfterBindStorageBuffers += count;
+                    break;
+                case DescriptorBindingKind::StorageImage:
+                    updateAfterBindStorageImages += count;
+                    break;
+                case DescriptorBindingKind::None:
+                    break;
+            }
+        }
+        const Uint32 updateAfterBindResources = updateAfterBindUniformBuffers + updateAfterBindStorageBuffers +
+                                                updateAfterBindSampledImages + updateAfterBindStorageImages;
+        const auto& uab = m_updateAfterBindLimits;
+        entry.usesUpdateAfterBind =
+            uab.enabled && updateAfterBindSamplers <= uab.maxPerStageSamplers &&
+            updateAfterBindUniformBuffers <= uab.maxPerStageUniformBuffers &&
+            updateAfterBindStorageBuffers <= uab.maxPerStageStorageBuffers &&
+            updateAfterBindSampledImages <= uab.maxPerStageSampledImages &&
+            updateAfterBindStorageImages <= uab.maxPerStageStorageImages &&
+            updateAfterBindResources <= uab.maxPerStageResources &&
+            updateAfterBindSamplers <= uab.maxSetSamplers &&
+            updateAfterBindUniformBuffers <= uab.maxSetUniformBuffers &&
+            updateAfterBindUniformBuffers <= uab.maxSetUniformBuffersDynamic &&
+            updateAfterBindStorageBuffers <= uab.maxSetStorageBuffers &&
+            updateAfterBindStorageBuffers <= uab.maxSetStorageBuffersDynamic &&
+            updateAfterBindSampledImages <= uab.maxSetSampledImages &&
+            updateAfterBindStorageImages <= uab.maxSetStorageImages;
+
+        Vector<VkDescriptorBindingFlags> bindingFlags;
+        VkDescriptorSetLayoutBindingFlagsCreateInfo bindingFlagsInfo{};
+        if (entry.usesUpdateAfterBind) {
+            bindingFlags.assign(bindings.size(), VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT);
+            bindingFlagsInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO;
+            bindingFlagsInfo.bindingCount = static_cast<Uint32>(bindingFlags.size());
+            bindingFlagsInfo.pBindingFlags = bindingFlags.data();
+        }
+
         VkDescriptorSetLayoutCreateInfo setLayoutInfo{};
         setLayoutInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
+        setLayoutInfo.flags = entry.usesUpdateAfterBind ? VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT : 0;
+        setLayoutInfo.pNext = entry.usesUpdateAfterBind ? &bindingFlagsInfo : nullptr;
         setLayoutInfo.bindingCount = static_cast<Uint32>(bindings.size());
         setLayoutInfo.pBindings = bindings.data();
         VK_VERIFY(vkCreateDescriptorSetLayout(m_device, &setLayoutInfo, nullptr, &entry.descriptorSetLayout),
@@ -2988,18 +3147,30 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         auto& entry = m_cache[hash];
         entry.hash = hash;
         entry.lastUsedFrame = m_frameCounter;
-        auto& shaders = program.GetAttachedShaders();
+        // The EXECUTABLE's stage list, not GetAttachedShaders(): `spirv` is a link artifact with
+        // one module per linked stage, while the attach list is live and grows on
+        // glAttachShader, which GL 4.6 core 7.3 says does not reach the executable until the
+        // next link. Sizing this loop by the attach list therefore ran it past the end of both
+        // `spirv` and `moduleSpirvs` for any program attached to after it linked.
+        const Vector<ShaderStage> stages = program.GetLinkedShaderStages();
         auto& spirv = program.GetGeneratedSpirv();
         Vector<Vector<Uint>> moduleSpirvs(spirv.size());
+        const Bool enableSpirvValidation = program.GetSpirvValidationEnabled();
+        if (enableSpirvValidation) {
+            MG_Util::ShaderTranspiler::ShaderCompiler::PrepareSpirvValidation();
+        }
 
-        const ShaderStage fixupStage = PickClipFixupStage(shaders);
+        const ShaderStage fixupStage = PickClipFixupStage(stages);
 
-        for (SizeT i = 0; i < shaders.size(); ++i) {
+        // Both lists come from the same Link(), so they agree by construction; the min() is what
+        // makes that an assumption this loop does not have to bet the process on.
+        const SizeT moduleCount = std::min(stages.size(), spirv.size());
+        for (SizeT i = 0; i < moduleCount; ++i) {
             auto& spv = spirv[i];
             if (spv.empty()) continue;
 
             // Apply position fixup if needed
-            if (fixupStage != ShaderStage::Unknown && shaders[i] && shaders[i]->GetShaderStage() == fixupStage) {
+            if (fixupStage != ShaderStage::Unknown && stages[i] == fixupStage) {
                 const Vector<Uint>* fixupInput = &spv;
                 Vector<Uint> xfbSpirv;
                 if ((flags & ProgramFactory::CompileOptionBit::XfbCapture) &&
@@ -3015,28 +3186,95 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 moduleSpirvs[i] = spv;
             }
 
-            if ((flags & ProgramFactory::CompileOptionBit::ExplicitLod0Sampling) && shaders[i] &&
-                shaders[i]->GetShaderStage() == ShaderStage::Fragment) {
+            if ((flags & ProgramFactory::CompileOptionBit::ExplicitLod0Sampling) && stages[i] == ShaderStage::Fragment) {
                 Vector<Uint> explicitLodSpirv;
                 if (TransformSpirvForExplicitLod0Sampling(moduleSpirvs[i], explicitLodSpirv)) {
                     moduleSpirvs[i] = Move(explicitLodSpirv);
                 }
             }
 
-            if ((flags & ProgramFactory::CompileOptionBit::FragCoordYFlip) && shaders[i] &&
-                shaders[i]->GetShaderStage() == ShaderStage::Fragment) {
+            if ((flags & ProgramFactory::CompileOptionBit::FragCoordYFlip) && stages[i] == ShaderStage::Fragment) {
                 Vector<Uint> fragCoordSpirv;
                 if (TransformSpirvForFragCoordYFlip(moduleSpirvs[i], fragCoordSpirv, m_defaultFramebufferHeight)) {
                     moduleSpirvs[i] = Move(fragCoordSpirv);
                 }
             }
 
+            // GL_KHR_shader_subgroup handling (SubgroupSupportPolicy.h). Native subgroup
+            // operations execute natively; module repairs keep the GL contract intact
+            // around them. The opt-in emulation path replaces them only on devices with no
+            // subgroup support at all (MOBILEGL_MAGMA_EMULATE_SUBGROUP).
+            if (stages[i] == ShaderStage::Compute) {
+                // Program 203 broadcasts the first reduction through
+                // prefixSumCache[0], then lets the second reduction overwrite that
+                // scratch without first rendezvousing all readers. Patch that exact
+                // fingerprint before either native or emulated subgroup lowering.
+                if (m_subgroupPolicy.fixIterationRPBarrier) {
+                    Vector<Uint> patchedSpirv;
+                    if (MG_Util::ShaderTranspiler::ShaderCompiler::FixIterationRPBarrierForVulkan(
+                            moduleSpirvs[i], patchedSpirv, enableSpirvValidation)) {
+                        moduleSpirvs[i] = std::move(patchedSpirv);
+                    } else {
+                        MGLOG_E("ProgramFactory: iterationRP barrier patch failed for program %u; "
+                                "Program 203 keeps its shared-scratch race",
+                                program.GetExternalIndex());
+                    }
+                }
+                if (m_subgroupPolicy.emulateSubgroups) {
+                    Vector<Uint> emulatedSpirv;
+                    if (MG_Util::ShaderTranspiler::ShaderCompiler::EmulateSubgroupsForVulkan(
+                            moduleSpirvs[i], emulatedSpirv,
+                            m_subgroupPolicy.maxComputeSharedMemoryBytes, enableSpirvValidation)) {
+                        moduleSpirvs[i] = std::move(emulatedSpirv);
+                    } else {
+                        MGLOG_E("ProgramFactory: subgroup emulation failed for program %u; the "
+                                "module keeps subgroup operations the device cannot execute",
+                                program.GetExternalIndex());
+                    }
+                } else {
+                    // iterationRP under-declares its cross-subgroup scratch
+                    // (prefixSumCache[32] for 512 invocations); on a sub-16-lane device
+                    // grow that one fingerprinted array to what the topology needs.
+                    if (m_subgroupPolicy.fixIterationRPSubgroupScratch) {
+                        Vector<Uint> patchedSpirv;
+                        if (MG_Util::ShaderTranspiler::ShaderCompiler::FixIterationRPSubgroupScratchForVulkan(
+                                moduleSpirvs[i], patchedSpirv, m_subgroupPolicy.nativeSubgroupSize,
+                                m_subgroupPolicy.maxComputeSharedMemoryBytes,
+                                enableSpirvValidation)) {
+                            moduleSpirvs[i] = std::move(patchedSpirv);
+                        } else {
+                            MGLOG_E("ProgramFactory: iterationRP subgroup scratch patch failed for "
+                                    "program %u; the pack's declared array sizes stay in effect",
+                                    program.GetExternalIndex());
+                        }
+                    }
+                    // gl_NumSubgroups must agree with the gl_SubgroupID range GL promises;
+                    // derive it from the workgroup dimensions and gl_SubgroupSize instead of
+                    // trusting a driver builtin that can disagree with the topology the same
+                    // dispatch emits (Adreno reports 1 while emitting IDs 0..7 for a
+                    // 512-invocation, 64-wide workgroup). The ceil() partition this derives
+                    // is pinned by REQUIRE_FULL_SUBGROUPS at pipeline creation whenever the
+                    // workgroup shape makes that flag legal (see the stage setup below).
+                    if (m_subgroupPolicy.deriveNumSubgroups) {
+                        Vector<Uint> derivedNumSubgroupsSpirv;
+                        if (MG_Util::ShaderTranspiler::ShaderCompiler::DeriveNumSubgroupsForVulkan(
+                                moduleSpirvs[i], derivedNumSubgroupsSpirv, enableSpirvValidation)) {
+                            moduleSpirvs[i] = std::move(derivedNumSubgroupsSpirv);
+                        } else {
+                            MGLOG_E("ProgramFactory: failed to derive gl_NumSubgroups for program %u; "
+                                    "compute shaders may observe a driver-inconsistent subgroup count",
+                                    program.GetExternalIndex());
+                        }
+                    }
+                }
+            }
+
             // Vulkan's SPIR-V environment has no rectangle image dimension, so a
             // GL_TEXTURE_RECTANGLE lookup has to become the 2D one the texture is really
             // stored as - which addresses [0,1] where the application addressed texels.
             {
                 Vector<Uint> rectLoweredSpirv;
-                if (MG_Util::ShaderTranspiler::ShaderCompiler::LowerRectImages(moduleSpirvs[i], rectLoweredSpirv) &&
+                if (MG_Util::ShaderTranspiler::ShaderCompiler::LowerRectImages(moduleSpirvs[i], rectLoweredSpirv, enableSpirvValidation) &&
                     !rectLoweredSpirv.empty()) {
                     moduleSpirvs[i] = Move(rectLoweredSpirv);
                 }
@@ -3049,7 +3287,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             {
                 Vector<Uint> invariantSpirv;
                 if (MG_Util::ShaderTranspiler::ShaderCompiler::DecoratePositionInvariantForVulkan(
-                        moduleSpirvs[i], invariantSpirv)) {
+                        moduleSpirvs[i], invariantSpirv, enableSpirvValidation)) {
                     moduleSpirvs[i] = std::move(invariantSpirv);
                 } else {
                     // The pass round-trips through SPIRV-Tools IR, so an unparseable module
@@ -3069,11 +3307,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // The unsupported-device counterpart of this rebase (warning when a shader reads
             // the builtin but shaderDrawParameters is missing) rides along with
             // ReflectVertexInputs, which already reflects this stage.
-            if (shaders[i] && shaders[i]->GetShaderStage() == ShaderStage::Vertex &&
-                m_shaderDrawParametersEnabled) {
+            if (stages[i] == ShaderStage::Vertex && m_shaderDrawParametersEnabled) {
                 Vector<Uint> rebasedSpirv;
                 if (MG_Util::ShaderTranspiler::ShaderCompiler::RebaseInstanceIndexForVulkan(moduleSpirvs[i],
-                                                                                            rebasedSpirv)) {
+                                                                                            rebasedSpirv, enableSpirvValidation)) {
                     moduleSpirvs[i] = std::move(rebasedSpirv);
                 } else {
                     MGLOG_E("ProgramFactory: failed to rebase gl_InstanceID for program %u; "
@@ -3087,11 +3324,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // through CompileOptionBit::ZeroBaseVertex, so the indexed variant of the same
             // program keeps the native builtin and stays correct for glDrawElementsBaseVertex
             // and for the baseVertex word of an indexed indirect command.
-            if (shaders[i] && shaders[i]->GetShaderStage() == ShaderStage::Vertex &&
-                (flags & CompileOptionBit::ZeroBaseVertex)) {
+            if (stages[i] == ShaderStage::Vertex && (flags & CompileOptionBit::ZeroBaseVertex)) {
                 Vector<Uint> zeroedSpirv;
                 if (MG_Util::ShaderTranspiler::ShaderCompiler::ZeroBaseVertexForVulkan(moduleSpirvs[i],
-                                                                                       zeroedSpirv)) {
+                                                                                       zeroedSpirv, enableSpirvValidation)) {
                     moduleSpirvs[i] = std::move(zeroedSpirv);
                 } else {
                     // Failing open keeps the native builtin, which is the pre-fix behavior:
@@ -3111,10 +3347,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // committed to R32G32{,B32A32}_UINT for the attribute, so a module still declaring
             // `in double` would reconcile to Unknown and build a pipeline with a UINT format under a
             // double input - garbage with no diagnostic anywhere.
-            if (shaders[i] && shaders[i]->GetShaderStage() == ShaderStage::Vertex) {
+            if (stages[i] == ShaderStage::Vertex) {
                 Vector<Uint> packedSpirv;
                 const Bool packOk = MG_Util::ShaderTranspiler::ShaderCompiler::PackDoubleVertexInputsForVulkan(
-                    moduleSpirvs[i], packedSpirv);
+                    moduleSpirvs[i], packedSpirv, enableSpirvValidation);
                 MOBILEGL_ASSERT(packOk,
                                 "ProgramFactory: 64-bit vertex input packing failed for program %u; the "
                                 "vertex-input format and the shader input type now disagree",
@@ -3138,7 +3374,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             if (m_unformattedFloatStorageImagesEnabled) {
                 Vector<Uint> unformattedSpirv;
                 if (MG_Util::ShaderTranspiler::ShaderCompiler::UseUnformattedFloatStorageImagesForVulkan(
-                        moduleSpirvs[i], unformattedSpirv)) {
+                        moduleSpirvs[i], unformattedSpirv, enableSpirvValidation)) {
                     moduleSpirvs[i] = std::move(unformattedSpirv);
                 } else {
                     MGLOG_E("ProgramFactory: failed to make float storage images unformatted for program %u",
@@ -3150,17 +3386,17 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const Bool remapOk = RemapDescriptorBindingsForVulkan(moduleSpirvs, m_maxBindings, moduleSpirvs);
         MOBILEGL_ASSERT(remapOk, "ProgramFactory::GetOrCreateProgram: descriptor binding remap failed");
 
-        for (SizeT i = 0; i < shaders.size(); ++i) {
+        for (SizeT i = 0; i < moduleCount; ++i) {
             auto& moduleSpv = moduleSpirvs[i];
             if (moduleSpv.empty()) continue;
 
 #if MOBILEGL_LOG_ACTIVE_LEVEL <= MOBILEGL_LOG_LEVEL_DEBUG
-            ValidateTransformedSpirv(moduleSpv, shaders[i]->GetShaderStage(), program.GetExternalIndex());
+            ValidateTransformedSpirv(moduleSpv, stages[i], program.GetExternalIndex());
 #else
             // Final module the driver receives; also checked in the INFO-level CI/test
             // lanes, where the DEBUG gate above is compiled out.
-            if (MG_Util::ShaderTranspiler::ShaderCompiler::SpirvValidationEnabled()) {
-                ValidateTransformedSpirv(moduleSpv, shaders[i]->GetShaderStage(), program.GetExternalIndex());
+            if (enableSpirvValidation) {
+                ValidateTransformedSpirv(moduleSpv, stages[i], program.GetExternalIndex());
             }
 #endif
 
@@ -3172,10 +3408,31 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             VK_VERIFY(vkCreateShaderModule(m_device, &smci, nullptr, &module), "vkCreateShaderModule");
 
             VkPipelineShaderStageCreateInfo stage{VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO};
-            ShaderStage shaderStage = shaders[i]->GetShaderStage();
+            ShaderStage shaderStage = stages[i];
             stage.stage = ToVkStage(shaderStage);
             stage.module = module;
             stage.pName = "main";
+            // Pin the full-subgroup launch the derived gl_NumSubgroups assumes. Legal
+            // exactly when the computeFullSubgroups feature is enabled and local_size_x is
+            // a multiple of the subgroup size (VUID-VkPipelineShaderStageCreateInfo-
+            // flags-02759/-02785), and only worth requesting while the resulting subgroup
+            // count fits the device's maxComputeWorkgroupSubgroups (lavapipe caps it at
+            // 32, below a 512-invocation dispatch's 64). With the bit set, "Full
+            // Subgroups" guarantees every subgroup launches with all invocations active,
+            // making the subgroup count exactly invocations / size. Shapes the flag
+            // cannot cover (e.g. 32x16 on a 64-wide device) fall back to the driver's
+            // own - spec-encouraged - tight partitioning, which the DriverPost witness
+            // verifies per device.
+            if (shaderStage == ShaderStage::Compute && m_subgroupPolicy.requireFullSubgroups &&
+                !m_subgroupPolicy.emulateSubgroups && m_subgroupPolicy.nativeSubgroupSize != 0) {
+                const ComputeLocalSize localSize = TryGetComputeLocalSize(moduleSpv);
+                const Uint64 fullSubgroupCount =
+                    localSize.Total() / m_subgroupPolicy.nativeSubgroupSize;
+                if (localSize.x != 0 && localSize.x % m_subgroupPolicy.nativeSubgroupSize == 0 &&
+                    fullSubgroupCount <= m_subgroupPolicy.maxComputeWorkgroupSubgroups) {
+                    stage.flags |= VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT;
+                }
+            }
 
             entry.modules.push_back(module);
             entry.stages.push_back(stage);
@@ -3186,10 +3443,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         // Reflect and create layout as part of the program object
 #if MOBILEGL_LOG_ACTIVE_LEVEL <= MOBILEGL_LOG_LEVEL_DEBUG
-        ValidateRasterizationStageInterface(shaders, moduleSpirvs, entry, program.GetExternalIndex());
+        ValidateRasterizationStageInterface(stages, moduleSpirvs, entry, program.GetExternalIndex());
 #endif
-        ReflectVertexInputs(shaders, moduleSpirvs, entry);
-        ReflectFragmentOutputs(shaders, moduleSpirvs, entry);
+        ReflectVertexInputs(stages, moduleSpirvs, entry);
+        ReflectViewportIndexUsage(stages, moduleSpirvs, entry);
+        ReflectFragmentOutputs(stages, moduleSpirvs, entry);
+        ReflectPassthroughTessControlNeed(stages, moduleSpirvs, entry);
         ReflectLayout(program, moduleSpirvs, entry);
         // A failed remap means the modules kept glslang's per-stage auto-mapped binding numbers -
         // no cross-stage unification, no set->0 normalisation - so the bindings this layout
@@ -3200,7 +3459,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // "the layout and the shader disagree", so route it through that. Set AFTER ReflectLayout,
         // which clears the flag.
         if (!remapOk) {
-            MGLOG_I("ProgramFactory::GetOrCreateProgram: declining program %u - its descriptor bindings could not "
+            MGLOG_E("ProgramFactory::GetOrCreateProgram: declining program %u - its descriptor bindings could not "
                     "be remapped, so the layout does not describe what the shader reads",
                     program.GetExternalIndex());
             entry.declinedDescriptors = true;
@@ -3234,17 +3493,248 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 const VkDescriptorSetLayout descriptorSetLayout = it->second.descriptorSetLayout;
                 MGLOG_D("ProgramFactory::OnFrameBoundary: evicting idle program entry hash=0x%llx",
                         static_cast<unsigned long long>(hash));
-                // erase runs ~VkProgramObject (modules/layouts destroyed); notify after
-                // so an observer never observes a half-destroyed entry through a lookup.
-                // Observers only need the handle values to purge their keyed caches.
-                ++m_cacheStructureEpoch; // erase moves/kills entries: memoised pointers die
-                it = m_cache.erase(it);
+                // The observer destroys dependent pipelines and frees descriptor sets while
+                // this entry still owns its layout. Vulkan requires every descriptor set to be
+                // freed before its VkDescriptorSetLayout is destroyed.
                 if (m_evictionObserver != nullptr) {
                     m_evictionObserver->OnProgramEvicted(hash, descriptorSetLayout);
                 }
+                ++m_cacheStructureEpoch; // erase moves/kills entries: memoised pointers die
+                it = m_cache.erase(it);
             } else {
                 ++it;
             }
         }
     }
+
+    ProgramFactory::~ProgramFactory() {
+        for (auto& entry : m_passthroughTessControlStages) {
+            if (entry.second.module != VK_NULL_HANDLE) {
+                vkDestroyShaderModule(m_device, entry.second.module, nullptr);
+            }
+        }
+    }
+
+    String ProgramFactory::BuildPassthroughTessControlSource(Uint32 patchVertices) {
+        // The stage GL 4.6 core 11.2.2 describes when a program has an evaluation shader and no
+        // control shader: "the input patch is passed through unmodified", the output patch has
+        // as many vertices as the input one (PATCH_VERTICES), and the levels come from the
+        // PATCH_DEFAULT_OUTER_LEVEL / PATCH_DEFAULT_INNER_LEVEL state.
+        //
+        // Those two levels default to 1.0 and are baked here as literals because
+        // glPatchParameterfv - their only setter - is not implemented in this frontend (it is a
+        // stub in MG_Impl/GLImpl/Exporting/Definitions.cpp). Implementing that entry point means
+        // making the levels a parameter of this source AND of the cache key in
+        // GetOrCreatePassthroughTessControlStage; the two must move together, so they are named
+        // together here.
+        //
+        // gl_out carries gl_Position and nothing else on purpose. The evaluation stage that
+        // reads it was linked against the VERTEX stage directly, so its input gl_PerVertex holds
+        // exactly the built-ins that stage used, and its user-defined inputs (if any) come
+        // straight off the vertex stage's outputs - which a control stage sitting in between
+        // would leave unwritten. ReflectPassthroughTessControlNeed refuses those programs rather
+        // than let this write a partial interface.
+        //
+        // All four outer levels and both inner levels are written unconditionally: writing a
+        // level the evaluation stage's domain does not use is legal and ignored, and it saves
+        // this from having to know the domain.
+        String source = "#version 450 core\n";
+        source += "layout(vertices = " + std::to_string(patchVertices) + ") out;\n";
+        // gl_in and gl_out are redeclared to the exact gl_PerVertex the FRONTEND's linked programs
+        // carry - gl_Position, gl_PointSize, gl_ClipDistance[1], in that order - because Vulkan
+        // matches built-in interface blocks by their whole shape, and the two obvious spellings
+        // are both wrong:
+        //   * narrowing the block to gl_Position alone makes the evaluation stage read a patch of
+        //     zeroes (degenerate triangles, nothing rasterized), and
+        //   * taking glslang's DEFAULT block for a standalone control stage yields FOUR members -
+        //     it appends gl_CullDistance - where a linked vertex+evaluation program has three.
+        // PassthroughTessControlTest.MatchesTheFrontendPerVertexBlock is the latch: it links a
+        // vertex+evaluation program through this same compiler and fails if the two shapes ever
+        // stop agreeing, rather than letting the mismatch show up as a black frame.
+        //
+        // Only gl_Position is written. gl_PointSize is declared but left alone deliberately:
+        // writing it from a tessellation stage requires the shaderTessellationAndGeometryPointSize
+        // feature, which this renderer does not enable, so a program whose evaluation stage reads
+        // gl_in[].gl_PointSize gets an undefined point size instead of the vertex stage's - a gap
+        // this trades for not making every tessellated pipeline depend on an optional feature.
+        source += "in gl_PerVertex {\n"
+                  "    vec4 gl_Position;\n"
+                  "    float gl_PointSize;\n"
+                  "    float gl_ClipDistance[1];\n"
+                  "} gl_in[gl_MaxPatchVertices];\n";
+        source += "out gl_PerVertex {\n"
+                  "    vec4 gl_Position;\n"
+                  "    float gl_PointSize;\n"
+                  "    float gl_ClipDistance[1];\n"
+                  "} gl_out[];\n";
+        source += "void main() {\n";
+        source += "    gl_out[gl_InvocationID].gl_Position = gl_in[gl_InvocationID].gl_Position;\n";
+        source += "    gl_TessLevelOuter[0] = 1.0;\n";
+        source += "    gl_TessLevelOuter[1] = 1.0;\n";
+        source += "    gl_TessLevelOuter[2] = 1.0;\n";
+        source += "    gl_TessLevelOuter[3] = 1.0;\n";
+        source += "    gl_TessLevelInner[0] = 1.0;\n";
+        source += "    gl_TessLevelInner[1] = 1.0;\n";
+        source += "}\n";
+        return source;
+    }
+
+    VkPipelineShaderStageCreateInfo ProgramFactory::GetOrCreatePassthroughTessControlStage(Uint32 patchVertices) {
+        // A cached VK_NULL_HANDLE is a remembered failure, not a miss: returning it keeps a
+        // generator that cannot compile from re-running glslang on every draw.
+        const auto cached = m_passthroughTessControlStages.find(patchVertices);
+        if (cached != m_passthroughTessControlStages.end()) {
+            return cached->second;
+        }
+
+        VkPipelineShaderStageCreateInfo stage{VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO};
+        stage.stage = VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT;
+        stage.module = VK_NULL_HANDLE;
+        stage.pName = "main";
+
+        using namespace MG_Util::ShaderTranspiler;
+        const String source = BuildPassthroughTessControlSource(patchVertices);
+        // Same compile configuration as every other stage of every other program: this runs on
+        // the GL thread (the draw path), so the live compile env is the right one, and flags=0
+        // is the Vulkan-targeting form (CompileForOpenGL is what the GLES backend adds).
+        const SharedPtr<const CompileEnv>& env = GetCurrentCompileEnv();
+        ShaderAttrib shaderAttrib{.shaderType = GL_TESS_CONTROL_SHADER,
+                                  .sourceStr = source,
+                                  .flags = 0,
+                                  .env = env.get()};
+        auto compiled = ShaderCompiler::CompileShader(shaderAttrib);
+        if (!compiled) {
+            MGLOG_E("ProgramFactory: could not compile the pass-through tessellation control stage for "
+                    "patchVertices=%u; a program with an evaluation stage and no control stage cannot draw. %s",
+                    patchVertices, compiled.error().log.c_str());
+            m_passthroughTessControlStages.emplace(patchVertices, stage);
+            return stage;
+        }
+
+        ProgramAttrib programAttrib{};
+        programAttrib.shaders.push_back(compiled.value());
+        auto linked = ShaderCompiler::LinkProgram(programAttrib);
+        if (!linked) {
+            MGLOG_E("ProgramFactory: could not link the pass-through tessellation control stage for "
+                    "patchVertices=%u. %s", patchVertices, linked.error().log.c_str());
+            m_passthroughTessControlStages.emplace(patchVertices, stage);
+            return stage;
+        }
+
+        ProgramBinaryAttrib binaryAttrib{.shaderTypes = {GL_TESS_CONTROL_SHADER}, .program = *linked.value()};
+        auto binary = ShaderCompiler::GetSpirvBinaryFromProgram(binaryAttrib);
+        if (!binary || binary.value().empty() || binary.value().front().empty()) {
+            MGLOG_E("ProgramFactory: could not generate SPIR-V for the pass-through tessellation control stage "
+                    "for patchVertices=%u", patchVertices);
+            m_passthroughTessControlStages.emplace(patchVertices, stage);
+            return stage;
+        }
+
+        const Vector<Uint>& spirv = binary.value().front();
+#if MOBILEGL_LOG_ACTIVE_LEVEL <= MOBILEGL_LOG_LEVEL_DEBUG
+        ValidateTransformedSpirv(spirv, ShaderStage::TessControl, 0);
+#else
+        if (m_enableSpirvValidation) {
+            MG_Util::ShaderTranspiler::ShaderCompiler::PrepareSpirvValidation();
+            ValidateTransformedSpirv(spirv, ShaderStage::TessControl, 0);
+        }
+#endif
+
+        VkShaderModuleCreateInfo smci{VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO};
+        smci.codeSize = spirv.size() * sizeof(Uint);
+        smci.pCode = spirv.data();
+        VkShaderModule module = VK_NULL_HANDLE;
+        const VkResult result = vkCreateShaderModule(m_device, &smci, nullptr, &module);
+        if (result != VK_SUCCESS) {
+            MGLOG_E("ProgramFactory: vkCreateShaderModule failed (%d) for the pass-through tessellation control "
+                    "stage for patchVertices=%u", static_cast<Int>(result), patchVertices);
+            m_passthroughTessControlStages.emplace(patchVertices, stage);
+            return stage;
+        }
+
+        stage.module = module;
+        MGLOG_D("ProgramFactory: built the pass-through tessellation control stage for patchVertices=%u "
+                "(GL 4.6 11.2.2; Vulkan has no fixed-function equivalent)", patchVertices);
+        m_passthroughTessControlStages.emplace(patchVertices, stage);
+        return stage;
+    }
+
+    void ProgramFactory::ReflectPassthroughTessControlNeed(
+        const Vector<ShaderStage>& stages,
+        const Vector<Vector<Uint>>& spirv,
+        VkProgramObject& entry) const {
+        entry.needsPassthroughTessControl = false;
+        entry.passthroughTessControlEmulatable = false;
+
+        Bool hasTessEval = false;
+        Bool hasTessControl = false;
+        SizeT tessEvalModuleIndex = 0;
+        for (SizeT i = 0; i < stages.size(); ++i) {
+            const ShaderStage stage = stages[i];
+            if (stage == ShaderStage::TessControl) hasTessControl = true;
+            if (stage == ShaderStage::TessEval) {
+                hasTessEval = true;
+                tessEvalModuleIndex = i;
+            }
+        }
+        if (!hasTessEval || hasTessControl) return;
+
+        entry.needsPassthroughTessControl = true;
+
+        if (tessEvalModuleIndex >= spirv.size() || spirv[tessEvalModuleIndex].empty()) return;
+        const auto& module = spirv[tessEvalModuleIndex];
+
+        SpvReflectShaderModule reflectModule{};
+        const SpvReflectResult createResult =
+            spvReflectCreateShaderModule(module.size() * sizeof(Uint), module.data(), &reflectModule);
+        if (createResult != SPV_REFLECT_RESULT_SUCCESS) {
+            MGLOG_E("ProgramFactory::ReflectPassthroughTessControlNeed: reflection failed (result=%d); the "
+                    "evaluation stage's inputs are unknown, so the pass-through is not offered",
+                    static_cast<Int>(createResult));
+            return;
+        }
+
+        uint32_t inputCount = 0;
+        SpvReflectResult reflectResult = spvReflectEnumerateInputVariables(&reflectModule, &inputCount, nullptr);
+        Vector<SpvReflectInterfaceVariable*> inputs(inputCount);
+        if (reflectResult == SPV_REFLECT_RESULT_SUCCESS && inputCount > 0) {
+            reflectResult = spvReflectEnumerateInputVariables(&reflectModule, &inputCount, inputs.data());
+        }
+        if (reflectResult != SPV_REFLECT_RESULT_SUCCESS) {
+            spvReflectDestroyShaderModule(&reflectModule);
+            return;
+        }
+
+        // The question is only ever "does this stage read anything a control stage would have to
+        // forward", and the answer is: does it have a LOCATION. A located input is a user-defined
+        // varying (or a per-patch input), which the vertex stage writes today and would stop
+        // reaching once a control stage sits in between - the pass-through carries gl_Position and
+        // nothing else, so such a program is declined instead of being handed undefined values.
+        // Everything without a location is a built-in: gl_in, gl_TessCoord, gl_PatchVerticesIn,
+        // gl_PrimitiveID, gl_TessLevel*, all either forwarded or generated for the evaluation
+        // stage by the tessellator itself.
+        //
+        // This deliberately does NOT judge on SpvReflectInterfaceVariable::built_in. gl_in is an
+        // array of interface blocks, and for those SPIRV-Reflect reports built_in == -1 on the
+        // block AND leaves every member's built_in at 0 - which is SpvBuiltInPosition, so a
+        // member walk reads "Position, Position, Position" for a {Position, PointSize,
+        // ClipDistance} block and would accept anything on the strength of parse garbage. The
+        // location, by contrast, is decorated on the OpVariable and is what SPIRV-Reflect reads
+        // straight through.
+        constexpr Uint32 kNoLocation = 0xFFFFFFFFu;
+        Bool emulatable = true;
+        for (auto* input : inputs) {
+            if (input == nullptr) continue;
+            if (input->location == kNoLocation) continue;
+            MGLOG_E("ProgramFactory: a tessellation evaluation stage with no control stage reads the "
+                    "user-defined input '%s' at location=%u; a synthesized control stage cannot forward it, so "
+                    "this program's draws are declined rather than fed an undefined varying",
+                    input->name != nullptr ? input->name : "<null>", input->location);
+            emulatable = false;
+            break;
+        }
+
+        spvReflectDestroyShaderModule(&reflectModule);
+        entry.passthroughTessControlEmulatable = emulatable;
+    }
 } // namespace MobileGL::MG_Backend::DirectVulkan

MobileGL/MG_Backend/DirectVulkan/Renderer/ProgramFactory.h

@@ -76,6 +76,23 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         using CompileOptionFlags = Flags<CompileOptionBit>;
         using HashType = Uint64;
 
+        struct UpdateAfterBindLimits {
+            Bool enabled = false;
+            Uint32 maxPerStageSamplers = 0;
+            Uint32 maxPerStageUniformBuffers = 0;
+            Uint32 maxPerStageStorageBuffers = 0;
+            Uint32 maxPerStageSampledImages = 0;
+            Uint32 maxPerStageStorageImages = 0;
+            Uint32 maxPerStageResources = 0;
+            Uint32 maxSetSamplers = 0;
+            Uint32 maxSetUniformBuffers = 0;
+            Uint32 maxSetUniformBuffersDynamic = 0;
+            Uint32 maxSetStorageBuffers = 0;
+            Uint32 maxSetStorageBuffersDynamic = 0;
+            Uint32 maxSetSampledImages = 0;
+            Uint32 maxSetStorageImages = 0;
+        };
+
         struct VkProgramObject {
             static constexpr Uint32 kMaxVertexInputLocations = 32;
 
@@ -88,6 +105,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
             // Layout data (previously in separate VkProgramLayout)
             VkDescriptorSetLayout descriptorSetLayout = VK_NULL_HANDLE;
+            // True only when this layout passed every descriptor-indexing feature and
+            // update-after-bind limit gate at reflection time. It controls both the
+            // layout/binding flags and the pool class used by UniformManager.
+            Bool usesUpdateAfterBind = false;
             VkPipelineLayout pipelineLayout = VK_NULL_HANDLE;
             Vector<DescriptorBindingKind> bindingKinds;
             // The bindings this program actually declares, ascending. bindingKinds is sized to the
@@ -151,6 +172,28 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // PROGRAM rather than of the variant: the zeroed variant leaves the variable
             // declared, so both variants answer the same and the draw path can ask either.
             Bool readsBaseVertexBuiltin = false;
+            // Some pre-rasterization stage assigns gl_ViewportIndex. Its pipeline declares
+            // viewportCount = the renderer's rasterizable viewport count instead of 1, and its
+            // draws push the whole viewport/scissor array; every other program keeps the
+            // single-viewport fast path untouched. Part of the program's identity (folded into
+            // the pipeline hash through programHash), so no memo can serve the wrong shape.
+            Bool writesViewportIndexBuiltin = false;
+            // This program has a tessellation EVALUATION stage and no tessellation CONTROL
+            // stage. GL allows that (4.6 core 11.2.2: with no control shader the input patch
+            // is passed through unmodified, the output patch size is PATCH_VERTICES, and the
+            // levels come from the PATCH_DEFAULT_*_LEVEL state); Vulkan does not - either both
+            // tessellation stages are present or neither
+            // (VUID-VkGraphicsPipelineCreateInfo-pStages-00730). So the draw path has to supply
+            // the pass-through stage GL describes; see GetOrCreatePassthroughTessControlStage.
+            Bool needsPassthroughTessControl = false;
+            // ...and the pass-through this renderer can synthesize carries gl_Position and
+            // nothing else, so it is only correct when the evaluation stage's inputs are
+            // built-ins. A user-defined varying would arrive at the evaluation stage
+            // UNWRITTEN once a control stage sits between it and the vertex stage, which is
+            // silently wrong pixels rather than a crash - so those programs are declined
+            // instead (PipelineFactory::CreatePipeline refuses the pipeline and the draw is
+            // skipped). See ReflectPassthroughTessControlNeed.
+            Bool passthroughTessControlEmulatable = false;
             // Frame-boundary counter value of the last GetOrCreateProgram hit; drives
             // cache eviction (see OnFrameBoundary). Mutable: the draw snapshot's memoised
             // entry pointer re-stamps use through a const reference (StampProgramUse).
@@ -174,6 +217,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 // a pipeline failure would be reported against the wrong SPIR-V.
                 stageSpirvDigests = std::move(other.stageSpirvDigests);
                 descriptorSetLayout = other.descriptorSetLayout;
+                usesUpdateAfterBind = other.usesUpdateAfterBind;
                 pipelineLayout = other.pipelineLayout;
                 bindingKinds = std::move(other.bindingKinds);
                 activeBindings = std::move(other.activeBindings);
@@ -202,9 +246,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 fragmentInputComponentCount = other.fragmentInputComponentCount;
                 fragmentReplacesDepth = other.fragmentReplacesDepth;
                 readsBaseVertexBuiltin = other.readsBaseVertexBuiltin;
+                writesViewportIndexBuiltin = other.writesViewportIndexBuiltin;
+                needsPassthroughTessControl = other.needsPassthroughTessControl;
+                passthroughTessControlEmulatable = other.passthroughTessControlEmulatable;
                 lastUsedFrame = other.lastUsedFrame;
                 other.hash = 0;
                 other.descriptorSetLayout = VK_NULL_HANDLE;
+                other.usesUpdateAfterBind = false;
                 other.pipelineLayout = VK_NULL_HANDLE;
                 other.hasStorageImages = false;
                 other.declinedDescriptors = false;
@@ -216,6 +264,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 other.fragmentInputComponentCount = 0;
                 other.fragmentReplacesDepth = false;
                 other.readsBaseVertexBuiltin = false;
+                other.writesViewportIndexBuiltin = false;
+                other.needsPassthroughTessControl = false;
+                other.passthroughTessControlEmulatable = false;
                 other.lastUsedFrame = 0;
             }
             VkProgramObject& operator=(VkProgramObject&& other) noexcept {
@@ -228,6 +279,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 modules = std::move(other.modules);
                 stageSpirvDigests = std::move(other.stageSpirvDigests); // travels with `modules` - see the move ctor
                 descriptorSetLayout = other.descriptorSetLayout;
+                usesUpdateAfterBind = other.usesUpdateAfterBind;
                 pipelineLayout = other.pipelineLayout;
                 bindingKinds = std::move(other.bindingKinds);
                 activeBindings = std::move(other.activeBindings);
@@ -256,9 +308,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 fragmentInputComponentCount = other.fragmentInputComponentCount;
                 fragmentReplacesDepth = other.fragmentReplacesDepth;
                 readsBaseVertexBuiltin = other.readsBaseVertexBuiltin;
+                writesViewportIndexBuiltin = other.writesViewportIndexBuiltin;
+                needsPassthroughTessControl = other.needsPassthroughTessControl;
+                passthroughTessControlEmulatable = other.passthroughTessControlEmulatable;
                 lastUsedFrame = other.lastUsedFrame;
                 other.hash = 0;
                 other.descriptorSetLayout = VK_NULL_HANDLE;
+                other.usesUpdateAfterBind = false;
                 other.pipelineLayout = VK_NULL_HANDLE;
                 other.hasStorageImages = false;
                 other.declinedDescriptors = false;
@@ -270,6 +326,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 other.fragmentInputComponentCount = 0;
                 other.fragmentReplacesDepth = false;
                 other.readsBaseVertexBuiltin = false;
+                other.writesViewportIndexBuiltin = false;
+                other.needsPassthroughTessControl = false;
+                other.passthroughTessControlEmulatable = false;
                 other.lastUsedFrame = 0;
                 return *this;
             }
@@ -313,15 +372,45 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             virtual void OnProgramEvicted(HashType programHash, VkDescriptorSetLayout descriptorSetLayout) = 0;
         };
 
-        explicit ProgramFactory(VkDevice device, const VulkanRendererConfig& config, Uint32 maxBindings = 16,
-                                Bool shaderDrawParametersEnabled = false,
-                                Bool unformattedFloatStorageImagesEnabled = false)
+        // How this factory's compute modules implement GL_KHR_shader_subgroup. Computed
+        // once at renderer initialization (SubgroupSupportPolicy.h + the device's
+        // subgroup properties) so lowering can never disagree with the advertised
+        // capabilities. Native subgroup operations always execute natively; the two
+        // repair passes patch modules AROUND them, and the emulation only replaces them
+        // on opted-in devices with no subgroup support at all.
+        struct SubgroupLoweringPolicy {
+            Bool emulateSubgroups = false;      // MOBILEGL_MAGMA_EMULATE_SUBGROUP, no-native-support devices
+            Bool fixIterationRPSubgroupScratch = false; // patch iterationRP's under-declared scratch
+            Bool fixIterationRPBarrier = false; // repair Program 203's shared-scratch race
+            Bool deriveNumSubgroups = false;    // repair the NumSubgroups builtin
+            Bool requireFullSubgroups = false;  // computeFullSubgroups enabled on the device
+            Uint32 nativeSubgroupSize = 0;
+            // Full-subgroup launches are bounded by this device limit; a dispatch whose
+            // workgroup needs more subgroups than this cannot request the flag.
+            Uint32 maxComputeWorkgroupSubgroups = 0;
+            // VkPhysicalDeviceLimits::maxComputeSharedMemorySize; bounds the scratch the
+            // emulation pass may add (0 falls back to the Vulkan minimum, 16384).
+            Uint32 maxComputeSharedMemoryBytes = 0;
+        };
+
+        explicit ProgramFactory(VkDevice device, const VulkanRendererConfig& config, Uint32 maxBindings,
+                                Bool shaderDrawParametersEnabled,
+                                Bool unformattedFloatStorageImagesEnabled,
+                                Bool enableSpirvValidation,
+                                UpdateAfterBindLimits updateAfterBindLimits,
+                                SubgroupLoweringPolicy subgroupPolicy)
             : m_device(device), m_maxBindings(maxBindings), m_config(config),
               m_shaderDrawParametersEnabled(shaderDrawParametersEnabled),
-              m_unformattedFloatStorageImagesEnabled(unformattedFloatStorageImagesEnabled) {
+              m_unformattedFloatStorageImagesEnabled(unformattedFloatStorageImagesEnabled),
+              m_enableSpirvValidation(enableSpirvValidation),
+              m_updateAfterBindLimits(updateAfterBindLimits),
+              m_subgroupPolicy(subgroupPolicy) {
             VkProgramObject::s_device = device;
         }
-        ~ProgramFactory() = default;
+        // Destroys the pass-through tessellation control modules. Runs while the device is
+        // still alive for the same reason ~VkProgramObject's does: this factory outlives
+        // nothing that owns the device.
+        ~ProgramFactory();
         ProgramFactory(const ProgramFactory&) = delete;
 
         HashType ComputeHash(const MG_State::GLState::ProgramObject& program, CompileOptionFlags flags) const;
@@ -373,6 +462,33 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // Shared by the two above: does any entry point list an input variable decorated with
         // this builtin?
         static Bool ReflectedDeclaresInputBuiltin(const SpvReflectShaderModule& reflectModule, SpvBuiltIn builtin);
+        // True when an entry point writes the ViewportIndex builtin (gl_ViewportIndex), i.e. when
+        // the program can route primitives to a viewport other than 0 and its pipeline therefore
+        // has to declare more than one. Asks about OUTPUT variables because that is the direction
+        // a pre-rasterization stage declares it in.
+        static Bool ReflectedWritesViewportIndexBuiltin(const SpvReflectShaderModule& reflectModule);
+        static Bool ReflectedDeclaresOutputBuiltin(const SpvReflectShaderModule& reflectModule, SpvBuiltIn builtin);
+
+        // The pass-through tessellation control stage GL 4.6 core 11.2.2 describes for a
+        // program that has an evaluation stage and no control stage, for an input patch of
+        // `patchVertices` control points. Returned BY VALUE (a stage description is a POD, and
+        // the cache below is a rehashing map, so a pointer into it would not survive the next
+        // distinct patch size). `.module == VK_NULL_HANDLE` means the stage could not be built:
+        // the caller then has no control stage to inject, and CreatePipeline refuses the
+        // pipeline rather than handing the driver a half-tessellated one.
+        //
+        // Keyed on the patch size because GL takes the output patch size from PATCH_VERTICES,
+        // which is draw state, not link state - the CTS case that motivated this links at the
+        // default 3 and draws at 4. The pipeline cache already re-keys on patchControlPoints,
+        // so the module a pipeline was built with is part of that pipeline's identity.
+        // Compiling is bounded by the number of distinct patch sizes a program draws with
+        // (MAX_PATCH_VERTICES = 32 in the worst case, one or two in practice) and only ever
+        // happens for the rare program that has no control stage at all.
+        VkPipelineShaderStageCreateInfo GetOrCreatePassthroughTessControlStage(Uint32 patchVertices);
+
+        // Source of the module above. Exposed for tests: the generated GLSL is the whole
+        // contract with the evaluation stage, so it is worth pinning independently of a device.
+        static String BuildPassthroughTessControlSource(Uint32 patchVertices);
 
     private:
         struct ProgramLookupCache {
@@ -383,14 +499,27 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         };
 
         static TextureTarget UniformTypeToTextureTarget(GLenum glType);
-        void ReflectVertexInputs(const Vector<SharedPtr<MG_State::GLState::ShaderObject>>& shaders,
+        // `stages` is ALWAYS ProgramObject::GetLinkedShaderStages() - one entry per module of
+        // `spirv`, at the same index. Taking the stages rather than the shader objects is what
+        // keeps the program's live attach list, which is a longer and differently-indexed list
+        // the moment a glAttachShader lands after the link, from being passed here by mistake.
+        void ReflectVertexInputs(const Vector<ShaderStage>& stages,
                      const Vector<Vector<Uint>>& spirv,
                      VkProgramObject& entry) const;
-        void ReflectFragmentOutputs(const Vector<SharedPtr<MG_State::GLState::ShaderObject>>& shaders,
+        void ReflectViewportIndexUsage(const Vector<ShaderStage>& stages,
+                                       const Vector<Vector<Uint>>& spirv,
+                                       VkProgramObject& entry) const;
+        void ReflectFragmentOutputs(const Vector<ShaderStage>& stages,
                         const Vector<Vector<Uint>>& spirv,
                         VkProgramObject& entry) const;
         void ReflectLayout(const MG_State::GLState::ProgramObject& program, const Vector<Vector<Uint>>& spirv,
                            VkProgramObject& entry) const;
+        // Fills needsPassthroughTessControl / passthroughTessControlEmulatable off the linked
+        // modules. Const and reflection-only: it decides nothing about the pipeline, it only
+        // records what the evaluation stage's input interface is made of.
+        void ReflectPassthroughTessControlNeed(const Vector<ShaderStage>& stages,
+                                               const Vector<Vector<Uint>>& spirv,
+                                               VkProgramObject& entry) const;
 
         VkDevice m_device = VK_NULL_HANDLE;
         Uint32 m_maxBindings = 0;
@@ -402,6 +531,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // True only when the logical device enabled both
         // shaderStorageImageReadWithoutFormat and shaderStorageImageWriteWithoutFormat.
         Bool m_unformattedFloatStorageImagesEnabled = false;
+        // Startup snapshot used only by internally synthesized shader modules, which do not
+        // originate from a ProgramLinkTask.
+        Bool m_enableSpirvValidation = false;
+        // Device feature and limit gate resolved before vkCreateDevice. Keeping it in
+        // the factory lets each reflected layout choose ordinary descriptors when its
+        // own counts would exceed the update-after-bind budget.
+        UpdateAfterBindLimits m_updateAfterBindLimits{};
+        SubgroupLoweringPolicy m_subgroupPolicy{};
         // See SetDefaultFramebufferHeight. 0 means "not known yet"; the FragCoordYFlip bit is
         // never set before the swapchain exists, so no variant can be compiled against it.
         Uint32 m_defaultFramebufferHeight = 0;
@@ -411,6 +548,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // See GetCacheStructureEpoch(). Starts at 1 so a zero-initialized memo can never match.
         Uint64 m_cacheStructureEpoch = 1;
         IEvictionObserver* m_evictionObserver = nullptr;
+        // Pass-through tessellation control stages by input patch size. Never evicted: at most
+        // MAX_PATCH_VERTICES entries exist for the lifetime of the device, and every pipeline
+        // ever built from one keeps referencing its module. A failed build is cached as
+        // VK_NULL_HANDLE so a broken generator costs one compile, not one per draw.
+        UnorderedMap<Uint32, VkPipelineShaderStageCreateInfo> m_passthroughTessControlStages;
         static inline XXH64_state_t* m_hashState = XXH64_createState();
     };
 } // namespace MobileGL::MG_Backend::DirectVulkan

MobileGL/MG_Backend/DirectVulkan/Renderer/SwapchainObject.cpp

@@ -157,7 +157,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         MGLOG_I("Got %d surface formats:", swapchainCapabilities.surfaceFormats.size());
         for (const auto& sf : swapchainCapabilities.surfaceFormats) {
-            MGLOG_I("    [%s, %s]", string_VkFormat(sf.format), string_VkColorSpaceKHR(sf.colorSpace));
+            MGLOG_D("    [%s, %s]", string_VkFormat(sf.format), string_VkColorSpaceKHR(sf.colorSpace));
         }
 
         const auto pickedSurfaceFormat = ChooseSwapchainSurfaceFormat(swapchainCapabilities.surfaceFormats);
@@ -166,7 +166,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         MGLOG_I("Got %d present modes:", swapchainCapabilities.presentModes.size());
         for (const auto& pm : swapchainCapabilities.presentModes) {
-            MGLOG_I("    %s", string_VkPresentModeKHR(pm));
+            MGLOG_D("    %s", string_VkPresentModeKHR(pm));
         }
 
         const auto presentMode = ChooseSwapchainPresentMode(swapchainCapabilities.presentModes);

MobileGL/MG_Backend/DirectVulkan/Renderer/UniformManager.cpp

@@ -156,13 +156,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             frame.descriptorPools.clear();
 
             VkDescriptorPool initialPool = VK_NULL_HANDLE;
-            if (!CreateDescriptorPool(m_setsPerFrame, initialPool)) {
-                MGLOG_E("UniformDescriptorBinder::Initialize failed: cannot create frame descriptor pool %u",
+            if (!CreateDescriptorPool(m_setsPerFrame, false, initialPool)) {
+                MGLOG_E_ONCE("UniformDescriptorBinder::Initialize failed: cannot create frame descriptor pool %u",
                         frameIndex);
                 Shutdown();
                 return false;
             }
-            frame.descriptorPools.push_back({initialPool, m_setsPerFrame, 0});
+            frame.descriptorPools.push_back({initialPool, m_setsPerFrame, 0, false});
             MGLOG_D("UniformDescriptorBinder: frame %u descriptor pool created (maxSets=%u)", frameIndex,
                     m_setsPerFrame);
         }
@@ -305,7 +305,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // texture/sampler resolution, completeness probe, sync, layout handling, sampler
         // and view lookups - would recompute the identical descriptor.
         if (trustUnchangedHint && descriptorMemoUsable && binding < m_samplerResolveMemo.size() &&
-            m_samplerResolveMemo[binding].infoValid) {
+            m_samplerResolveMemo[binding].infoValid &&
+            m_samplerResolveMemo[binding].infoProgramLifetimeId == program.GetLifetimeId()) {
             outImageInfo = m_samplerResolveMemo[binding].info;
             return true;
         }
@@ -345,13 +346,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             fallbackHolder = GetFallbackTexture(preferredTarget);
             texture = fallbackHolder.get();
             if (texture == nullptr) {
-                MGLOG_E("ResolveSamplerDescriptor: no fallback texture available for binding=%u ('%s') "
+                MGLOG_E_ONCE("ResolveSamplerDescriptor: no fallback texture available for binding=%u ('%s') "
                         "location=%d unit=%d target=%d",
                         binding, programObj.samplerNameByBinding[binding].c_str(), location, unit,
                         static_cast<Int>(preferredTarget));
                 return false;
             }
-            MGLOG_W(
+            MGLOG_W_ONCE(
                 "ResolveSamplerDescriptor: using fallback texture for unbound sampler binding=%u ('%s') location=%d unit=%d target=%d",
                 binding, programObj.samplerNameByBinding[binding].c_str(), location, unit,
                 static_cast<Int>(preferredTarget));
@@ -360,7 +361,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const MG_State::GLState::SamplerObject* samplerToUse =
             samplerOverride ? samplerOverride.get() : texture->GetSamplerObject().get();
         if (samplerToUse == nullptr) {
-            MGLOG_E(
+            MGLOG_E_ONCE(
                 "ResolveSamplerDescriptor: sampler binding %u ('%s') has no sampler object (textureId=%d location=%d unit=%d)",
                 binding, programObj.samplerNameByBinding[binding].c_str(), texture->GetExternalIndex(), location,
                 unit);
@@ -368,7 +369,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
         VkTextureManager::TextureResource* resource = m_textureManager->SyncTextureAndGetDescriptor(*texture);
         if (resource == nullptr) {
-            MGLOG_E(
+            MGLOG_E_ONCE(
                 "ResolveSamplerDescriptor: sampler binding %u ('%s') failed to create/sync texture resource (textureId=%d target=%d location=%d unit=%d)",
                 binding, programObj.samplerNameByBinding[binding].c_str(), texture->GetExternalIndex(),
                 static_cast<Int>(texture->GetTarget()), location, unit);
@@ -380,7 +381,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             Int attachmentLevel = 0;
             if (drawFbo &&
                 FindFramebufferAttachmentForTexture(*drawFbo, *texture, attachmentType, attachmentLevel)) {
-                MGLOG_W("ResolveSamplerDescriptor: framebuffer feedback loop detected: textureId=%d is bound "
+                MGLOG_W_ONCE("ResolveSamplerDescriptor: framebuffer feedback loop detected: textureId=%d is bound "
                         "for sampling at binding=%u, but is also attached to drawFbo=%u as %s (level=%d, "
                         "trackedLayout=%d)",
                         texture->GetExternalIndex(), binding, drawFbo->GetExternalIndex(),
@@ -390,7 +391,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
             const Bool readyForSampling = m_textureManager->TransitionTextureForSampling(commandBuffer, *texture);
             if (!readyForSampling) {
-                MGLOG_E("ResolveSamplerDescriptor: failed to transition textureId=%d for sampler binding=%u",
+                MGLOG_E_ONCE("ResolveSamplerDescriptor: failed to transition textureId=%d for sampler binding=%u",
                         texture->GetExternalIndex(), binding);
                 return false;
             }
@@ -432,7 +433,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             }
         }
         if (sampledViewFormat == VK_FORMAT_UNDEFINED) {
-            MGLOG_E("ResolveSamplerDescriptor: no compatible sampled view for binding=%u ('%s') "
+            MGLOG_E_ONCE("ResolveSamplerDescriptor: no compatible sampled view for binding=%u ('%s') "
                     "textureId=%d imageFormat=%d numericDomain=%d",
                     binding, programObj.samplerNameByBinding[binding].c_str(), texture->GetExternalIndex(),
                     static_cast<Int>(resource->format), static_cast<Int>(numericDomain));
@@ -445,7 +446,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 ? resource->sampledView
                 : m_textureManager->GetOrCreateSampledImageView(*texture, sampledViewFormat);
         if (sampledImageView == VK_NULL_HANDLE) {
-            MGLOG_E("ResolveSamplerDescriptor: failed to resolve sampled view for binding=%u ('%s') "
+            MGLOG_E_ONCE("ResolveSamplerDescriptor: failed to resolve sampled view for binding=%u ('%s') "
                     "textureId=%d imageFormat=%d viewFormat=%d numericDomain=%d",
                     binding, programObj.samplerNameByBinding[binding].c_str(), texture->GetExternalIndex(),
                     static_cast<Int>(resource->format), static_cast<Int>(sampledViewFormat),
@@ -504,6 +505,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         if (binding < m_samplerResolveMemo.size()) {
             if (descriptorMemoUsable) {
                 m_samplerResolveMemo[binding].info = outImageInfo;
+                m_samplerResolveMemo[binding].infoProgramLifetimeId = program.GetLifetimeId();
                 m_samplerResolveMemo[binding].infoValid = true;
             } else {
                 // An arrayed binding publishes nothing here, and clears what a previous program
@@ -540,11 +542,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         outImageInfo = {
             .sampler = m_samplerManager->GetOrCreateSampler(*samplerBindingOverride.sampler,
-                                                            *samplerBindingOverride.texture),
+                                                            *samplerBindingOverride.texture,
+                                                            samplerBindingOverride.forceNearestFiltering,
+                                                            resource->sampledLevelCount),
             .imageView = samplerBindingOverride.imageView != VK_NULL_HANDLE ?
                 samplerBindingOverride.imageView :
                 (resource->sampledView != VK_NULL_HANDLE ? resource->sampledView : resource->fullView),
-            .imageLayout = resource->layout,
+            .imageLayout = samplerBindingOverride.imageLayout != VK_IMAGE_LAYOUT_UNDEFINED ?
+                samplerBindingOverride.imageLayout : resource->layout,
         };
         return outImageInfo.sampler != VK_NULL_HANDLE;
     }
@@ -671,14 +676,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         SharedPtr<MG_State::GLState::ITextureObject> texture;
         if (!ResolveSamplerTexture(program, programObj, binding, texture) || texture == nullptr) {
-            MGLOG_E("ResolveTexelBufferDescriptor: texture buffer binding %u ('%s') is unbound", binding,
+            MGLOG_E_ONCE("ResolveTexelBufferDescriptor: texture buffer binding %u ('%s') is unbound", binding,
                     programObj.samplerNameByBinding[binding].c_str());
             return false;
         }
 
         if (texture->GetStorageType() != TextureStorageType::Buffer ||
             texture->GetTarget() != TextureTarget::TextureBuffer) {
-            MGLOG_E(
+            MGLOG_E_ONCE(
                 "ResolveTexelBufferDescriptor: binding %u ('%s') expected texture buffer, got textureId=%u target=%d storage=%d",
                 binding, programObj.samplerNameByBinding[binding].c_str(), texture->GetExternalIndex(),
                 static_cast<Int>(texture->GetTarget()), static_cast<Int>(texture->GetStorageType()));
@@ -688,14 +693,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         auto* textureBuffer = static_cast<MG_State::GLState::TextureObjectBuffer*>(texture.get());
         const auto& bufferObject = textureBuffer->GetBufferBindingSlot().GetBoundObject();
         if (bufferObject == nullptr) {
-            MGLOG_E("ResolveTexelBufferDescriptor: texture buffer binding %u ('%s') has no GL buffer bound",
+            MGLOG_E_ONCE("ResolveTexelBufferDescriptor: texture buffer binding %u ('%s') has no GL buffer bound",
                     binding, programObj.samplerNameByBinding[binding].c_str());
             return false;
         }
 
         BufferSlice slice{};
         if (!m_bufferManager->AcquireResidentSlice(BufferKind::TextureBuffer, bufferObject, slice) || !slice.IsValid()) {
-            MGLOG_E("ResolveTexelBufferDescriptor: failed to sync GL buffer %u for texture buffer %u",
+            MGLOG_E_ONCE("ResolveTexelBufferDescriptor: failed to sync GL buffer %u for texture buffer %u",
                     bufferObject->GetExternalIndex(), texture->GetExternalIndex());
             return false;
         }
@@ -703,7 +708,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const auto internalFormat = textureBuffer->GetFormat();
         const VkFormat vkFormat = MG_Util::ConvertTextureInternalFormatToVkEnum(internalFormat);
         if (vkFormat == VK_FORMAT_UNDEFINED) {
-            MGLOG_E("ResolveTexelBufferDescriptor: unsupported texture buffer internal format %d",
+            MGLOG_E_ONCE("ResolveTexelBufferDescriptor: unsupported texture buffer internal format %d",
                     static_cast<Int>(internalFormat));
             return false;
         }
@@ -719,7 +724,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             viewRange = (viewRange / texelSize) * texelSize;
         }
         if (viewRange == 0) {
-            MGLOG_E("ResolveTexelBufferDescriptor: texture buffer %u has empty view range", texture->GetExternalIndex());
+            MGLOG_E_ONCE("ResolveTexelBufferDescriptor: texture buffer %u has empty view range", texture->GetExternalIndex());
             return false;
         }
 
@@ -733,7 +738,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         VkBufferView bufferView = VK_NULL_HANDLE;
         const VkResult result = vkCreateBufferView(m_device, &viewInfo, nullptr, &bufferView);
         if (result != VK_SUCCESS || bufferView == VK_NULL_HANDLE) {
-            MGLOG_E("ResolveTexelBufferDescriptor: vkCreateBufferView failed result=%d format=%d range=%zu",
+            MGLOG_E_ONCE("ResolveTexelBufferDescriptor: vkCreateBufferView failed result=%d format=%d range=%zu",
                     result, static_cast<Int>(vkFormat), static_cast<SizeT>(viewRange));
             return false;
         }
@@ -769,13 +774,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         const Int location = programObj.samplerUniformLocationByBinding[binding];
         if (location < 0) {
-            MGLOG_E("ResolveStorageTexelBufferDescriptor: binding %u ('%s') has no uniform location", binding,
+            MGLOG_E_ONCE("ResolveStorageTexelBufferDescriptor: binding %u ('%s') has no uniform location", binding,
                     programObj.samplerNameByBinding[binding].c_str());
             return false;
         }
         const Int imageUnit = program.GetUniformSamplerOrImageUnitIndex(static_cast<Uint>(location));
         if (imageUnit < 0 || imageUnit >= MG_State::GLState::TextureState::MAX_TEXTURE_IMAGE_UNITS) {
-            MGLOG_E("ResolveStorageTexelBufferDescriptor: image unit %d out of range for binding %u", imageUnit,
+            MGLOG_E_ONCE("ResolveStorageTexelBufferDescriptor: image unit %d out of range for binding %u", imageUnit,
                     binding);
             return false;
         }
@@ -783,13 +788,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         auto& imageBinding = MG_State::pGLContext->GetImageTextureBinding(imageUnit);
         const auto& texture = imageBinding.Texture;
         if (texture == nullptr) {
-            MGLOG_E("ResolveStorageTexelBufferDescriptor: image unit %d is unbound for binding %u", imageUnit,
+            MGLOG_E_ONCE("ResolveStorageTexelBufferDescriptor: image unit %d is unbound for binding %u", imageUnit,
                     binding);
             return false;
         }
         if (texture->GetStorageType() != TextureStorageType::Buffer ||
             texture->GetTarget() != TextureTarget::TextureBuffer) {
-            MGLOG_E("ResolveStorageTexelBufferDescriptor: binding %u ('%s') expected a texture buffer on image "
+            MGLOG_E_ONCE("ResolveStorageTexelBufferDescriptor: binding %u ('%s') expected a texture buffer on image "
                     "unit %d, got textureId=%u target=%d storage=%d",
                     binding, programObj.samplerNameByBinding[binding].c_str(), imageUnit,
                     texture->GetExternalIndex(), static_cast<Int>(texture->GetTarget()),
@@ -800,7 +805,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         auto* textureBuffer = static_cast<MG_State::GLState::TextureObjectBuffer*>(texture.get());
         const auto& bufferObject = textureBuffer->GetBufferBindingSlot().GetBoundObject();
         if (bufferObject == nullptr) {
-            MGLOG_E("ResolveStorageTexelBufferDescriptor: texture buffer on image unit %d has no GL buffer bound",
+            MGLOG_E_ONCE("ResolveStorageTexelBufferDescriptor: texture buffer on image unit %d has no GL buffer bound",
                     imageUnit);
             return false;
         }
@@ -819,7 +824,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         BufferSlice slice{};
         if (!m_bufferManager->AcquireResidentSlice(BufferKind::TextureBuffer, bufferObject, slice) ||
             !slice.IsValid()) {
-            MGLOG_E("ResolveStorageTexelBufferDescriptor: failed to sync GL buffer %u for texture buffer %u",
+            MGLOG_E_ONCE("ResolveStorageTexelBufferDescriptor: failed to sync GL buffer %u for texture buffer %u",
                     bufferObject->GetExternalIndex(), texture->GetExternalIndex());
             return false;
         }
@@ -842,7 +847,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             vkFormat = resourceFormat;
         }
         if (vkFormat == VK_FORMAT_UNDEFINED) {
-            MGLOG_E("ResolveStorageTexelBufferDescriptor: unsupported image buffer format (internal=%d bind=0x%x)",
+            MGLOG_E_ONCE("ResolveStorageTexelBufferDescriptor: unsupported image buffer format (internal=%d bind=0x%x)",
                     static_cast<Int>(internalFormat), imageBinding.Format);
             return false;
         }
@@ -862,7 +867,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             viewRange = (viewRange / texelSize) * texelSize;
         }
         if (viewRange == 0) {
-            MGLOG_E("ResolveStorageTexelBufferDescriptor: texture buffer %u has empty view range",
+            MGLOG_E_ONCE("ResolveStorageTexelBufferDescriptor: texture buffer %u has empty view range",
                     texture->GetExternalIndex());
             return false;
         }
@@ -877,7 +882,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         VkBufferView bufferView = VK_NULL_HANDLE;
         const VkResult result = vkCreateBufferView(m_device, &viewInfo, nullptr, &bufferView);
         if (result != VK_SUCCESS || bufferView == VK_NULL_HANDLE) {
-            MGLOG_E("ResolveStorageTexelBufferDescriptor: vkCreateBufferView failed result=%d format=%d range=%zu",
+            MGLOG_E_ONCE("ResolveStorageTexelBufferDescriptor: vkCreateBufferView failed result=%d format=%d range=%zu",
                     result, static_cast<Int>(vkFormat), static_cast<SizeT>(viewRange));
             return false;
         }
@@ -914,7 +919,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         auto& bindingPoint = MG_State::pGLContext->GetBufferBindingPoint(BufferTarget::ShaderStorage, frontendBinding);
         const auto& bufferObject = bindingPoint.GetBoundObject();
         if (bufferObject == nullptr) {
-            MGLOG_E("ResolveStorageBufferDescriptor: no SSBO bound at frontend binding %u for block '%s'",
+            MGLOG_E_ONCE("ResolveStorageBufferDescriptor: no SSBO bound at frontend binding %u for block '%s'",
                     frontendBinding, programObj.storageBlockNameByBinding[binding].c_str());
             return false;
         }
@@ -929,7 +934,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         BufferSlice slice{};
         if (!m_bufferManager->AcquireResidentSlice(BufferKind::ShaderStorage, bufferObject, slice) || !slice.IsValid()) {
-            MGLOG_E("ResolveStorageBufferDescriptor: failed to sync GL buffer %u for block '%s'",
+            MGLOG_E_ONCE("ResolveStorageBufferDescriptor: failed to sync GL buffer %u for block '%s'",
                     bufferObject->GetExternalIndex(), programObj.storageBlockNameByBinding[binding].c_str());
             return false;
         }
@@ -943,7 +948,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             rangeEnd = bufferSize;
         }
         if (rangeEnd <= rangeStart) {
-            MGLOG_E("ResolveStorageBufferDescriptor: empty SSBO range for block '%s'",
+            MGLOG_E_ONCE("ResolveStorageBufferDescriptor: empty SSBO range for block '%s'",
                     programObj.storageBlockNameByBinding[binding].c_str());
             return false;
         }
@@ -967,7 +972,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         const Int baseLocation = programObj.samplerUniformLocationByBinding[binding];
         if (baseLocation < 0) {
-            MGLOG_E("ResolveStorageImageDescriptor: storage image binding %u has no uniform location", binding);
+            MGLOG_E_ONCE("ResolveStorageImageDescriptor: storage image binding %u has no uniform location", binding);
             return false;
         }
         // Per ELEMENT, and this is where an image array differs from a storage-block array: GL
@@ -979,26 +984,26 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // uniform.
         const Int location = baseLocation + static_cast<Int>(element);
         if (!program.UniformLocationsAliasSameUniform(baseLocation, location)) {
-            MGLOG_E("ResolveStorageImageDescriptor: binding %u element %u is past the end of its image array",
+            MGLOG_E_ONCE("ResolveStorageImageDescriptor: binding %u element %u is past the end of its image array",
                     binding, element);
             return false;
         }
         const Int imageUnit = program.GetUniformSamplerOrImageUnitIndex(static_cast<Uint>(location));
         if (imageUnit < 0 || imageUnit >= MG_State::GLState::TextureState::MAX_TEXTURE_IMAGE_UNITS) {
-            MGLOG_E("ResolveStorageImageDescriptor: image unit %d out of range for binding %u",
+            MGLOG_E_ONCE("ResolveStorageImageDescriptor: image unit %d out of range for binding %u",
                     imageUnit, binding);
             return false;
         }
 
         auto& imageBinding = MG_State::pGLContext->GetImageTextureBinding(imageUnit);
         if (imageBinding.Texture == nullptr) {
-            MGLOG_E("ResolveStorageImageDescriptor: image unit %d is unbound for binding %u", imageUnit, binding);
+            MGLOG_E_ONCE("ResolveStorageImageDescriptor: image unit %d is unbound for binding %u", imageUnit, binding);
             return false;
         }
 
         const Bool ready = m_textureManager->TransitionTextureForStorageImage(commandBuffer, *imageBinding.Texture);
         if (!ready) {
-            MGLOG_E("ResolveStorageImageDescriptor: failed to transition textureId=%d for image unit %d",
+            MGLOG_E_ONCE("ResolveStorageImageDescriptor: failed to transition textureId=%d for image unit %d",
                     imageBinding.Texture->GetExternalIndex(), imageUnit);
             return false;
         }
@@ -1018,7 +1023,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const VkFormat viewFormat = ResolveStorageImageViewFormat(
             reflectedFormat, imageBinding.Format, resource->format, useBindingFormat);
         if (viewFormat == VK_FORMAT_UNDEFINED) {
-            MGLOG_E("ResolveStorageImageDescriptor: unsupported glBindImageTexture format=0x%x "
+            MGLOG_E_ONCE("ResolveStorageImageDescriptor: unsupported glBindImageTexture format=0x%x "
                     "for binding=%u imageUnit=%d textureId=%d bindingPolicy=%s",
                     imageBinding.Format, binding, imageUnit, imageBinding.Texture->GetExternalIndex(),
                     useBindingFormat ? "true" : "false");
@@ -1027,7 +1032,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const VkImageView view = m_textureManager->GetOrCreateStorageImageView(
             *imageBinding.Texture, mipLevel, viewFormat, imageBinding.Layered != GL_FALSE, imageBinding.Layer);
         if (view == VK_NULL_HANDLE) {
-            MGLOG_E("ResolveStorageImageDescriptor: failed to resolve storage view textureId=%d mip=%u "
+            MGLOG_E_ONCE("ResolveStorageImageDescriptor: failed to resolve storage view textureId=%d mip=%u "
                     "bindingFormat=0x%x imageFormat=%d reflectedFormat=%d selectedFormat=%d bindingPolicy=%s",
                     imageBinding.Texture->GetExternalIndex(), mipLevel, imageBinding.Format,
                     static_cast<Int>(resource->format), static_cast<Int>(reflectedFormat),
@@ -1048,7 +1053,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // Report that there is no fallback and let the caller decline the draw - aborting the
         // process over an unbound sampler is never the right answer.
         if (target != TextureTarget::Texture2D && target != TextureTarget::TextureRectangle) {
-            MGLOG_E("UniformManager::GetFallbackTexture: no fallback exists for target=%d",
+            MGLOG_E_ONCE("UniformManager::GetFallbackTexture: no fallback exists for target=%d",
                     static_cast<Int>(target));
             return nullptr;
         }
@@ -1224,13 +1229,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 continue;
             }
             if (binding >= programObj.samplerUniformLocationByBinding.size()) {
-                MGLOG_E("CollectStorageImageTextures: binding %u has no uniform-location mapping", binding);
+                MGLOG_E_ONCE("CollectStorageImageTextures: binding %u has no uniform-location mapping", binding);
                 return false;
             }
 
             const Int baseLocation = programObj.samplerUniformLocationByBinding[binding];
             if (baseLocation < 0) {
-                MGLOG_E("CollectStorageImageTextures: binding %u has no image uniform location", binding);
+                MGLOG_E_ONCE("CollectStorageImageTextures: binding %u has no image uniform location", binding);
                 return false;
             }
             // Per ELEMENT, for the same reason the sampled walk above is: an image ARRAY is one
@@ -1242,20 +1247,20 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             for (Uint32 element = 0; element < descriptorCount; ++element) {
                 const Int location = ResolveDescriptorElementLocation(program, baseLocation, element);
                 if (location < 0) {
-                    MGLOG_E("CollectStorageImageTextures: binding %u element %u is past the end of its image array",
+                    MGLOG_E_ONCE("CollectStorageImageTextures: binding %u element %u is past the end of its image array",
                             binding, element);
                     return false;
                 }
                 const Int imageUnit = program.GetUniformSamplerOrImageUnitIndex(static_cast<Uint>(location));
                 if (imageUnit < 0 || imageUnit >= MG_State::GLState::TextureState::MAX_TEXTURE_IMAGE_UNITS) {
-                    MGLOG_E("CollectStorageImageTextures: image unit %d is invalid for binding %u element %u",
+                    MGLOG_E_ONCE("CollectStorageImageTextures: image unit %d is invalid for binding %u element %u",
                             imageUnit, binding, element);
                     return false;
                 }
 
                 auto* texture = MG_State::pGLContext->GetImageTextureBinding(imageUnit).Texture.get();
                 if (texture == nullptr) {
-                    MGLOG_E("CollectStorageImageTextures: image unit %d is unbound for binding %u element %u",
+                    MGLOG_E_ONCE("CollectStorageImageTextures: image unit %d is unbound for binding %u element %u",
                             imageUnit, binding, element);
                     return false;
                 }
@@ -1267,6 +1272,87 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return true;
     }
 
+    Bool UniformManager::SamplerOverlapsWritableImageSubresource(Int samplerBaseLevel, Int samplerMaxLevel,
+                                                                 GLint imageLevel, GLenum imageAccess) {
+        return imageAccess != GL_READ_ONLY && imageLevel >= samplerBaseLevel && imageLevel <= samplerMaxLevel;
+    }
+
+    Bool UniformManager::CollectSamplerImageFeedback(
+        const MG_State::GLState::ProgramObject& program,
+        const ProgramFactory::VkProgramObject& programObj,
+        Vector<SamplerImageFeedbackBinding>& outBindings) const {
+        outBindings.clear();
+        MOBILEGL_ASSERT(MG_State::pGLContext != nullptr,
+                        "CollectSamplerImageFeedback: GL context is null");
+        if (programObj.declinedDescriptors) return true;
+
+        for (const Uint32 samplerBinding : programObj.activeBindings) {
+            if (samplerBinding >= m_maxBindings ||
+                programObj.bindingKinds[samplerBinding] != ProgramFactory::DescriptorBindingKind::CombinedImageSampler) {
+                continue;
+            }
+            const Uint32 samplerCount = BindingDescriptorCount(programObj, samplerBinding);
+            for (Uint32 samplerElement = 0; samplerElement < samplerCount; ++samplerElement) {
+                MG_State::GLState::ITextureObject* sampledTexture = nullptr;
+                const MG_State::GLState::SamplerObject* sampledSampler = nullptr;
+                if (!ResolveSampledBinding(program, programObj, samplerBinding, samplerElement,
+                                           sampledTexture, sampledSampler) ||
+                    sampledTexture == nullptr || sampledSampler == nullptr ||
+                    MG_State::GLState::SamplesAsIncompleteTexture(sampledTexture, sampledSampler)) {
+                    // ResolveSamplerDescriptor uses a fallback in these cases, which cannot
+                    // alias the image-unit binding of the original texture.
+                    continue;
+                }
+                // Multisample source images intentionally omit TRANSFER_SRC usage. Keep their existing
+                // direct binding instead of turning otherwise valid sampler2DMS/image2DMS dispatches
+                // into failed dispatches; a correct snapshot for them needs a same-sample-count path.
+                const TextureTarget sampledTarget = sampledTexture->GetTarget();
+                if (sampledTarget == TextureTarget::Texture2DMultisample ||
+                    sampledTarget == TextureTarget::Texture2DMultisampleArray) {
+                    continue;
+                }
+                const auto& levelRange = sampledTexture->GetLevelRange();
+                Bool aliasesWritableImage = false;
+                for (const Uint32 imageBinding : programObj.activeBindings) {
+                    if (imageBinding >= m_maxBindings ||
+                        programObj.bindingKinds[imageBinding] != ProgramFactory::DescriptorBindingKind::StorageImage) {
+                        continue;
+                    }
+                    if (imageBinding >= programObj.samplerUniformLocationByBinding.size()) return false;
+                    const Int baseLocation = programObj.samplerUniformLocationByBinding[imageBinding];
+                    if (baseLocation < 0) return false;
+                    const Uint32 imageCount = BindingDescriptorCount(programObj, imageBinding);
+                    for (Uint32 imageElement = 0; imageElement < imageCount; ++imageElement) {
+                        const Int location = ResolveDescriptorElementLocation(program, baseLocation, imageElement);
+                        if (location < 0) return false;
+                        const Int imageUnit = program.GetUniformSamplerOrImageUnitIndex(static_cast<Uint>(location));
+                        if (imageUnit < 0 || imageUnit >= MG_State::GLState::TextureState::MAX_TEXTURE_IMAGE_UNITS) {
+                            return false;
+                        }
+                        const auto& image = MG_State::pGLContext->GetImageTextureBinding(imageUnit);
+                        // A sampler view exposes all layers of its target; equal texture plus an
+                        // overlapping mip therefore aliases the writable image subresource.
+                        if (image.Texture.get() == sampledTexture &&
+                            SamplerOverlapsWritableImageSubresource(levelRange.x(), levelRange.y(),
+                                                                     image.Level, image.Access)) {
+                            aliasesWritableImage = true;
+                            break;
+                        }
+                    }
+                    if (aliasesWritableImage) break;
+                }
+                if (aliasesWritableImage) {
+                    outBindings.push_back({.samplerBinding = samplerBinding,
+                                           .samplerElement = samplerElement,
+                                           .texture = sampledTexture,
+                                           .sampler = sampledSampler,
+                                           .numericDomain = programObj.samplerNumericDomainByBinding[samplerBinding]});
+                }
+            }
+        }
+        return true;
+    }
+
     Bool UniformManager::ResolveUniformBufferPayload(const MG_State::GLState::ProgramObject& program,
                                                      const ProgramFactory::VkProgramObject& programObj, Uint32 binding,
                                                      Uint32 arrayElement, UboBindResult& out) const {
@@ -1388,7 +1474,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return true;
     }
 
-    Bool UniformManager::CreateDescriptorPool(Uint32 maxSets, VkDescriptorPool& outPool) const {
+    Bool UniformManager::CreateDescriptorPool(Uint32 maxSets, Bool updateAfterBind, VkDescriptorPool& outPool) const {
         outPool = VK_NULL_HANDLE;
         if (m_device == VK_NULL_HANDLE || maxSets == 0 || m_maxBindings == 0) {
             return false;
@@ -1406,7 +1492,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const Uint64 descriptorCount64 =
             static_cast<Uint64>(maxSets) * static_cast<Uint64>(std::min(m_maxBindings, kEstimatedBindingsPerSet));
         if (descriptorCount64 > static_cast<Uint64>(std::numeric_limits<Uint32>::max())) {
-            MGLOG_E("UniformDescriptorBinder::CreateDescriptorPool failed: descriptorCount overflow");
+            MGLOG_E_ONCE("UniformDescriptorBinder::CreateDescriptorPool failed: descriptorCount overflow");
             return false;
         }
 
@@ -1431,38 +1517,43 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // (OnDescriptorSetLayoutDestroyed) so program churn recycles pool capacity.
         // The cost is on set allocation only, which happens when a layout's per-frame
         // cache grows - never on the per-draw reuse path.
-        poolInfo.flags = VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT;
+        poolInfo.flags = VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT |
+                         (updateAfterBind ? VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT : 0);
         poolInfo.maxSets = maxSets;
         poolInfo.poolSizeCount = static_cast<Uint32>(std::size(poolSizes));
         poolInfo.pPoolSizes = poolSizes;
 
         const VkResult result = vkCreateDescriptorPool(m_device, &poolInfo, nullptr, &outPool);
         if (result != VK_SUCCESS) {
-            MGLOG_E("UniformDescriptorBinder::CreateDescriptorPool failed: vkCreateDescriptorPool returned %d",
+            MGLOG_E_ONCE("UniformDescriptorBinder::CreateDescriptorPool failed: vkCreateDescriptorPool returned %d",
                     result);
             return false;
         }
         return true;
     }
 
-    Bool UniformManager::GrowFrameDescriptorPool(FrameResources& frame, Uint32 frameIndex) {
+    Bool UniformManager::GrowFrameDescriptorPool(FrameResources& frame, Uint32 frameIndex, Bool updateAfterBind) {
         if (frame.descriptorPools.empty()) {
             return false;
         }
 
-        const auto& currentBucket = frame.descriptorPools[frame.activeDescriptorPoolIndex];
-        const Uint32 currentMaxSets = std::max<Uint32>(1, currentBucket.maxSets);
+        const auto matchingBucket = std::find_if(
+            frame.descriptorPools.begin(), frame.descriptorPools.end(),
+            [updateAfterBind](const DescriptorPoolBucket& candidate) { return candidate.updateAfterBind == updateAfterBind; });
+        const Uint32 currentMaxSets = matchingBucket != frame.descriptorPools.end()
+                                          ? std::max<Uint32>(1, matchingBucket->maxSets)
+                                          : m_setsPerFrame;
         const Uint32 grownMaxSets = currentMaxSets <= (std::numeric_limits<Uint32>::max() / 2) ? (currentMaxSets * 2)
                                                                                                  : currentMaxSets;
 
         VkDescriptorPool grownPool = VK_NULL_HANDLE;
-        if (!CreateDescriptorPool(grownMaxSets, grownPool)) {
-            MGLOG_E("UniformDescriptorBinder::GrowFrameDescriptorPool failed: cannot create grown pool (%u -> %u sets)",
+        if (!CreateDescriptorPool(grownMaxSets, updateAfterBind, grownPool)) {
+            MGLOG_E_ONCE("UniformDescriptorBinder::GrowFrameDescriptorPool failed: cannot create grown pool (%u -> %u sets)",
                     currentMaxSets, grownMaxSets);
             return false;
         }
 
-        frame.descriptorPools.push_back({grownPool, grownMaxSets, 0});
+        frame.descriptorPools.push_back({grownPool, grownMaxSets, 0, updateAfterBind});
         frame.activeDescriptorPoolIndex = static_cast<Uint32>(frame.descriptorPools.size() - 1);
         MGLOG_D(
             "UniformDescriptorBinder: frame %u descriptor pool exhausted, grew pool (%u -> %u sets), poolCount=%zu",
@@ -1472,14 +1563,16 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
     VkResult UniformManager::AllocateDescriptorSetsFromActivePool(Uint32 frameIndex, const ProgramFactory::VkProgramObject& programObj, VkDescriptorSet& outDescriptorSet) {
         auto& frame = m_frames[frameIndex];
-        if (frame.activeDescriptorPoolIndex >= frame.descriptorPools.size()) {
-            frame.activeDescriptorPoolIndex = 0;
-        }
-        if (frame.descriptorPools[frame.activeDescriptorPoolIndex].allocatedSets >=
-            frame.descriptorPools[frame.activeDescriptorPoolIndex].maxSets) {
+        const Bool updateAfterBind = programObj.usesUpdateAfterBind;
+        if (frame.activeDescriptorPoolIndex >= frame.descriptorPools.size() ||
+            frame.descriptorPools[frame.activeDescriptorPoolIndex].updateAfterBind != updateAfterBind ||
+            frame.descriptorPools[frame.activeDescriptorPoolIndex].allocatedSets >=
+                frame.descriptorPools[frame.activeDescriptorPoolIndex].maxSets) {
             const auto availableBucket = std::find_if(
                 frame.descriptorPools.begin(), frame.descriptorPools.end(),
-                [](const DescriptorPoolBucket& candidate) { return candidate.allocatedSets < candidate.maxSets; });
+                [updateAfterBind](const DescriptorPoolBucket& candidate) {
+                    return candidate.updateAfterBind == updateAfterBind && candidate.allocatedSets < candidate.maxSets;
+                });
             if (availableBucket == frame.descriptorPools.end()) {
                 outDescriptorSet = VK_NULL_HANDLE;
                 return VK_ERROR_OUT_OF_POOL_MEMORY;
@@ -1515,8 +1608,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         } else {
             VkResult allocResult = AllocateDescriptorSetsFromActivePool(frameIndex, programObj, outDescriptorSet);
             if (allocResult == VK_ERROR_OUT_OF_POOL_MEMORY || allocResult == VK_ERROR_FRAGMENTED_POOL) {
-                if (!GrowFrameDescriptorPool(frame, frameIndex)) {
-                    MGLOG_E("UniformDescriptorBinder::AcquireDescriptorSet failed: descriptor pool growth failed");
+                if (!GrowFrameDescriptorPool(frame, frameIndex, programObj.usesUpdateAfterBind)) {
+                    MGLOG_E_ONCE("UniformDescriptorBinder::AcquireDescriptorSet failed: descriptor pool growth failed");
                     return allocResult;
                 }
                 allocResult = AllocateDescriptorSetsFromActivePool(frameIndex, programObj, outDescriptorSet);
@@ -1633,7 +1726,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                                              Uint32 frameIndex,
                                                              VkPipelineBindPoint bindPoint,
                                                              const SamplerBindingOverride* samplerBindingOverride,
-                                                             Bool samplerDescriptorsUnchangedHint) {
+                                                             Bool samplerDescriptorsUnchangedHint,
+                                                             const Vector<SamplerBindingOverride>* samplerBindingOverrides) {
         // This program has a descriptor MobileGL could not resolve (see
         // VkProgramObject::declinedDescriptors). Refusing here is the whole of the decline: the
         // binding is still declared in the layout, so the pipeline is consistent with the shader
@@ -1647,7 +1741,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
         auto& frame = m_frames[frameIndex];
         if (frame.descriptorPools.empty()) {
-            MGLOG_E("UniformDescriptorBinder::BindProgramUniformBuffers failed: frame descriptor pools are invalid");
+            MGLOG_E_ONCE("UniformDescriptorBinder::BindProgramUniformBuffers failed: frame descriptor pools are invalid");
             return false;
         }
         if (frame.activeDescriptorPoolIndex >= frame.descriptorPools.size()) {
@@ -1660,7 +1754,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // sampler binding, and an unchanged (buffer, range) for the single
         // dynamic UBO covers the rest - except the dynamic offset, which rebinding
         // the SAME set delivers without any descriptor write.
-        const Bool cacheable = (samplerBindingOverride == nullptr);
+        const Bool cacheable = samplerBindingOverride == nullptr &&
+                               (samplerBindingOverrides == nullptr || samplerBindingOverrides->empty());
         if (cacheable && samplerDescriptorsUnchangedHint && m_fastRebindMemo.valid &&
             m_fastRebindMemo.frameIndex == frameIndex &&
             m_fastRebindMemo.programLifetimeId == program.GetLifetimeId() &&
@@ -1784,7 +1879,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 VkBufferView bufferView = VK_NULL_HANDLE;
                 if (!ResolveTexelBufferDescriptor(program, programObj, binding, frameIndex, bufferView) ||
                     bufferView == VK_NULL_HANDLE) {
-                    MGLOG_E(
+                    MGLOG_E_ONCE(
                         "UniformDescriptorBinder::BindProgramUniformBuffers failed: texture buffer binding %u has no valid descriptor",
                         binding);
                     return false;
@@ -1803,7 +1898,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 VkBufferView bufferView = VK_NULL_HANDLE;
                 if (!ResolveStorageTexelBufferDescriptor(program, programObj, binding, frameIndex, bufferView) ||
                     bufferView == VK_NULL_HANDLE) {
-                    MGLOG_E("UniformDescriptorBinder::BindProgramUniformBuffers failed: image buffer binding %u "
+                    MGLOG_E_ONCE("UniformDescriptorBinder::BindProgramUniformBuffers failed: image buffer binding %u "
                             "has no valid descriptor",
                             binding);
                     return false;
@@ -1823,7 +1918,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 for (Uint32 element = 0; element < descriptorCount; ++element) {
                     VkDescriptorBufferInfo bufferInfo{};
                     if (!ResolveStorageBufferDescriptor(program, programObj, binding, element, bufferInfo)) {
-                        MGLOG_E(
+                        MGLOG_E_ONCE(
                             "UniformDescriptorBinder::BindProgramUniformBuffers failed: storage buffer binding %u "
                             "element %u has no valid descriptor",
                             binding, element);
@@ -1850,7 +1945,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     VkDescriptorImageInfo imageInfo{};
                     if (!ResolveStorageImageDescriptor(commandBuffer, program, programObj, binding, element,
                                                        imageInfo)) {
-                        MGLOG_E(
+                        MGLOG_E_ONCE(
                             "UniformDescriptorBinder::BindProgramUniformBuffers failed: storage image binding %u "
                             "element %u has no valid descriptor",
                             binding, element);
@@ -1884,22 +1979,32 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 const SizeT firstImageInfoIndex = imageInfos.size();
                 for (Uint32 element = 0; element < descriptorCount; ++element) {
                     VkDescriptorImageInfo imageInfo{};
-                    Bool hasImage = false;
-                    if (overrideThisBinding && element == 0) {
-                        hasImage = ResolveSamplerDescriptorOverride(*samplerBindingOverride, imageInfo);
-                    } else {
-                        hasImage = ResolveSamplerDescriptor(commandBuffer, program, programObj, binding, element,
-                                                            imageInfo, samplerDescriptorsUnchangedHint);
+                    const SamplerBindingOverride* overrideForElement =
+                        overrideThisBinding && element == 0 ? samplerBindingOverride : nullptr;
+                    if (overrideForElement == nullptr && samplerBindingOverrides != nullptr) {
+                        const auto overrideIt = std::find_if(
+                            samplerBindingOverrides->begin(), samplerBindingOverrides->end(),
+                            [binding, element](const SamplerBindingOverride& candidate) {
+                                return candidate.binding == binding && candidate.element == element;
+                            });
+                        if (overrideIt != samplerBindingOverrides->end()) {
+                            overrideForElement = &*overrideIt;
+                        }
                     }
+                    const Bool hasImage = overrideForElement != nullptr
+                                              ? ResolveSamplerDescriptorOverride(*overrideForElement, imageInfo)
+                                              : ResolveSamplerDescriptor(commandBuffer, program, programObj, binding,
+                                                                         element, imageInfo,
+                                                                         samplerDescriptorsUnchangedHint);
                     if (!hasImage) {
-                        MGLOG_E(
+                        MGLOG_E_ONCE(
                             "UniformDescriptorBinder::BindProgramUniformBuffers failed: sampler binding %u element %u "
                             "has no valid texture descriptor",
                             binding, element);
                         return false;
                     }
                     if (imageInfo.sampler == VK_NULL_HANDLE || imageInfo.imageView == VK_NULL_HANDLE) {
-                        MGLOG_E(
+                        MGLOG_E_ONCE(
                             "UniformDescriptorBinder::BindProgramUniformBuffers failed: sampler binding %u element %u "
                             "has null sampler or imageView",
                             binding, element);
@@ -1973,7 +2078,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         } else {
             VkResult allocResult = AcquireDescriptorSet(frameIndex, programObj, descriptorSet);
             if (allocResult != VK_SUCCESS || descriptorSet == VK_NULL_HANDLE) {
-                MGLOG_E("UniformDescriptorBinder::BindProgramUniformBuffers failed: descriptor set acquire returned %d",
+                MGLOG_E_ONCE("UniformDescriptorBinder::BindProgramUniformBuffers failed: descriptor set acquire returned %d",
                         allocResult);
                 return false;
             }

MobileGL/MG_Backend/DirectVulkan/Renderer/UniformManager.h

@@ -26,9 +26,20 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     public:
         struct SamplerBindingOverride {
             Uint32 binding = 0;
+            Uint32 element = 0;
             MG_State::GLState::ITextureObject* texture = nullptr;
             const MG_State::GLState::SamplerObject* sampler = nullptr;
             VkImageView imageView = VK_NULL_HANDLE;
+            VkImageLayout imageLayout = VK_IMAGE_LAYOUT_UNDEFINED;
+            Bool forceNearestFiltering = false;
+        };
+
+        struct SamplerImageFeedbackBinding {
+            Uint32 samplerBinding = 0;
+            Uint32 samplerElement = 0;
+            MG_State::GLState::ITextureObject* texture = nullptr;
+            const MG_State::GLState::SamplerObject* sampler = nullptr;
+            SamplerNumericDomain numericDomain = SamplerNumericDomain::Unknown;
         };
 
         Bool Initialize(VkDevice device, VkBufferManager* bufferManager,
@@ -79,6 +90,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Bool CollectStorageImageTextures(const MG_State::GLState::ProgramObject& program,
                                          const ProgramFactory::VkProgramObject& programObj,
                                          Vector<MG_State::GLState::ITextureObject*>& outTextures) const;
+        Bool CollectSamplerImageFeedback(
+            const MG_State::GLState::ProgramObject& program,
+            const ProgramFactory::VkProgramObject& programObj,
+            Vector<SamplerImageFeedbackBinding>& outBindings) const;
+        static Bool SamplerOverlapsWritableImageSubresource(Int samplerBaseLevel, Int samplerMaxLevel,
+                                                             GLint imageLevel, GLenum imageAccess);
         // samplerDescriptorsUnchangedHint: the caller (SetupDraw fast path) proved that
         // every input of every combined-image-sampler resolution is unchanged since the
         // previous draw's resolve - same (texture, sampler) per binding, texture params
@@ -91,7 +108,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                        Uint32 frameIndex,
                                        VkPipelineBindPoint bindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS,
                                        const SamplerBindingOverride* samplerBindingOverride = nullptr,
-                                       Bool samplerDescriptorsUnchangedHint = false);
+                                       Bool samplerDescriptorsUnchangedHint = false,
+                                       const Vector<SamplerBindingOverride>* samplerBindingOverrides = nullptr);
 
         // Pure format-policy helper kept public for host regression tests. Formatted storage
         // images use their shader qualifier; transformed float images use glBindImageTexture's
@@ -114,6 +132,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             VkDescriptorPool handle = VK_NULL_HANDLE;
             Uint32 maxSets = 0;
             Uint32 allocatedSets = 0;
+            Bool updateAfterBind = false;
         };
 
         // A cached descriptor set together with the pool it was allocated from, so a
@@ -223,8 +242,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         void BindDescriptorSetDeduped(VkCommandBuffer commandBuffer, VkPipelineBindPoint bindPoint,
                                       VkPipelineLayout pipelineLayout, VkDescriptorSet descriptorSet,
                                       const Vector<Uint32>& dynamicOffsets);
-        Bool CreateDescriptorPool(Uint32 maxSets, VkDescriptorPool& outPool) const;
-        Bool GrowFrameDescriptorPool(FrameResources& frame, Uint32 frameIndex);
+        Bool CreateDescriptorPool(Uint32 maxSets, Bool updateAfterBind, VkDescriptorPool& outPool) const;
+        Bool GrowFrameDescriptorPool(FrameResources& frame, Uint32 frameIndex, Bool updateAfterBind);
         VkResult AllocateDescriptorSetsFromActivePool(
             Uint32 frameIndex, const ProgramFactory::VkProgramObject& programObj, VkDescriptorSet& outDescriptorSet);
         VkResult AcquireDescriptorSet(Uint32 frameIndex,
@@ -341,8 +360,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // lifetime id, so a freed-and-reallocated sampler or texture at the same heap address
         // always gets a fresh id and misses (a raw pointer would false-hit that ABA) - so a
         // stale guess can only miss and fall through to the hash, never resolve wrong. Still
-        // reset each frame alongside the descriptor-set cache. Indexed by binding.
+        // reset each frame alongside the descriptor-set cache. Indexed by binding, but the
+        // whole-descriptor entry is additionally keyed by program lifetime: Vulkan binding
+        // numbers are layout-local and unrelated programs routinely reuse binding 0/1.
         struct SamplerResolveMemo {
+            Uint64 infoProgramLifetimeId = 0;
             Uint64 samplerLifetimeId = 0;
             Uint64 textureLifetimeId = 0;
             VkSampler sampler = VK_NULL_HANDLE;

MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.cpp

@@ -8,6 +8,7 @@
 
 #include "VertexInputStateFactory.h"
 #include "MG_Util/Converters/MGToStr/DataTypeConverter.h"
+#include <MG_Backend/BackendObjects.h>
 #include <utility>
 
 namespace MobileGL::MG_Backend::DirectVulkan {
@@ -107,10 +108,36 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 continue;
             }
 
-            const VkFormat sourceVkFormat =
+            VkFormat sourceVkFormat =
                 ToVkVertexFormat(attr.Type, attr.Size, attr.Normalized, attr.IsInteger, attr.IsBgra, attr.IsLong);
+            VertexStreamConversion conversion = VertexStreamConversion::None;
+            // Gated on the SAME flag ToVkVertexFormat gates its 64-bit path on, and that is
+            // load-bearing rather than belt-and-braces: the narrowing is only correct because the
+            // shader's `dvec` input is a `vec` by the time the pipeline is built, and what
+            // guarantees that is the flag being clear. It is clear on every backend today, and a
+            // program with a 64-bit float vertex input is demoted WHOLE for the same reason even
+            // where the device has native fp64 (ProgramSpirvTask::GenerateSpirv). With the flag
+            // set, a dvec3/dvec4 would be declined by ToVkVertexFormat AND left 64-bit in the
+            // module, so a float32 stream would be fed to a Float64 input.
+            const Bool narrowFloat64Arrays =
+                MG_Backend::pActiveBackendObject == nullptr ||
+                !MG_Backend::pActiveBackendObject->GetDynamicParameters().SupportsFloat64VertexAttributes;
+            if (sourceVkFormat == VK_FORMAT_UNDEFINED && attr.Type == DataType::Float64 && narrowFloat64Arrays) {
+                // No native 64-bit fetch here (see ToVkVertexFormat's Float64 case), but the
+                // source bytes are ordinary IEEE-754 doubles and DemoteFloat64Pass has already
+                // narrowed every dvec input to a vec, so the array is narrowed to match rather
+                // than dropped. Mirrors what DirectGLES does for the same state.
+                const VkFormat narrowedFormat = ToFloat32VertexFormat(attr.Size);
+                if (narrowedFormat != VK_FORMAT_UNDEFINED && SupportsVertexBufferFormat(narrowedFormat)) {
+                    sourceVkFormat = narrowedFormat;
+                    conversion = VertexStreamConversion::Float64ToFloat32;
+                    MGLOG_W_ONCE("Vertex attribute location=%u is a 64-bit (GL_DOUBLE) array; fetching it at "
+                            "float32 precision through format=%d (size=%d long=%s)",
+                            location, static_cast<Int>(narrowedFormat), attr.Size, attr.IsLong ? "true" : "false");
+                }
+            }
             if (sourceVkFormat == VK_FORMAT_UNDEFINED) {
-                MGLOG_E("Unsupported vertex attribute layout (location=%u, type=%s, size=%d): the array is "
+                MGLOG_E_ONCE("Unsupported vertex attribute layout (location=%u, type=%s, size=%d): the array is "
                         "enabled but cannot be mapped to a VkFormat",
                         location, MG_Util::ConvertDataTypeToString(attr.Type).c_str(), attr.Size);
                 unsupportedAttribMask |= (1u << location);
@@ -118,14 +145,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             }
 
             VkFormat vkFormat = sourceVkFormat;
-            VertexStreamConversion conversion = VertexStreamConversion::None;
-            if (!SupportsVertexBufferFormat(vkFormat)) {
+            if (conversion == VertexStreamConversion::None && !SupportsVertexBufferFormat(vkFormat)) {
                 if (IsScaledIntegerVertexFormat(vkFormat)) {
                     const VkFormat fallbackFormat = ToFloat32VertexFormat(attr.Size);
                     if (fallbackFormat != VK_FORMAT_UNDEFINED && SupportsVertexBufferFormat(fallbackFormat)) {
                         vkFormat = fallbackFormat;
                         conversion = VertexStreamConversion::ScaledIntegerToFloat32;
-                        MGLOG_W("Vertex attribute location=%u format=%d lacks "
+                        MGLOG_W_ONCE("Vertex attribute location=%u format=%d lacks "
                                 "VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT; using float32 stream format=%d "
                                 "(type=%s size=%d normalized=%s integer=%s)",
                                 location, static_cast<Int>(sourceVkFormat), static_cast<Int>(vkFormat),
@@ -135,7 +161,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 }
 
                 if (conversion == VertexStreamConversion::None) {
-                    MGLOG_E("Unsupported Vulkan vertex format (location=%u, format=%d, type=%s, size=%d): "
+                    MGLOG_E_ONCE("Unsupported Vulkan vertex format (location=%u, format=%d, type=%s, size=%d): "
                             "VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT is unavailable and no semantic fallback exists",
                             location, static_cast<Int>(sourceVkFormat),
                             MG_Util::ConvertDataTypeToString(attr.Type).c_str(), attr.Size);
@@ -146,7 +172,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
             const SizeT attribByteSize = GetAttributeByteSize(attr.Type, attr.Size, attr.IsBgra);
             if (attribByteSize == 0) {
-                MGLOG_E("Vertex attribute with unknown component size (location=%u, type=%s): the array is "
+                MGLOG_E_ONCE("Vertex attribute with unknown component size (location=%u, type=%s): the array is "
                         "enabled but cannot be sized",
                         location, MG_Util::ConvertDataTypeToString(attr.Type).c_str());
                 unsupportedAttribMask |= (1u << location);
@@ -175,7 +201,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 // unless VK_EXT_legacy_vertex_attributes is available, so deinterleave this one
                 // attribute into a tightly packed transient stream without changing its format.
                 conversion = VertexStreamConversion::Repack;
-                MGLOG_W("Vertex attribute location=%u uses Vulkan-incompatible alignment "
+                MGLOG_W_ONCE("Vertex attribute location=%u uses Vulkan-incompatible alignment "
                         "(offset=%zu stride=%u required=%zu); using a tightly packed stream",
                         location, attr.Offset, sourceStride, requiredAlignment);
             }
@@ -188,7 +214,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             if (sourceStride != 0) {
                 if (conversion == VertexStreamConversion::Repack) {
                     stride = static_cast<Uint32>(attribByteSize);
-                } else if (conversion == VertexStreamConversion::ScaledIntegerToFloat32) {
+                } else if (conversion == VertexStreamConversion::ScaledIntegerToFloat32 ||
+                           conversion == VertexStreamConversion::Float64ToFloat32) {
                     stride = static_cast<Uint32>(attr.Size * static_cast<Int>(sizeof(Float)));
                 }
             }
@@ -287,8 +314,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             if (m_frameBoundaryCounter - it->second->lastUsedFrameBoundary > kRetireAgeBoundaries) {
                 it = m_cache.erase(it);
                 // Invalidate every VAO's state-pointer memo: the erased node's
-                // address may be reused by a future insert.
-                ++m_evictionEpoch;
+                // address may be reused by a future insert. Advance through the
+                // process-wide source so the value stays unique across factory
+                // instances (see the member comment).
+                m_evictionEpoch = ++s_evictionEpochSource;
             } else {
                 ++it;
             }
@@ -328,6 +357,20 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // for every R64 float format, so a native 64-bit vertex fetch is simply unavailable there
             // while shaderFloat64 is not. Both halves key off nothing but the attribute being long,
             // so they always agree without extra plumbing.
+            //
+            // ... as long as the shader half still runs. It does not when the backend has declared
+            // no 64-bit vertex attribute support: DemoteFloat64Pass has already narrowed every
+            // `dvec` input to a `vec` by then, so PackDoubleVertexInputsPass finds nothing to pack
+            // and a UINT-formatted attribute would be fed to a float input - garbage with no
+            // diagnostic anywhere. Declining here hands the attribute to the caller's
+            // Float64ToFloat32 fallback instead, which narrows the source doubles to match the
+            // demoted `vec` input - the same thing DirectGLES does for the same state. The
+            // frontend RECORDS the format either way, so this gate is the only thing standing
+            // between a legal glVertexAttribLFormat and a mismatched pipeline.
+            if (MG_Backend::pActiveBackendObject == nullptr ||
+                !MG_Backend::pActiveBackendObject->GetDynamicParameters().SupportsFloat64VertexAttributes) {
+                return VK_FORMAT_UNDEFINED;
+            }
             if (!isLong || isInteger || normalized) return VK_FORMAT_UNDEFINED;
             switch (size) {
             case 1: return VK_FORMAT_R32G32_UINT;

MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.h

@@ -23,6 +23,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             None = 0,
             Repack,
             ScaledIntegerToFloat32,
+            // GL_DOUBLE source data narrowed to a tightly packed float32 stream: the fetch half
+            // of the fp64 demotion the shader side already does unconditionally.
+            Float64ToFloat32,
         };
 
         struct BackendVertexInputState {
@@ -125,7 +128,17 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // construction); a memo is honored only while its recorded epoch
         // matches, so an evicted entry can never be dereferenced through a
         // stale memo.
-        Uint64 m_evictionEpoch = 1;
+        //
+        // Drawn from a process-wide source, never a per-instance counter: the VAO
+        // memos outlive this factory (they live on pGLContext's VAOs, the renderer
+        // is destroyed and recreated on EGL surface release/re-create), so a fresh
+        // factory restarting at a dead factory's epoch value would honor its
+        // dangling entry pointers. The constructor takes a value strictly greater
+        // than anything a predecessor ever stamped, so a dead factory's memo can
+        // never compare equal here - the same never-reused idiom as the lifetime ids.
+        // Single-threaded like the rest of the factory (renderer-thread only).
+        static inline Uint64 s_evictionEpochSource = 0;
+        Uint64 m_evictionEpoch = ++s_evictionEpochSource;
         static inline XXH64_state_t* m_hashState = XXH64_createState();
     };
 } // namespace MobileGL::MG_Backend::DirectVulkan

MobileGL/MG_Backend/DirectVulkan/Renderer/VkBufferManager.cpp

@@ -302,7 +302,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             .requiredFlags = requiredFlags,
         });
         if (!created || resource.buffer.Map() == nullptr) {
-            MGLOG_E("VkBufferManager::CreateResidentStorage failed (size=%llu)",
+            MGLOG_E_ONCE("VkBufferManager::CreateResidentStorage failed (size=%llu)",
                     static_cast<unsigned long long>(size));
             resource.buffer.Destroy();
             resource.storageSize = 0;
@@ -324,7 +324,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             return false;
         }
         if (!resource.buffer.Upload(bufferObject.MappedData(), size, 0)) {
-            MGLOG_E("VkBufferManager::SwapStorageAndUploadAll: upload failed");
+            MGLOG_E_ONCE("VkBufferManager::SwapStorageAndUploadAll: upload failed");
             resource.pendingFullUpload = true;
             return false;
         }
@@ -409,7 +409,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
 
         if (!resource->buffer.Upload(bufferObject.MappedData(), size, 0)) {
-            MGLOG_E("VkBufferManager::OnRespecify: in-place upload failed");
+            MGLOG_E_ONCE("VkBufferManager::OnRespecify: in-place upload failed");
             resource->pendingFullUpload = true;
         }
     }
@@ -434,7 +434,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         if (!IsResourceBusy(*resource)) {
             if (!resource->buffer.Upload(bufferObject.MappedData() + offset,
                                          static_cast<VkDeviceSize>(size), static_cast<VkDeviceSize>(offset))) {
-                MGLOG_E("VkBufferManager::OnSubData: host upload failed");
+                MGLOG_E_ONCE("VkBufferManager::OnSubData: host upload failed");
                 resource->pendingFullUpload = true;
             }
             return;
@@ -471,7 +471,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         if ((appAccess & BufferMappingAccessBit::Unsynchronized) || !IsResourceBusy(*resource)) {
             if (!resource->buffer.Upload(bufferObject.MappedData() + offset,
                                          static_cast<VkDeviceSize>(size), static_cast<VkDeviceSize>(offset))) {
-                MGLOG_E("VkBufferManager::OnFlushMappedRange: host upload failed");
+                MGLOG_E_ONCE("VkBufferManager::OnFlushMappedRange: host upload failed");
                 resource->pendingFullUpload = true;
             }
             return;
@@ -563,7 +563,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         const VkDeviceSize size = static_cast<VkDeviceSize>(bufferObject->GetSize());
         if (size == 0) {
-            MGLOG_E("VkBufferManager::AcquireResidentSlice failed: buffer size is zero");
+            MGLOG_E_ONCE("VkBufferManager::AcquireResidentSlice failed: buffer size is zero");
             return false;
         }
 
@@ -585,7 +585,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 return false;
             }
             if (!resource->buffer.Upload(bufferObject->MappedData(), size, 0)) {
-                MGLOG_E("VkBufferManager::AcquireResidentSlice failed: initial upload failed");
+                MGLOG_E_ONCE("VkBufferManager::AcquireResidentSlice failed: initial upload failed");
                 resource->buffer.Destroy();
                 resource->storageSize = 0;
                 resource->usageFlags = 0;
@@ -620,7 +620,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         const VkDeviceSize size = static_cast<VkDeviceSize>(bufferObject->GetSize());
         if (size == 0) {
-            MGLOG_E("VkBufferManager::AcquireStreamedSlice failed: buffer size is zero");
+            MGLOG_E_ONCE("VkBufferManager::AcquireStreamedSlice failed: buffer size is zero");
             return false;
         }
 

MobileGL/MG_Backend/DirectVulkan/Renderer/VkBufferObject.cpp

@@ -76,7 +76,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const VkResult result =
             vmaCreateBuffer(m_allocator, &bufferInfo, &allocationInfo, &m_buffer, &m_allocation, nullptr);
         if (result != VK_SUCCESS) {
-            MGLOG_E("VkBufferObject::Create failed: vmaCreateBuffer returned %d", result);
+            MGLOG_E_ONCE("VkBufferObject::Create failed: vmaCreateBuffer returned %d", result);
             m_allocator = nullptr;
             m_buffer = VK_NULL_HANDLE;
             m_allocation = nullptr;
@@ -108,7 +108,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         const VkResult mapResult = vmaMapMemory(m_allocator, m_allocation, &m_mappedData);
         if (mapResult != VK_SUCCESS || m_mappedData == nullptr) {
-            MGLOG_E("VkBufferObject::Map failed: vmaMapMemory returned %d", mapResult);
+            MGLOG_E_ONCE("VkBufferObject::Map failed: vmaMapMemory returned %d", mapResult);
             m_mappedData = nullptr;
             return nullptr;
         }
@@ -138,14 +138,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const Bool wasMapped = IsMapped();
         void* mapped = wasMapped ? m_mappedData : Map();
         if (mapped == nullptr) {
-            MGLOG_E("VkBufferObject::Upload failed: unable to map buffer");
+            MGLOG_E_ONCE("VkBufferObject::Upload failed: unable to map buffer");
             return false;
         }
 
         Memcpy(static_cast<Uint8*>(mapped) + offset, data, static_cast<SizeT>(size));
         const VkResult flushResult = vmaFlushAllocation(m_allocator, m_allocation, offset, size);
         if (flushResult != VK_SUCCESS) {
-            MGLOG_E("VkBufferObject::Upload failed: vmaFlushAllocation returned %d", flushResult);
+            MGLOG_E_ONCE("VkBufferObject::Upload failed: vmaFlushAllocation returned %d", flushResult);
             if (!wasMapped) {
                 Unmap();
             }
@@ -170,7 +170,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         const VkResult result = vmaInvalidateAllocation(m_allocator, m_allocation, offset, resolvedSize);
         if (result != VK_SUCCESS) {
-            MGLOG_E("VkBufferObject::Invalidate failed: vmaInvalidateAllocation returned %d", result);
+            MGLOG_E_ONCE("VkBufferObject::Invalidate failed: vmaInvalidateAllocation returned %d", result);
             return false;
         }
         return true;

MobileGL/MG_Backend/DirectVulkan/Renderer/VkClearManager.cpp

@@ -166,7 +166,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     void VkClearManager::MergeClearPayload(ClearAttachmentPayload& dst, const ClearAttachmentPayload& src) {
         dst.mask |= src.mask;
         if ((src.mask & GL_COLOR_BUFFER_BIT) != 0) {
+            // The whole colour story travels together (same rule as
+            // VkRenderPassManager::QueueRenderbufferClear): a glClearBufferiv/uiv
+            // payload carries its value in colorInt/colorUint and its branch selector
+            // in colorEncoding - dropping them here would leave the pending clear
+            // reading as an all-zero float one.
             dst.color = src.color;
+            dst.colorEncoding = src.colorEncoding;
+            dst.colorInt = src.colorInt;
+            dst.colorUint = src.colorUint;
         }
         if ((src.mask & GL_DEPTH_BUFFER_BIT) != 0) {
             dst.depth = src.depth;

MobileGL/MG_Backend/DirectVulkan/Renderer/VkRenderPassManager.cpp

@@ -123,7 +123,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
 
         if (!attachment.IsComplete()) {
-            MGLOG_W("GetOrCreateRenderPass: draw buffer slot %u (%s) on FBO %u has an incomplete texture attachment; using VK_ATTACHMENT_UNUSED",
+            MGLOG_W_ONCE("GetOrCreateRenderPass: draw buffer slot %u (%s) on FBO %u has an incomplete texture attachment; using VK_ATTACHMENT_UNUSED",
                     drawBufferIndex,
                     MG_Util::ConvertFramebufferAttachmentTypeToString(attachmentType).c_str(),
                     fbo.GetExternalIndex());
@@ -132,7 +132,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         auto* texture = attachment.GetTexture().get();
         if (texture == nullptr) {
-            MGLOG_W("GetOrCreateRenderPass: draw buffer slot %u (%s) on FBO %u resolved to a null texture; using VK_ATTACHMENT_UNUSED",
+            MGLOG_W_ONCE("GetOrCreateRenderPass: draw buffer slot %u (%s) on FBO %u resolved to a null texture; using VK_ATTACHMENT_UNUSED",
                     drawBufferIndex,
                     MG_Util::ConvertFramebufferAttachmentTypeToString(attachmentType).c_str(),
                     fbo.GetExternalIndex());
@@ -311,7 +311,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         VkSampleCountFlagBits sampleCount = VK_SAMPLE_COUNT_1_BIT;
         if (!TryResolveSampleCountFlagBits(renderbuffer->GetSamples(), sampleCount)) {
-            MGLOG_E("GetOrCreateRenderbufferResource: unsupported renderbuffer sample count %d for renderbuffer %u",
+            MGLOG_E_ONCE("GetOrCreateRenderbufferResource: unsupported renderbuffer sample count %d for renderbuffer %u",
                     renderbuffer->GetSamples(),
                     renderbuffer->GetExternalIndex());
             return nullptr;
@@ -457,7 +457,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             m_physicalDevice, format, imageInfo.imageType, imageInfo.tiling, imageInfo.usage, imageInfo.flags,
             &imageFormatProperties);
         if (imageFormatResult != VK_SUCCESS || (imageFormatProperties.sampleCounts & sampleCount) == 0) {
-            MGLOG_E("GetOrCreateRenderbufferResource: unsupported renderbuffer format=%d samples=%d for renderbuffer %u",
+            MGLOG_E_ONCE("GetOrCreateRenderbufferResource: unsupported renderbuffer format=%d samples=%d for renderbuffer %u",
                     static_cast<Int>(format),
                     static_cast<Int>(sampleCount),
                     renderbuffer->GetExternalIndex());
@@ -831,6 +831,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // recreated since (texture + renderbuffer image epochs), and no pending clear (which alters
         // load ops). Any of these differing forces the full recompute below. Portable to VK 1.1.
         if (activeRenderPass != nullptr && m_rpFastValid && m_rpFastFbo == &fbo &&
+            m_rpFastFboLifetimeId == fbo.GetLifetimeId() &&
             m_rpFastFboVersion == fbo.GetObjectVersion() && m_rpFastSwapchainIndex == swapchainImageIndex &&
             m_rpFastTexEpoch == m_textureManager.GetTextureImageEpoch() &&
             m_rpFastRbEpoch == m_renderbufferImageEpoch &&
@@ -855,6 +856,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // epochs AFTER ComputeHash: its attachment SyncTexture can create an image (bump the epoch).
             m_rpFastValid = true;
             m_rpFastFbo = &fbo;
+            m_rpFastFboLifetimeId = fbo.GetLifetimeId();
             m_rpFastFboVersion = fbo.GetObjectVersion();
             m_rpFastSwapchainIndex = swapchainImageIndex;
             m_rpFastTexEpoch = m_textureManager.GetTextureImageEpoch();
@@ -929,7 +931,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     const auto& renderbuffer = rbAtt.GetRenderbuffer();
                     auto* rbResource = GetOrCreateRenderbufferResource(renderbuffer);
                     if (rbResource == nullptr || (rbResource->aspect & VK_IMAGE_ASPECT_COLOR_BIT) == 0) {
-                        MGLOG_E("GetOrCreateRenderPass: draw buffer slot %u on FBO %u has an unsupported color "
+                        MGLOG_E_ONCE("GetOrCreateRenderPass: draw buffer slot %u on FBO %u has an unsupported color "
                                 "renderbuffer %u; using VK_ATTACHMENT_UNUSED",
                                 i, fbo.GetExternalIndex(), renderbuffer->GetExternalIndex());
                         continue;
@@ -1105,7 +1107,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     adoptRenderPassSampleCount(attachmentSampleCount, "color", texture->GetExternalIndex());
 
                     if (!hasClear && trackedColorLayout == VK_IMAGE_LAYOUT_UNDEFINED) {
-                        MGLOG_W("GetOrCreateRenderPass: color attachment textureId=%d starts with undefined layout and no clear; "
+                        MGLOG_W_ONCE("GetOrCreateRenderPass: color attachment textureId=%d starts with undefined layout and no clear; "
                                 "using LOAD_OP_DONT_CARE",
                                 texture->GetExternalIndex());
                         desc.loadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
@@ -1161,7 +1163,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             isUsableDepthStencilAttachment(depthAtt) && isUsableDepthStencilAttachment(stencilAtt) &&
             !sameDepthStencilAttachmentObject(depthAtt, stencilAtt);
         if (hasDistinctDepthAndStencilAttachments) {
-            MGLOG_E("GetOrCreateRenderPass: separate depth/stencil attachments are not supported yet; using the depth attachment and ignoring the standalone stencil attachment for framebuffer %u",
+            MGLOG_E_ONCE("GetOrCreateRenderPass: separate depth/stencil attachments are not supported yet; using the depth attachment and ignoring the standalone stencil attachment for framebuffer %u",
                     fbo.GetExternalIndex());
         }
         if (selectedDepthStencilAttachment != nullptr) {
@@ -1223,7 +1225,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             depthAttachmentDescription.finalLayout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;
             depthAttachmentDescription.initialLayout = loadInfo.initialLayout;
             if (trackedDepthLayout == VK_IMAGE_LAYOUT_UNDEFINED && (!clearDepth || !clearStencil)) {
-                MGLOG_W("GetOrCreateRenderPass: depth/stencil attachment id=%d starts with undefined layout "
+                MGLOG_W_ONCE("GetOrCreateRenderPass: depth/stencil attachment id=%d starts with undefined layout "
                         "and partial/no clear; using DONT_CARE for uncleared aspects",
                         depthAttachmentId);
             }
@@ -1507,7 +1509,23 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             ClearAttachmentPayload clearPayload{};
             SharedPtr<MG_State::GLState::ITextureObject> liveTexture;
             if (pending.hasInlinePayload) {
-                clearPayload = pending.inlinePayload;
+                // The inline payload was snapshotted when the entry was CREATED, but the
+                // clear VALUE is not part of the entry's hash - a cache hit with a newer
+                // glClear would replay the creation-time value and drop the new one (the
+                // texture path below is immune because it re-reads the live payload).
+                // Same defense as ClearAttachmentsOnActiveRenderPass: prefer the live
+                // pending clear, fall back to the snapshot only when none is queued.
+                if (s_renderPassManager != nullptr &&
+                    s_renderPassManager->GetPendingRenderbufferClear(pending.renderbuffer, clearPayload)) {
+                    if ((clearPayload.mask & GL_COLOR_BUFFER_BIT) != 0 && pending.renderbuffer != nullptr &&
+                        MG_Util::GetBaseInternalFormatComponentCount(pending.renderbuffer->GetInternalFormat()) ==
+                            3) {
+                        // RGB renderbuffers are backed by an RGBA image; the missing alpha reads as 1.
+                        ForceOpaqueClearAlpha(clearPayload);
+                    }
+                } else {
+                    clearPayload = pending.inlinePayload;
+                }
             } else {
                 if (pending.key.texture == nullptr ||
                     !s_clearManager->GetPendingClear(pending.key, clearPayload, liveTexture)) {

MobileGL/MG_Backend/DirectVulkan/Renderer/VkRenderPassManager.h

@@ -289,6 +289,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // or a pending clear. Portable to Vulkan 1.1 (no dynamic_rendering / imageless FB needed).
         Bool m_rpFastValid = false;
         const MG_State::GLState::FramebufferObject* m_rpFastFbo = nullptr;
+        // The FBO's never-reused lifetime id joins the raw pointer + Uint16 version:
+        // a deleted FBO reallocated at the same address whose fresh setup performed
+        // the same number of version bumps would otherwise compare equal (both count
+        // from 0), serving the dead framebuffer's pass to the new object.
+        Uint64 m_rpFastFboLifetimeId = 0;
         Uint16 m_rpFastFboVersion = 0;
         Uint32 m_rpFastSwapchainIndex = 0;
         Uint64 m_rpFastTexEpoch = 0;

MobileGL/MG_Backend/DirectVulkan/Renderer/VkTextureManager.cpp

@@ -300,8 +300,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Bool ok = VkTextureManager::TransitionImageLayout(
             commandBuffer, newResource.image, newResource.layout, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
             VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT,
-            0, VK_ACCESS_TRANSFER_WRITE_BIT, newResource.aspect, 0, newResource.mipLevels,
-            newResource.arrayLayers);
+            0, VK_ACCESS_TRANSFER_WRITE_BIT, newResource.aspect, 0, newResource.mipLevels);
         MOBILEGL_ASSERT(ok, "PreserveTextureContentsOnRecreate: failed to prepare destination image");
 
         VkImageLayout srcTrackedLayout = oldResource.layout;
@@ -311,8 +310,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         ok = VkTextureManager::TransitionImageLayout(
             commandBuffer, oldResource.image, srcTrackedLayout, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
             srcStageMask, VK_PIPELINE_STAGE_TRANSFER_BIT,
-            srcAccessMask, VK_ACCESS_TRANSFER_READ_BIT, oldResource.aspect, 0, preservedMipLevels,
-            oldResource.arrayLayers);
+            srcAccessMask, VK_ACCESS_TRANSFER_READ_BIT, oldResource.aspect, 0, preservedMipLevels);
         MOBILEGL_ASSERT(ok, "PreserveTextureContentsOnRecreate: failed to prepare source image");
 
         Vector<VkImageCopy> copyRegions;
@@ -344,8 +342,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         ok = VkTextureManager::TransitionImageLayout(
             commandBuffer, newResource.image, newResource.layout, oldResource.layout,
             VK_PIPELINE_STAGE_TRANSFER_BIT, dstStageMask,
-            VK_ACCESS_TRANSFER_WRITE_BIT, dstAccessMask, newResource.aspect, 0, newResource.mipLevels,
-            newResource.arrayLayers);
+            VK_ACCESS_TRANSFER_WRITE_BIT, dstAccessMask, newResource.aspect, 0, newResource.mipLevels);
         MOBILEGL_ASSERT(ok, "PreserveTextureContentsOnRecreate: failed to restore destination layout");
 
         VK_VERIFY(vkEndCommandBuffer(commandBuffer), "vkEndCommandBuffer(texture preserve)");
@@ -975,13 +972,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             return resource->sampledView;
         }
         if (!AreSampledImageViewFormatsCompatible(resource->format, format)) {
-            MGLOG_E("%s: incompatible sampled image view format=%d for textureId=%d imageFormat=%d",
+            MGLOG_E_ONCE("%s: incompatible sampled image view format=%d for textureId=%d imageFormat=%d",
                     __func__, static_cast<Int>(format), texture.GetExternalIndex(),
                     static_cast<Int>(resource->format));
             return VK_NULL_HANDLE;
         }
         if ((resource->imageCreateFlags & VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT) == 0) {
-            MGLOG_E("%s: textureId=%d needs mutable image format=%d for sampled view format=%d",
+            MGLOG_E_ONCE("%s: textureId=%d needs mutable image format=%d for sampled view format=%d",
                     __func__, texture.GetExternalIndex(), static_cast<Int>(resource->format),
                     static_cast<Int>(format));
             return VK_NULL_HANDLE;
@@ -1001,7 +998,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         VkFormatProperties formatProperties{};
         vkGetPhysicalDeviceFormatProperties(m_physicalDevice, format, &formatProperties);
         if ((formatProperties.optimalTilingFeatures & VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT) == 0) {
-            MGLOG_E("%s: sampled image view format=%d lacks VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT "
+            MGLOG_E_ONCE("%s: sampled image view format=%d lacks VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT "
                     "for textureId=%d (available=0x%x)",
                     __func__, static_cast<Int>(format), texture.GetExternalIndex(),
                     static_cast<Uint32>(formatProperties.optimalTilingFeatures));
@@ -1015,7 +1012,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             resource->sampledBaseMipLevel, resource->sampledLevelCount, 0, resource->arrayLayers,
             &sampledComponents, VK_IMAGE_USAGE_SAMPLED_BIT);
         if (view == VK_NULL_HANDLE) {
-            MGLOG_E("%s: failed to create sampled image view textureId=%d imageFormat=%d viewFormat=%d",
+            MGLOG_E_ONCE("%s: failed to create sampled image view textureId=%d imageFormat=%d viewFormat=%d",
                     __func__, texture.GetExternalIndex(), static_cast<Int>(resource->format),
                     static_cast<Int>(format));
             return VK_NULL_HANDLE;
@@ -1043,14 +1040,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             format = resource->format;
         }
         if (!AreStorageImageViewFormatsCompatible(resource->format, format)) {
-            MGLOG_E("%s: incompatible storage image view format=%d for textureId=%d imageFormat=%d",
+            MGLOG_E_ONCE("%s: incompatible storage image view format=%d for textureId=%d imageFormat=%d",
                     __func__, static_cast<Int>(format), texture.GetExternalIndex(),
                     static_cast<Int>(resource->format));
             return VK_NULL_HANDLE;
         }
         if (format != resource->format &&
             (resource->imageCreateFlags & VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT) == 0) {
-            MGLOG_E("%s: textureId=%d needs mutable image format=%d for storage view format=%d",
+            MGLOG_E_ONCE("%s: textureId=%d needs mutable image format=%d for storage view format=%d",
                     __func__, texture.GetExternalIndex(), static_cast<Int>(resource->format),
                     static_cast<Int>(format));
             return VK_NULL_HANDLE;
@@ -1070,7 +1067,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 viewType = VK_IMAGE_VIEW_TYPE_2D;
                 break;
             case VK_IMAGE_VIEW_TYPE_3D:
-                MGLOG_E("%s: non-layered 3D storage views are unsupported for textureId=%d",
+                MGLOG_E_ONCE("%s: non-layered 3D storage views are unsupported for textureId=%d",
                         __func__, texture.GetExternalIndex());
                 return VK_NULL_HANDLE;
             default:
@@ -1079,7 +1076,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
             if (viewType != resource->viewType) {
                 if (layer < 0 || static_cast<Uint32>(layer) >= resource->arrayLayers) {
-                    MGLOG_E("%s: storage image layer=%d is out of range for textureId=%d arrayLayers=%u",
+                    MGLOG_E_ONCE("%s: storage image layer=%d is out of range for textureId=%d arrayLayers=%u",
                             __func__, layer, texture.GetExternalIndex(), resource->arrayLayers);
                     return VK_NULL_HANDLE;
                 }
@@ -1114,7 +1111,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         VkFormatProperties formatProperties{};
         vkGetPhysicalDeviceFormatProperties(m_physicalDevice, format, &formatProperties);
         if ((formatProperties.optimalTilingFeatures & requiredFormatFeatures) != requiredFormatFeatures) {
-            MGLOG_E("%s: storage image view format=%d lacks required features=0x%x for textureId=%d "
+            MGLOG_E_ONCE("%s: storage image view format=%d lacks required features=0x%x for textureId=%d "
                     "(available=0x%x)",
                     __func__, static_cast<Int>(format), static_cast<Uint32>(requiredFormatFeatures),
                     texture.GetExternalIndex(), static_cast<Uint32>(formatProperties.optimalTilingFeatures));
@@ -1125,7 +1122,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                                  mipLevel, 1, baseArrayLayer, layerCount, nullptr,
                                                  VK_IMAGE_USAGE_STORAGE_BIT);
         if (view == VK_NULL_HANDLE) {
-            MGLOG_E("%s: failed to create storage image view for textureId=%d mip=%u imageFormat=%d viewFormat=%d",
+            MGLOG_E_ONCE("%s: failed to create storage image view for textureId=%d mip=%u imageFormat=%d viewFormat=%d",
                     __func__, texture.GetExternalIndex(), mipLevel, static_cast<Int>(resource->format),
                     static_cast<Int>(format));
             return VK_NULL_HANDLE;
@@ -1191,7 +1188,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 const Bool lowerTransitioned = TransitionImageLayout(
                     commandBuffer, resource.image, lowerMipLayout, newLayout,
                     srcStageMask, dstStageMask, srcAccessMask, dstAccessMask,
-                    resource.aspect, 0, writtenMipLevel, resource.arrayLayers);
+                    resource.aspect, 0, writtenMipLevel);
                 MOBILEGL_ASSERT(lowerTransitioned,
                                 "UpdateTrackedImageLayoutAfterAttachmentWrite: failed to transition lower mip levels for textureId=%d",
                                 texture->GetExternalIndex());
@@ -1203,8 +1200,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 const Bool upperTransitioned = TransitionImageLayout(
                     commandBuffer, resource.image, upperMipLayout, newLayout,
                     srcStageMask, dstStageMask, srcAccessMask, dstAccessMask,
-                    resource.aspect, upperBaseMipLevel, resource.mipLevels - upperBaseMipLevel,
-                    resource.arrayLayers);
+                    resource.aspect, upperBaseMipLevel, resource.mipLevels - upperBaseMipLevel);
                 MOBILEGL_ASSERT(upperTransitioned,
                                 "UpdateTrackedImageLayoutAfterAttachmentWrite: failed to transition upper mip levels for textureId=%d",
                                 texture->GetExternalIndex());
@@ -1223,7 +1219,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             return true;
         }
         if (resource->layout == VK_IMAGE_LAYOUT_UNDEFINED) {
-            MGLOG_W("TransitionTextureForSampling: textureId=%d is still in VK_IMAGE_LAYOUT_UNDEFINED before sampling",
+            MGLOG_W_ONCE("TransitionTextureForSampling: textureId=%d is still in VK_IMAGE_LAYOUT_UNDEFINED before sampling",
                     texture.GetExternalIndex());
         }
 
@@ -1257,8 +1253,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         const Bool ok = TransitionImageLayout(commandBuffer, resource->image, resource->layout, targetLayout, srcStageMask,
                                               s_sampledReadStages, srcAccessMask,
-                                              VK_ACCESS_SHADER_READ_BIT, resource->aspect, 0, resource->mipLevels,
-                                              resource->arrayLayers);
+                                              VK_ACCESS_SHADER_READ_BIT, resource->aspect, 0, resource->mipLevels);
         MOBILEGL_ASSERT(ok, "TransitionTextureForSampling: transition failed for textureId=%d", texture.GetExternalIndex());
         // Pre-pass stream bookkeeping: a command referencing the image was recorded.
         StampResourceRecordingUse(*resource);
@@ -1288,7 +1283,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                               VK_IMAGE_LAYOUT_GENERAL, srcStageMask,
                                               VK_PIPELINE_STAGE_ALL_COMMANDS_BIT, srcAccessMask,
                                               VK_ACCESS_SHADER_READ_BIT | VK_ACCESS_SHADER_WRITE_BIT,
-                                              resource->aspect, 0, resource->mipLevels, resource->arrayLayers);
+                                              resource->aspect, 0, resource->mipLevels);
         MOBILEGL_ASSERT(ok, "TransitionTextureForStorageImage: transition failed for textureId=%d",
                         texture.GetExternalIndex());
         // Pre-pass stream bookkeeping: a command referencing the image was recorded.
@@ -1296,6 +1291,158 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return ok;
     }
 
+    Bool VkTextureManager::SnapshotTextureForSampling(VkCommandBuffer commandBuffer,
+                                                      MG_State::GLState::ITextureObject& texture,
+                                                      SamplerNumericDomain numericDomain,
+                                                      VkPipelineStageFlags consumerShaderStageMask,
+                                                      SampledTextureSnapshot& outSnapshot) {
+        outSnapshot = {};
+        TextureResource* source = SyncTextureAndGetDescriptor(texture);
+        if (source == nullptr || source->image == VK_NULL_HANDLE || source->sampleCount != VK_SAMPLE_COUNT_1_BIT ||
+            source->sampledLevelCount == 0) {
+            return false;
+        }
+
+        const VkFormat sampledFormat = ResolveSampledImageViewFormat(source->format, numericDomain);
+        if (sampledFormat == VK_FORMAT_UNDEFINED ||
+            !AreSampledImageViewFormatsCompatible(source->format, sampledFormat)) {
+            MGLOG_E_ONCE("SnapshotTextureForSampling: textureId=%d cannot create sampled view format=%d from image format=%d",
+                         texture.GetExternalIndex(), static_cast<Int>(sampledFormat), static_cast<Int>(source->format));
+            return false;
+        }
+        if (sampledFormat != source->format &&
+            (source->imageCreateFlags & VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT) == 0) {
+            MGLOG_E_ONCE("SnapshotTextureForSampling: textureId=%d needs unavailable mutable image format=%d for sampled view=%d",
+                         texture.GetExternalIndex(), static_cast<Int>(source->format), static_cast<Int>(sampledFormat));
+            return false;
+        }
+
+        VkImageType imageType = VK_IMAGE_TYPE_2D;
+        switch (source->viewType) {
+        case VK_IMAGE_VIEW_TYPE_1D:
+        case VK_IMAGE_VIEW_TYPE_1D_ARRAY:
+            imageType = VK_IMAGE_TYPE_1D;
+            break;
+        case VK_IMAGE_VIEW_TYPE_3D:
+            imageType = VK_IMAGE_TYPE_3D;
+            break;
+        default:
+            break;
+        }
+
+        TextureResource snapshot{};
+        VkImageCreateInfo imageInfo{};
+        imageInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
+        imageInfo.flags = source->imageCreateFlags;
+        imageInfo.imageType = imageType;
+        imageInfo.extent = {source->extent.width, source->extent.height, source->depth};
+        imageInfo.mipLevels = source->mipLevels;
+        imageInfo.arrayLayers = source->arrayLayers;
+        imageInfo.format = source->format;
+        imageInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
+        imageInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
+        imageInfo.usage = VK_IMAGE_USAGE_TRANSFER_DST_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
+        imageInfo.samples = VK_SAMPLE_COUNT_1_BIT;
+        imageInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
+
+        // Keep the temporary's view-format list just as narrow as the source's sampler use. This
+        // has no storage-image usage, so unlike an app image binding the exact list is knowable.
+        Vector<VkFormat> viewFormats;
+        VkImageFormatListCreateInfo formatListInfo{};
+        if (m_imageFormatListSupported && (imageInfo.flags & VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT) != 0) {
+            viewFormats.push_back(source->format);
+            if (sampledFormat != source->format) {
+                viewFormats.push_back(sampledFormat);
+            }
+            formatListInfo.sType = VK_STRUCTURE_TYPE_IMAGE_FORMAT_LIST_CREATE_INFO;
+            formatListInfo.viewFormatCount = static_cast<Uint32>(viewFormats.size());
+            formatListInfo.pViewFormats = viewFormats.data();
+            imageInfo.pNext = &formatListInfo;
+        }
+
+        VmaAllocationCreateInfo allocationInfo{};
+        allocationInfo.usage = VMA_MEMORY_USAGE_AUTO_PREFER_DEVICE;
+        allocationInfo.requiredFlags = VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT;
+        const VkResult createResult =
+            vmaCreateImage(m_allocator, &imageInfo, &allocationInfo, &snapshot.image, &snapshot.allocation, nullptr);
+        if (createResult != VK_SUCCESS) {
+            MGLOG_E_ONCE("SnapshotTextureForSampling: vmaCreateImage failed result=%d textureId=%d", createResult,
+                         texture.GetExternalIndex());
+            return false;
+        }
+
+        snapshot.extent = source->extent;
+        snapshot.depth = source->depth;
+        snapshot.arrayLayers = source->arrayLayers;
+        snapshot.mipLevels = source->mipLevels;
+        snapshot.sampledBaseMipLevel = source->sampledBaseMipLevel;
+        snapshot.sampledLevelCount = source->sampledLevelCount;
+        snapshot.format = source->format;
+        snapshot.aspect = source->aspect;
+        snapshot.viewType = source->viewType;
+        snapshot.sampleCount = VK_SAMPLE_COUNT_1_BIT;
+        snapshot.imageCreateFlags = imageInfo.flags;
+        snapshot.usageFlags = imageInfo.usage;
+
+        const TextureFormatInfo formatInfo = ResolveTextureFormatInfo(texture.GetFormat());
+        const VkComponentMapping sampledComponents = ResolveSampledViewComponents(texture, formatInfo);
+        const VkImageAspectFlags sampledAspect =
+            ResolveSampledImageViewAspectMask(snapshot.aspect, texture.GetDepthStencilTextureMode());
+        snapshot.sampledView = CreateImageView(snapshot.image, sampledFormat, sampledAspect, snapshot.viewType,
+                                               snapshot.sampledBaseMipLevel, snapshot.sampledLevelCount, 0,
+                                               snapshot.arrayLayers, &sampledComponents);
+        if (snapshot.sampledView == VK_NULL_HANDLE) {
+            MGLOG_E_ONCE("SnapshotTextureForSampling: failed to create sampled view textureId=%d", texture.GetExternalIndex());
+            return false;
+        }
+
+        VkPipelineStageFlags sourceStageMask = VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT;
+        VkAccessFlags sourceAccessMask = 0;
+        const VkImageLayout sourceLayout = source->layout;
+        GetImageTransitionSourceState(sourceLayout, sourceStageMask, sourceAccessMask);
+        if (!TransitionImageLayout(commandBuffer, source->image, source->layout, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
+                                   sourceStageMask, VK_PIPELINE_STAGE_TRANSFER_BIT, sourceAccessMask,
+                                   VK_ACCESS_TRANSFER_READ_BIT, source->aspect, 0, source->mipLevels) ||
+            !TransitionImageLayout(commandBuffer, snapshot.image, snapshot.layout, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
+                                   VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0,
+                                   VK_ACCESS_TRANSFER_WRITE_BIT, snapshot.aspect, snapshot.sampledBaseMipLevel,
+                                   snapshot.sampledLevelCount)) {
+            return false;
+        }
+
+        Vector<VkImageCopy> copyRegions;
+        copyRegions.reserve(snapshot.sampledLevelCount);
+        for (Uint32 level = snapshot.sampledBaseMipLevel;
+             level < snapshot.sampledBaseMipLevel + snapshot.sampledLevelCount; ++level) {
+            VkImageCopy copy{};
+            copy.srcSubresource = {source->aspect, level, 0, source->arrayLayers};
+            copy.dstSubresource = {snapshot.aspect, level, 0, snapshot.arrayLayers};
+            copy.extent = {std::max(source->extent.width >> level, 1u),
+                           std::max(source->extent.height >> level, 1u),
+                           std::max(source->depth >> level, 1u)};
+            copyRegions.push_back(copy);
+        }
+        vkCmdCopyImage(commandBuffer, source->image, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL, snapshot.image,
+                       VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, static_cast<Uint32>(copyRegions.size()), copyRegions.data());
+
+        if (!TransitionImageLayout(commandBuffer, snapshot.image, snapshot.layout,
+                                   ResolveSampledReadOnlyLayout(snapshot.aspect), VK_PIPELINE_STAGE_TRANSFER_BIT,
+                                   consumerShaderStageMask, VK_ACCESS_TRANSFER_WRITE_BIT,
+                                   VK_ACCESS_SHADER_READ_BIT, snapshot.aspect, snapshot.sampledBaseMipLevel,
+                                   snapshot.sampledLevelCount) ||
+            !TransitionImageLayout(commandBuffer, source->image, source->layout, sourceLayout,
+                                   VK_PIPELINE_STAGE_TRANSFER_BIT, consumerShaderStageMask,
+                                   VK_ACCESS_TRANSFER_READ_BIT, VK_ACCESS_SHADER_READ_BIT | VK_ACCESS_SHADER_WRITE_BIT,
+                                   source->aspect, 0, source->mipLevels)) {
+            return false;
+        }
+
+        StampResourceRecordingUse(*source);
+        outSnapshot = {.imageView = snapshot.sampledView, .layout = snapshot.layout};
+        DeferResourceRelease(Move(snapshot));
+        return true;
+    }
+
     void VkTextureManager::MarkStorageImageTexture(MG_State::GLState::ITextureObject& texture) {
         m_storageImageTextures.insert(MakeTextureIdentity(&texture));
     }
@@ -1347,6 +1494,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const auto* mipTexture = MG_State::GLState::AsMipmapTexture(&texture);
         const Uint32 mipLevelCount = mipTexture != nullptr ? mipTexture->GetMipmapLevelCount() : 0u;
         return resource.syncedContentVersion != texture.GetContentVersion() ||
+               resource.syncedShapeVersion != texture.GetShapeVersion() ||
                resource.syncedTextureParamsVersion != texture.GetTextureParamsVersion() ||
                resource.syncedMipLevelCount != mipLevelCount;
     }
@@ -1355,8 +1503,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                                  VkImageLayout& trackedLayout, VkImageLayout newLayout,
                                                  VkPipelineStageFlags srcStageMask, VkPipelineStageFlags dstStageMask,
                                                  VkAccessFlags srcAccessMask, VkAccessFlags dstAccessMask,
-                                                 VkImageAspectFlags aspectMask, Uint32 baseMipLevel, Uint32 levelCount,
-                                                 Uint32 layerCount) {
+                                                 VkImageAspectFlags aspectMask, Uint32 baseMipLevel,
+                                                 Uint32 levelCount) {
         MOBILEGL_ASSERT(image != VK_NULL_HANDLE, "TransitionImageLayout: m_image == VK_NULL_HANDLE");
         MOBILEGL_ASSERT(!((dstAccessMask & VK_ACCESS_TRANSFER_READ_BIT) != 0 &&
                           (dstStageMask & VK_PIPELINE_STAGE_TRANSFER_BIT) == 0),
@@ -1381,7 +1529,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         barrier.subresourceRange.baseMipLevel = baseMipLevel;
         barrier.subresourceRange.levelCount = levelCount;
         barrier.subresourceRange.baseArrayLayer = 0;
-        barrier.subresourceRange.layerCount = layerCount;
+        // Every layer, always - see the declaration for why layout tracking leaves no other
+        // correct answer. VK_REMAINING_ARRAY_LAYERS rather than the image's own `arrayLayers`
+        // because those are not the same number for a 3D image: MobileGL creates 3D images
+        // 2D_ARRAY_COMPATIBLE and their arrayLayers is 1, which today Vulkan reads as "all depth
+        // slices" but will read as "depth slice 0" once VK_KHR_maintenance9 is enabled. The
+        // validation layer warns about that literal 1 by name.
+        barrier.subresourceRange.layerCount = VK_REMAINING_ARRAY_LAYERS;
         vkCmdPipelineBarrier(commandBuffer, srcStageMask, dstStageMask, 0, 0, nullptr, 0, nullptr, 1, &barrier);
 
         trackedLayout = newLayout;
@@ -1440,11 +1594,16 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     Bool VkTextureManager::SyncTexture(MG_State::GLState::ITextureObject &texture,
                                        TextureResource &outResource) {
         // Cross-draw fast path: if the resource is already built and neither the texture's
-        // pixel content (bumped in MarkStorageDirty) nor its params changed since the last
-        // sync, there is nothing to re-check or re-upload - skip CheckMipmapCompleteness,
-        // SyncTextureResource, SyncTextureViews and the per-level dirty scan. Layout is
-        // maintained separately by the transition path, so the resource still reflects truth.
+        // pixel content (bumped in MarkStorageDirty), its SHAPE (bumped in BumpShapeVersion)
+        // nor its params changed since the last sync, there is nothing to re-check or
+        // re-upload - skip CheckMipmapCompleteness, SyncTextureResource, SyncTextureViews and
+        // the per-level dirty scan. Layout is maintained separately by the transition path, so
+        // the resource still reflects truth. The shape version is NOT redundant with the
+        // content one: glTexImage2D(..., nullptr) re-specifies a level's size or format
+        // without dirtying a texel, which is exactly how a re-specified image-unit texture used
+        // to keep reporting its old imageSize().
         const Uint64 syncingContentVersion = texture.GetContentVersion();
+        const Uint64 syncingShapeVersion = texture.GetShapeVersion();
         const auto* syncingMipTexture = MG_State::GLState::AsMipmapTexture(&texture);
         const Uint32 syncingMipLevelCount =
             syncingMipTexture != nullptr ? syncingMipTexture->GetMipmapLevelCount() : 0u;
@@ -1456,6 +1615,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             m_storageImageTextures.find(MakeTextureIdentity(&texture)) != m_storageImageTextures.end();
         if (outResource.image != VK_NULL_HANDLE && !storageUpgradePending &&
             outResource.syncedContentVersion == syncingContentVersion &&
+            outResource.syncedShapeVersion == syncingShapeVersion &&
             outResource.syncedTextureParamsVersion == texture.GetTextureParamsVersion() &&
             outResource.syncedMipLevelCount == syncingMipLevelCount) {
             return true;
@@ -1476,6 +1636,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             return false;
         }
 
+        // From here down the size is VULKAN geometry, not GL's: a 1D array's layer count moves
+        // out of the height it occupies GL-side and into z, which is the slot
+        // TryResolveTextureShapeInfo reads arrayLayers from and the only one that leaves
+        // extent.height at the 1 a VK_IMAGE_TYPE_1D image is required to have.
+        texelSize = ToVulkanLevelExtent(texture.GetTarget(), texelSize);
+
         if (!SyncTextureResource(texture, uploadTarget, texelSize, byteSize, mipLevelCount, outResource)) {
             MGLOG_D("%s: SyncTextureResource failed", __func__);
             return false;
@@ -1507,6 +1673,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         if (!hasDirtyMipLevel) {
             outResource.syncedContentVersion = syncingContentVersion;
             outResource.syncedMipLevelCount = syncingMipLevelCount;
+            outResource.syncedShapeVersion = syncingShapeVersion;
             return true;
         }
 
@@ -1516,6 +1683,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
         outResource.syncedContentVersion = syncingContentVersion;
         outResource.syncedMipLevelCount = syncingMipLevelCount;
+        outResource.syncedShapeVersion = syncingShapeVersion;
         return true;
     }
 
@@ -1574,7 +1742,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // targets this manager has no Vulkan image shape for yet (cube map arrays above all).
             // Declining the sync leaves the texture unbacked - wrong, but recoverable - where an
             // assertion would take the whole process down instead.
-            MGLOG_W("SyncTextureResource: unsupported uploadTarget=%s textureTarget=%s textureId=%d size=(%d,%d,%d) "
+            MGLOG_W_ONCE("SyncTextureResource: unsupported uploadTarget=%s textureTarget=%s textureId=%d size=(%d,%d,%d) "
                     "mipLevels=%u vkViewType=%d",
                     MG_Util::ConvertTextureUploadTargetToString(uploadTarget).c_str(),
                     MG_Util::ConvertTextureTargetToString(texture.GetTarget()).c_str(), texture.GetExternalIndex(),
@@ -1695,6 +1863,19 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                         }
                     }
                 }
+                if (rounded == 0 && (supported & VK_SAMPLE_COUNT_1_BIT) != 0) {
+                    // Nothing at two samples or above. Reachable because the frontend validates
+                    // multisample allocations against the count MobileGL ADVERTISES (GL requires
+                    // GL_MAX_SAMPLES >= 4) rather than against the device's per-format support, so
+                    // a format this device cannot multisample at all now gets here instead of
+                    // being refused up front. Keeping the unsupported count would hand
+                    // vkCreateImage an invalid VkImageCreateInfo; one sample is at least a legal
+                    // image, and the samples-08726 hazard above is the lesser of the two.
+                    MGLOG_W_ONCE("Multisample texture format %d supports no count above one on this device; "
+                                 "backing it with a single sample",
+                                 static_cast<Int>(format));
+                    rounded = static_cast<Uint32>(VK_SAMPLE_COUNT_1_BIT);
+                }
                 if (rounded != 0) {
                     resolvedSampleCount = static_cast<VkSampleCountFlagBits>(rounded);
                 }
@@ -1803,7 +1984,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 // Losing reinterpreted views only degrades the formatless-image feature for
                 // this texture; failing creation would lose the texture entirely, so retry
                 // as a plain immutable-format image.
-                MGLOG_W("%s: mutable image format=%d is unsupported for textureId=%d; creating "
+                MGLOG_W_ONCE("%s: mutable image format=%d is unsupported for textureId=%d; creating "
                         "without VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT (format reinterpretation "
                         "will be unavailable for it)",
                         __func__, static_cast<Int>(format), texture.GetExternalIndex());
@@ -1821,7 +2002,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 // Losing 2D-array compatibility only costs per-slice framebuffer attachment for this
                 // format; failing creation would lose the texture entirely. Remembered so later syncs
                 // neither reprobe nor flag-mismatch against this image and recreate it.
-                MGLOG_W("%s: VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT is unsupported for format=%d "
+                MGLOG_W_ONCE("%s: VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT is unsupported for format=%d "
                         "textureId=%d; creating without it (per-slice framebuffer attachment will be "
                         "unavailable for it)",
                         __func__, static_cast<Int>(format), texture.GetExternalIndex());
@@ -1840,6 +2021,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                         texture.GetExternalIndex(),
                         MG_Util::ConvertTextureUploadTargetToString(uploadTarget).c_str(),
                         static_cast<Int>(format), static_cast<Uint32>(imageInfo.usage));
+                // The preserved image was written by GPU work that may still be in flight
+                // (preserve requires layout != UNDEFINED); park it on the deferred ring
+                // like every other destruction path instead of letting the unique_ptr
+                // destroy it synchronously under the GPU.
+                if (preservedResource) {
+                    DeferResourceRelease(Move(*preservedResource));
+                }
                 return false;
             }
         }
@@ -1853,13 +2041,21 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const VkResult createImageResult =
             vmaCreateImage(m_allocator, &imageInfo, &allocationInfo, &resource.image, &resource.allocation, nullptr);
         if (createImageResult != VK_SUCCESS) {
-            MGLOG_F("SyncTextureResource: vmaCreateImage failed (%d) textureId=%d extent=%ux%u depth=%u layers=%u "
+            // E_ONCE, not F: the comment above says it - this is a soft failure the caller
+            // recovers from, and it re-fires on every sync of every texture the driver refuses.
+            MGLOG_E_ONCE("SyncTextureResource: vmaCreateImage failed (%d) textureId=%d extent=%ux%u depth=%u layers=%u "
                     "mips=%u samples=%d format=%d",
                     createImageResult, texture.GetExternalIndex(), imageInfo.extent.width, imageInfo.extent.height,
                     imageInfo.extent.depth, imageInfo.arrayLayers, imageInfo.mipLevels,
                     static_cast<Int>(imageInfo.samples), static_cast<Int>(imageInfo.format));
             resource.image = VK_NULL_HANDLE;
             resource.allocation = nullptr;
+            // Same as the probe failure above: the preserved live image must go through
+            // the deferred ring, never a synchronous destructor while frames that
+            // reference it are still in flight.
+            if (preservedResource) {
+                DeferResourceRelease(Move(*preservedResource));
+            }
             return false;
         }
         ++m_textureImageEpoch; // a new attachment image invalidates cached render passes
@@ -2355,7 +2551,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 uploadItem.target = target;
                 uploadItem.level = level;
                 uploadItem.baseArrayLayer = ResolveUploadArrayLayer(target);
-                uploadItem.texelSize = texelSize;
+                // Vulkan geometry, like the image this stages into (see SyncTexture): a 1D
+                // array's layers move from y to z, where the copy loop's depthSelectsArrayLayer
+                // branch turns them into layerCount. The shadow needs no repacking to follow -
+                // one layer of a 1D array IS one row of `width` texels, so the tight-packed
+                // per-layer copy the swapped size describes reads the same bytes in the same
+                // order as the row-major level it replaces.
+                uploadItem.texelSize = ToVulkanLevelExtent(mipmapTexture.GetTarget(), texelSize);
                 uploadItem.source = source;
                 uploadItem.offset = stagingSize;
                 uploadItem.uploadByteSize = byteSize;
@@ -2393,6 +2595,23 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                             }
                             uploadItem.uploadByteSize = rectTexels * uploadItem.texelBytes;
                         }
+                        // The boxes came out of the shadow in GL coordinates, where a 1D
+                        // array's layer is the y. They have to follow texelSize across to z or
+                        // they would address rows of an image that now has exactly one, and
+                        // the staging walk would read the wrong bytes for them. Every byte
+                        // count computed above is a product of the three extents, so moving
+                        // the axes leaves all of them alone - and an OFFSET lands on a zero y,
+                        // not on the extent's one, which is why this is spelled out rather than
+                        // handed to ToVulkanLevelExtent.
+                        if (mipmapTexture.GetTarget() == TextureTarget::Texture1DArray) {
+                            uploadItem.regionLo = {uploadItem.regionLo.x(), 0, uploadItem.regionLo.y()};
+                            uploadItem.regionSize = {uploadItem.regionSize.x(), 1,
+                                                     uploadItem.regionSize.y()};
+                            for (auto& rect : uploadItem.rects) {
+                                rect.lo = {rect.lo.x(), 0, rect.lo.y()};
+                                rect.hi = {rect.hi.x(), 1, rect.hi.y()};
+                            }
+                        }
                     }
                 }
                 if (formatInfo.expandRgbToRgba) {
@@ -2426,7 +2645,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             const Bool srcIsD24S8 = outResource.format == VK_FORMAT_D24_UNORM_S8_UINT;
             const Bool srcIsD32FS8 = outResource.format == VK_FORMAT_D32_SFLOAT_S8_UINT;
             if (!srcIsD24S8 && !srcIsD32FS8) {
-                MGLOG_E("UploadDirtyMipLevels: unsupported combined depth-stencil format %d for textureId=%d",
+                MGLOG_E_ONCE("UploadDirtyMipLevels: unsupported combined depth-stencil format %d for textureId=%d",
                         static_cast<Int>(outResource.format), mipmapTexture.GetExternalIndex());
                 for (const auto& item : uploadItems) {
                     mipmapTexture.MarkStorageDirty(item.target, item.level, false);
@@ -2603,7 +2822,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                         VK_PIPELINE_STAGE_TRANSFER_BIT,
                                         uploadSrcAccessMask,
                                         VK_ACCESS_TRANSFER_WRITE_BIT,
-                                        aspectMask, 0, outResource.mipLevels, outResource.arrayLayers);
+                                        aspectMask, 0, outResource.mipLevels);
         MOBILEGL_ASSERT(ok, "TransitionImageLayout to VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL failed");
 
         // Array textures keep their GL "depth" in VkImage array layers, so the
@@ -2707,7 +2926,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                    s_sampledReadStages,
                                    VK_ACCESS_TRANSFER_WRITE_BIT,
                                    VK_ACCESS_SHADER_READ_BIT,
-                                   aspectMask, 0, outResource.mipLevels, outResource.arrayLayers);
+                                   aspectMask, 0, outResource.mipLevels);
         MOBILEGL_ASSERT(ok, "TransitionImageLayout to sampled read-only layout failed");
         outResource.layout = finalLayout;
 

MobileGL/MG_Backend/DirectVulkan/Renderer/VkTextureManager.h

@@ -22,6 +22,25 @@ class ITextureObject;
 namespace MobileGL::MG_Backend::DirectVulkan {
 enum class SamplerNumericDomain : Uint8;
 
+// A GL 1D-ARRAY level keeps its LAYER COUNT in the state-side HEIGHT: that is what
+// glTexImage2D(GL_TEXTURE_1D_ARRAY, width, layers) means, and the frontend records the level
+// as {width, layers, 1} (see GL_Texture.cpp's AllocateStorage and the completeness walk in
+// TextureObject.cpp, which shrinks only x down the chain). Vulkan packs it the other way: a
+// 1D array is a VK_IMAGE_TYPE_1D image whose extent.height MUST be 1 and whose layers live in
+// arrayLayers - i.e. in the slot this backend reads out of z. So every place that turns a GL
+// level size into Vulkan image geometry has to move the count across first, and every GL-space
+// sub-box that rides along with it has to move its y the same way. DirectGLES performs the
+// identical remap onto the ES 2D array it maps 1D arrays to (GetBackendUploadSize).
+//
+// Applied to nothing else: a 2D array, a cube array and a 3D texture all already carry their
+// depth/layer count in z, which is where the Vulkan side expects it.
+inline IntVec3 ToVulkanLevelExtent(TextureTarget stateTarget, const IntVec3& glTexelSize) {
+    if (stateTarget == TextureTarget::Texture1DArray) {
+        return {glTexelSize.x(), 1, glTexelSize.y()};
+    }
+    return glTexelSize;
+}
+
 class VkTextureManager {
 public:
     // Monotonic epoch bumped whenever a texture VkImage is (re)created. The render-pass
@@ -206,6 +225,12 @@ public:
         // as defense-in-depth: any path that grows the level set (which resizes the sampled view)
         // busts the skip even if it failed to bump the content version.
         Uint32 syncedMipLevelCount = 0;
+        // Snapshot of ITextureObject::GetShapeVersion() at the last successful sync. The content
+        // version alone does NOT cover a re-specification: glTexImage2D(..., nullptr) on an
+        // already-defined level changes its size or format and dirties no texel, so it moves the
+        // shape version and nothing else. Without this in the early-out key the image, its views
+        // and therefore imageSize() all keep answering with the texture's PREVIOUS shape.
+        Uint64 syncedShapeVersion = 0;
 
         TextureResource() = default;
         TextureResource(const TextureResource&) = delete;
@@ -237,6 +262,7 @@ public:
             std::swap(this->lastRecordingGeneration, that.lastRecordingGeneration);
             std::swap(this->syncedContentVersion, that.syncedContentVersion);
             std::swap(this->syncedMipLevelCount, that.syncedMipLevelCount);
+            std::swap(this->syncedShapeVersion, that.syncedShapeVersion);
         }
 
         void Reset() {
@@ -300,6 +326,7 @@ public:
             syncedTextureParamsVersion = 0;
             syncedContentVersion = 0;
             syncedMipLevelCount = 0;
+            syncedShapeVersion = 0;
         }
 
         ~TextureResource() {
@@ -310,6 +337,11 @@ public:
         static inline VmaAllocator s_allocator = VK_NULL_HANDLE;
     };
 
+    struct SampledTextureSnapshot {
+        VkImageView imageView = VK_NULL_HANDLE;
+        VkImageLayout layout = VK_IMAGE_LAYOUT_UNDEFINED;
+    };
+
     Bool Initialize(const InitInfo& initInfo);
     void Shutdown();
     void BeginFrame(Uint32 frameIndex);
@@ -343,6 +375,13 @@ public:
                                                       VkImageLayout newLayout);
     Bool TransitionTextureForSampling(VkCommandBuffer commandBuffer, MG_State::GLState::ITextureObject& texture);
     Bool TransitionTextureForStorageImage(VkCommandBuffer commandBuffer, MG_State::GLState::ITextureObject& texture);
+    // Copies the complete sampler-visible mip range into a transient sampled image. The source is
+    // restored to its prior layout, so image-store descriptors continue to name the original image.
+    // The transient ownership is tied to the current frame slot and is safe through its submission.
+    Bool SnapshotTextureForSampling(VkCommandBuffer commandBuffer, MG_State::GLState::ITextureObject& texture,
+                                    SamplerNumericDomain numericDomain,
+                                    VkPipelineStageFlags consumerShaderStageMask,
+                                    SampledTextureSnapshot& outSnapshot);
 
     // Recording-generation bookkeeping for the pre-pass command stream. The
     // generation advances every time the frame command buffer (re)begins
@@ -388,12 +427,24 @@ public:
     static Bool AreSampledImageViewFormatsCompatible(VkFormat imageFormat, VkFormat viewFormat);
     static Bool AreStorageImageViewFormatsCompatible(VkFormat imageFormat, VkFormat viewFormat);
 
+    // Moves `image` to `newLayout` and writes the new layout back through `trackedLayout`.
+    //
+    // The barrier covers EVERY array layer of the image, and there is deliberately no layer
+    // parameter to say otherwise: layout here is tracked per IMAGE (one `TextureResource::layout`,
+    // or one caller-owned variable), so a barrier narrower than the image would leave the layers it
+    // skipped in the old layout while the tracker claims they moved. Every transfer against a
+    // framebuffer attachment above layer 0 - glReadPixels, glBlitFramebuffer, glCopyTexSubImage,
+    // glCopyImageSubData - then ran its copy on a layer no barrier had transitioned.
+    //
+    // The mip range IS a parameter, because mip levels really are transitioned piecewise (see
+    // UpdateTrackedImageLayoutAfterAttachmentWrite and the mipmap generation loops): those callers
+    // move the complement of the level they wrote so the whole image converges on one layout again.
+    // Nothing does, or can, do that per layer.
     static Bool TransitionImageLayout(VkCommandBuffer commandBuffer, VkImage image, VkImageLayout& trackedLayout,
                                VkImageLayout newLayout, VkPipelineStageFlags srcStageMask,
                                VkPipelineStageFlags dstStageMask, VkAccessFlags srcAccessMask,
                                VkAccessFlags dstAccessMask, VkImageAspectFlags aspectMask,
-                               Uint32 baseMipLevel = 0, Uint32 levelCount = 1,
-                               Uint32 layerCount = 1);
+                               Uint32 baseMipLevel = 0, Uint32 levelCount = 1);
 
     SizeT CollectGarbage();
 

MobileGL/MG_Backend/DirectVulkan/Renderer/VkTimerQueryManager.cpp

@@ -15,7 +15,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         MOBILEGL_ASSERT(initInfo.device != VK_NULL_HANDLE, "VkTimerQueryManager::Initialize requires valid VkDevice");
         MOBILEGL_ASSERT(initInfo.frameCount > 0, "VkTimerQueryManager::Initialize requires non-zero frame count");
         if (initInfo.timestampValidBits == 0 || initInfo.timestampPeriodNs <= 0.0f || initInfo.slotsPerPool == 0) {
-            MGLOG_W("VkTimerQueryManager: timestamps unsupported (validBits=%u, period=%f, slots=%u)",
+            MGLOG_W_ONCE("VkTimerQueryManager: timestamps unsupported (validBits=%u, period=%f, slots=%u)",
                     initInfo.timestampValidBits, initInfo.timestampPeriodNs, initInfo.slotsPerPool);
             return false;
         }
@@ -35,7 +35,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         for (auto& poolState : m_pools) {
             const VkResult result = vkCreateQueryPool(m_device, &poolInfo, nullptr, &poolState.pool);
             if (result != VK_SUCCESS) {
-                MGLOG_E("VkTimerQueryManager: vkCreateQueryPool failed with %s", VkResultToString(result));
+                MGLOG_E_ONCE("VkTimerQueryManager: vkCreateQueryPool failed with %s", VkResultToString(result));
                 Shutdown();
                 return false;
             }
@@ -90,7 +90,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         auto& poolState = m_pools[frameIndex];
         if (poolState.cursor >= m_slotsPerPool) {
             if (!poolState.exhaustionWarned) {
-                MGLOG_W("VkTimerQueryManager: frame %u timestamp pool exhausted (%u slots); further timer queries "
+                MGLOG_W_ONCE("VkTimerQueryManager: frame %u timestamp pool exhausted (%u slots); further timer queries "
                         "this frame fall back to the frontend path",
                         frameIndex, m_slotsPerPool);
                 poolState.exhaustionWarned = true;
@@ -120,7 +120,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             m_device, m_pools[record.poolIndex].pool, record.slot, 1, sizeof(resultWithAvailability),
             resultWithAvailability, sizeof(Uint64), VK_QUERY_RESULT_64_BIT | VK_QUERY_RESULT_WITH_AVAILABILITY_BIT);
         if (result != VK_SUCCESS && result != VK_NOT_READY) {
-            MGLOG_E("VkTimerQueryManager: vkGetQueryPoolResults failed with %s", VkResultToString(result));
+            MGLOG_E_ONCE("VkTimerQueryManager: vkGetQueryPoolResults failed with %s", VkResultToString(result));
             return false;
         }
         if (resultWithAvailability[1] == 0) {

MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.h

@@ -23,6 +23,7 @@
 #include "VkTimerQueryManager.h"
 #include "MG_Util/Math/VectorTypes.h"
 #include <Includes.h>
+#include <MG_Backend/BackendObject.h>
 #include <vk_mem_alloc.h>
 
 #include "../VkIncludes.h"
@@ -197,9 +198,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                   GLbitfield mask, GLenum filter);
         void CopyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
                        GLint x, GLint y, GLsizei width, GLsizei height);
-        void CopyImageSubData(const SharedPtr<MG_State::GLState::ITextureObject>& srcTexture,
+        void CopyImageSubData(const CopyImageEndpoint& srcEndpoint,
                               GLenum srcTarget, GLint srcLevel, GLint srcX, GLint srcY, GLint srcZ,
-                              const SharedPtr<MG_State::GLState::ITextureObject>& dstTexture,
+                              const CopyImageEndpoint& dstEndpoint,
                               GLenum dstTarget, GLint dstLevel, GLint dstX, GLint dstY, GLint dstZ,
                               GLsizei srcWidth, GLsizei srcHeight, GLsizei srcDepth);
         void GenerateMipmap(GLenum target);
@@ -216,10 +217,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // depth/stencil image, which this renderer stores display-side-up: the copy rect then
         // has to be mapped out of GL's bottom-origin space and the copied rows re-oriented on
         // the way back, exactly as the colour ReadPixels path does.
+        // `sourceLayerCount` above 1 says the `height` rows the client is owed are stored as that
+        // many ARRAY LAYERS of a one-row image rather than as rows of one layer - the shape a GL
+        // 1D array has in Vulkan. The two produce byte-identical tightly-packed readbacks, so
+        // only the copy region differs; everything after it is written against `height`.
         void ReadDepthStencilImageToClient(VkImage image, VkFormat vkFormat, VkImageLayout* trackedLayout,
                                            VkImageAspectFlags imageAspect, Uint32 mipLevel, Uint32 baseArrayLayer,
                                            GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type,
-                                           void* pixels, Bool defaultFramebufferOrientation = false);
+                                           void* pixels, Bool defaultFramebufferOrientation = false,
+                                           Uint32 sourceLayerCount = 1);
         // Same-extent depth blit between images of different depth formats: host
         // round-trip with a per-texel re-encode (see BlitNamedFramebuffer).
         Bool BlitDepthAcrossFormats(FrameContext::FrameData& frame, VkImage srcImage, VkFormat srcFormat,
@@ -229,6 +235,18 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                     GLint dstY, GLint width, GLint height, VkImageLayout srcRestoreLayout,
                                     VkImageLayout dstRestoreLayout, Bool stencilAspect);
         static SizeT GetReadbackTexelSize(VkFormat sourceFormat);
+        // Map a GL bottom-left-origin rectangle into the display-oriented swapchain image.
+        // Quarter-turn surface transforms swap the copy extent's axes.
+        static Bool MapDefaultFramebufferReadbackRect(GLint x, GLint y, GLsizei width, GLsizei height,
+                                                      VkExtent2D imageExtent,
+                                                      VkSurfaceTransformFlagBitsKHR preTransform,
+                                                      VkOffset2D* imageOffset, VkExtent2D* imageCopyExtent);
+        // Reorder a tightly packed block copied with MapDefaultFramebufferReadbackRect back into
+        // GL row order. The input block has swapped dimensions for 90/270 degree transforms.
+        static Bool RemapDefaultFramebufferReadback(const Uint8* rawPixels, Uint32 logicalWidth,
+                                                    Uint32 logicalHeight,
+                                                    VkSurfaceTransformFlagBitsKHR preTransform,
+                                                    SizeT texelSize, Uint8* outPixels);
         static Bool ConvertReadbackPixels(const Uint8* sourcePixels, VkFormat sourceFormat,
                                           GLsizei width, GLsizei height, GLenum destinationFormat,
                                           GLenum destinationType, SizeT destinationRowStride,
@@ -298,6 +316,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // The samplerAnisotropy device feature was granted, so GL_TEXTURE_MAX_ANISOTROPY_EXT is
         // honored rather than accepted-and-ignored.
         Bool IsSamplerAnisotropySupported() const { return m_samplerAnisotropyFeatureEnabled; }
+        // ARB_base_instance extends indirect command records with a non-zero firstInstance and
+        // requires gl_InstanceID to remain zero-based. Vulkan needs both features to honor that
+        // complete contract: one legalizes the command word, the other enables the shader rebase.
+        Bool IsNonZeroIndirectBaseInstanceSupported() const {
+            return m_drawIndirectFirstInstanceFeatureEnabled && m_shaderDrawParametersFeatureEnabled;
+        }
         // Ensures the frame command buffer is recording (same lazy pattern as
         // SetupDraw) and writes a bottom-of-pipe timestamp into the current
         // frame's pool. Null when unsupported or the pool is exhausted.
@@ -536,7 +560,20 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Bool m_samplerAnisotropyFeatureEnabled = false;
         Bool m_shaderDrawParametersExtensionEnabled = false;
         Bool m_shaderDrawParametersFeatureEnabled = false;
+        // Native subgroup topology, queried at device creation for the compute-module
+        // subgroup repairs (SubgroupSupportPolicy.h) and the REQUIRE_FULL_SUBGROUPS
+        // stage flag; 0 / false when the device has no usable compute subgroups or
+        // MOBILEGL_DISABLE_SUBGROUP forced them off.
+        Uint32 m_nativeSubgroupSize = 0;
+        Bool m_nativeSubgroupSupported = false;
+        Bool m_computeFullSubgroupsFeatureEnabled = false;
+        // VkPhysicalDeviceSubgroupSizeControlProperties::maxComputeWorkgroupSubgroups;
+        // 0 when the extension (and therefore the full-subgroups flag) is unavailable.
+        Uint32 m_maxComputeWorkgroupSubgroups = 0;
         Bool m_unformattedFloatStorageImagesEnabled = false;
+        // Set only after descriptor-indexing feature AND property queries prove that
+        // update-after-bind is legal for every descriptor category this renderer emits.
+        ProgramFactory::UpdateAfterBindLimits m_updateAfterBindLimits{};
         // fillModeNonSolid gates VK_POLYGON_MODE_LINE/_POINT (glPolygonMode); independentBlend gates
         // per-draw-buffer color write masks (glColorMaski). Both are cached at device creation and
         // drive a runtime fallback when the device lacks them.
@@ -547,6 +584,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // needs no feature). Both cached at device creation and drive a hard-fail-at-draw when absent.
         Bool m_dualSrcBlendFeatureEnabled = false;
         Bool m_primitiveTopologyListRestartFeatureEnabled = false;
+        // multiViewport gates rasterizing into more than one of ARB_viewport_array's 16 viewports
+        // (gl_ViewportIndex). m_maxRasterizableViewports is min(MAX_VIEWPORTS, device limit), or 1
+        // when the feature is off, and is the viewportCount a gl_ViewportIndex-writing pipeline
+        // declares - it is NOT what GL_MAX_VIEWPORTS reports, which is the frontend state width.
+        Bool m_multiViewportFeatureEnabled = false;
+        Uint32 m_maxRasterizableViewports = 1;
         // Union of shader stages sampled-read barriers may name; built at device creation
         // because geometry/tessellation stage bits are invalid in a barrier when their
         // feature is off (VUID-vkCmdPipelineBarrier-srcStageMask-04090/-04091), and
@@ -770,6 +813,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Uint32 m_lastLodProgramVersion = 0;
         Uint64 m_lastLodBindGeneration = 0;
         Uint64 m_lastLodParamsSum = 0;
+        // Sampling-resolution generation at probe time. The probe reads the effective
+        // sampler's filters/aniso/LOD range, whose setters bump only this counter -
+        // the params-version sum above never moves for them.
+        Uint64 m_lastLodSamplingGeneration = 0;
         ProgramFactory::CompileOptionFlags m_lastLodBaseFlags = {};
         ProgramFactory::CompileOptionFlags m_lastLodResultFlags = {};
 
@@ -807,6 +854,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             Uint64 vaoLifetimeId = 0;
             Uint32 vaoConfigVersion = 0;
             const void* drawFbo = nullptr;
+            // Never-reused lifetime id beside the raw pointer + Uint16 version: a
+            // deleted FBO recycled at the same address with the same fresh version
+            // count would otherwise compare equal (same ABA as the render-pass
+            // manager's fast-path memo).
+            Uint64 drawFboLifetimeId = 0;
             Uint16 fboVersion = 0;
             Bool drawFboIsDefault = false;
             Uint renderStateVersion = 0;
@@ -830,6 +882,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // re-resolve just the pipeline against the active pass; a change that
             // flips it must fall back to the full path's pass selection.
             Bool drawUsesDepthStencil = false;
+            // The snapshotting draw's pipeline viewportCount. A pure function of the PROGRAM
+            // (writesViewportIndexBuiltin) and of a device feature fixed at renderer init, both
+            // of which the programLifetimeId/programVersion guards above already pin - carried
+            // here so the fast path does not re-fetch the program object to re-derive it.
+            Uint32 viewportCount = 1;
             IntVec2 renderPassExtent = {0, 0};
             // colorAttachmentCount of the snapshotting draw's render pass: the
             // pipeline-state hash input, so the fast path can refresh that hash and
@@ -897,6 +954,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // already sampleable.
         Vector<VkTextureManager::TextureResource*> m_sampledResourcesScratch;
         Vector<MG_State::GLState::ITextureObject*> m_storageImageTexturesScratch;
+        Vector<UniformManager::SamplerImageFeedbackBinding> m_samplerImageFeedbackScratch;
+        Vector<UniformManager::SamplerBindingOverride> m_samplerImageBindingOverridesScratch;
         Vector<VkBuffer> m_vertexBuffersScratch;
         Vector<VkDeviceSize> m_vertexOffsetsScratch;
         Vector<VkVertexInputAttributeDescription> m_patchedAttributesScratch;
@@ -1023,6 +1082,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             VkBuffer indexVkBuffer = VK_NULL_HANDLE;
             VkDeviceSize indexSliceOffset = 0;
             Uint64 indexFrameSerial = 0;
+            // The EBO carried a host map when the slice was recorded - the mirror of
+            // anyBufferMapped on the vertex half. A shadow-backed (non-adopted)
+            // persistent map mutates its shadow with no API call and no epoch bump, so
+            // the one-compare rescue must decline and re-run the acquire, whose
+            // SyncPersistentMappedRange is the push-down. A map taken AFTER the record
+            // is already covered: AcquirePersistentMap bumps the slice epoch for the
+            // request itself, adopted or declined.
+            Bool indexBufferMapped = false;
 
             // Bound per draw (first bindingCount elements).
             VkBuffer vkBuffers[kMaxBindings] = {};
@@ -1116,11 +1183,34 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             FrameContext::FrameData& frame,
             const MG_State::GLState::ProgramObject& program,
             const ProgramFactory::VkProgramObject& programObj);
+        // Vulkan forbids a sampled descriptor and writable storage descriptor from naming the
+        // same image subresource in one shader operation. Snapshot only the sampler side; the
+        // storage descriptor continues to name the application texture.
+        Bool PrepareSamplerImageFeedbackSnapshots(
+            FrameContext::FrameData& frame,
+            const MG_State::GLState::ProgramObject& program,
+            const ProgramFactory::VkProgramObject& programObj,
+            VkPipelineStageFlags consumerShaderStageMask);
 
         // The per-draw dynamic-state tail (viewport, scissor, blend constants, depth
         // bias, line width, stencil), gated behind one render-state-parameters-version
         // compare per command buffer - see the gate fields in DynamicStateShadow.
-        void ApplyDynamicDrawStateTail(FrameContext::FrameData& frame, const IntVec2& extent, Bool isDefaultFbo);
+        // viewportCount is the bound pipeline's declared viewport count: 1 for every program that
+        // does not write gl_ViewportIndex (the memoized fast path), otherwise the renderer's
+        // rasterizable viewport count, which takes the unmemoized array path.
+        void ApplyDynamicDrawStateTail(FrameContext::FrameData& frame, const IntVec2& extent, Bool isDefaultFbo,
+                                       Uint32 viewportCount = 1);
+        void ApplyMultiViewportDynamicState(VkCommandBuffer commandBuffer, Uint32 viewportCount, const IntVec2& extent,
+                                            VkSurfaceTransformFlagBitsKHR preTransform, Bool isDefaultFbo);
+        VkRect2D ComputeGLScissorRect(Uint32 index, const IntVec2& extent,
+                                      VkSurfaceTransformFlagBitsKHR preTransform, Bool isDefaultFbo) const;
+        // How many viewports a draw with this program rasterizes into: 1 unless the program
+        // assigns gl_ViewportIndex AND the device enabled multiViewport. Both the pipeline's
+        // baked viewportCount and the dynamic arrays come from this one answer, so they cannot
+        // disagree.
+        Uint32 ResolveDrawViewportCount(Bool programWritesViewportIndex) const {
+            return programWritesViewportIndex && m_multiViewportFeatureEnabled ? m_maxRasterizableViewports : 1u;
+        }
 
         Bool UploadAndBindVertexBuffers(VkCommandBuffer commandBuffer, const MG_State::GLState::VertexArrayObject& vao,
                                         const ProgramFactory::VkProgramObject& programObj,

MobileGL/MG_Backend/DirectVulkan/SubgroupSupportPolicy.h

@@ -0,0 +1,63 @@
+// MobileGL - MobileGL/MG_Backend/DirectVulkan/SubgroupSupportPolicy.h
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#pragma once
+
+#include <Config.h>
+#include <Includes.h>
+
+namespace MobileGL::MG_Backend::DirectVulkan {
+    // The single decision point for how DirectVulkan implements GL_KHR_shader_subgroup,
+    // shared by capability advertisement (BackendObject) and module lowering
+    // (VulkanRenderer / ProgramFactory) so the two can never disagree.
+    //
+    // Native subgroups are the implementation whenever the device has them, whatever
+    // their width - subgroup operations execute on the hardware paths they were made
+    // for. Module-level repairs keep the GL contract intact around them:
+    //   - FixIterationRPSubgroupScratchPass patches the one known pack bug: iterationRP's
+    //     prefixSumCache[32], under-declared for sub-16-lane devices (8-lane lavapipe);
+    //   - FixIterationRPBarrierPass repairs Program 203's race between two reductions
+    //     reusing that scratch, when explicitly enabled;
+    //   - DeriveNumSubgroupsPass replaces the one builtin drivers get wrong
+    //     (gl_NumSubgroups) with the value the rest of the topology implies.
+    // The 32-lane shared-memory emulation (EmulateSubgroupsPass) is a LAST RESORT for
+    // devices with no subgroup support at all, and only when the user opts in with
+    // MOBILEGL_MAGMA_EMULATE_SUBGROUP=1; it never replaces available native operations.
+
+    inline constexpr Uint32 kEmulatedSubgroupSize = 32u;
+    inline constexpr Uint32 kEmulatedSubgroupStages = GL_COMPUTE_SHADER_BIT;
+    inline constexpr Uint32 kEmulatedSubgroupFeatures =
+        GL_SUBGROUP_FEATURE_BASIC_BIT_KHR | GL_SUBGROUP_FEATURE_VOTE_BIT_KHR |
+        GL_SUBGROUP_FEATURE_ARITHMETIC_BIT_KHR | GL_SUBGROUP_FEATURE_BALLOT_BIT_KHR |
+        GL_SUBGROUP_FEATURE_SHUFFLE_BIT_KHR | GL_SUBGROUP_FEATURE_SHUFFLE_RELATIVE_BIT_KHR |
+        GL_SUBGROUP_FEATURE_CLUSTERED_BIT_KHR | GL_SUBGROUP_FEATURE_QUAD_BIT_KHR;
+
+    inline Bool ShouldEmulateSubgroups(const Bool nativeSubgroupSupported) {
+        return MG_Config::Features.MagmaEmulateSubgroup && !nativeSubgroupSupported &&
+               !MG_Config::Features.DisableSubgroup;
+    }
+
+    inline Bool ShouldFixIterationRPSubgroupScratch() {
+        // Auto is ON: the patch is fingerprint-gated to iterationRP's reduction and
+        // grows one under-declared array; every other module passes through untouched.
+        return MG_Config::Features.FixIterationRPSubgroupScratch !=
+               MG_Config::QuirkOverride::ForceOff;
+    }
+
+    inline Bool ShouldFixIterationRPBarrier() {
+        return MG_Config::Features.IterationRPFixBarrier;
+    }
+
+    inline Bool ShouldDeriveNumSubgroups() {
+        // Auto is ON: gl_NumSubgroups must agree with the gl_SubgroupID range for the GL
+        // contract to hold, and the derived ceil() value is the one the renderer can pin
+        // with REQUIRE_FULL_SUBGROUPS - the driver builtin is the value with no
+        // cross-driver guarantee (Adreno returns 1 for an 8-subgroup dispatch).
+        return MG_Config::Features.DeriveNumSubgroups != MG_Config::QuirkOverride::ForceOff;
+    }
+} // namespace MobileGL::MG_Backend::DirectVulkan

MobileGL/MG_Backend/DirectVulkan/VkIncludes.h

@@ -74,6 +74,18 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 // The context line (__VA_ARGS__ = its own format string + args) must be a SEPARATE log
 // call: appending its format to the base format while its arguments precede the base
 // arguments makes every conversion read the wrong slot (a %s pulling an int crashes).
+//
+// MGLOG_F and deliberately NOT latched. VK_VERIFY is the invariant-check macro: a Vulkan call
+// MobileGL believes it has already made legal came back non-success, which is a
+// should-never-happen state, not an expected failure mode a user hits. Those fast-fail loudly
+// and keep saying so - the log-quietness rules that latch W/E cover expected failures (driver
+// capability gaps, app misuse), not broken internal invariants. MOBILEGL_ASSERT below traps in
+// a DEBUG build; MGLOG_F is what makes the same condition visible in an INFO test run, where
+// the assert is compiled out by contract.
+//
+// A soft, recoverable failure must therefore NOT be routed through VK_VERIFY. Check the
+// VkResult directly and report it with MGLOG_E_ONCE - see VkTextureManager::SyncTextureResource,
+// where a driver legitimately refuses an image the format pre-check accepted.
 #define VK_VERIFY(expr, ...)                                                                                           \
     do {                                                                                                               \
         VkResult _vk_verify_result = (expr);                                                                           \

MobileGL/MG_Benchmark/CMakeLists.txt

@@ -44,3 +44,5 @@ add_subdirectory(Program)
 add_subdirectory(Buffer)
 add_subdirectory(Driver)
 add_subdirectory(Container)
+add_subdirectory(ShaderCache)
+add_subdirectory(Transpile)

MobileGL/MG_Benchmark/ShaderCache/CMakeLists.txt

@@ -0,0 +1,21 @@
+cmake_minimum_required(VERSION 3.24)
+
+add_executable(
+        TranslationCacheBench
+        TranslationCacheBench.cpp
+)
+
+target_include_directories(TranslationCacheBench PRIVATE
+        ${MGL_ROOT}/include
+        ${MGL_ROOT}/MobileGL
+        ${MGL_ROOT}/3rdparty/SPIRV-Reflect
+)
+
+target_link_libraries(
+        TranslationCacheBench PRIVATE
+        benchmark::benchmark
+        ${LINK_LIBRARIES}
+)
+
+add_test(NAME TranslationCacheBench COMMAND TranslationCacheBench --benchmark_counters_tabular=true)
+set_tests_properties(TranslationCacheBench PROPERTIES LABELS benchmark)

MobileGL/MG_Benchmark/ShaderCache/TranslationCacheBench.cpp

@@ -0,0 +1,457 @@
+// MobileGL - MobileGL/MG_Benchmark/ShaderCache/TranslationCacheBench.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// What the two-level shader translation memo is worth, measured on the workload that
+// motivated it: the KHR-GL33.texture_swizzle.smoke_* shape, where one case builds 2592
+// programs out of a handful of distinct sources.
+//
+// Four pairs of cases, each Off/On:
+//
+//   ProgramLink      - the whole glCompileShader + glLinkProgram path for one program, with
+//                      FRESH SHADER OBJECTS every iteration. This is the CTS shape exactly,
+//                      and it is the headline case now. It used to be the PESSIMISTIC one:
+//                      a hit still paid for both glslang parses, because the parse happens
+//                      at glCompileShader - a different entry point from the one L1
+//                      memoizes - and fresh shader objects meant ShaderCompileAdoptionMap
+//                      could not hand the earlier parse over either. L1c is what closed
+//                      that: the compile half of the memo recognises each stage's source
+//                      and publishes its verdict without parsing, so on a hit this case now
+//                      constructs no glslang object at all.
+//
+//   SharedShaderLink - the same program population with the shader objects KEPT ALIVE, so
+//                      the parses happen once outside the measured loop whatever the cache
+//                      does. That makes it the CONTROL for L1c rather than a target: its
+//                      numbers should not move, and if they do, L1c has added cost to a
+//                      path it was supposed to leave alone.
+//
+//   DeferredParseLink - the shape where L1c could LOSE: a constant vertex source (which
+//                      hits L1c and therefore skips its parse) against a fresh fragment
+//                      source every iteration (which makes the PROGRAM key miss, so the
+//                      skipped parse has to happen inside the link after all). Same parse
+//                      count either way, so the pair should land within noise; see its own
+//                      header below.
+//
+//   EsslTranspile    - the DirectGLES backend segment: the SPIR-V pass chain plus
+//                      SPIRV-Cross. Runs the driver-INDEPENDENT half of the real chain (the
+//                      passes SyncToBackend runs unconditionally, plus the two stage-gated
+//                      ones a fragment module reaches) so the miss path costs what
+//                      production costs; the capability-gated passes need a live ES driver
+//                      and are not reachable from a benchmark process.
+//
+// Every On case runs with a warm cache: the first iteration misses and every one after it
+// hits, which is exactly the steady state of a 2592-program smoke case.
+
+#include <benchmark/benchmark.h>
+
+#include <string>
+
+#include "Config.h"
+#include "Includes.h"
+#include "Init.h"
+#include "MG_Impl/GLImpl/Program/GL_Program.h"
+#include "MG_State/GLState/Core.h"
+#include "MG_State/GLState/ProgramState/ProgramTranslationCache.h"
+#include "MG_Util/ShaderTranspiler/ShaderCompiler.h"
+#include "MG_Util/ShaderTranspiler/SpvcSession.h"
+#include "MG_Util/ShaderTranspiler/TranslationCache.h"
+#include "MG_Util/ShaderTranspiler/Types.h"
+
+using namespace MobileGL;
+using namespace MobileGL::MG_Util::ShaderTranspiler;
+
+namespace {
+    const char* kVertexSource = R"(#version 460
+layout(location = 0) in vec3 aPos;
+out vec3 vPos;
+out vec2 vUv;
+void main() {
+    vPos = aPos;
+    vUv = aPos.xy * 0.5 + 0.5;
+    gl_Position = vec4(aPos, 1.0);
+}
+)";
+
+    // Shaped after gl3cTextureSwizzleTests.cpp's template: a sampler of one type, one
+    // TEXTURE_ACCESS, one CHANNEL, and an output whose BASIC_TYPE is the only thing that
+    // varies within a case. Padded with enough real arithmetic that the translation chain
+    // is doing work rather than measuring fixed overheads.
+    // `padLines` = 0 is the honest CTS size: gl3cTextureSwizzleTests' smoke template is a
+    // handful of lines, and that is the workload the memo exists for. The padded variant is
+    // kept alongside it because a shaderpack stage is orders of magnitude bigger, and the
+    // two bracket the ratio the cache is worth in practice.
+    String SwizzleLikeFragment(const String& prefix, const int padLines) {
+        String source = "#version 460\n";
+        source += "in vec3 vPos;\n";
+        source += "in vec2 vUv;\n";
+        source += "layout(location = 0) out " + prefix + "vec4 fragColor;\n";
+        source += "uniform sampler2D uTex;\n";
+        source += "uniform vec4 uTint;\n";
+        source += "uniform mat4 uModel;\n";
+        source += "uniform float uArr[8];\n";
+        source += "void main() {\n";
+        source += "    vec4 s = texture(uTex, vUv);\n";
+        source += "    float acc = s.r;\n";
+        for (int i = 0; i < padLines; ++i) {
+            source += "    acc = acc * 1.0001 + sin(acc + " + std::to_string(i) + ".0) * cos(acc);\n";
+        }
+        source += "    for (int i = 0; i < 8; ++i) acc += uArr[i];\n";
+        source += "    vec4 p = uModel * vec4(vPos, 1.0);\n";
+        source += "    fragColor = " + prefix + "vec4((s + uTint) * acc + p);\n";
+        source += "}\n";
+        return source;
+    }
+
+    class CacheModeScope {
+    public:
+        explicit CacheModeScope(const Bool enabled)
+            : m_saved(MG_Config::Features.ShaderTranslationCache) {
+            MG_Config::Features.ShaderTranslationCache =
+                enabled ? MG_Config::QuirkOverride::ForceOn : MG_Config::QuirkOverride::ForceOff;
+        }
+        ~CacheModeScope() { MG_Config::Features.ShaderTranslationCache = m_saved; }
+
+    private:
+        const MG_Config::QuirkOverride m_saved;
+    };
+
+    class SyncCompileScope {
+    public:
+        SyncCompileScope() : m_saved(MG_Config::Features.AsyncShaderCompile) {
+            MG_Config::Features.AsyncShaderCompile = MG_Config::QuirkOverride::ForceOff;
+        }
+        ~SyncCompileScope() { MG_Config::Features.AsyncShaderCompile = m_saved; }
+
+    private:
+        const MG_Config::QuirkOverride m_saved;
+    };
+
+    // One program, built the way the CTS builds one: fresh shader objects every time.
+    void LinkOneProgram(const String& vertexSource, const String& fragmentSource) {
+        using namespace MG_Impl::GLImpl;
+        const GLuint vs = CreateShader(GL_VERTEX_SHADER);
+        const char* vsText = vertexSource.c_str();
+        ShaderSource(vs, 1, &vsText, nullptr);
+        CompileShader(vs);
+
+        const GLuint fs = CreateShader(GL_FRAGMENT_SHADER);
+        const char* fsText = fragmentSource.c_str();
+        ShaderSource(fs, 1, &fsText, nullptr);
+        CompileShader(fs);
+
+        const GLuint program = CreateProgram();
+        AttachShader(program, vs);
+        AttachShader(program, fs);
+        LinkProgram(program);
+        benchmark::DoNotOptimize(program);
+
+        DeleteProgram(program);
+        DeleteShader(vs);
+        DeleteShader(fs);
+    }
+
+    Vector<Uint32> BuildSanitizedFragmentSpirv(const String& fragmentSource) {
+        ShaderAttrib attrib{.shaderType = GL_FRAGMENT_SHADER, .sourceStr = fragmentSource};
+        auto shader = ShaderCompiler::CompileShader(attrib);
+        if (!shader) return {};
+        ProgramAttrib programAttrib{.shaders = {shader.value()}};
+        auto program = ShaderCompiler::LinkProgram(programAttrib);
+        if (!program) return {};
+        ProgramBinaryAttrib binaryAttrib{.shaderTypes = {GL_FRAGMENT_SHADER}, .program = *program.value()};
+        auto binary = ShaderCompiler::GetSpirvBinaryFromProgram(binaryAttrib);
+        if (!binary || binary->empty()) return {};
+        Vector<Uint32> sanitized;
+        if (!ShaderCompiler::SanitizeAndOptimizeBinary(binary->front(), sanitized)) return {};
+        return sanitized;
+    }
+
+    // The driver-independent part of BackendProgramObjectImpl::TranspileSpirvToEssl, in the
+    // same order. What is missing is only the capability-gated passes (viewport lowering,
+    // multisample clamping, noperspective emulation, the image-format bake), which cannot
+    // fire without a live ES driver to arm them.
+    Bool TranspileLikeDirectGles(const Vector<Uint32>& spirv, const Uint esslVersion, String& outEssl) {
+        Vector<Uint32> a;
+        const Vector<Uint32>* effective = &spirv;
+        if (ShaderCompiler::StripUboMemberRelaxedPrecisionForEssl(*effective, a, false) && !a.empty()) {
+            effective = &a;
+        }
+        Vector<Uint32> b;
+        if (ShaderCompiler::LowerRectImages(*effective, b, false) && !b.empty()) effective = &b;
+        Vector<Uint32> c;
+        if (ShaderCompiler::Lower1DArrayImagesForEssl(*effective, c, false) && !c.empty()) effective = &c;
+        Vector<Uint32> d;
+        if (ShaderCompiler::LegalizeFragmentOutputIndexingForEssl(*effective, d, false) && !d.empty()) {
+            effective = &d;
+        }
+
+        SpvcSession session(*effective, SessionUsageBit::Transpile);
+        spvc_compiler_options options;
+        if (session.CreateOptions(&options) != SPVC_SUCCESS) return false;
+        spvc_compiler_options_set_uint(options, SPVC_COMPILER_OPTION_GLSL_VERSION, esslVersion);
+        spvc_compiler_options_set_bool(options, SPVC_COMPILER_OPTION_GLSL_ES, SPVC_TRUE);
+        spvc_compiler_options_set_bool(options, SPVC_COMPILER_OPTION_GLSL_VULKAN_SEMANTICS, SPVC_FALSE);
+        session.SetOptions(options);
+        const char* result = nullptr;
+        session.Compile(&result);
+        if (!result) return false;
+        outEssl = result;
+        return true;
+    }
+
+    EsslTranslationKeyInputs EsslInputsFor(const Vector<Uint32>& spirv) {
+        EsslTranslationKeyInputs inputs;
+        inputs.spirv = &spirv;
+        inputs.shaderType = GL_FRAGMENT_SHADER;
+        inputs.maxColorTextureSamples = 4;
+        inputs.maxIntegerSamples = 1;
+        inputs.maxDepthTextureSamples = 4;
+        inputs.advertisedMaxSamples = 4;
+        inputs.esslVersion = 320;
+        return inputs;
+    }
+} // namespace
+
+// ---------------------------------------------------------------------------------------
+// L1, in situ: the full glCompileShader + glLinkProgram path for a repeated program.
+// ---------------------------------------------------------------------------------------
+// Arg(0) = the CTS smoke size; Arg(120) = a heavy stage, bracketing the ratio.
+static void BM_ProgramLink_CacheOff(benchmark::State& state) {
+    MobileGL::Initialize();
+    const SyncCompileScope sync;
+    const CacheModeScope cache(false);
+    const String vs = kVertexSource;
+    const String fs = SwizzleLikeFragment("", static_cast<int>(state.range(0)));
+    for (auto _ : state) {
+        LinkOneProgram(vs, fs);
+    }
+    state.SetLabel("MOBILEGL_SHADER_CACHE=0");
+}
+BENCHMARK(BM_ProgramLink_CacheOff)->Arg(0)->Arg(120)->Unit(benchmark::kMicrosecond);
+
+static void BM_ProgramLink_CacheOn(benchmark::State& state) {
+    MobileGL::Initialize();
+    const SyncCompileScope sync;
+    const CacheModeScope cache(true);
+    const String vs = kVertexSource;
+    const String fs = SwizzleLikeFragment("", static_cast<int>(state.range(0)));
+    LinkOneProgram(vs, fs); // prime, so the measured loop is the steady state
+    const TranslationCacheStats before = MG_State::GLState::GetProgramTranslationCache().Stats();
+    const TranslationCacheStats parseBefore = GetShaderParseVerdictCache().Stats();
+    for (auto _ : state) {
+        LinkOneProgram(vs, fs);
+    }
+    const TranslationCacheStats stats = MG_State::GLState::GetProgramTranslationCache().Stats();
+    const TranslationCacheStats parseStats = GetShaderParseVerdictCache().Stats();
+    state.counters["L1_hits"] = static_cast<double>(stats.hits - before.hits);
+    state.counters["L1_misses"] = static_cast<double>(stats.misses - before.misses);
+    // Two stages per iteration, so a clean run shows L1c_hits == 2 * iterations and zero
+    // misses: every glCompileShader in the loop skipped its parse.
+    state.counters["L1c_hits"] = static_cast<double>(parseStats.hits - parseBefore.hits);
+    state.counters["L1c_misses"] = static_cast<double>(parseStats.misses - parseBefore.misses);
+}
+BENCHMARK(BM_ProgramLink_CacheOn)->Arg(0)->Arg(120)->Unit(benchmark::kMicrosecond);
+
+// ---------------------------------------------------------------------------------------
+// L1, the shape the memo actually exists for: MANY PROGRAMS OUT OF THE SAME SHADERS.
+//
+// The pair above deletes its shader objects every iteration, which forces a fresh glslang
+// parse per iteration no matter what the link does - glCompileShader parses, and that is a
+// DIFFERENT entry point from the one L1 memoizes. It is a real workload (what an application
+// that never reuses a shader object pays) but it is the pessimistic one, and the residual it
+// leaves is the parse, not the link.
+//
+// This pair keeps the shader objects alive, so the parses happen once before the measured
+// loop and the L1 hit then skips the link, mapIO, the SPIR-V, the reflection and the routing
+// outright.
+//
+// SINCE L1c THIS IS THE CONTROL, NOT THE TARGET. Nothing inside the measured loop calls
+// glCompileShader, so L1c cannot fire here at all - which is exactly what makes the pair
+// useful: it is the shape that says whether the compile-side memo has slowed the LINK path
+// down. Its numbers should be indistinguishable from the pre-L1c ones.
+// ---------------------------------------------------------------------------------------
+namespace {
+    struct SharedShaders {
+        GLuint vs = 0;
+        GLuint fs = 0;
+    };
+
+    SharedShaders MakeSharedShaders(const String& vertexSource, const String& fragmentSource) {
+        using namespace MG_Impl::GLImpl;
+        SharedShaders shaders;
+        shaders.vs = CreateShader(GL_VERTEX_SHADER);
+        const char* vsText = vertexSource.c_str();
+        ShaderSource(shaders.vs, 1, &vsText, nullptr);
+        CompileShader(shaders.vs);
+        shaders.fs = CreateShader(GL_FRAGMENT_SHADER);
+        const char* fsText = fragmentSource.c_str();
+        ShaderSource(shaders.fs, 1, &fsText, nullptr);
+        CompileShader(shaders.fs);
+        return shaders;
+    }
+
+    void LinkFromSharedShaders(const SharedShaders& shaders) {
+        using namespace MG_Impl::GLImpl;
+        const GLuint program = CreateProgram();
+        AttachShader(program, shaders.vs);
+        AttachShader(program, shaders.fs);
+        LinkProgram(program);
+        benchmark::DoNotOptimize(program);
+        DeleteProgram(program);
+    }
+} // namespace
+
+static void BM_SharedShaderLink_CacheOff(benchmark::State& state) {
+    MobileGL::Initialize();
+    const SyncCompileScope sync;
+    const CacheModeScope cache(false);
+    const SharedShaders shaders =
+        MakeSharedShaders(kVertexSource, SwizzleLikeFragment("", static_cast<int>(state.range(0))));
+    for (auto _ : state) {
+        LinkFromSharedShaders(shaders);
+    }
+    state.SetLabel("MOBILEGL_SHADER_CACHE=0");
+}
+BENCHMARK(BM_SharedShaderLink_CacheOff)->Arg(0)->Arg(120)->Unit(benchmark::kMicrosecond);
+
+static void BM_SharedShaderLink_CacheOn(benchmark::State& state) {
+    MobileGL::Initialize();
+    const SyncCompileScope sync;
+    const CacheModeScope cache(true);
+    const SharedShaders shaders =
+        MakeSharedShaders(kVertexSource, SwizzleLikeFragment("", static_cast<int>(state.range(0))));
+    LinkFromSharedShaders(shaders); // prime, so the measured loop is the steady state
+    const TranslationCacheStats before = MG_State::GLState::GetProgramTranslationCache().Stats();
+    for (auto _ : state) {
+        LinkFromSharedShaders(shaders);
+    }
+    const TranslationCacheStats stats = MG_State::GLState::GetProgramTranslationCache().Stats();
+    state.counters["L1_hits"] = static_cast<double>(stats.hits - before.hits);
+    state.counters["L1_misses"] = static_cast<double>(stats.misses - before.misses);
+}
+BENCHMARK(BM_SharedShaderLink_CacheOn)->Arg(0)->Arg(120)->Unit(benchmark::kMicrosecond);
+
+// ---------------------------------------------------------------------------------------
+// L2, component: the DirectGLES SPIR-V pass chain plus SPIRV-Cross for one stage.
+// ---------------------------------------------------------------------------------------
+static void BM_EsslTranspile_CacheOff(benchmark::State& state) {
+    MobileGL::Initialize();
+    const Vector<Uint32> spirv =
+        BuildSanitizedFragmentSpirv(SwizzleLikeFragment("", static_cast<int>(state.range(0))));
+    if (spirv.empty()) {
+        state.SkipWithError("could not build the fragment module");
+        return;
+    }
+    String essl;
+    for (auto _ : state) {
+        if (!TranspileLikeDirectGles(spirv, 320, essl)) {
+            state.SkipWithError("transpile failed");
+            break;
+        }
+        benchmark::DoNotOptimize(essl.data());
+    }
+    state.SetLabel("MOBILEGL_SHADER_CACHE=0");
+}
+BENCHMARK(BM_EsslTranspile_CacheOff)->Arg(0)->Arg(120)->Unit(benchmark::kMicrosecond);
+
+static void BM_EsslTranspile_CacheOn(benchmark::State& state) {
+    MobileGL::Initialize();
+    const Vector<Uint32> spirv =
+        BuildSanitizedFragmentSpirv(SwizzleLikeFragment("", static_cast<int>(state.range(0))));
+    if (spirv.empty()) {
+        state.SkipWithError("could not build the fragment module");
+        return;
+    }
+    BoundedTranslationCache<EsslTranslationResult> cache("bench L2", 64, 8u << 20);
+    const EsslTranslationKeyInputs inputs = EsslInputsFor(spirv);
+    for (auto _ : state) {
+        const TranslationCacheKey key = BuildEsslTranslationKey(inputs);
+        EsslTranslationResultPtr hit = cache.Find(key);
+        if (!hit) {
+            auto payload = MakeShared<EsslTranslationResult>();
+            if (!TranspileLikeDirectGles(spirv, inputs.esslVersion, payload->essl)) {
+                state.SkipWithError("transpile failed");
+                break;
+            }
+            cache.Insert(key, EsslTranslationResultPtr(payload), EsslTranslationResultBytes(*payload));
+            hit = payload;
+        }
+        benchmark::DoNotOptimize(hit->essl.data());
+    }
+    const TranslationCacheStats stats = cache.Stats();
+    state.counters["L2_hits"] = static_cast<double>(stats.hits);
+    state.counters["L2_misses"] = static_cast<double>(stats.misses);
+}
+BENCHMARK(BM_EsslTranspile_CacheOn)->Arg(0)->Arg(120)->Unit(benchmark::kMicrosecond);
+
+// ---------------------------------------------------------------------------------------
+// L1c, the shape where it could LOSE rather than win: the DEFERRED PARSE.
+// ---------------------------------------------------------------------------------------
+// A stage whose compile hits L1c holds no AST, so if the program-level key then MISSES, the
+// parse it skipped has to happen anyway - inside the link, via ClaimParsedShader. The parse
+// is moved, not removed, and this pair is what says whether moving it costs anything.
+//
+// The shape forces exactly that, every iteration: one CONSTANT vertex source (hits L1c after
+// the first iteration) linked against a FRESH fragment source each time (misses L1c, and
+// makes the program key miss too). So:
+//
+//   cache off - two parses at glCompileShader, then the link.
+//   cache on  - one parse at glCompileShader (the fragment), one deferred parse inside the
+//               link (the vertex), then the link.
+//
+// The parse count is identical, so these two should land within noise of each other. If the
+// On arm is materially SLOWER, L1c is charging for something - the per-compile key build and
+// hash over the full preprocessed source, or the loss of the claim-CAS reuse - and that cost
+// shows up here and nowhere else.
+//
+// The distinct fragment sources also churn both front-end levels through their FIFO caps,
+// which is the eviction behaviour a real shaderpack load produces; over a long run the
+// constant vertex entry is occasionally evicted by that churn and re-inserted, so the L1c
+// hit rate reported below is high but not exactly 1.0 per iteration.
+namespace {
+    String UniqueFragmentSource(const Uint64 serial, const int padLines) {
+        return SwizzleLikeFragment("", padLines) +
+               "\n// unique-" + std::to_string(serial) + "\n";
+    }
+} // namespace
+
+static void BM_DeferredParseLink_CacheOff(benchmark::State& state) {
+    MobileGL::Initialize();
+    const SyncCompileScope sync;
+    const CacheModeScope cache(false);
+    const String vs = kVertexSource;
+    Uint64 serial = 0;
+    for (auto _ : state) {
+        LinkOneProgram(vs, UniqueFragmentSource(serial++, static_cast<int>(state.range(0))));
+    }
+    state.SetLabel("MOBILEGL_SHADER_CACHE=0");
+}
+BENCHMARK(BM_DeferredParseLink_CacheOff)->Arg(0)->Arg(120)->Unit(benchmark::kMicrosecond);
+
+static void BM_DeferredParseLink_CacheOn(benchmark::State& state) {
+    MobileGL::Initialize();
+    const SyncCompileScope sync;
+    const CacheModeScope cache(true);
+    const String vs = kVertexSource;
+    Uint64 serial = 0;
+    LinkOneProgram(vs, UniqueFragmentSource(~0ull, static_cast<int>(state.range(0)))); // prime the vertex entry
+    const TranslationCacheStats before = MG_State::GLState::GetProgramTranslationCache().Stats();
+    const TranslationCacheStats parseBefore = GetShaderParseVerdictCache().Stats();
+    for (auto _ : state) {
+        LinkOneProgram(vs, UniqueFragmentSource(serial++, static_cast<int>(state.range(0))));
+    }
+    const TranslationCacheStats stats = MG_State::GLState::GetProgramTranslationCache().Stats();
+    const TranslationCacheStats parseStats = GetShaderParseVerdictCache().Stats();
+    // Expected shape: L1 all misses (every program is new), L1c one hit (vertex) and one miss
+    // (fragment) per iteration.
+    state.counters["L1_hits"] = static_cast<double>(stats.hits - before.hits);
+    state.counters["L1_misses"] = static_cast<double>(stats.misses - before.misses);
+    state.counters["L1c_hits"] = static_cast<double>(parseStats.hits - parseBefore.hits);
+    state.counters["L1c_misses"] = static_cast<double>(parseStats.misses - parseBefore.misses);
+}
+BENCHMARK(BM_DeferredParseLink_CacheOn)->Arg(0)->Arg(120)->Unit(benchmark::kMicrosecond);
+
+BENCHMARK_MAIN();

MobileGL/MG_Benchmark/Transpile/CMakeLists.txt

@@ -0,0 +1,20 @@
+cmake_minimum_required(VERSION 3.24)
+
+# Deliberately NOT a google-benchmark target: the interesting quantity is a per-stage
+# breakdown of one program build, which needs its own clock around sub-steps that share
+# set-up, and a plain main() keeps the output a table this can be read straight out of.
+add_executable(
+        TranspileProfile
+        TranspileProfile.cpp
+)
+
+target_include_directories(TranspileProfile PRIVATE
+        ${MGL_ROOT}/include
+        ${MGL_ROOT}/MobileGL
+        ${MGL_ROOT}/3rdparty/SPIRV-Reflect
+)
+
+target_link_libraries(
+        TranspileProfile PRIVATE
+        ${LINK_LIBRARIES}
+)

MobileGL/MG_Impl/EGLImpl/EGLImpl.cpp

@@ -21,7 +21,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
 
         EGLStateContext* GetState() {
             if (!MG_State::pEGLContext) {
-                MGLOG_E("pEGLContext is null. MG_State may not be initialized.");
+                MGLOG_E_ONCE("pEGLContext is null. MG_State may not be initialized.");
             }
             return MG_State::pEGLContext.get();
         }
@@ -146,7 +146,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
 
         auto* backendObject = GetBackendObject(state);
         if (!backendObject) {
-            MGLOG_E("activeBackendObject not initialized!");
+            MGLOG_E_ONCE("activeBackendObject not initialized!");
             state->DestroySurface(dpy, surface);
             return EGL_NO_SURFACE;
         }
@@ -172,11 +172,11 @@ namespace MobileGL::MG_Impl::EGLImpl {
 
         auto* backendObject = GetBackendObject(state);
         if (!backendObject) {
-            MGLOG_E("activeBackendObject not initialized!");
+            MGLOG_E_ONCE("activeBackendObject not initialized!");
             return EGL_FALSE;
         }
         if (!backendObject->SwapEGLBuffers(dpy, draw)) {
-            MGLOG_E("eglSwapBuffers failed on thread=%s dpy=%p draw=%p", CurrentThreadIdString().c_str(), dpy, draw);
+            MGLOG_E_ONCE("eglSwapBuffers failed on thread=%s dpy=%p draw=%p", CurrentThreadIdString().c_str(), dpy, draw);
             state->SetError(EGL_BAD_SURFACE);
             return EGL_FALSE;
         }
@@ -211,7 +211,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
 
         auto* backendObject = GetBackendObject(state);
         if (!backendObject) {
-            MGLOG_E("activeBackendObject not initialized!");
+            MGLOG_E_ONCE("activeBackendObject not initialized!");
             return EGL_FALSE;
         }
         if (!backendObject->InitializeEGLDisplay(dpy, major, minor)) {
@@ -265,7 +265,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
         if (releaseCurrentRequest) {
             if (auto* backendObject = MG_Backend::pActiveBackendObject.get()) {
                 if (!backendObject->MakeEGLCurrent(dpy, draw, read, ctx)) {
-                    MGLOG_E("eglMakeCurrent release failed in backend thread=%s", threadId.c_str());
+                    MGLOG_E_ONCE("eglMakeCurrent release failed in backend thread=%s", threadId.c_str());
                     state->MakeCurrent(oldDisplay, oldDraw, oldRead, oldContext);
                     state->SetError(EGL_BAD_ACCESS);
                     return EGL_FALSE;
@@ -277,12 +277,12 @@ namespace MobileGL::MG_Impl::EGLImpl {
 
         auto* backendObject = GetBackendObject(state);
         if (!backendObject) {
-            MGLOG_E("activeBackendObject not initialized!");
+            MGLOG_E_ONCE("activeBackendObject not initialized!");
             state->MakeCurrent(oldDisplay, oldDraw, oldRead, oldContext);
             return EGL_FALSE;
         }
         if (!backendObject->MakeEGLCurrent(dpy, draw, read, ctx)) {
-            MGLOG_E("eglMakeCurrent backend attach failed thread=%s dpy=%p draw=%p read=%p ctx=%p", threadId.c_str(),
+            MGLOG_E_ONCE("eglMakeCurrent backend attach failed thread=%s dpy=%p draw=%p read=%p ctx=%p", threadId.c_str(),
                     dpy, draw, read, ctx);
             state->SetError(EGL_BAD_ACCESS);
             state->MakeCurrent(oldDisplay, oldDraw, oldRead, oldContext);
@@ -703,7 +703,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
 
         auto* backendObject = GetBackendObject(state);
         if (!backendObject) {
-            MGLOG_E("activeBackendObject not initialized!");
+            MGLOG_E_ONCE("activeBackendObject not initialized!");
             state->DestroySurface(dpy, surface);
             return EGL_NO_SURFACE;
         }
@@ -726,7 +726,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
         }
         auto* backendObject = GetBackendObject(state);
         if (!backendObject) {
-            MGLOG_E("activeBackendObject not initialized!");
+            MGLOG_E_ONCE("activeBackendObject not initialized!");
             return EGL_FALSE;
         }
         width = std::max<EGLint>(width, 1);
@@ -764,7 +764,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
         MGLOG_D("eglGetProcAddress(%s)", name);
         void* proc = MG_Impl::GetProcAddress(name);
         if (!proc) {
-            MGLOG_W("Failed to get function: %s", name);
+            MGLOG_D("Failed to get function: %s", name);
             return nullptr;
         }
         return (__eglMustCastToProperFunctionPointerType)proc;

MobileGL/MG_Impl/GLImpl/Buffer/GL_Buffer.cpp

@@ -18,6 +18,7 @@
 #include <MG_Util/Converters/GLToStr/GLEnumConverter.h>
 #include <MG_Util/Converters/GLToMG/BufferEnumConverter.h>
 #include <MG_Util/Converters/MGToGL/BufferEnumConverter.h>
+#include <MG_Util/Texture/PixelStoreProcessor.h>
 
 namespace MobileGL::MG_Impl::GLImpl {
     namespace {
@@ -31,6 +32,8 @@ namespace MobileGL::MG_Impl::GLImpl {
             NamedBufferData,
             NamedBufferSubData,
             CopyNamedBufferSubData,
+            ClearBufferData,
+            ClearBufferSubData,
             ClearNamedBufferData,
             ClearNamedBufferSubData,
             MapBufferRange,
@@ -65,6 +68,10 @@ namespace MobileGL::MG_Impl::GLImpl {
                 return "NamedBufferSubData";
             case BufferOp::CopyNamedBufferSubData:
                 return "CopyNamedBufferSubData";
+            case BufferOp::ClearBufferData:
+                return "ClearBufferData";
+            case BufferOp::ClearBufferSubData:
+                return "ClearBufferSubData";
             case BufferOp::ClearNamedBufferData:
                 return "ClearNamedBufferData";
             case BufferOp::ClearNamedBufferSubData:
@@ -143,16 +150,6 @@ namespace MobileGL::MG_Impl::GLImpl {
                 return 0;
             }
 
-            // The pattern is replicated verbatim, which is only the whole story while the client
-            // layout already matches the internal format - the case every entry point in practice
-            // uses, and the only one the conversion machinery here can express. Say so rather than
-            // quietly writing a differently-sized pattern.
-            const SizeT sourceSize = MG_Util::GetInputBytesPerPixel(inputFormat, pixelType);
-            if (sourceSize != elementSize) {
-                MGLOG_W("%s: clear pattern is %zu bytes but internalformat 0x%X stores %zu; "
-                        "converting between them is not implemented",
-                        GetBufferOpName(op), sourceSize, internalformat, elementSize);
-            }
             return elementSize;
         }
 
@@ -194,27 +191,59 @@ namespace MobileGL::MG_Impl::GLImpl {
             return true;
         }
 
-        void ClearNamedBufferRange_State(GLuint buffer, GLenum internalformat, GLintptr offset, GLsizeiptr size,
-                                         GLenum format, GLenum type, const void* data, BufferOp op) {
+        Bool BuildClearPattern(GLenum internalformat, GLenum format, GLenum type, const void* data,
+                               SizeT patternSize, BufferOp op, Vector<Uint8>& pattern) {
+            const TextureInternalFormat internal = MG_Util::ConvertGLEnumToTextureInternalFormat(internalformat);
+            const TextureInputFormat inputFormat = MG_Util::ConvertGLEnumToTextureInputFormat(format);
+            const TexturePixelDataType inputType = MG_Util::ConvertGLEnumToTexturePixelDataType(type);
+
+            Vector<Uint8> zeroInput;
+            const void* inputPixel = data;
+            if (inputPixel == nullptr) {
+                const SizeT inputSize = MG_Util::GetInputBytesPerPixel(inputFormat, inputType);
+                if (inputSize == 0) {
+                    MG_State::pGLContext->RecordError(
+                        ErrorCode::InvalidValue,
+                        MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", GetBufferOpName(op),
+                                                     "format and type do not describe a source pixel."));
+                    return false;
+                }
+                zeroInput.resize(inputSize);
+                inputPixel = zeroInput.data();
+            }
+
+            if (!MG_Util::PixelStoreProcessor::ConvertOnePixelToInternal(
+                    internal, inputFormat, inputType, inputPixel, pattern)) {
+                MG_State::pGLContext->RecordError(
+                    ErrorCode::InvalidValue,
+                    MakeUnique<GenericErrorInfo>(
+                        "MG_Impl/GLImpl", GetBufferOpName(op),
+                        std::format("Cannot convert one ({}, {}) pixel into internalformat 0x{:X}.",
+                                    MG_Util::ConvertGLEnumToString(format), MG_Util::ConvertGLEnumToString(type),
+                                    internalformat)));
+                return false;
+            }
+
+            if (data == nullptr) {
+                // GL defines a null clear value as all zero bits in the destination store, while
+                // retaining the format/type validation above.
+                pattern.assign(patternSize, 0);
+            }
+            return true;
+        }
+
+        void ClearBufferRange_State(const SharedPtr<MG_State::GLState::BufferObject>& bufferObject,
+                                    GLenum internalformat, GLintptr offset, GLsizeiptr size,
+                                    GLenum format, GLenum type, const void* data, BufferOp op) {
             const SizeT patternSize = GetClearPatternSize(internalformat, format, type, op);
             if (patternSize == 0) return;
-
-            auto bufferObject = GetNamedBufferObject(buffer, op);
-            if (!bufferObject) return;
             if (!ValidateBufferClearRange(bufferObject, offset, size, patternSize, op)) return;
             if (size == 0) return;
 
-            Vector<Uint8> clearData(static_cast<SizeT>(size));
-            if (data) {
-                const auto* pattern = static_cast<const Uint8*>(data);
-                for (SizeT at = 0; at < clearData.size(); at += patternSize) {
-                    Memcpy(clearData.data() + at, pattern, patternSize);
-                }
-            } else {
-                Memset(clearData.data(), 0, clearData.size());
-            }
-
-            bufferObject->UploadSubData({clearData.data(), clearData.size()}, static_cast<SizeT>(offset));
+            Vector<Uint8> pattern;
+            if (!BuildClearPattern(internalformat, format, type, data, patternSize, op, pattern)) return;
+            bufferObject->FillSubData({pattern.data(), pattern.size()}, static_cast<SizeT>(offset),
+                                      static_cast<SizeT>(size));
         }
 
         auto& GetBufferBindingSlot(BufferTarget target) {
@@ -1197,17 +1226,34 @@ namespace MobileGL::MG_Impl::GLImpl {
                                         static_cast<SizeT>(writeOffset), static_cast<SizeT>(size));
     }
 
+    void ClearBufferData_State(GLenum target, GLenum internalformat, GLenum format, GLenum type, const void* data) {
+        auto bufferObject = GetBoundBufferObject(target, BufferOp::ClearBufferData);
+        if (!bufferObject) return;
+        ClearBufferRange_State(bufferObject, internalformat, 0, static_cast<GLsizeiptr>(bufferObject->GetSize()), format,
+                               type, data, BufferOp::ClearBufferData);
+    }
+
+    void ClearBufferSubData_State(GLenum target, GLenum internalformat, GLintptr offset, GLsizeiptr size,
+                                  GLenum format, GLenum type, const void* data) {
+        auto bufferObject = GetBoundBufferObject(target, BufferOp::ClearBufferSubData);
+        if (!bufferObject) return;
+        ClearBufferRange_State(bufferObject, internalformat, offset, size, format, type, data,
+                               BufferOp::ClearBufferSubData);
+    }
+
     void ClearNamedBufferData_State(GLuint buffer, GLenum internalformat, GLenum format, GLenum type, const void* data) {
         auto bufferObject = GetNamedBufferObject(buffer, BufferOp::ClearNamedBufferData);
         if (!bufferObject) return;
-        ClearNamedBufferRange_State(buffer, internalformat, 0, static_cast<GLsizeiptr>(bufferObject->GetSize()), format,
-                                    type, data, BufferOp::ClearNamedBufferData);
+        ClearBufferRange_State(bufferObject, internalformat, 0, static_cast<GLsizeiptr>(bufferObject->GetSize()), format,
+                               type, data, BufferOp::ClearNamedBufferData);
     }
 
     void ClearNamedBufferSubData_State(GLuint buffer, GLenum internalformat, GLintptr offset, GLsizeiptr size,
                                        GLenum format, GLenum type, const void* data) {
-        ClearNamedBufferRange_State(buffer, internalformat, offset, size, format, type, data,
-                                    BufferOp::ClearNamedBufferSubData);
+        auto bufferObject = GetNamedBufferObject(buffer, BufferOp::ClearNamedBufferSubData);
+        if (!bufferObject) return;
+        ClearBufferRange_State(bufferObject, internalformat, offset, size, format, type, data,
+                               BufferOp::ClearNamedBufferSubData);
     }
 
     void* MapNamedBuffer_State(GLuint buffer, GLenum access) {
@@ -1662,6 +1708,15 @@ namespace MobileGL::MG_Impl::GLImpl {
         CopyNamedBufferSubData_State(readBuffer, writeBuffer, readOffset, writeOffset, size);
     }
 
+    void ClearBufferData(GLenum target, GLenum internalformat, GLenum format, GLenum type, const void* data) {
+        ClearBufferData_State(target, internalformat, format, type, data);
+    }
+
+    void ClearBufferSubData(GLenum target, GLenum internalformat, GLintptr offset, GLsizeiptr size, GLenum format,
+                            GLenum type, const void* data) {
+        ClearBufferSubData_State(target, internalformat, offset, size, format, type, data);
+    }
+
     void ClearNamedBufferData(GLuint buffer, GLenum internalformat, GLenum format, GLenum type, const void* data) {
         ClearNamedBufferData_State(buffer, internalformat, format, type, data);
     }

MobileGL/MG_Impl/GLImpl/Buffer/GL_Buffer.h

@@ -27,6 +27,9 @@ namespace MobileGL::MG_Impl::GLImpl {
     void NamedBufferSubData(GLuint buffer, GLintptr offset, GLsizeiptr size, const void* data);
     void CopyNamedBufferSubData(GLuint readBuffer, GLuint writeBuffer, GLintptr readOffset, GLintptr writeOffset,
                                 GLsizeiptr size);
+    void ClearBufferData(GLenum target, GLenum internalformat, GLenum format, GLenum type, const void* data);
+    void ClearBufferSubData(GLenum target, GLenum internalformat, GLintptr offset, GLsizeiptr size, GLenum format,
+                            GLenum type, const void* data);
     void ClearNamedBufferData(GLuint buffer, GLenum internalformat, GLenum format, GLenum type, const void* data);
     void ClearNamedBufferSubData(GLuint buffer, GLenum internalformat, GLintptr offset, GLsizeiptr size, GLenum format,
                                  GLenum type, const void* data);

MobileGL/MG_Impl/GLImpl/Buffer/Validators.cpp

@@ -13,6 +13,7 @@
 #include <MG_Util/Converters/GLToStr/GLEnumConverter.h>
 #include <MG_Util/Converters/MGToGL/BufferEnumConverter.h>
 #include <MG_Util/Converters/MGToStr/BufferEnumConverter.h>
+#include <MG_Util/ShaderTranspiler/Types.h>
 
 namespace MobileGL::MG_Impl::GLImpl::BufferImpl {
     Bool ValidateBufferTarget(BufferTarget target) {
@@ -67,6 +68,13 @@ namespace MobileGL::MG_Impl::GLImpl::BufferImpl {
                 // binding points in GL 3.3 (no ARB_transform_feedback3).
                 pointCount = std::min<SizeT>(pointCount, 4);
             }
+            if (target == BufferTarget::AtomicCounter) {
+                // GL_MAX_ATOMIC_COUNTER_BUFFER_BINDINGS, which is NOT the state layer's array
+                // size: a counter buffer reaches a shader only as a lowered storage block, so the
+                // reserved range is the ceiling, and glGetIntegerv advertises the same number.
+                pointCount = std::min<SizeT>(
+                    pointCount, static_cast<SizeT>(MG_Util::ShaderTranspiler::MAX_ATOMIC_COUNTER_BUFFER_BINDINGS));
+            }
             return pointCount;
         }
     } // namespace

MobileGL/MG_Impl/GLImpl/Drawing/GL_Drawing.cpp

@@ -45,7 +45,11 @@ namespace MobileGL::MG_Impl::GLImpl {
         const auto& currentProgram = MG_State::pGLContext->GetProgramForDispatch();
         if (!ValidateProgramForExecution(currentProgram, functionName)) return false;
 
-        if (currentProgram->GetShaderIndexByStage(ShaderStage::Compute) < 0) {
+        // Of the EXECUTABLE, not the live attach list: attaching a compute shader to an
+        // already-linked graphics program does not give that program a compute stage to
+        // dispatch (GL 4.6 core 7.3), and letting the dispatch through on the strength of the
+        // attach hands the backend a program whose SPIR-V has no compute module in it.
+        if (!currentProgram->HasLinkedShaderStage(ShaderStage::Compute)) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidOperation,
                 MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
@@ -108,6 +112,12 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         const auto& program = MG_State::pGLContext->GetTransformFeedbackProgram();
         if (program != nullptr) {
+            // A geometry stage writes what it emits, not what the draw assembled, and the
+            // amplification factor lives in the shader. Record that this span contained such
+            // a draw so the transform feedback queries keep their backend result for it.
+            if (program->HasLinkedShaderStage(ShaderStage::Geometry)) {
+                MG_State::pGLContext->AddTransformFeedbackGeometryCaptureDraw();
+            }
             // Capacity in captured vertices = the tightest bound buffer.
             Uint64 capacityVertices = ~0ull;
             for (SizeT i = 0; i < program->GetTransformFeedbackBufferCount(); ++i) {
@@ -127,6 +137,11 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
         MG_State::pGLContext->AddTransformFeedbackPrimitives(primitives);
         MG_State::pGLContext->AddTransformFeedbackCapturedVertices(primitives * verticesPerPrimitive);
+        // Only draws that get this far are in the written counter at all. The instanced and
+        // indirect entry points never call this function, so a span that contains one is NOT
+        // fully accounted, and the queries must be able to tell: they compare this counter's
+        // delta against zero before standing in for the backend's own result.
+        MG_State::pGLContext->AddTransformFeedbackAccountedCaptureDraw();
     }
 
     // Every primitive mode a draw command accepts (GL 4.6 core table 10.1, plus
@@ -151,11 +166,23 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
     }
 
+    // The `mode` INVALID_ENUM in isolation, so a draw entry point can raise it BEFORE any of the
+    // state-dependent INVALID_OPERATIONs below. GL 4.6 core 10.4 makes a bad mode INVALID_ENUM
+    // unconditionally, while "no current program" is not even a spec-listed draw error - it is
+    // MobileGL's own null-dereference guard - so it must never shadow the enum check
+    // (KHR-GL31.api.coverage calls glDrawArraysInstanced/glDrawElementsInstanced with mode
+    // GL_POINTS-1 against a bare context and pins GL_INVALID_ENUM).
+    static Bool ValidatePrimitiveModeEnum(const char* functionName, GLenum mode) {
+        if (IsAcceptedPrimitiveMode(mode)) return true;
+
+        MG_State::pGLContext->RecordError(
+            ErrorCode::InvalidEnum,
+            MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName, "mode is not an accepted primitive type."));
+        return false;
+    }
+
     static Bool ValidatePrimitiveModeForBackend(const char* functionName, GLenum mode) {
-        if (!IsAcceptedPrimitiveMode(mode)) {
-            MG_State::pGLContext->RecordError(
-                ErrorCode::InvalidEnum,
-                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName, "mode is not an accepted primitive type."));
+        if (!ValidatePrimitiveModeEnum(functionName, mode)) {
             return false;
         }
 
@@ -176,13 +203,58 @@ namespace MobileGL::MG_Impl::GLImpl {
             return false;
         }
 
+        const auto& currentProgram = MG_State::pGLContext->GetProgramForDraw();
+
+        // GL 4.6 core 10.1: the tessellation pipeline's only input primitive is GL_PATCHES, and
+        // GL_PATCHES has no meaning without it. Both directions are INVALID_OPERATION, and
+        // neither was implemented - which is two of the four sites
+        // KHR-GL43.transform_feedback.api_errors_test checks with one shared message string.
+        // The EVALUATION stage is what decides: a control stage cannot run without one, and a
+        // program carrying only an evaluation stage still tessellates, through GL's
+        // fixed-function pass-through control stage (11.2.2).
+        // Asked of the LAST LINK, not the live attach list (GL 4.6 core 7.3): attaching a
+        // tessellation evaluation shader to an already-linked program does not put it in the
+        // executable, so reading the live list here would reject every non-GL_PATCHES draw
+        // against a program that does not tessellate - and keep rejecting them, since a detach
+        // is likewise deferred to the next link.
+        const Bool tessellationActive = currentProgram && currentProgram->HasLinkedShaderStage(ShaderStage::TessEval);
+        if (tessellationActive && mode != GL_PATCHES) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>(
+                    "MG_Impl/GLImpl", functionName,
+                    "A program with a tessellation evaluation shader can only be drawn with GL_PATCHES."));
+            return false;
+        }
+        if (!tessellationActive && mode == GL_PATCHES) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
+                                             "GL_PATCHES requires an active tessellation evaluation shader."));
+            return false;
+        }
+
         // A geometry stage only accepts the primitive types that decompose into its declared
         // input primitive (GL 4.6 core 11.3.1); anything else is INVALID_OPERATION. GL_PATCHES
         // is the tessellation pipeline's input and reaches the geometry stage already
         // converted, so it is not constrained here.
-        const auto& currentProgram = MG_State::pGLContext->GetProgramForDraw();
-        const GLenum gsInput = currentProgram ? currentProgram->GetGeometryInputType() : GL_NONE;
-        if (gsInput != GL_NONE && mode != GL_PATCHES) {
+        //
+        // "Is there a geometry stage at all" has to be asked of the STAGE, never of the input
+        // primitive: GL_NONE and GL_POINTS are both 0, so a `layout(points) in` geometry shader
+        // is indistinguishable from no geometry shader by its reflected input type alone. The
+        // sentinel test this replaces therefore skipped the whole rule for exactly the geometry
+        // shaders whose input is the most restrictive one - every mode but GL_POINTS was
+        // accepted (KHR-GL43.transform_feedback.api_errors_test draws a points-in geometry
+        // program with GL_LINES and requires INVALID_OPERATION).
+        //
+        // And it has to be asked of the LAST LINK: gsInputPrimitive is a link artifact, so
+        // pairing it with the live attach list would re-point the very same 0-aliasing rather
+        // than remove it. In the window after glAttachShader(GS) on a linked program the live
+        // list says "geometry present" while the artifact still reads GL_NONE == GL_POINTS, and
+        // the switch below would silently reject every mode but GL_POINTS.
+        const Bool geometryActive = currentProgram && currentProgram->HasLinkedShaderStage(ShaderStage::Geometry);
+        const GLenum gsInput = geometryActive ? currentProgram->GetGeometryInputType() : GL_NONE;
+        if (geometryActive && mode != GL_PATCHES) {
             Bool compatible = false;
             switch (gsInput) {
             case GL_POINTS:
@@ -216,13 +288,20 @@ namespace MobileGL::MG_Impl::GLImpl {
         // While transform feedback is active the draw's primitive type must match
         // the feedback primitive mode (GL 3.3 core 13.2.2). With a geometry shader
         // the constraint moves to the shader's output primitive type instead, so
-        // the draw mode itself is unconstrained here. A paused span is exempt: it
-        // captures nothing, so there is nothing for the mode to be incompatible with
-        // (GL 4.6 core 13.2.3).
+        // the draw mode itself is unconstrained here - and a TESSELLATION EVALUATION
+        // stage relocates it exactly the same way (GL 4.6 core 13.2.2 names both):
+        // what is captured is the tessellator's output primitive, and the draw mode
+        // can only ever be GL_PATCHES. A paused span is exempt: it captures nothing,
+        // so there is nothing for the mode to be incompatible with (GL 4.6 core 13.2.3).
+        const auto& feedbackProgram = MG_State::pGLContext->GetTransformFeedbackProgram();
+        // Both stage tests are asked of the last link, for the same reason as the two guards
+        // above: what relocates the constraint is a stage the program actually RUNS, and an
+        // attach that has not been linked in yet gives it none.
+        const Bool feedbackModeIsProgramDriven =
+            feedbackProgram && (feedbackProgram->HasLinkedShaderStage(ShaderStage::Geometry) ||
+                                feedbackProgram->HasLinkedShaderStage(ShaderStage::TessEval));
         if (MG_State::pGLContext->IsTransformFeedbackActive() &&
-            !MG_State::pGLContext->IsTransformFeedbackPaused() &&
-            !(MG_State::pGLContext->GetTransformFeedbackProgram() &&
-              MG_State::pGLContext->GetTransformFeedbackProgram()->GetShaderIndexByStage(ShaderStage::Geometry) >= 0)) {
+            !MG_State::pGLContext->IsTransformFeedbackPaused() && !feedbackModeIsProgramDriven) {
             const GLenum feedbackMode = MG_State::pGLContext->GetTransformFeedbackPrimitiveMode();
             Bool compatible = false;
             switch (feedbackMode) {
@@ -303,10 +382,23 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
     }
 
+    // GL 4.6 core 10.9: inside a conditional block whose predicate did not pass, the drawing
+    // commands, Clear, ClearBuffer* and the compute dispatches are DISCARDED. The gate sits on the
+    // wrappers that ISSUE the backend call rather than at the top of each entry point, so that
+    // everything a real driver would still do inside the block - argument validation and the
+    // errors it raises - happens exactly as it does outside one, and only the command itself is
+    // dropped. It is deliberately not on the frontend's transform-feedback accounting either:
+    // that mirrors what the capture stage would have written, and a conditional block around a
+    // capturing draw has no test coverage in either direction.
+    static Bool ConditionalRenderDiscardsCommand() {
+        return MG_State::pGLContext->ConditionalRenderDiscardsCommands();
+    }
+
     void Clear_Backend(GLbitfield mask) {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.Clear(mask);
     }
 
@@ -314,6 +406,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawElements(mode, count, type, indices);
     }
 
@@ -322,6 +415,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.MultiDrawElements(mode, count, type, indices, drawcount);
     }
 
@@ -330,6 +424,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.MultiDrawElementsBaseVertex(mode, count, type, indices, drawcount,
                                                                           basevertex);
     }
@@ -338,6 +433,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawArrays(mode, first, count);
     }
 
@@ -345,6 +441,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.MultiDrawArrays(mode, first, count, drawcount);
     }
 
@@ -353,6 +450,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawElementsBaseVertex(mode, count, type, indices, basevertex);
     }
 
@@ -361,6 +459,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.MultiDrawElementsIndirect(mode, type, indirect, drawcount, stride);
     }
 
@@ -368,6 +467,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.MultiDrawArraysIndirect(mode, indirect, drawcount, stride);
     }
 
@@ -376,6 +476,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.MultiDrawElementsIndirectCount(mode, type, indirect, drawcount,
                                                                              maxdrawcount, stride);
     }
@@ -385,6 +486,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.MultiDrawArraysIndirectCount(mode, indirect, drawcount, maxdrawcount,
                                                                            stride);
     }
@@ -394,6 +496,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawRangeElementsBaseVertex(mode, start, end, count, type, indices,
                                                                           basevertex);
     }
@@ -403,6 +506,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawRangeElements(mode, start, end, count, type, indices);
     }
 
@@ -412,6 +516,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawElementsInstancedBaseVertexBaseInstance(
             mode, count, type, indices, instancecount, basevertex, baseinstance);
     }
@@ -421,6 +526,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawElementsInstancedBaseVertex(mode, count, type, indices, instancecount,
                                                                               basevertex);
     }
@@ -430,6 +536,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawElementsInstancedBaseInstance(mode, count, type, indices,
                                                                                 instancecount, baseinstance);
     }
@@ -439,6 +546,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawElementsInstanced(mode, count, type, indices, instancecount);
     }
 
@@ -446,6 +554,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawElementsIndirect(mode, type, indirect);
     }
     void DrawArraysInstancedBaseInstance_Backend(GLenum mode, GLint first, GLsizei count, GLsizei instancecount,
@@ -453,6 +562,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawArraysInstancedBaseInstance(mode, first, count, instancecount,
                                                                               baseinstance);
     }
@@ -461,6 +571,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawArraysInstanced(mode, first, count, instancecount);
     }
 
@@ -468,6 +579,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 #ifdef TRACY_ENABLE
         ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
 #endif
+        if (ConditionalRenderDiscardsCommand()) return;
         MG_Backend::gBackendFunctionsTable.GL.DrawArraysIndirect(mode, indirect);
     }
 
@@ -496,6 +608,9 @@ namespace MobileGL::MG_Impl::GLImpl {
                 return;
             }
         }
+        // GL 4.3 added both dispatches to the conditional-render set (GL 4.6 core 10.9), which is
+        // exactly what KHR-GL43.compute_shader.conditional-dispatching checks.
+        if (ConditionalRenderDiscardsCommand()) return;
         dispatchCompute(numGroupsX, numGroupsY, numGroupsZ);
     }
 
@@ -547,6 +662,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             return;
         }
         if (!ValidateCurrentProgramForCompute(__func__)) return;
+        if (ConditionalRenderDiscardsCommand()) return;
         dispatchComputeIndirect(indirect);
     }
 
@@ -596,12 +712,14 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void MultiDrawElementsIndirect(GLenum mode, GLenum type, const void* indirect, GLsizei drawcount, GLsizei stride) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         MultiDrawElementsIndirect_Backend(mode, type, indirect, drawcount, stride);
     }
 
     void MultiDrawArraysIndirect(GLenum mode, const void* indirect, GLsizei drawcount, GLsizei stride) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         MultiDrawArraysIndirect_Backend(mode, indirect, drawcount, stride);
@@ -715,12 +833,14 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     void DrawRangeElementsBaseVertex(GLenum mode, GLuint start, GLuint end, GLsizei count, GLenum type,
                                      const void* indices, GLint basevertex) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         DrawRangeElementsBaseVertex_Backend(mode, start, end, count, type, indices, basevertex);
     }
 
     void DrawRangeElements(GLenum mode, GLuint start, GLuint end, GLsizei count, GLenum type, const void* indices) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         DrawRangeElements_Backend(mode, start, end, count, type, indices);
@@ -728,6 +848,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     void DrawElementsInstancedBaseVertexBaseInstance(GLenum mode, GLsizei count, GLenum type, const void* indices,
                                                      GLsizei instancecount, GLint basevertex, GLuint baseinstance) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         DrawElementsInstancedBaseVertexBaseInstance_Backend(mode, count, type, indices, instancecount, basevertex,
@@ -736,6 +857,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     void DrawElementsInstancedBaseVertex(GLenum mode, GLsizei count, GLenum type, const void* indices,
                                          GLsizei instancecount, GLint basevertex) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         DrawElementsInstancedBaseVertex_Backend(mode, count, type, indices, instancecount, basevertex);
@@ -743,18 +865,21 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     void DrawElementsInstancedBaseInstance(GLenum mode, GLsizei count, GLenum type, const void* indices,
                                            GLsizei instancecount, GLuint baseinstance) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         DrawElementsInstancedBaseInstance_Backend(mode, count, type, indices, instancecount, baseinstance);
     }
 
     void DrawElementsInstanced(GLenum mode, GLsizei count, GLenum type, const void* indices, GLsizei instancecount) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         DrawElementsInstanced_Backend(mode, count, type, indices, instancecount);
     }
 
     void DrawElementsIndirect(GLenum mode, GLenum type, const void* indirect) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         if (!ValidateDrawElementsIndexType(__func__, type)) return;
@@ -764,18 +889,21 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     void DrawArraysInstancedBaseInstance(GLenum mode, GLint first, GLsizei count, GLsizei instancecount,
                                          GLuint baseinstance) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         DrawArraysInstancedBaseInstance_Backend(mode, first, count, instancecount, baseinstance);
     }
 
     void DrawArraysInstanced(GLenum mode, GLint first, GLsizei count, GLsizei instancecount) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         DrawArraysInstanced_Backend(mode, first, count, instancecount);
     }
 
     void DrawArraysIndirect(GLenum mode, const void* indirect) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         if (!ValidateIndirectDrawSource(__func__, indirect, kDrawArraysIndirectCommandBytes)) return;
@@ -783,6 +911,7 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void DrawElementsBaseVertex(GLenum mode, GLsizei count, GLenum type, const void* indices, GLint basevertex) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         AccountTransformFeedbackPrimitives(mode, count);
@@ -790,6 +919,7 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void DrawArrays(GLenum mode, GLint first, GLsizei count) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         AccountTransformFeedbackPrimitives(mode, count);
@@ -797,6 +927,7 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void MultiDrawArrays(GLenum mode, const GLint* first, const GLsizei* count, GLsizei drawcount) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         if (drawcount < 0) {
@@ -810,6 +941,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     void MultiDrawElements(GLenum mode, const GLsizei* count, GLenum type, const void* const* indices,
                            GLsizei drawcount) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         MultiDrawElements_Backend(mode, count, type, indices, drawcount);
@@ -817,6 +949,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     void MultiDrawElementsBaseVertex(GLenum mode, const GLsizei* count, GLenum type, const void* const* indices,
                                      GLsizei drawcount, const GLint* basevertex) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         MultiDrawElementsBaseVertex_Backend(mode, count, type, indices, drawcount, basevertex);
@@ -827,6 +960,7 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void DrawElements(GLenum mode, GLsizei count, GLenum type, const void* indices) {
+        if (!ValidatePrimitiveModeEnum(__func__, mode)) return;
         if (!ValidateCurrentProgramForExecution(__func__)) return;
         if (!ValidatePrimitiveModeForBackend(__func__, mode)) return;
         AccountTransformFeedbackPrimitives(mode, count);

MobileGL/MG_Impl/GLImpl/Exporting/Definitions.cpp

@@ -25,12 +25,12 @@
 #define DECLARE_GL_FUNCTION_STUB_HEAD(type, name, ...) MOBILEGL_GL_API type gl##name(__VA_ARGS__) {
 
 #define DECLARE_GL_FUNCTION_STUB_END(type, name, ...)                                                                  \
-    MGLOG_W("Stub function: %s(...)", __FUNCTION__);                                                                   \
+    MGLOG_W_ONCE("Stub function: %s(...)", __FUNCTION__);                                                                   \
     return (type)1;                                                                                                    \
     }
 
 #define DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(type, name, ...)                                                        \
-    MGLOG_W("Stub function: %s(...)", __FUNCTION__);                                                                   \
+    MGLOG_W_ONCE("Stub function: %s(...)", __FUNCTION__);                                                                   \
     }
 
 #define DECLARE_GL_FUNCTION_HEAD(type, name, ...) MOBILEGL_GL_API type gl##name(__VA_ARGS__) {
@@ -725,8 +725,8 @@ DECLARE_GL_FUNCTION_STUB_HEAD(void, LoadName, GLuint name) DECLARE_GL_FUNCTION_S
 DECLARE_GL_FUNCTION_STUB_HEAD(void, PushName, GLuint name) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, PushName, name)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, PopName) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, PopName)
 DECLARE_GL_FUNCTION_HEAD(void, ClampColor, GLenum target, GLenum clamp) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ClampColor, target, clamp)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, BeginConditionalRender, GLuint id, GLenum mode) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, BeginConditionalRender, id, mode)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, EndConditionalRender, void) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, EndConditionalRender)
+DECLARE_GL_FUNCTION_HEAD(void, BeginConditionalRender, GLuint id, GLenum mode) DECLARE_GL_FUNCTION_END_NO_RETURN(void, BeginConditionalRender, id, mode)
+DECLARE_GL_FUNCTION_HEAD(void, EndConditionalRender) DECLARE_GL_FUNCTION_END_NO_RETURN(void, EndConditionalRender)
 DECLARE_GL_FUNCTION_HEAD(void, VertexAttribI1i, GLuint index, GLint x) DECLARE_GL_FUNCTION_END_NO_RETURN(void, VertexAttribI1i, index, x)
 DECLARE_GL_FUNCTION_HEAD(void, VertexAttribI2i, GLuint index, GLint x, GLint y) DECLARE_GL_FUNCTION_END_NO_RETURN(void, VertexAttribI2i, index, x, y)
 DECLARE_GL_FUNCTION_HEAD(void, VertexAttribI3i, GLuint index, GLint x, GLint y, GLint z) DECLARE_GL_FUNCTION_END_NO_RETURN(void, VertexAttribI3i, index, x, y, z)
@@ -969,24 +969,24 @@ DECLARE_GL_FUNCTION_STUB_HEAD(void, VertexAttribL3dv, GLuint index, const GLdoub
 DECLARE_GL_FUNCTION_STUB_HEAD(void, VertexAttribL4dv, GLuint index, const GLdouble* v) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, VertexAttribL4dv, index, v)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, VertexAttribLPointer, GLuint index, GLint size, GLenum type, GLsizei stride, const void* pointer) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, VertexAttribLPointer, index, size, type, stride, pointer)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, GetVertexAttribLdv, GLuint index, GLenum pname, GLdouble* params) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, GetVertexAttribLdv, index, pname, params)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, ViewportArrayv, GLuint first, GLsizei count, const GLfloat* v) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ViewportArrayv, first, count, v)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, ViewportIndexedf, GLuint index, GLfloat x, GLfloat y, GLfloat w, GLfloat h) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ViewportIndexedf, index, x, y, w, h)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, ViewportIndexedfv, GLuint index, const GLfloat* v) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ViewportIndexedfv, index, v)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, ScissorArrayv, GLuint first, GLsizei count, const GLint* v) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ScissorArrayv, first, count, v)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, ScissorIndexed, GLuint index, GLint left, GLint bottom, GLsizei width, GLsizei height) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ScissorIndexed, index, left, bottom, width, height)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, ScissorIndexedv, GLuint index, const GLint* v) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ScissorIndexedv, index, v)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, DepthRangeArrayv, GLuint first, GLsizei count, const GLdouble* v) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, DepthRangeArrayv, first, count, v)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, DepthRangeIndexed, GLuint index, GLdouble n, GLdouble f) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, DepthRangeIndexed, index, n, f)
+DECLARE_GL_FUNCTION_HEAD(void, ViewportArrayv, GLuint first, GLsizei count, const GLfloat* v) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ViewportArrayv, first, count, v)
+DECLARE_GL_FUNCTION_HEAD(void, ViewportIndexedf, GLuint index, GLfloat x, GLfloat y, GLfloat w, GLfloat h) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ViewportIndexedf, index, x, y, w, h)
+DECLARE_GL_FUNCTION_HEAD(void, ViewportIndexedfv, GLuint index, const GLfloat* v) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ViewportIndexedfv, index, v)
+DECLARE_GL_FUNCTION_HEAD(void, ScissorArrayv, GLuint first, GLsizei count, const GLint* v) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ScissorArrayv, first, count, v)
+DECLARE_GL_FUNCTION_HEAD(void, ScissorIndexed, GLuint index, GLint left, GLint bottom, GLsizei width, GLsizei height) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ScissorIndexed, index, left, bottom, width, height)
+DECLARE_GL_FUNCTION_HEAD(void, ScissorIndexedv, GLuint index, const GLint* v) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ScissorIndexedv, index, v)
+DECLARE_GL_FUNCTION_HEAD(void, DepthRangeArrayv, GLuint first, GLsizei count, const GLdouble* v) DECLARE_GL_FUNCTION_END_NO_RETURN(void, DepthRangeArrayv, first, count, v)
+DECLARE_GL_FUNCTION_HEAD(void, DepthRangeIndexed, GLuint index, GLdouble n, GLdouble f) DECLARE_GL_FUNCTION_END_NO_RETURN(void, DepthRangeIndexed, index, n, f)
 DECLARE_GL_FUNCTION_HEAD(void, GetFloati_v, GLenum target, GLuint index, GLfloat* data) DECLARE_GL_FUNCTION_END_NO_RETURN(void, GetFloati_v, target, index, data)
 DECLARE_GL_FUNCTION_HEAD(void, GetDoublei_v, GLenum target, GLuint index, GLdouble* data) DECLARE_GL_FUNCTION_END_NO_RETURN(void, GetDoublei_v, target, index, data)
 DECLARE_GL_FUNCTION_HEAD(void, DrawArraysInstancedBaseInstance, GLenum mode, GLint first, GLsizei count, GLsizei instancecount, GLuint baseinstance) DECLARE_GL_FUNCTION_END_NO_RETURN(void, DrawArraysInstancedBaseInstance, mode, first, count, instancecount, baseinstance)
 DECLARE_GL_FUNCTION_HEAD(void, DrawElementsInstancedBaseInstance, GLenum mode, GLsizei count, GLenum type, const void* indices, GLsizei instancecount, GLuint baseinstance) DECLARE_GL_FUNCTION_END_NO_RETURN(void, DrawElementsInstancedBaseInstance, mode, count, type, indices, instancecount, baseinstance)
 DECLARE_GL_FUNCTION_HEAD(void, DrawElementsInstancedBaseVertexBaseInstance, GLenum mode, GLsizei count, GLenum type, const void* indices, GLsizei instancecount, GLint basevertex, GLuint baseinstance) DECLARE_GL_FUNCTION_END_NO_RETURN(void, DrawElementsInstancedBaseVertexBaseInstance, mode, count, type, indices, instancecount, basevertex, baseinstance)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, GetActiveAtomicCounterBufferiv, GLuint program, GLuint bufferIndex, GLenum pname, GLint* params) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, GetActiveAtomicCounterBufferiv, program, bufferIndex, pname, params)
+DECLARE_GL_FUNCTION_HEAD(void, GetActiveAtomicCounterBufferiv, GLuint program, GLuint bufferIndex, GLenum pname, GLint* params) DECLARE_GL_FUNCTION_END_NO_RETURN(void, GetActiveAtomicCounterBufferiv, program, bufferIndex, pname, params)
 DECLARE_GL_FUNCTION_HEAD(void, DrawTransformFeedbackInstanced, GLenum mode, GLuint id, GLsizei instancecount) DECLARE_GL_FUNCTION_END_NO_RETURN(void, DrawTransformFeedbackInstanced, mode, id, instancecount)
 DECLARE_GL_FUNCTION_HEAD(void, DrawTransformFeedbackStreamInstanced, GLenum mode, GLuint id, GLuint stream, GLsizei instancecount) DECLARE_GL_FUNCTION_END_NO_RETURN(void, DrawTransformFeedbackStreamInstanced, mode, id, stream, instancecount)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, ClearBufferData, GLenum target, GLenum internalformat, GLenum format, GLenum type, const void* data) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ClearBufferData, target, internalformat, format, type, data)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, ClearBufferSubData, GLenum target, GLenum internalformat, GLintptr offset, GLsizeiptr size, GLenum format, GLenum type, const void* data) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ClearBufferSubData, target, internalformat, offset, size, format, type, data)
+DECLARE_GL_FUNCTION_HEAD(void, ClearBufferData, GLenum target, GLenum internalformat, GLenum format, GLenum type, const void* data) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ClearBufferData, target, internalformat, format, type, data)
+DECLARE_GL_FUNCTION_HEAD(void, ClearBufferSubData, GLenum target, GLenum internalformat, GLintptr offset, GLsizeiptr size, GLenum format, GLenum type, const void* data) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ClearBufferSubData, target, internalformat, offset, size, format, type, data)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, GetInternalformati64v, GLenum target, GLenum internalformat, GLenum pname, GLsizei count, GLint64* params) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, GetInternalformati64v, target, internalformat, pname, count, params)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, InvalidateTexSubImage, GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint zoffset, GLsizei width, GLsizei height, GLsizei depth) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, InvalidateTexSubImage, texture, level, xoffset, yoffset, zoffset, width, height, depth)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, InvalidateTexImage, GLuint texture, GLint level) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, InvalidateTexImage, texture, level)
@@ -2585,7 +2585,7 @@ DECLARE_GL_FUNCTION_STUB_HEAD(void, BindTransformFeedbackNV, GLenum target, GLui
 DECLARE_GL_FUNCTION_STUB_HEAD(void, DeleteTransformFeedbacksNV, GLsizei n, const GLuint* ids) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, DeleteTransformFeedbacksNV, n, ids)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, GenTransformFeedbacksNV, GLsizei n, GLuint* ids) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, GenTransformFeedbacksNV, n, ids)
 MOBILEGL_GL_API GLboolean glIsTransformFeedbackNV(GLuint id) {
-    MGLOG_W("Stub function: %s(...)", __FUNCTION__);
+    MGLOG_W_ONCE("Stub function: %s(...)", __FUNCTION__);
     return GL_FALSE;
 }
 DECLARE_GL_FUNCTION_STUB_HEAD(void, PauseTransformFeedbackNV, void) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, PauseTransformFeedbackNV, )
@@ -3181,5 +3181,5 @@ MOBILEGL_GL_API void glVertexAttribDivisorARB(GLuint index, GLuint divisor) {
 }
 
 MOBILEGL_GL_API void glWindowRectanglesEXT(GLenum mode, GLsizei count, const GLint* box) {
-    MGLOG_W("Stub function: %s(...)", __FUNCTION__);
+    MGLOG_W_ONCE("Stub function: %s(...)", __FUNCTION__);
 }

MobileGL/MG_Impl/GLImpl/Framebuffer/GL_Framebuffer.cpp

@@ -13,6 +13,7 @@
 #include <MG_Backend/BackendObjects.h>
 #include <MG_Util/Metrics/TextureMetrics.h>
 #include <MG_Impl/GLImpl/Texture/Validators.h>
+#include <MG_Impl/GLImpl/Getter/GL_Getter.h>
 #include <MG_State/GLState/ErrorState/Error.h>
 #include <MG_Util/Converters/GLToStr/GLEnumConverter.h>
 #include <MG_Util/Converters/GLToMG/TextureEnumConverter.h>
@@ -547,7 +548,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                                       GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter) {
         auto blitNamedFramebuffer = MG_Backend::gBackendFunctionsTable.GL.BlitNamedFramebuffer;
         if (!blitNamedFramebuffer) {
-            MGLOG_E("glBlitNamedFramebuffer skipped: backend does not implement explicit framebuffer blit.");
+            MGLOG_E_ONCE("glBlitNamedFramebuffer skipped: backend does not implement explicit framebuffer blit.");
             return;
         }
         blitNamedFramebuffer(readFramebuffer, drawFramebuffer, srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1,
@@ -558,7 +559,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                                          GLenum buffer, GLint drawbuffer, const GLfloat* value) {
         auto clearNamedFramebufferfv = MG_Backend::gBackendFunctionsTable.GL.ClearNamedFramebufferfv;
         if (!clearNamedFramebufferfv) {
-            MGLOG_E("glClearNamedFramebufferfv skipped: backend does not implement explicit framebuffer clear.");
+            MGLOG_E_ONCE("glClearNamedFramebufferfv skipped: backend does not implement explicit framebuffer clear.");
             return;
         }
         clearNamedFramebufferfv(framebuffer, buffer, drawbuffer, value);
@@ -568,7 +569,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                                          GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil) {
         auto clearNamedFramebufferfi = MG_Backend::gBackendFunctionsTable.GL.ClearNamedFramebufferfi;
         if (!clearNamedFramebufferfi) {
-            MGLOG_E("glClearNamedFramebufferfi skipped: backend does not implement explicit framebuffer clear.");
+            MGLOG_E_ONCE("glClearNamedFramebufferfi skipped: backend does not implement explicit framebuffer clear.");
             return;
         }
         clearNamedFramebufferfi(framebuffer, buffer, drawbuffer, depth, stencil);
@@ -578,7 +579,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                                          GLenum buffer, GLint drawbuffer, const GLint* value) {
         auto clearNamedFramebufferiv = MG_Backend::gBackendFunctionsTable.GL.ClearNamedFramebufferiv;
         if (!clearNamedFramebufferiv) {
-            MGLOG_E("glClearNamedFramebufferiv skipped: backend does not implement explicit framebuffer clear.");
+            MGLOG_E_ONCE("glClearNamedFramebufferiv skipped: backend does not implement explicit framebuffer clear.");
             return;
         }
         clearNamedFramebufferiv(framebuffer, buffer, drawbuffer, value);
@@ -588,7 +589,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                                           GLenum buffer, GLint drawbuffer, const GLuint* value) {
         auto clearNamedFramebufferuiv = MG_Backend::gBackendFunctionsTable.GL.ClearNamedFramebufferuiv;
         if (!clearNamedFramebufferuiv) {
-            MGLOG_E("glClearNamedFramebufferuiv skipped: backend does not implement explicit framebuffer clear.");
+            MGLOG_E_ONCE("glClearNamedFramebufferuiv skipped: backend does not implement explicit framebuffer clear.");
             return;
         }
         clearNamedFramebufferuiv(framebuffer, buffer, drawbuffer, value);
@@ -617,16 +618,17 @@ namespace MobileGL::MG_Impl::GLImpl {
         if (MG_Backend::pActiveBackendObject == nullptr) {
             return std::numeric_limits<Int>::max();
         }
-        return std::max(MG_Backend::pActiveBackendObject->GetDynamicParameters().MaxSamples, 1);
+        return GetAdvertisedMaxSamples();
     }
 
-    // GL_MAX_SAMPLES is the ceiling over all formats; an integer format has its own, lower
-    // one (GL_MAX_INTEGER_SAMPLES) and GL 4.6 core 9.2.4 makes exceeding it INVALID_OPERATION.
-    // The multisample TEXTURE path already resolves the limit per format
-    // (GL_Texture.cpp, GetMaxTextureSamplesForFormat); renderbuffers only ever compared
-    // against GL_MAX_SAMPLES, so on a driver where the two differ - Adreno reports
-    // GL_MAX_SAMPLES 4 and GL_MAX_INTEGER_SAMPLES 1 - an integer renderbuffer accepted a
-    // sample count the format cannot deliver, and said GL_NO_ERROR about it.
+    // GL_MAX_SAMPLES is the ceiling over all formats; an integer format has its own
+    // (GL_MAX_INTEGER_SAMPLES) and GL 4.6 core 9.2.4 makes exceeding it INVALID_OPERATION.
+    // The multisample TEXTURE path resolves the limit per format the same way
+    // (GL_Texture.cpp, GetMaxSupportedTextureSamples). Both are floored to the value MobileGL
+    // advertises: on a driver where the two differ - Adreno reports GL_MAX_SAMPLES 4 and
+    // GL_MAX_INTEGER_SAMPLES 1 - rejecting the advertised count here only moves the failure
+    // from the driver into MobileGL, so the frontend accepts it and the backend clamps the
+    // count it actually hands the driver.
     Int GetMaxRenderbufferSamplesForFormat_State(TextureInternalFormat format) {
         if (MG_Backend::pActiveBackendObject == nullptr) {
             return std::numeric_limits<Int>::max();
@@ -645,7 +647,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         if (!isIntegerFormat) {
             return GetMaxRenderbufferSamples_State();
         }
-        return std::max(dynamicParameters.MaxIntegerSamples, 1);
+        // Per-format still, but never below the ceiling glGetIntegerv(GL_MAX_SAMPLES) promised:
+        // the driver's raw GL_MAX_INTEGER_SAMPLES stays the *backend* limit and the backend
+        // clamps to it, while the frontend honours what it advertised.
+        return std::max(dynamicParameters.MaxIntegerSamples, GetAdvertisedMaxSamples());
     }
 
     Bool ValidateRenderbufferStorageSize_State(GLsizei width, GLsizei height, const char* caller) {
@@ -2608,18 +2613,26 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void ClearBufferfi_Backend(GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil) {
+        // GL 4.6 core 10.9 makes ClearBuffer* conditional alongside the drawing commands.
+        if (MG_State::pGLContext->ConditionalRenderDiscardsCommands()) return;
         MG_Backend::gBackendFunctionsTable.GL.ClearBufferfi(buffer, drawbuffer, depth, stencil);
     }
 
     void ClearBufferfv_Backend(GLenum buffer, GLint drawbuffer, const GLfloat* value) {
+        // GL 4.6 core 10.9 makes ClearBuffer* conditional alongside the drawing commands.
+        if (MG_State::pGLContext->ConditionalRenderDiscardsCommands()) return;
         MG_Backend::gBackendFunctionsTable.GL.ClearBufferfv(buffer, drawbuffer, value);
     }
 
     void ClearBufferuiv_Backend(GLenum buffer, GLint drawbuffer, const GLuint* value) {
+        // GL 4.6 core 10.9 makes ClearBuffer* conditional alongside the drawing commands.
+        if (MG_State::pGLContext->ConditionalRenderDiscardsCommands()) return;
         MG_Backend::gBackendFunctionsTable.GL.ClearBufferuiv(buffer, drawbuffer, value);
     }
 
     void ClearBufferiv_Backend(GLenum buffer, GLint drawbuffer, const GLint* value) {
+        // GL 4.6 core 10.9 makes ClearBuffer* conditional alongside the drawing commands.
+        if (MG_State::pGLContext->ConditionalRenderDiscardsCommands()) return;
         MG_Backend::gBackendFunctionsTable.GL.ClearBufferiv(buffer, drawbuffer, value);
     }
 
@@ -3148,15 +3161,55 @@ namespace MobileGL::MG_Impl::GLImpl {
         GetNamedFramebufferAttachmentParameteriv_State(framebuffer, attachment, pname, params);
     }
 
+    // The three argument errors GL 4.6 core 18.3.1 asks a blit for. They have to be raised here,
+    // in the backend-independent frontend: DirectGLES drains the driver's error queue around the
+    // blit on purpose (that is how the resolve fallback probes the driver), so an ES-side
+    // rejection never reaches the application and glGetError() answered GL_NO_ERROR for a call
+    // the spec requires to fail (KHR-GL30.api.coverage's glBlitFramebuffer sub-check). DirectVulkan
+    // already dropped the bad-filter and LINEAR-with-depth/stencil calls on the floor with a log
+    // line (VulkanRenderer::BlitFramebuffer), so the only thing that changes for it is that the
+    // error is now visible where the spec says it should be.
+    static Bool ValidateBlitMaskAndFilter(const char* functionName, GLbitfield mask, GLenum filter) {
+        constexpr GLbitfield kBlitMaskBits = GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT;
+        if ((mask & ~kBlitMaskBits) != 0) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidValue,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
+                                             "mask contains bits other than GL_COLOR_BUFFER_BIT, "
+                                             "GL_DEPTH_BUFFER_BIT and GL_STENCIL_BUFFER_BIT."));
+            return false;
+        }
+        if (filter != GL_NEAREST && filter != GL_LINEAR) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidEnum,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
+                                             "filter must be GL_NEAREST or GL_LINEAR."));
+            return false;
+        }
+        // Depth and stencil have no meaningful interpolation, so GL_LINEAR is rejected outright
+        // rather than downgraded - even when the mask also carries the colour bit.
+        if (filter == GL_LINEAR && (mask & (GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT)) != 0) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
+                                             "GL_LINEAR filtering is not allowed when mask includes "
+                                             "GL_DEPTH_BUFFER_BIT or GL_STENCIL_BUFFER_BIT."));
+            return false;
+        }
+        return true;
+    }
+
     void BlitNamedFramebuffer(GLuint readFramebuffer, GLuint drawFramebuffer, GLint srcX0, GLint srcY0, GLint srcX1,
                               GLint srcY1, GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask,
                               GLenum filter) {
+        if (!ValidateBlitMaskAndFilter(__func__, mask, filter)) return;
         BlitNamedFramebuffer_State(readFramebuffer, drawFramebuffer, srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1,
                                    dstY1, mask, filter);
     }
 
     void BlitFramebuffer(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, GLint dstX0, GLint dstY0, GLint dstX1,
                          GLint dstY1, GLbitfield mask, GLenum filter) {
+        if (!ValidateBlitMaskAndFilter(__func__, mask, filter)) return;
         BlitFramebuffer_Backend(srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1, dstY1, mask, filter);
     }
 

MobileGL/MG_Impl/GLImpl/Getter/GL_Getter.cpp

@@ -16,6 +16,7 @@
 #include <MG_State/GLState/ErrorState/ErrorInfo.h>
 #include <MG_Util/Converters/GLToStr/GLEnumConverter.h>
 #include <MG_Util/Converters/GLToMG/BufferEnumConverter.h>
+#include <MG_Util/Converters/GLToMG/RenderStateEnumConverter.h>
 #include <MG_Util/Converters/MGToGL/FramebufferEnumConverter.h>
 #include <MG_Util/Converters/MGToGL/ErrorCodeConverter.h>
 #include <MG_Util/Converters/MGToGL/TextureEnumConverter.h>
@@ -24,9 +25,15 @@
 #include <MG_State/GLState/FramebufferState/FramebufferObject.h>
 #include <MG_Util/Texture/TextureFormatProcessor.h>
 #include <MG_Util/Async/ShaderCompilePool.h>
+#include <MG_Util/ShaderTranspiler/Types.h>
 #include <MG_Backend/BackendObjects.h>
 
 namespace MobileGL::MG_Impl::GLImpl {
+    // Declared rather than #included from GL_RenderState.h on purpose: that header also declares
+    // a free function named BlendEquation, which would hide the ::MobileGL::BlendEquation enum
+    // this file's blend-state queries name unqualified.
+    GLboolean IsEnabledi(GLenum target, GLuint index);
+
     namespace {
         enum class IndexedBufferQueryKind {
             Binding,
@@ -40,13 +47,29 @@ namespace MobileGL::MG_Impl::GLImpl {
             }
         }
 
-        constexpr GLint kFrontendMaxComputeUniformComponents = 1024;
-        constexpr GLint kFrontendMaxComputeAtomicCounters = 8;
-        constexpr GLint kFrontendMaxComputeAtomicCounterBuffers = 8;
+        // Shared with the glslang resource table for the same reason as the atomic-counter
+        // limits below: gl_MaxComputeUniformComponents expands from BuildTBuiltInResource.
+        constexpr GLint kFrontendMaxComputeUniformComponents =
+            static_cast<GLint>(MG_Util::ShaderTranspiler::MAX_COMPUTE_UNIFORM_COMPONENTS);
+        // Every atomic-counter limit is shared with the glslang resource table
+        // (BuildTBuiltInResource) through MG_Util/ShaderTranspiler/Types.h: GL 4.6 requires
+        // glGetIntegerv and the gl_MaxAtomicCounter* built-in constants to agree, and the two
+        // used to be independent tables that disagreed on both the binding count and the buffer
+        // size. Never move one of these without the other.
+        constexpr GLint kFrontendMaxComputeAtomicCounters =
+            static_cast<GLint>(MG_Util::ShaderTranspiler::MAX_ATOMIC_COUNTERS_PER_STAGE);
+        constexpr GLint kFrontendMaxComputeAtomicCounterBuffers =
+            static_cast<GLint>(MG_Util::ShaderTranspiler::MAX_ATOMIC_COUNTER_BUFFERS_PER_STAGE);
         constexpr GLint kFrontendMaxComputeSharedMemorySize = 32768;
         constexpr GLint kFrontendMaxComputeWorkGroupInvocations = 1024;
-        constexpr GLint kFrontendMaxCombinedAtomicCounters = 8;
-        constexpr GLint kFrontendMaxFragmentAtomicCounters = 8;
+        constexpr GLint kFrontendMaxCombinedAtomicCounters =
+            static_cast<GLint>(MG_Util::ShaderTranspiler::MAX_ATOMIC_COUNTERS_PER_STAGE);
+        constexpr GLint kFrontendMaxCombinedAtomicCounterBuffers =
+            static_cast<GLint>(MG_Util::ShaderTranspiler::MAX_ATOMIC_COUNTER_BUFFERS_PER_STAGE);
+        constexpr GLint kFrontendMaxFragmentAtomicCounters =
+            static_cast<GLint>(MG_Util::ShaderTranspiler::MAX_ATOMIC_COUNTERS_PER_STAGE);
+        constexpr GLint kFrontendMaxFragmentAtomicCounterBuffers =
+            static_cast<GLint>(MG_Util::ShaderTranspiler::MAX_ATOMIC_COUNTER_BUFFERS_PER_STAGE);
         constexpr GLint kFrontendMaxGeometryAtomicCounters = 0;
         constexpr GLint kFrontendMaxTessControlAtomicCounters = 0;
         constexpr GLint kFrontendMaxTessEvaluationAtomicCounters = 0;
@@ -60,10 +83,11 @@ namespace MobileGL::MG_Impl::GLImpl {
         constexpr GLint kFrontendMaxTessControlAtomicCounterBuffers = 0;
         constexpr GLint kFrontendMaxTessEvaluationAtomicCounterBuffers = 0;
         constexpr GLint kFrontendMaxVertexAtomicCounterBuffers = 0;
-        // One atomic counter is a uint, and a buffer never has to hold more counters than the
-        // combined limit the frontend advertises. GL 4.6 table 23.63 floors this at 32 bytes.
+        // GL_MAX_ATOMIC_COUNTER_BUFFER_SIZE: the byte offset ceiling a counter may be declared
+        // at. The matching binding count is applied in GetIndexedBufferQueryPointCount, so that
+        // the getter, the indexed queries and glBindBufferBase all share one ceiling.
         constexpr GLint kFrontendMaxAtomicCounterBufferSize =
-            kFrontendMaxCombinedAtomicCounters * static_cast<GLint>(sizeof(GLuint));
+            static_cast<GLint>(MG_Util::ShaderTranspiler::MAX_ATOMIC_COUNTER_BUFFER_SIZE);
         // KHR_debug minima (GL 4.6 table 23.66); the debug entry points are stubs, but the
         // limits they advertise still have to be legal.
         constexpr GLint kFrontendMaxDebugGroupStackDepth = 64;
@@ -97,12 +121,16 @@ namespace MobileGL::MG_Impl::GLImpl {
         constexpr GLint kFrontendSubpixelBits = 4;
         constexpr GLint kFrontendMaxSamples = 4;
 
+        // The floors under GL_MAX_COMPUTE_WORK_GROUP_COUNT / _SIZE. Shared with the compile
+        // pipeline (CaptureCompileEnv floors the same driver answers at them, and
+        // BuildTBuiltInResource expands gl_MaxComputeWorkGroup* from the result), because a
+        // shader is allowed to compare the built-in constant against this query.
         constexpr GLint GetMinComputeWorkGroupCount(GLuint index) {
-            return index < 3 ? 65535 : 0;
+            return index < 3 ? static_cast<GLint>(MG_Util::ShaderTranspiler::MIN_COMPUTE_WORK_GROUP_COUNT[index]) : 0;
         }
 
         constexpr GLint GetMinComputeWorkGroupSize(GLuint index) {
-            return index < 2 ? 1024 : (index == 2 ? 64 : 0);
+            return index < 3 ? static_cast<GLint>(MG_Util::ShaderTranspiler::MIN_COMPUTE_WORK_GROUP_SIZE[index]) : 0;
         }
 
         GLint GetMaxCombinedUniformComponents(GLint maxDefaultUniformComponents, GLint maxUniformBlocks,
@@ -180,6 +208,16 @@ namespace MobileGL::MG_Impl::GLImpl {
                     MG_Backend::pActiveBackendObject->GetDynamicParameters().MaxShaderStorageBufferBindings;
                 return std::min(frontendCount, static_cast<SizeT>(std::max(backendCount, 0)));
             }
+            if (bufferTarget == BufferTarget::AtomicCounter) {
+                // The counter family's binding count is NOT the state layer's array size: a
+                // counter buffer only reaches a shader as a lowered storage block, so what an
+                // implementation can serve is the reserved range, and that number is also what
+                // glslang compiles a layout(binding = N) atomic_uint against. Clamped here so
+                // GL_MAX_ATOMIC_COUNTER_BUFFER_BINDINGS, the indexed getters' index check and
+                // glBindBufferBase's all report the same ceiling.
+                return std::min(frontendCount,
+                                static_cast<SizeT>(MG_Util::ShaderTranspiler::MAX_ATOMIC_COUNTER_BUFFER_BINDINGS));
+            }
             return frontendCount;
         }
 
@@ -207,6 +245,23 @@ namespace MobileGL::MG_Impl::GLImpl {
             return ClampBlockCountToBindingPoints(blockCount, BufferTarget::ShaderStorage);
         }
 
+        // The per-stage GL_MAX_*_SHADER_STORAGE_BLOCKS answers. Backend-derived, and NOT a
+        // constant to be "restored" - these used to return a flat 16 for vertex, geometry and
+        // both tessellation stages, which is wrong on any host that does not serve storage
+        // blocks in those stages. Zero is a legal answer: GL 4.6 table 23.64 and ES 3.2 table
+        // 21.44 both set the minimum at 0 for every graphics stage except fragment, which is
+        // why the conformance suite gates each such test on the query instead of assuming it.
+        // ARM's GLES driver reports 0 for all four (a Mali-G925 does), and advertising 16 there
+        // bought nothing: the program still failed to link inside the backend, the frontend
+        // still reported LINK_STATUS as true, and every draw with it silently rendered nothing.
+        GLint StageStorageBlockCount(Int MG_Backend::DynamicBackendParameters::*stageLimit) {
+            static const MG_Backend::DynamicBackendParameters kBackendlessDefaults{};
+            const MG_Backend::DynamicBackendParameters& parameters =
+                MG_Backend::pActiveBackendObject ? MG_Backend::pActiveBackendObject->GetDynamicParameters()
+                                                 : kBackendlessDefaults;
+            return ClampStorageBlockCount(static_cast<GLint>(parameters.*stageLimit));
+        }
+
         bool TryDecodeDrawBufferQuery(GLenum pname, SizeT& drawBufferIndex) {
             if (pname == GL_DRAW_BUFFER) {
                 drawBufferIndex = 0;
@@ -339,26 +394,70 @@ namespace MobileGL::MG_Impl::GLImpl {
             return sampler ? static_cast<GLint>(sampler->GetExternalIndex()) : 0;
         }
 
-        // The ARB_viewport_array indexed rectangles. MobileGL keeps exactly one viewport, one
-        // scissor box and one depth range, so every in-range index answers with that single
-        // value - but it has to come from the frontend state the non-indexed getters read.
-        // The generic path at the bottom of GetIntegeri_v is a raw backend passthrough that
-        // has no case for these, so routing them through it returned zeros.
+        // The ARB_viewport_array indexed rectangles. Each of these is genuinely per-viewport
+        // frontend state (RenderStateParameters::Viewports / ScissorBoxes / DepthRanges), so the
+        // indexed getters must read the indexed storage - the generic path at the bottom of
+        // GetIntegeri_v is a raw backend passthrough that has no case for them and returned
+        // zeros, and routing them to the NON-indexed getter (what this used to do) answered every
+        // index with viewport 0's value, which is what
+        // KHR-GL43.viewport_array.{viewport,scissor,depth_range}_api caught.
         Bool IsIndexedViewportQuery(GLenum target) {
             return target == GL_VIEWPORT || target == GL_SCISSOR_BOX || target == GL_DEPTH_RANGE;
         }
 
-        // ARB_viewport_array: `index` selects a viewport and MAX_VIEWPORTS bounds it.
+        // Component count of an indexed viewport-array query, so every width of getter writes the
+        // caller's whole buffer instead of just element 0 (GL 4.6 core 22.1).
+        GLsizei IndexedViewportQueryComponents(GLenum target) {
+            return target == GL_DEPTH_RANGE ? 2 : 4;
+        }
+
+        // ARB_viewport_array: `index` selects a viewport and MAX_VIEWPORTS bounds it. The bound is
+        // the frontend's own state width, which is also exactly what GL_MAX_VIEWPORTS reports -
+        // taking it from the backend caps instead would let a device limit of 1 (a Vulkan device
+        // without the multiViewport feature) make index 1 illegal even though the state exists.
         Bool ValidateViewportQueryIndex(GLuint index, const char* caller) {
-            GLint maxViewports = 0;
-            GetIntegerv(GL_MAX_VIEWPORTS, &maxViewports);
-            if (index < static_cast<GLuint>(std::max(maxViewports, 1))) return true;
+            if (index < RenderStateParameters::MAX_VIEWPORTS) return true;
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidValue,
                 MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", caller, "Viewport index is out of range."));
             return false;
         }
 
+        // The indexed viewport/scissor/depth-range state as floats, which is the widest lossless
+        // shape MobileGL stores (the viewport really is float state; the scissor box is integral
+        // and well inside float's exact range, and every depth range is in [0, 1]). Every indexed
+        // getter width funnels through this so they can never disagree with each other.
+        void ReadIndexedViewportStateFloat(GLenum target, GLuint index, GLfloat* out) {
+            switch (target) {
+            case GL_VIEWPORT: {
+                const FloatVec4& viewport = MG_State::pGLContext->GetViewportIndexed(index);
+                out[0] = viewport.x();
+                out[1] = viewport.y();
+                out[2] = viewport.z();
+                out[3] = viewport.w();
+                return;
+            }
+            case GL_SCISSOR_BOX: {
+                const IntVec4& box = MG_State::pGLContext->GetScissorBoxIndexed(index);
+                out[0] = static_cast<GLfloat>(box.x());
+                out[1] = static_cast<GLfloat>(box.y());
+                out[2] = static_cast<GLfloat>(box.z());
+                out[3] = static_cast<GLfloat>(box.w());
+                return;
+            }
+            case GL_DEPTH_RANGE: {
+                const FloatVec2& range = MG_State::pGLContext->GetDepthRangeIndexed(index);
+                out[0] = range.x();
+                out[1] = range.y();
+                return;
+            }
+            default:
+                MOBILEGL_ASSERT(false, "ReadIndexedViewportStateFloat: unexpected target 0x%x",
+                                static_cast<Uint32>(target));
+                return;
+            }
+        }
+
         void CopyIntsToBooleans(const GLint* src, SizeT count, GLboolean* dst) {
             for (SizeT i = 0; i < count; ++i) {
                 dst[i] = src[i] ? GL_TRUE : GL_FALSE;
@@ -372,6 +471,18 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
     } // namespace
 
+    // GL 4.6 core table 23.53 requires GL_MAX_SAMPLES >= 4, so the driver's value is floored
+    // before it is advertised. Every other multisample ceiling MobileGL advertises has to be
+    // floored the same way: promising 4 samples globally while answering GL_MAX_INTEGER_SAMPLES
+    // 1 - which is exactly what Adreno reports - makes the frontend reject the very count it
+    // just told the application to use. The backends clamp the realised count instead.
+    GLint GetAdvertisedMaxSamples() {
+        if (MG_Backend::pActiveBackendObject == nullptr) {
+            return kFrontendMaxSamples;
+        }
+        return std::max(MG_Backend::pActiveBackendObject->GetDynamicParameters().MaxSamples, kFrontendMaxSamples);
+    }
+
     /* @INSERTION_POINT:FUNCTION_IMPLEMENTATION@ */
     const GLubyte* GetString(GLenum name) {
         static String vendorString;
@@ -383,7 +494,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         MGLOG_D("glGetString, name: %s", MG_Util::ConvertGLEnumToString(name).c_str());
         if (!activeBackendObject) {
-            MGLOG_E("activeBackendObject is not initialized!");
+            MGLOG_E_ONCE("activeBackendObject is not initialized!");
             return (GLubyte*)"Unknown";
         }
 
@@ -442,7 +553,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         const auto& activeBackendObject = MG_Backend::pActiveBackendObject;
         if (!activeBackendObject) {
-            MGLOG_E("activeBackendObject is not initialized!");
+            MGLOG_E_ONCE("activeBackendObject is not initialized!");
             return (GLubyte*)"Unknown";
         }
         const auto& rendererInfo = activeBackendObject->GetRendererInfo();
@@ -629,6 +740,17 @@ namespace MobileGL::MG_Impl::GLImpl {
             params[1] = dynamicParameters.ViewportBoundsRangeMax;
             return;
         }
+        // Viewport 0's rectangle, verbatim. Falling through to the integer width below would
+        // round the fractional rectangle a glViewportIndexedf(0, ...) is allowed to set, and
+        // glGetFloatv(GL_VIEWPORT) is a lossless query of float state.
+        case GL_VIEWPORT: {
+            const FloatVec4& viewport = MG_State::pGLContext->GetViewportIndexed(0);
+            params[0] = viewport.x();
+            params[1] = viewport.y();
+            params[2] = viewport.z();
+            params[3] = viewport.w();
+            return;
+        }
         case GL_MIN_FRAGMENT_INTERPOLATION_OFFSET:
         case GL_MAX_FRAGMENT_INTERPOLATION_OFFSET:
         case GL_FRAGMENT_INTERPOLATION_OFFSET_BITS: {
@@ -792,15 +914,32 @@ namespace MobileGL::MG_Impl::GLImpl {
             return;
         }
 
+        // GL 4.6 core 22.1: an indexed query answers EVERY indexed state, and GL_SCISSOR_TEST is
+        // indexed by viewport just like GL_BLEND is by draw buffer. Without this the integer
+        // width fell through to the backend passthrough and answered GL_INVALID_ENUM, which is
+        // the sticky error KHR-GL43.viewport_array.queries trips over at its next error check.
+        if (MG_Util::ConvertGLEnumToCapabilityInput(target) != CapabilityInput::Unknown) {
+            *data = IsEnabledi(target, index);
+            return;
+        }
+
         switch (target) {
         // ARB_viewport_array queries the indexed rectangles through glGetIntegeri_v as well
-        // (gl4cMultiBindTests and the viewport_array group both do). The frontend keeps one
-        // viewport and one scissor box, so every in-range index reports that one.
+        // (gl4cMultiBindTests and the viewport_array group both do).
         case GL_VIEWPORT:
         case GL_SCISSOR_BOX:
+        case GL_DEPTH_RANGE: {
             if (!ValidateViewportQueryIndex(index, __func__)) return;
-            GetIntegerv(target, data);
+            GLfloat values[4] = {};
+            ReadIndexedViewportStateFloat(target, index, values);
+            const GLsizei components = IndexedViewportQueryComponents(target);
+            for (GLsizei i = 0; i < components; ++i) {
+                // Round, not truncate: glGetIntegerv on floating-point state rounds to nearest
+                // (GL 4.6 core 22.2), so a 255.875-wide viewport reads back as 256 and not 255.
+                data[i] = static_cast<GLint>(std::lround(values[i]));
+            }
             return;
+        }
         // The vertex buffer binding points of the vertex array object that is bound. Indexed by
         // binding point, not by attribute (GL 4.6 core 10.3.1).
         case GL_VERTEX_BINDING_BUFFER:
@@ -927,7 +1066,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
         if (IsIndexedViewportQuery(target)) {
             if (!ValidateViewportQueryIndex(index, __func__)) return;
-            GetFloatv(target, data);
+            // Verbatim, NOT via the integer width: the viewport is float state and
+            // KHR-GL43.viewport_array.viewport_api compares the read-back with ==, so a
+            // glViewportIndexedf(i, 0.125f, ...) has to come back as 0.125f exactly.
+            ReadIndexedViewportStateFloat(target, index, data);
             return;
         }
         GLint ints[4] = {};
@@ -944,7 +1086,12 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
         if (IsIndexedViewportQuery(target)) {
             if (!ValidateViewportQueryIndex(index, __func__)) return;
-            GetDoublev(target, data);
+            GLfloat values[4] = {};
+            ReadIndexedViewportStateFloat(target, index, values);
+            const GLsizei components = IndexedViewportQueryComponents(target);
+            for (GLsizei i = 0; i < components; ++i) {
+                data[i] = static_cast<GLdouble>(values[i]);
+            }
             return;
         }
         GLint ints[4] = {};
@@ -1020,7 +1167,12 @@ namespace MobileGL::MG_Impl::GLImpl {
         // frontend-only value simply is not in the driver's table.
         GLint values[4] = {};
         GetIntegeri_v(target, index, values);
-        *data = static_cast<GLint64>(values[0]);
+        // The viewport-array rectangles are the only multi-component indexed state here; every
+        // other pname is scalar, so widening element 0 alone would silently truncate them.
+        const GLsizei components = IsIndexedViewportQuery(target) ? IndexedViewportQueryComponents(target) : 1;
+        for (GLsizei i = 0; i < components; ++i) {
+            data[i] = static_cast<GLint64>(values[i]);
+        }
     }
 
     void GetInteger64v(GLenum pname, GLint64* params) {
@@ -1420,15 +1572,15 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_LINE_WIDTH:
             *params = static_cast<GLint>(MG_State::pGLContext->GetLineWidth());
             return;
-        case GL_LAYER_PROVOKING_VERTEX:
-            *params = GL_LAST_VERTEX_CONVENTION;
-            return;
         case GL_LOGIC_OP_MODE:
             *params = static_cast<GLint>(MG_Util::ConvertLogicOperationToGLEnum(MG_State::pGLContext->GetLogicOp()));
             return;
         case GL_MAX_COMBINED_ATOMIC_COUNTERS:
             *params = kFrontendMaxCombinedAtomicCounters;
             return;
+        case GL_MAX_COMBINED_ATOMIC_COUNTER_BUFFERS:
+            *params = kFrontendMaxCombinedAtomicCounterBuffers;
+            return;
         case GL_MAX_COMBINED_UNIFORM_BLOCKS:
             *params = ClampUniformBlockCount(kFrontendMaxCombinedUniformBlocks);
             return;
@@ -1444,8 +1596,11 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_MAX_FRAGMENT_ATOMIC_COUNTERS:
             *params = kFrontendMaxFragmentAtomicCounters;
             return;
+        case GL_MAX_FRAGMENT_ATOMIC_COUNTER_BUFFERS:
+            *params = kFrontendMaxFragmentAtomicCounterBuffers;
+            return;
         case GL_MAX_FRAGMENT_SHADER_STORAGE_BLOCKS:
-            *params = ClampStorageBlockCount(16); // TODO
+            *params = StageStorageBlockCount(&MG_Backend::DynamicBackendParameters::MaxFragmentShaderStorageBlocks);
             return;
         case GL_MAX_FRAGMENT_INPUT_COMPONENTS:
             *params = kFrontendMaxFragmentInputComponents;
@@ -1471,7 +1626,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = kFrontendMaxGeometryAtomicCounterBuffers;
             return;
         case GL_MAX_GEOMETRY_SHADER_STORAGE_BLOCKS:
-            *params = ClampStorageBlockCount(16); // TODO
+            *params = StageStorageBlockCount(&MG_Backend::DynamicBackendParameters::MaxGeometryShaderStorageBlocks);
             return;
         case GL_MAX_GEOMETRY_INPUT_COMPONENTS:
             *params = kFrontendMaxGeometryInputComponents;
@@ -1506,7 +1661,11 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = MG_State::pGLContext->IsCapabilityEnabled(CapabilityInput::Multisample) ? GL_TRUE : GL_FALSE;
             return;
         case GL_MIN_MAP_BUFFER_ALIGNMENT:
-            *params = 64; // TODO
+            // The same constant the map paths align to (MG_State/GLState/BufferState/
+            // PipeResource.h), never a literal: this number is a PROMISE about the pointers
+            // glMapBuffer and glMapBufferRange return, and the two used to be unrelated - the
+            // query said 64 while the pointers came out of a std::vector aligned to 16.
+            *params = static_cast<GLint>(MG_State::GLState::MIN_MAP_BUFFER_ALIGNMENT);
             return;
         case GL_MAX_LABEL_LENGTH:
             *params = 256; // TODO
@@ -1542,16 +1701,18 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = 0;
             return;
         case GL_MAX_TESS_CONTROL_SHADER_STORAGE_BLOCKS:
-            *params = ClampStorageBlockCount(16); // TODO
+            *params = StageStorageBlockCount(&MG_Backend::DynamicBackendParameters::MaxTessControlShaderStorageBlocks);
             return;
         case GL_MAX_TESS_EVALUATION_SHADER_STORAGE_BLOCKS:
-            *params = ClampStorageBlockCount(16); // TODO
+            *params =
+                StageStorageBlockCount(&MG_Backend::DynamicBackendParameters::MaxTessEvaluationShaderStorageBlocks);
             return;
         case GL_MAX_TEXTURE_LOD_BIAS:
             *params = 15; // TODO
             return;
         case GL_MAX_UNIFORM_LOCATIONS:
-            *params = 1024 * 4; // TODO
+            // The same constant the link's location allocator enforces - see ProgramObject.
+            *params = MG_State::GLState::ProgramObject::MAX_UNIFORM_LOCATIONS;
             return;
         case GL_MAX_VARYING_COMPONENTS:
             *params = kFrontendMaxVaryingComponents;
@@ -1571,7 +1732,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                           : MG_Backend::DynamicBackendParameters{}.MaxVertexImageUniforms;
             return;
         case GL_MAX_VERTEX_SHADER_STORAGE_BLOCKS:
-            *params = ClampStorageBlockCount(16); // TODO
+            *params = StageStorageBlockCount(&MG_Backend::DynamicBackendParameters::MaxVertexShaderStorageBlocks);
             return;
         case GL_MAX_VERTEX_UNIFORM_COMPONENTS:
             *params = kFrontendMaxVertexUniformComponents;
@@ -1881,6 +2042,24 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_UNIFORM_BUFFER_START:
             RecordIndexedOnlyGetterError(__func__, pname);
             return;
+        // glBindBufferBase/Range set the GENERIC binding point too (GL 4.6 core 6.1.1), and this
+        // is the one indexed-buffer family whose non-indexed query was never answered - so it
+        // fell through to INVALID_ENUM and left the caller's variable holding whatever was in its
+        // stack slot. _START/_SIZE stay indexed-only, exactly like their uniform-buffer siblings.
+        case GL_ATOMIC_COUNTER_BUFFER_BINDING:
+            if (const auto& obj =
+                    MG_State::pGLContext->GetBufferBindingSlot(BufferTarget::AtomicCounter).GetBoundObject()) {
+                *params = static_cast<GLint>(obj->GetExternalIndex());
+            } else {
+                *params = 0;
+            }
+            return;
+        case GL_ATOMIC_COUNTER_BUFFER_START:
+            RecordIndexedOnlyGetterError(__func__, pname);
+            return;
+        case GL_ATOMIC_COUNTER_BUFFER_SIZE:
+            RecordIndexedOnlyGetterError(__func__, pname);
+            return;
         case GL_UNPACK_ALIGNMENT:
             *params = MG_State::pGLContext->GetPixelStoreParam(PixelStoreParam::UnpackAlignment);
             return;
@@ -1935,9 +2114,6 @@ namespace MobileGL::MG_Impl::GLImpl {
             params[3] = vp.w();
             return;
         }
-        case GL_VIEWPORT_INDEX_PROVOKING_VERTEX:
-            *params = GL_LAST_VERTEX_CONVENTION;
-            return;
         case GL_MAX_ELEMENT_INDEX:
             *params = 1024 * 1024; // TODO
             return;
@@ -1954,7 +2130,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         const auto& activeBackendObject = MG_Backend::pActiveBackendObject;
         if (!activeBackendObject) {
-            MGLOG_E("activeBackendObject is not initialized!");
+            MGLOG_E_ONCE("activeBackendObject is not initialized!");
             return;
         }
         const auto& rendererInfo = activeBackendObject->GetRendererInfo();
@@ -2025,8 +2201,22 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_MAX_CLIP_DISTANCES:
             *params = dynamicParameters.MaxClipDistances;
             break;
+        // Both were a hard-coded GL_LAST_VERTEX_CONVENTION, derived from nothing. GL 4.6 table
+        // 23.65 permits GL_UNDEFINED_VERTEX for either, and that is what the backends report
+        // wherever they do not actually pin a convention - claiming one is a statement about
+        // which vertex of a primitive supplies gl_Layer / gl_ViewportIndex, and DirectGLES
+        // rasterizes only viewport 0 on a driver without GL_OES_viewport_array while
+        // DirectVulkan picks its provoking mode per pipeline. KHR-GLxx.viewport_array.query
+        // accepts all four values, and .provoking_vertex - which failed on both devices, in
+        // OPPOSITE directions - stops verifying as soon as either answer is undefined.
+        case GL_LAYER_PROVOKING_VERTEX:
+            *params = static_cast<GLint>(dynamicParameters.LayerProvokingVertex);
+            break;
+        case GL_VIEWPORT_INDEX_PROVOKING_VERTEX:
+            *params = static_cast<GLint>(dynamicParameters.ViewportIndexProvokingVertex);
+            break;
         case GL_MAX_COLOR_TEXTURE_SAMPLES:
-            *params = dynamicParameters.MaxColorTextureSamples;
+            *params = std::max(dynamicParameters.MaxColorTextureSamples, GetAdvertisedMaxSamples());
             break;
         case GL_MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS:
             *params = GetMaxCombinedUniformComponents(kFrontendMaxFragmentUniformComponents,
@@ -2056,7 +2246,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = dynamicParameters.MaxCubeMapTextureSize;
             break;
         case GL_MAX_DEPTH_TEXTURE_SAMPLES:
-            *params = dynamicParameters.MaxDepthTextureSamples;
+            *params = std::max(dynamicParameters.MaxDepthTextureSamples, GetAdvertisedMaxSamples());
             break;
         case GL_MAX_FRAMEBUFFER_WIDTH:
             *params = dynamicParameters.MaxFramebufferWidth;
@@ -2083,7 +2273,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = dynamicParameters.MaxComputeImageUniforms;
             break;
         case GL_MAX_INTEGER_SAMPLES:
-            *params = dynamicParameters.MaxIntegerSamples;
+            *params = std::max(dynamicParameters.MaxIntegerSamples, GetAdvertisedMaxSamples());
             break;
         case GL_MAX_RENDERBUFFER_SIZE:
             *params = dynamicParameters.MaxRenderbufferSize;
@@ -2116,18 +2306,19 @@ namespace MobileGL::MG_Impl::GLImpl {
                                                           static_cast<Uint64>(INT32_MAX)));
             break;
         case GL_MAX_ATOMIC_COUNTER_BUFFER_BINDINGS:
+            // NOT the frontend's binding-point array size: GetIndexedBufferQueryPointCount
+            // clamps this family to the range a lowered counter block can actually be served
+            // from, which is the same number glslang compiles a layout(binding = N) atomic_uint
+            // against and the same one glBindBufferBase validates an index against.
             *params = static_cast<GLint>(GetIndexedBufferQueryPointCount(BufferTarget::AtomicCounter));
             break;
         case GL_MAX_ATOMIC_COUNTER_BUFFER_SIZE:
             // The conformance suite splits this evenly across every advertised binding point and
             // binds all of them in one glBindBuffersRange
-            // (KHR-GL44.multi_bind.functional_bind_buffers_range), so the pair has to divide:
-            // 32 bytes over 36 binding points is a zero-sized range, which BindBufferRange
-            // rejects with INVALID_VALUE before it binds anything. Floor the advertised size at
-            // one counter per binding point.
-            *params = std::max<GLint>(
-                kFrontendMaxAtomicCounterBufferSize,
-                static_cast<GLint>(GetIndexedBufferQueryPointCount(BufferTarget::AtomicCounter) * sizeof(GLuint)));
+            // (KHR-GL44.multi_bind.functional_bind_buffers_range), so the pair has to divide -
+            // a zero-sized range is INVALID_VALUE before BindBufferRange binds anything. The
+            // shared constant is 16384 over 8 binding points, which divides.
+            *params = kFrontendMaxAtomicCounterBufferSize;
             break;
         case GL_MAX_TEXTURE_BUFFER_SIZE:
             *params = dynamicParameters.MaxTextureBufferSize;
@@ -2192,7 +2383,15 @@ namespace MobileGL::MG_Impl::GLImpl {
             params[1] = dynamicParameters.MaxViewportHeight;
             break;
         case GL_MAX_VIEWPORTS:
-            *params = dynamicParameters.MaxViewports;
+            // The frontend's own state width, not the backend's device limit. GL 4.3 core
+            // requires MAX_VIEWPORTS >= 16 and every indexed viewport entry point validates
+            // against RenderStateParameters::MAX_VIEWPORTS, so reporting anything else would
+            // either advertise viewports the state cannot hold or reject indices it can. A
+            // Vulkan device without the multiViewport feature reports maxViewports == 1, which
+            // limits what can be RASTERIZED to more than one rectangle (see the multiViewport
+            // gate in VulkanRenderer), not what the GL state can hold; caps.MaxViewports keeps
+            // carrying that device number for exactly that decision.
+            *params = static_cast<GLint>(RenderStateParameters::MAX_VIEWPORTS);
             break;
         case GL_MINOR_VERSION:
             *params = rendererInfo.RendererGLInfo.TargetGLVersion.Minor;
@@ -2241,14 +2440,14 @@ namespace MobileGL::MG_Impl::GLImpl {
                                                         : dynamicParameters.MaxDrawBuffers;
             break;
         case GL_MAX_SAMPLES:
-            *params = std::max(dynamicParameters.MaxSamples, kFrontendMaxSamples);
+            *params = GetAdvertisedMaxSamples();
             break;
         case GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT:
             // Float state (see GetFloatv); rounded to nearest for the integer query per GL 3.3 6.1.2.
             *params = static_cast<GLint>(std::lround(dynamicParameters.MaxTextureMaxAnisotropy));
             break;
         default:
-            MGLOG_E("glGetIntegerv: Invalid enum %s (0x%X)", MG_Util::ConvertGLEnumToString(pname).c_str(), pname);
+            MGLOG_D("glGetIntegerv: Invalid enum %s (0x%X)", MG_Util::ConvertGLEnumToString(pname).c_str(), pname);
             MG_State::pGLContext->RecordError(ErrorCode::InvalidEnum,
                                               MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "GetIntegerv",
                                                                            std::format("Invalid enum: 0x{:X}", pname)));

MobileGL/MG_Impl/GLImpl/Getter/GL_Getter.h

@@ -24,4 +24,8 @@ namespace MobileGL::MG_Impl::GLImpl {
     void GetInteger64i_v(GLenum target, GLuint index, GLint64* data);
     GLenum GetError();
     GLenum GetGraphicsResetStatus();
+    // The GL_MAX_SAMPLES value MobileGL advertises, i.e. the driver's value floored to the GL
+    // core minimum. Frontend multisample validators have to honour this ceiling for every
+    // format, otherwise MobileGL rejects a sample count it advertised itself.
+    GLint GetAdvertisedMaxSamples();
 } // namespace MobileGL::MG_Impl::GLImpl

MobileGL/MG_Impl/GLImpl/Program/GL_Program.cpp

@@ -21,6 +21,9 @@
 #include <MG_Backend/BackendObjects.h>
 
 namespace MobileGL::MG_Impl::GLImpl {
+    // The flattened uniform type these helpers used to take as a raw glslang::TType*
+    // pointing into the TProgram's pool allocator. See ProgramObject::TypeFacts.
+    using TypeFactsRef = const MG_State::GLState::ProgramObject::TypeFacts&;
     static GLint BoolToGLInt(bool value) {
         return value ? GL_TRUE : GL_FALSE;
     }
@@ -223,14 +226,14 @@ namespace MobileGL::MG_Impl::GLImpl {
         return false;
     }
 
-    GLint GetOpaqueUniformUnitLimit(const glslang::TType* type) {
+    GLint GetOpaqueUniformUnitLimit(const TypeFactsRef type) {
         const auto& dynamicParameters = MG_Backend::pActiveBackendObject->GetDynamicParameters();
-        if (type && type->isImage()) return dynamicParameters.MaxImageUnits;
-        if (type && type->isTexture()) return dynamicParameters.MaxCombinedTextureImageUnits;
+        if (type.isImage) return dynamicParameters.MaxImageUnits;
+        if (type.isTexture) return dynamicParameters.MaxCombinedTextureImageUnits;
         return 0;
     }
 
-    bool ValidateOpaqueUniformUnit(const char* functionName, const glslang::TType* type, GLint unit) {
+    bool ValidateOpaqueUniformUnit(const char* functionName, const TypeFactsRef type, GLint unit) {
         const GLint limit = GetOpaqueUniformUnitLimit(type);
         if (unit < 0 || unit >= limit) {
             MG_State::pGLContext->RecordError(
@@ -525,6 +528,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_UNIFORM_ARRAY_STRIDE:
         case GL_UNIFORM_MATRIX_STRIDE:
         case GL_UNIFORM_IS_ROW_MAJOR:
+        // GL 4.2 / ARB_shader_atomic_counters adds this one to the accepted set. Leaving it
+        // out did not merely lose the answer: the leftover GL_INVALID_ENUM is what made
+        // KHR-GL43.shader_atomic_counters.basic-program-query force a FAIL.
+        case GL_UNIFORM_ATOMIC_COUNTER_BUFFER_INDEX:
             break;
         default:
             MG_State::pGLContext->RecordError(
@@ -580,6 +587,11 @@ namespace MobileGL::MG_Impl::GLImpl {
             case GL_UNIFORM_IS_ROW_MAJOR:
                 params[i] = programObject->GetActiveUniformIsRowMajor(idx);
                 break;
+            case GL_UNIFORM_ATOMIC_COUNTER_BUFFER_INDEX:
+                // Index into the GL_ACTIVE_ATOMIC_COUNTER_BUFFERS list, -1 for every uniform
+                // that is not an atomic counter (GL 4.6 core table 7.6).
+                params[i] = programObject->GetActiveUniformAtomicCounterBufferIndex(idx);
+                break;
             default:
                 break;
             }
@@ -642,7 +654,13 @@ namespace MobileGL::MG_Impl::GLImpl {
             break;
         }
         case GL_ACTIVE_ATOMIC_COUNTER_BUFFERS:
-            *params = programObject->GetActiveAtomicCounterCount();
+            // Counter BUFFERS, not counters, and glslang's own getNumAtomicCounters() answers
+            // neither: the relaxed parse has already turned every atomic_uint into a plain uint
+            // member of a synthesized storage block by the time it builds its reflection, so it
+            // reports zero. The interface-query model recovers the buffers from those blocks and
+            // is what glGetProgramInterfaceiv(GL_ATOMIC_COUNTER_BUFFER, GL_ACTIVE_RESOURCES)
+            // already answers - the two queries are required to agree.
+            *params = ProgramInterface::GetActiveResourceCount(*programObject, GL_ATOMIC_COUNTER_BUFFER);
             MGLOG_D("%s: %s = %d", __func__, MG_Util::ConvertGLEnumToString(pname).c_str(), *params);
             break;
         case GL_ACTIVE_ATTRIBUTES:
@@ -662,7 +680,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             MGLOG_D("%s: %s = %d", __func__, MG_Util::ConvertGLEnumToString(pname).c_str(), *params);
             break;
         case GL_ACTIVE_UNIFORM_BLOCKS: // GL >= 3.1
-            *params = programObject->GetActiveUniformBlocksCount();
+            // Uniform blocks only. GetActiveUniformBlocksCount() is the internal block space,
+            // which also carries the storage blocks and the synthesized atomic counter blocks.
+            *params = programObject->GetGlUniformBlockCount();
             MGLOG_D("%s: %s = %d", __func__, MG_Util::ConvertGLEnumToString(pname).c_str(), *params);
             break;
         case GL_ACTIVE_UNIFORM_BLOCK_MAX_NAME_LENGTH: // ditto.
@@ -682,7 +702,11 @@ namespace MobileGL::MG_Impl::GLImpl {
             MGLOG_D("%s: %s = %d", __func__, MG_Util::ConvertGLEnumToString(pname).c_str(), *params);
             break;
         case GL_COMPUTE_WORK_GROUP_SIZE: { // GL >= 4.3
-            if (!programObject->GetLinkStatus() || programObject->GetShaderIndexByStage(ShaderStage::Compute) < 0) {
+            // "a linked program object with a compute shader" is one whose EXECUTABLE has the
+            // stage: the local size below is a link artifact, so an attached-but-not-yet-linked
+            // compute shader would answer this query with the previous link's (absent) value
+            // instead of the INVALID_OPERATION GL 4.6 core 7.13 asks for.
+            if (!programObject->GetLinkStatus() || !programObject->HasLinkedShaderStage(ShaderStage::Compute)) {
                 MG_State::pGLContext->RecordError(
                     ErrorCode::InvalidOperation,
                     MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
@@ -856,10 +880,14 @@ namespace MobileGL::MG_Impl::GLImpl {
     // demotion makes a dmat4 a mat4 in the shader and a mat4-shaped slot here - but because it
     // is ROUTED differently: the caller's component-by-component EbtDouble branch has to widen
     // each float back to the queried type, and it undoes the same padding itself.
-    Bool TryGatherFloatMatrixColumns(const glslang::TType* ttype, const char* pBase, void* params) {
-        if (ttype == nullptr || !ttype->isMatrix() || ttype->getBasicType() == glslang::EbtDouble) return false;
-        const Int columns = ttype->getMatrixCols();
-        const Int rows = ttype->getMatrixRows();
+    // Float matrices only, in both senses: a DOUBLE matrix never comes through here, whether its
+    // program was demoted (components are floats, the query is not) or kept its doubles (the
+    // column stride is a dvec4's, and the caller's converting branch already walks it component
+    // by component with the right one).
+    Bool TryGatherFloatMatrixColumns(const TypeFactsRef ttype, const char* pBase, void* params) {
+        if (!ttype.isMatrix || ttype.isDouble) return false;
+        const Int columns = ttype.matrixCols;
+        const Int rows = ttype.matrixRows;
         for (Int column = 0; column < columns; ++column) {
             Memcpy(static_cast<char*>(params) + static_cast<SizeT>(column) * rows * sizeof(GLfloat),
                    pBase + static_cast<SizeT>(column) * 4 * sizeof(GLfloat), rows * sizeof(GLfloat));
@@ -868,11 +896,12 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     // Bytes a uniform actually occupies in the global UBO. It is the tight GL type size for
-    // everything except a float matrix, whose padded columns make it wider. The rule itself
-    // lives on ProgramObject, because the pipeline composite's uniform refresh needs the same
-    // one and two copies of a layout rule is one too many.
-    SizeT UniformStorageSpanInBytes(const glslang::TType* ttype, SizeT tightSize) {
-        return MG_State::GLState::ProgramObject::UniformStorageSpanInBytes(ttype, tightSize);
+    // everything except a matrix, whose padded columns make it wider, and a `double` on a
+    // program whose modules were demoted, where it is half. The rule itself lives on
+    // ProgramObject, because the pipeline composite's uniform refresh needs the same one and
+    // two copies of a layout rule is one too many.
+    SizeT UniformStorageSpanInBytes(const TypeFactsRef ttype, SizeT tightSize, const Bool nativeFloat64) {
+        return MG_State::GLState::ProgramObject::UniformStorageSpanInBytes(ttype, tightSize, nativeFloat64);
     }
 
     void GetUniform_State(GLuint program, GLint location, void* params) {
@@ -904,20 +933,21 @@ namespace MobileGL::MG_Impl::GLImpl {
             auto offset = programObject->GetUniformOffset(location);
             auto size = programObject->GetUniformSizesInBytes(location);
             char* pUBO = (char*)programObject->MapUBO();
-            auto* ttype = programObject->GetUniformTType(location);
-            const SizeT span = UniformStorageSpanInBytes(ttype, size);
+            const auto& ttype = programObject->GetUniformTypeFacts(location);
+            const Bool nativeFloat64 = programObject->UsesNativeFloat64();
+            const SizeT span = UniformStorageSpanInBytes(ttype, size, nativeFloat64);
             if (pUBO == nullptr || offset == MG_State::GLState::ProgramObject::kInvalidUniformOffset ||
                 offset + span > programObject->GetUBOSize()) {
-                MGLOG_E("%s: uniform at program %u location %d has no backing storage; returning nothing", __func__,
+                MGLOG_E_ONCE("%s: uniform at program %u location %d has no backing storage; returning nothing", __func__,
                         program, location);
                 return;
             }
 
             if (!TryGatherFloatMatrixColumns(ttype, pUBO + offset, params)) {
                 // Never more than the uniform actually occupies. `size` is the GL type size,
-                // which for a `double` uniform is twice its storage - every 64-bit float is
-                // narrowed before the module reaches a backend, so the slot holds floats. The
-                // typed entry points (glGetUniformdv and friends) go through
+                // which on a DEMOTED program is twice a `double` uniform's storage - its 64-bit
+                // floats were narrowed before the module reached a backend, so the slot holds
+                // floats. The typed entry points (glGetUniformdv and friends) go through
                 // GetUniformScalar_State, which converts component by component; this raw
                 // copy has no type to convert with, so it is bounded rather than converted.
                 Memcpy(params, pUBO + offset, std::min<SizeT>(size, span));
@@ -958,11 +988,12 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto offset = programObject->GetUniformOffset(location);
         auto size = programObject->GetUniformSizesInBytes(location);
         char* pUBO = static_cast<char*>(programObject->MapUBO());
-        auto* ttype = programObject->GetUniformTType(location);
-        const SizeT span = UniformStorageSpanInBytes(ttype, size);
+        const auto& ttype = programObject->GetUniformTypeFacts(location);
+        const Bool nativeFloat64 = programObject->UsesNativeFloat64();
+        const SizeT span = UniformStorageSpanInBytes(ttype, size, nativeFloat64);
         if (pUBO == nullptr || offset == MG_State::GLState::ProgramObject::kInvalidUniformOffset ||
             offset + span > programObject->GetUBOSize()) {
-            MGLOG_E("%s: uniform at program %u location %d has no backing storage; returning nothing", __func__,
+            MGLOG_E_ONCE("%s: uniform at program %u location %d has no backing storage; returning nothing", __func__,
                     program, location);
             return;
         }
@@ -971,28 +1002,38 @@ namespace MobileGL::MG_Impl::GLImpl {
             if (TryGatherFloatMatrixColumns(ttype, pUBO + offset, params)) return;
         }
 
-        // A double-precision uniform is the one case where the stored component type differs
-        // from the DECLARED one for a non-opaque uniform: the shader's 64-bit floats are
-        // narrowed to 32 bits before the module reaches a backend
+        // A double-precision uniform is the one case where the stored component type can differ
+        // from the DECLARED one for a non-opaque uniform: on a DEMOTED program the shader's
+        // 64-bit floats were narrowed to 32 before the module reached the backend
         // (ShaderTranspiler::DemoteFloat64Pass), so what is in the global UBO is a float per
         // component, laid out exactly like the float-typed twin of this uniform - std140
         // 16-byte column stride for a matrix included. Reading it as a GLdouble would return
-        // two components reinterpreted as one. Read component by component and let GL's
+        // two components reinterpreted as one. A program that KEPT its doubles stores real ones
+        // at the dvec4 column stride instead, so the width and the stride both move; everything
+        // else about this walk is the same. Read component by component either way and let GL's
         // conversion rules (7.6: round to nearest for the integer queries) apply; the value
-        // widens back to the queried type, having lost precision at the glUniform*d that
-        // stored it and not here.
-        if (ttype->getBasicType() == glslang::EbtDouble) {
-            const Int columns = ttype->isMatrix() ? ttype->getMatrixCols() : 1;
-            const Int rows = ttype->isMatrix() ? ttype->getMatrixRows()
-                                               : (ttype->isVector() ? ttype->getVectorSize() : 1);
-            // std140 gives every matrix column its own 16-byte slot; a non-matrix is one
-            // tightly packed run and never reaches the stride at all.
-            const SizeT columnStride = 4 * sizeof(GLfloat);
+        // widens back to the queried type, having lost precision - where it lost any - at the
+        // glUniform*d that stored it and not here.
+        if (ttype.isDouble) {
+            const Int columns = ttype.isMatrix ? ttype.matrixCols : 1;
+            const Int rows = ttype.isMatrix ? ttype.matrixRows
+                                               : (ttype.isVector ? ttype.vectorSize : 1);
+            // A non-matrix is one tightly packed run and never reaches the stride at all.
+            const SizeT columnStride =
+                MG_State::GLState::ProgramObject::UniformMatrixColumnStride(ttype, nativeFloat64);
+            const SizeT componentSize = nativeFloat64 ? sizeof(GLdouble) : sizeof(GLfloat);
             for (Int column = 0; column < columns; ++column) {
                 for (Int row = 0; row < rows; ++row) {
-                    GLfloat component = 0.0f;
-                    Memcpy(&component, pUBO + offset + column * columnStride + row * sizeof(GLfloat),
-                           sizeof(component));
+                    GLdouble component = 0.0;
+                    if (nativeFloat64) {
+                        Memcpy(&component, pUBO + offset + column * columnStride + row * componentSize,
+                               sizeof(GLdouble));
+                    } else {
+                        GLfloat narrow = 0.0f;
+                        Memcpy(&narrow, pUBO + offset + column * columnStride + row * componentSize,
+                               sizeof(narrow));
+                        component = static_cast<GLdouble>(narrow);
+                    }
                     if constexpr (std::is_integral_v<T>) {
                         // Rounded to the nearest integer and clamped into the queried type's
                         // range, so a negative double read through glGetUniformuiv is 0
@@ -1057,21 +1098,20 @@ namespace MobileGL::MG_Impl::GLImpl {
             return;
         }
 
-        static Bool allowVSOnlyPrograms;
-        static Bool initialized = false;
-        if (!initialized) {
-            const auto& activeBackendObject = MG_Backend::pActiveBackendObject;
-            if (!activeBackendObject) {
-                MGLOG_E("activeBackendObject is not initialized!");
-                return;
-            }
-            const auto& rendererInfo = activeBackendObject->GetRendererInfo();
-            allowVSOnlyPrograms = (Int)rendererInfo.StaticBackendCapability.AllowVSOnlyPrograms;
-        }
+        // Read fresh every link, never latched in a static: the capability is
+        // per-backend, and a latch would freeze it across a backend teardown +
+        // re-initialization (the previous function-static memo here never even set
+        // its own initialized flag, so it re-read every call anyway - this makes
+        // the always-fresh behavior the stated one). A struct-field read per
+        // glLinkProgram costs nothing.
         const auto& activeBackendObject = MG_Backend::pActiveBackendObject;
-        if (activeBackendObject) {
-            programObject->SetMaxFragmentOutputColorNumber(activeBackendObject->GetDynamicParameters().MaxDrawBuffers);
+        if (!activeBackendObject) {
+            MGLOG_E_ONCE("activeBackendObject is not initialized!");
+            return;
         }
+        const Bool allowVSOnlyPrograms =
+            activeBackendObject->GetRendererInfo().StaticBackendCapability.AllowVSOnlyPrograms;
+        programObject->SetMaxFragmentOutputColorNumber(activeBackendObject->GetDynamicParameters().MaxDrawBuffers);
         programObject->Link(!allowVSOnlyPrograms);
     }
 
@@ -1152,7 +1192,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             SizeT writeSize = ItemCount * sizeof(T);
             if (size < writeSize) {
                 // Metadata bug: degrade to a clamped copy instead of killing the process.
-                MGLOG_E("%s: uniform size mismatch at program %u location %u: expected at least %zu bytes, got %zu "
+                MGLOG_E_ONCE("%s: uniform size mismatch at program %u location %u: expected at least %zu bytes, got %zu "
                         "bytes; clamping",
                         __func__, programObject.GetExternalIndex(), location, ItemCount * sizeof(T), size);
                 writeSize = size;
@@ -1173,7 +1213,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                 offset + byteOffsetInsideUniform + writeSize > uboSize) {
                 // Should not happen: linking gives every settable uniform backing
                 // storage. Log and drop the write instead of faulting.
-                MGLOG_E("%s: uniform at program %u location %u has no backing storage (ubo=%p offset=%u size=%zu "
+                MGLOG_E_ONCE("%s: uniform at program %u location %u has no backing storage (ubo=%p offset=%u size=%zu "
                         "uboSize=%zu); dropping write",
                         __func__, programObject.GetExternalIndex(), location, static_cast<void*>(pUBO), offset,
                         writeSize, uboSize);
@@ -1192,8 +1232,8 @@ namespace MobileGL::MG_Impl::GLImpl {
             Memcpy(pUBO + offset + byteOffsetInsideUniform, value, writeSize);
             programObject.MarkUBOContentDirty();
         } else {
-            auto* ttype = programObject.GetUniformTType(location);
-            if (!ttype->isTexture() && !ttype->isImage()) return;
+            const auto& ttype = programObject.GetUniformTypeFacts(location);
+            if (!ttype.isTexture && !ttype.isImage) return;
             if constexpr (!std::is_same_v<std::remove_cv_t<T>, GLint> || ItemCount != 1) {
                 MG_State::pGLContext->RecordError(
                     ErrorCode::InvalidOperation,
@@ -1264,17 +1304,45 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
     }
 
-    // glUniform*d / glUniformMatrix*dv. Neither needs a layout of its own any more: the
-    // transpile chain narrows every 64-bit float in the shader to 32 bits
+    // Whether the program a uniform write is about to land in stores 64-bit floats at their
+    // declared width. Answered off the PROGRAM, never off the live backend: it describes the
+    // modules that were actually built for it, and a backend with native fp64 still demotes a
+    // program whose vertex stage declares a Float64 input (see ProgramSpirvTask::GenerateSpirv).
+    // Nullptr - no current program, or a name that is not a program - answers false and lets the
+    // callee record the same error it always did.
+    Bool CurrentProgramUsesNativeFloat64() {
+        if (MG_State::pGLContext == nullptr) return false;
+        const auto& programObject = MG_State::pGLContext->GetProgramForUniform();
+        return programObject != nullptr && programObject->UsesNativeFloat64();
+    }
+
+    Bool NamedProgramUsesNativeFloat64(GLuint program) {
+        const auto& programObject = TryToGetProgramObject(program);
+        return programObject != nullptr && programObject->GetLinkStatus() && programObject->UsesNativeFloat64();
+    }
+
+    // glUniform*d / glUniformMatrix*dv. On a DEMOTED program neither needs a layout of its own:
+    // the transpile chain narrowed every 64-bit float in the shader to 32
     // (ShaderTranspiler::DemoteFloat64Pass) and the global UBO is laid out by reflecting that
     // demoted module, so a double uniform's storage IS a float uniform's - same offset, same
     // 4-byte components, same std140 column padding for matrices. Narrowing here, at the one
     // place the 64-bit value enters, and then handing the bytes to the ordinary float upload
-    // path is what keeps the two in step; a separate double-shaped layout here would write
+    // path is what keeps the two in step; a separate double-shaped layout there would write
     // 8-byte components into 4-byte slots and silently address the wrong ones.
     //
-    // The narrowing is the same static_cast the shader's own arithmetic now performs, so the
+    // The narrowing is the same static_cast the demoted shader's own arithmetic performs, so the
     // value the shader reads is the value glUniform*d was given, at float precision.
+    //
+    // On a program that KEPT its doubles the reverse is true and for the same reason: its global
+    // UBO really does hold 8-byte components, so narrowing would leave a float bit pattern in the
+    // low half of a double slot - which is not a precision loss but a garbage value. The 64-bit
+    // values go through unchanged then, and the upload path is width-agnostic (it is templated on
+    // the component type and bounded by the uniform's own slot span).
+    //
+    // Note TryToGetProgramObject / GetProgramForUniform run TWICE on this path, once for the
+    // width question and once inside the call below. That is a lookup and a join on an entry
+    // point no shader pack uses; the alternative is duplicating both functions' whole validation
+    // sequence here, which is the thing that must not drift.
     template <GLsizei ItemCount>
     void UniformvNarrowed_State(GLint location, GLsizei count, const GLdouble* value) {
         if (value == nullptr || count <= 0) {
@@ -1283,6 +1351,10 @@ namespace MobileGL::MG_Impl::GLImpl {
             Uniformv_State<ItemCount>(location, count, reinterpret_cast<const GLfloat*>(value));
             return;
         }
+        if (location != -1 && CurrentProgramUsesNativeFloat64()) {
+            Uniformv_State<ItemCount>(location, count, value);
+            return;
+        }
         Vector<GLfloat> narrowed(static_cast<SizeT>(count) * ItemCount);
         for (SizeT i = 0; i < narrowed.size(); ++i) narrowed[i] = static_cast<GLfloat>(value[i]);
         Uniformv_State<ItemCount>(location, count, narrowed.data());
@@ -1294,6 +1366,10 @@ namespace MobileGL::MG_Impl::GLImpl {
             ProgramUniformv_State<ItemCount>(program, location, count, reinterpret_cast<const GLfloat*>(value));
             return;
         }
+        if (location != -1 && NamedProgramUsesNativeFloat64(program)) {
+            ProgramUniformv_State<ItemCount>(program, location, count, value);
+            return;
+        }
         Vector<GLfloat> narrowed(static_cast<SizeT>(count) * ItemCount);
         for (SizeT i = 0; i < narrowed.size(); ++i) narrowed[i] = static_cast<GLfloat>(value[i]);
         ProgramUniformv_State<ItemCount>(program, location, count, narrowed.data());
@@ -1345,15 +1421,63 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
     }
 
-    // glUniformMatrix*dv / glProgramUniformMatrix*dv. Narrowed to the float form and handed
-    // straight to it: after DemoteFloat64Pass a `dmat4` uniform is a `mat4` in the shader and a
-    // mat4-shaped slot in the global UBO, columns padded to a vec4 and all. Everything else
-    // about the call - transpose handling, the array-element walk, the opaque-uniform refusal -
-    // is then the one implementation both spellings share.
+    // glUniformMatrix*dv / glProgramUniformMatrix*dv on a program that KEPT its doubles. Same
+    // walk as UniformMatrixfv_Object down to the last branch, and deliberately a copy of it
+    // rather than a template over the component type: the two differ in exactly one number that
+    // is not derivable from the component type alone - std140 pads a double matrix's column out
+    // to a dvec4 (32 bytes) unless the column is a dvec2, which is already 16 - and folding that
+    // into the float version would put a per-call branch on the hot glUniformMatrix4fv path
+    // Minecraft calls thousands of times a frame for a case no shader pack ever takes.
+    template <typename Program>
+    void UniformMatrixdvNative_Object(Program& programObject, GLint location, GLsizei count, GLboolean transpose,
+                                      const GLdouble* value, Int columns, Int rows,
+                                      const String& ownerDescription) {
+        const SizeT columnStride = rows <= 2 ? 2 * sizeof(GLdouble) : 4 * sizeof(GLdouble);
+        const SizeT componentCount = static_cast<SizeT>(columns) * static_cast<SizeT>(rows);
+        GLdouble column[4] = {};
+        for (GLint matrix = 0; matrix < count; ++matrix) {
+            if (matrix > 0 && !programObject.UniformLocationsAliasSameUniform(location, location + matrix)) break;
+            if (!programObject.IsValidUniformLocation(location + matrix)) {
+                RecordInvalidUniformLocationError("glUniformMatrixdv", location + matrix, ownerDescription);
+                return;
+            }
+            if (programObject.IsUniformOpaqueAtLocation(location + matrix)) {
+                MG_State::pGLContext->RecordError(
+                    ErrorCode::InvalidOperation,
+                    MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "glUniformMatrixdv",
+                                                 "Opaque uniforms cannot be set with matrix Uniform calls."));
+                return;
+            }
+            const GLdouble* source = value + static_cast<SizeT>(matrix) * componentCount;
+            for (Int c = 0; c < columns; ++c) {
+                for (Int r = 0; r < rows; ++r) {
+                    column[r] = transpose == GL_TRUE ? source[r * columns + c] : source[c * rows + r];
+                }
+                const SizeT byteOffset = static_cast<SizeT>(c) * columnStride;
+                switch (rows) {
+                case 2: Uniform_State<2>(programObject, location + matrix, column, byteOffset); break;
+                case 3: Uniform_State<3>(programObject, location + matrix, column, byteOffset); break;
+                default: Uniform_State<4>(programObject, location + matrix, column, byteOffset); break;
+                }
+            }
+        }
+    }
+
+    // glUniformMatrix*dv / glProgramUniformMatrix*dv. On a DEMOTED program this narrows to the
+    // float form and hands it straight over: after DemoteFloat64Pass a `dmat4` uniform is a
+    // `mat4` in the shader and a mat4-shaped slot in the global UBO, columns padded to a vec4
+    // and all. Everything else about the call - transpose handling, the array-element walk, the
+    // opaque-uniform refusal - is then the one implementation both spellings share. A program
+    // that kept its doubles gets the same walk at double width and the wider column stride.
     template <typename Program>
     void UniformMatrixdv_Object(Program& programObject, GLint location, GLsizei count, GLboolean transpose,
                                 const GLdouble* value, Int columns, Int rows) {
         if (value == nullptr || count <= 0) return;
+        if (programObject.UsesNativeFloat64()) {
+            UniformMatrixdvNative_Object(programObject, location, count, transpose, value, columns, rows,
+                                         "the current program object");
+            return;
+        }
         const SizeT componentCount = static_cast<SizeT>(columns) * static_cast<SizeT>(rows);
         Vector<GLfloat> narrowed(static_cast<SizeT>(count) * componentCount);
         for (SizeT i = 0; i < narrowed.size(); ++i) narrowed[i] = static_cast<GLfloat>(value[i]);
@@ -1695,7 +1819,10 @@ namespace MobileGL::MG_Impl::GLImpl {
             return GL_INVALID_INDEX;
         }
 
-        const auto& index = programObject->GetUniformBlockIndex(uniformBlockName);
+        // GetGlUniformBlockIndex, not GetUniformBlockIndex: the latter answers in the internal
+        // block space, which also resolves storage blocks and the synthesized atomic counter
+        // blocks. Neither is a uniform block (GL 4.6 core 7.6), so both are GL_INVALID_INDEX here.
+        const auto index = programObject->GetGlUniformBlockIndex(uniformBlockName);
         MGLOG_D("GBI prog=%u name='%s' -> %d", program, uniformBlockName ? uniformBlockName : "(null)", (Int)index);
         return index;
     }
@@ -1709,7 +1836,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                                              "Program object" + std::to_string(program) + " that has been linked."));
             return;
         }
-        if (!programObject->IsActiveUniformBlock(uniformBlockIndex)) {
+        if (!programObject->IsActiveGlUniformBlock(uniformBlockIndex)) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidValue,
                 MakeUnique<GenericErrorInfo>(
@@ -1720,8 +1847,11 @@ namespace MobileGL::MG_Impl::GLImpl {
                         std::to_string(program) + "."));
             return;
         }
+        // The GL_UNIFORM_BLOCK index space skips the storage and atomic counter blocks the
+        // block-keyed tables still carry; translate before touching them.
+        const Uint blockIndex = static_cast<Uint>(programObject->BlockIndexFromGlUniformBlock(uniformBlockIndex));
         MGLOG_D("UBB prog=%u idx=%u binding=%u", program, uniformBlockIndex, uniformBlockBinding);
-        programObject->SetUniformBlockBinding(uniformBlockIndex, uniformBlockBinding);
+        programObject->SetUniformBlockBinding(blockIndex, uniformBlockBinding);
     }
 
     void GetActiveUniformBlockiv_State(GLuint program, GLuint uniformBlockIndex, GLenum pname, GLint* params) {
@@ -1733,7 +1863,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                                              "Program object" + std::to_string(program) + " that has been linked."));
             return;
         }
-        if (!programObject->IsActiveUniformBlock(uniformBlockIndex)) {
+        if (!programObject->IsActiveGlUniformBlock(uniformBlockIndex)) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidValue,
                 MakeUnique<GenericErrorInfo>(
@@ -1744,61 +1874,68 @@ namespace MobileGL::MG_Impl::GLImpl {
                         std::to_string(program) + "."));
             return;
         }
+        // The GL_UNIFORM_BLOCK index space skips the storage and atomic counter blocks the
+        // block-keyed tables still carry; every accessor below is indexed by the block space.
+        const Uint blockIndex = static_cast<Uint>(programObject->BlockIndexFromGlUniformBlock(uniformBlockIndex));
         switch (pname) {
         case GL_UNIFORM_BLOCK_DATA_SIZE: {
-            *params = (GLint)programObject->GetUBOSizeAt(uniformBlockIndex);
+            *params = (GLint)programObject->GetUBOSizeAt(blockIndex);
             MGLOG_D("%s: GL_UNIFORM_BLOCK_DATA_SIZE = %d", __func__, *params);
             break;
         }
         case GL_UNIFORM_BLOCK_NAME_LENGTH: {
-            *params = (GLint)programObject->GetUniformBlockName(uniformBlockIndex).length() + 1;
+            *params = (GLint)programObject->GetUniformBlockName(blockIndex).length() + 1;
             MGLOG_D("%s: GL_UNIFORM_BLOCK_NAME_LENGTH = %d", __func__, *params);
             break;
         }
         case GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS: {
-            *params = programObject->GetUniformBlockActiveUniformCount(uniformBlockIndex);
+            *params = programObject->GetUniformBlockActiveUniformCount(blockIndex);
             MGLOG_D("%s: GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS = %d", __func__, *params);
             break;
         }
         case GL_UNIFORM_BLOCK_BINDING: {
-            *params = static_cast<GLint>(programObject->GetUniformBlockBinding(uniformBlockIndex));
+            *params = static_cast<GLint>(programObject->GetUniformBlockBinding(blockIndex));
             MGLOG_D("%s: GL_UNIFORM_BLOCK_BINDING = %d", __func__, *params);
             break;
         }
         case GL_UNIFORM_BLOCK_REFERENCED_BY_VERTEX_SHADER:
-            *params = BoolToGLInt(programObject->IsUniformBlockReferencedByStage(uniformBlockIndex, EShLangVertex));
+            *params = BoolToGLInt(programObject->IsUniformBlockReferencedByStage(blockIndex, EShLangVertex));
             MGLOG_D("%s: GL_UNIFORM_BLOCK_REFERENCED_BY_VERTEX_SHADER = %d", __func__, *params);
             break;
         case GL_UNIFORM_BLOCK_REFERENCED_BY_TESS_CONTROL_SHADER:
             *params =
-                BoolToGLInt(programObject->IsUniformBlockReferencedByStage(uniformBlockIndex, EShLangTessControl));
+                BoolToGLInt(programObject->IsUniformBlockReferencedByStage(blockIndex, EShLangTessControl));
             MGLOG_D("%s: GL_UNIFORM_BLOCK_REFERENCED_BY_TESS_CONTROL_SHADER = %d", __func__, *params);
             break;
         case GL_UNIFORM_BLOCK_REFERENCED_BY_TESS_EVALUATION_SHADER:
             *params =
-                BoolToGLInt(programObject->IsUniformBlockReferencedByStage(uniformBlockIndex, EShLangTessEvaluation));
+                BoolToGLInt(programObject->IsUniformBlockReferencedByStage(blockIndex, EShLangTessEvaluation));
             MGLOG_D("%s: GL_UNIFORM_BLOCK_REFERENCED_BY_TESS_EVALUATION_SHADER = %d", __func__, *params);
             break;
         case GL_UNIFORM_BLOCK_REFERENCED_BY_GEOMETRY_SHADER:
-            *params = BoolToGLInt(programObject->IsUniformBlockReferencedByStage(uniformBlockIndex, EShLangGeometry));
+            *params = BoolToGLInt(programObject->IsUniformBlockReferencedByStage(blockIndex, EShLangGeometry));
             MGLOG_D("%s: GL_UNIFORM_BLOCK_REFERENCED_BY_GEOMETRY_SHADER = %d", __func__, *params);
             break;
         case GL_UNIFORM_BLOCK_REFERENCED_BY_FRAGMENT_SHADER:
-            *params = BoolToGLInt(programObject->IsUniformBlockReferencedByStage(uniformBlockIndex, EShLangFragment));
+            *params = BoolToGLInt(programObject->IsUniformBlockReferencedByStage(blockIndex, EShLangFragment));
             MGLOG_D("%s: GL_UNIFORM_BLOCK_REFERENCED_BY_FRAGMENT_SHADER = %d", __func__, *params);
             break;
         case GL_UNIFORM_BLOCK_REFERENCED_BY_COMPUTE_SHADER:
-            *params = BoolToGLInt(programObject->IsUniformBlockReferencedByStage(uniformBlockIndex, EShLangCompute));
+            *params = BoolToGLInt(programObject->IsUniformBlockReferencedByStage(blockIndex, EShLangCompute));
             MGLOG_D("%s: GL_UNIFORM_BLOCK_REFERENCED_BY_COMPUTE_SHADER = %d", __func__, *params);
             break;
         case GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES: {
             // Member entries of an arrayed block are recorded against the first instance;
             // every instance of the array reports that shared member set (matches
             // GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS, which scans with the same owner index).
-            const Int ownerIndex = static_cast<Int>(programObject->GetUniformBlockMemberOwnerIndex(uniformBlockIndex));
+            //
+            // Both sides of the comparison are BLOCK indices: GetUniformBlockMemberOwnerIndex
+            // answers in that space, so the scan uses GetActiveUniformOwnerBlockIndex rather
+            // than the GL_UNIFORM_BLOCK-space GetActiveUniformBlockIndex.
+            const Int ownerIndex = static_cast<Int>(programObject->GetUniformBlockMemberOwnerIndex(blockIndex));
             GLint uniformIndexCount = 0;
             for (Uint uniformIndex = 0; uniformIndex < programObject->GetUniformCount(); ++uniformIndex) {
-                if (programObject->GetActiveUniformBlockIndex(uniformIndex) != ownerIndex) {
+                if (programObject->GetActiveUniformOwnerBlockIndex(uniformIndex) != ownerIndex) {
                     continue;
                 }
                 params[uniformIndexCount++] = static_cast<GLint>(uniformIndex);
@@ -1807,7 +1944,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             break;
         }
         default:
-            MGLOG_E("%s: unknown pname = %p %s", __func__, pname, MG_Util::ConvertGLEnumToString(pname).c_str());
+            MGLOG_D("%s: unknown pname = %p %s", __func__, pname, MG_Util::ConvertGLEnumToString(pname).c_str());
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidEnum,
                 MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
@@ -1828,7 +1965,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                                                  " is not a program object that has been linked."));
             return;
         }
-        if (!programObject->IsActiveUniformBlock(uniformBlockIndex)) {
+        if (!programObject->IsActiveGlUniformBlock(uniformBlockIndex)) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidValue,
                 MakeUnique<GenericErrorInfo>(
@@ -1838,7 +1975,8 @@ namespace MobileGL::MG_Impl::GLImpl {
                         "not the index of an active uniform block in program."));
             return;
         }
-        const auto& name = programObject->GetUniformBlockName(uniformBlockIndex);
+        const auto& name = programObject->GetUniformBlockName(
+            static_cast<Uint>(programObject->BlockIndexFromGlUniformBlock(uniformBlockIndex)));
         CopyStr(bufSize, length, uniformBlockName, name.c_str(), (GLsizei)name.length());
         MGLOG_D("%s: \"%s\" at uniformBlockIndex %02d, length = %d", __func__, uniformBlockName, uniformBlockIndex,
                 length ? *length : 0);
@@ -2836,6 +2974,73 @@ namespace MobileGL::MG_Impl::GLImpl {
         return ProgramInterface::GetResourceLocationIndex(*programObject, programInterface, name);
     }
 
+    // GL 4.6 §7.7. Every property this reports is one the GL_ATOMIC_COUNTER_BUFFER interface
+    // already carries, so this is a rename of glGetProgramResourceiv's props onto the older
+    // entry point's - and the two are required to agree, which is only true while both read the
+    // same model. It was a silent stub: it wrote nothing, raised nothing, and left every probe
+    // reading its own uninitialised output.
+    static Bool TryMapActiveAtomicCounterBufferProp(GLenum pname, GLenum& outProp) {
+        switch (pname) {
+        case GL_ATOMIC_COUNTER_BUFFER_BINDING:
+            outProp = GL_BUFFER_BINDING;
+            return true;
+        case GL_ATOMIC_COUNTER_BUFFER_DATA_SIZE:
+            outProp = GL_BUFFER_DATA_SIZE;
+            return true;
+        case GL_ATOMIC_COUNTER_BUFFER_ACTIVE_ATOMIC_COUNTERS:
+            outProp = GL_NUM_ACTIVE_VARIABLES;
+            return true;
+        case GL_ATOMIC_COUNTER_BUFFER_ACTIVE_ATOMIC_COUNTER_INDICES:
+            outProp = GL_ACTIVE_VARIABLES;
+            return true;
+        case GL_ATOMIC_COUNTER_BUFFER_REFERENCED_BY_VERTEX_SHADER:
+            outProp = GL_REFERENCED_BY_VERTEX_SHADER;
+            return true;
+        case GL_ATOMIC_COUNTER_BUFFER_REFERENCED_BY_TESS_CONTROL_SHADER:
+            outProp = GL_REFERENCED_BY_TESS_CONTROL_SHADER;
+            return true;
+        case GL_ATOMIC_COUNTER_BUFFER_REFERENCED_BY_TESS_EVALUATION_SHADER:
+            outProp = GL_REFERENCED_BY_TESS_EVALUATION_SHADER;
+            return true;
+        case GL_ATOMIC_COUNTER_BUFFER_REFERENCED_BY_GEOMETRY_SHADER:
+            outProp = GL_REFERENCED_BY_GEOMETRY_SHADER;
+            return true;
+        case GL_ATOMIC_COUNTER_BUFFER_REFERENCED_BY_FRAGMENT_SHADER:
+            outProp = GL_REFERENCED_BY_FRAGMENT_SHADER;
+            return true;
+        case GL_ATOMIC_COUNTER_BUFFER_REFERENCED_BY_COMPUTE_SHADER:
+            outProp = GL_REFERENCED_BY_COMPUTE_SHADER;
+            return true;
+        default:
+            return false;
+        }
+    }
+
+    void GetActiveAtomicCounterBufferiv(GLuint program, GLuint bufferIndex, GLenum pname, GLint* params) {
+        auto& programObject = TryToGetProgramForInterfaceQuery(program, __func__);
+        if (!programObject) return;
+        GLenum prop = GL_NONE;
+        if (!TryMapActiveAtomicCounterBufferProp(pname, prop)) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidEnum,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                             "pname is not an active atomic counter buffer property."));
+            return;
+        }
+        Vector<GLint> values;
+        if (!ProgramInterface::GetResourceProp(*programObject, GL_ATOMIC_COUNTER_BUFFER, bufferIndex, prop, values)) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidValue,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                             "bufferIndex is not an active atomic counter buffer index."));
+            return;
+        }
+        if (params == nullptr) return;
+        // GL_ATOMIC_COUNTER_BUFFER_ACTIVE_ATOMIC_COUNTER_INDICES is the only multi-value property
+        // here, and the caller sized its array from _ACTIVE_ATOMIC_COUNTERS.
+        for (SizeT i = 0; i < values.size(); ++i) params[i] = values[i];
+    }
+
     // GL 4.6 §7.6.2: <storageBlockIndex> is an active shader storage block index of <program>
     // - that is, exactly what glGetProgramResourceIndex(GL_SHADER_STORAGE_BLOCK) returned.
     // Since wave 2 that index is the interface-query layer's, so this is where the one index

MobileGL/MG_Impl/GLImpl/Program/GL_Program.h

@@ -140,6 +140,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                               const GLenum* props, GLsizei bufSize, GLsizei* length, GLint* params);
     GLint GetProgramResourceLocation(GLuint program, GLenum programInterface, const GLchar* name);
     GLint GetProgramResourceLocationIndex(GLuint program, GLenum programInterface, const GLchar* name);
+    void GetActiveAtomicCounterBufferiv(GLuint program, GLuint bufferIndex, GLenum pname, GLint* params);
     void ShaderStorageBlockBinding(GLuint program, GLuint storageBlockIndex, GLuint storageBlockBinding);
     void Uniform1d(GLint location, GLdouble v0);
     void Uniform1dv(GLint location, GLsizei count, const GLdouble* value);

MobileGL/MG_Impl/GLImpl/Program/ProgramInterface.cpp

@@ -19,7 +19,7 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
         // "<getAtomicCounterBlockName()>_<binding>" (ParseContextBase.cpp), one per GL
         // atomic-counter binding point. That block IS the GL_ATOMIC_COUNTER_BUFFER resource
         // and its trailing number IS GL_BUFFER_BINDING; its members stay GL_UNIFORMs.
-        constexpr const char* kAtomicCounterBlockPrefix = "gl_AtomicCounterBlock";
+        constexpr const char* kAtomicCounterBlockPrefix = MG_Util::ShaderTranspiler::ATOMIC_COUNTER_BLOCK_PREFIX;
 
         enum class BlockKind {
             Uniform,       // a real GL uniform block
@@ -81,19 +81,18 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
         // The enumerated spelling of an array resource is "name[0]". glslang already applies
         // that to uniforms and buffer variables (EShReflectionBasicArraySuffix), but never to
         // stage inputs/outputs, so those get it here.
-        String WithArraySuffix(const String& name, const glslang::TType* type) {
-            if (type == nullptr || !type->isArray() || EndsWithZeroSubscript(name)) return name;
+        String WithArraySuffix(const String& name, const ProgramObject::TypeFacts& type) {
+            if (!type.isArray || EndsWithZeroSubscript(name)) return name;
             return name + "[0]";
         }
 
         // GL_ARRAY_SIZE: element count for a sized array, 0 for a runtime-sized one
         // (a shader storage block's unsized trailing member), 1 for a non-array.
-        GLint ArraySizeOf(const glslang::TType* type, GLint reflectedSize) {
-            if (type != nullptr && type->isArray()) {
-                if (!type->isSizedArray()) return 0;
-                return type->getOuterArraySize();
-            }
-            return reflectedSize < 1 ? 1 : reflectedSize;
+        // `record.arraySize` is already the sized-array/reflected-size resolution; the only
+        // extra rule here is GL's 0 for a runtime-sized array.
+        GLint ArraySizeOf(const ProgramObject::ResourceReflection& record) {
+            if (record.type.isArray && !record.type.isSizedArray) return 0;
+            return record.arraySize;
         }
 
         // Two spellings name the same resource when they are equal, or differ only by the
@@ -174,22 +173,21 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
             return static_cast<GLint>(element);
         }
 
-        BlockKind ClassifyBlock(const glslang::TObjectReflection& block) {
+        BlockKind ClassifyBlock(const ProgramObject::BlockReflection& block) {
             if (std::strstr(block.name.c_str(), MG_Util::ShaderTranspiler::GLOBAL_UBO_NAME) != nullptr) {
                 return BlockKind::GlobalUbo;
             }
             if (IsAtomicCounterBlockName(block.name)) return BlockKind::AtomicCounter;
-            const glslang::TType* type = block.getType();
-            if (type != nullptr && type->getQualifier().storage == glslang::EvqBuffer) return BlockKind::Storage;
+            if (block.type.isBuffer) return BlockKind::Storage;
             return BlockKind::Uniform;
         }
 
         // std140/std430 column stride, the same vec4-rounded rule ProgramObject applies to
         // uniform matrices. 0 for a non-matrix.
-        GLint MatrixStrideOf(const glslang::TType* type) {
-            if (type == nullptr || !type->isMatrix()) return 0;
-            const bool rowMajor = type->getQualifier().layoutMatrix == glslang::ElmRowMajor;
-            const int strideVectorComponents = rowMajor ? type->getMatrixCols() : type->getMatrixRows();
+        GLint MatrixStrideOf(const ProgramObject::TypeFacts& type) {
+            if (!type.isMatrix) return 0;
+            const bool rowMajor = type.layoutMatrix == static_cast<Int>(glslang::ElmRowMajor);
+            const int strideVectorComponents = rowMajor ? type.matrixCols : type.matrixRows;
             constexpr int scalarSize = 4;
             const int vectorAlignment = (strideVectorComponents <= 1)    ? scalarSize
                                         : (strideVectorComponents == 2) ? 2 * scalarSize
@@ -197,9 +195,9 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
             return (vectorAlignment + 15) & ~15;
         }
 
-        GLint IsRowMajorOf(const glslang::TType* type) {
-            if (type == nullptr || !type->isMatrix()) return 0;
-            return type->getQualifier().layoutMatrix == glslang::ElmRowMajor ? 1 : 0;
+        GLint IsRowMajorOf(const ProgramObject::TypeFacts& type) {
+            if (!type.isMatrix) return 0;
+            return type.layoutMatrix == static_cast<Int>(glslang::ElmRowMajor) ? 1 : 0;
         }
 
         GLint MappedLocation(Int rawLocation) {
@@ -227,12 +225,12 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
         // Note the union is used even when it is empty: an array element nobody dereferenced has
         // no member bits and is genuinely referenced by nobody, which is the whole point - falling
         // back to the block's own mask there would restore the over-approximation.
-        Vector<Uint32> BuildBlockStagesFromMembers(const glslang::TProgram& reflection, Int blockCount) {
-            auto& mutableReflection = const_cast<glslang::TProgram&>(reflection);
+        Vector<Uint32> BuildBlockStagesFromMembers(const ProgramObject::LinkArtifacts& reflection,
+                                                    Int blockCount) {
             Vector<Uint32> stagesByBlock(static_cast<SizeT>(blockCount < 0 ? 0 : blockCount), 0u);
-            const Int uniformCount = mutableReflection.getNumUniformVariables();
+            const Int uniformCount = static_cast<Int>(reflection.uniformReflection.size());
             for (Int index = 0; index < uniformCount; ++index) {
-                const auto& uniform = mutableReflection.getUniform(index);
+                const auto& uniform = reflection.uniformReflection[index];
                 const Int owner = uniform.index;
                 if (owner < 0 || owner >= blockCount) continue;
                 stagesByBlock[static_cast<SizeT>(owner)] |= static_cast<Uint32>(uniform.stages);
@@ -250,7 +248,7 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
         // ss[1] and requires both to report the fragment stage, which only glslang's own
         // (deliberately over-approximating) block mask gets right. Storage and atomic-counter
         // blocks therefore keep that mask untouched.
-        Uint32 UniformBlockStages(const glslang::TObjectReflection& block, const Vector<Uint32>& stagesFromMembers,
+        Uint32 UniformBlockStages(const ProgramObject::BlockReflection& block, const Vector<Uint32>& stagesFromMembers,
                                   Int tIndex) {
             String arrayBase;
             Uint element = 0;
@@ -264,15 +262,15 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
             return stagesFromMembers[static_cast<SizeT>(tIndex)];
         }
 
-        void BuildBlocks(ProgramObject& program, const glslang::TProgram& reflection, Model& model,
+        void BuildBlocks(ProgramObject& program, const ProgramObject::LinkArtifacts& reflection, Model& model,
                          Vector<BlockKind>& blockKind, Vector<Int>& blockInterfaceIndex) {
-            const Int blockCount = const_cast<glslang::TProgram&>(reflection).getNumUniformBlocks();
+            const Int blockCount = static_cast<Int>(reflection.blockReflection.size());
             blockKind.assign(blockCount, BlockKind::Uniform);
             blockInterfaceIndex.assign(blockCount, -1);
             const Vector<Uint32> stagesFromMembers = BuildBlockStagesFromMembers(reflection, blockCount);
 
             for (Int tIndex = 0; tIndex < blockCount; ++tIndex) {
-                const auto& block = const_cast<glslang::TProgram&>(reflection).getUniformBlock(tIndex);
+                const auto& block = reflection.blockReflection[tIndex];
                 const BlockKind kind = ClassifyBlock(block);
                 blockKind[tIndex] = kind;
                 if (kind == BlockKind::AtomicCounter) {
@@ -293,7 +291,7 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
                     // glShaderStorageBlockBinding wins over the declaration (GL 4.6 §7.6.2 -
                     // exactly the same rule GL_UNIFORM_BLOCK follows through
                     // GetUniformBlockBinding below).
-                    const GLint declared = block.getBinding();
+                    const GLint declared = block.binding;
                     resource.bufferBinding = declared < 0 ? 0 : declared + BlockArrayElement(block.name);
                     const Int rebound = program.GetShaderStorageBlockBindingOverride(block.name);
                     if (rebound >= 0) resource.bufferBinding = static_cast<GLint>(rebound);
@@ -307,38 +305,53 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
             // GL_UNIFORM_BLOCK keeps the index space glUniformBlockBinding and
             // glGetActiveUniformBlockiv already use, so an index handed out here is usable
             // with them (which is exactly what the CTS does).
-            const Int glBlockCount = program.GetActiveUniformBlocksCount();
+            const Int glBlockCount = program.GetGlUniformBlockCount();
             for (Int glIndex = 0; glIndex < glBlockCount; ++glIndex) {
+                // The block-space index the block-keyed accessors want; the two spaces differ
+                // whenever the program also has a storage or atomic counter block, which
+                // glslang files under the same reflection list (no EShReflectionSeparateBuffers).
+                const Int blockIndex = program.BlockIndexFromGlUniformBlock(static_cast<Uint>(glIndex));
                 Resource resource;
-                resource.name = program.GetUniformBlockName(glIndex);
-                resource.bufferBinding = static_cast<GLint>(program.GetUniformBlockBinding(glIndex));
-                resource.bufferDataSize = static_cast<GLint>(program.GetUBOSizeAt(glIndex));
-                const Int tIndex = program.TProgramBlockIndex(static_cast<Uint>(glIndex));
+                resource.name = program.GetUniformBlockName(static_cast<Uint>(blockIndex));
+                resource.bufferBinding = static_cast<GLint>(program.GetUniformBlockBinding(static_cast<Uint>(blockIndex)));
+                resource.bufferDataSize = static_cast<GLint>(program.GetUBOSizeAt(static_cast<Uint>(blockIndex)));
+                const Int tIndex = program.TProgramBlockIndex(static_cast<Uint>(blockIndex));
                 if (tIndex >= 0 && tIndex < blockCount) {
-                    resource.stages = UniformBlockStages(const_cast<glslang::TProgram&>(reflection).getUniformBlock(tIndex),
+                    resource.stages = UniformBlockStages(reflection.blockReflection[tIndex],
                                                       stagesFromMembers, tIndex);
                 }
                 model.uniformBlocks.push_back(Move(resource));
             }
         }
 
-        void BuildUniformsAndBufferVariables(ProgramObject& program, const glslang::TProgram& reflection, Model& model,
+        void BuildUniformsAndBufferVariables(ProgramObject& program,
+                                             const ProgramObject::LinkArtifacts& reflection, Model& model,
                                              const Vector<BlockKind>& blockKind,
                                              const Vector<Int>& blockInterfaceIndex) {
-            const Uint uniformCount = program.GetUniformCount();
-            for (Uint glIndex = 0; glIndex < uniformCount; ++glIndex) {
-                const Int tIndex = program.TProgramUniformIndex(glIndex);
-                const auto& refl = const_cast<glslang::TProgram&>(reflection).getUniform(tIndex);
-                const glslang::TType* type = refl.getType();
+            // Walks the TPROGRAM uniform space, not the GL one. A buffer variable is not a GL
+            // uniform (GL 4.6 core 7.3.1) and DoReflection therefore keeps it out of the GL
+            // active-uniform index space - but GL_BUFFER_VARIABLE still has to enumerate it, and
+            // this is the only place that does. GL uniforms keep their GL index as their
+            // GL_UNIFORM resource index: the GL space is a subsequence of this one, so pushing
+            // the GL-visible entries in this order preserves the correspondence.
+            const Int tUniformCount = static_cast<Int>(reflection.uniformReflection.size());
+            for (Int tIndex = 0; tIndex < tUniformCount; ++tIndex) {
+                const auto& refl = ProgramObject::UniformAtIn(reflection, tIndex);
+                const auto& type = refl.type;
                 const Int owner = refl.index;
                 const BlockKind kind = (owner >= 0 && owner < static_cast<Int>(blockKind.size()))
                                            ? blockKind[owner]
                                            : BlockKind::GlobalUbo;
+                const Int glIndex = program.GlUniformIndexFromTProgram(tIndex);
+                // Everything except a buffer variable is enumerated through the GL space, so a
+                // uniform the relaxed parse swept out of it (a declared-but-dead default-block
+                // one) stays out of GL_UNIFORM too.
+                if (kind != BlockKind::Storage && glIndex < 0) continue;
 
                 Resource resource;
                 resource.name = refl.name;
                 resource.type = static_cast<GLenum>(refl.glDefineType);
-                resource.arraySize = ArraySizeOf(type, refl.size);
+                resource.arraySize = ArraySizeOf(refl);
                 resource.stages = static_cast<Uint32>(refl.stages);
 
                 if (kind == BlockKind::Storage) {
@@ -366,11 +379,12 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
                     resource.atomicCounterBufferIndex = blockInterfaceIndex[owner];
                     resource.location = -1;
                 } else {
-                    resource.blockIndex = program.GetActiveUniformBlockIndex(glIndex);
-                    resource.offset = program.GetActiveUniformOffset(glIndex);
-                    resource.arrayStride = program.GetActiveUniformArrayStride(glIndex);
-                    resource.matrixStride = program.GetActiveUniformMatrixStride(glIndex);
-                    resource.isRowMajor = program.GetActiveUniformIsRowMajor(glIndex);
+                    const Uint glUniformIndex = static_cast<Uint>(glIndex);
+                    resource.blockIndex = program.GetActiveUniformBlockIndex(glUniformIndex);
+                    resource.offset = program.GetActiveUniformOffset(glUniformIndex);
+                    resource.arrayStride = program.GetActiveUniformArrayStride(glUniformIndex);
+                    resource.matrixStride = program.GetActiveUniformMatrixStride(glUniformIndex);
+                    resource.isRowMajor = program.GetActiveUniformIsRowMajor(glUniformIndex);
                     // A member of a named uniform block has no location, whatever the
                     // frontend's own location table says (it hands one out to every uniform
                     // so glUniform* can address block members through the global UBO).
@@ -389,12 +403,16 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
                         static_cast<GLuint>(i));
                 }
             }
-            for (SizeT blockIndex = 0; blockIndex < model.uniformBlocks.size(); ++blockIndex) {
+            for (SizeT glBlockIndex = 0; glBlockIndex < model.uniformBlocks.size(); ++glBlockIndex) {
                 // Members of an arrayed block are reflected once, against instance [0].
-                const Int owner = static_cast<Int>(program.GetUniformBlockMemberOwnerIndex(static_cast<Uint>(blockIndex)));
+                // GetUniformBlockMemberOwnerIndex takes and answers BLOCK indices, while
+                // Resource::blockIndex is a GL_UNIFORM_BLOCK index, so translate both ways.
+                const Int blockIndex = program.BlockIndexFromGlUniformBlock(static_cast<Uint>(glBlockIndex));
+                const Int owner = program.GlUniformBlockIndexFromBlock(
+                    static_cast<Int>(program.GetUniformBlockMemberOwnerIndex(static_cast<Uint>(blockIndex))));
                 for (SizeT i = 0; i < model.uniforms.size(); ++i) {
                     if (model.uniforms[i].blockIndex == owner) {
-                        model.uniformBlocks[blockIndex].activeVariables.push_back(static_cast<GLuint>(i));
+                        model.uniformBlocks[glBlockIndex].activeVariables.push_back(static_cast<GLuint>(i));
                     }
                 }
             }
@@ -414,17 +432,13 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
         // program that redeclares `out gl_PerVertex { vec4 gl_Position; }` still carries
         // gl_PointSize and gl_ClipDistance through the block-unwrapping reflection, and they
         // are not part of its output interface.
-        Bool IsHiddenBlockMember(const glslang::TType* type) {
-            return type != nullptr && type->getBasicType() == glslang::EbtVoid;
-        }
+        Bool IsHiddenBlockMember(const ProgramObject::TypeFacts& type) { return type.isVoid; }
 
-        void BuildStageIO(ProgramObject& program, const glslang::TProgram& reflection, Model& model) {
-            auto& mutableReflection = const_cast<glslang::TProgram&>(reflection);
-
-            const Int inputCount = mutableReflection.getNumPipeInputs();
+        void BuildStageIO(ProgramObject& program, const ProgramObject::LinkArtifacts& reflection, Model& model) {
+            const Int inputCount = static_cast<Int>(reflection.pipeInputReflection.size());
             for (Int index = 0; index < inputCount; ++index) {
-                const auto& refl = mutableReflection.getPipeInput(index);
-                const glslang::TType* type = refl.getType();
+                const auto& refl = reflection.pipeInputReflection[index];
+                const auto& type = refl.type;
                 if (IsHiddenBlockMember(type)) continue;
                 Resource resource;
                 // The Vulkan-semantics parse reflects the vertex builtins under their SPIR-V
@@ -432,10 +446,10 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
                 const String& glName = ProgramObject::NormalizeBuiltinPipeInputName(refl.name);
                 resource.name = WithArraySuffix(glName, type);
                 resource.type = static_cast<GLenum>(refl.glDefineType);
-                resource.arraySize = ArraySizeOf(type, refl.size);
+                resource.arraySize = ArraySizeOf(refl);
                 resource.location = program.GetAttributeLocation(refl.name);
-                if (resource.location < 0) resource.location = MappedLocation(static_cast<Int>(refl.layoutLocation()));
-                resource.isPerPatch = (type != nullptr && type->getQualifier().patch) ? 1 : 0;
+                if (resource.location < 0) resource.location = MappedLocation(refl.location);
+                resource.isPerPatch = type.isPatch ? 1 : 0;
                 resource.stages = static_cast<Uint32>(refl.stages);
                 model.programInputs.push_back(Move(resource));
             }
@@ -447,16 +461,16 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
             // carries its own layout(location=N)), and a location then manufactures a color
             // index of 0 where GL requires -1
             // (KHR-GL43.program_interface_query.separate-programs-tess-control).
-            const Bool lastStageIsFragment = mutableReflection.getIntermediate(EShLangFragment) != nullptr;
-            const Int outputCount = mutableReflection.getNumPipeOutputs();
+            const Bool lastStageIsFragment = reflection.lastStageIsFragment;
+            const Int outputCount = static_cast<Int>(reflection.pipeOutputReflection.size());
             for (Int index = 0; index < outputCount; ++index) {
-                const auto& refl = mutableReflection.getPipeOutput(index);
-                const glslang::TType* type = refl.getType();
+                const auto& refl = reflection.pipeOutputReflection[index];
+                const auto& type = refl.type;
                 if (IsHiddenBlockMember(type)) continue;
                 Resource resource;
                 resource.name = WithArraySuffix(refl.name, type);
                 resource.type = static_cast<GLenum>(refl.glDefineType);
-                resource.arraySize = ArraySizeOf(type, refl.size);
+                resource.arraySize = ArraySizeOf(refl);
                 resource.location = MappedLocation(program.GetFragmentDataLocation(refl.name.c_str()));
                 if (resource.location < 0 || !lastStageIsFragment) {
                     // A built-in output (gl_FragDepth, gl_SampleMask) has no location, and a
@@ -467,11 +481,11 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
                     resource.locationIndex = program.GetFragmentDataIndex(refl.name.c_str());
                     // glBindFragDataLocationIndexed wins; otherwise the shader's
                     // layout(index = N), which the frag-data maps never saw.
-                    if (resource.locationIndex == 0 && type != nullptr && type->getQualifier().hasIndex()) {
-                        resource.locationIndex = static_cast<GLint>(type->getQualifier().layoutIndex);
+                    if (resource.locationIndex == 0 && type.hasIndex) {
+                        resource.locationIndex = static_cast<GLint>(type.layoutIndex);
                     }
                 }
-                resource.isPerPatch = (type != nullptr && type->getQualifier().patch) ? 1 : 0;
+                resource.isPerPatch = type.isPatch ? 1 : 0;
                 resource.stages = static_cast<Uint32>(refl.stages);
                 model.programOutputs.push_back(Move(resource));
             }
@@ -511,15 +525,14 @@ namespace MobileGL::MG_Impl::GLImpl::ProgramInterface {
         Model BuildModel(ProgramObject& program) {
             Model model;
             if (!program.GetLinkStatus()) return model;
-            const glslang::TProgram* reflection = program.GetReflection();
-            if (reflection == nullptr) return model;
+            const ProgramObject::LinkArtifacts& reflection = program.GetLinkReflection();
             model.valid = true;
 
             Vector<BlockKind> blockKind;
             Vector<Int> blockInterfaceIndex;
-            BuildBlocks(program, *reflection, model, blockKind, blockInterfaceIndex);
-            BuildUniformsAndBufferVariables(program, *reflection, model, blockKind, blockInterfaceIndex);
-            BuildStageIO(program, *reflection, model);
+            BuildBlocks(program, reflection, model, blockKind, blockInterfaceIndex);
+            BuildUniformsAndBufferVariables(program, reflection, model, blockKind, blockInterfaceIndex);
+            BuildStageIO(program, reflection, model);
             BuildXfb(program, model);
             return model;
         }

MobileGL/MG_Impl/GLImpl/Query/GL_Query.cpp

@@ -31,8 +31,15 @@ namespace MobileGL::MG_Impl::GLImpl {
             Bool ended = false;
             Bool resultCached = false;
             Uint64 cachedResult = 0;
-            // Transform feedback primitive counter at BeginQuery time.
+            // The transform feedback primitive counter matching this query's target, at
+            // BeginQuery time.
             Uint64 counterSnapshot = 0;
+            // Capture-draw counters at BeginQuery time: how many capture draws the CPU
+            // accounting had reproduced exactly, and how many of those it could not (a
+            // geometry stage amplifies). Their deltas decide whether the CPU result may
+            // stand in for the backend's.
+            Uint64 accountedCaptureDrawSnapshot = 0;
+            Uint64 geometryCaptureDrawSnapshot = 0;
         };
 
         // Query calls may arrive from any thread (launchers migrate the context
@@ -122,6 +129,46 @@ namespace MobileGL::MG_Impl::GLImpl {
             g_activeTimeElapsedQueryId = 0;
         }
 
+        // The CPU accounting counter a transform feedback query target reads: what the capture
+        // buffers took for GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN, and everything the capture
+        // stage assembled - a paused span included - for GL_PRIMITIVES_GENERATED. One counter
+        // for both targets would report the clamped written count as the generated one.
+        Uint64 TransformFeedbackCounterForTarget(GLenum target) {
+            return target == GL_PRIMITIVES_GENERATED
+                       ? MG_State::pGLContext->GetTransformFeedbackGeneratedCounter()
+                       : MG_State::pGLContext->GetTransformFeedbackPrimitiveCounter();
+        }
+
+        // The span's CPU accounting delta. Saturating: a snapshot left above its counter (a
+        // context switch between Begin and End, a counter that never moved) would otherwise
+        // wrap to 2^64-1, which GetQueryObjectuiv hands the app as 4294967295.
+        Uint64 TransformFeedbackCpuResult(const QueryObject* queryObject) {
+            const Uint64 counter = TransformFeedbackCounterForTarget(queryObject->target);
+            return counter > queryObject->counterSnapshot ? counter - queryObject->counterSnapshot : 0;
+        }
+
+        // Whether this ended span's result should come from the CPU accounting rather than from
+        // the backend query it also ran. Three conditions, all necessary:
+        //   * the backend asked for it (DirectGLES, whose ES driver counter is the unreliable
+        //     one; DirectVulkan never sets the bit and so is untouched by any of this);
+        //   * the target is PRIMITIVES_WRITTEN. GL_PRIMITIVES_GENERATED counts primitives
+        //     whether or not a capture is active, and the accounting only ever sees capture
+        //     draws, so the backend's counter is the more complete answer there;
+        //   * the span was fully accounted: at least one capture draw reached the accounting
+        //     (the instanced, indirect and multi-draw entry points do not call it at all, so a
+        //     span made of those is invisible to it) and none of them amplified through a
+        //     geometry stage, which the CPU cannot model.
+        Bool PrefersCpuTransformFeedbackResult(const QueryObject* queryObject) {
+            if (!MG_Backend::gBackendFunctionsTable.GL.PrefersCpuXfbPrimitiveAccounting) return false;
+            if (queryObject->target != GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN) return false;
+            if (MG_State::pGLContext->GetTransformFeedbackGeometryCaptureDraws() !=
+                queryObject->geometryCaptureDrawSnapshot) {
+                return false;
+            }
+            return MG_State::pGLContext->GetTransformFeedbackAccountedCaptureDraws() !=
+                   queryObject->accountedCaptureDrawSnapshot;
+        }
+
         // Shared GetQueryObject* implementation. Returns false when an error
         // was recorded and no value should be written back. `outValueProduced`, when given,
         // additionally distinguishes "succeeded with a value" from "succeeded but the result is not
@@ -407,7 +454,11 @@ namespace MobileGL::MG_Impl::GLImpl {
             const auto beginXfbPrimitivesQuery = MG_Backend::gBackendFunctionsTable.GL.BeginXfbPrimitivesQuery;
             queryObject->backendHandle =
                 beginXfbPrimitivesQuery ? beginXfbPrimitivesQuery(target == GL_PRIMITIVES_GENERATED) : nullptr;
-            queryObject->counterSnapshot = MG_State::pGLContext->GetTransformFeedbackPrimitiveCounter();
+            queryObject->counterSnapshot = TransformFeedbackCounterForTarget(target);
+            queryObject->accountedCaptureDrawSnapshot =
+                MG_State::pGLContext->GetTransformFeedbackAccountedCaptureDraws();
+            queryObject->geometryCaptureDrawSnapshot =
+                MG_State::pGLContext->GetTransformFeedbackGeometryCaptureDraws();
         } else if (isOcclusionQuery) {
             queryObject->backendHandle = MG_Backend::gBackendFunctionsTable.GL.BeginOcclusionQuery();
         } else {
@@ -448,12 +499,21 @@ namespace MobileGL::MG_Impl::GLImpl {
                 if (const auto endXfbPrimitivesQuery = MG_Backend::gBackendFunctionsTable.GL.EndXfbPrimitivesQuery) {
                     endXfbPrimitivesQuery(queryObject->backendHandle);
                 }
-                // Result comes from the GPU query at read time.
-            } else {
-                queryObject->cachedResult =
-                    MG_State::pGLContext->GetTransformFeedbackPrimitiveCounter() - queryObject->counterSnapshot;
+            }
+            // A backend query that is not going to be read is released here, not left to be
+            // collected later: the span is over, the driver object has nothing left to say.
+            // Ending it first is what makes that legal.
+            if (!queryObject->backendHandle || PrefersCpuTransformFeedbackResult(queryObject)) {
+                if (queryObject->backendHandle) {
+                    if (const auto deleteBackendQuery = MG_Backend::gBackendFunctionsTable.GL.DeleteBackendQuery) {
+                        deleteBackendQuery(queryObject->backendHandle);
+                    }
+                    queryObject->backendHandle = nullptr;
+                }
+                queryObject->cachedResult = TransformFeedbackCpuResult(queryObject);
                 queryObject->resultCached = true;
             }
+            // Otherwise the result comes from the GPU query at read time.
             queryObject->active = false;
             queryObject->ended = true;
             activeQueryId = 0;
@@ -505,6 +565,75 @@ namespace MobileGL::MG_Impl::GLImpl {
         queryObject->ended = true;
     }
 
+    void BeginConditionalRender(GLuint id, GLenum mode) {
+        // GL 4.6 core 10.9's eight modes. The _INVERTED half flips the sense of the predicate;
+        // the BY_REGION half only narrows WHERE an implementation is permitted to discard, so
+        // treating it as its whole-framebuffer sibling is what an implementation without region
+        // granularity does. The _NO_WAIT half is a permission to render rather than stall, not an
+        // obligation - see the resolve below.
+        Bool inverted = false;
+        switch (mode) {
+        case GL_QUERY_WAIT:
+        case GL_QUERY_NO_WAIT:
+        case GL_QUERY_BY_REGION_WAIT:
+        case GL_QUERY_BY_REGION_NO_WAIT:
+            inverted = false;
+            break;
+        case GL_QUERY_WAIT_INVERTED:
+        case GL_QUERY_NO_WAIT_INVERTED:
+        case GL_QUERY_BY_REGION_WAIT_INVERTED:
+        case GL_QUERY_BY_REGION_NO_WAIT_INVERTED:
+            inverted = true;
+            break;
+        default:
+            RecordQueryError(ErrorCode::InvalidEnum, __FUNCTION__, "mode is not a conditional render mode.");
+            return;
+        }
+
+        if (MG_State::pGLContext->IsConditionalRenderActive()) {
+            RecordQueryError(ErrorCode::InvalidOperation, __FUNCTION__, "Conditional rendering is already active.");
+            return;
+        }
+
+        {
+            const std::lock_guard<std::mutex> lock(g_queryObjectsMutex);
+            const auto* queryObject = FindQueryObjectLocked(id);
+            // A generated NAME is not yet a query object; it becomes one at its first use with a
+            // target (the same rule glIsQuery answers by).
+            if (!queryObject || (!queryObject->created && queryObject->target == 0)) {
+                RecordQueryError(ErrorCode::InvalidValue, __FUNCTION__, "id is not the name of a query object.");
+                return;
+            }
+            if (queryObject->active) {
+                RecordQueryError(ErrorCode::InvalidOperation, __FUNCTION__, "The query object is still active.");
+                return;
+            }
+            if (queryObject->target != GL_SAMPLES_PASSED && queryObject->target != GL_ANY_SAMPLES_PASSED &&
+                queryObject->target != GL_ANY_SAMPLES_PASSED_CONSERVATIVE) {
+                RecordQueryError(ErrorCode::InvalidOperation, __FUNCTION__,
+                                 "Conditional rendering requires an occlusion query object.");
+                return;
+            }
+        }
+
+        // Resolved ONCE, here, and by WAITING even for the _NO_WAIT modes: the spec lets those
+        // render instead of stalling, so always waiting is conforming and is the only choice that
+        // gives the whole block one deterministic verdict. Reading it per command instead would
+        // let a result that lands mid-block change the answer half way through.
+        Uint64 samplesPassed = 0;
+        if (!GetQueryObjectValue(id, GL_QUERY_RESULT, __FUNCTION__, samplesPassed)) return;
+        const Bool passed = samplesPassed != 0;
+        MG_State::pGLContext->BeginConditionalRender(id, mode, inverted ? passed : !passed);
+    }
+
+    void EndConditionalRender() {
+        if (!MG_State::pGLContext->IsConditionalRenderActive()) {
+            RecordQueryError(ErrorCode::InvalidOperation, __FUNCTION__, "Conditional rendering is not active.");
+            return;
+        }
+        MG_State::pGLContext->EndConditionalRender();
+    }
+
     void GetQueryiv(GLenum target, GLenum pname, GLint* params) {
         if (!params) {
             return;
@@ -648,4 +777,39 @@ namespace MobileGL::MG_Impl::GLImpl {
         if (!ValidateQueryStreamIndex(__FUNCTION__, target, index)) return;
         GetQueryiv(target, pname, params);
     }
+
+    void DestroyAllQueryObjects() {
+        // Detach the registry under the lock, release outside it - same discipline
+        // (and the same accepted teardown race) as DestroyAllSyncObjects. Without
+        // this drain, every query the app left undeleted survived full library
+        // teardown in the process-global registry: the objects and their backend
+        // wrappers leaked across Destroy/Initialize cycles, stale ids kept
+        // answering IsQuery == GL_TRUE in the re-initialized library, and a later
+        // glDeleteQueries could hand the OLD backend's handle to a DIFFERENT
+        // backend's DeleteBackendQuery, which casts it to the wrong wrapper type.
+        UnorderedMap<GLuint, QueryObject*> orphans;
+        {
+            const std::lock_guard<std::mutex> lock(g_queryObjectsMutex);
+            orphans.swap(g_liveQueryObjects);
+            g_activeTimeElapsedQueryId = 0;
+            g_activePrimitivesWrittenQueryId = 0;
+            g_activePrimitivesGeneratedQueryId = 0;
+            g_activeSamplesPassedQueryId = 0;
+        }
+        if (orphans.empty()) {
+            return;
+        }
+        // Backend handles must be released by the backend that created them, so
+        // this runs while the function table is still populated. Both backends'
+        // DeleteBackendQuery are generation-guarded, so a handle whose renderer
+        // or ES context is already gone frees only the wrapper.
+        const auto deleteBackendQuery = MG_Backend::gBackendFunctionsTable.GL.DeleteBackendQuery;
+        for (const auto& [_, queryObject] : orphans) {
+            if (deleteBackendQuery && queryObject->backendHandle) {
+                deleteBackendQuery(queryObject->backendHandle);
+            }
+            delete queryObject;
+        }
+        MGLOG_D("DestroyAllQueryObjects: reclaimed %zu query object(s) the app left undeleted", orphans.size());
+    }
 } // namespace MobileGL::MG_Impl::GLImpl

MobileGL/MG_Impl/GLImpl/Query/GL_Query.h

@@ -29,4 +29,18 @@ namespace MobileGL::MG_Impl::GLImpl {
     void GetQueryBufferObjecti64v(GLuint id, GLuint buffer, GLenum pname, GLintptr offset);
     void GetQueryBufferObjectui64v(GLuint id, GLuint buffer, GLenum pname, GLintptr offset);
     void QueryCounter(GLuint id, GLenum target);
+    // Conditional rendering (GL 4.6 core 10.9). Implemented here rather than beside the drawing
+    // entry points because the predicate is a QUERY OBJECT's result, and the object registry -
+    // with the lock that guards it - lives in this file.
+    void BeginConditionalRender(GLuint id, GLenum mode);
+    void EndConditionalRender();
+    // Destroys every still-registered query object exactly as DeleteQueries would.
+    // GL requires queries to die with their context; called only from full library
+    // teardown (DestroyImpl), where no context survives on any thread, so the
+    // process-global registry can be drained wholesale. Must run while the backend
+    // function table is still populated: each backend handle has to be released by
+    // the backend that created it, never by a later re-initialized one (whose
+    // DeleteBackendQuery would cast the wrapper to the wrong backend's type).
+    // Same contract as DestroyAllSyncObjects.
+    void DestroyAllQueryObjects();
 } // namespace MobileGL::MG_Impl::GLImpl

MobileGL/MG_Impl/GLImpl/RenderState/GL_RenderState.cpp

@@ -20,28 +20,118 @@ namespace MobileGL::MG_Impl::GLImpl {
         return std::clamp(static_cast<Float>(value), 0.0f, 1.0f);
     }
 
-    static Bool ValidateIndexedBlendCapability(GLenum target, GLuint index, const char* functionName) {
-        if (target != GL_BLEND) {
+    // GL 4.6 core 17.3.2 and 22.1 give exactly two indexed capabilities: GL_BLEND, indexed by
+    // draw buffer, and GL_SCISSOR_TEST, indexed by viewport. They have DIFFERENT bounds
+    // (MAX_DRAW_BUFFERS vs MAX_VIEWPORTS), so the limit is picked per target rather than shared.
+    static Bool ValidateIndexedCapability(GLenum target, GLuint index, const char* functionName) {
+        GLuint limit = 0;
+        const char* indexName = nullptr;
+        switch (target) {
+        case GL_BLEND:
+            limit = MG_State::GLState::FramebufferObject::MAX_DRAW_BUFFERS;
+            indexName = "Buffer";
+            break;
+        case GL_SCISSOR_TEST:
+            limit = RenderStateParameters::MAX_VIEWPORTS;
+            indexName = "Viewport";
+            break;
+        default:
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidEnum,
                 MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
-                                             "Only GL_BLEND is supported for indexed capability state."));
+                                             "Only GL_BLEND and GL_SCISSOR_TEST are supported for indexed "
+                                             "capability state."));
             return false;
         }
 
-        if (index >= MG_State::GLState::FramebufferObject::MAX_DRAW_BUFFERS) {
+        if (index >= limit) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidValue,
-                MakeUnique<GenericErrorInfo>(
-                    "MG_Impl/GLImpl", functionName,
-                    "Buffer index " + std::to_string(index) + " is out of range. Max supported is " +
-                        std::to_string(MG_State::GLState::FramebufferObject::MAX_DRAW_BUFFERS - 1) + "."));
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
+                                             String(indexName) + " index " + std::to_string(index) +
+                                                 " is out of range. Max supported is " + std::to_string(limit - 1) +
+                                                 "."));
             return false;
         }
 
         return true;
     }
 
+    // ------------------ ARB_viewport_array parameter validation ------------------
+    // All three families share the same two shapes, so they share the two checkers. GL 4.6 core
+    // 13.6.1/17.3.2: an out-of-range index is GL_INVALID_VALUE, and so is a negative width or
+    // height. `first + count == MAX_VIEWPORTS` is LEGAL - only strictly greater is an error,
+    // which KHR-GL43.viewport_array.api_errors checks explicitly in both directions.
+    static Bool ValidateViewportIndex(GLuint index, const char* functionName) {
+        if (index < RenderStateParameters::MAX_VIEWPORTS) return true;
+
+        MG_State::pGLContext->RecordError(
+            ErrorCode::InvalidValue,
+            MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
+                                         "Viewport index " + std::to_string(index) +
+                                             " is out of range. Max supported is " +
+                                             std::to_string(RenderStateParameters::MAX_VIEWPORTS - 1) + "."));
+        return false;
+    }
+
+    static Bool ValidateViewportRange(GLuint first, GLsizei count, const char* functionName) {
+        if (count < 0) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidValue,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName, "count must not be negative."));
+            return false;
+        }
+        // Widened before adding: first is a GLuint and count a GLsizei, so `first + count` in
+        // 32 bits can wrap past MAX_VIEWPORTS and let an out-of-range range through.
+        const Uint64 last = static_cast<Uint64>(first) + static_cast<Uint64>(count);
+        if (last > RenderStateParameters::MAX_VIEWPORTS) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidValue,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
+                                             "first (" + std::to_string(first) + ") + count (" +
+                                                 std::to_string(count) + ") exceeds GL_MAX_VIEWPORTS (" +
+                                                 std::to_string(RenderStateParameters::MAX_VIEWPORTS) + ")."));
+            return false;
+        }
+        return true;
+    }
+
+    template <typename T>
+    static Bool ValidateNonNegativeExtent(T width, T height, const char* functionName) {
+        if (width >= T(0) && height >= T(0)) return true;
+
+        MG_State::pGLContext->RecordError(
+            ErrorCode::InvalidValue,
+            MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName, "Width and height must be non-negative."));
+        return false;
+    }
+
+    // The array forms are all-or-nothing: one bad element rejects the whole call with a SINGLE
+    // GL_INVALID_VALUE and leaves every rectangle untouched. api_errors relies on both halves -
+    // it passes a full 16-element array with exactly one negative extent and then asserts the
+    // error queue holds exactly one entry.
+    template <typename T>
+    static Bool ValidateArrayExtents(GLsizei count, const T* v, const char* functionName) {
+        for (GLsizei i = 0; i < count; ++i) {
+            if (v[i * 4 + 2] >= T(0) && v[i * 4 + 3] >= T(0)) continue;
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidValue,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
+                                             "Width and height must be non-negative (element " + std::to_string(i) +
+                                                 ")."));
+            return false;
+        }
+        return true;
+    }
+
+    static Bool ValidateNonNullArray(const void* v, const char* functionName) {
+        if (v != nullptr) return true;
+        MG_State::pGLContext->RecordError(
+            ErrorCode::InvalidValue,
+            MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName, "value pointer cannot be null."));
+        return false;
+    }
+
     static Bool TryConvertBlendEquation(GLenum mode, const char* functionName,
                                         ::MobileGL::BlendEquation& outEquation) {
         outEquation = MG_Util::ConvertGLEnumToBlendEquation(mode);
@@ -93,16 +183,70 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void Viewport_State(GLint x, GLint y, GLsizei width, GLsizei height) {
-        if (width < 0 || height < 0) {
-            MG_State::pGLContext->RecordError(ErrorCode::InvalidValue,
-                                              MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "Viewport_State",
-                                                                           "Width abd height must be non-negative."));
-            return;
-        }
+        if (!ValidateNonNegativeExtent(width, height, "Viewport_State")) return;
 
         MG_State::pGLContext->SetViewport(IntVec4(x, y, width, height));
     }
 
+    // ------------------ ARB_viewport_array setters ------------------
+    void ViewportArrayv_State(GLuint first, GLsizei count, const GLfloat* v) {
+        if (!ValidateViewportRange(first, count, "ViewportArrayv_State")) return;
+        if (count == 0) return;
+        if (!ValidateNonNullArray(v, "ViewportArrayv_State")) return;
+        if (!ValidateArrayExtents(count, v, "ViewportArrayv_State")) return;
+
+        for (GLsizei i = 0; i < count; ++i) {
+            MG_State::pGLContext->SetViewportIndexed(first + static_cast<GLuint>(i),
+                                                     FloatVec4(v[i * 4 + 0], v[i * 4 + 1], v[i * 4 + 2], v[i * 4 + 3]));
+        }
+    }
+
+    void ViewportIndexedf_State(GLuint index, GLfloat x, GLfloat y, GLfloat w, GLfloat h) {
+        if (!ValidateViewportIndex(index, "ViewportIndexedf_State")) return;
+        if (!ValidateNonNegativeExtent(w, h, "ViewportIndexedf_State")) return;
+
+        MG_State::pGLContext->SetViewportIndexed(index, FloatVec4(x, y, w, h));
+    }
+
+    void ScissorArrayv_State(GLuint first, GLsizei count, const GLint* v) {
+        if (!ValidateViewportRange(first, count, "ScissorArrayv_State")) return;
+        if (count == 0) return;
+        if (!ValidateNonNullArray(v, "ScissorArrayv_State")) return;
+        if (!ValidateArrayExtents(count, v, "ScissorArrayv_State")) return;
+
+        for (GLsizei i = 0; i < count; ++i) {
+            MG_State::pGLContext->SetScissorBoxIndexed(first + static_cast<GLuint>(i),
+                                                       IntVec4(v[i * 4 + 0], v[i * 4 + 1], v[i * 4 + 2], v[i * 4 + 3]));
+        }
+    }
+
+    void ScissorIndexed_State(GLuint index, GLint left, GLint bottom, GLsizei width, GLsizei height) {
+        if (!ValidateViewportIndex(index, "ScissorIndexed_State")) return;
+        if (!ValidateNonNegativeExtent(width, height, "ScissorIndexed_State")) return;
+
+        MG_State::pGLContext->SetScissorBoxIndexed(index, IntVec4(left, bottom, width, height));
+    }
+
+    void DepthRangeArrayv_State(GLuint first, GLsizei count, const GLdouble* v) {
+        if (!ValidateViewportRange(first, count, "DepthRangeArrayv_State")) return;
+        if (count == 0) return;
+        if (!ValidateNonNullArray(v, "DepthRangeArrayv_State")) return;
+
+        for (GLsizei i = 0; i < count; ++i) {
+            MG_State::pGLContext->SetDepthRangeIndexed(
+                first + static_cast<GLuint>(i),
+                FloatVec2(ClampUnitFloat(static_cast<GLfloat>(v[i * 2 + 0])),
+                          ClampUnitFloat(static_cast<GLfloat>(v[i * 2 + 1]))));
+        }
+    }
+
+    void DepthRangeIndexed_State(GLuint index, GLdouble n, GLdouble f) {
+        if (!ValidateViewportIndex(index, "DepthRangeIndexed_State")) return;
+
+        MG_State::pGLContext->SetDepthRangeIndexed(
+            index, FloatVec2(ClampUnitFloat(static_cast<GLfloat>(n)), ClampUnitFloat(static_cast<GLfloat>(f))));
+    }
+
     void StencilOpSeparate_State(GLenum face, GLenum sfail, GLenum dpfail, GLenum dppass) {
         Bool applyFront = false;
         Bool applyBack = false;
@@ -175,12 +319,7 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void Scissor_State(GLint x, GLint y, GLsizei width, GLsizei height) {
-        if (width < 0 || height < 0) {
-            MG_State::pGLContext->RecordError(ErrorCode::InvalidValue,
-                                              MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "Scissor_State",
-                                                                           "Width abd height must be non-negative."));
-            return;
-        }
+        if (!ValidateNonNegativeExtent(width, height, "Scissor_State")) return;
 
         MG_State::pGLContext->SetScissorBox(IntVec4(x, y, width, height));
     }
@@ -336,7 +475,7 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     GLboolean IsEnabledi_State(GLenum target, GLuint index) {
-        if (!ValidateIndexedBlendCapability(target, index, "IsEnabledi_State")) {
+        if (!ValidateIndexedCapability(target, index, "IsEnabledi_State")) {
             return GL_FALSE;
         }
 
@@ -392,7 +531,14 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
         GLint values[4] = {};
         GetIntegeri_v(target, index, values);
-        *data = values[0] != 0 ? GL_TRUE : GL_FALSE;
+        // The ARB_viewport_array rectangles are the only multi-component indexed state that
+        // reaches here; writing element 0 alone would leave the caller's other three untouched.
+        const GLsizei components = target == GL_VIEWPORT || target == GL_SCISSOR_BOX
+            ? 4
+            : (target == GL_DEPTH_RANGE ? 2 : 1);
+        for (GLsizei i = 0; i < components; ++i) {
+            data[i] = values[i] != 0 ? GL_TRUE : GL_FALSE;
+        }
     }
 
     GLboolean IsEnabled_State(GLenum cap) {
@@ -725,7 +871,7 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void Disablei_State(GLenum target, GLuint index) {
-        if (!ValidateIndexedBlendCapability(target, index, "Disablei_State")) {
+        if (!ValidateIndexedCapability(target, index, "Disablei_State")) {
             return;
         }
 
@@ -743,7 +889,7 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void Enablei_State(GLenum target, GLuint index) {
-        if (!ValidateIndexedBlendCapability(target, index, "Enablei_State")) {
+        if (!ValidateIndexedCapability(target, index, "Enablei_State")) {
             return;
         }
 
@@ -797,6 +943,44 @@ namespace MobileGL::MG_Impl::GLImpl {
         Viewport_State(x, y, width, height);
     }
 
+    void ViewportArrayv(GLuint first, GLsizei count, const GLfloat* v) {
+        ViewportArrayv_State(first, count, v);
+    }
+
+    void ViewportIndexedf(GLuint index, GLfloat x, GLfloat y, GLfloat w, GLfloat h) {
+        ViewportIndexedf_State(index, x, y, w, h);
+    }
+
+    void ViewportIndexedfv(GLuint index, const GLfloat* v) {
+        // The index is validated before the pointer is touched: glViewportIndexedfv(MAX, nullptr)
+        // must be one GL_INVALID_VALUE, not a null dereference.
+        if (!ValidateViewportIndex(index, "ViewportIndexedfv")) return;
+        if (!ValidateNonNullArray(v, "ViewportIndexedfv")) return;
+        ViewportIndexedf_State(index, v[0], v[1], v[2], v[3]);
+    }
+
+    void ScissorArrayv(GLuint first, GLsizei count, const GLint* v) {
+        ScissorArrayv_State(first, count, v);
+    }
+
+    void ScissorIndexed(GLuint index, GLint left, GLint bottom, GLsizei width, GLsizei height) {
+        ScissorIndexed_State(index, left, bottom, width, height);
+    }
+
+    void ScissorIndexedv(GLuint index, const GLint* v) {
+        if (!ValidateViewportIndex(index, "ScissorIndexedv")) return;
+        if (!ValidateNonNullArray(v, "ScissorIndexedv")) return;
+        ScissorIndexed_State(index, v[0], v[1], v[2], v[3]);
+    }
+
+    void DepthRangeArrayv(GLuint first, GLsizei count, const GLdouble* v) {
+        DepthRangeArrayv_State(first, count, v);
+    }
+
+    void DepthRangeIndexed(GLuint index, GLdouble n, GLdouble f) {
+        DepthRangeIndexed_State(index, n, f);
+    }
+
     void StencilOpSeparate(GLenum face, GLenum sfail, GLenum dpfail, GLenum dppass) {
         StencilOpSeparate_State(face, sfail, dpfail, dppass);
     }

MobileGL/MG_Impl/GLImpl/RenderState/GL_RenderState.h

@@ -20,6 +20,16 @@ namespace MobileGL::MG_Impl::GLImpl {
     void Enablei(GLenum target, GLuint index);
     void BlendFunc(GLenum sfactor, GLenum dfactor);
     void Viewport(GLint x, GLint y, GLsizei width, GLsizei height);
+    // ARB_viewport_array (core since GL 4.1). Every one of these addresses the same 16-element
+    // indexed state the classic glViewport/glScissor/glDepthRange trio broadcasts to.
+    void ViewportArrayv(GLuint first, GLsizei count, const GLfloat* v);
+    void ViewportIndexedf(GLuint index, GLfloat x, GLfloat y, GLfloat w, GLfloat h);
+    void ViewportIndexedfv(GLuint index, const GLfloat* v);
+    void ScissorArrayv(GLuint first, GLsizei count, const GLint* v);
+    void ScissorIndexed(GLuint index, GLint left, GLint bottom, GLsizei width, GLsizei height);
+    void ScissorIndexedv(GLuint index, const GLint* v);
+    void DepthRangeArrayv(GLuint first, GLsizei count, const GLdouble* v);
+    void DepthRangeIndexed(GLuint index, GLdouble n, GLdouble f);
     void StencilOpSeparate(GLenum face, GLenum sfail, GLenum dpfail, GLenum dppass);
     void StencilOp(GLenum fail, GLenum zfail, GLenum zpass);
     void StencilMaskSeparate(GLenum face, GLuint mask);

MobileGL/MG_Impl/GLImpl/Sync/GL_Sync.cpp

@@ -8,6 +8,7 @@
 
 #include "GL_Sync.h"
 #include <MG_Backend/BackendObjects.h>
+#include <MG_State/GLState/Core.h>
 
 namespace MobileGL::MG_Impl::GLImpl {
     namespace {
@@ -35,6 +36,22 @@ namespace MobileGL::MG_Impl::GLImpl {
     } // namespace
 
     GLsync FenceSync(GLenum condition, GLbitfield flags) {
+        // GL 4.6 core 4.1.2: GL_SYNC_GPU_COMMANDS_COMPLETE is the only condition and the only
+        // legal flags value is zero; both violations return 0 rather than a handle. A caller that
+        // then hands the 0 back to glDeleteSync hits the glDeleteSync(0) no-op below.
+        if (condition != GL_SYNC_GPU_COMMANDS_COMPLETE) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidEnum,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                             "condition must be GL_SYNC_GPU_COMMANDS_COMPLETE."));
+            return nullptr;
+        }
+        if (flags != 0) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidValue,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__, "flags must be zero."));
+            return nullptr;
+        }
         auto* syncObject = new SyncObject;
         syncObject->condition = condition;
         syncObject->flags = flags;
@@ -64,6 +81,18 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void WaitSync(GLsync sync, GLbitfield flags, GLuint64 timeout) {
+        // GL 4.6 core 4.1.2: the server-side wait takes no flags and no finite timeout - both
+        // arguments exist only to be forward-compatible, and anything else is INVALID_VALUE.
+        // Neither backend ever honored a nonzero timeout (DirectGLES hard-codes
+        // 0/GL_TIMEOUT_IGNORED, DirectVulkan's queue ordering makes the wait implicit), so
+        // rejecting the call loses no wait that used to happen.
+        if (flags != 0 || timeout != GL_TIMEOUT_IGNORED) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidValue,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                             "flags must be zero and timeout must be GL_TIMEOUT_IGNORED."));
+            return;
+        }
         const auto* syncObject = FindSyncObject(sync);
         if (!syncObject) {
             return;

MobileGL/MG_Impl/GLImpl/Texture/Validators.cpp

@@ -15,6 +15,7 @@
 #include <MG_Util/Converters/MGToGL/TextureEnumConverter.h>
 #include <MG_Util/Converters/MGToMG/TextureEnumConverter.h>
 #include <MG_Util/Converters/MGToStr/TextureEnumConverter.h>
+#include <MG_Util/Metrics/TextureMetrics.h>
 
 namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
     Bool ValidateTextureTarget(TextureTarget target) {
@@ -312,9 +313,13 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
             return false;
         }
 
-        // TexImage in core 3.3 has no stencil-only upload path (that arrived with GL 4.4).
-        if (format == TextureInputFormat::StencilIndex) {
-            return recordInvalidOperation("STENCIL_INDEX is not a valid texture upload format");
+        // The stencil-only transfer path arrived with GL 4.4 / ARB_texture_stencil8, and only ever
+        // pairs with stencil-only storage: against a depth, depth-stencil or colour internal format
+        // STENCIL_INDEX keeps the pre-4.4 answer (GL CTS packed_pixels feeds exactly that pairing
+        // and expects INVALID_OPERATION).
+        if (format == TextureInputFormat::StencilIndex &&
+            internalFormat != TextureInternalFormat::StencilIndex8) {
+            return recordInvalidOperation("STENCIL_INDEX requires a stencil-only internal format");
         }
 
         if (IsDepthLikeInputFormat(format) != IsDepthLikeInternalFormat(internalFormat)) {
@@ -353,6 +358,63 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
         return true;
     }
 
+    Bool ValidateTextureLevelExists(const SharedPtr<MG_State::GLState::ITextureObject>& textureObject, Int level,
+                                    const char* caller) {
+        // A null object is somebody else's error to report - ValidateTextureObject runs
+        // first at every call site and has already recorded it.
+        if (!textureObject) return false;
+
+        const auto* mipmapTexture = MG_State::GLState::AsMipmapTexture(textureObject.get());
+        if (mipmapTexture == nullptr) {
+            // The only non-mipmap storage class is a buffer texture, and GL_TEXTURE_BUFFER is
+            // not a target glCopyImageSubData accepts at all (it is in the CTS's invalid-target
+            // set). Declining here is not the error code the spec asks for - that would be
+            // INVALID_ENUM from a target check this validator is not - but it does keep a
+            // texture with no image levels whatsoever from reaching a backend that would
+            // dereference a backend texture it never created.
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", caller,
+                                             "Texture has no mipmap levels to address."));
+            return false;
+        }
+
+        // What this number is, exactly, because two other things are almost it and neither is
+        // safe to assume: it is the number of level SLOTS the shadow has allocated - holes
+        // included, since MipmapStorage::AllocateLevel grows to level+1 and never fills the gap.
+        // For a cube map MipmapUploadTargetArray reports face +X's chain rather than the union.
+        //
+        // The guarantee that matters is one-sided: this count is always >= the level count the
+        // backends derive (VkTextureManager::GetUploadMipLevelCount stops at the first level
+        // with a non-positive extent, so it can only be shorter). That is the safe direction -
+        // no copy to a level the texture genuinely has is ever rejected here. It is NOT an
+        // exact match, so the backends keep their own range guard for the band in between: a
+        // chain with a hole (level 0 and 2 defined, 1 not) is accepted by this predicate and
+        // declined by the backend, which is a silent no-op rather than a copy. That band is a
+        // backend storage limitation, not a validation one - rejecting it here with
+        // INVALID_VALUE would be refusing a copy the spec permits.
+        const Uint levelCount = mipmapTexture->GetMipmapLevelCount();
+
+        if (levelCount == 0) {
+            // No image has ever been defined on this texture, so the fault is the texture,
+            // not the number: GL 4.6 core 18.3.2 asks for INVALID_OPERATION when an object a
+            // copy names is an incomplete texture.
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", caller,
+                                             "Texture has no image defined at any level."));
+            return false;
+        }
+        if (level < 0 || static_cast<Uint>(level) >= levelCount) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidValue,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", caller,
+                                             "Texture level does not exist in this texture."));
+            return false;
+        }
+        return true;
+    }
+
     Bool ValidateTextureObject(const SharedPtr<MG_State::GLState::ITextureObject>& textureObject) {
         if (!textureObject) {
             MG_State::pGLContext->RecordError(
@@ -458,26 +520,86 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
         }
     } // namespace
 
-    Bool ValidateBaseInternalFormatMatch(TextureInternalFormat format1, TextureInternalFormat format2) {
-        const auto unsizedFormat1 = MG_Util::ConvertInternalFormatToUnsized(format1);
-        const auto unsizedFormat2 = MG_Util::ConvertInternalFormatToUnsized(format2);
-        if (unsizedFormat1 != unsizedFormat2) {
-            // The 3-argument GenericErrorInfo constructor used to be spelled as a single
-            // std::format() call whose format string was the component name, so every
-            // diagnostic collapsed to the literal "MG_Impl/GLImpl". Format the message, then
-            // hand over component/function/message separately.
+    CopyImageTexelBlock ResolveCopyImageTexelBlock(TextureInternalFormat format, GLenum compressedFormat) {
+        CopyImageTexelBlock block{};
+        if (compressedFormat != GL_NONE) {
+            const auto info = MG_Util::GetCompressedFormatInfo(compressedFormat);
+            if (info.blockByteSize != 0) {
+                block.byteSize = info.blockByteSize;
+                block.blockWidth = info.blockWidth;
+                block.blockHeight = info.blockHeight;
+                block.compressed = true;
+                return block;
+            }
+        }
+        // The size MobileGL actually stores a texel of this format in, which for every format GL
+        // gives a required size is that required size. The handful of legacy formats GL leaves
+        // implementation-defined (R3_G3_B2, RGB4/5/10/12, RGBA2/12) have no view class in table
+        // 8.22 to be compared against anyway, and this is the size that decides whether a raw
+        // copy between them would in fact preserve the bytes.
+        block.byteSize = MG_Util::GetSizedInternalFormatSizeInBytes(format);
+        return block;
+    }
+
+    Bool ValidateCopyImageFormatCompatibility(const CopyImageTexelBlock& srcBlock,
+                                              const CopyImageTexelBlock& dstBlock) {
+        if (srcBlock.byteSize == 0 || dstBlock.byteSize == 0) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "ValidateCopyImageFormatCompatibility",
+                                             "A copied image has no storage whose texel size is known."));
+            return false;
+        }
+        if (srcBlock.byteSize != dstBlock.byteSize) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidOperation,
                 MakeUnique<GenericErrorInfo>(
-                    "MG_Impl/GLImpl", "ValidateBaseInternalFormatMatch",
-                    std::format("The base internal format of the two formats do not match ({} vs. {})",
-                                MG_Util::ConvertTextureInternalFormatToString(unsizedFormat1),
-                                MG_Util::ConvertTextureInternalFormatToString(unsizedFormat2))));
+                    "MG_Impl/GLImpl", "ValidateCopyImageFormatCompatibility",
+                    std::format("The two images' texel blocks are different sizes ({} vs. {} bytes), so the "
+                                "formats are not copy-compatible.",
+                                srcBlock.byteSize, dstBlock.byteSize)));
+            return false;
+        }
+        // Two compressed images additionally have to agree on the SHAPE of the block, not only
+        // its size: an 8-byte 4x4 block and a hypothetical 8-byte 8x8 one hold different texel
+        // counts, and GL 4.6 core 18.3.2 requires both dimensions to match.
+        if (srcBlock.compressed && dstBlock.compressed &&
+            (srcBlock.blockWidth != dstBlock.blockWidth || srcBlock.blockHeight != dstBlock.blockHeight)) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>(
+                    "MG_Impl/GLImpl", "ValidateCopyImageFormatCompatibility",
+                    std::format("The two compressed images have different block dimensions ({}x{} vs. {}x{}).",
+                                srcBlock.blockWidth, srcBlock.blockHeight, dstBlock.blockWidth,
+                                dstBlock.blockHeight)));
             return false;
         }
         return true;
     }
 
+    Bool ValidateCopyImageBlockAlignment(const CopyImageTexelBlock& block, Int x, Int y, Int width, Int height,
+                                         Int imageWidth, Int imageHeight, const char* endpointName) {
+        if (!block.compressed) return true;
+        const Int blockWidth = static_cast<Int>(block.blockWidth);
+        const Int blockHeight = static_cast<Int>(block.blockHeight);
+        if (blockWidth <= 1 && blockHeight <= 1) return true;
+        // The origin is unconditional; the extent gets the "or it reaches the edge of the image"
+        // exemption GL 4.6 core 18.3.2 grants, which is what lets a 16x16 BPTC image be copied
+        // whole even when the last block is partial.
+        const Bool originAligned = (x % blockWidth == 0) && (y % blockHeight == 0);
+        const Bool widthOk = (width % blockWidth == 0) || (x + width == imageWidth);
+        const Bool heightOk = (height % blockHeight == 0) || (y + height == imageHeight);
+        if (originAligned && widthOk && heightOk) return true;
+        MG_State::pGLContext->RecordError(
+            ErrorCode::InvalidValue,
+            MakeUnique<GenericErrorInfo>(
+                "MG_Impl/GLImpl", "ValidateCopyImageBlockAlignment",
+                std::format("The {} region [{}, {}] + [{} x {}] is not aligned to the {}x{} compressed block "
+                            "grid of a {} x {} image.",
+                            endpointName, x, y, width, height, blockWidth, blockHeight, imageWidth, imageHeight)));
+        return false;
+    }
+
     Bool ValidateCopyTexImageBaseFormatSubset(TextureInternalFormat destFormat, TextureInternalFormat srcFormat) {
         const auto unsizedDest = MG_Util::ConvertInternalFormatToUnsized(destFormat);
         const auto unsizedSrc = MG_Util::ConvertInternalFormatToUnsized(srcFormat);

MobileGL/MG_Impl/GLImpl/Texture/Validators.h

@@ -30,6 +30,16 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
                                                           TextureInternalFormat internalFormat,
                                                           TexturePixelDataType type);
     Bool ValidateTextureLevelWithUploadTarget(TextureUploadTarget target, Int level);
+    // "Is <level> a level this texture actually has?", which ValidateTextureLevelNumber above
+    // does NOT answer - that one only bounds the index by GL_MAX_TEXTURE_SIZE and knows nothing
+    // about the object. Entry points that resolve a level straight into a backend image
+    // subresource need this one: a level the texture never had is GL_INVALID_VALUE (GL 4.6 core
+    // 18.3.2), and passing it through instead reaches the driver as an out-of-range subresource.
+    // Note the error split is per-entry-point, so this is not universally reusable:
+    // glClearTexImage owes INVALID_OPERATION for the same out-of-range level and spells its own
+    // copy of this predicate in GL_Texture.cpp (GetClearTextureObject).
+    Bool ValidateTextureLevelExists(const SharedPtr<MG_State::GLState::ITextureObject>& textureObject, Int level,
+                                    const char* caller);
     Bool ValidateTextureObject(const SharedPtr<MG_State::GLState::ITextureObject>& textureObject);
     // Rejects the per-target default texture objects (name 0) with GL_INVALID_OPERATION for entry
     // points that require a GenTextures-created texture, e.g. TexStorage* ("An INVALID_OPERATION
@@ -40,8 +50,32 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
                                          TextureTarget target);
     Bool ValidateTextureSubImageOffsets(const SharedPtr<MG_State::GLState::ITextureObject>& textureObject, Int xoffset,
                                         Int width, Int yoffset = 0, Int height = 0, Int zoffset = 0, Int depth = 0);
-    // Exact base-format equality - what glCopyImageSubData's format compatibility needs.
-    Bool ValidateBaseInternalFormatMatch(TextureInternalFormat format1, TextureInternalFormat format2);
+    // The texel block of one glCopyImageSubData endpoint, resolved to the two things the
+    // compatibility rule actually asks about. `compressed` is not redundant with a block bigger
+    // than 1x1: it is what distinguishes "compressed, and so the region is measured in texels of
+    // a blocked image" from "uncompressed, and so it is measured in texels".
+    struct CopyImageTexelBlock {
+        SizeT byteSize = 0;
+        Uint blockWidth = 1;
+        Uint blockHeight = 1;
+        Bool compressed = false;
+    };
+    // `compressedFormat` is the GLenum a glCompressedTexImage* upload recorded for the level, or
+    // GL_NONE. It has to be asked for separately because MobileGL stores every compressed format
+    // in uncompressed storage (ConvertGLEnumToTextureInternalFormat), so the TextureInternalFormat
+    // alone can no longer tell a BPTC image from the RGBA8 backing it.
+    CopyImageTexelBlock ResolveCopyImageTexelBlock(TextureInternalFormat format, GLenum compressedFormat);
+    // GL 4.6 core 18.3.2: the two images must be COMPATIBLE, and compatible means their texel
+    // blocks are the same SIZE - not that they share a base internal format. RGBA32UI into
+    // RGBA32F is legal (both 128-bit) while RGBA8 into RGBA32F is not, and a compressed image
+    // pairs with an uncompressed one whose texel is as big as the compressed block.
+    Bool ValidateCopyImageFormatCompatibility(const CopyImageTexelBlock& srcBlock,
+                                              const CopyImageTexelBlock& dstBlock);
+    // GL 4.6 core 18.3.2: for a compressed image the region's origin must sit on a block
+    // boundary and its size must be a whole number of blocks - unless the edge it runs to is
+    // the edge of the image.
+    Bool ValidateCopyImageBlockAlignment(const CopyImageTexelBlock& block, Int x, Int y, Int width, Int height,
+                                         Int imageWidth, Int imageHeight, const char* endpointName);
     // GL 4.6 SS 8.6 subset rule for glCopyTexImage*: the read buffer must supply every component
     // the requested internalformat asks for, but may supply more.
     Bool ValidateCopyTexImageBaseFormatSubset(TextureInternalFormat destFormat, TextureInternalFormat srcFormat);

MobileGL/MG_Impl/GLImpl/VertexArray/GL_VertexArray.cpp

@@ -514,10 +514,17 @@ namespace MobileGL::MG_Impl::GLImpl {
     // recorded DataType is always Float64 - what IsLong adds is that this is the *unconverted* form,
     // as opposed to VertexAttribFormat(GL_DOUBLE), which asks for a float conversion.
     //
-    // Whether the backend can feed it is detected, not assumed: DirectVulkan needs shaderFloat64,
-    // and DirectGLES can never have it at all. A backend without it declines here, loudly - GL error
-    // plus a log line naming the reason - rather than accepting state no draw could honour and
-    // rendering garbage. The matching startup POST row is in MG_Util/SelfTest/DriverPost.cpp.
+    // Whether the backend can FEED it at full precision is detected, not assumed: DirectVulkan
+    // needs shaderFloat64, and DirectGLES can never have it at all. What that costs is PRECISION,
+    // not the call and no longer the array: GL 4.6 core 10.3.2 defines no error for a well-formed
+    // glVertexAttribLFormat, and a GL 4.3 context has 64-bit attributes in core, so declining the
+    // call would be non-conformant and would make the four pure state queries
+    // (VERTEX_ATTRIB_ARRAY_SIZE / _TYPE / _LONG / _RELATIVE_OFFSET) unanswerable
+    // (KHR-GL43.vertex_attrib_binding.basic-state1/3). The format is therefore RECORDED here and
+    // the array is NARROWED to float32 at draw, matching the fp64 demotion every shader already
+    // gets (DemoteFloat64Pass) - loudly, once, naming the cost. The matching startup POST row is in
+    // MG_Util/SelfTest/DriverPost.cpp; the draw-side narrowing is DirectGLES/Managers.cpp and, on
+    // DirectVulkan, VertexInputStateFactory's Float64 case.
     static void VertexAttribLFormatSeparate_State(const SharedPtr<MG_State::GLState::VertexArrayObject>& vao,
                                                   GLuint attribindex, GLint size, GLenum type,
                                                   GLuint relativeoffset) {
@@ -527,15 +534,12 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         if (!MG_Backend::pActiveBackendObject ||
             !MG_Backend::pActiveBackendObject->GetDynamicParameters().SupportsFloat64VertexAttributes) {
-            MGLOG_I("VertexAttribLFormat: attribute %u asked for a 64-bit (GL_DOUBLE) format, but this "
-                    "backend has no double-precision vertex attribute support - see the "
-                    "\"64-bit vertex attributes\" / \"shaderFloat64\" POST row for what that costs",
+            MGLOG_W_ONCE("VertexAttribLFormat: attribute %u asked for a 64-bit (GL_DOUBLE) format, but this "
+                    "backend has no double-precision vertex attribute support - the format is recorded "
+                    "and queryable, and the array is FETCHED AT FLOAT32 PRECISION at draw (the same "
+                    "narrowing the shader's dvec inputs already get); see the \"64-bit vertex "
+                    "attributes\" / \"shaderFloat64\" POST row for what that costs",
                     attribindex);
-            MG_State::pGLContext->RecordError(
-                ErrorCode::InvalidOperation,
-                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "VertexAttribLFormat",
-                                             "64-bit vertex attributes are not supported by this backend."));
-            return;
         }
 
         vao->SetAttributeFormatSeparate(attribindex, size, MG_Util::ConvertGLEnumToDataType(type),

MobileGL/MG_Impl/GLXImpl/Exporting/Definitions.cpp

@@ -166,32 +166,32 @@ MOBILEGL_GLX_API int glXSwapIntervalSGI(int interval) {
 
 // Legacy entry points some loaders probe for; harmless no-op stubs.
 MOBILEGL_GLX_API void glXCopyContext(Display*, void*, void*, unsigned long) {
-    MGLOG_W("glx: glXCopyContext is not supported");
+    MGLOG_W_ONCE("glx: glXCopyContext is not supported");
 }
 
 MOBILEGL_GLX_API unsigned long glXCreateGLXPixmap(Display*, void*, unsigned long) {
-    MGLOG_W("glx: glXCreateGLXPixmap is not supported");
+    MGLOG_W_ONCE("glx: glXCreateGLXPixmap is not supported");
     return 0;
 }
 
 MOBILEGL_GLX_API void glXDestroyGLXPixmap(Display*, unsigned long) {}
 
 MOBILEGL_GLX_API unsigned long glXCreatePixmap(Display*, void*, unsigned long, const int*) {
-    MGLOG_W("glx: glXCreatePixmap is not supported");
+    MGLOG_W_ONCE("glx: glXCreatePixmap is not supported");
     return 0;
 }
 
 MOBILEGL_GLX_API void glXDestroyPixmap(Display*, unsigned long) {}
 
 MOBILEGL_GLX_API unsigned long glXCreatePbuffer(Display*, void*, const int*) {
-    MGLOG_W("glx: glXCreatePbuffer is not supported");
+    MGLOG_W_ONCE("glx: glXCreatePbuffer is not supported");
     return 0;
 }
 
 MOBILEGL_GLX_API void glXDestroyPbuffer(Display*, unsigned long) {}
 
 MOBILEGL_GLX_API void glXUseXFont(unsigned long, int, int, int) {
-    MGLOG_W("glx: glXUseXFont is not supported");
+    MGLOG_W_ONCE("glx: glXUseXFont is not supported");
 }
 
 MOBILEGL_GLX_API void glXSelectEvent(Display*, unsigned long, unsigned long) {}

MobileGL/MG_Impl/GLXImpl/GLXImpl.cpp

@@ -149,7 +149,7 @@ namespace MobileGL::MG_Impl::GLXImpl {
                     fns->Sync = reinterpret_cast<decltype(fns->Sync)>(dlsym(fns->Library, "XSync"));
                 }
                 if (!fns->Valid()) {
-                    MGLOG_E("glx: failed to load libX11 entry points");
+                    MGLOG_E_ONCE("glx: failed to load libX11 entry points");
                 }
                 return fns;
             }();
@@ -314,7 +314,7 @@ namespace MobileGL::MG_Impl::GLXImpl {
             Uint32 width = 0;
             Uint32 height = 0;
             if (!QueryDrawableSize(dpy, drawable, width, height)) {
-                MGLOG_E("glx: XGetGeometry failed for drawable 0x%lx", drawable);
+                MGLOG_E_ONCE("glx: XGetGeometry failed for drawable 0x%lx", drawable);
                 return nullptr;
             }
 
@@ -326,7 +326,7 @@ namespace MobileGL::MG_Impl::GLXImpl {
             EGLSurface surface = EGLImpl::CreatePlatformWindowSurface(
                 context.Display, context.Config, reinterpret_cast<void*>(drawable), attribs);
             if (surface == EGL_NO_SURFACE) {
-                MGLOG_E("glx: failed to create window surface for drawable 0x%lx (%ux%u)", drawable,
+                MGLOG_E_ONCE("glx: failed to create window surface for drawable 0x%lx (%ux%u)", drawable,
                         width, height);
                 return nullptr;
             }
@@ -347,7 +347,7 @@ namespace MobileGL::MG_Impl::GLXImpl {
             const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
             EGLDisplay display = EnsureDisplay();
             if (display == EGL_NO_DISPLAY) {
-                MGLOG_E("glx: no EGL display");
+                MGLOG_E_ONCE("glx: no EGL display");
                 return nullptr;
             }
             EGLImpl::BindAPI(EGL_OPENGL_API);
@@ -376,13 +376,13 @@ namespace MobileGL::MG_Impl::GLXImpl {
             EGLint configCount = 0;
             if (!EGLImpl::ChooseConfig(display, configAttribs, &config, 1, &configCount) ||
                 configCount <= 0) {
-                MGLOG_E("glx: eglChooseConfig failed");
+                MGLOG_E_ONCE("glx: eglChooseConfig failed");
                 return nullptr;
             }
 
             EGLContext eglContext = EGLImpl::CreateContext(display, config, shareContext, contextAttribs);
             if (eglContext == EGL_NO_CONTEXT) {
-                MGLOG_E("glx: eglCreateContext failed");
+                MGLOG_E_ONCE("glx: eglCreateContext failed");
                 return nullptr;
             }
 
@@ -931,7 +931,7 @@ namespace MobileGL::MG_Impl::GLXImpl {
 
         if (!EGLImpl::MakeCurrent(object->Display, surface->Surface, surface->Surface,
                                   object->Context)) {
-            MGLOG_E("glx: eglMakeCurrent failed (drawable=0x%lx, ctx=%p)", drawable, context);
+            MGLOG_E_ONCE("glx: eglMakeCurrent failed (drawable=0x%lx, ctx=%p)", drawable, context);
             return 0;
         }
         t_current = {dpy, drawable, drawable, context};
@@ -943,7 +943,7 @@ namespace MobileGL::MG_Impl::GLXImpl {
         if (context && draw != read) {
             // MobileGL's backends reject split draw/read surfaces; bind the draw
             // drawable for both, which is what every real caller here needs.
-            MGLOG_W("glx: glXMakeContextCurrent draw 0x%lx != read 0x%lx, using draw for both", draw,
+            MGLOG_W_ONCE("glx: glXMakeContextCurrent draw 0x%lx != read 0x%lx, using draw for both", draw,
                     read);
         }
         const int result = MakeCurrent(dpy, draw, context);
@@ -958,7 +958,7 @@ namespace MobileGL::MG_Impl::GLXImpl {
         auto& surfaces = DrawableSurfaces();
         auto it = surfaces.find(drawable);
         if (it == surfaces.end()) {
-            MGLOG_W("glx: glXSwapBuffers with no surface for drawable 0x%lx", drawable);
+            MGLOG_W_ONCE("glx: glXSwapBuffers with no surface for drawable 0x%lx", drawable);
             return;
         }
         SyncSurfaceSize(dpy, drawable, it->second);

MobileGL/MG_Impl/GLXImpl/LookUp/LookUp.cpp

@@ -31,7 +31,7 @@ namespace MG_Impl::GLXImpl {
 #endif
         void* proc = MobileGL::MG_Impl::GetProcAddress(name);
         if (!proc) {
-            MGLOG_W("Failed to get function: %s", (const char*)name);
+            MGLOG_D("Failed to get function: %s", (const char*)name);
             return nullptr;
         }
 

MobileGL/MG_Impl/GetProcAddress.cpp

@@ -1403,7 +1403,7 @@ namespace MobileGL::MG_Impl {
         GETPROC(glFramebufferTextureMultiviewOVR, name);
         // GETPROC(glNamedFramebufferTextureMultiviewOVR, name);
 
-        MGLOG_W("GetProcAddress(%s) = nullptr!", name);
+        MGLOG_D("GetProcAddress(%s) = nullptr!", name);
         return nullptr;
     }
 } // namespace MobileGL::MG_Impl

MobileGL/MG_Impl/NSOpenGLImpl/NSOpenGLImpl.cpp

@@ -269,7 +269,7 @@ namespace MobileGL::MG_Impl::NSOpenGLImpl {
             }
             id metalLayerClass = reinterpret_cast<id>(objc_getClass("CAMetalLayer"));
             if (!metalLayerClass) {
-                MGLOG_E("NSOpenGLImpl: CAMetalLayer class not found");
+                MGLOG_E_ONCE("NSOpenGLImpl: CAMetalLayer class not found");
                 return nil;
             }
 
@@ -310,7 +310,7 @@ namespace MobileGL::MG_Impl::NSOpenGLImpl {
                                                        static_cast<GLint>(geometry.DrawableSize.width),
                                                        static_cast<GLint>(geometry.DrawableSize.height));
             if (error != kCGLNoError) {
-                MGLOG_E("NSOpenGLImpl: failed to attach drawable: %s", CGLImpl::ErrorString(error));
+                MGLOG_E_ONCE("NSOpenGLImpl: failed to attach drawable: %s", CGLImpl::ErrorString(error));
             }
         }
 
@@ -325,7 +325,7 @@ namespace MobileGL::MG_Impl::NSOpenGLImpl {
             }
             const auto error = CGLImpl::SetCurrentContext(context);
             if (error != kCGLNoError) {
-                MGLOG_E("NSOpenGLImpl: makeCurrentContext failed: %s", CGLImpl::ErrorString(error));
+                MGLOG_E_ONCE("NSOpenGLImpl: makeCurrentContext failed: %s", CGLImpl::ErrorString(error));
             }
         }
 
@@ -345,7 +345,7 @@ namespace MobileGL::MG_Impl::NSOpenGLImpl {
             }
             const auto error = CGLImpl::FlushDrawable(context);
             if (error != kCGLNoError) {
-                MGLOG_E("NSOpenGLImpl: flushBuffer failed: %s", CGLImpl::ErrorString(error));
+                MGLOG_E_ONCE("NSOpenGLImpl: flushBuffer failed: %s", CGLImpl::ErrorString(error));
             }
         }
 
@@ -377,7 +377,7 @@ namespace MobileGL::MG_Impl::NSOpenGLImpl {
                                                        static_cast<GLint>(geometry.DrawableSize.width),
                                                        static_cast<GLint>(geometry.DrawableSize.height));
             if (error != kCGLNoError) {
-                MGLOG_E("NSOpenGLImpl: update failed to attach drawable: %s", CGLImpl::ErrorString(error));
+                MGLOG_E_ONCE("NSOpenGLImpl: update failed to attach drawable: %s", CGLImpl::ErrorString(error));
                 return;
             }
             CGLImpl::UpdateContext(context);
@@ -421,7 +421,7 @@ namespace MobileGL::MG_Impl::NSOpenGLImpl {
             SEL selector = sel_registerName(selectorName);
             Method method = class_getInstanceMethod(cls, selector);
             if (!method) {
-                MGLOG_W("NSOpenGLImpl: missing instance method %s", selectorName);
+                MGLOG_W_ONCE("NSOpenGLImpl: missing instance method %s", selectorName);
                 return;
             }
             if (original) {
@@ -434,7 +434,7 @@ namespace MobileGL::MG_Impl::NSOpenGLImpl {
             SEL selector = sel_registerName(selectorName);
             Method method = class_getClassMethod(cls, selector);
             if (!method) {
-                MGLOG_W("NSOpenGLImpl: missing class method %s", selectorName);
+                MGLOG_W_ONCE("NSOpenGLImpl: missing class method %s", selectorName);
                 return;
             }
             method_setImplementation(method, replacement);
@@ -444,7 +444,7 @@ namespace MobileGL::MG_Impl::NSOpenGLImpl {
             Class pixelFormatClass = objc_getClass("NSOpenGLPixelFormat");
             Class contextClass = objc_getClass("NSOpenGLContext");
             if (!pixelFormatClass || !contextClass) {
-                MGLOG_W("NSOpenGLImpl: NSOpenGL classes are not loaded; hooks not installed");
+                MGLOG_W_ONCE("NSOpenGLImpl: NSOpenGL classes are not loaded; hooks not installed");
                 return false;
             }
 

MobileGL/MG_Impl/WGLImpl/Exporting/Definitions.cpp

@@ -56,7 +56,7 @@ extern "C" HGLRC WINAPI wglCreateLayerContext(HDC hdc, int iLayerPlane) {
 }
 
 extern "C" BOOL WINAPI wglCopyContext(HGLRC, HGLRC, UINT) {
-    MGLOG_W("wglCopyContext is not supported");
+    MGLOG_W_ONCE("wglCopyContext is not supported");
     SetLastError(ERROR_NOT_SUPPORTED);
     return FALSE;
 }
@@ -132,24 +132,24 @@ extern "C" DWORD WINAPI wglSwapMultipleBuffers(UINT n, CONST WGLSWAP* ps) {
 // ---- Font rendering (legacy immediate-mode feature; not supported) ----
 
 extern "C" BOOL WINAPI wglUseFontBitmapsA(HDC, DWORD, DWORD, DWORD) {
-    MGLOG_W("wglUseFontBitmapsA is not supported");
+    MGLOG_W_ONCE("wglUseFontBitmapsA is not supported");
     return FALSE;
 }
 
 extern "C" BOOL WINAPI wglUseFontBitmapsW(HDC, DWORD, DWORD, DWORD) {
-    MGLOG_W("wglUseFontBitmapsW is not supported");
+    MGLOG_W_ONCE("wglUseFontBitmapsW is not supported");
     return FALSE;
 }
 
 extern "C" BOOL WINAPI wglUseFontOutlinesA(HDC, DWORD, DWORD, DWORD, FLOAT, FLOAT, int,
                                                  LPGLYPHMETRICSFLOAT) {
-    MGLOG_W("wglUseFontOutlinesA is not supported");
+    MGLOG_W_ONCE("wglUseFontOutlinesA is not supported");
     return FALSE;
 }
 
 extern "C" BOOL WINAPI wglUseFontOutlinesW(HDC, DWORD, DWORD, DWORD, FLOAT, FLOAT, int,
                                                  LPGLYPHMETRICSFLOAT) {
-    MGLOG_W("wglUseFontOutlinesW is not supported");
+    MGLOG_W_ONCE("wglUseFontOutlinesW is not supported");
     return FALSE;
 }
 

MobileGL/MG_Impl/WGLImpl/WGLImpl.cpp

@@ -215,7 +215,7 @@ namespace MobileGL::MG_Impl::WGLImpl {
             Uint32 width = 0;
             Uint32 height = 0;
             if (!QueryClientSize(hwnd, width, height)) {
-                MGLOG_E("wgl: GetClientRect failed for HWND %p", hwnd);
+                MGLOG_E_ONCE("wgl: GetClientRect failed for HWND %p", hwnd);
                 return nullptr;
             }
 
@@ -227,7 +227,7 @@ namespace MobileGL::MG_Impl::WGLImpl {
             EGLSurface surface =
                 EGLImpl::CreatePlatformWindowSurface(context.Display, context.Config, hwnd, attribs);
             if (surface == EGL_NO_SURFACE) {
-                MGLOG_E("wgl: failed to create window surface for HWND %p (%ux%u)", hwnd, width, height);
+                MGLOG_E_ONCE("wgl: failed to create window surface for HWND %p (%ux%u)", hwnd, width, height);
                 return nullptr;
             }
 
@@ -244,7 +244,7 @@ namespace MobileGL::MG_Impl::WGLImpl {
             const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
             EGLDisplay display = EnsureDisplay();
             if (display == EGL_NO_DISPLAY) {
-                MGLOG_E("wgl: no EGL display");
+                MGLOG_E_ONCE("wgl: no EGL display");
                 return nullptr;
             }
             EGLImpl::BindAPI(EGL_OPENGL_API);
@@ -275,13 +275,13 @@ namespace MobileGL::MG_Impl::WGLImpl {
             EGLConfig config = nullptr;
             EGLint configCount = 0;
             if (!EGLImpl::ChooseConfig(display, configAttribs, &config, 1, &configCount) || configCount <= 0) {
-                MGLOG_E("wgl: eglChooseConfig failed");
+                MGLOG_E_ONCE("wgl: eglChooseConfig failed");
                 return nullptr;
             }
 
             EGLContext eglContext = EGLImpl::CreateContext(display, config, shareContext, contextAttribs);
             if (eglContext == EGL_NO_CONTEXT) {
-                MGLOG_E("wgl: eglCreateContext failed");
+                MGLOG_E_ONCE("wgl: eglCreateContext failed");
                 return nullptr;
             }
 
@@ -612,7 +612,7 @@ namespace MobileGL::MG_Impl::WGLImpl {
         auto& surfaces = WindowSurfaces();
         auto it = surfaces.find(hwnd);
         if (it == surfaces.end()) {
-            MGLOG_W("wglSwapBuffers: no surface for HWND %p", hwnd);
+            MGLOG_W_ONCE("wglSwapBuffers: no surface for HWND %p", hwnd);
             return FALSE;
         }
         SyncSurfaceSize(hwnd, it->second);
@@ -685,7 +685,7 @@ namespace MobileGL::MG_Impl::WGLImpl {
         }
 
         if (!EGLImpl::MakeCurrent(object->Display, surface->Surface, surface->Surface, object->Context)) {
-            MGLOG_E("wglMakeCurrent: eglMakeCurrent failed (hdc=%p, hglrc=%p)", hdc, hglrc);
+            MGLOG_E_ONCE("wglMakeCurrent: eglMakeCurrent failed (hdc=%p, hglrc=%p)", hdc, hglrc);
             return FALSE;
         }
         t_current = {hdc, hglrc};

MobileGL/MG_IntegrationTest/CMakeLists.txt

@@ -24,9 +24,14 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 set(MGL_ITEST_ROOT ${CMAKE_CURRENT_LIST_DIR}/../..)
 
-# Only meaningful where MobileGL_s exists (i.e. not Android).
-if (NOT TARGET MobileGL_s)
-    message(STATUS "MobileGL_s is not available; skipping the integration test module")
+# Desktop links the static implementation directly. Android runs the same
+# executable from adb shell and links the shipping shared library instead.
+if (ANDROID)
+    set(MGL_ITEST_MOBILEGL_TARGET MobileGL)
+elseif (TARGET MobileGL_s)
+    set(MGL_ITEST_MOBILEGL_TARGET MobileGL_s)
+else()
+    message(STATUS "No MobileGL library target is available; skipping the integration test module")
     return()
 endif()
 
@@ -54,6 +59,7 @@ add_executable(MobileGLIntegrationTest
     Scenarios/AsyncCompileScenario.cpp
     Scenarios/XfbAfterClipDistanceScenario.cpp
     Scenarios/ThreeChannelAttachmentScenario.cpp
+    Scenarios/SnormAttachmentScenario.cpp
     Scenarios/PipelineFailureScenario.cpp
     Scenarios/AdvertisedLimitsScenario.cpp
     Scenarios/PixelStoreSweepScenario.cpp
@@ -63,20 +69,42 @@ add_executable(MobileGLIntegrationTest
     Scenarios/DepthStencilReadbackMatrixScenario.cpp
     Scenarios/DepthStencilReadbackAttachmentShapeScenario.cpp
     Scenarios/ClipDistanceScenario.cpp
+    Scenarios/ViewportArrayScenario.cpp
     Scenarios/SsboArrayLengthScenario.cpp
     Scenarios/DoublePrecisionScenario.cpp
     Scenarios/UniformInitializerScenario.cpp
     Scenarios/SwizzleAccessRoutineScenario.cpp
+    Scenarios/IterationRPFirstReductionScenario.cpp
+    Scenarios/IterationRPProgram203Scenario.cpp
+    Scenarios/IterationRPScratchFixScenario.cpp
     Scenarios/ProgramPipelineScenario.cpp
     Scenarios/ImageLoadStoreSsoScenario.cpp
     Scenarios/ImageTargetKindScenario.cpp
+    Scenarios/ImageFormatQualifierScenario.cpp
+    Scenarios/NonCoreImageFormatScenario.cpp
+    Scenarios/ImageSizeAfterRespecScenario.cpp
     Scenarios/SsboDeclarationFormScenario.cpp
     Scenarios/Glsl420DeclarationScenario.cpp
+    Scenarios/IoBlockNameCollisionScenario.cpp
+    Scenarios/TessellationDrawModeScenario.cpp
+    Scenarios/GeometryDrawModeScenario.cpp
+    Scenarios/PostLinkAttachScenario.cpp
+    Scenarios/FormatlessImageBakeScenario.cpp
     Scenarios/FragmentOutputArrayIndexScenario.cpp
     Scenarios/BufferTextureScenario.cpp
     Scenarios/VertexAttribBindingScenario.cpp
     Scenarios/XfbCaptureBufferReuseScenario.cpp
+    Scenarios/XfbPrimitiveQueryScenario.cpp
     Scenarios/VertexArrayEnableDisableScenario.cpp
+    Scenarios/CopyImageLevelRangeScenario.cpp
+    Scenarios/CopyImageLayeredScenario.cpp
+    Scenarios/PackedWordReadbackScenario.cpp
+    Scenarios/LayeredAttachmentBarrierScenario.cpp
+    Scenarios/LayeredTextureReadbackScenario.cpp
+    Scenarios/AtomicCounterScenario.cpp
+    Scenarios/SsboArrayDynamicIndexScenario.cpp
+    Scenarios/StorageBufferRegrowScenario.cpp
+    Scenarios/RelinkStageSetScenario.cpp
 )
 
 target_include_directories(MobileGLIntegrationTest PRIVATE
@@ -87,9 +115,20 @@ target_include_directories(MobileGLIntegrationTest PRIVATE
 # gtest, not gtest_main: Main.cpp installs the harness banner itself.
 target_link_libraries(MobileGLIntegrationTest PRIVATE
     GTest::gtest
-    MobileGL_s
+    ${MGL_ITEST_MOBILEGL_TARGET}
 )
 
+if (ANDROID)
+    find_library(MGL_ITEST_ANDROID_LIBRARY android REQUIRED)
+    find_library(MGL_ITEST_LOG_LIBRARY log REQUIRED)
+    find_library(MGL_ITEST_MEDIANDK_LIBRARY mediandk REQUIRED)
+    target_link_libraries(MobileGLIntegrationTest PRIVATE
+        ${MGL_ITEST_ANDROID_LIBRARY}
+        ${MGL_ITEST_LOG_LIBRARY}
+        ${MGL_ITEST_MEDIANDK_LIBRARY}
+    )
+endif()
+
 if (MSVC)
     # Same reason as MG_Test/Backend/DirectVulkan: the GLES headers declare gl*
     # as dllimport on Windows, so the in-library GL entry-point definitions only
@@ -98,6 +137,10 @@ if (MSVC)
 endif()
 target_compile_definitions(MobileGLIntegrationTest PRIVATE -DNOMINMAX)
 
+if (ANDROID)
+    return()
+endif()
+
 # --- ctest wiring --------------------------------------------------------
 # A bare libEGL on a glvnd box resolves to whatever vendor comes first, which is
 # usually Mesa/llvmpipe - a software rasteriser silently replacing the GPU under
@@ -218,6 +261,19 @@ endif()
 set(MGL_ITEST_VULKAN_ENV ${MGL_ITEST_COMMON_ENV})
 if (MOBILEGL_ITEST_VK_ICD)
     list(APPEND MGL_ITEST_VULKAN_ENV "VK_ICD_FILENAMES=${MOBILEGL_ITEST_VK_ICD}")
+    # The three iterationRP repairs are tri-state quirks that default to device
+    # auto-detection, and lavapipe is not on any auto list - so on lavapipe the
+    # iterationRP scenarios run unrepaired and Program 203 misses its golden
+    # output. CI's integration-gpu job exports these three by hand; pinning them
+    # to the ICD instead means a local `ctest -L integration-gpu` measures the
+    # same thing the gate does, with no environment to remember.
+    if (MOBILEGL_ITEST_VK_ICD MATCHES "lvp_icd|lavapipe")
+        message(STATUS "Integration tests: lavapipe ICD - forcing the iterationRP repairs on")
+        list(APPEND MGL_ITEST_VULKAN_ENV
+            "MOBILEGL_FIX_ITERATIONRP_SUBGROUP_SCRATCH=1"
+            "MOBILEGL_DERIVE_NUM_SUBGROUPS=1"
+            "MOBILEGL_ITERATIONRP_FIX_BARRIER=1")
+    endif()
 endif()
 
 # The ENVIRONMENT test property is itself a `;`-list, and gtest_discover_tests

MobileGL/MG_IntegrationTest/Harness/HeadlessGL.cpp

@@ -15,6 +15,16 @@
 #include <ostream>
 #include <sstream>
 
+#if defined(_WIN32)
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#elif defined(__ANDROID__)
+#include <android/hardware_buffer.h>
+#include <android/native_window.h>
+#include <media/NdkImage.h>
+#include <media/NdkImageReader.h>
+#endif
+
 // MobileGL's own headers, in the order MobileGL/Includes.h uses them: GL/gl.h
 // first, then glcorearb.h for the 3.x+ entry points. This binary links
 // MobileGL_s, so every gl*/egl* below binds to MobileGL's implementation, not
@@ -32,7 +42,7 @@
 // the only construction that is actually predictive here: MobileGL ABORTS
 // (MOBILEGL_ASSERT -> SIGTRAP) rather than returning an error on an unusable
 // platform, so nothing the parent can call in-process is allowed to be wrong.
-#if !defined(_WIN32) && !defined(__APPLE__) && __has_include(<sys/wait.h>)
+#if !defined(_WIN32) && !defined(__APPLE__) && !defined(__ANDROID__) && __has_include(<sys/wait.h>)
 #define MGITEST_HAVE_FORK_PREFLIGHT 1
 #include <csignal>
 #include <ctime>
@@ -53,6 +63,83 @@ namespace MGITest {
         constexpr int kSurfaceWidth = 128;
         constexpr int kSurfaceHeight = 96;
 
+#if defined(_WIN32)
+        HWND g_testWindow = nullptr;
+
+        HWND CreateTestWindow() {
+            static const wchar_t* const kClassName = L"MobileGLIntegrationTestWindow";
+            static bool registered = false;
+            if (!registered) {
+                WNDCLASSW windowClass{};
+                windowClass.lpfnWndProc = DefWindowProcW;
+                windowClass.hInstance = GetModuleHandleW(nullptr);
+                windowClass.lpszClassName = kClassName;
+                if (RegisterClassW(&windowClass) == 0 && GetLastError() != ERROR_CLASS_ALREADY_EXISTS) {
+                    return nullptr;
+                }
+                registered = true;
+            }
+            return CreateWindowExW(0, kClassName, L"MobileGL Integration Test", WS_OVERLAPPEDWINDOW,
+                                   CW_USEDEFAULT, CW_USEDEFAULT, kSurfaceWidth, kSurfaceHeight, nullptr, nullptr,
+                                   GetModuleHandleW(nullptr), nullptr);
+        }
+#elif defined(__ANDROID__)
+        AImageReader* g_imageReader = nullptr;
+        ANativeWindow* g_imageReaderWindow = nullptr;
+
+        void DrainImageReader(void*, AImageReader* reader) {
+            AImage* image = nullptr;
+            if (AImageReader_acquireNextImage(reader, &image) == AMEDIA_OK && image != nullptr) {
+                AImage_delete(image);
+            }
+        }
+
+        bool CreateImageReaderWindow() {
+            if (g_imageReaderWindow != nullptr) return true;
+            constexpr int kMaxImages = 4;
+            const media_status_t status = AImageReader_newWithUsage(
+                kSurfaceWidth, kSurfaceHeight, AIMAGE_FORMAT_RGBA_8888,
+                AHARDWAREBUFFER_USAGE_GPU_SAMPLED_IMAGE | AHARDWAREBUFFER_USAGE_GPU_COLOR_OUTPUT,
+                kMaxImages, &g_imageReader);
+            if (status != AMEDIA_OK || g_imageReader == nullptr) return false;
+
+            AImageReader_ImageListener listener = {nullptr, DrainImageReader};
+            AImageReader_setImageListener(g_imageReader, &listener);
+            if (AImageReader_getWindow(g_imageReader, &g_imageReaderWindow) != AMEDIA_OK ||
+                g_imageReaderWindow == nullptr) {
+                AImageReader_setImageListener(g_imageReader, nullptr);
+                AImageReader_delete(g_imageReader);
+                g_imageReader = nullptr;
+                return false;
+            }
+            ANativeWindow_acquire(g_imageReaderWindow);
+            return true;
+        }
+
+        void DestroyImageReaderWindow() {
+            if (g_imageReaderWindow != nullptr) {
+                ANativeWindow_release(g_imageReaderWindow);
+                g_imageReaderWindow = nullptr;
+            }
+            if (g_imageReader != nullptr) {
+                AImageReader_setImageListener(g_imageReader, nullptr);
+                AImageReader_delete(g_imageReader);
+                g_imageReader = nullptr;
+            }
+        }
+#endif
+
+        bool UseWindowSurface() {
+#if defined(_WIN32)
+            const char* value = std::getenv("MOBILEGL_ITEST_WINDOW_SURFACE");
+            return value != nullptr && value[0] != '\0' && std::strcmp(value, "0") != 0;
+#elif defined(__ANDROID__)
+            return true;
+#else
+            return false;
+#endif
+        }
+
         std::string EnvOr(const char* name, const char* fallback) {
             const char* value = std::getenv(name);
             return (value != nullptr && value[0] != '\0') ? std::string(value) : std::string(fallback);
@@ -87,10 +174,10 @@ namespace MGITest {
         // callers). surfaceless is the platform with no window-system dependency at
         // all; the surface this file then creates is still a pbuffer, which every
         // platform supports and which the amendment to this rule requires as the
-        // fallback shape. DISPLAY/WAYLAND_DISPLAY are cleared as well so that a
+        // fallback shape on desktop. Android instead supplies an AImageReader
+        // ANativeWindow. DISPLAY/WAYLAND_DISPLAY are cleared as well so that a
         // driver that consults them directly cannot reintroduce the dependency
-        // behind EGL's back. Desktop-only file: MG_IntegrationTest never builds
-        // for Android, so no device path is affected.
+        // behind EGL's back.
         void EnsureHeadlessPlatform() {
 #if defined(__linux__) && !defined(__ANDROID__)
             static bool done = false;
@@ -134,8 +221,9 @@ namespace MGITest {
                 return 3;
             }
 
+            const bool useWindowSurface = UseWindowSurface();
             const EGLint configAttribs[] = {EGL_SURFACE_TYPE,
-                                            EGL_PBUFFER_BIT,
+                                            useWindowSurface ? EGL_WINDOW_BIT : EGL_PBUFFER_BIT,
                                             EGL_RED_SIZE,
                                             8,
                                             EGL_GREEN_SIZE,
@@ -152,7 +240,9 @@ namespace MGITest {
             EGLConfig config = nullptr;
             EGLint configCount = 0;
             if (eglChooseConfig(display, configAttribs, &config, 1, &configCount) != EGL_TRUE || configCount < 1) {
-                outReason = WithEglError("eglChooseConfig found no pbuffer-capable RGBA8/D24 config");
+                outReason = WithEglError(useWindowSurface
+                                             ? "eglChooseConfig found no window-capable RGBA8/D24 config"
+                                             : "eglChooseConfig found no pbuffer-capable RGBA8/D24 config");
                 return 4;
             }
 
@@ -166,10 +256,32 @@ namespace MGITest {
                 return 5;
             }
 
-            const EGLint pbufferAttribs[] = {EGL_WIDTH, kSurfaceWidth, EGL_HEIGHT, kSurfaceHeight, EGL_NONE};
-            EGLSurface surface = eglCreatePbufferSurface(display, config, pbufferAttribs);
+            EGLSurface surface = EGL_NO_SURFACE;
+            if (useWindowSurface) {
+#if defined(_WIN32)
+                if (g_testWindow == nullptr) g_testWindow = CreateTestWindow();
+                if (g_testWindow == nullptr) {
+                    outReason = "failed to create the Windows integration-test window";
+                    return 6;
+                }
+                surface = eglCreateWindowSurface(display, config, g_testWindow, nullptr);
+#elif defined(__ANDROID__)
+                if (!CreateImageReaderWindow()) {
+                    outReason = "failed to create the Android AImageReader integration-test window";
+                    return 6;
+                }
+                surface = eglCreateWindowSurface(display, config, g_imageReaderWindow, nullptr);
+#endif
+            } else {
+                const EGLint pbufferAttribs[] = {EGL_WIDTH, kSurfaceWidth, EGL_HEIGHT, kSurfaceHeight, EGL_NONE};
+                surface = eglCreatePbufferSurface(display, config, pbufferAttribs);
+            }
             if (surface == EGL_NO_SURFACE) {
-                outReason = WithEglError("eglCreatePbufferSurface failed");
+#if defined(__ANDROID__)
+                DestroyImageReaderWindow();
+#endif
+                outReason = WithEglError(useWindowSurface ? "eglCreateWindowSurface failed"
+                                                         : "eglCreatePbufferSurface failed");
                 return 6;
             }
             // The step that brings the whole backend up (DirectVulkan creates its
@@ -491,6 +603,14 @@ namespace MGITest {
         if (m_context != nullptr) eglDestroyContext(display, static_cast<EGLContext>(m_context));
         if (m_surface != nullptr) eglDestroySurface(display, static_cast<EGLSurface>(m_surface));
         eglTerminate(display);
+#if defined(_WIN32)
+        if (g_testWindow != nullptr) {
+            DestroyWindow(g_testWindow);
+            g_testWindow = nullptr;
+        }
+#elif defined(__ANDROID__)
+        DestroyImageReaderWindow();
+#endif
         m_context = nullptr;
         m_surface = nullptr;
         m_display = nullptr;

MobileGL/MG_IntegrationTest/Harness/HeadlessGL.h

@@ -14,11 +14,11 @@
 // inspects backend state - both bugs this module pins were invisible to
 // state-level assertions and visible only in pixels.
 //
-// Headless by construction, following MG_Benchmark/Driver/DriverBench.c: an EGL
-// context on a PBUFFER surface. No window, no window manager, no human. Unlike
-// DriverBench the scenarios do draw to the DEFAULT framebuffer (that is where
-// the Y-flip lives) and do call eglSwapBuffers (that is the frame boundary the
-// cross-frame scenarios need to be real).
+// Headless by construction: desktop uses an EGL pbuffer and Android uses an
+// AImageReader-backed ANativeWindow that needs no Activity. No window manager,
+// no human. Unlike DriverBench the scenarios do draw to the DEFAULT framebuffer
+// (that is where the Y-flip lives) and do call eglSwapBuffers (that is the frame
+// boundary the cross-frame scenarios need to be real).
 //
 // One process is one backend: MOBILEGL_BACKEND_TYPE is latched at
 // initialization, so the CMake wiring runs this binary once per backend rather

MobileGL/MG_IntegrationTest/Main.cpp

@@ -31,8 +31,14 @@ namespace {
                 // silently bound to a workstation's window system is a different
                 // run from CI's and must be visible as one in the log.
                 const char* eglPlatform = std::getenv("EGL_PLATFORM");
-                std::fprintf(stderr, "  renderer: %s\n  surface:  %dx%d pbuffer (headless, EGL_PLATFORM=%s)\n",
+#if defined(__ANDROID__)
+                constexpr const char* surfaceKind = "AImageReader window";
+#else
+                constexpr const char* surfaceKind = "pbuffer";
+#endif
+                std::fprintf(stderr, "  renderer: %s\n  surface:  %dx%d %s (headless, EGL_PLATFORM=%s)\n",
                              gl.RendererString().c_str(), gl.Width(), gl.Height(),
+                             surfaceKind,
                              eglPlatform != nullptr ? eglPlatform : "<unset>");
             } else if (MGITest::RequireGpu()) {
                 std::fprintf(stderr,

MobileGL/MG_IntegrationTest/Scenarios/AdvertisedLimitsScenario.cpp

@@ -199,5 +199,61 @@ namespace MGITest {
                    "derived component limits are computed in";
         }
 
+        // ARB_viewport_array's own limits. They are advertised from three different places -
+        // GL_MAX_VIEWPORTS from the frontend's indexed state width, the bounds range and the
+        // subpixel bits from the backend caps table - and each backend fills that table from a
+        // different source, so all three are checked on both lanes.
+        //
+        // GL_VIEWPORT_BOUNDS_RANGE is the one that shipped wrong: GLES has no such query, the
+        // DirectGLES loader's glGetFloatv(GL_VIEWPORT_BOUNDS_RANGE) therefore raised
+        // GL_INVALID_ENUM and left the probe's zero-initialized array in place, and MobileGL
+        // advertised [0, 0] - a range that admits no viewport origin at all, and the check that
+        // kept KHR-GL43.viewport_array.queries red on Espryt after the indexed-state work.
+        TEST_F(AdvertisedLimitsScenario, ViewportArrayLimitsMeetTheirGL43Floors) {
+            GLint maxViewports = -1;
+            glGetIntegerv(GL_MAX_VIEWPORTS, &maxViewports);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            EXPECT_GE(maxViewports, 16) << "GL 4.3 core table 23.53 sets the MAX_VIEWPORTS minimum at 16";
+            EXPECT_LE(maxViewports, 256) << "one viewport rectangle of indexed state is allocated per advertised "
+                                            "viewport, and the CTS sizes its arrays off this number";
+
+            GLfloat boundsRange[2] = {1.0f, -1.0f};
+            glGetFloatv(GL_VIEWPORT_BOUNDS_RANGE, boundsRange);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            EXPECT_LE(boundsRange[0], -32768.0f)
+                << "GL 4.6 core table 23.60 sets the VIEWPORT_BOUNDS_RANGE minimum at [-32768, 32767]; got ["
+                << boundsRange[0] << ", " << boundsRange[1] << "]";
+            EXPECT_GE(boundsRange[1], 32767.0f)
+                << "GL 4.6 core table 23.60 sets the VIEWPORT_BOUNDS_RANGE minimum at [-32768, 32767]; got ["
+                << boundsRange[0] << ", " << boundsRange[1] << "]";
+
+            // KNOWN INFIDELITY, pinned here rather than hidden. MobileGL reports the driver's own
+            // VIEWPORT_SUBPIXEL_BITS (4 on llvmpipe, i.e. 1/16-pixel viewport precision), but the
+            // float viewport rectangle glViewportIndexedf stores is snapped to integers on its
+            // way to both backends (ComputeGLViewport, DirectGLES SyncRenderState). The STATE
+            // round trip is exact - which is all KHR-GL43.viewport_array.viewport_api checks, and
+            // all this cluster set out to fix - so the gap is in rasterization only: a fractional
+            // viewport origin rasterizes as if it had been rounded. Nothing in the suite or in
+            // Minecraft sets one. Only the spec floor is asserted; tightening this to EQ(0) would
+            // mean advertising no subpixel precision at all, which is a separate decision about a
+            // limit MobileGL currently passes through from the driver.
+            GLint subpixelBits = -1;
+            glGetIntegerv(GL_VIEWPORT_SUBPIXEL_BITS, &subpixelBits);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            EXPECT_GE(subpixelBits, 0) << "GL 4.6 core table 23.60: VIEWPORT_SUBPIXEL_BITS has a minimum of 0, and "
+                                          "a negative value is what a sign-flipped uint32 looks like";
+
+            GLint viewportDims[2] = {-1, -1};
+            glGetIntegerv(GL_MAX_VIEWPORT_DIMS, viewportDims);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            GLint maxRenderbufferSize = -1;
+            glGetIntegerv(GL_MAX_RENDERBUFFER_SIZE, &maxRenderbufferSize);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            // GL 4.6 core 13.6.1: MAX_VIEWPORT_DIMS must be at least as large as the largest
+            // renderable surface, or a full-size framebuffer could not be fully viewported.
+            EXPECT_GE(viewportDims[0], maxRenderbufferSize);
+            EXPECT_GE(viewportDims[1], maxRenderbufferSize);
+        }
+
     } // namespace
 } // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/AtomicCounterScenario.cpp

@@ -0,0 +1,239 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/AtomicCounterScenario.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - ATOMIC COUNTERS, END TO END.
+//
+// GL_ATOMIC_COUNTER_BUFFER does not exist in ES, and glslang does not hand one to a backend
+// either: its Vulkan-relaxed parse rewrites every atomic_uint into a uint member of a
+// synthesized gl_AtomicCounterBlock_<N> STORAGE block. Making counters work therefore means
+// closing two open ends that used to be missing entirely -
+//
+//   * the block's shader-storage binding, which the IO mapper picked at random and which had no
+//     relation to the GL binding point N the application bound its buffer to (and could alias an
+//     SSBO the application binds itself), is moved to a slot reserved at the top of the driver's
+//     range; and
+//   * the buffer bound at GL_ATOMIC_COUNTER_BUFFER point N, which nothing in the ES backend ever
+//     read, is re-issued as a shader-storage binding at that reserved slot.
+//
+// Neither end alone is observable: with only the first the shader increments a block nobody
+// bound a buffer to, with only the second the buffer lands where the shader does not look. The
+// only thing that proves both is the VALUE, so every assertion here reads the counter back.
+//
+// Compute rather than a draw on purpose: the invocation count is exactly what was dispatched,
+// while a fragment stage's is a property of the rasterizer (helper invocations, early depth).
+// Conformance cases behind this: KHR-GL42/GL43.shader_atomic_counters.basic-usage-cs,
+// .advanced-usage-multi-stage and .advanced-usage-draw-update-draw.
+
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        // Two counters share binding 0 at DIFFERENT offsets and a third sits alone on binding 1.
+        // The offsets are what separates "the buffer arrived" from "the buffer arrived and the
+        // block is laid out the way GL says": a lowering that packed the members in declaration
+        // order without honouring `offset` would still pass a single-counter check.
+        constexpr const char* kCounterComputeSource = R"(#version 430 core
+layout(local_size_x = 4) in;
+layout(binding = 0, offset = 0) uniform atomic_uint g_first;
+layout(binding = 0, offset = 4) uniform atomic_uint g_second;
+layout(binding = 1, offset = 0) uniform atomic_uint g_other;
+void main() {
+    atomicCounterIncrement(g_first);
+    atomicCounterIncrement(g_second);
+    atomicCounterIncrement(g_second);
+    atomicCounterIncrement(g_other);
+}
+)";
+
+        constexpr int kLocalSizeX = 4;
+        constexpr int kWorkGroups = 2;
+        constexpr unsigned int kInvocations = kLocalSizeX * kWorkGroups;
+
+        // Deliberately non-zero: the shader adds to whatever the application uploaded, so a seed
+        // that survives is also proof that the buffer's CPU-side contents reached the driver.
+        constexpr unsigned int kSeedFirst = 5;
+        constexpr unsigned int kSeedSecond = 100;
+        constexpr unsigned int kSeedOther = 7;
+
+        class AtomicCounterScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                GLint counters = 0;
+                glGetIntegerv(GL_MAX_COMPUTE_ATOMIC_COUNTERS, &counters);
+                GLint buffers = 0;
+                glGetIntegerv(GL_MAX_COMPUTE_ATOMIC_COUNTER_BUFFERS, &buffers);
+                if (counters < 3 || buffers < 2) {
+                    GTEST_SKIP() << "GL_MAX_COMPUTE_ATOMIC_COUNTERS is " << counters
+                                 << " and GL_MAX_COMPUTE_ATOMIC_COUNTER_BUFFERS is " << buffers
+                                 << "; this needs 3 and 2";
+                }
+                if (!AtomicCountersAreWired()) {
+                    GTEST_SKIP() << "atomic counter buffers are not wired up on " << Gl().BackendName()
+                                 << " yet: glslang lowers them onto a storage block and that block's descriptor "
+                                 << "is still resolved from the shader-storage binding points";
+                }
+                m_program = CompileComputeProgram(kCounterComputeSource);
+                ASSERT_NE(m_program, 0u) << m_buildLog;
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                glUseProgram(0);
+                if (!m_buffers.empty()) glDeleteBuffers(static_cast<GLsizei>(m_buffers.size()), m_buffers.data());
+                if (m_program != 0) glDeleteProgram(m_program);
+                m_buffers.clear();
+                m_program = 0;
+            }
+
+            // Magma binds the lowered block as an ordinary storage-buffer descriptor resolved
+            // from GL_SHADER_STORAGE_BUFFER point N, so the counter buffer never reaches it. The
+            // frontend half (limits, reflection queries, the link-time offset rules) is
+            // backend-agnostic and is covered by the unit suites; only the VALUE is scoped here.
+            bool AtomicCountersAreWired() const { return Gl().BackendName() != "DirectVulkan"; }
+
+            unsigned int CompileComputeProgram(const char* source) {
+                const GLuint shader = glCreateShader(GL_COMPUTE_SHADER);
+                glShaderSource(shader, 1, &source, nullptr);
+                glCompileShader(shader);
+                GLint compiled = 0;
+                glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
+                if (compiled == GL_FALSE) {
+                    char log[2048] = {};
+                    glGetShaderInfoLog(shader, sizeof(log) - 1, nullptr, log);
+                    m_buildLog = std::string("compute shader did not compile: ") + log;
+                    glDeleteShader(shader);
+                    return 0;
+                }
+                const GLuint program = glCreateProgram();
+                glAttachShader(program, shader);
+                glLinkProgram(program);
+                glDeleteShader(shader);
+                GLint linked = 0;
+                glGetProgramiv(program, GL_LINK_STATUS, &linked);
+                if (linked == GL_FALSE) {
+                    char log[2048] = {};
+                    glGetProgramInfoLog(program, sizeof(log) - 1, nullptr, log);
+                    m_buildLog = std::string("compute program did not link: ") + log;
+                    glDeleteProgram(program);
+                    return 0;
+                }
+                return program;
+            }
+
+            // A counter buffer of `count` uints, seeded and bound to atomic-counter point
+            // `binding`.
+            GLuint MakeCounterBuffer(GLuint binding, const std::vector<unsigned int>& seed) {
+                GLuint buffer = 0;
+                glGenBuffers(1, &buffer);
+                glBindBuffer(GL_ATOMIC_COUNTER_BUFFER, buffer);
+                glBufferData(GL_ATOMIC_COUNTER_BUFFER,
+                             static_cast<GLsizeiptr>(seed.size() * sizeof(unsigned int)), seed.data(),
+                             GL_DYNAMIC_DRAW);
+                glBindBufferBase(GL_ATOMIC_COUNTER_BUFFER, binding, buffer);
+                glBindBuffer(GL_ATOMIC_COUNTER_BUFFER, 0);
+                m_buffers.push_back(buffer);
+                return buffer;
+            }
+
+            std::vector<unsigned int> ReadCounters(GLuint buffer, int count) {
+                std::vector<unsigned int> values(static_cast<std::size_t>(count), 0xDEADBEEFu);
+                glBindBuffer(GL_ATOMIC_COUNTER_BUFFER, buffer);
+                glGetBufferSubData(GL_ATOMIC_COUNTER_BUFFER, 0,
+                                   static_cast<GLsizeiptr>(values.size() * sizeof(unsigned int)), values.data());
+                glBindBuffer(GL_ATOMIC_COUNTER_BUFFER, 0);
+                return values;
+            }
+
+            void Dispatch() {
+                glUseProgram(m_program);
+                glDispatchCompute(kWorkGroups, 1, 1);
+                glMemoryBarrier(GL_ATOMIC_COUNTER_BARRIER_BIT | GL_BUFFER_UPDATE_BARRIER_BIT);
+            }
+
+            unsigned int m_program = 0;
+            std::string m_buildLog;
+            std::vector<GLuint> m_buffers;
+        };
+
+    } // namespace
+
+    // The counter values a dispatch leaves behind, per binding point and per offset within one
+    // binding. Nothing in the ES backend used to touch BufferTarget::AtomicCounter at all, so
+    // before the wiring landed every one of these read back its seed unchanged.
+    TEST_F(AtomicCounterScenario, DispatchIncrementsTheBoundCounterBuffers) {
+        if (!Ready() || IsSkipped()) return;
+
+        const GLuint zero = MakeCounterBuffer(0, {kSeedFirst, kSeedSecond});
+        const GLuint one = MakeCounterBuffer(1, {kSeedOther});
+        ASSERT_EQ(FirstGLError(), 0u) << "binding the counter buffers raised a GL error";
+
+        Dispatch();
+        EXPECT_EQ(FirstGLError(), 0u) << "the dispatch raised a GL error";
+
+        const std::vector<unsigned int> zeroValues = ReadCounters(zero, 2);
+        const std::vector<unsigned int> oneValues = ReadCounters(one, 1);
+        EXPECT_EQ(FirstGLError(), 0u) << "reading the counters back raised a GL error";
+
+        EXPECT_EQ(zeroValues[0], kSeedFirst + kInvocations)
+            << "binding 0 offset 0 read back " << zeroValues[0] << "; " << kSeedFirst
+            << " means the shader's increments never reached the buffer the application bound";
+        EXPECT_EQ(zeroValues[1], kSeedSecond + 2 * kInvocations)
+            << "binding 0 offset 4 read back " << zeroValues[1] << "; the seed means the counter at a NON-ZERO "
+            << "offset was not carried through the lowering, even though offset 0 was";
+        EXPECT_EQ(oneValues[0], kSeedOther + kInvocations)
+            << "binding 1 read back " << oneValues[0] << "; a counter buffer past the first binding point "
+            << "resolves to a different reserved slot and is where an off-by-one shows up";
+    }
+
+    // A second dispatch continues from where the first left off, and a re-seed between them is
+    // visible to the shader. Both halves of the buffer's traffic have to work, in both
+    // directions: the increments are only observable through the readback path, and the re-seed
+    // is only observable if the upload reaches the driver AFTER the buffer has been GPU-written.
+    TEST_F(AtomicCounterScenario, CountersAccumulateAcrossDispatchesAndFollowAReseed) {
+        if (!Ready() || IsSkipped()) return;
+
+        const GLuint zero = MakeCounterBuffer(0, {0u, 0u});
+        MakeCounterBuffer(1, {0u});
+        ASSERT_EQ(FirstGLError(), 0u);
+
+        Dispatch();
+        Dispatch();
+        std::vector<unsigned int> values = ReadCounters(zero, 2);
+        EXPECT_EQ(FirstGLError(), 0u);
+        EXPECT_EQ(values[0], 2 * kInvocations) << "two dispatches did not accumulate";
+        EXPECT_EQ(values[1], 4 * kInvocations) << "two dispatches did not accumulate at offset 4";
+
+        const unsigned int reseed[2] = {1000u, 2000u};
+        glBindBuffer(GL_ATOMIC_COUNTER_BUFFER, zero);
+        glBufferSubData(GL_ATOMIC_COUNTER_BUFFER, 0, sizeof(reseed), reseed);
+        glBindBuffer(GL_ATOMIC_COUNTER_BUFFER, 0);
+        ASSERT_EQ(FirstGLError(), 0u) << "re-seeding the counter buffer raised a GL error";
+
+        Dispatch();
+        values = ReadCounters(zero, 2);
+        EXPECT_EQ(FirstGLError(), 0u);
+        EXPECT_EQ(values[0], reseed[0] + kInvocations) << "the re-seeded value did not reach the shader";
+        EXPECT_EQ(values[1], reseed[1] + 2 * kInvocations) << "the re-seeded value at offset 4 did not reach the shader";
+    }
+
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/BufferTextureScenario.cpp

@@ -299,4 +299,99 @@ void main() {
         EXPECT_EQ(FirstGLError(), 0u);
     }
 
+    // glGetTexLevelParameter used to refuse EVERY pname on a buffer texture: WIDTH/HEIGHT/DEPTH
+    // fell out of a mipmap-only switch as GL_INVALID_OPERATION, and GL_TEXTURE_BUFFER_SIZE /
+    // GL_TEXTURE_BUFFER_OFFSET were not in the switch at all, so they came back GL_INVALID_ENUM.
+    // KHR-GL43.texture_buffer wraps both queries in GLU_EXPECT_NO_ERROR, so the error alone fails
+    // the case before any value is compared.
+    //
+    // The two halves report DIFFERENT units and only one of them is clamped, which is the thing
+    // easiest to get backwards: WIDTH is a TEXEL count clamped to GL_MAX_TEXTURE_BUFFER_SIZE,
+    // BUFFER_SIZE is the range in basic machine units exactly as it was given.
+    TEST_F(BufferTextureScenario, LevelQueriesDescribeTheAttachedBufferRange) {
+        if (!Ready()) return;
+        FirstGLError();
+
+        GLint offsetAlignment = 1;
+        glGetIntegerv(GL_TEXTURE_BUFFER_OFFSET_ALIGNMENT, &offsetAlignment);
+        if (offsetAlignment < 1) offsetAlignment = 1;
+        GLint maxTexels = 0;
+        glGetIntegerv(GL_MAX_TEXTURE_BUFFER_SIZE, &maxTexels);
+        ASSERT_EQ(FirstGLError(), 0u);
+        ASSERT_GT(maxTexels, 0) << "an OpenGL 4.x context may not advertise a zero buffer-texture limit";
+
+        constexpr GLint kTexelBytes = 4; // GL_RGBA8
+        const GLsizeiptr rangeOffset = static_cast<GLsizeiptr>(offsetAlignment);
+        const GLsizeiptr rangeBytes = 32 * kTexelBytes;
+        // Deliberately bigger than the range, so a getter that answered out of the BUFFER rather
+        // than out of the texture's window would be caught.
+        const GLsizeiptr bufferBytes = rangeOffset + rangeBytes + 16 * kTexelBytes;
+
+        const std::vector<GLubyte> zeros(static_cast<size_t>(bufferBytes), 0);
+        GLuint buffer = 0;
+        glGenBuffers(1, &buffer);
+        glBindBuffer(GL_TEXTURE_BUFFER, buffer);
+        glBufferData(GL_TEXTURE_BUFFER, bufferBytes, zeros.data(), GL_STATIC_DRAW);
+
+        GLuint texture = 0;
+        glGenTextures(1, &texture);
+        glBindTexture(GL_TEXTURE_BUFFER, texture);
+        glTexBufferRange(GL_TEXTURE_BUFFER, GL_RGBA8, buffer, rangeOffset, rangeBytes);
+        ASSERT_EQ(FirstGLError(), 0u) << "glTexBufferRange(GL_RGBA8) was refused";
+
+        const auto levelQuery = [](GLenum pname) {
+            GLint value = -1;
+            glGetTexLevelParameteriv(GL_TEXTURE_BUFFER, 0, pname, &value);
+            return value;
+        };
+        const auto levelQueryF = [](GLenum pname) {
+            GLfloat value = -1.0f;
+            glGetTexLevelParameterfv(GL_TEXTURE_BUFFER, 0, pname, &value);
+            return value;
+        };
+
+        EXPECT_EQ(levelQuery(GL_TEXTURE_WIDTH), static_cast<GLint>(rangeBytes / kTexelBytes))
+            << "GL_TEXTURE_WIDTH is a texel count over the attached RANGE";
+        EXPECT_EQ(levelQuery(GL_TEXTURE_HEIGHT), 1);
+        EXPECT_EQ(levelQuery(GL_TEXTURE_DEPTH), 1);
+        EXPECT_EQ(levelQuery(GL_TEXTURE_BUFFER_SIZE), static_cast<GLint>(rangeBytes))
+            << "GL_TEXTURE_BUFFER_SIZE reports basic machine units, not texels";
+        EXPECT_EQ(levelQuery(GL_TEXTURE_BUFFER_OFFSET), static_cast<GLint>(rangeOffset));
+        EXPECT_EQ(FirstGLError(), 0u) << "a buffer-texture level query raised an error";
+        EXPECT_LE(levelQuery(GL_TEXTURE_WIDTH), maxTexels)
+            << "GL_TEXTURE_WIDTH must stay clamped to GL_MAX_TEXTURE_BUFFER_SIZE";
+
+        // The float getter is a separate switch and has drifted from the integer one before.
+        EXPECT_FLOAT_EQ(levelQueryF(GL_TEXTURE_WIDTH), static_cast<GLfloat>(rangeBytes / kTexelBytes));
+        EXPECT_FLOAT_EQ(levelQueryF(GL_TEXTURE_HEIGHT), 1.0f);
+        EXPECT_FLOAT_EQ(levelQueryF(GL_TEXTURE_BUFFER_SIZE), static_cast<GLfloat>(rangeBytes));
+        EXPECT_EQ(FirstGLError(), 0u) << "the float form of a buffer-texture level query raised an error";
+
+        // The whole-buffer form follows the buffer's current size instead of freezing a window.
+        glTexBuffer(GL_TEXTURE_BUFFER, GL_RGBA8, buffer);
+        EXPECT_EQ(levelQuery(GL_TEXTURE_BUFFER_OFFSET), 0);
+        EXPECT_EQ(levelQuery(GL_TEXTURE_BUFFER_SIZE), static_cast<GLint>(bufferBytes));
+        EXPECT_EQ(levelQuery(GL_TEXTURE_WIDTH), static_cast<GLint>(bufferBytes / kTexelBytes));
+        EXPECT_EQ(FirstGLError(), 0u);
+
+        // Both buffer pnames belong to buffer textures alone; anything else is INVALID_OPERATION,
+        // the same shape GL_TEXTURE_COMPRESSED_IMAGE_SIZE uses for an uncompressed image.
+        GLuint plainTexture = 0;
+        glGenTextures(1, &plainTexture);
+        glBindTexture(GL_TEXTURE_2D, plainTexture);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 4, 4, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+        EXPECT_EQ(FirstGLError(), 0u);
+        GLint unused = -1;
+        glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_BUFFER_SIZE, &unused);
+        EXPECT_EQ(FirstGLError(), static_cast<unsigned int>(GL_INVALID_OPERATION));
+
+        glBindTexture(GL_TEXTURE_2D, 0);
+        glBindTexture(GL_TEXTURE_BUFFER, 0);
+        glBindBuffer(GL_TEXTURE_BUFFER, 0);
+        glDeleteTextures(1, &plainTexture);
+        glDeleteTextures(1, &texture);
+        glDeleteBuffers(1, &buffer);
+        EXPECT_EQ(FirstGLError(), 0u);
+    }
+
 } // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/ClipDistanceScenario.cpp

@@ -151,6 +151,18 @@ void main() { fragColor = vec4(0.0, 1.0, 0.0, 1.0); }
                 glReadPixels(x, y, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, out);
             }
 
+            // GL_MAX_CLIP_DISTANCES is a real backend answer, not a constant: DirectGLES reports
+            // 0 on a driver without GL_EXT_clip_cull_distance, and DirectVulkan reports 0 without
+            // the shaderClipDistance device feature. On such a stack the shader above cannot
+            // compile - and MUST not, because declaring a clip distance the backend cannot host
+            // is exactly what used to link cleanly and then render nothing. Skip rather than
+            // fail: there is no clipping to assert about.
+            static bool BackendHostsTwoClipDistances() {
+                GLint maxClipDistances = 0;
+                glGetIntegerv(GL_MAX_CLIP_DISTANCES, &maxClipDistances);
+                return maxClipDistances >= 2;
+            }
+
             // Never assume the eight start disabled - see the header note about
             // XfbAfterClipDistanceScenario leaving one on for the rest of the process.
             static void DisableEveryClipDistance() {
@@ -229,6 +241,9 @@ void main() { fragColor = vec4(0.0, 1.0, 0.0, 1.0); }
     // The claim: an enabled clip distance removes the fragments where it is negative.
     TEST_F(ClipDistanceScenario, AnEnabledClipDistanceRemovesTheNegativeHalf) {
         if (!Ready()) return;
+        if (!BackendHostsTwoClipDistances()) {
+            GTEST_SKIP() << "this backend advertises no clip distances, so there is nothing to clip with";
+        }
         HeadlessGL& gl = Gl();
         const int width = gl.Width();
         const int height = gl.Height();
@@ -280,6 +295,9 @@ void main() { fragColor = vec4(0.0, 1.0, 0.0, 1.0); }
     // draw simply failed - would pass the case above.
     TEST_F(ClipDistanceScenario, ADisabledClipDistanceRemovesNothing) {
         if (!Ready()) return;
+        if (!BackendHostsTwoClipDistances()) {
+            GTEST_SKIP() << "this backend advertises no clip distances, so there is nothing to clip with";
+        }
         HeadlessGL& gl = Gl();
         const int width = gl.Width();
         const int height = gl.Height();
@@ -329,6 +347,9 @@ void main() { fragColor = vec4(0.0, 1.0, 0.0, 1.0); }
     // passes both cases above and fails this one.
     TEST_F(ClipDistanceScenario, TheEnablesAreIndependentPerDistance) {
         if (!Ready()) return;
+        if (!BackendHostsTwoClipDistances()) {
+            GTEST_SKIP() << "this backend advertises no clip distances, so there is nothing to clip with";
+        }
         HeadlessGL& gl = Gl();
         const int width = gl.Width();
         const int height = gl.Height();

MobileGL/MG_IntegrationTest/Scenarios/CopyImageLayeredScenario.cpp

@@ -0,0 +1,331 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/CopyImageLayeredScenario.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - glCopyImageSubData MOVES EVERY SLICE IT WAS ASKED FOR, NOT JUST SLICE 0.
+//
+// KHR-GL43.copy_image.functional_* copies a whole 12-layer region in one call whenever both
+// endpoints are layered, i.e. for the four target pairs 2d_array->2d_array, 2d_array->3d,
+// 3d->2d_array and 3d->3d. DirectVulkan built its VkImageCopy with baseArrayLayer 0, layerCount 1
+// and srcOffset.z 0 no matter what the call asked for, so slice 0 landed correctly and slices 1..N
+// were never written - 64 conformance cases (16 compatible format pairs x those 4 pairs) failing
+// with "first mismatch at [x, y, 1]", the first texel of the first slice the copy skipped.
+//
+// The reason one hardcode covered both shapes wrongly is that GL states a layered copy ONE way -
+// srcZ/dstZ and srcDepth - while Vulkan states it two ways and picks by image type:
+//
+//   GL_TEXTURE_3D       -> VK_IMAGE_TYPE_3D: slices are z, so srcOffset.z/dstOffset.z select them
+//                          and extent.depth counts them; the layer range must stay (0, 1).
+//   GL_TEXTURE_2D_ARRAY -> VK_IMAGE_TYPE_2D: slices are array layers, so baseArrayLayer selects
+//                          them and layerCount counts them; offset.z stays 0.
+//
+// A mixed pair is legal (maintenance1, core in Vulkan 1.1) but only when the counts correspond:
+// the 3D side's extent.depth has to equal the array side's layerCount. So the four pairs below are
+// four DIFFERENT VkImageCopy shapes, not one shape with different arguments, which is why one
+// scenario per pair is the coverage that matters here.
+//
+// Every case also asserts the slices OUTSIDE the copied range still hold their fill. A backend
+// that "fixed" the miss by copying the whole image regardless of srcZ/srcDepth would pass a
+// slices-landed check and fail this one.
+//
+// The verification path is an FBO attachment per slice plus glReadPixels, not glGetTexImage: it is
+// the readback both backends share, and glFramebufferTextureLayer names an array layer and a 3D
+// slice through the same call, so the two texture kinds are read back identically.
+//
+// DirectGLES is the control - it forwards to the driver's own glCopyImageSubData - so a failure on
+// both backends means the scenario is wrong, and a failure on DirectVulkan alone means Magma is.
+
+#include <array>
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        constexpr int kWidth = 4;
+        constexpr int kHeight = 4;
+        // Six is enough for a copy that starts and ends away from both edges of both endpoints
+        // while still leaving untouched slices on either side to assert against.
+        constexpr int kSlices = 6;
+
+        struct Rgba8 {
+            GLubyte r = 0, g = 0, b = 0, a = 0;
+
+            bool operator==(const Rgba8& other) const {
+                return r == other.r && g == other.g && b == other.b && a == other.a;
+            }
+        };
+
+        std::string Describe(const Rgba8& color) {
+            return "(" + std::to_string(color.r) + ", " + std::to_string(color.g) + ", " + std::to_string(color.b) +
+                   ", " + std::to_string(color.a) + ")";
+        }
+
+        // Per-slice constants, uniform within a slice. A uniform fill is deliberate: the defect is
+        // in which SLICE the copy addresses, and a value that also varied within the slice would
+        // make the assertions depend on the framebuffer row order as well.
+        Rgba8 SourceColor(int slice) {
+            return {static_cast<GLubyte>(10 + slice * 20), static_cast<GLubyte>(40 + slice * 10),
+                    static_cast<GLubyte>(200 - slice * 15), 255};
+        }
+
+        Rgba8 DestinationFill(int slice) {
+            return {static_cast<GLubyte>(3 + slice), static_cast<GLubyte>(250 - slice * 7),
+                    static_cast<GLubyte>(120 + slice * 5), 255};
+        }
+
+        class CopyImageLayeredScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                if (!CopyImageSubDataUsable()) {
+                    GTEST_SKIP() << "glCopyImageSubData is unavailable on backend " << Gl().BackendName();
+                }
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                for (const GLuint texture : m_textures) {
+                    glDeleteTextures(1, &texture);
+                }
+                m_textures.clear();
+                if (m_fbo != 0) {
+                    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+                    glDeleteFramebuffers(1, &m_fbo);
+                    m_fbo = 0;
+                }
+            }
+
+            // A trivial 1x1x1 array-to-array copy: it exercises the entry point without depending
+            // on any of the behaviour under test, so a driver (or a backend function table) that
+            // simply does not have the call skips instead of failing every case below.
+            bool CopyImageSubDataUsable() {
+                GLuint probe[2] = {0, 0};
+                glGenTextures(2, probe);
+                for (const GLuint texture : probe) {
+                    glBindTexture(GL_TEXTURE_2D_ARRAY, texture);
+                    glTexStorage3D(GL_TEXTURE_2D_ARRAY, 1, GL_RGBA8, 1, 1, 1);
+                }
+                glBindTexture(GL_TEXTURE_2D_ARRAY, 0);
+                while (glGetError() != GL_NO_ERROR) {
+                }
+                glCopyImageSubData(probe[0], GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0, probe[1], GL_TEXTURE_2D_ARRAY, 0, 0, 0,
+                                   0, 1, 1, 1);
+                const bool usable = glGetError() == GL_NO_ERROR;
+                glDeleteTextures(2, probe);
+                return usable;
+            }
+
+            // `target` is GL_TEXTURE_2D_ARRAY or GL_TEXTURE_3D; both take glTexStorage3D and
+            // glTexSubImage3D with the slice on the same axis, which is the whole reason GL can
+            // copy between them. `levels` > 1 puts a real mip chain behind the level the copy
+            // names, so the level's own extent - a 3D level's depth included - has to be resolved
+            // rather than assumed to be the image's.
+            GLuint MakeTexture(GLenum target, int levels, Rgba8 (*colorForSlice)(int)) {
+                GLuint texture = 0;
+                glGenTextures(1, &texture);
+                m_textures.push_back(texture);
+                glBindTexture(target, texture);
+                glTexStorage3D(target, levels, GL_RGBA8, kWidth << (levels - 1), kHeight << (levels - 1),
+                               target == GL_TEXTURE_3D ? (kSlices << (levels - 1)) : kSlices);
+                glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+                glTexParameteri(target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+
+                // Fill every level, so nothing below can pass by reading a level that was never
+                // written and happened to hold the expected bytes.
+                for (int level = 0; level < levels; ++level) {
+                    const int levelWidth = kWidth << (levels - 1 - level);
+                    const int levelHeight = kHeight << (levels - 1 - level);
+                    const int levelSlices =
+                        target == GL_TEXTURE_3D ? (kSlices << (levels - 1 - level)) : kSlices;
+                    for (int slice = 0; slice < levelSlices; ++slice) {
+                        const Rgba8 color = colorForSlice(slice % kSlices);
+                        std::vector<Rgba8> texels(static_cast<size_t>(levelWidth) * levelHeight, color);
+                        glTexSubImage3D(target, level, 0, 0, slice, levelWidth, levelHeight, 1, GL_RGBA,
+                                        GL_UNSIGNED_BYTE, texels.data());
+                    }
+                }
+                glBindTexture(target, 0);
+                return texture;
+            }
+
+            // One slice of one level, through an FBO attachment. glFramebufferTextureLayer takes an
+            // array layer and a 3D slice through the same argument, so both targets read back the
+            // same way.
+            Rgba8 ReadSlice(GLuint texture, int level, int slice, int width, int height) {
+                if (m_fbo == 0) {
+                    glGenFramebuffers(1, &m_fbo);
+                }
+                glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
+                glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, texture, level, slice);
+                EXPECT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE))
+                    << "slice " << slice << " of level " << level << " is not attachable";
+                std::vector<Rgba8> pixels(static_cast<size_t>(width) * height, Rgba8{});
+                glReadBuffer(GL_COLOR_ATTACHMENT0);
+                glPixelStorei(GL_PACK_ALIGNMENT, 1);
+                glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());
+                glBindFramebuffer(GL_FRAMEBUFFER, 0);
+
+                // The fill is uniform within a slice, so any disagreement between texels is itself
+                // a failure - reported here rather than silently reduced to pixels[0].
+                for (size_t i = 1; i < pixels.size(); ++i) {
+                    EXPECT_TRUE(pixels[i] == pixels[0])
+                        << "slice " << slice << " of level " << level << " is not uniform: texel 0 is "
+                        << Describe(pixels[0]) << ", texel " << i << " is " << Describe(pixels[i]);
+                }
+                return pixels[0];
+            }
+
+            // The assertion every case ends with: slices inside [dstZ, dstZ + depth) hold the
+            // source slice they were fed, and every slice outside it still holds its own fill.
+            void ExpectCopied(GLuint destination, int level, int width, int height, int sliceCount, int srcZ,
+                              int dstZ, int depth, const char* what) {
+                for (int slice = 0; slice < sliceCount; ++slice) {
+                    const bool inRange = slice >= dstZ && slice < dstZ + depth;
+                    const Rgba8 expected =
+                        inRange ? SourceColor(srcZ + (slice - dstZ)) : DestinationFill(slice);
+                    const Rgba8 actual = ReadSlice(destination, level, slice, width, height);
+                    EXPECT_TRUE(actual == expected)
+                        << what << ": destination slice " << slice << (inRange ? " (copied)" : " (untouched)")
+                        << " is " << Describe(actual) << ", expected " << Describe(expected);
+                }
+            }
+
+            std::vector<GLuint> m_textures;
+            GLuint m_fbo = 0;
+        };
+
+        // 2d_array -> 2d_array. Both endpoints put the slices on the layer axis, so BOTH layer
+        // counts carry the depth and extent.depth must stay 1.
+        TEST_F(CopyImageLayeredScenario, ArrayToArrayCopiesEverySlice) {
+            if (!Ready() || IsSkipped()) return;
+
+            const GLuint source = MakeTexture(GL_TEXTURE_2D_ARRAY, 1, SourceColor);
+            const GLuint destination = MakeTexture(GL_TEXTURE_2D_ARRAY, 1, DestinationFill);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "texture setup failed";
+
+            glCopyImageSubData(source, GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0, destination, GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0,
+                               kWidth, kHeight, kSlices);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "glCopyImageSubData raised an error";
+
+            ExpectCopied(destination, 0, kWidth, kHeight, kSlices, 0, 0, kSlices, "array->array, all slices");
+        }
+
+        // The same pair with the layer ranges offset differently on the two sides: the shape that
+        // separates "copies more than slice 0" from "copies the RIGHT slices". A backend that read
+        // the source range but wrote from layer 0 (or vice versa) passes the case above.
+        TEST_F(CopyImageLayeredScenario, ArrayToArrayHonoursDifferentLayerOffsets) {
+            if (!Ready() || IsSkipped()) return;
+
+            const GLuint source = MakeTexture(GL_TEXTURE_2D_ARRAY, 1, SourceColor);
+            const GLuint destination = MakeTexture(GL_TEXTURE_2D_ARRAY, 1, DestinationFill);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "texture setup failed";
+
+            constexpr int kSrcZ = 3;
+            constexpr int kDstZ = 1;
+            constexpr int kDepth = 2;
+            glCopyImageSubData(source, GL_TEXTURE_2D_ARRAY, 0, 0, 0, kSrcZ, destination, GL_TEXTURE_2D_ARRAY, 0, 0, 0,
+                               kDstZ, kWidth, kHeight, kDepth);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "glCopyImageSubData raised an error";
+
+            ExpectCopied(destination, 0, kWidth, kHeight, kSlices, kSrcZ, kDstZ, kDepth,
+                         "array->array, offset layer ranges");
+        }
+
+        // 3d -> 3d. Neither endpoint has array layers at all: the depth travels on extent.depth and
+        // the offsets on srcOffset.z/dstOffset.z, with both layer counts pinned to 1.
+        TEST_F(CopyImageLayeredScenario, VolumeToVolumeHonoursNonZeroZ) {
+            if (!Ready() || IsSkipped()) return;
+
+            const GLuint source = MakeTexture(GL_TEXTURE_3D, 1, SourceColor);
+            const GLuint destination = MakeTexture(GL_TEXTURE_3D, 1, DestinationFill);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "texture setup failed";
+
+            constexpr int kSrcZ = 1;
+            constexpr int kDstZ = 3;
+            constexpr int kDepth = 3;
+            glCopyImageSubData(source, GL_TEXTURE_3D, 0, 0, 0, kSrcZ, destination, GL_TEXTURE_3D, 0, 0, 0, kDstZ,
+                               kWidth, kHeight, kDepth);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "glCopyImageSubData raised an error";
+
+            ExpectCopied(destination, 0, kWidth, kHeight, kSlices, kSrcZ, kDstZ, kDepth, "3d->3d, non-zero z");
+        }
+
+        // The same pair one mip level down. A 3D level's DEPTH halves with its width and height, so
+        // this is the only case where the slice count the copy may name is not the image's own -
+        // the bound a layered endpoint is checked against has to come from the level.
+        TEST_F(CopyImageLayeredScenario, VolumeToVolumeAtNonZeroMipLevel) {
+            if (!Ready() || IsSkipped()) return;
+
+            const GLuint source = MakeTexture(GL_TEXTURE_3D, 2, SourceColor);
+            const GLuint destination = MakeTexture(GL_TEXTURE_3D, 2, DestinationFill);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "texture setup failed";
+
+            constexpr int kLevel = 1;
+            constexpr int kSrcZ = 2;
+            constexpr int kDstZ = 0;
+            constexpr int kDepth = 4;
+            glCopyImageSubData(source, GL_TEXTURE_3D, kLevel, 0, 0, kSrcZ, destination, GL_TEXTURE_3D, kLevel, 0, 0,
+                               kDstZ, kWidth, kHeight, kDepth);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "glCopyImageSubData raised an error";
+
+            ExpectCopied(destination, kLevel, kWidth, kHeight, kSlices, kSrcZ, kDstZ, kDepth,
+                         "3d->3d at mip level 1");
+        }
+
+        // 2d_array -> 3d. The mixed shape: the source counts its slices as layers, the destination
+        // as depth, and Vulkan requires extent.depth to equal the source's layerCount.
+        TEST_F(CopyImageLayeredScenario, ArrayToVolumeCopiesEverySlice) {
+            if (!Ready() || IsSkipped()) return;
+
+            const GLuint source = MakeTexture(GL_TEXTURE_2D_ARRAY, 1, SourceColor);
+            const GLuint destination = MakeTexture(GL_TEXTURE_3D, 1, DestinationFill);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "texture setup failed";
+
+            constexpr int kSrcZ = 2;
+            constexpr int kDstZ = 1;
+            constexpr int kDepth = 4;
+            glCopyImageSubData(source, GL_TEXTURE_2D_ARRAY, 0, 0, 0, kSrcZ, destination, GL_TEXTURE_3D, 0, 0, 0, kDstZ,
+                               kWidth, kHeight, kDepth);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "glCopyImageSubData raised an error";
+
+            ExpectCopied(destination, 0, kWidth, kHeight, kSlices, kSrcZ, kDstZ, kDepth, "2d_array->3d");
+        }
+
+        // 3d -> 2d_array, the mirror image: the depth now has to reach the DESTINATION's layerCount
+        // while the source states it as extent.depth from a z offset.
+        TEST_F(CopyImageLayeredScenario, VolumeToArrayCopiesEverySlice) {
+            if (!Ready() || IsSkipped()) return;
+
+            const GLuint source = MakeTexture(GL_TEXTURE_3D, 1, SourceColor);
+            const GLuint destination = MakeTexture(GL_TEXTURE_2D_ARRAY, 1, DestinationFill);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "texture setup failed";
+
+            constexpr int kSrcZ = 1;
+            constexpr int kDstZ = 2;
+            constexpr int kDepth = 4;
+            glCopyImageSubData(source, GL_TEXTURE_3D, 0, 0, 0, kSrcZ, destination, GL_TEXTURE_2D_ARRAY, 0, 0, 0, kDstZ,
+                               kWidth, kHeight, kDepth);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "glCopyImageSubData raised an error";
+
+            ExpectCopied(destination, 0, kWidth, kHeight, kSlices, kSrcZ, kDstZ, kDepth, "3d->2d_array");
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/CopyImageLevelRangeScenario.cpp

@@ -0,0 +1,209 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/CopyImageLevelRangeScenario.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// KHR-GL43.copy_image.non_existent_mipmap, and what it cost.
+//
+// The CTS case is a pure negative test: two 16x16 textures that have level 0 and
+// nothing else, and a glCopyImageSubData naming level 1. The answer is
+// GL_INVALID_VALUE (GL 4.6 core 18.3.2 / ARB_copy_image: "srcLevel/dstLevel is not
+// a valid level"). MobileGL's frontend only checked the level against
+// GL_MAX_TEXTURE_SIZE, so level 1 sailed through into the backends, DirectVulkan
+// resolved it into a VkImageCopy subresource on a VkImage that was created with
+// exactly one mip level, and the Adreno driver dereferenced the level it was
+// promised - SIGSEGV inside vkCmdCopyImage, taking the whole glcts process down
+// mid-run. A negative case must never do that.
+//
+// So the level-1-on-a-one-level-texture rejection is the regression proper, and the
+// rest of this file is what keeps the fix honest. A validator that answered
+// GL_INVALID_VALUE to every level would satisfy the regression tests alone, so the
+// scenarios below pin the BOUNDARY rather than the symptom:
+//
+//   * a texture that really does have two levels must accept a copy at level 1,
+//   * the same texture must still reject level 2,
+//   * and a plain level-0 copy must move pixels, which is checked by reading the
+//     destination back rather than by trusting glGetError.
+//
+// Both backends are covered because the fix is in the shared frontend: DirectGLES
+// forwards to the ES glCopyImageSubData (whose own error lands in the ES context,
+// not in MobileGL's, so it never reached the application either) and DirectVulkan
+// records the copy itself.
+
+#include <array>
+#include <cstring>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        constexpr GLsizei kSize = 16;
+
+        struct Rgba8 {
+            GLubyte r, g, b, a;
+            bool operator==(const Rgba8& other) const {
+                return r == other.r && g == other.g && b == other.b && a == other.a;
+            }
+        };
+
+        std::vector<Rgba8> SolidImage(GLsizei width, GLsizei height, Rgba8 color) {
+            return std::vector<Rgba8>(static_cast<std::size_t>(width) * static_cast<std::size_t>(height), color);
+        }
+
+        class CopyImageLevelRangeScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                DrainErrors();
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                DeleteTextures();
+                if (m_fbo != 0) {
+                    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+                    glDeleteFramebuffers(1, &m_fbo);
+                    m_fbo = 0;
+                }
+                DrainErrors();
+                ScenarioTest::TearDown();
+            }
+
+            static void DrainErrors() {
+                for (int i = 0; i < 16 && glGetError() != GL_NO_ERROR; ++i) {
+                }
+            }
+
+            void DeleteTextures() {
+                if (m_src != 0) glDeleteTextures(1, &m_src);
+                if (m_dst != 0) glDeleteTextures(1, &m_dst);
+                m_src = 0;
+                m_dst = 0;
+            }
+
+            // One 16x16 RGBA8 texture with `levelCount` levels defined through
+            // glTexImage2D - the same way the CTS case builds its textures, and
+            // deliberately NOT glTexStorage2D: an immutable allocation would define the
+            // whole chain up front and could not express "level 1 does not exist".
+            GLuint MakeTexture(int levelCount, Rgba8 baseColor) {
+                GLuint texture = 0;
+                glGenTextures(1, &texture);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                for (int level = 0; level < levelCount; ++level) {
+                    const GLsizei extent = kSize >> level;
+                    const std::vector<Rgba8> pixels = SolidImage(extent, extent, baseColor);
+                    glTexImage2D(GL_TEXTURE_2D, level, GL_RGBA8, extent, extent, 0, GL_RGBA, GL_UNSIGNED_BYTE,
+                                 pixels.data());
+                }
+                // What Utils::makeTextureComplete does in the CTS case: the texture is
+                // complete for the levels it actually has, not for a chain it does not.
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, levelCount - 1);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                glBindTexture(GL_TEXTURE_2D, 0);
+                return texture;
+            }
+
+            void MakePair(int levelCount) {
+                DeleteTextures();
+                m_src = MakeTexture(levelCount, Rgba8{11, 22, 33, 255});
+                m_dst = MakeTexture(levelCount, Rgba8{200, 100, 50, 255});
+                ASSERT_EQ(glGetError(), GL_NO_ERROR) << "texture setup with " << levelCount << " level(s)";
+            }
+
+            // The call under test, at whatever levels the caller wants, over a 1x1
+            // region so the region check can never be what rejects it.
+            GLenum CopyAt(GLint srcLevel, GLint dstLevel, GLsizei extent = 1) {
+                DrainErrors();
+                glCopyImageSubData(m_src, GL_TEXTURE_2D, srcLevel, 0, 0, 0, m_dst, GL_TEXTURE_2D, dstLevel, 0, 0, 0,
+                                   extent, extent, 1);
+                const GLenum error = glGetError();
+                // A second pending error would mean the entry point queued more than one,
+                // and the extra would be handed out at an unrelated call site later.
+                EXPECT_EQ(glGetError(), GL_NO_ERROR) << "the copy recorded more than one error";
+                return error;
+            }
+
+            Rgba8 ReadBackDestinationLevel0() {
+                if (m_fbo == 0) glGenFramebuffers(1, &m_fbo);
+                glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
+                glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_dst, 0);
+                const GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
+                if (status != GL_FRAMEBUFFER_COMPLETE) {
+                    ADD_FAILURE() << "readback framebuffer incomplete: " << status;
+                    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+                    return Rgba8{0, 0, 0, 0};
+                }
+                Rgba8 texel{0, 0, 0, 0};
+                glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &texel);
+                glBindFramebuffer(GL_FRAMEBUFFER, 0);
+                return texel;
+            }
+
+            GLuint m_src = 0;
+            GLuint m_dst = 0;
+            GLuint m_fbo = 0;
+        };
+
+        // The regression. Level 1 of a texture that has only level 0 is not a level, and
+        // saying so is the whole job: before the fix this reached DirectVulkan, which
+        // handed mipLevel=1 to vkCmdCopyImage on a one-level VkImage and died inside the
+        // Adreno driver.
+        TEST_F(CopyImageLevelRangeScenario, LevelOneOfASingleLevelTextureIsRejected) {
+            if (!Ready()) GTEST_SKIP();
+            MakePair(1);
+
+            EXPECT_EQ(CopyAt(1, 0), static_cast<GLenum>(GL_INVALID_VALUE)) << "source level 1";
+            EXPECT_EQ(CopyAt(0, 1), static_cast<GLenum>(GL_INVALID_VALUE)) << "destination level 1";
+            EXPECT_EQ(CopyAt(1, 1), static_cast<GLenum>(GL_INVALID_VALUE)) << "both levels 1";
+        }
+
+        // The negative control that makes the test above falsifiable: the same level
+        // index, on textures that genuinely have it, must be accepted. A validator that
+        // rejected every non-zero level would pass the regression test and fail here.
+        TEST_F(CopyImageLevelRangeScenario, LevelOneOfATwoLevelTextureIsAccepted) {
+            if (!Ready()) GTEST_SKIP();
+            MakePair(2);
+
+            EXPECT_EQ(CopyAt(1, 1), static_cast<GLenum>(GL_NO_ERROR));
+        }
+
+        // And the boundary from the other side: two levels means 0 and 1, not 2.
+        TEST_F(CopyImageLevelRangeScenario, LevelTwoOfATwoLevelTextureIsRejected) {
+            if (!Ready()) GTEST_SKIP();
+            MakePair(2);
+
+            EXPECT_EQ(CopyAt(2, 0), static_cast<GLenum>(GL_INVALID_VALUE)) << "source level 2";
+            EXPECT_EQ(CopyAt(0, 2), static_cast<GLenum>(GL_INVALID_VALUE)) << "destination level 2";
+        }
+
+        // Errors alone cannot tell an accepted copy from a silently dropped one, so the
+        // ordinary case is checked by reading the destination back: the copy has to move
+        // the source's texel, not merely decline to complain.
+        TEST_F(CopyImageLevelRangeScenario, AValidLevelZeroCopyStillMovesPixels) {
+            if (!Ready()) GTEST_SKIP();
+            MakePair(1);
+
+            ASSERT_EQ(ReadBackDestinationLevel0(), (Rgba8{200, 100, 50, 255})) << "destination before the copy";
+            EXPECT_EQ(CopyAt(0, 0, kSize), static_cast<GLenum>(GL_NO_ERROR));
+            EXPECT_EQ(ReadBackDestinationLevel0(), (Rgba8{11, 22, 33, 255})) << "destination after the copy";
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/DoublePrecisionScenario.cpp

@@ -6,27 +6,32 @@
 // SPDX-License-Identifier: LGPL-3.0-only
 // End of Source File Header
 //
-// Scenario - GLSL DOUBLES, RUN AT SINGLE PRECISION.
+// Scenario - GLSL DOUBLES, AT WHATEVER PRECISION THE BACKEND CAN GIVE.
 //
 // No mobile GPU has 64-bit floats. Adreno and Mali both report shaderFloat64 == VK_FALSE, so
-// Magma cannot build a module that declares the Float64 capability, and ESSL has no fp64 type
-// at all, so SPIRV-Cross refuses the module outright on Espryt ("FP64 not supported in ES
-// profile") and the program never reaches the driver. MobileGL therefore narrows every 64-bit
-// float in a shader to 32 bits (ShaderTranspiler::DemoteFloat64Pass) rather than declining the
-// shader: `double` compiles and runs everywhere, at float precision.
+// Magma cannot build a module that declares the Float64 capability there, and ESSL has no fp64
+// type at all, so SPIRV-Cross refuses the module outright on Espryt ("FP64 not supported in ES
+// profile") and the program never reaches the driver. On every such backend MobileGL narrows
+// every 64-bit float in a shader to 32 bits (ShaderTranspiler::DemoteFloat64Pass) rather than
+// declining the shader: `double` compiles and runs everywhere, at float precision. Where the
+// backend DOES consume 64-bit floats - lavapipe is the one that does - the narrowing is skipped
+// and the doubles reach the driver whole.
 //
-// The narrowing is only half a contract. The other half is the API side: the global UBO is
-// laid out by reflecting the DEMOTED module, so glUniform*d has to store a float where the
-// shader reads a float, glGetUniform*v has to read one back, and a dmat4's columns are now
-// std140-padded like any other matrix's. Every one of those is a byte offset that fails
-// silently - the uniform simply reads as something else - so the cases below set values
-// through the API and have the SHADER report what it saw.
+// Either way it is only half a contract. The other half is the API side: the global UBO is laid
+// out by reflecting whichever module was produced, so glUniform*d has to store the width the
+// shader reads, glGetUniform*v has to read that width back, and a matrix's columns are
+// std140-padded to a vec4 or a dvec4 to match. Every one of those is a byte offset that fails
+// silently - the uniform simply reads as something else - so the cases below set values through
+// the API and have the SHADER report what it saw.
 //
-// What is deliberately NOT asserted: that the values are exact to double precision. They are
-// not, and cannot be. Every expectation here is the float value of the double that was set,
-// which is the whole point.
+// WHY ALMOST EVERY EXPECTATION HERE IS A FLOAT VALUE, and why that is not an accident of the
+// demotion: the shader reports through a `float` SSBO, and every value chosen is exact in
+// float32, so the same number is correct in both regimes and the assertions test the LAYOUT
+// rather than the precision. Exactly one case (GetUniformdvReadsBackWhatWasStored) uses a value
+// that is not - 0.1 - and it names both answers explicitly.
 
 #include <cmath>
+#include <cstring>
 #include <string>
 #include <vector>
 
@@ -153,6 +158,151 @@ void main() {
             std::string m_buildLog;
         };
 
+        // A SHADER STORAGE BLOCK that holds doubles is the one place the narrowing is NOT free:
+        // demoting `double` to `float` also repacks the block, and the bytes the application
+        // wrote into the buffer do not move with it. Every member past the first double then
+        // reads and writes at the wrong offset, and the block is simply shorter than the one
+        // that was bound - the tail of it is never touched at all
+        // (KHR-GL43.shader_storage_buffer_object.basic-stdLayout-case3, whose output matched its
+        // input up to the first double's slot and was zero from there on).
+        //
+        // The block layout is fixed by GL 4.6 core 7.6.2.2 and is asserted here as literal byte
+        // offsets rather than queried, so this says what the SPEC requires and not what MobileGL
+        // happens to report. Both packings are covered because they differ in exactly the places
+        // that matter: std140 rounds an array's stride and a matrix's column stride up to 16,
+        // std430 does not, and only std430 packs the scalars tightly.
+        //
+        // Every value is exactly representable in binary32, so a correct implementation copies
+        // the block BYTE FOR BYTE even though it narrows each double on the way through.
+        constexpr const char* kBlockCopySource = R"(#version 430 core
+layout(local_size_x = 1) in;
+layout(std140, binding = 0) buffer In140 {
+    int    data0;
+    float  data1[3];
+    mat3x2 data2;
+    double data3;
+    double data4[2];
+    int    data5;
+    dvec3  data6;
+} g_in140;
+layout(std430, binding = 1) buffer In430 {
+    int    data0;
+    float  data1[3];
+    mat3x2 data2;
+    double data3;
+    double data4[2];
+    int    data5;
+    dvec3  data6;
+} g_in430;
+layout(std140, binding = 2) buffer Out140 {
+    int    data0;
+    float  data1[3];
+    mat3x2 data2;
+    double data3;
+    double data4[2];
+    int    data5;
+    dvec3  data6;
+} g_out140;
+layout(std430, binding = 3) buffer Out430 {
+    int    data0;
+    float  data1[3];
+    mat3x2 data2;
+    double data3;
+    double data4[2];
+    int    data5;
+    dvec3  data6;
+} g_out430;
+void main() {
+    g_out140.data0 = g_in140.data0;
+    for (int i = 0; i < 3; ++i) g_out140.data1[i] = g_in140.data1[i];
+    g_out140.data2 = g_in140.data2;
+    g_out140.data3 = g_in140.data3;
+    for (int i = 0; i < 2; ++i) g_out140.data4[i] = g_in140.data4[i];
+    g_out140.data5 = g_in140.data5;
+    g_out140.data6 = g_in140.data6;
+
+    g_out430.data0 = g_in430.data0;
+    for (int i = 0; i < 3; ++i) g_out430.data1[i] = g_in430.data1[i];
+    g_out430.data2 = g_in430.data2;
+    g_out430.data3 = g_in430.data3;
+    for (int i = 0; i < 2; ++i) g_out430.data4[i] = g_in430.data4[i];
+    g_out430.data5 = g_in430.data5;
+    g_out430.data6 = g_in430.data6;
+}
+)";
+
+        // GL 4.6 core 7.6.2.2 rule by rule, for the block above.
+        //   std140: an array's element stride and a matrix's column stride round up to 16, a
+        //           double aligns to 8 and a dvec3 to 32.
+        //   std430: the same without the rounding - so the scalars pack tightly and only the
+        //           dvec3's 32-byte alignment leaves a hole.
+        struct BlockLayout {
+            int data0;
+            int data1;
+            int data1Stride;
+            int data2;
+            int data2ColumnStride;
+            int data3;
+            int data4;
+            int data4Stride;
+            int data5;
+            int data6;
+            int size;
+        };
+        constexpr BlockLayout kStd140{0, 16, 16, 64, 16, 112, 128, 16, 160, 192, 216};
+        constexpr BlockLayout kStd430{0, 4, 4, 16, 8, 40, 48, 8, 64, 96, 120};
+
+        void PokeInt(std::vector<unsigned char>& bytes, int offset, int value) {
+            std::memcpy(&bytes[static_cast<std::size_t>(offset)], &value, sizeof(value));
+        }
+        void PokeFloat(std::vector<unsigned char>& bytes, int offset, float value) {
+            std::memcpy(&bytes[static_cast<std::size_t>(offset)], &value, sizeof(value));
+        }
+        void PokeDouble(std::vector<unsigned char>& bytes, int offset, double value) {
+            std::memcpy(&bytes[static_cast<std::size_t>(offset)], &value, sizeof(value));
+        }
+
+        // The block's contents, at the offsets the standard puts them. Padding stays zero, which
+        // is what makes a byte-for-byte comparison against the (zero-initialised) output buffer
+        // catch a member that landed somewhere it should not have.
+        std::vector<unsigned char> MakeBlockContents(const BlockLayout& layout) {
+            std::vector<unsigned char> bytes(static_cast<std::size_t>(layout.size), 0);
+            PokeInt(bytes, layout.data0, 1);
+            for (int i = 0; i < 3; ++i) {
+                PokeFloat(bytes, layout.data1 + i * layout.data1Stride, 2.0f + static_cast<float>(i));
+            }
+            // Column-major, two rows per column.
+            for (int column = 0; column < 3; ++column) {
+                for (int row = 0; row < 2; ++row) {
+                    PokeFloat(bytes, layout.data2 + column * layout.data2ColumnStride + row * 4,
+                              5.0f + static_cast<float>(column * 2 + row));
+                }
+            }
+            PokeDouble(bytes, layout.data3, 11.0);
+            for (int i = 0; i < 2; ++i) {
+                PokeDouble(bytes, layout.data4 + i * layout.data4Stride, 12.0 + static_cast<double>(i));
+            }
+            PokeInt(bytes, layout.data5, 14);
+            for (int i = 0; i < 3; ++i) {
+                PokeDouble(bytes, layout.data6 + i * 8, 15.0 + static_cast<double>(i));
+            }
+            return bytes;
+        }
+
+        // Names the first byte that differs, and which member owns it, so a failure is a
+        // diagnosis rather than "the buffer is wrong".
+        std::string DescribeOffset(const BlockLayout& layout, int offset) {
+            const std::pair<int, const char*> members[] = {
+                {layout.data0, "data0"}, {layout.data1, "data1"}, {layout.data2, "data2"},
+                {layout.data3, "data3"}, {layout.data4, "data4"}, {layout.data5, "data5"},
+                {layout.data6, "data6"}};
+            const char* owner = "(padding before data0)";
+            for (const auto& [start, name] : members) {
+                if (offset >= start) owner = name;
+            }
+            return std::string(owner);
+        }
+
         // Every double-typed uniform shape GLSL has, all thirteen of them, in one program - the
         // shape of KHR-GL43.compute_shader.fp64-case2. The scalar and the square matrices are
         // covered by the cases above; what only a set like this reaches is the NON-SQUARE
@@ -428,12 +578,24 @@ void main() {
             glUseProgram(0);
 
             // The readback has to undo exactly what the write did - the same std140 column
-            // padding, the same 4-byte components - or a dmat4 comes back with its columns
-            // shifted and nothing else in the API would say so.
+            // padding, the same component width - or a dmat4 comes back with its columns
+            // shifted and nothing else in the API would say so. Every value below except the
+            // scalar is exact in float32, so those expectations pin the LAYOUT and hold in
+            // either regime; the scalar is the one that also pins the PRECISION.
             GLdouble readScalar = 0.0;
             glGetUniformdv(m_program, scalar, &readScalar);
-            EXPECT_DOUBLE_EQ(readScalar, static_cast<double>(static_cast<float>(0.1)))
-                << "the value is what a float can hold, not the double that was passed in";
+            // 0.1 is not representable in float32, so what comes back names the regime: a
+            // backend without native fp64 narrowed it at the glUniform1d above (the module's own
+            // doubles were demoted, so its storage is 4 bytes per component), and one with it
+            // stored the double whole. Both are correct; asserting only the narrow answer would
+            // fail the moment fp64 stops being emulated, and asserting only the wide one would
+            // fail on every mobile device there is.
+            if (readScalar == 0.1) {
+                SUCCEED() << "this backend consumes 64-bit floats natively; the double survived whole";
+            } else {
+                EXPECT_DOUBLE_EQ(readScalar, static_cast<double>(static_cast<float>(0.1)))
+                    << "the value is what a float can hold, not the double that was passed in";
+            }
 
             GLdouble readVector[3] = {};
             glGetUniformdv(m_program, vector, readVector);
@@ -447,7 +609,8 @@ void main() {
                 EXPECT_DOUBLE_EQ(readMatrix[i], 100.0 + i) << "dmat4 component " << i;
             }
 
-            // The float query sees the same storage through the type it is actually stored as.
+            // The float query sees the same storage through a narrower type, and answers the
+            // same float either way: GL 4.6 core 7.6 converts on the way out.
             GLfloat readFloat = 0.0f;
             glGetUniformfv(m_program, scalar, &readFloat);
             EXPECT_FLOAT_EQ(readFloat, static_cast<float>(0.1));
@@ -697,24 +860,188 @@ void main() {
             EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR));
         }
 
-        TEST_F(DoublePrecisionScenario, A64BitVertexFormatIsDeclinedOnEveryBackend) {
+        TEST_F(DoublePrecisionScenario, A64BitVertexFormatIsRecordedAndItsArrayIsDroppedAtDraw) {
             if (!Ready()) return;
             // The demotion leaves no 64-bit shader input to feed, so there is nothing a 64-bit
             // vertex FETCH could be fetched into - on either backend, and no longer only on the
-            // ones whose device lacks shaderFloat64. Declined loudly rather than accepted and
-            // drawn as garbage; the matching POST row says the same thing at startup.
+            // ones whose device lacks shaderFloat64.
+            //
+            // What that costs is the ARRAY, not the CALL. GL 4.6 core 10.3.2 defines no error for
+            // a well-formed glVertexAttribLFormat and 64-bit attributes are core in the GL 4.3
+            // context MobileGL advertises, so refusing the call would be non-conformant and would
+            // leave four pure state queries unanswerable
+            // (KHR-GL43.vertex_attrib_binding.basic-state1/3). The format is therefore recorded and
+            // queryable; the enabled array is what gets dropped, and the attribute then reads its
+            // generic current value. The matching POST row says exactly that at startup.
             GLuint vao = 0;
             glGenVertexArrays(1, &vao);
             glBindVertexArray(vao);
             while (glGetError() != GL_NO_ERROR) {}
 
-            glVertexAttribLFormat(0, 3, GL_DOUBLE, 0);
-            EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_INVALID_OPERATION));
+            glVertexAttribLFormat(1, 3, GL_DOUBLE, 8);
+            EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR))
+                << "glVertexAttribLFormat is a legal call in a GL 4.3 context";
+
+            GLint attribSize = 0;
+            GLint attribType = 0;
+            GLint attribIsLong = 0;
+            GLint attribRelativeOffset = 0;
+            glGetVertexAttribiv(1, GL_VERTEX_ATTRIB_ARRAY_SIZE, &attribSize);
+            glGetVertexAttribiv(1, GL_VERTEX_ATTRIB_ARRAY_TYPE, &attribType);
+            glGetVertexAttribiv(1, GL_VERTEX_ATTRIB_ARRAY_LONG, &attribIsLong);
+            glGetVertexAttribiv(1, GL_VERTEX_ATTRIB_RELATIVE_OFFSET, &attribRelativeOffset);
+            EXPECT_EQ(attribSize, 3);
+            EXPECT_EQ(attribType, static_cast<GLint>(GL_DOUBLE));
+            EXPECT_EQ(attribIsLong, GL_TRUE) << "GL_VERTEX_ATTRIB_ARRAY_LONG is what makes this the "
+                                                "unconverted form; without it the state is a lie";
+            EXPECT_EQ(attribRelativeOffset, 8);
+            EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR));
 
             glBindVertexArray(0);
             glDeleteVertexArrays(1, &vao);
             while (glGetError() != GL_NO_ERROR) {}
         }
 
+        // The consequence of recording the state rather than refusing the call: a 64-bit array can
+        // now be ENABLED in a VAO that a draw uses, which it never could before. That must not
+        // take the draw down. Leaving such an array enabled with no pointer behind it is exactly
+        // the documented Adreno null-deref (SIGSEGV inside the next glDraw*), so DirectGLES
+        // disables it before glVertexAttribPointer can ever see GL_DOUBLE, and DirectVulkan maps
+        // the format to VK_FORMAT_UNDEFINED so it never enters the pipeline's vertex input state.
+        //
+        // The shader deliberately does NOT read location 1: that keeps the two backends on the
+        // same path (DirectVulkan declines a draw whose SHADER reads an unsupported enabled array,
+        // by design and loudly, which is a different assertion from this one) and it is the shape
+        // the crash needed - an enabled array nothing set a pointer for.
+        TEST_F(DoublePrecisionScenario, AnEnabledLongArrayDoesNotBreakADrawThatIgnoresIt) {
+            if (!Ready()) return;
+
+            constexpr const char* kVs = R"(#version 430 core
+layout(location = 0) in vec2 aPos;
+void main() { gl_Position = vec4(aPos, 0.0, 1.0); }
+)";
+            constexpr const char* kFs = R"(#version 430 core
+out vec4 o_color;
+void main() { o_color = vec4(0.0, 1.0, 0.0, 1.0); }
+)";
+            std::string error;
+            const unsigned int program = CompileProgram(kVs, kFs, &error);
+            ASSERT_NE(program, 0u) << error;
+
+            ColorFbo target = MakeColorFbo(32, 32);
+            ASSERT_NE(target.fbo, 0u) << "could not create the render target";
+            BindFbo(target);
+
+            const float positions[8] = {-1.0f, -1.0f, 1.0f, -1.0f, -1.0f, 1.0f, 1.0f, 1.0f};
+            const double doubles[4] = {1.0, 2.0, 3.0, 4.0};
+
+            GLuint vao = 0;
+            GLuint positionBuffer = 0;
+            GLuint doubleBuffer = 0;
+            glGenVertexArrays(1, &vao);
+            glBindVertexArray(vao);
+            glGenBuffers(1, &positionBuffer);
+            glBindBuffer(GL_ARRAY_BUFFER, positionBuffer);
+            glBufferData(GL_ARRAY_BUFFER, sizeof(positions), positions, GL_STATIC_DRAW);
+            glGenBuffers(1, &doubleBuffer);
+            glBindBuffer(GL_ARRAY_BUFFER, doubleBuffer);
+            glBufferData(GL_ARRAY_BUFFER, sizeof(doubles), doubles, GL_STATIC_DRAW);
+            glBindBuffer(GL_ARRAY_BUFFER, 0);
+
+            glVertexAttribFormat(0, 2, GL_FLOAT, GL_FALSE, 0);
+            glVertexAttribBinding(0, 0);
+            glBindVertexBuffer(0, positionBuffer, 0, static_cast<GLsizei>(2 * sizeof(float)));
+            glEnableVertexAttribArray(0);
+
+            glVertexAttribLFormat(1, 1, GL_DOUBLE, 0);
+            glVertexAttribBinding(1, 1);
+            glBindVertexBuffer(1, doubleBuffer, 0, static_cast<GLsizei>(sizeof(double)));
+            glEnableVertexAttribArray(1);
+            EXPECT_EQ(FirstGLError(), 0u) << "setting up the 64-bit array was refused";
+
+            ClearTo(0.0f, 0.0f, 0.0f, 1.0f);
+            glUseProgram(program);
+            glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+            EXPECT_EQ(FirstGLError(), 0u) << "a draw with an enabled 64-bit array must not raise an error";
+
+            const Image image = ReadPixels(target.width, target.height);
+            ASSERT_FALSE(image.Empty());
+            EXPECT_GT(image.At(target.width / 2, target.height / 2).g, 200)
+                << "the draw did not happen; the enabled 64-bit array must be dropped, not fatal";
+
+            glDisableVertexAttribArray(0);
+            glDisableVertexAttribArray(1);
+            glBindVertexArray(0);
+            glDeleteVertexArrays(1, &vao);
+            glDeleteBuffers(1, &positionBuffer);
+            glDeleteBuffers(1, &doubleBuffer);
+            BindDefaultFramebuffer();
+            DestroyColorFbo(target);
+            glUseProgram(0);
+            glDeleteProgram(program);
+            EXPECT_EQ(FirstGLError(), 0u);
+        }
+
+        TEST_F(DoublePrecisionScenario, AStorageBlockWithDoublesKeepsTheLayoutItWasBoundWith) {
+            if (!Ready()) return;
+
+            GLint blocks = 0;
+            glGetIntegerv(GL_MAX_COMPUTE_SHADER_STORAGE_BLOCKS, &blocks);
+            if (blocks < 4) {
+                GTEST_SKIP() << "GL_MAX_COMPUTE_SHADER_STORAGE_BLOCKS is " << blocks << "; this needs 4";
+            }
+
+            const unsigned int program = CompileComputeProgram(kBlockCopySource);
+            ASSERT_NE(program, 0u) << m_buildLog;
+
+            const std::vector<unsigned char> in140 = MakeBlockContents(kStd140);
+            const std::vector<unsigned char> in430 = MakeBlockContents(kStd430);
+            const std::vector<unsigned char> zero140(in140.size(), 0);
+            const std::vector<unsigned char> zero430(in430.size(), 0);
+
+            GLuint buffers[4] = {};
+            glGenBuffers(4, buffers);
+            const std::vector<unsigned char>* contents[4] = {&in140, &in430, &zero140, &zero430};
+            for (int i = 0; i < 4; ++i) {
+                glBindBufferBase(GL_SHADER_STORAGE_BUFFER, static_cast<GLuint>(i), buffers[i]);
+                glBufferData(GL_SHADER_STORAGE_BUFFER, static_cast<GLsizeiptr>(contents[i]->size()),
+                             contents[i]->data(), GL_DYNAMIC_COPY);
+            }
+            ASSERT_EQ(FirstGLError(), 0u);
+
+            glUseProgram(program);
+            glDispatchCompute(1, 1, 1);
+            glMemoryBarrier(GL_BUFFER_UPDATE_BARRIER_BIT);
+            EXPECT_EQ(FirstGLError(), 0u);
+
+            for (int pass = 0; pass < 2; ++pass) {
+                const BlockLayout& layout = pass == 0 ? kStd140 : kStd430;
+                const std::vector<unsigned char>& expected = pass == 0 ? in140 : in430;
+                const char* packing = pass == 0 ? "std140" : "std430";
+                std::vector<unsigned char> observed(expected.size(), 0xEE);
+                glBindBuffer(GL_SHADER_STORAGE_BUFFER, buffers[2 + pass]);
+                glGetBufferSubData(GL_SHADER_STORAGE_BUFFER, 0,
+                                   static_cast<GLsizeiptr>(observed.size()), observed.data());
+                int mismatches = 0;
+                int firstMismatch = -1;
+                for (std::size_t i = 0; i < expected.size(); ++i) {
+                    if (expected[i] == observed[i]) continue;
+                    ++mismatches;
+                    if (firstMismatch < 0) firstMismatch = static_cast<int>(i);
+                }
+                EXPECT_EQ(mismatches, 0)
+                    << packing << " block: " << mismatches << " of " << expected.size()
+                    << " bytes differ, first at byte " << firstMismatch << " (in "
+                    << DescribeOffset(layout, firstMismatch < 0 ? 0 : firstMismatch)
+                    << "); a block that was repacked around its doubles reads and writes every "
+                       "member after the first one at the wrong offset";
+            }
+
+            glUseProgram(0);
+            glDeleteProgram(program);
+            glDeleteBuffers(4, buffers);
+            EXPECT_EQ(FirstGLError(), 0u);
+        }
+
     } // namespace
 } // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/FormatlessImageBakeScenario.cpp

@@ -0,0 +1,211 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/FormatlessImageBakeScenario.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - A FORMAT-LESS IMAGE UNIFORM WHOSE UNIT HOLDS A NON-CORE FORMAT.
+//
+// GLSL 4.20 lets a write-only image uniform omit its layout format; GLSL ES demands one, so
+// DirectGLES BAKES the format of whatever glBindImageTexture put on the unit into the
+// declaration. When that format is outside the GLSL ES core thirteen, the bake alone is not
+// enough - the baked declaration then has to go through the same channel-widening
+// WidenImageFormatsForEssl gives a DECLARED non-core format (see NonCoreImageFormatScenario for
+// the widening itself).
+//
+// The two routes had different arming. The declared route armed the widening on the format
+// alone; the baked route armed it only when the driver lacked GL_NV_image_formats. That reads
+// like an optimisation and is not one: SPIRV-Cross throws for its is_desktop_only_format set the
+// moment it targets ESSL, whatever the driver would have accepted, so on a driver that HAS the
+// extension the shader half of the widening stayed switched off while TextureImpl's storage/bind
+// half - which keys on SpirvCrossCanPrintEsslImageFormat, not on the driver bit - still ran. The
+// stage threw, the program linked without it, and every dispatch silently did nothing.
+//
+// KHR-GL43.stencil_texturing.functional is where it surfaced: its compute half writes through a
+// format-less `uimage2D` bound to an R8UI texture, and returned zeros for every texel.
+//
+// DISCRIMINATING ONLY WHERE THE DRIVER ADVERTISES GL_NV_image_formats - Mesa does, which is what
+// the software lanes run and where this was found. On Adreno 830 and both Malis the extension is
+// absent, the old code already armed the widening, and these cases pass before and after; they
+// are kept running there as a guard against the opposite mistake.
+
+#include <cstdint>
+#include <cstring>
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        constexpr int kExtent = 8;
+
+        // No layout format on uni_image on purpose: that is the whole subject. uni_source is a
+        // plain integer texture so nothing but the image declaration is in play.
+        const char* const kComputeSource = R"(#version 430 core
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+writeonly uniform uimage2D uni_image;
+uniform usampler2D uni_source;
+void main()
+{
+    ivec2 at = ivec2(gl_GlobalInvocationID.xy);
+    imageStore(uni_image, at, uvec4(texelFetch(uni_source, at, 0).r, 0u, 0u, 0u));
+}
+)";
+
+        class FormatlessImageBakeScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                if (!BackendHostsCompute()) {
+                    GTEST_SKIP() << "no compute stage on " << Gl().BackendName() << " ("
+                                 << Gl().RendererString() << ")";
+                }
+            }
+
+            static bool BackendHostsCompute() {
+                GLint maxImageUnits = 0;
+                glGetIntegerv(GL_MAX_IMAGE_UNITS, &maxImageUnits);
+                DrainErrors();
+                return maxImageUnits >= 2;
+            }
+
+            static void DrainErrors() {
+                for (int i = 0; i < 16 && glGetError() != GL_NO_ERROR; ++i) {
+                }
+            }
+
+            static GLuint BuildCompute(const char* source, std::string& log) {
+                const GLuint cs = glCreateShader(GL_COMPUTE_SHADER);
+                glShaderSource(cs, 1, &source, nullptr);
+                glCompileShader(cs);
+                GLint ok = 0;
+                glGetShaderiv(cs, GL_COMPILE_STATUS, &ok);
+                if (!ok) {
+                    char buffer[2048] = "";
+                    glGetShaderInfoLog(cs, sizeof(buffer), nullptr, buffer);
+                    log = buffer;
+                    glDeleteShader(cs);
+                    return 0;
+                }
+                const GLuint program = glCreateProgram();
+                glAttachShader(program, cs);
+                glLinkProgram(program);
+                glGetProgramiv(program, GL_LINK_STATUS, &ok);
+                glDeleteShader(cs);
+                if (!ok) {
+                    char buffer[2048] = "";
+                    glGetProgramInfoLog(program, sizeof(buffer), nullptr, buffer);
+                    log = buffer;
+                    glDeleteProgram(program);
+                    return 0;
+                }
+                return program;
+            }
+
+            // internalFormat is the NON-CORE image format under test; the destination texture and
+            // the glBindImageTexture argument both use it, and the shader declares nothing.
+            void RunCopy(GLenum internalFormat, GLenum uploadFormat, GLenum uploadType) {
+                std::vector<GLuint> expected(kExtent * kExtent);
+                for (int i = 0; i < kExtent * kExtent; ++i) {
+                    expected[i] = static_cast<GLuint>(1 + i);
+                }
+
+                // Source: a core-format integer texture holding 1..64.
+                std::vector<GLubyte> sourceBytes(kExtent * kExtent);
+                for (int i = 0; i < kExtent * kExtent; ++i) {
+                    sourceBytes[i] = static_cast<GLubyte>(expected[i]);
+                }
+                GLuint sourceTexture = 0;
+                glGenTextures(1, &sourceTexture);
+                glBindTexture(GL_TEXTURE_2D, sourceTexture);
+                glTexStorage2D(GL_TEXTURE_2D, 1, GL_R8UI, kExtent, kExtent);
+                glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, kExtent, kExtent, GL_RED_INTEGER, GL_UNSIGNED_BYTE,
+                                sourceBytes.data());
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+
+                // Destination: the format under test, zero-filled so "the dispatch did nothing"
+                // and "the dispatch wrote zeros" are the same observation the CTS made.
+                GLuint destTexture = 0;
+                glGenTextures(1, &destTexture);
+                glBindTexture(GL_TEXTURE_2D, destTexture);
+                glTexStorage2D(GL_TEXTURE_2D, 1, internalFormat, kExtent, kExtent);
+                const std::vector<GLubyte> zeros(static_cast<std::size_t>(kExtent) * kExtent * 8, 0);
+                glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, kExtent, kExtent, uploadFormat, uploadType, zeros.data());
+                ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "destination storage";
+
+                std::string log;
+                const GLuint program = BuildCompute(kComputeSource, log);
+                ASSERT_NE(program, 0u) << "the format-less image program did not build: " << log;
+
+                glUseProgram(program);
+                glBindImageTexture(1, destTexture, 0, GL_FALSE, 0, GL_WRITE_ONLY, internalFormat);
+                glUniform1i(glGetUniformLocation(program, "uni_image"), 1);
+                glActiveTexture(GL_TEXTURE1);
+                glBindTexture(GL_TEXTURE_2D, sourceTexture);
+                glUniform1i(glGetUniformLocation(program, "uni_source"), 1);
+                ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "binding";
+
+                glDispatchCompute(kExtent, kExtent, 1);
+                glMemoryBarrier(GL_ALL_BARRIER_BITS);
+                EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "dispatch";
+
+                std::vector<GLuint> readback(kExtent * kExtent, 0xFFFFFFFFu);
+                glActiveTexture(GL_TEXTURE0);
+                glBindTexture(GL_TEXTURE_2D, destTexture);
+                glGetTexImage(GL_TEXTURE_2D, 0, GL_RED_INTEGER, GL_UNSIGNED_INT, readback.data());
+                EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "readback";
+
+                int offenders = 0;
+                for (int i = 0; i < kExtent * kExtent; ++i) {
+                    if (readback[i] != expected[i]) ++offenders;
+                }
+                EXPECT_EQ(offenders, 0) << "the dispatch wrote " << offenders << " of "
+                                        << (kExtent * kExtent) << " texels wrongly; texel 0 was "
+                                        << readback[0] << ", expected " << expected[0]
+                                        << ". A whole stage lost to the ESSL emitter looks exactly like this.";
+
+                glUseProgram(0);
+                glDeleteProgram(program);
+                glDeleteTextures(1, &sourceTexture);
+                glDeleteTextures(1, &destTexture);
+                DrainErrors();
+            }
+        };
+
+        // R8UI: one of the seven formats GLSL ES reaches only through GL_NV_image_formats AND one
+        // SPIRV-Cross refuses to print for ESSL, so it needs the widening in both driver modes.
+        TEST_F(FormatlessImageBakeScenario, R8uiBakedFromTheBoundUnitStillReachesTheDriver) {
+            if (!Ready()) GTEST_SKIP();
+            RunCopy(GL_R8UI, GL_RED_INTEGER, GL_UNSIGNED_BYTE);
+        }
+
+        // R16UI, from the same set, carried in RGBA16UI: the fix must not be R8UI-shaped.
+        TEST_F(FormatlessImageBakeScenario, R16uiBakedFromTheBoundUnitStillReachesTheDriver) {
+            if (!Ready()) GTEST_SKIP();
+            RunCopy(GL_R16UI, GL_RED_INTEGER, GL_UNSIGNED_SHORT);
+        }
+
+        // The control: R32UI is in the GLSL ES core thirteen, so it is baked and never widened.
+        // It passed before the fix and has to keep passing.
+        TEST_F(FormatlessImageBakeScenario, CoreFormatBakedFromTheBoundUnitIsUnaffected) {
+            if (!Ready()) GTEST_SKIP();
+            RunCopy(GL_R32UI, GL_RED_INTEGER, GL_UNSIGNED_INT);
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/GeometryDrawModeScenario.cpp

@@ -0,0 +1,413 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/GeometryDrawModeScenario.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - A GEOMETRY SHADER'S INPUT PRIMITIVE CONSTRAINS THE DRAW MODE, AND
+// GL_NONE IS NOT A USABLE "NO GEOMETRY SHADER" SENTINEL.
+//
+// GL 4.6 core 11.3.1: mode must be one of the primitive types that decomposes into the
+// geometry shader's declared input primitive, or the draw is GL_INVALID_OPERATION. The
+// validator asked "is there a geometry stage?" by comparing the REFLECTED INPUT PRIMITIVE
+// against GL_NONE - and GL_NONE and GL_POINTS are both 0, so a `layout(points) in` geometry
+// shader answered "no geometry stage" and every mode sailed through. The rule was therefore
+// dead for exactly the geometry shaders whose input primitive rejects the most modes.
+//
+// KHR-GL43.transform_feedback.api_errors_test is where it showed: it draws a points-in
+// geometry program with GL_LINES through glDrawTransformFeedbackInstanced and requires
+// INVALID_OPERATION. The bug is not specific to that entry point - every draw shares this
+// validator - so the ordinary glDrawArrays spelling is pinned here too, and the lines-in
+// program is the control that proves the rule was not simply widened.
+//
+// Needs a real context: the validator returns before this rule when no backend object is
+// active, so the GPU-free negative-API suite cannot reach it.
+
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        const char* const kVertexSource = R"(#version 420 core
+void main()
+{
+    gl_Position = vec4(0.0, 0.0, 0.0, 1.0);
+}
+)";
+
+        // The input primitive the CTS case uses, and the one the GL_NONE sentinel erased.
+        // `result` is here so the same program can be captured with transform feedback.
+        const char* const kPointsInGeometrySource = R"(#version 420 core
+layout(points) in;
+layout(points, max_vertices = 1) out;
+out float result;
+void main()
+{
+    gl_Position = gl_in[0].gl_Position;
+    result = 1.0;
+    EmitVertex();
+}
+)";
+
+        const char* const kLinesInGeometrySource = R"(#version 420 core
+layout(lines) in;
+layout(points, max_vertices = 1) out;
+void main()
+{
+    gl_Position = gl_in[0].gl_Position;
+    EmitVertex();
+}
+)";
+
+        const char* const kFragmentSource = R"(#version 420 core
+out vec4 fragColor;
+void main()
+{
+    fragColor = vec4(0.0, 1.0, 0.0, 1.0);
+}
+)";
+
+        class GeometryDrawModeScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                glGenVertexArrays(1, &m_vao);
+                glBindVertexArray(m_vao);
+                if (!BackendHostsGeometry()) {
+                    GTEST_SKIP() << "no geometry stage on " << Gl().BackendName() << " ("
+                                 << Gl().RendererString() << "); there is no input primitive to validate";
+                }
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                glUseProgram(0);
+                for (const GLuint program : m_programs) {
+                    glDeleteProgram(program);
+                }
+                m_programs.clear();
+                glBindVertexArray(0);
+                if (m_vao != 0) glDeleteVertexArrays(1, &m_vao);
+                m_vao = 0;
+            }
+
+            // The same real-backend probe IoBlockNameCollisionScenario uses: 0 on a DirectGLES
+            // driver without GL_EXT_geometry_shader and on a DirectVulkan device without the
+            // geometryShader feature.
+            static bool BackendHostsGeometry() {
+                GLint maxGeometryOutputVertices = 0;
+                glGetIntegerv(GL_MAX_GEOMETRY_OUTPUT_VERTICES, &maxGeometryOutputVertices);
+                DrainErrors();
+                return maxGeometryOutputVertices >= 4;
+            }
+
+            static void DrainErrors() {
+                for (int i = 0; i < 16 && glGetError() != GL_NO_ERROR; ++i) {
+                }
+            }
+
+            GLuint BuildProgram(const char* geometrySource, const char* capturedVarying = nullptr) {
+                const std::vector<std::pair<GLenum, const char*>> stages = {
+                    {GL_VERTEX_SHADER, kVertexSource},
+                    {GL_GEOMETRY_SHADER, geometrySource},
+                    {GL_FRAGMENT_SHADER, kFragmentSource}};
+
+                std::vector<GLuint> shaders;
+                bool ok = true;
+                for (const auto& [stage, source] : stages) {
+                    const GLuint shader = glCreateShader(stage);
+                    glShaderSource(shader, 1, &source, nullptr);
+                    glCompileShader(shader);
+                    GLint compiled = 0;
+                    glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
+                    shaders.push_back(shader);
+                    if (!compiled) {
+                        m_buildLog = InfoLog(shader, true);
+                        ok = false;
+                        break;
+                    }
+                }
+                if (!ok) {
+                    for (const GLuint shader : shaders) glDeleteShader(shader);
+                    return 0;
+                }
+
+                const GLuint program = glCreateProgram();
+                for (const GLuint shader : shaders) glAttachShader(program, shader);
+                if (capturedVarying != nullptr) {
+                    glTransformFeedbackVaryings(program, 1, &capturedVarying, GL_INTERLEAVED_ATTRIBS);
+                }
+                glLinkProgram(program);
+                GLint linked = 0;
+                glGetProgramiv(program, GL_LINK_STATUS, &linked);
+                for (const GLuint shader : shaders) glDeleteShader(shader);
+                if (!linked) {
+                    m_buildLog = InfoLog(program, false);
+                    glDeleteProgram(program);
+                    return 0;
+                }
+                m_programs.push_back(program);
+                return program;
+            }
+
+            static std::string InfoLog(GLuint object, bool isShader) {
+                GLint length = 0;
+                if (isShader) {
+                    glGetShaderiv(object, GL_INFO_LOG_LENGTH, &length);
+                } else {
+                    glGetProgramiv(object, GL_INFO_LOG_LENGTH, &length);
+                }
+                std::vector<char> buffer(static_cast<std::size_t>(length) + 1, '\0');
+                if (isShader) {
+                    glGetShaderInfoLog(object, length + 1, nullptr, buffer.data());
+                } else {
+                    glGetProgramInfoLog(object, length + 1, nullptr, buffer.data());
+                }
+                return buffer.data();
+            }
+
+            const std::string& BuildLog() const { return m_buildLog; }
+
+            GLuint m_vao = 0;
+            std::vector<GLuint> m_programs;
+            std::string m_buildLog;
+        };
+
+        // GL_POINTS is the only mode that decomposes into a points input primitive.
+        TEST_F(GeometryDrawModeScenario, PointsInGeometryProgramRejectsEveryOtherMode) {
+            if (!Ready()) GTEST_SKIP();
+
+            const GLuint program = BuildProgram(kPointsInGeometrySource);
+            ASSERT_NE(program, 0u) << "the points-in geometry program did not build: " << BuildLog();
+
+            glUseProgram(program);
+            DrainErrors();
+
+            for (const GLenum mode :
+                 {static_cast<GLenum>(GL_LINES), static_cast<GLenum>(GL_LINE_STRIP),
+                  static_cast<GLenum>(GL_TRIANGLES), static_cast<GLenum>(GL_TRIANGLE_STRIP)}) {
+                glDrawArrays(mode, 0, 3);
+                EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_INVALID_OPERATION))
+                    << "mode " << mode << " does not decompose into the geometry shader's points input";
+                DrainErrors();
+            }
+
+            // The one mode that IS compatible still draws.
+            glDrawArrays(GL_POINTS, 0, 1);
+            EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR));
+            DrainErrors();
+        }
+
+        // The same rule reached through glDrawTransformFeedback*, which is the spelling the CTS
+        // case asks about. The capture span is really completed first, so GL_POINTS comes back
+        // GL_NO_ERROR: without that the draw would report INVALID_OPERATION for the
+        // never-ended-a-span reason instead and the case could not tell the two apart.
+        TEST_F(GeometryDrawModeScenario, PointsInGeometryProgramRejectsNonPointModesOnFeedbackDraws) {
+            if (!Ready()) GTEST_SKIP();
+
+            const GLuint program = BuildProgram(kPointsInGeometrySource, "result");
+            ASSERT_NE(program, 0u) << "the points-in geometry program did not build: " << BuildLog();
+
+            GLuint feedback = 0;
+            glGenTransformFeedbacks(1, &feedback);
+            glBindTransformFeedback(GL_TRANSFORM_FEEDBACK, feedback);
+            GLuint captureBuffer = 0;
+            glGenBuffers(1, &captureBuffer);
+            glBindBuffer(GL_TRANSFORM_FEEDBACK_BUFFER, captureBuffer);
+            glBufferData(GL_TRANSFORM_FEEDBACK_BUFFER, 64, nullptr, GL_STATIC_DRAW);
+            glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, captureBuffer);
+            glUseProgram(program);
+            DrainErrors();
+
+            glBeginTransformFeedback(GL_POINTS);
+            glDrawArrays(GL_POINTS, 0, 1);
+            glEndTransformFeedback();
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR)) << "the capture span did not complete";
+
+            glDrawTransformFeedbackInstanced(GL_LINES, feedback, 1);
+            EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_INVALID_OPERATION))
+                << "glDrawTransformFeedbackInstanced must honour the geometry input primitive";
+            DrainErrors();
+
+            glDrawTransformFeedbackStreamInstanced(GL_LINES, feedback, 0, 1);
+            EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_INVALID_OPERATION))
+                << "glDrawTransformFeedbackStreamInstanced must honour the geometry input primitive";
+            DrainErrors();
+
+            // The compatible mode replays the captured span with no error at all, which is what
+            // makes the two assertions above about the MODE and not about the span.
+            glDrawTransformFeedbackInstanced(GL_POINTS, feedback, 1);
+            EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR))
+                << "a compatible mode must still replay the captured span";
+            DrainErrors();
+
+            glUseProgram(0);
+            glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, 0);
+            glBindBuffer(GL_TRANSFORM_FEEDBACK_BUFFER, 0);
+            glDeleteBuffers(1, &captureBuffer);
+            glBindTransformFeedback(GL_TRANSFORM_FEEDBACK, 0);
+            glDeleteTransformFeedbacks(1, &feedback);
+            DrainErrors();
+        }
+
+        // The control: a lines-in geometry shader is a NON-zero input primitive, so it exercised
+        // the rule even before the fix. It must still accept the line modes and still reject the
+        // others - a fix that widened the rule instead of repairing its guard breaks this.
+        TEST_F(GeometryDrawModeScenario, LinesInGeometryProgramStillAcceptsLineModesOnly) {
+            if (!Ready()) GTEST_SKIP();
+
+            const GLuint program = BuildProgram(kLinesInGeometrySource);
+            ASSERT_NE(program, 0u) << "the lines-in geometry program did not build: " << BuildLog();
+
+            glUseProgram(program);
+            DrainErrors();
+
+            for (const GLenum mode : {static_cast<GLenum>(GL_LINES), static_cast<GLenum>(GL_LINE_STRIP),
+                                      static_cast<GLenum>(GL_LINE_LOOP)}) {
+                glDrawArrays(mode, 0, 2);
+                EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR))
+                    << "mode " << mode << " decomposes into lines and must be accepted";
+                DrainErrors();
+            }
+
+            for (const GLenum mode : {static_cast<GLenum>(GL_POINTS), static_cast<GLenum>(GL_TRIANGLES)}) {
+                glDrawArrays(mode, 0, 3);
+                EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_INVALID_OPERATION))
+                    << "mode " << mode << " does not decompose into lines";
+                DrainErrors();
+            }
+        }
+
+        // The other half of "ask the stage": WHICH stage list is asked. gsInputPrimitive is a
+        // LINK artifact, so pairing it with the live attach list re-points the GL_NONE/GL_POINTS
+        // aliasing instead of removing it - inside the window between glAttachShader and the
+        // next link, the live list says "geometry present" while the artifact still reads
+        // GL_NONE, which is 0, which is GL_POINTS, so every mode but GL_POINTS is rejected.
+        //
+        // GL 4.6 core 7.3 makes that window legal and ordinary: an attach affects the program's
+        // executable only at the next link, and leaves LINK_STATUS alone. The attached shader
+        // need not even compile. Worse, it does not heal - glDetachShader defers the removal to
+        // the next Link() too, so the program would keep failing every non-POINTS draw until the
+        // application happened to relink for some unrelated reason.
+        TEST_F(GeometryDrawModeScenario, AttachingAGeometryStageAfterTheLinkDoesNotConstrainTheDrawMode) {
+            if (!Ready()) GTEST_SKIP();
+
+            // Deliberately NOT BuildProgram: the executable under test has no geometry stage.
+            const GLuint program = glCreateProgram();
+            m_programs.push_back(program);
+            for (const auto& [stage, source] :
+                 std::vector<std::pair<GLenum, const char*>>{{GL_VERTEX_SHADER, kVertexSource},
+                                                             {GL_FRAGMENT_SHADER, kFragmentSource}}) {
+                const GLuint shader = glCreateShader(stage);
+                glShaderSource(shader, 1, &source, nullptr);
+                glCompileShader(shader);
+                glAttachShader(program, shader);
+                glDeleteShader(shader);
+            }
+            glLinkProgram(program);
+            GLint linked = GL_FALSE;
+            glGetProgramiv(program, GL_LINK_STATUS, &linked);
+            ASSERT_EQ(linked, GL_TRUE) << "the vertex+fragment program did not link";
+
+            glUseProgram(program);
+            DrainErrors();
+            glDrawArrays(GL_TRIANGLES, 0, 3);
+            ASSERT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR))
+                << "a program with no geometry stage must draw triangles";
+            DrainErrors();
+
+            const GLuint geometry = glCreateShader(GL_GEOMETRY_SHADER);
+            glShaderSource(geometry, 1, &kPointsInGeometrySource, nullptr);
+            glCompileShader(geometry);
+            glAttachShader(program, geometry);
+            glDeleteShader(geometry);
+            DrainErrors();
+
+            // Same executable as three lines ago - no relink has happened.
+            glDrawArrays(GL_TRIANGLES, 0, 3);
+            EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR))
+                << "the attach does not reach the executable until the next link, so the geometry "
+                   "shader's points input must not constrain this draw";
+            DrainErrors();
+
+            // And once it IS linked in, the rule applies - the fix must not have simply disabled it.
+            glLinkProgram(program);
+            glGetProgramiv(program, GL_LINK_STATUS, &linked);
+            ASSERT_EQ(linked, GL_TRUE) << "the relink with the geometry stage failed";
+            glUseProgram(program);
+            DrainErrors();
+            glDrawArrays(GL_TRIANGLES, 0, 3);
+            EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_INVALID_OPERATION))
+                << "now that the points-in geometry shader is in the executable, triangles must be rejected";
+            DrainErrors();
+        }
+
+        // The tessellation guard above the geometry one had the identical defect, and it does not
+        // even need the GL_NONE aliasing to misfire: it drives BOTH directions unconditionally, so
+        // reading the live attach list rejects every non-GL_PATCHES draw the moment an evaluation
+        // shader is attached, whether or not it was ever linked in.
+        TEST_F(GeometryDrawModeScenario, AttachingATessEvalStageAfterTheLinkDoesNotForceGlPatches) {
+            if (!Ready()) GTEST_SKIP();
+
+            GLint maxPatchVertices = 0;
+            glGetIntegerv(GL_MAX_PATCH_VERTICES, &maxPatchVertices);
+            DrainErrors();
+            if (maxPatchVertices < 3) GTEST_SKIP() << "no tessellation stage on this backend";
+
+            const GLuint program = glCreateProgram();
+            m_programs.push_back(program);
+            for (const auto& [stage, source] :
+                 std::vector<std::pair<GLenum, const char*>>{{GL_VERTEX_SHADER, kVertexSource},
+                                                             {GL_FRAGMENT_SHADER, kFragmentSource}}) {
+                const GLuint shader = glCreateShader(stage);
+                glShaderSource(shader, 1, &source, nullptr);
+                glCompileShader(shader);
+                glAttachShader(program, shader);
+                glDeleteShader(shader);
+            }
+            glLinkProgram(program);
+            GLint linked = GL_FALSE;
+            glGetProgramiv(program, GL_LINK_STATUS, &linked);
+            ASSERT_EQ(linked, GL_TRUE) << "the vertex+fragment program did not link";
+
+            glUseProgram(program);
+            DrainErrors();
+
+            static const char* const kTessEvalSource = R"(#version 420 core
+layout(triangles, equal_spacing, ccw) in;
+void main()
+{
+    gl_Position = gl_in[0].gl_Position;
+}
+)";
+            const GLuint tessEval = glCreateShader(GL_TESS_EVALUATION_SHADER);
+            glShaderSource(tessEval, 1, &kTessEvalSource, nullptr);
+            glCompileShader(tessEval);
+            glAttachShader(program, tessEval);
+            glDeleteShader(tessEval);
+            DrainErrors();
+
+            glDrawArrays(GL_TRIANGLES, 0, 3);
+            EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR))
+                << "the executable still has no tessellation stage, so GL_PATCHES must not be required";
+            DrainErrors();
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/Glsl420DeclarationScenario.cpp

@@ -179,6 +179,13 @@ void main()
 in flat uint v_index;
 out vec4 o_color;
 void main() { o_color = vec4(0.0, 1.0, 0.0, 1.0); }
+)";
+
+        // The colour index spelled out at its default value. Says nothing that
+        // `layout(location = 0)` alone does not, and must therefore cost nothing.
+        constexpr const char* kExplicitColorIndexFS = R"(#version 420 core
+layout(location = 0, index = 0) out vec4 o_color;
+void main() { o_color = vec4(0.0, 1.0, 0.0, 1.0); }
 )";
 
         class Glsl420DeclarationScenario : public ScenarioTest {
@@ -473,4 +480,24 @@ void main() { o_color = vec4(0.0, 1.0, 0.0, 1.0); }
         EXPECT_EQ(centre.g, 255) << "the atomic-counter shader linked but painted nothing";
     }
 
+    // `layout(location = 0, index = 0)` is the GL default written out loud, and an application
+    // is entitled to write it - KHR-GL43.shader_atomic_counters.basic-program-query does. It has
+    // to reach the driver as an ORDINARY single-source output: GLSL ES has no `index` qualifier
+    // in core, so a transpiler that prints the decoration back gets "index layout qualifier
+    // requires EXT_blend_func_extended", the stage never compiles, the program runs with a stage
+    // missing and the draw paints nothing at all. Black, not red - which is why the conformance
+    // case looked like the atomic counters had stopped counting.
+    TEST_F(Glsl420DeclarationScenario, AnExplicitDefaultColorIndexStillDraws) {
+        if (!Ready()) return;
+
+        const GLuint program = Build(kQuadVS, kExplicitColorIndexFS);
+        if (program == 0) return;
+
+        const Rgba8 centre = DrawAndRead(program);
+        EXPECT_EQ(FirstGLError(), 0u);
+        EXPECT_EQ(centre.g, 255) << "a fragment output declared layout(location = 0, index = 0) painted "
+                                    "nothing; its stage was almost certainly refused by the driver";
+        EXPECT_EQ(centre.r, 0u);
+    }
+
 } // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/ImageFormatQualifierScenario.cpp

@@ -0,0 +1,314 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/ImageFormatQualifierScenario.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - AN IMAGE UNIFORM THAT DECLARES NO FORMAT.
+//
+// Desktop GLSL 4.2 lets a writeonly image declaration omit its format layout qualifier:
+//
+//     writeonly uniform uimage2D uni_image;      // legal desktop GLSL
+//
+// GLSL ES has no such relaxation; every image uniform must carry one, and Adreno says so as "all
+// images have to define layout format", which fails the whole program. That is what took the
+// compute half of KHR-GL4x.packed_depth_stencil.stencil_texturing.
+//
+// The only qualifier that is CORRECT to substitute is whatever glBindImageTexture named for the
+// unit that uniform addresses - GL requires the qualifier, the bind format and the texture's
+// internal format to belong to one format class - so the format is not knowable when the shader
+// is compiled, only when it is drawn with. Espryt therefore BAKES it into the program it
+// generates and keys that program on the (unit, format) pairs it baked
+// (BackendProgramObjectImpl::ImageUnitFormatsStillMatch, MG_Backend/DirectGLES).
+//
+// Three separate things follow from "the program is built against live binding state", and each
+// one is a case below:
+//
+//   1. the format reaches the shader at all, so the store lands where the texture is (Writes);
+//   2. binding a DIFFERENT format to the same unit rebuilds the program, rather than reusing one
+//      compiled against the old format (RebindToADifferentFormatRebuilds);
+//   3. an image bound for the FIRST time after the link works, i.e. the program built against
+//      "nothing bound yet" is not the one the dispatch runs (FirstBindAfterLinkRebuilds).
+//
+// Magma needs none of this - Vulkan takes an Unknown-format storage image given
+// shaderStorageImageWriteWithoutFormat, and the view format is resolved from the same bind state
+// at descriptor time - so every case here runs on both backends and must agree, which is what
+// makes the ES-only machinery falsifiable rather than merely exercised.
+
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        constexpr int kExtent = 4;
+        // The image unit is deliberately NOT 0 and the uniform declares no binding, so the unit
+        // has to travel through glUniform1i and be baked into the ESSL alongside the format -
+        // the two bakes share a rebuild key and a bug in either shows up as the wrong texel.
+        constexpr GLint kImageUnit = 1;
+
+        // KHR-GL4x.packed_depth_stencil.stencil_texturing's own image declaration, verbatim.
+        const char* kStoreSource = R"(#version 430 core
+
+layout (local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+
+writeonly uniform uimage2D uni_image;
+
+void main()
+{
+    imageStore(uni_image, ivec2(gl_GlobalInvocationID.xy), uvec4(gl_GlobalInvocationID.x + 100u, 0u, 0u, 0u));
+}
+)";
+
+        class ImageFormatQualifierScenario : public ScenarioTest {
+        protected:
+            void TearDown() override {
+                if (!Ready()) return;
+                glUseProgram(0);
+                for (GLuint p : m_programs) glDeleteProgram(p);
+                for (GLuint t : m_textures) glDeleteTextures(1, &t);
+                m_programs.clear();
+                m_textures.clear();
+                GLint maxImageUnits = 0;
+                glGetIntegerv(GL_MAX_IMAGE_UNITS, &maxImageUnits);
+                for (GLint unit = 0; unit < maxImageUnits; ++unit) {
+                    glBindImageTexture(static_cast<GLuint>(unit), 0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_R32UI);
+                }
+                while (glGetError() != GL_NO_ERROR) {
+                }
+            }
+
+            bool ImagesAreUsable() const {
+                GLint maxImageUnits = 0;
+                glGetIntegerv(GL_MAX_IMAGE_UNITS, &maxImageUnits);
+                GLint maxComputeImageUniforms = 0;
+                glGetIntegerv(GL_MAX_COMPUTE_IMAGE_UNIFORMS, &maxComputeImageUniforms);
+                while (glGetError() != GL_NO_ERROR) {
+                }
+                return maxImageUnits > kImageUnit && maxComputeImageUniforms >= 1;
+            }
+
+            GLuint MakeComputeProgram(const std::string& source) {
+                const GLuint shader = glCreateShader(GL_COMPUTE_SHADER);
+                const char* text = source.c_str();
+                glShaderSource(shader, 1, &text, nullptr);
+                glCompileShader(shader);
+                GLint compiled = GL_FALSE;
+                glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
+                if (compiled == GL_FALSE) {
+                    char log[4096] = {};
+                    glGetShaderInfoLog(shader, sizeof(log) - 1, nullptr, log);
+                    ADD_FAILURE() << "the compute shader did not compile: " << log;
+                    glDeleteShader(shader);
+                    return 0;
+                }
+                const GLuint program = glCreateProgram();
+                m_programs.push_back(program);
+                glAttachShader(program, shader);
+                glLinkProgram(program);
+                glDeleteShader(shader);
+                GLint linked = GL_FALSE;
+                glGetProgramiv(program, GL_LINK_STATUS, &linked);
+                if (linked == GL_FALSE) {
+                    char log[4096] = {};
+                    glGetProgramInfoLog(program, sizeof(log) - 1, nullptr, log);
+                    ADD_FAILURE() << "the compute program did not link: " << log;
+                    return 0;
+                }
+                return program;
+            }
+
+            GLuint MakeTexture(GLenum internalFormat) {
+                GLuint texture = 0;
+                glGenTextures(1, &texture);
+                m_textures.push_back(texture);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                glTexStorage2D(GL_TEXTURE_2D, 1, internalFormat, kExtent, kExtent);
+                if (const GLenum error = FirstGLError()) {
+                    ADD_FAILURE() << "allocating storage errored with " << GLErrorName(error);
+                    return 0;
+                }
+                // Seeded to a value no dispatch writes, so "the store never happened" and "the
+                // store wrote the right thing" cannot be confused.
+                const std::vector<GLuint> zeros(static_cast<std::size_t>(kExtent) * kExtent * 4u, 0u);
+                glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, kExtent, kExtent,
+                                internalFormat == GL_RGBA32UI ? GL_RGBA_INTEGER : GL_RED_INTEGER, GL_UNSIGNED_INT,
+                                zeros.data());
+                while (glGetError() != GL_NO_ERROR) {
+                }
+                return texture;
+            }
+
+            // Texel (x, 0) of the texture's red channel, read back through the GL frontend rather
+            // than through a second image uniform: a defect in the format bake would be shared by
+            // a reader declared the same way and could cancel itself out.
+            GLuint ReadRedTexel(GLuint texture, GLenum internalFormat, int x) {
+                const bool rgba = internalFormat == GL_RGBA32UI;
+                std::vector<GLuint> texels(static_cast<std::size_t>(kExtent) * kExtent * (rgba ? 4u : 1u),
+                                           0xFFFFFFFFu);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                glGetTexImage(GL_TEXTURE_2D, 0, rgba ? GL_RGBA_INTEGER : GL_RED_INTEGER, GL_UNSIGNED_INT,
+                              texels.data());
+                if (const GLenum error = FirstGLError()) {
+                    ADD_FAILURE() << "reading the image back errored with " << GLErrorName(error);
+                    return 0xFFFFFFFFu;
+                }
+                return texels[static_cast<std::size_t>(x) * (rgba ? 4u : 1u)];
+            }
+
+            void DispatchStore(GLuint program, GLuint texture, GLenum internalFormat) {
+                glBindImageTexture(static_cast<GLuint>(kImageUnit), texture, 0, GL_FALSE, 0, GL_WRITE_ONLY,
+                                   internalFormat);
+                ASSERT_EQ(FirstGLError(), 0u) << "glBindImageTexture errored";
+                glUseProgram(program);
+                const GLint location = glGetUniformLocation(program, "uni_image");
+                ASSERT_GE(location, 0) << "the image uniform was not reflected";
+                glUniform1i(location, kImageUnit);
+                ASSERT_EQ(FirstGLError(), 0u) << "assigning the image unit errored";
+                glDispatchCompute(kExtent, 1, 1);
+                glMemoryBarrier(GL_ALL_BARRIER_BITS);
+                EXPECT_EQ(FirstGLError(), 0u) << "the dispatch leaked a GL error";
+                glUseProgram(0);
+            }
+
+            std::vector<GLuint> m_programs;
+            std::vector<GLuint> m_textures;
+        };
+
+        // The defect itself. Without the bake the ES driver refuses the program outright and the
+        // texture keeps its seed - which is also exactly what a silently no-op dispatch looks
+        // like, and why the seed is a value no store writes.
+        TEST_F(ImageFormatQualifierScenario, AFormatlessWriteonlyImageWrites) {
+            if (!Ready()) GTEST_SKIP() << "no GL context";
+            if (!ImagesAreUsable()) GTEST_SKIP() << "no image load/store on this driver";
+
+            const GLuint program = MakeComputeProgram(kStoreSource);
+            const GLuint texture = MakeTexture(GL_R32UI);
+            if (program == 0 || texture == 0) return;
+
+            DispatchStore(program, texture, GL_R32UI);
+            for (int x = 0; x < kExtent; ++x) {
+                EXPECT_EQ(ReadRedTexel(texture, GL_R32UI, x), static_cast<GLuint>(x) + 100u)
+                    << "texel " << x << " of a format-less writeonly image did not take the store";
+            }
+        }
+
+        // The rebuild key. The SAME program is dispatched twice with a different format bound to
+        // its unit; a build keyed only on the link (or only on the image UNIT) would reuse the
+        // r32ui program for the rgba32ui texture, and the second half would come back seeded.
+        //
+        // What the SOFTWARE lanes cannot falsify: with the key disabled this case still passes on
+        // Mesa, because the reused r32ui declaration writes the red channel of an RGBA32UI image
+        // anyway - a format-class mismatch GL leaves undefined and that driver happens to absorb.
+        // FirstBindAfterLinkRebuilds below is the case that fails there, because the reused
+        // program was built with no format at all and never compiled. Both are kept: this one is
+        // the shape a strict driver is entitled to reject, and it is the shape the device runs.
+        TEST_F(ImageFormatQualifierScenario, RebindToADifferentFormatRebuilds) {
+            if (!Ready()) GTEST_SKIP() << "no GL context";
+            if (!ImagesAreUsable()) GTEST_SKIP() << "no image load/store on this driver";
+
+            const GLuint program = MakeComputeProgram(kStoreSource);
+            const GLuint first = MakeTexture(GL_R32UI);
+            const GLuint second = MakeTexture(GL_RGBA32UI);
+            if (program == 0 || first == 0 || second == 0) return;
+
+            DispatchStore(program, first, GL_R32UI);
+            for (int x = 0; x < kExtent; ++x) {
+                ASSERT_EQ(ReadRedTexel(first, GL_R32UI, x), static_cast<GLuint>(x) + 100u)
+                    << "the first format must work before the rebind can be blamed for anything";
+            }
+
+            DispatchStore(program, second, GL_RGBA32UI);
+            for (int x = 0; x < kExtent; ++x) {
+                EXPECT_EQ(ReadRedTexel(second, GL_RGBA32UI, x), static_cast<GLuint>(x) + 100u)
+                    << "texel " << x << ": the program was not rebuilt for the newly bound format";
+            }
+
+            // ...and back, so the rebuild is not a one-way door: returning to a format the
+            // program was once built against must build for it again, not resurrect a cache row.
+            const GLuint third = MakeTexture(GL_R32UI);
+            if (third == 0) return;
+            DispatchStore(program, third, GL_R32UI);
+            for (int x = 0; x < kExtent; ++x) {
+                EXPECT_EQ(ReadRedTexel(third, GL_R32UI, x), static_cast<GLuint>(x) + 100u)
+                    << "texel " << x << ": going back to the first format did not rebuild";
+            }
+        }
+
+        // Nothing is bound to the unit when the program links, so whatever the first build sees
+        // is not the format the dispatch needs. glBindImageTexture must not itself trigger a
+        // build - it is an entry point, and building there is the constraint
+        // glShaderStorageBlockBinding is held to as well - so the rebuild has to happen at the
+        // next dispatch preparation instead. This case fails either way round: no rebuild, or a
+        // build attempted from the entry point before the state settles.
+        TEST_F(ImageFormatQualifierScenario, FirstBindAfterLinkRebuilds) {
+            if (!Ready()) GTEST_SKIP() << "no GL context";
+            if (!ImagesAreUsable()) GTEST_SKIP() << "no image load/store on this driver";
+
+            const GLuint program = MakeComputeProgram(kStoreSource);
+            if (program == 0) return;
+
+            // Use it once with NOTHING bound to the unit, which is what makes the backend build
+            // against an empty binding. The dispatch writes nowhere and must not error.
+            glUseProgram(program);
+            const GLint location = glGetUniformLocation(program, "uni_image");
+            ASSERT_GE(location, 0);
+            glUniform1i(location, kImageUnit);
+            glDispatchCompute(kExtent, 1, 1);
+            glMemoryBarrier(GL_ALL_BARRIER_BITS);
+            EXPECT_EQ(FirstGLError(), 0u) << "dispatching with an unbound image unit must not error";
+            glUseProgram(0);
+
+            const GLuint texture = MakeTexture(GL_R32UI);
+            if (texture == 0) return;
+            DispatchStore(program, texture, GL_R32UI);
+            for (int x = 0; x < kExtent; ++x) {
+                EXPECT_EQ(ReadRedTexel(texture, GL_R32UI, x), static_cast<GLuint>(x) + 100u)
+                    << "texel " << x << ": the first bind after the link did not reach the shader";
+            }
+        }
+
+        // A DECLARED format is authoritative and the bake must never touch it - including when
+        // the texture behind the unit has a different (but class-compatible) internal format,
+        // which GL explicitly allows. If the bake ever overrode a declaration, this is the case
+        // that would go wrong while every other one stayed green.
+        TEST_F(ImageFormatQualifierScenario, ADeclaredFormatStillWins) {
+            if (!Ready()) GTEST_SKIP() << "no GL context";
+            if (!ImagesAreUsable()) GTEST_SKIP() << "no image load/store on this driver";
+
+            const GLuint program = MakeComputeProgram(R"(#version 430 core
+
+layout (local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+
+layout (r32ui) writeonly uniform uimage2D uni_image;
+
+void main()
+{
+    imageStore(uni_image, ivec2(gl_GlobalInvocationID.xy), uvec4(gl_GlobalInvocationID.x + 100u, 0u, 0u, 0u));
+}
+)");
+            const GLuint texture = MakeTexture(GL_R32UI);
+            if (program == 0 || texture == 0) return;
+
+            DispatchStore(program, texture, GL_R32UI);
+            for (int x = 0; x < kExtent; ++x) {
+                EXPECT_EQ(ReadRedTexel(texture, GL_R32UI, x), static_cast<GLuint>(x) + 100u)
+                    << "texel " << x << ": a declared format stopped working";
+            }
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/ImageLoadStoreSsoScenario.cpp

@@ -127,14 +127,23 @@ void main()
             // One qualifier is all an ARRAY declaration can carry, and ESSL then gives the
             // array's elements the CONSECUTIVE units N, N+1, N+2, ... - so a per-element
             // assignment that is not consecutive (the conformance case uses 0, 2, 4, 6) has no
-            // spelling in a single declaration and cannot be expressed at all without splitting
-            // the array into one declaration per element and rewriting every use of it.
+            // spelling in a single declaration.
             //
-            // Scoped rather than disabled, exactly as ProgramPipelineScenario scopes its
-            // storage-block rebinding cases: the defect is per-backend and the frontend
-            // mechanism these cases exist for - per-element units surviving the trip to the
-            // pipeline composite - is fully exercised on Magma.
-            bool PerElementImageUnitsAreHonoured() const { return Gl().BackendName() == "DirectVulkan"; }
+            // RemapImageArrayElementUnits repairs it by SPLITTING the array into one scalar
+            // image uniform per element, each carrying its own binding, which costs exactly the
+            // four image uniforms the application declared. (It used to WIDEN the array to cover
+            // the whole span instead, which cost seven for those four elements and had to be
+            // declined on a stage that could not afford them - hence the budget gate that used
+            // to be here.) DirectVulkan needs no rewrite at all.
+            bool PerElementImageUnitsAreHonoured() const {
+                if (Gl().BackendName() == "DirectVulkan") return true;
+                GLint maxFragmentImageUniforms = 0;
+                glGetIntegerv(GL_MAX_FRAGMENT_IMAGE_UNIFORMS, &maxFragmentImageUniforms);
+                while (glGetError() != GL_NO_ERROR) {
+                }
+                // One per element of the four-element array either fragment program declares.
+                return maxFragmentImageUniforms >= 4;
+            }
 
             // The scenarios below need image load/store at all; a driver without it should skip
             // rather than fail.
@@ -164,7 +173,7 @@ void main()
         if (!Ready()) return;
         if (!ImagesAreUsable()) GTEST_SKIP() << "fewer than 8 image units";
         if (!PerElementImageUnitsAreHonoured()) {
-            GTEST_SKIP() << "non-consecutive per-element image units cannot be baked into ESSL";
+            GTEST_SKIP() << "fewer than 4 fragment image uniforms: the array under test does not fit";
         }
         HeadlessGL& gl = Gl();
 
@@ -283,8 +292,12 @@ void main()
     TEST_F(ImageLoadStoreSsoScenario, AnImageArrayAlongsideAnotherDescriptorKeepsBothBindings) {
         if (!Ready()) return;
         if (!ImagesAreUsable()) GTEST_SKIP() << "fewer than 8 image units";
-        if (!PerElementImageUnitsAreHonoured()) {
-            GTEST_SKIP() << "non-consecutive per-element image units cannot be baked into ESSL";
+        // The defect this guards is the SPIR-V descriptor remap, which only Magma has; the units
+        // here are consecutive on purpose, so on Espryt this would exercise nothing the case
+        // above does not. Scoped by what it TESTS rather than by the image-array widening, which
+        // it deliberately never triggers.
+        if (Gl().BackendName() != "DirectVulkan") {
+            GTEST_SKIP() << "the descriptor binding remap under test is DirectVulkan's";
         }
         HeadlessGL& gl = Gl();
 

MobileGL/MG_IntegrationTest/Scenarios/ImageSizeAfterRespecScenario.cpp

@@ -0,0 +1,234 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/ImageSizeAfterRespecScenario.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - A DRAW READS imageSize() AFTER THE IMAGE TEXTURE IS RE-SPECIFIED.
+//
+// KHR-GL43.shader_image_size.advanced-changeSize reduced to its mechanism. The application binds
+// a texture to an image unit ONCE, draws, then re-specifies that same texture with a new size
+// through glTexImage2D and draws again - without touching the image unit. GL says the unit
+// references the texture OBJECT, so the second draw must see the new dimensions.
+//
+// On Espryt it did not, and the reason is two facts meeting:
+//
+//   1. ES 3.1 only allows IMMUTABLE storage on an image unit, so the backend forces glTexStorage
+//      backing on any texture that reaches one (SyncTextureObjectToBackend's
+//      imageBindableStorageRequired). Immutable storage cannot be redefined, so a glTexImage2D
+//      that changes size or format has to MINT A NEW ES TEXTURE NAME.
+//   2. The draw path never re-issued glBindImageTexture. Image units were established eagerly,
+//      once, when the application called glBindImageTexture, and PrepareForDraw only ever
+//      re-synced SAMPLED textures - so the unit kept pointing at the deleted name and
+//      imageSize() reported whatever that stale binding still meant.
+//
+// A dispatch was never affected: PrepareForCompute has always swept the image units. This is a
+// draw-path scenario for exactly that reason - a compute-shaped case cannot see the defect.
+//
+// Both backends run it. Magma re-derives its image descriptors per draw and so was never wrong
+// here, which makes it the control: the two backends have to agree on what the second draw sees.
+
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        constexpr int kTargetSize = 8;
+
+        constexpr const char* kVS = R"(#version 430 core
+void main()
+{
+    // A single triangle that covers the whole target, with no vertex buffer at all: the
+    // scenario is about the image unit, so nothing else may be able to make it fail.
+    switch (gl_VertexID)
+    {
+      case 0: gl_Position = vec4(-1.0, -1.0, 0.0, 1.0); break;
+      case 1: gl_Position = vec4( 3.0, -1.0, 0.0, 1.0); break;
+      case 2: gl_Position = vec4(-1.0,  3.0, 0.0, 1.0); break;
+    }
+}
+)";
+
+        // Green when the image the unit currently holds has the size the application last gave
+        // it, red otherwise - the conformance case's own comparison, and its own colours.
+        constexpr const char* kFS = R"(#version 430 core
+layout(rgba8) readonly uniform image2D g_image;
+uniform ivec2 g_expected_size;
+layout(location = 0) out vec4 o_color;
+void main()
+{
+    o_color = (imageSize(g_image) == g_expected_size) ? vec4(0.0, 1.0, 0.0, 1.0) : vec4(1.0, 0.0, 0.0, 1.0);
+}
+)";
+
+        class ImageSizeAfterRespecScenario : public ScenarioTest {
+        protected:
+            void TearDown() override {
+                if (!Ready()) return;
+                glUseProgram(0);
+                glBindImageTexture(0, 0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+                glBindFramebuffer(GL_FRAMEBUFFER, 0);
+                if (m_program != 0) glDeleteProgram(m_program);
+                if (m_fbo != 0) glDeleteFramebuffers(1, &m_fbo);
+                if (m_color != 0) glDeleteTextures(1, &m_color);
+                if (m_image != 0) glDeleteTextures(1, &m_image);
+                if (m_vao != 0) glDeleteVertexArrays(1, &m_vao);
+                m_program = m_fbo = m_color = m_image = m_vao = 0;
+                while (glGetError() != GL_NO_ERROR) {
+                }
+            }
+
+            // imageSize() needs a fragment-stage image uniform; a driver that serves none should
+            // skip rather than fail.
+            bool FragmentImagesAreUsable() const {
+                GLint maxImageUnits = 0;
+                GLint maxFragmentImageUniforms = 0;
+                glGetIntegerv(GL_MAX_IMAGE_UNITS, &maxImageUnits);
+                glGetIntegerv(GL_MAX_FRAGMENT_IMAGE_UNIFORMS, &maxFragmentImageUniforms);
+                while (glGetError() != GL_NO_ERROR) {
+                }
+                return maxImageUnits >= 1 && maxFragmentImageUniforms >= 1;
+            }
+
+            GLuint MakeProgram() {
+                const GLuint vs = glCreateShader(GL_VERTEX_SHADER);
+                const GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
+                glShaderSource(vs, 1, &kVS, nullptr);
+                glShaderSource(fs, 1, &kFS, nullptr);
+                glCompileShader(vs);
+                glCompileShader(fs);
+                for (const GLuint shader : {vs, fs}) {
+                    GLint compiled = GL_FALSE;
+                    glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
+                    if (compiled == GL_FALSE) {
+                        char log[4096] = {};
+                        glGetShaderInfoLog(shader, sizeof(log) - 1, nullptr, log);
+                        ADD_FAILURE() << "a shader did not compile: " << log;
+                        glDeleteShader(vs);
+                        glDeleteShader(fs);
+                        return 0;
+                    }
+                }
+                const GLuint program = glCreateProgram();
+                glAttachShader(program, vs);
+                glAttachShader(program, fs);
+                glLinkProgram(program);
+                glDeleteShader(vs);
+                glDeleteShader(fs);
+                GLint linked = GL_FALSE;
+                glGetProgramiv(program, GL_LINK_STATUS, &linked);
+                if (linked == GL_FALSE) {
+                    char log[4096] = {};
+                    glGetProgramInfoLog(program, sizeof(log) - 1, nullptr, log);
+                    ADD_FAILURE() << "the program did not link: " << log;
+                    glDeleteProgram(program);
+                    return 0;
+                }
+                return program;
+            }
+
+            void MakeRenderTarget() {
+                glGenTextures(1, &m_color);
+                glBindTexture(GL_TEXTURE_2D, m_color);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, kTargetSize, kTargetSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
+                             nullptr);
+                glGenFramebuffers(1, &m_fbo);
+                glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
+                glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_color, 0);
+            }
+
+            // Draw once with `expected` pushed to the shader and report the centre pixel.
+            void DrawAndReadCentre(int expectedWidth, int expectedHeight, unsigned char (&centre)[4]) {
+                const GLint location = glGetUniformLocation(m_program, "g_expected_size");
+                ASSERT_NE(location, -1) << "the program has no g_expected_size uniform";
+                glUseProgram(m_program);
+                glUniform2i(location, expectedWidth, expectedHeight);
+                glViewport(0, 0, kTargetSize, kTargetSize);
+                glDisable(GL_SCISSOR_TEST);
+                glDisable(GL_DEPTH_TEST);
+                glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
+                glClear(GL_COLOR_BUFFER_BIT);
+                glDrawArrays(GL_TRIANGLES, 0, 3);
+                ASSERT_EQ(FirstGLError(), 0u) << "the draw left a GL error";
+
+                std::vector<unsigned char> pixels(static_cast<std::size_t>(kTargetSize) * kTargetSize * 4, 0);
+                glReadPixels(0, 0, kTargetSize, kTargetSize, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());
+                ASSERT_EQ(FirstGLError(), 0u) << "reading the target back errored";
+                const std::size_t offset =
+                    (static_cast<std::size_t>(kTargetSize / 2) * kTargetSize + kTargetSize / 2) * 4;
+                for (int i = 0; i < 4; ++i) {
+                    centre[i] = pixels[offset + static_cast<std::size_t>(i)];
+                }
+            }
+
+            GLuint m_program = 0;
+            GLuint m_fbo = 0;
+            GLuint m_color = 0;
+            GLuint m_image = 0;
+            GLuint m_vao = 0;
+        };
+
+    } // namespace
+
+    // The whole conformance shape: bind once, draw, re-specify the SAME texture smaller, draw
+    // again. The first draw is the control - it proves the binding and the shader work at all -
+    // and the second is the regression pin. Blue would mean the draw never ran; red means the
+    // image unit answered with the size the texture had BEFORE the re-spec.
+    TEST_F(ImageSizeAfterRespecScenario, ADrawSeesTheNewSizeOfARespecifiedImageTexture) {
+        if (!Ready()) return;
+        if (!FragmentImagesAreUsable()) GTEST_SKIP() << "no fragment-stage image uniform available";
+
+        m_program = MakeProgram();
+        if (m_program == 0) return;
+        glGenVertexArrays(1, &m_vao);
+        glBindVertexArray(m_vao);
+        MakeRenderTarget();
+        ASSERT_EQ(FirstGLError(), 0u) << "setting the render target up errored";
+
+        glGenTextures(1, &m_image);
+        glBindTexture(GL_TEXTURE_2D, m_image);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 32, 32, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+        glBindImageTexture(0, m_image, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+        ASSERT_EQ(FirstGLError(), 0u) << "binding the image texture errored";
+
+        unsigned char centre[4] = {0, 0, 0, 0};
+        DrawAndReadCentre(32, 32, centre);
+        EXPECT_EQ(static_cast<int>(centre[0]), 0) << "the FIRST draw already disagrees about imageSize(): got ("
+                                                  << static_cast<int>(centre[0]) << ", "
+                                                  << static_cast<int>(centre[1]) << ", "
+                                                  << static_cast<int>(centre[2]) << ")";
+        EXPECT_EQ(static_cast<int>(centre[1]), 255);
+
+        // The re-spec. The image unit is deliberately NOT re-bound: GL 4.6 core 8.26 says the
+        // unit references the texture object, so this alone has to be visible to the next draw.
+        glBindTexture(GL_TEXTURE_2D, m_image);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 16, 16, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+        ASSERT_EQ(FirstGLError(), 0u) << "re-specifying the image texture errored";
+
+        DrawAndReadCentre(16, 16, centre);
+        EXPECT_EQ(static_cast<int>(centre[0]), 0)
+            << "after the re-spec the draw still sees the OLD image size; centre pixel was ("
+            << static_cast<int>(centre[0]) << ", " << static_cast<int>(centre[1]) << ", "
+            << static_cast<int>(centre[2]) << ")";
+        EXPECT_EQ(static_cast<int>(centre[1]), 255);
+    }
+
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/ImageTargetKindScenario.cpp

@@ -66,6 +66,9 @@ namespace MGITest {
         constexpr int kExtent = 6;
         constexpr GLuint kFilledValue = 7u;
         constexpr GLuint kStoredValue = 13u;
+        // What the atomic cases add to a filled texel. Distinct from both values above, so a
+        // wrong answer cannot be read as either the untouched fill or a plain store.
+        constexpr GLuint kAtomicAddend = 5u;
 
         // Everything that differs between the eleven kinds, in one row.
         struct TargetKind {
@@ -129,6 +132,25 @@ namespace MGITest {
                    kind.imageType + " i0;\n\nvoid main()\n{\n    " + StoreStatement(kind, "i0", "13u") + "\n}\n";
         }
 
+        // The third direction, and the one neither of the two above can stand in for: an
+        // imageAtomic* reaches its texel through a SPIR-V operand path of its own
+        // (OpImageTexelPointer), not through OpImageRead or OpImageWrite. SPIRV-Cross's "ES has
+        // no 1D image, address it as 2D" coordinate widening is applied on the read and write
+        // paths and NOT on that one, so a 1D image whose loads and stores are both correct could
+        // still lose its entire stage to a single imageAtomicAdd - which is what
+        // KHR-GL4x.shader_image_load_store.basic-allTargets-atomic measured, with the driver
+        // answering "'imageAtomicAdd' : no matching overloaded function found".
+        //
+        // No readonly/writeonly here: an atomic needs both directions, and r32ui is one of the
+        // three formats GLSL ES exempts from the qualifier rule, so the bare declaration is legal.
+        // Returns the value the texel held BEFORE the add, so one dispatch checks the atomic's
+        // return value and the load case that follows checks its memory effect.
+        std::string SingleAtomicSource(const TargetKind& kind) {
+            return std::string(kComputePrologue) + "layout (location = 0, r32ui) coherent uniform " +
+                   kind.imageType + " i0;\n" + kResultBlock + "void main()\n{\n    ssb.sum = imageAtomicAdd(i0, " +
+                   kind.coord + (kind.multisample ? ", 0, " : ", ") + std::to_string(kAtomicAddend) + "u);\n}\n";
+        }
+
         class ImageTargetKindScenario : public ScenarioTest {
         protected:
             void TearDown() override {
@@ -374,6 +396,119 @@ namespace MGITest {
                 glUseProgram(0);
             }
 
+            // Fill a texture of `kind`, add to texel (0,0,0) atomically, and require BOTH the
+            // value the atomic returned and the value it left behind. The read-back runs as a
+            // second program, for the same reason the store case does: a backend that gets the
+            // atomic's return right and its memory effect wrong cannot cancel itself out.
+            void RunAtomicCase(const TargetKind& kind) {
+                const GLuint atomicProgram = MakeComputeProgram(SingleAtomicSource(kind));
+                const GLuint loadProgram = MakeComputeProgram(SingleLoadSource(kind));
+                if (atomicProgram == 0 || loadProgram == 0) return;
+                const GLuint texture = MakeTexture(kind, true);
+                if (texture == 0) return;
+                const GLuint ssbo = MakeResultBuffer();
+
+                glBindImageTexture(0, texture, 0, GL_TRUE, 0, GL_READ_WRITE, GL_R32UI);
+                ASSERT_EQ(FirstGLError(), 0u) << kind.name << ": glBindImageTexture errored";
+
+                glUseProgram(atomicProgram);
+                glUniform1i(0, 0);
+                glDispatchCompute(1, 1, 1);
+                glMemoryBarrier(GL_ALL_BARRIER_BITS);
+                EXPECT_EQ(FirstGLError(), 0u) << kind.name << ": the atomic dispatch leaked a GL error";
+                EXPECT_EQ(ReadResult(ssbo), kFilledValue)
+                    << kind.name << ": imageAtomicAdd did not return the value the texel held before it";
+
+                glUseProgram(loadProgram);
+                glUniform1i(0, 0);
+                glDispatchCompute(1, 1, 1);
+                glMemoryBarrier(GL_ALL_BARRIER_BITS);
+                EXPECT_EQ(FirstGLError(), 0u) << kind.name << ": the loading dispatch leaked a GL error";
+                EXPECT_EQ(ReadResult(ssbo), kFilledValue + kAtomicAddend)
+                    << kind.name << ": imageAtomicAdd did not leave the sum in the texel";
+                glUseProgram(0);
+            }
+
+            // The same texture, bound four times over, varying nothing but `layered` and `layer`.
+            //
+            // GL 4.6 core 8.26 (and ES 3.2 8.22, word for word): "If the texture identified by
+            // texture does not have multiple layers or faces, the entire texture level is bound,
+            // regardless of the values of layered and layer." REGARDLESS means ignored - not
+            // clamped, and not an error - so every one of the four rows has to read the same texel
+            // out of a target that has no layers, including the two rows that name layer 1 on a
+            // texture whose only layer is 0. DirectGLES used to normalize `layered` and forward
+            // `layer` verbatim; Adreno honours the bogus layer by leaving the image unit reading
+            // zero, which is exactly the two rows KHR-GL42.bind_image_texture.single_layer failed.
+            //
+            // The bindings are checked back as well, because the fix depends on WHERE the
+            // normalization happens: the frontend shadow must keep echoing the application's own
+            // values (gl4cShaderImageLoadStoreTests' CheckBinding compares them exactly), and only
+            // the backend's driver call may drop the layer.
+            void RunNonLayerableLayerSweepCase(const TargetKind& kind) {
+                const GLuint program = MakeComputeProgram(SingleLoadSource(kind));
+                if (program == 0) return;
+                const GLuint texture = MakeTexture(kind, true);
+                if (texture == 0) return;
+
+                // A multisample texture has no TexSubImage, so MakeTexture leaves it unwritten and
+                // it is seeded the way the store cases do it - through a dispatch of its own.
+                const GLuint expected = kind.multisample ? kStoredValue : kFilledValue;
+                if (kind.multisample) {
+                    const GLuint storeProgram = MakeComputeProgram(SingleStoreSource(kind));
+                    if (storeProgram == 0) return;
+                    glBindImageTexture(0, texture, 0, GL_TRUE, 0, GL_READ_WRITE, GL_R32UI);
+                    glUseProgram(storeProgram);
+                    glUniform1i(0, 0);
+                    glDispatchCompute(1, 1, 1);
+                    glMemoryBarrier(GL_ALL_BARRIER_BITS);
+                    ASSERT_EQ(FirstGLError(), 0u) << kind.name << ": seeding the multisample texture errored";
+                }
+
+                const GLuint ssbo = MakeResultBuffer();
+                glUseProgram(program);
+                glUniform1i(0, 0);
+                ASSERT_EQ(FirstGLError(), 0u) << kind.name << ": assigning the image unit errored";
+
+                // glcBindImageTextureTests' own four rows, in its own order.
+                struct LayerRow {
+                    GLboolean layered;
+                    GLint layer;
+                };
+                static constexpr LayerRow kRows[] = {{GL_TRUE, 1}, {GL_TRUE, 0}, {GL_FALSE, 1}, {GL_FALSE, 0}};
+
+                for (const LayerRow& row : kRows) {
+                    const std::string where = std::string(kind.name) +
+                                              ": layered=" + (row.layered == GL_TRUE ? "TRUE" : "FALSE") +
+                                              " layer=" + std::to_string(row.layer);
+                    // Re-zeroed per row, so a row whose binding reads nothing cannot pass on the
+                    // previous row's answer.
+                    const GLuint zero = 0u;
+                    glBindBuffer(GL_SHADER_STORAGE_BUFFER, ssbo);
+                    glBufferSubData(GL_SHADER_STORAGE_BUFFER, 0, sizeof(GLuint), &zero);
+
+                    glBindImageTexture(0, texture, 0, row.layered, row.layer, GL_READ_ONLY, GL_R32UI);
+                    EXPECT_EQ(FirstGLError(), 0u) << where << ": glBindImageTexture errored";
+
+                    GLint reportedLayered = -1;
+                    GLint reportedLayer = -1;
+                    glGetIntegeri_v(GL_IMAGE_BINDING_LAYERED, 0, &reportedLayered);
+                    glGetIntegeri_v(GL_IMAGE_BINDING_LAYER, 0, &reportedLayer);
+                    EXPECT_EQ(reportedLayered, row.layered == GL_TRUE ? 1 : 0)
+                        << where << ": GL_IMAGE_BINDING_LAYERED stopped reporting the application's value";
+                    EXPECT_EQ(reportedLayer, row.layer)
+                        << where << ": GL_IMAGE_BINDING_LAYER stopped reporting the application's value";
+
+                    glDispatchCompute(1, 1, 1);
+                    glMemoryBarrier(GL_ALL_BARRIER_BITS);
+                    EXPECT_EQ(FirstGLError(), 0u) << where << ": the dispatch leaked a GL error";
+                    EXPECT_EQ(ReadResult(ssbo), expected)
+                        << where
+                        << ": the texel did not come back, so the binding named a layer the texture "
+                           "does not have instead of the whole level";
+                }
+                glUseProgram(0);
+            }
+
             std::vector<GLuint> m_programs;
             std::vector<GLuint> m_textures;
             std::vector<GLuint> m_buffers;
@@ -435,6 +570,54 @@ namespace MGITest {
 #undef MGL_DEFINE_LOAD_CASE
 #undef MGL_DEFINE_STORE_CASE
 
+    // ---- and the atomic direction, on the two kinds ES has to emulate -------
+    //
+    // Deliberately NOT every kind. imageAtomic* takes its own SPIR-V operand path
+    // (OpImageTexelPointer), and the only kinds whose coordinate that path has to RESHAPE are the
+    // two 1D ones - everything else addresses its ES texture with the coordinate the application
+    // wrote. GL_TEXTURE_1D_ARRAY is the control (its reshape has been in
+    // Lower1DArrayImagesForEssl from the start, and basic-allTargets-atomic passes on it);
+    // GL_TEXTURE_1D is the one that had none, so `imageAtomicAdd(g_image_1d, coord.x, 2)` reached
+    // the driver as a scalar against an iimage2D and took the whole fragment stage - and its six
+    // other images - with it.
+
+#define MGL_DEFINE_ATOMIC_CASE(CaseName, Kind)                                                                  \
+    TEST_F(ImageTargetKindScenario, AtomicallyAddsTo##CaseName) {                                               \
+        if (!Ready()) return;                                                                                   \
+        if (!ImagesAreUsable()) GTEST_SKIP() << "no compute image uniforms";                                    \
+        RunAtomicCase(Kind);                                                                                    \
+    }
+
+    MGL_DEFINE_ATOMIC_CASE(Texture1D, kKind1D)
+    MGL_DEFINE_ATOMIC_CASE(Texture1DArray, kKind1DArray)
+
+#undef MGL_DEFINE_ATOMIC_CASE
+
+    // ---- and the same texture bound four times, varying only layered/layer ---
+    //
+    // KHR-GL42.bind_image_texture.single_layer's sweep, on the kinds whose backend target has
+    // neither layers nor faces. Two of its four rows name layer 1 on a single-layer texture,
+    // which the spec says is to be ignored outright rather than honoured or rejected - and
+    // which DirectGLES used to forward to the ES driver as written.
+
+#define MGL_DEFINE_LAYER_SWEEP_CASE(CaseName, Kind)                                                             \
+    TEST_F(ImageTargetKindScenario, IgnoresLayerFor##CaseName) {                                                \
+        if (!Ready()) return;                                                                                   \
+        if (!ImagesAreUsable()) GTEST_SKIP() << "no compute image uniforms";                                    \
+        if ((Kind).multisample && !MultisampleImagesAreUsable()) {                                              \
+            GTEST_SKIP() << "GL_MAX_IMAGE_SAMPLES is 0, so the conformance case substitutes a plain 2D image "  \
+                            "here and never asks for a multisample one";                                        \
+        }                                                                                                       \
+        RunNonLayerableLayerSweepCase(Kind);                                                                    \
+    }
+
+    MGL_DEFINE_LAYER_SWEEP_CASE(Texture2D, kKind2D)
+    MGL_DEFINE_LAYER_SWEEP_CASE(Texture1D, kKind1D)
+    MGL_DEFINE_LAYER_SWEEP_CASE(TextureRectangle, kKindRect)
+    MGL_DEFINE_LAYER_SWEEP_CASE(Texture2DMultisample, kKind2DMS)
+
+#undef MGL_DEFINE_LAYER_SWEEP_CASE
+
     // ---- and all of them at once -------------------------------------------
     //
     // The conformance case's actual shape. The single-kind cases above cannot see a defect that

MobileGL/MG_IntegrationTest/Scenarios/IoBlockNameCollisionScenario.cpp

@@ -0,0 +1,389 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/IoBlockNameCollisionScenario.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - ONE BLOCK NAME USED IN BOTH DIRECTIONS BY ONE STAGE STILL CARRIES ITS PAYLOAD.
+//
+// Desktop GLSL keeps SEPARATE name namespaces for input and output interface blocks, so a
+// single stage may legally write
+//
+//     in  TcsData { ... } tes_in[];
+//     out TcsData { ... } tes_out;
+//
+// The tessellation evaluation stage of both interface-block tests in
+// KHR-GL42/43.shading_language_420pack does exactly that, and MobileGL's backend used to
+// hand the shape straight through: SPIRV-Cross splits the namespace the same way glslang
+// does (block_input_names vs block_output_names) and re-emits BOTH blocks under the name
+// TcsData, so the generated ESSL declares two different blocks of one name in one shader.
+// Adreno's ES compiler keeps them apart. Mali's does not - the stage compiles, the program
+// links, and the evaluation stage's writes never reach the geometry stage, which is all 22
+// of that group's Mali failures and none of Adreno's or DirectVulkan's.
+//
+// Both cases below drive the SAME five-stage pipeline (vertex -> tessellation control ->
+// tessellation evaluation -> geometry -> fragment) and differ only in whether the
+// evaluation stage reuses one name. The distinct-name case is the negative control: it is
+// what says a red pixel in the colliding case is about the name and not about this machine's
+// tessellation, its geometry stage, or the block mechanism in general.
+//
+// Colour code, so a failure names its own cause:
+//   green  - the payload crossed all four stage boundaries, which is the pass.
+//   blue   - the clear colour: nothing was drawn at all (the program did not link, or the
+//            backend program was rejected and every draw became a no-op).
+//   red    - the pipeline ran but the plain (non-block) varying did not arrive, i.e. the
+//            failure is not about interface blocks.
+//   black  - the pipeline ran, the plain varying arrived, and the BLOCK payload came back
+//            zeroed or garbage. That is the defect this scenario exists for.
+//
+// llvmpipe and lavapipe run this faithfully but do NOT reproduce the original defect - the
+// aliasing is a Mali ES compiler behaviour. Read a green run here as "the rename did not
+// break the ordinary path"; the claim it pins on the device is the CTS group above.
+
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        // The payload starts here and is copied, unmodified, through every block below.
+        const char* const kVertexSource = R"(#version 420 core
+out VsData {
+    vec4 payload;
+} vs_out;
+void main()
+{
+    vs_out.payload = vec4(0.0, 1.0, 0.0, 1.0);
+    gl_Position = vec4(0.0, 0.0, 0.0, 1.0);
+}
+)";
+
+        const char* const kTessControlSource = R"(#version 420 core
+layout(vertices = 1) out;
+in VsData {
+    vec4 payload;
+} tcs_in[];
+out TcsData {
+    vec4 payload;
+} tcs_out[];
+void main()
+{
+    tcs_out[gl_InvocationID].payload = tcs_in[gl_InvocationID].payload;
+    gl_TessLevelOuter[0] = 1.0;
+    gl_TessLevelOuter[1] = 1.0;
+    gl_TessLevelOuter[2] = 1.0;
+    gl_TessLevelOuter[3] = 1.0;
+    gl_TessLevelInner[0] = 1.0;
+    gl_TessLevelInner[1] = 1.0;
+}
+)";
+
+        // THE CASE UNDER TEST: one name, both directions, in one stage.
+        const char* const kCollidingTessEvalSource = R"(#version 420 core
+layout(isolines, point_mode) in;
+in TcsData {
+    vec4 payload;
+} tes_in[];
+out TcsData {
+    vec4 payload;
+} tes_out;
+out float tes_gs_alive;
+void main()
+{
+    tes_out.payload = tes_in[0].payload;
+    tes_gs_alive = 1.0;
+}
+)";
+
+        // The negative control: byte-identical but for the output block's name.
+        const char* const kDistinctTessEvalSource = R"(#version 420 core
+layout(isolines, point_mode) in;
+in TcsData {
+    vec4 payload;
+} tes_in[];
+out TesData {
+    vec4 payload;
+} tes_out;
+out float tes_gs_alive;
+void main()
+{
+    tes_out.payload = tes_in[0].payload;
+    tes_gs_alive = 1.0;
+}
+)";
+
+        // One geometry source per evaluation stage, because the block it consumes is named
+        // after the block the evaluation stage produced.
+        const char* const kCollidingGeometrySource = R"(#version 420 core
+layout(points) in;
+layout(triangle_strip, max_vertices = 4) out;
+in TcsData {
+    vec4 payload;
+} gs_in[];
+in float tes_gs_alive[];
+out GsData {
+    vec4 payload;
+} gs_out;
+out float gs_fs_alive;
+void EmitCorner(vec2 corner)
+{
+    gs_out.payload = gs_in[0].payload;
+    gs_fs_alive = tes_gs_alive[0];
+    gl_Position = vec4(corner, 0.0, 1.0);
+    EmitVertex();
+}
+void main()
+{
+    EmitCorner(vec2(-1.0, -1.0));
+    EmitCorner(vec2(-1.0,  1.0));
+    EmitCorner(vec2( 1.0, -1.0));
+    EmitCorner(vec2( 1.0,  1.0));
+}
+)";
+
+        const char* const kDistinctGeometrySource = R"(#version 420 core
+layout(points) in;
+layout(triangle_strip, max_vertices = 4) out;
+in TesData {
+    vec4 payload;
+} gs_in[];
+in float tes_gs_alive[];
+out GsData {
+    vec4 payload;
+} gs_out;
+out float gs_fs_alive;
+void EmitCorner(vec2 corner)
+{
+    gs_out.payload = gs_in[0].payload;
+    gs_fs_alive = tes_gs_alive[0];
+    gl_Position = vec4(corner, 0.0, 1.0);
+    EmitVertex();
+}
+void main()
+{
+    EmitCorner(vec2(-1.0, -1.0));
+    EmitCorner(vec2(-1.0,  1.0));
+    EmitCorner(vec2( 1.0, -1.0));
+    EmitCorner(vec2( 1.0,  1.0));
+}
+)";
+
+        // Red when the PLAIN varying did not arrive, so "the pipeline is broken" and "the
+        // block payload is broken" cannot be confused for one another.
+        const char* const kFragmentSource = R"(#version 420 core
+in GsData {
+    vec4 payload;
+} fs_in;
+in float gs_fs_alive;
+out vec4 fragColor;
+void main()
+{
+    fragColor = gs_fs_alive > 0.5 ? fs_in.payload : vec4(1.0, 0.0, 0.0, 1.0);
+}
+)";
+
+        class IoBlockNameCollisionScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                glGenVertexArrays(1, &m_vao);
+                glBindVertexArray(m_vao);
+                if (!BackendHostsTessellationAndGeometry()) {
+                    GTEST_SKIP() << "no tessellation/geometry stages on " << Gl().BackendName() << " ("
+                                 << Gl().RendererString() << "); there is no five-stage pipeline to "
+                                 << "carry a block through";
+                }
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                glUseProgram(0);
+                for (const GLuint program : m_programs) {
+                    glDeleteProgram(program);
+                }
+                m_programs.clear();
+                glBindVertexArray(0);
+                if (m_vao != 0) glDeleteVertexArrays(1, &m_vao);
+                m_vao = 0;
+            }
+
+            // GL_MAX_TESS_GEN_LEVEL is a real backend answer, not a frontend constant: it
+            // reads 0 on a DirectGLES driver without GL_EXT_tessellation_shader and on a
+            // DirectVulkan device without the tessellationShader feature. There is no
+            // five-stage pipeline to assert about on such a stack.
+            static bool BackendHostsTessellationAndGeometry() {
+                GLint maxTessGenLevel = 0;
+                glGetIntegerv(GL_MAX_TESS_GEN_LEVEL, &maxTessGenLevel);
+                GLint maxGeometryOutputVertices = 0;
+                glGetIntegerv(GL_MAX_GEOMETRY_OUTPUT_VERTICES, &maxGeometryOutputVertices);
+                while (glGetError() != GL_NO_ERROR) {
+                }
+                return maxTessGenLevel >= 1 && maxGeometryOutputVertices >= 4;
+            }
+
+            GLuint BuildPipeline(const char* tessEvalSource, const char* geometrySource) {
+                const GLenum stages[] = {GL_VERTEX_SHADER, GL_TESS_CONTROL_SHADER,
+                                         GL_TESS_EVALUATION_SHADER, GL_GEOMETRY_SHADER,
+                                         GL_FRAGMENT_SHADER};
+                const char* const sources[] = {kVertexSource, kTessControlSource, tessEvalSource,
+                                               geometrySource, kFragmentSource};
+
+                GLuint shaders[5] = {0, 0, 0, 0, 0};
+                bool ok = true;
+                for (int i = 0; i < 5; ++i) {
+                    shaders[i] = glCreateShader(stages[i]);
+                    glShaderSource(shaders[i], 1, &sources[i], nullptr);
+                    glCompileShader(shaders[i]);
+                    GLint compiled = 0;
+                    glGetShaderiv(shaders[i], GL_COMPILE_STATUS, &compiled);
+                    if (!compiled) {
+                        m_buildLog = InfoLog(shaders[i], true);
+                        ok = false;
+                        break;
+                    }
+                }
+                if (!ok) {
+                    for (const GLuint shader : shaders) {
+                        if (shader != 0) glDeleteShader(shader);
+                    }
+                    return 0;
+                }
+
+                const GLuint program = glCreateProgram();
+                for (const GLuint shader : shaders) {
+                    glAttachShader(program, shader);
+                }
+                glLinkProgram(program);
+                GLint linked = 0;
+                glGetProgramiv(program, GL_LINK_STATUS, &linked);
+                for (const GLuint shader : shaders) {
+                    glDeleteShader(shader);
+                }
+                if (!linked) {
+                    m_buildLog = InfoLog(program, false);
+                    glDeleteProgram(program);
+                    return 0;
+                }
+                m_programs.push_back(program);
+                return program;
+            }
+
+            // Clears to BLUE, so "the draw painted nothing" is a colour of its own rather
+            // than something that could be mistaken for a zeroed payload.
+            Rgba8 DrawAndReadCentre(GLuint program) const {
+                glViewport(0, 0, Gl().Width(), Gl().Height());
+                glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
+                glClear(GL_COLOR_BUFFER_BIT);
+                glUseProgram(program);
+                glPatchParameteri(GL_PATCH_VERTICES, 1);
+                glDrawArrays(GL_PATCHES, 0, 1);
+
+                Rgba8 pixel{};
+                glReadPixels(Gl().Width() / 2, Gl().Height() / 2, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &pixel);
+                return pixel;
+            }
+
+            static bool IsGreen(const Rgba8& pixel) {
+                return pixel.r < 64 && pixel.g > 192 && pixel.b < 64;
+            }
+
+            const std::string& BuildLog() const { return m_buildLog; }
+
+            static GLenum FirstGLError() {
+                const GLenum first = glGetError();
+                while (glGetError() != GL_NO_ERROR) {
+                }
+                return first;
+            }
+
+        private:
+            static std::string InfoLog(GLuint object, bool isShader) {
+                GLint length = 0;
+                if (isShader) {
+                    glGetShaderiv(object, GL_INFO_LOG_LENGTH, &length);
+                } else {
+                    glGetProgramiv(object, GL_INFO_LOG_LENGTH, &length);
+                }
+                std::vector<char> log(static_cast<std::size_t>(length > 1 ? length : 1), '\0');
+                if (isShader) {
+                    glGetShaderInfoLog(object, static_cast<GLsizei>(log.size()), nullptr, log.data());
+                } else {
+                    glGetProgramInfoLog(object, static_cast<GLsizei>(log.size()), nullptr, log.data());
+                }
+                return std::string(log.data());
+            }
+
+            GLuint m_vao = 0;
+            std::vector<GLuint> m_programs;
+            std::string m_buildLog;
+        };
+
+        // The negative control, and it runs first on purpose: if this one is not green there
+        // is nothing to conclude from the case below it.
+        //
+        // It is also the CALIBRATION. GL_MAX_TESS_GEN_LEVEL answers for the tessellation
+        // stages honestly, but nothing MobileGL reports answers for the geometry stage the
+        // same way (GL_MAX_GEOMETRY_* are frontend constants and an ES driver may legitimately
+        // report zero geometry storage blocks while having geometry shaders), so a stack that
+        // cannot build a five-stage program at all is recognised here, by trying.
+        TEST_F(IoBlockNameCollisionScenario, DistinctlyNamedBlocksCarryThePayloadThroughFiveStages) {
+            if (!Ready()) return;
+
+            const GLuint program = BuildPipeline(kDistinctTessEvalSource, kDistinctGeometrySource);
+            if (program == 0) {
+                GTEST_SKIP() << "this stack cannot build a five-stage tessellation+geometry program on "
+                             << Gl().BackendName() << ", so there is no block to carry through: "
+                             << BuildLog();
+            }
+
+            const Rgba8 centre = DrawAndReadCentre(program);
+            EXPECT_EQ(FirstGLError(), 0u);
+            EXPECT_TRUE(IsGreen(centre)) << "the control pipeline did not deliver its payload: " << centre;
+        }
+
+        TEST_F(IoBlockNameCollisionScenario, OneBlockNameInBothDirectionsStillCarriesThePayload) {
+            if (!Ready()) return;
+
+            // Same calibration as the case above, and for the same reason: a five-stage program
+            // this stack cannot build at all is not evidence about block names. Only once the
+            // DISTINCT-name build succeeds does a failure of the colliding one mean something.
+            if (BuildPipeline(kDistinctTessEvalSource, kDistinctGeometrySource) == 0) {
+                GTEST_SKIP() << "this stack cannot build a five-stage tessellation+geometry program on "
+                             << Gl().BackendName() << ", so there is no block to carry through: "
+                             << BuildLog();
+            }
+
+            // Legal desktop GLSL: input and output block names live in separate namespaces, so
+            // the evaluation stage below declares TcsData twice and must still compile. The
+            // control above having built is what makes this assertion about the NAME.
+            const GLuint program = BuildPipeline(kCollidingTessEvalSource, kCollidingGeometrySource);
+            ASSERT_NE(program, 0u)
+                << "an interface block name reused across the two directions of one stage is legal "
+                   "desktop GLSL, but the program did not build: "
+                << BuildLog();
+
+            const Rgba8 centre = DrawAndReadCentre(program);
+            EXPECT_EQ(FirstGLError(), 0u);
+            EXPECT_TRUE(IsGreen(centre))
+                << "the payload did not survive the stage that names its input and output block "
+                   "the same: "
+                << centre << " (blue: nothing drew; red: the plain varying was lost too; black: "
+                             "the block arrived empty)";
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/IterationRPFirstReductionScenario.cpp

@@ -0,0 +1,898 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/IterationRPFirstReductionScenario.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - ITERATIONRP'S FIRST SUBGROUP REDUCTION.
+//
+// iterationRP reduces a 32 x 16 exposure tile with a vector subgroup inclusive add,
+// then a shared-memory scan of subgroup totals.  The source assumes that every
+// subgroup has a last lane, that there are 2..32 subgroups, and that local index
+// 511 belongs to the last subgroup and its last lane.  Those are source assumptions,
+// not API contracts.  This probe intentionally does not repair them: it records the
+// observed topology and makes each handoff independently observable.
+
+#include <algorithm>
+#include <array>
+#include <bit>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <iomanip>
+#include <iostream>
+#include <limits>
+#include <sstream>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        constexpr std::size_t kInvocationCount = 512;
+        constexpr std::size_t kScanStageCount = 6;
+        constexpr std::uint32_t kQuietNanBits = 0x7fc00000u;
+        constexpr std::size_t kNoSlot = std::numeric_limits<std::size_t>::max();
+
+        struct UVec4 {
+            std::uint32_t x;
+            std::uint32_t y;
+            std::uint32_t z;
+            std::uint32_t w;
+        };
+
+        struct Vec4 {
+            float x;
+            float y;
+            float z;
+            float w;
+        };
+
+        // Matches the std430 block exactly. uvec4/vec4 arrays have a 16-byte
+        // stride, floats are a dense scalar array, and the outer scan array is
+        // stage-major in both GLSL and C++.
+        struct ProbeOutput {
+            std::array<UVec4, kInvocationCount> invocation;
+            std::array<UVec4, kInvocationCount> subgroup;
+            std::array<Vec4, kInvocationCount> reduction;
+            std::array<float, kInvocationCount> finalAverage;
+            std::array<std::array<float, kInvocationCount>, kScanStageCount> scanAfter;
+        };
+
+        static_assert(sizeof(UVec4) == 16);
+        static_assert(sizeof(Vec4) == 16);
+        static_assert(std::is_standard_layout_v<ProbeOutput>);
+        static_assert(offsetof(ProbeOutput, invocation) == 0);
+        static_assert(offsetof(ProbeOutput, subgroup) == 8192);
+        static_assert(offsetof(ProbeOutput, reduction) == 16384);
+        static_assert(offsetof(ProbeOutput, finalAverage) == 24576);
+        static_assert(offsetof(ProbeOutput, scanAfter) == 26624);
+        static_assert(sizeof(ProbeOutput) == 38912);
+
+        enum class InputMode {
+            SampledRgba32f,
+            IndexedSsbo,
+        };
+
+        const char* InputModeName(InputMode mode) {
+            return mode == InputMode::SampledRgba32f ? "sampled RGBA32F" : "indexed SSBO";
+        }
+
+        std::uint32_t FloatBits(float value) {
+            return std::bit_cast<std::uint32_t>(value);
+        }
+
+        bool SameBits(float lhs, float rhs) {
+            return FloatBits(lhs) == FloatBits(rhs);
+        }
+
+        bool IsQuietNanSentinel(float value) {
+            return FloatBits(value) == kQuietNanBits;
+        }
+
+        bool DrainGlErrors() {
+            bool hadError = false;
+            while (glGetError() != GL_NO_ERROR) hadError = true;
+            return hadError;
+        }
+
+        bool HasExtension(const char* wanted) {
+            GLint extensionCount = 0;
+            glGetIntegerv(GL_NUM_EXTENSIONS, &extensionCount);
+            for (GLint i = 0; i < extensionCount; ++i) {
+                const auto* extension = reinterpret_cast<const char*>(glGetStringi(GL_EXTENSIONS, static_cast<GLuint>(i)));
+                if (extension != nullptr && std::string(extension) == wanted) return true;
+            }
+            return false;
+        }
+
+        struct CapabilityInfo {
+            bool subgroupExtension = false;
+            GLint subgroupSize = 0;
+            GLint supportedStages = 0;
+            GLint supportedFeatures = 0;
+            GLint maxComputeStorageBlocks = 0;
+            GLint maxStorageBindings = 0;
+            GLint maxWorkGroupInvocations = 0;
+            std::array<GLint, 3> maxWorkGroupSize{};
+            bool queryHadError = false;
+
+            // iterationRP's source contract needs gl_NumSubgroups in [2, 32] for its 512
+            // invocations, i.e. an advertised subgroup width in [16, 256]. A device
+            // outside that window (lavapipe's 8-lane subgroups give 64 subgroups) cannot
+            // run the fixture's verbatim reduction at all, so the scenario SKIPS there -
+            // the pack itself replays through the FixIterationRPSubgroupScratch patch, which
+            // this probe deliberately does not model. The width only gates the domain;
+            // lane placement and group counts still come from observed values alone.
+            bool SubgroupWidthInSourceDomain() const {
+                return subgroupSize >= 16 && subgroupSize <= 256;
+            }
+
+            bool SupportsProbe() const {
+                const auto stages = static_cast<GLbitfield>(supportedStages);
+                const auto features = static_cast<GLbitfield>(supportedFeatures);
+                return !queryHadError && subgroupExtension &&
+                       (stages & GL_COMPUTE_SHADER_BIT) != 0 &&
+                       (features & (GL_SUBGROUP_FEATURE_BASIC_BIT_KHR | GL_SUBGROUP_FEATURE_ARITHMETIC_BIT_KHR)) ==
+                           (GL_SUBGROUP_FEATURE_BASIC_BIT_KHR | GL_SUBGROUP_FEATURE_ARITHMETIC_BIT_KHR) &&
+                       SubgroupWidthInSourceDomain() &&
+                       maxComputeStorageBlocks >= 2 && maxStorageBindings >= 2 &&
+                       maxWorkGroupInvocations >= static_cast<GLint>(kInvocationCount) && maxWorkGroupSize[0] >= 32 &&
+                       maxWorkGroupSize[1] >= 16 && maxWorkGroupSize[2] >= 1;
+            }
+
+            std::string MissingRequirements() const {
+                std::vector<std::string> missing;
+                const auto stages = static_cast<GLbitfield>(supportedStages);
+                const auto features = static_cast<GLbitfield>(supportedFeatures);
+                if (queryHadError) missing.emplace_back("a subgroup/compute capability query generated GL error");
+                if (!subgroupExtension) missing.emplace_back("GL_KHR_shader_subgroup");
+                if ((stages & GL_COMPUTE_SHADER_BIT) == 0) {
+                    missing.emplace_back("GL_COMPUTE_SHADER_BIT in GL_SUBGROUP_SUPPORTED_STAGES_KHR");
+                }
+                const auto requiredFeatures =
+                    GL_SUBGROUP_FEATURE_BASIC_BIT_KHR | GL_SUBGROUP_FEATURE_ARITHMETIC_BIT_KHR;
+                if ((features & requiredFeatures) != requiredFeatures) {
+                    missing.emplace_back("basic|arithmetic in GL_SUBGROUP_SUPPORTED_FEATURES_KHR");
+                }
+                if (!SubgroupWidthInSourceDomain()) {
+                    missing.emplace_back(
+                        "GL_SUBGROUP_SIZE_KHR in [16, 256] (iterationRP's source contract needs "
+                        "gl_NumSubgroups in [2, 32] for 512 invocations; width " +
+                        std::to_string(subgroupSize) + " is outside the fixture's domain)");
+                }
+                if (maxComputeStorageBlocks < 2 || maxStorageBindings < 2) {
+                    missing.emplace_back("two compute SSBO bindings");
+                }
+                if (maxWorkGroupInvocations < static_cast<GLint>(kInvocationCount) || maxWorkGroupSize[0] < 32 ||
+                    maxWorkGroupSize[1] < 16 || maxWorkGroupSize[2] < 1) {
+                    missing.emplace_back("a 32x16x1 / 512-invocation compute workgroup");
+                }
+
+                std::ostringstream message;
+                for (std::size_t i = 0; i < missing.size(); ++i) {
+                    if (i != 0) message << ", ";
+                    message << missing[i];
+                }
+                return message.str();
+            }
+        };
+
+        CapabilityInfo QueryCapabilities() {
+            CapabilityInfo info;
+            DrainGlErrors();
+            info.subgroupExtension = HasExtension("GL_KHR_shader_subgroup");
+            glGetIntegerv(GL_SUBGROUP_SIZE_KHR, &info.subgroupSize);
+            glGetIntegerv(GL_SUBGROUP_SUPPORTED_STAGES_KHR, &info.supportedStages);
+            glGetIntegerv(GL_SUBGROUP_SUPPORTED_FEATURES_KHR, &info.supportedFeatures);
+            glGetIntegerv(GL_MAX_COMPUTE_SHADER_STORAGE_BLOCKS, &info.maxComputeStorageBlocks);
+            glGetIntegerv(GL_MAX_SHADER_STORAGE_BUFFER_BINDINGS, &info.maxStorageBindings);
+            glGetIntegerv(GL_MAX_COMPUTE_WORK_GROUP_INVOCATIONS, &info.maxWorkGroupInvocations);
+            for (GLuint axis = 0; axis < info.maxWorkGroupSize.size(); ++axis) {
+                glGetIntegeri_v(GL_MAX_COMPUTE_WORK_GROUP_SIZE, axis, &info.maxWorkGroupSize[axis]);
+            }
+            info.queryHadError = DrainGlErrors();
+            return info;
+        }
+
+        void PrintMetadata(const CapabilityInfo& info, std::ostream& output) {
+            output << "IterationRPFirstReductionScenario metadata: "
+                   << "GL_SUBGROUP_SIZE_KHR=" << info.subgroupSize
+                   << ", GL_SUBGROUP_SUPPORTED_STAGES_KHR=0x" << std::hex
+                   << static_cast<GLbitfield>(info.supportedStages)
+                   << ", GL_SUBGROUP_SUPPORTED_FEATURES_KHR=0x"
+                   << static_cast<GLbitfield>(info.supportedFeatures) << std::dec
+                   << ", subgroupExtension=" << info.subgroupExtension
+                   << ", GL_MAX_COMPUTE_SHADER_STORAGE_BLOCKS=" << info.maxComputeStorageBlocks
+                   << ", GL_MAX_SHADER_STORAGE_BUFFER_BINDINGS=" << info.maxStorageBindings
+                   << ", GL_MAX_COMPUTE_WORK_GROUP_INVOCATIONS=" << info.maxWorkGroupInvocations
+                   << ", GL_MAX_COMPUTE_WORK_GROUP_SIZE=" << info.maxWorkGroupSize[0] << 'x'
+                   << info.maxWorkGroupSize[1] << 'x' << info.maxWorkGroupSize[2]
+                   << ", queryHadError=" << info.queryHadError << '\n';
+        }
+
+        bool DumpRequested() {
+            const char* value = std::getenv("MOBILEGL_ITEST_SUBGROUP_PROBE_DUMP");
+            return value != nullptr && std::string(value) == "1";
+        }
+
+        constexpr const char* kShaderPreamble = R"(#version 430 core
+#extension GL_KHR_shader_subgroup_basic : require
+#extension GL_KHR_shader_subgroup_arithmetic : require
+
+layout(local_size_x = 32, local_size_y = 16, local_size_z = 1) in;
+
+layout(std430, binding = 1) buffer SubgroupProbeOutput {
+    uvec4 invocation[512];
+    uvec4 subgroup[512];
+    vec4 reduction[512];
+    float finalAverage[512];
+    float scanAfter[6][512];
+} outProbe;
+
+shared vec2 prefixSumCache[32];
+)";
+
+        constexpr const char* kSampledInput = R"(
+uniform sampler2D colortex2;
+uniform vec2 pixelSize;
+)";
+
+        constexpr const char* kIndexedInput = R"(
+layout(std430, binding = 0) readonly buffer Input {
+    float value[512];
+} inputData;
+)";
+
+        // Only the expression producing tileExposure differs between the two
+        // tests. The remainder is the iterationRP first reduction, with stores
+        // placed after its existing barriers to expose each handoff.
+        constexpr const char* kSampledTileExposure = R"(
+    vec2 texCoord = (vec2(gl_GlobalInvocationID.xy) + 0.5) *
+                    vec2(1.0 / 32.0, 1.0 / 16.0);
+    vec2 sampleCoord = texCoord * (1.0 / 64.0);
+    sampleCoord.x += (15.0 / 32.0) + pixelSize.x * 12.0;
+
+    float tileExposure = dot(
+        textureLod(colortex2, sampleCoord, 0.0).rgb,
+        vec3(0.2125, 0.7154, 0.0721));
+)";
+
+        constexpr const char* kIndexedTileExposure = R"(
+    float tileExposure = inputData.value[gl_LocalInvocationIndex];
+)";
+
+        constexpr const char* kReductionBody = R"(
+    vec2 sampleLuminance = vec2(tileExposure, 0.0);
+    sampleLuminance = subgroupInclusiveAdd(sampleLuminance);
+    float nativeInclusive = sampleLuminance.x;
+
+    // This is a uniform, safety-only branch: it leaves an invalid source
+    // contract visible without indexing past the 32-entry cache or underflowing
+    // loopLength - 1. It is deliberately a failure on the CPU, not a skip.
+    bool sourceDomain = gl_NumSubgroups >= 2u && gl_NumSubgroups <= 32u;
+    if (!sourceDomain) {
+        float qNaN = uintBitsToFloat(0x7fc00000u);
+        uint localIndex = gl_LocalInvocationIndex;
+        outProbe.invocation[localIndex] = uvec4(localIndex, gl_LocalInvocationID);
+        outProbe.subgroup[localIndex] = uvec4(gl_SubgroupSize, gl_NumSubgroups, gl_SubgroupID,
+                                               gl_SubgroupInvocationID);
+        outProbe.reduction[localIndex] = vec4(tileExposure, nativeInclusive, qNaN, qNaN);
+        outProbe.finalAverage[localIndex] = qNaN;
+        for (uint stage = 0u; stage < 6u; ++stage)
+            outProbe.scanAfter[stage][localIndex] = qNaN;
+        return;
+    }
+
+    if (gl_SubgroupInvocationID == gl_SubgroupSize - 1u)
+        prefixSumCache[gl_SubgroupID] = sampleLuminance;
+    barrier();
+
+    float sourceRawSubtotal = prefixSumCache[gl_SubgroupID].x;
+
+    uint loopLength = uint(findMSB(gl_NumSubgroups));
+    loopLength += uint(gl_NumSubgroups - (1u << (loopLength - 1u)) > 0u);
+
+    for (uint scanStage = 0u; scanStage < loopLength; ++scanStage) {
+        if ((gl_SubgroupID & (1u << scanStage)) > 0u) {
+            sampleLuminance += prefixSumCache[(gl_SubgroupID >> scanStage << scanStage) - 1u];
+            if (gl_SubgroupInvocationID == gl_SubgroupSize - 1u)
+                prefixSumCache[gl_SubgroupID] = sampleLuminance;
+        }
+        barrier();
+        outProbe.scanAfter[scanStage][gl_LocalInvocationIndex] = sampleLuminance.x;
+    }
+
+    float sourceMergedPrefix = sampleLuminance.x;
+
+    if (gl_LocalInvocationIndex == 511u)
+        prefixSumCache[0] = sampleLuminance / 512.0;
+    barrier();
+
+    float avg = prefixSumCache[0].x;
+
+    uint localIndex = gl_LocalInvocationIndex;
+    outProbe.invocation[localIndex] = uvec4(localIndex, gl_LocalInvocationID);
+    outProbe.subgroup[localIndex] = uvec4(gl_SubgroupSize, gl_NumSubgroups, gl_SubgroupID,
+                                           gl_SubgroupInvocationID);
+    outProbe.reduction[localIndex] = vec4(tileExposure, nativeInclusive, sourceRawSubtotal, sourceMergedPrefix);
+    outProbe.finalAverage[localIndex] = avg;
+}
+)";
+
+        std::string BuildProbeShader(InputMode mode) {
+            std::string source = kShaderPreamble;
+            source += mode == InputMode::SampledRgba32f ? kSampledInput : kIndexedInput;
+            source += "\nvoid main() {\n";
+            source += mode == InputMode::SampledRgba32f ? kSampledTileExposure : kIndexedTileExposure;
+            source += kReductionBody;
+            return source;
+        }
+
+        std::string FormatFloat(float value) {
+            std::ostringstream text;
+            text << std::hexfloat << value;
+            return text.str();
+        }
+
+        struct ValidationResult {
+            bool ok = true;
+            std::string phase;
+            std::string message;
+            bool scanStageMismatch = false;
+            int scanStage = -1;
+            bool ownerEvaluated = false;
+            bool index511IsSourceLastLaneWriter = false;
+            bool index511IsHighestSubgroupMember = false;
+            std::uint32_t highestObservedSubgroup = 0;
+        };
+
+        ValidationResult Failure(std::string phase, std::string message) {
+            ValidationResult result;
+            result.ok = false;
+            result.phase = std::move(phase);
+            result.message = std::move(message);
+            return result;
+        }
+
+        constexpr float kSampledLuminance = 0.2125f + 0.7154f + 0.0721f;
+
+        float ExpectedInput(InputMode mode, std::uint32_t localIndex) {
+            return mode == InputMode::SampledRgba32f ? kSampledLuminance : static_cast<float>(localIndex + 1u);
+        }
+
+        ValidationResult ValidateProbe(const ProbeOutput& output, InputMode mode) {
+            std::array<std::size_t, kInvocationCount> slotForLocal{};
+            slotForLocal.fill(kNoSlot);
+
+            // 1. Record identity. Slots are only used to locate each reported
+            // local index; all subgroup behavior below groups recorded IDs/lanes.
+            for (std::size_t slot = 0; slot < kInvocationCount; ++slot) {
+                const std::uint32_t localIndex = output.invocation[slot].x;
+                if (localIndex >= kInvocationCount) {
+                    std::ostringstream message;
+                    message << "output slot " << slot << " reports localIndex " << localIndex << " outside [0, 511]";
+                    return Failure("record identity", message.str());
+                }
+                if (slotForLocal[localIndex] != kNoSlot) {
+                    std::ostringstream message;
+                    message << "localIndex " << localIndex << " appears in output slots " << slotForLocal[localIndex]
+                            << " and " << slot;
+                    return Failure("record identity", message.str());
+                }
+                slotForLocal[localIndex] = slot;
+            }
+            for (std::size_t localIndex = 0; localIndex < kInvocationCount; ++localIndex) {
+                if (slotForLocal[localIndex] == kNoSlot) {
+                    std::ostringstream message;
+                    message << "localIndex " << localIndex << " is missing from all 512 records";
+                    return Failure("record identity", message.str());
+                }
+            }
+            for (std::size_t localIndex = 0; localIndex < kInvocationCount; ++localIndex) {
+                const std::size_t slot = slotForLocal[localIndex];
+                const UVec4& invocation = output.invocation[slot];
+                const std::uint32_t expectedX = static_cast<std::uint32_t>(localIndex % 32u);
+                const std::uint32_t expectedY = static_cast<std::uint32_t>(localIndex / 32u);
+                if (invocation.y != expectedX || invocation.z != expectedY || invocation.w != 0u) {
+                    std::ostringstream message;
+                    message << "localIndex " << localIndex << " reports local invocation (" << invocation.y << ','
+                            << invocation.z << ',' << invocation.w << "), expected (" << expectedX << ',' << expectedY
+                            << ",0)";
+                    return Failure("record identity", message.str());
+                }
+                const float expectedInput = ExpectedInput(mode, static_cast<std::uint32_t>(localIndex));
+                const float actualInput = output.reduction[slot].x;
+                if (!SameBits(actualInput, expectedInput)) {
+                    std::ostringstream message;
+                    message << "localIndex " << localIndex << " input was " << FormatFloat(actualInput) << ", expected "
+                            << FormatFloat(expectedInput);
+                    return Failure("input", message.str());
+                }
+            }
+
+            // 2. Observed topology. Do not derive lanes or subgroup membership
+            // from local invocation indices: only the values the shader recorded
+            // participate in grouping.
+            const std::uint32_t reportedNumSubgroups = output.subgroup[slotForLocal[0]].y;
+            if (reportedNumSubgroups == 0u) {
+                return Failure("observed topology", "localIndex 0 reported gl_NumSubgroups == 0");
+            }
+            if (reportedNumSubgroups > kInvocationCount) {
+                std::ostringstream message;
+                message << "reported gl_NumSubgroups=" << reportedNumSubgroups
+                        << " exceeds the 512 recorded invocations, so at least one subgroup ID is missing";
+                return Failure("observed topology", message.str());
+            }
+            std::vector<std::vector<std::size_t>> subgroupSlots(reportedNumSubgroups);
+            for (std::size_t localIndex = 0; localIndex < kInvocationCount; ++localIndex) {
+                const std::size_t slot = slotForLocal[localIndex];
+                const UVec4& subgroup = output.subgroup[slot];
+                if (subgroup.x == 0u || subgroup.y == 0u) {
+                    std::ostringstream message;
+                    message << "localIndex " << localIndex << " reported subgroupSize=" << subgroup.x
+                            << ", numSubgroups=" << subgroup.y;
+                    return Failure("observed topology", message.str());
+                }
+                if (subgroup.y != reportedNumSubgroups) {
+                    std::ostringstream message;
+                    message << "localIndex " << localIndex << " reported numSubgroups=" << subgroup.y
+                            << ", while localIndex 0 reported " << reportedNumSubgroups;
+                    return Failure("observed topology", message.str());
+                }
+                if (subgroup.z >= reportedNumSubgroups) {
+                    std::ostringstream message;
+                    message << "localIndex " << localIndex << " reported subgroupID=" << subgroup.z
+                            << " outside [0, " << (reportedNumSubgroups - 1u) << ']';
+                    return Failure("observed topology", message.str());
+                }
+                if (subgroup.w >= subgroup.x) {
+                    std::ostringstream message;
+                    message << "localIndex " << localIndex << " reported laneID=" << subgroup.w
+                            << " outside its subgroupSize=" << subgroup.x;
+                    return Failure("observed topology", message.str());
+                }
+                subgroupSlots[subgroup.z].push_back(slot);
+            }
+            for (std::uint32_t subgroupID = 0; subgroupID < reportedNumSubgroups; ++subgroupID) {
+                if (subgroupSlots[subgroupID].empty()) {
+                    std::ostringstream message;
+                    message << "reported gl_NumSubgroups=" << reportedNumSubgroups
+                            << " but subgroupID " << subgroupID << " has no recorded members";
+                    return Failure("observed topology", message.str());
+                }
+                auto& members = subgroupSlots[subgroupID];
+                std::sort(members.begin(), members.end(), [&output](std::size_t lhs, std::size_t rhs) {
+                    return output.subgroup[lhs].w < output.subgroup[rhs].w;
+                });
+                for (std::size_t i = 1; i < members.size(); ++i) {
+                    if (output.subgroup[members[i - 1]].w == output.subgroup[members[i]].w) {
+                        std::ostringstream message;
+                        message << "subgroupID " << subgroupID << " contains duplicate laneID "
+                                << output.subgroup[members[i]].w;
+                        return Failure("observed topology", message.str());
+                    }
+                }
+            }
+
+            // 3. Native subgroup arithmetic, in the actual lane ordering emitted
+            // by the driver. The fixture values and all partial sums are exactly
+            // representable binary32 values, so compare representation, not epsilon.
+            std::array<float, kInvocationCount> nativePrefix{};
+            std::vector<float> nativeSubtotal(reportedNumSubgroups, 0.0f);
+            for (std::uint32_t subgroupID = 0; subgroupID < reportedNumSubgroups; ++subgroupID) {
+                float inclusive = 0.0f;
+                for (const std::size_t slot : subgroupSlots[subgroupID]) {
+                    const std::uint32_t localIndex = output.invocation[slot].x;
+                    inclusive += ExpectedInput(mode, localIndex);
+                    nativePrefix[slot] = inclusive;
+                    const float actualNative = output.reduction[slot].y;
+                    if (!SameBits(actualNative, inclusive)) {
+                        std::ostringstream message;
+                        message << "subgroupID " << subgroupID << ", laneID " << output.subgroup[slot].w
+                                << ", localIndex " << localIndex << " nativeInclusive was " << FormatFloat(actualNative)
+                                << ", expected " << FormatFloat(inclusive);
+                        return Failure("native subgroup arithmetic", message.str());
+                    }
+                }
+                nativeSubtotal[subgroupID] = inclusive;
+            }
+
+            // sourceDomain is the narrow source-side safety branch. It is checked
+            // after native arithmetic so an unsupported source topology still
+            // reports native subgroup behavior before failing explicitly.
+            if (reportedNumSubgroups < 2u || reportedNumSubgroups > 32u) {
+                for (std::size_t localIndex = 0; localIndex < kInvocationCount; ++localIndex) {
+                    const std::size_t slot = slotForLocal[localIndex];
+                    const Vec4& reduction = output.reduction[slot];
+                    if (!IsQuietNanSentinel(reduction.z) || !IsQuietNanSentinel(reduction.w) ||
+                        !IsQuietNanSentinel(output.finalAverage[slot])) {
+                        std::ostringstream message;
+                        message << "iterationRP source reduction has no valid contract for gl_NumSubgroups="
+                                << reportedNumSubgroups << "; localIndex " << localIndex
+                                << " did not preserve its qNaN source-reduction sentinel";
+                        return Failure("source domain", message.str());
+                    }
+                    for (std::size_t stage = 0; stage < kScanStageCount; ++stage) {
+                        if (!IsQuietNanSentinel(output.scanAfter[stage][slot])) {
+                            std::ostringstream message;
+                            message << "iterationRP source reduction has no valid contract for gl_NumSubgroups="
+                                    << reportedNumSubgroups << "; localIndex " << localIndex << ", scan stage " << stage
+                                    << " did not preserve its qNaN source-reduction sentinel";
+                            return Failure("source domain", message.str());
+                        }
+                    }
+                }
+                std::ostringstream message;
+                message << "iterationRP source reduction has no valid contract for observed gl_NumSubgroups="
+                        << reportedNumSubgroups << " (requires 2..32); native subgroup results were recorded";
+                return Failure("source domain", message.str());
+            }
+
+            // 4. iterationRP source writer and first shared-memory handoff.
+            std::vector<std::size_t> sourceWriter(reportedNumSubgroups, kNoSlot);
+            for (std::uint32_t subgroupID = 0; subgroupID < reportedNumSubgroups; ++subgroupID) {
+                std::size_t writerCount = 0;
+                for (const std::size_t slot : subgroupSlots[subgroupID]) {
+                    const UVec4& subgroup = output.subgroup[slot];
+                    if (subgroup.w == subgroup.x - 1u) {
+                        sourceWriter[subgroupID] = slot;
+                        ++writerCount;
+                    }
+                }
+                if (writerCount != 1u) {
+                    std::ostringstream message;
+                    message << "subgroupID " << subgroupID << " has " << writerCount
+                            << " recorded lane(s) where laneID == subgroupSize - 1; iterationRP leaves that "
+                               "shared-cache entry unwritten";
+                    return Failure("source writer", message.str());
+                }
+                for (const std::size_t slot : subgroupSlots[subgroupID]) {
+                    const float actualRawSubtotal = output.reduction[slot].z;
+                    if (!SameBits(actualRawSubtotal, nativeSubtotal[subgroupID])) {
+                        std::ostringstream message;
+                        message << "subgroupID " << subgroupID << ", localIndex " << output.invocation[slot].x
+                                << " sourceRawSubtotal was " << FormatFloat(actualRawSubtotal) << ", expected "
+                                << FormatFloat(nativeSubtotal[subgroupID]);
+                        return Failure("source raw subtotal", message.str());
+                    }
+                }
+            }
+
+            // 5. Reproduce the source loop exactly, including the redundant final
+            // scan iteration on power-of-two subgroup counts. Reads and writes in
+            // one iteration target disjoint cache entries, so update the cache at
+            // the CPU equivalent of the source barrier.
+            std::array<float, kInvocationCount> mergedPrefix = nativePrefix;
+            std::vector<float> cache = nativeSubtotal;
+            std::uint32_t loopLength = std::bit_width(reportedNumSubgroups) - 1u;
+            loopLength +=
+                static_cast<std::uint32_t>(reportedNumSubgroups - (1u << (loopLength - 1u)) > 0u);
+            for (std::uint32_t scanStage = 0u; scanStage < loopLength; ++scanStage) {
+                std::vector<float> cacheAfterStage = cache;
+                for (std::uint32_t subgroupID = 0; subgroupID < reportedNumSubgroups; ++subgroupID) {
+                    if ((subgroupID & (1u << scanStage)) == 0u) continue;
+                    const std::uint32_t sourceCacheIndex = (subgroupID >> scanStage << scanStage) - 1u;
+                    const float sourcePrefix = cache[sourceCacheIndex];
+                    for (const std::size_t slot : subgroupSlots[subgroupID]) {
+                        mergedPrefix[slot] += sourcePrefix;
+                    }
+                    cacheAfterStage[subgroupID] = mergedPrefix[sourceWriter[subgroupID]];
+                }
+                cache.swap(cacheAfterStage);
+                for (std::size_t localIndex = 0; localIndex < kInvocationCount; ++localIndex) {
+                    const std::size_t slot = slotForLocal[localIndex];
+                    const float actualAfterStage = output.scanAfter[scanStage][slot];
+                    if (!SameBits(actualAfterStage, mergedPrefix[slot])) {
+                        std::ostringstream message;
+                        message << "scanStage " << scanStage << ", subgroupID " << output.subgroup[slot].z
+                                << ", laneID " << output.subgroup[slot].w << ", localIndex " << localIndex
+                                << " scanAfter was " << FormatFloat(actualAfterStage) << ", expected "
+                                << FormatFloat(mergedPrefix[slot]);
+                        ValidationResult result = Failure("source scan", message.str());
+                        result.scanStageMismatch = true;
+                        result.scanStage = static_cast<int>(scanStage);
+                        return result;
+                    }
+                }
+            }
+            for (std::size_t localIndex = 0; localIndex < kInvocationCount; ++localIndex) {
+                const std::size_t slot = slotForLocal[localIndex];
+                const float actualMergedPrefix = output.reduction[slot].w;
+                if (!SameBits(actualMergedPrefix, mergedPrefix[slot])) {
+                    std::ostringstream message;
+                    message << "localIndex " << localIndex << " sourceMergedPrefix was "
+                            << FormatFloat(actualMergedPrefix) << ", expected " << FormatFloat(mergedPrefix[slot]);
+                    return Failure("source scan", message.str());
+                }
+            }
+
+            // 6. Final owner and average. The uniformity check is intentionally
+            // separate from the source's topology contract at local index 511.
+            const float firstAverage = output.finalAverage[slotForLocal[0]];
+            for (std::size_t localIndex = 1; localIndex < kInvocationCount; ++localIndex) {
+                const float actualAverage = output.finalAverage[slotForLocal[localIndex]];
+                if (!SameBits(actualAverage, firstAverage)) {
+                    std::ostringstream message;
+                    message << "finalAverage differs: localIndex 0 has " << FormatFloat(firstAverage)
+                            << ", localIndex " << localIndex << " has " << FormatFloat(actualAverage);
+                    return Failure("final average", message.str());
+                }
+            }
+
+            ValidationResult ownerResult;
+            ownerResult.ownerEvaluated = true;
+            for (std::uint32_t subgroupID = 0; subgroupID < reportedNumSubgroups; ++subgroupID) {
+                if (!subgroupSlots[subgroupID].empty()) {
+                    ownerResult.highestObservedSubgroup = std::max(ownerResult.highestObservedSubgroup, subgroupID);
+                }
+            }
+            const std::size_t index511Slot = slotForLocal[kInvocationCount - 1u];
+            const UVec4& index511Subgroup = output.subgroup[index511Slot];
+            ownerResult.index511IsSourceLastLaneWriter =
+                index511Subgroup.w == index511Subgroup.x - 1u;
+            ownerResult.index511IsHighestSubgroupMember =
+                index511Subgroup.z == ownerResult.highestObservedSubgroup;
+            if (!ownerResult.index511IsSourceLastLaneWriter || !ownerResult.index511IsHighestSubgroupMember) {
+                std::ostringstream message;
+                message << "iterationRP topology incompatibility: localIndex 511 is sourceLastLaneWriter="
+                        << ownerResult.index511IsSourceLastLaneWriter << ", highestSubgroupMember="
+                        << ownerResult.index511IsHighestSubgroupMember << " (subgroupID=" << index511Subgroup.z
+                        << ", highest observed subgroupID=" << ownerResult.highestObservedSubgroup << ')';
+                ownerResult.ok = false;
+                ownerResult.phase = "final average";
+                ownerResult.message = message.str();
+                return ownerResult;
+            }
+
+            float total = 0.0f;
+            for (const float subtotal : nativeSubtotal) total += subtotal;
+            float sampledExpectedTotal = 0.0f;
+            for (std::size_t i = 0; i < kInvocationCount; ++i) sampledExpectedTotal += kSampledLuminance;
+            const float expectedTotal = mode == InputMode::IndexedSsbo ? 131328.0f : sampledExpectedTotal;
+            if (!SameBits(total, expectedTotal) || !SameBits(mergedPrefix[index511Slot], expectedTotal)) {
+                std::ostringstream message;
+                message << "iterationRP source total was " << FormatFloat(mergedPrefix[index511Slot])
+                        << " (native total " << FormatFloat(total) << "), expected " << FormatFloat(expectedTotal);
+                ownerResult.ok = false;
+                ownerResult.phase = "final average";
+                ownerResult.message = message.str();
+                return ownerResult;
+            }
+
+            const float expectedAverage = mode == InputMode::IndexedSsbo ? 256.5f : sampledExpectedTotal / 512.0f;
+            if (!SameBits(firstAverage, expectedAverage)) {
+                std::ostringstream message;
+                message << "finalAverage was " << FormatFloat(firstAverage) << ", expected "
+                        << FormatFloat(expectedAverage);
+                ownerResult.ok = false;
+                ownerResult.phase = "final average";
+                ownerResult.message = message.str();
+                return ownerResult;
+            }
+            return ownerResult;
+        }
+
+        void DumpProbe(const ProbeOutput& output, const CapabilityInfo& capabilities, const ValidationResult& validation,
+                       bool includeScanStages) {
+            PrintMetadata(capabilities, std::cout);
+            if (validation.ok) {
+                std::cout << "IterationRPFirstReductionScenario firstFailure=none\n";
+            } else {
+                std::cout << "IterationRPFirstReductionScenario firstFailure=" << validation.phase << ": "
+                          << validation.message << '\n';
+            }
+            std::cout << "localIndex,localX,localY,localZ,subgroupSize,numSubgroups,subgroupID,laneID,input,"
+                         "nativeInclusive,subgroupSubtotal,mergedPrefix,finalAverage\n";
+            for (std::size_t slot = 0; slot < kInvocationCount; ++slot) {
+                const UVec4& invocation = output.invocation[slot];
+                const UVec4& subgroup = output.subgroup[slot];
+                const Vec4& reduction = output.reduction[slot];
+                std::cout << invocation.x << ',' << invocation.y << ',' << invocation.z << ',' << invocation.w << ','
+                          << subgroup.x << ',' << subgroup.y << ',' << subgroup.z << ',' << subgroup.w << ','
+                          << std::hexfloat << reduction.x << ',' << reduction.y << ',' << reduction.z << ','
+                          << reduction.w << ',' << output.finalAverage[slot] << std::defaultfloat << '\n';
+            }
+            if (includeScanStages) {
+                std::cout << "scanStage,localIndex,scanAfter\n";
+                for (std::size_t scanStage = 0; scanStage < kScanStageCount; ++scanStage) {
+                    for (std::size_t slot = 0; slot < kInvocationCount; ++slot) {
+                        std::cout << scanStage << ',' << output.invocation[slot].x << ',' << std::hexfloat
+                                  << output.scanAfter[scanStage][slot] << std::defaultfloat << '\n';
+                    }
+                }
+            }
+        }
+
+        class IterationRPFirstReductionScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+
+                m_capabilities = QueryCapabilities();
+                // GL_SUBGROUP_SIZE_KHR gates only whether the fixture's source contract
+                // can hold on this device (SubgroupWidthInSourceDomain); it is
+                // deliberately never used to infer lane placement or an expected group
+                // count - those come from observed values alone.
+                PrintMetadata(m_capabilities, std::cout);
+                RecordProperty("iterationrp_gl_subgroup_size_khr", std::to_string(m_capabilities.subgroupSize));
+                if (!m_capabilities.SupportsProbe()) {
+                    GTEST_SKIP() << "subgroup probe requires " << m_capabilities.MissingRequirements();
+                }
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                glUseProgram(0);
+                glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, 0);
+                glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, 0);
+                glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+                glActiveTexture(GL_TEXTURE3);
+                glBindTexture(GL_TEXTURE_2D, 0);
+                glActiveTexture(GL_TEXTURE0);
+                if (m_texture != 0) glDeleteTextures(1, &m_texture);
+                if (m_inputBuffer != 0) glDeleteBuffers(1, &m_inputBuffer);
+                if (m_outputBuffer != 0) glDeleteBuffers(1, &m_outputBuffer);
+                if (m_program != 0) glDeleteProgram(m_program);
+                m_texture = 0;
+                m_inputBuffer = 0;
+                m_outputBuffer = 0;
+                m_program = 0;
+            }
+
+            GLuint CompileComputeProgram(const std::string& source, std::string* outError) {
+                const char* text = source.c_str();
+                const GLuint shader = glCreateShader(GL_COMPUTE_SHADER);
+                if (shader == 0) {
+                    *outError = "glCreateShader(GL_COMPUTE_SHADER) returned 0";
+                    return 0;
+                }
+                glShaderSource(shader, 1, &text, nullptr);
+                glCompileShader(shader);
+                GLint compiled = GL_FALSE;
+                glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
+                if (compiled == GL_FALSE) {
+                    char log[8192] = {};
+                    glGetShaderInfoLog(shader, sizeof(log) - 1, nullptr, log);
+                    *outError = std::string("the subgroup probe compute shader did not compile: ") + log;
+                    glDeleteShader(shader);
+                    return 0;
+                }
+                const GLuint program = glCreateProgram();
+                glAttachShader(program, shader);
+                glLinkProgram(program);
+                glDeleteShader(shader);
+                GLint linked = GL_FALSE;
+                glGetProgramiv(program, GL_LINK_STATUS, &linked);
+                if (linked == GL_FALSE) {
+                    char log[8192] = {};
+                    glGetProgramInfoLog(program, sizeof(log) - 1, nullptr, log);
+                    *outError = std::string("the subgroup probe compute program did not link: ") + log;
+                    glDeleteProgram(program);
+                    return 0;
+                }
+                return program;
+            }
+
+            bool RunProbe(InputMode mode, ProbeOutput* output, std::string* outError) {
+                m_program = CompileComputeProgram(BuildProbeShader(mode), outError);
+                if (m_program == 0) return false;
+
+                ProbeOutput poison{};
+                std::memset(&poison, 0xa5, sizeof(poison));
+                glGenBuffers(1, &m_outputBuffer);
+                glBindBuffer(GL_SHADER_STORAGE_BUFFER, m_outputBuffer);
+                glBufferData(GL_SHADER_STORAGE_BUFFER, sizeof(ProbeOutput), &poison, GL_DYNAMIC_COPY);
+                glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, m_outputBuffer);
+
+                if (mode == InputMode::IndexedSsbo) {
+                    std::array<float, kInvocationCount> values{};
+                    for (std::size_t i = 0; i < values.size(); ++i) values[i] = static_cast<float>(i + 1u);
+                    glGenBuffers(1, &m_inputBuffer);
+                    glBindBuffer(GL_SHADER_STORAGE_BUFFER, m_inputBuffer);
+                    glBufferData(GL_SHADER_STORAGE_BUFFER, sizeof(values), values.data(), GL_STATIC_DRAW);
+                    glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, m_inputBuffer);
+                } else {
+                    constexpr std::array<float, 4> kOneTexel = {1.0f, 1.0f, 1.0f, 1.0f};
+                    glGenTextures(1, &m_texture);
+                    glActiveTexture(GL_TEXTURE3);
+                    glBindTexture(GL_TEXTURE_2D, m_texture);
+                    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+                    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+                    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+                    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+                    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, 1, 1, 0, GL_RGBA, GL_FLOAT, kOneTexel.data());
+                }
+
+                if (const GLenum error = FirstGLError(); error != GL_NO_ERROR) {
+                    std::ostringstream message;
+                    message << "subgroup probe resource setup left " << GLErrorName(error);
+                    *outError = message.str();
+                    return false;
+                }
+
+                glUseProgram(m_program);
+                if (mode == InputMode::SampledRgba32f) {
+                    const GLint sampler = glGetUniformLocation(m_program, "colortex2");
+                    const GLint pixelSize = glGetUniformLocation(m_program, "pixelSize");
+                    if (sampler == -1 || pixelSize == -1) {
+                        *outError = "the sampled probe uniforms were optimized away or not reflected";
+                        return false;
+                    }
+                    glUniform1i(sampler, 3);
+                    glUniform2f(pixelSize, 1.0f / 854.0f, 1.0f / 480.0f);
+                }
+                glDispatchCompute(1, 1, 1);
+                glMemoryBarrier(GL_ALL_BARRIER_BITS);
+                glBindBuffer(GL_SHADER_STORAGE_BUFFER, m_outputBuffer);
+                glGetBufferSubData(GL_SHADER_STORAGE_BUFFER, 0, sizeof(ProbeOutput), output);
+                if (const GLenum error = FirstGLError(); error != GL_NO_ERROR) {
+                    std::ostringstream message;
+                    message << "subgroup probe dispatch/readback left " << GLErrorName(error);
+                    *outError = message.str();
+                    return false;
+                }
+                return true;
+            }
+
+            void RunAndValidate(InputMode mode) {
+                ProbeOutput output{};
+                std::string error;
+                ASSERT_TRUE(RunProbe(mode, &output, &error)) << InputModeName(mode) << ": " << error;
+
+                const ValidationResult validation = ValidateProbe(output, mode);
+                if (validation.ownerEvaluated) {
+                    RecordProperty("iterationrp_index511_source_last_lane_writer",
+                                   validation.index511IsSourceLastLaneWriter ? "true" : "false");
+                    RecordProperty("iterationrp_index511_highest_subgroup_member",
+                                   validation.index511IsHighestSubgroupMember ? "true" : "false");
+                    RecordProperty("iterationrp_highest_observed_subgroup",
+                                   std::to_string(validation.highestObservedSubgroup));
+                    std::cout << "IterationRPFirstReductionScenario owner: localIndex511 sourceLastLaneWriter="
+                              << validation.index511IsSourceLastLaneWriter << ", highestSubgroupMember="
+                              << validation.index511IsHighestSubgroupMember << ", highestObservedSubgroup="
+                              << validation.highestObservedSubgroup << '\n';
+                }
+                if (!validation.ok || DumpRequested()) {
+                    DumpProbe(output, m_capabilities, validation, validation.scanStageMismatch || DumpRequested());
+                }
+                EXPECT_TRUE(validation.ok) << validation.phase << ": " << validation.message;
+            }
+
+            CapabilityInfo m_capabilities;
+            GLuint m_program = 0;
+            GLuint m_inputBuffer = 0;
+            GLuint m_outputBuffer = 0;
+            GLuint m_texture = 0;
+        };
+
+    } // namespace
+
+    TEST_F(IterationRPFirstReductionScenario, SampledRgba32fFirstAverage) {
+        if (!Ready() || IsSkipped()) return;
+        RunAndValidate(InputMode::SampledRgba32f);
+    }
+
+    TEST_F(IterationRPFirstReductionScenario, IndexedInputTopologyAndReduction) {
+        if (!Ready() || IsSkipped()) return;
+        RunAndValidate(InputMode::IndexedSsbo);
+    }
+
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/IterationRPProgram203Scenario.cpp

@@ -0,0 +1,379 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/IterationRPProgram203Scenario.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Full iterationRP Program 203 golden input/output fixture. The original shader
+// consumes deterministic complete textures and uniforms, then its complete
+// 512x513 RG16F output image is compared against fixed half-float golden bits.
+// This catches both a wrong exposure slot and collateral scratch corruption.
+
+#include <array>
+#include <bit>
+#include <cmath>
+#include <cstddef>
+#include <cstdint>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+        constexpr int kSceneWidth = 854;
+        constexpr int kSceneHeight = 480;
+        constexpr int kPixelDataWidth = 512;
+        constexpr int kPixelDataHeight = 513;
+        constexpr std::size_t kSceneTexelCount =
+            static_cast<std::size_t>(kSceneWidth) * kSceneHeight;
+        constexpr std::size_t kPixelDataTexelCount =
+            static_cast<std::size_t>(kPixelDataWidth) * kPixelDataHeight;
+
+        struct Rgba32f {
+            float r, g, b, a;
+        };
+
+        struct Rg16 {
+            std::uint16_t r, g;
+        };
+
+        static_assert(sizeof(Rgba32f) == 16);
+        static_assert(sizeof(Rg16) == 4);
+
+        // Captured from the fixed fixture on Adreno 830. These are the exact
+        // RG16F storage bits for (0.806640625, 8.2578125), not rounded decimal
+        // comparisons performed by the test.
+        constexpr Rg16 kGoldenExposure = {0x3a74u, 0x4821u};
+
+        constexpr const char* kCommonSource = R"glsl(
+#version 430 core
+#extension GL_KHR_shader_subgroup_arithmetic : require
+
+uniform int frameCounter;
+uniform float frameTime;
+uniform float aspectRatio;
+uniform vec2 pixelSize;
+uniform float nightVision;
+uniform float darknessLightFactor;
+uniform sampler2D colortex2;
+uniform sampler2D pixelData2D;
+layout(rg16f) uniform image2D img_pixelData2D;
+
+float remapSaturate(float x, float e0, float e1) {
+    return clamp((x - e0) / (e1 - e0), 0.0f, 1.0f);
+}
+
+float GetExposureValue(float luminance) {
+    float aeCurve = 0.65f;
+    aeCurve = mix(aeCurve, clamp(aeCurve * 1.2f, 0.0f, 1.0f), nightVision);
+    aeCurve *= remapSaturate(luminance, 2.0f, 1.0f) * 0.6f + 0.4f;
+    float ae = pow(luminance, -aeCurve);
+    ae *= 1.0f - min(darknessLightFactor * 2.0f, 0.9f);
+    ae *= 8.5f;
+    return ae;
+}
+)glsl";
+
+        constexpr const char* kOriginalMain = R"glsl(
+layout(local_size_x = 32, local_size_y = 16) in;
+shared vec2 prefixSumCache[32];
+
+void main() {
+    vec2 texCoord = (vec2(gl_GlobalInvocationID.xy) + 0.5f) * vec2(1.0f / 32.0f, 1.0f / 16.0f);
+    vec2 sampleCoord = texCoord * (1.0f / 64.0f);
+    sampleCoord.x += (15.0f / 32.0f) + pixelSize.x * 12.0f;
+    float tileExposure = dot(textureLod(colortex2, sampleCoord, 0.0f).rgb,
+                             vec3(0.2125f, 0.7154f, 0.0721f));
+    vec2 sampleLuminance = vec2(tileExposure, 0.0f);
+    sampleLuminance = subgroupInclusiveAdd(sampleLuminance);
+    if (gl_SubgroupInvocationID == gl_SubgroupSize - 1u)
+        prefixSumCache[gl_SubgroupID] = sampleLuminance;
+    barrier();
+
+    uint loopLength = uint(findMSB(gl_NumSubgroups));
+    loopLength += uint(gl_NumSubgroups - (1u << (loopLength - 1u)) > 0u);
+    for (uint i = 0u; i < loopLength; ++i) {
+        if ((gl_SubgroupID & (1u << i)) > 0u) {
+            sampleLuminance += prefixSumCache[(gl_SubgroupID >> i << i) - 1u];
+            if (gl_SubgroupInvocationID == gl_SubgroupSize - 1u)
+                prefixSumCache[gl_SubgroupID] = sampleLuminance;
+        }
+        barrier();
+    }
+    if (gl_LocalInvocationIndex == 511u)
+        prefixSumCache[0] = sampleLuminance / 512.0f;
+    barrier();
+
+    float avg = prefixSumCache[0].x;
+    vec2 tileDistance = texCoord * 2.0f - 1.0f;
+    tileDistance.y /= aspectRatio;
+    float centerDistance = length(tileDistance);
+    float tileWeight = remapSaturate(centerDistance, 0.6f, 0.4f);
+    tileExposure = max(7.0E-7f, tileExposure);
+    float lumaWeight = avg / tileExposure;
+    lumaWeight = pow(lumaWeight, remapSaturate(avg, 0.02f, 0.001f) * 0.4f + 0.2f);
+    tileWeight *= lumaWeight;
+
+    vec2 sampleExposure = vec2(tileExposure * tileWeight, tileWeight);
+    sampleExposure = subgroupInclusiveAdd(sampleExposure);
+    if (gl_SubgroupInvocationID == gl_SubgroupSize - 1u)
+        prefixSumCache[gl_SubgroupID] = sampleExposure;
+    barrier();
+    for (uint i = 0u; i < loopLength; ++i) {
+        if ((gl_SubgroupID & (1u << i)) > 0u) {
+            sampleExposure += prefixSumCache[(gl_SubgroupID >> i << i) - 1u];
+            if (gl_SubgroupInvocationID == gl_SubgroupSize - 1u)
+                prefixSumCache[gl_SubgroupID] = sampleExposure;
+        }
+        barrier();
+    }
+
+    if (gl_LocalInvocationIndex == 511u) {
+        float avgExposure = max(sampleExposure.x / sampleExposure.y * 29.3f, 1.0E-10f);
+        avgExposure = log2(avgExposure);
+        float prevAvgExposure = log2(texelFetch(pixelData2D, ivec2(0, 0), 0).x);
+        float frameTimeFixed = frameTime + step(frameCounter, 20) * 100.0f;
+        float exposureTime = clamp(frameTimeFixed * 2.0f, 0.0f, 1.0f);
+        avgExposure = mix(prevAvgExposure, avgExposure, exposureTime);
+        avgExposure = max(exp2(avgExposure), 1.0E-5f);
+        float exposure = GetExposureValue(avgExposure);
+        imageStore(img_pixelData2D, ivec2(0, 0), vec4(avgExposure, exposure, 0.0f, 0.0f));
+    }
+}
+)glsl";
+
+        GLuint CompileCompute(const char* mainSource, std::string* error) {
+            const std::array<const GLchar*, 2> sources = {kCommonSource, mainSource};
+            const GLuint shader = glCreateShader(GL_COMPUTE_SHADER);
+            glShaderSource(shader, static_cast<GLsizei>(sources.size()), sources.data(), nullptr);
+            glCompileShader(shader);
+            GLint compiled = GL_FALSE;
+            glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
+            if (compiled != GL_TRUE) {
+                std::array<char, 8192> log{};
+                glGetShaderInfoLog(shader, static_cast<GLsizei>(log.size() - 1), nullptr, log.data());
+                *error = log.data();
+                glDeleteShader(shader);
+                return 0;
+            }
+            const GLuint program = glCreateProgram();
+            glAttachShader(program, shader);
+            glLinkProgram(program);
+            glDeleteShader(shader);
+            GLint linked = GL_FALSE;
+            glGetProgramiv(program, GL_LINK_STATUS, &linked);
+            if (linked != GL_TRUE) {
+                std::array<char, 8192> log{};
+                glGetProgramInfoLog(program, static_cast<GLsizei>(log.size() - 1), nullptr, log.data());
+                *error = log.data();
+                glDeleteProgram(program);
+                return 0;
+            }
+            return program;
+        }
+
+        std::vector<Rgba32f> MakeSceneInput() {
+            std::vector<Rgba32f> texels(kSceneTexelCount);
+            for (int y = 0; y < kSceneHeight; ++y) {
+                for (int x = 0; x < kSceneWidth; ++x) {
+                    std::uint32_t h = static_cast<std::uint32_t>(x) * 0x9e3779b9u;
+                    h ^= static_cast<std::uint32_t>(y) * 0x85ebca6bu;
+                    h ^= h >> 16u;
+                    h *= 0x7feb352du;
+                    h ^= h >> 15u;
+                    const float noise = static_cast<float>(h & 0xffffu) / 65535.0f;
+                    float base = 0.0002f + noise * 0.075f;
+                    const float dx = static_cast<float>(x - 420);
+                    const float dy = static_cast<float>(y - 4);
+                    base += 0.65f * std::exp(-(dx * dx + dy * dy) / 18.0f);
+                    if (((x + y * 17) % 113) == 0) base += 1.75f;
+                    texels[static_cast<std::size_t>(y) * kSceneWidth + x] =
+                        {base * 0.83f, base * 1.07f, base * 1.31f, 1.0f};
+                }
+            }
+            return texels;
+        }
+
+        std::uint16_t FloatToHalf(float value) {
+            const std::uint32_t bits = std::bit_cast<std::uint32_t>(value);
+            const std::uint32_t sign = (bits >> 16u) & 0x8000u;
+            const std::uint32_t exponent = (bits >> 23u) & 0xffu;
+            std::uint32_t mantissa = bits & 0x7fffffu;
+
+            if (exponent == 0xffu) {
+                return static_cast<std::uint16_t>(sign | (mantissa == 0 ? 0x7c00u : 0x7e00u));
+            }
+            int halfExponent = static_cast<int>(exponent) - 127 + 15;
+            if (halfExponent >= 31) return static_cast<std::uint16_t>(sign | 0x7c00u);
+            if (halfExponent <= 0) {
+                if (halfExponent < -10) return static_cast<std::uint16_t>(sign);
+                mantissa |= 0x800000u;
+                const unsigned shift = static_cast<unsigned>(14 - halfExponent);
+                const std::uint32_t rounded = mantissa + ((1u << (shift - 1u)) - 1u) +
+                                              ((mantissa >> shift) & 1u);
+                return static_cast<std::uint16_t>(sign | (rounded >> shift));
+            }
+            mantissa += 0xfffu + ((mantissa >> 13u) & 1u);
+            if ((mantissa & 0x800000u) != 0) {
+                mantissa = 0;
+                if (++halfExponent >= 31) return static_cast<std::uint16_t>(sign | 0x7c00u);
+            }
+            return static_cast<std::uint16_t>(sign | (static_cast<std::uint32_t>(halfExponent) << 10u) |
+                                              (mantissa >> 13u));
+        }
+
+        std::vector<Rg16> MakePixelDataInput() {
+            std::vector<Rg16> texels(kPixelDataTexelCount);
+            for (std::size_t i = 0; i < texels.size(); ++i) {
+                texels[i] = {FloatToHalf(0.35f + static_cast<float>(i % 97u) * 0.0025f),
+                             FloatToHalf(-0.45f + static_cast<float>(i % 89u) * 0.01f)};
+            }
+            texels[0] = {FloatToHalf(0.73f), FloatToHalf(1.25f)};
+            return texels;
+        }
+
+        std::vector<Rg16> MakeGoldenOutput() {
+            std::vector<Rg16> golden = MakePixelDataInput();
+            golden[0] = kGoldenExposure;
+            return golden;
+        }
+
+        GLuint MakeTexture(GLenum internalFormat, GLenum format, GLenum type, int width, int height,
+                           const void* data) {
+            GLuint texture = 0;
+            glGenTextures(1, &texture);
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+            glTexImage2D(GL_TEXTURE_2D, 0, static_cast<GLint>(internalFormat), width, height, 0, format,
+                         type, data);
+            return texture;
+        }
+
+        void BindAndDispatch(GLuint program, GLuint scene, GLuint pixelData) {
+            glUseProgram(program);
+            glActiveTexture(GL_TEXTURE3);
+            glBindTexture(GL_TEXTURE_2D, scene);
+            glUniform1i(glGetUniformLocation(program, "colortex2"), 3);
+            glActiveTexture(GL_TEXTURE4);
+            glBindTexture(GL_TEXTURE_2D, pixelData);
+            glUniform1i(glGetUniformLocation(program, "pixelData2D"), 4);
+            glBindImageTexture(0, pixelData, 0, GL_FALSE, 0, GL_READ_WRITE, GL_RG16F);
+            glUniform1i(glGetUniformLocation(program, "img_pixelData2D"), 0);
+            glUniform1i(glGetUniformLocation(program, "frameCounter"), 100);
+            glUniform1f(glGetUniformLocation(program, "frameTime"), 1.0f / 60.0f);
+            glUniform1f(glGetUniformLocation(program, "aspectRatio"),
+                        static_cast<float>(kSceneWidth) / kSceneHeight);
+            glUniform2f(glGetUniformLocation(program, "pixelSize"), 1.0f / kSceneWidth, 1.0f / kSceneHeight);
+            glUniform1f(glGetUniformLocation(program, "nightVision"), 0.23f);
+            glUniform1f(glGetUniformLocation(program, "darknessLightFactor"), 0.08f);
+            glDispatchCompute(1, 1, 1);
+            glMemoryBarrier(GL_TEXTURE_UPDATE_BARRIER_BIT | GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
+        }
+
+        std::vector<Rg16> ReadWholeRgTexture(GLuint texture) {
+            std::vector<Rg16> texels(kPixelDataTexelCount);
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glGetTexImage(GL_TEXTURE_2D, 0, GL_RG, GL_HALF_FLOAT, texels.data());
+            return texels;
+        }
+
+        class IterationRPProgram203Scenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+
+                GLint stages = 0;
+                GLint features = 0;
+                GLint invocations = 0;
+                glGetIntegerv(GL_SUBGROUP_SUPPORTED_STAGES_KHR, &stages);
+                glGetIntegerv(GL_SUBGROUP_SUPPORTED_FEATURES_KHR, &features);
+                glGetIntegerv(GL_MAX_COMPUTE_WORK_GROUP_INVOCATIONS, &invocations);
+                const GLbitfield required =
+                    GL_SUBGROUP_FEATURE_BASIC_BIT_KHR | GL_SUBGROUP_FEATURE_ARITHMETIC_BIT_KHR;
+                if ((static_cast<GLbitfield>(stages) & GL_COMPUTE_SHADER_BIT) == 0 ||
+                    (static_cast<GLbitfield>(features) & required) != required || invocations < 512) {
+                    GTEST_SKIP() << "requires 512-invocation basic+arithmetic compute subgroups";
+                }
+
+                std::string error;
+                m_original = CompileCompute(kOriginalMain, &error);
+                ASSERT_NE(m_original, 0u) << "original Program 203: " << error;
+
+                const std::vector<Rgba32f> scene = MakeSceneInput();
+                const std::vector<Rg16> pixelData = MakePixelDataInput();
+                m_scene = MakeTexture(GL_RGBA16F, GL_RGBA, GL_FLOAT, kSceneWidth, kSceneHeight, scene.data());
+                m_originalOutput =
+                    MakeTexture(GL_RG16F, GL_RG, GL_HALF_FLOAT, kPixelDataWidth, kPixelDataHeight,
+                                pixelData.data());
+                ASSERT_EQ(FirstGLError(), static_cast<GLenum>(GL_NO_ERROR));
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                const std::array<GLuint, 2> textures = {m_scene, m_originalOutput};
+                glDeleteTextures(static_cast<GLsizei>(textures.size()), textures.data());
+                if (m_original != 0) glDeleteProgram(m_original);
+            }
+
+            GLuint m_original = 0;
+            GLuint m_scene = 0;
+            GLuint m_originalOutput = 0;
+        };
+    } // namespace
+
+    TEST_F(IterationRPProgram203Scenario, FixedCompleteInputProducesFixedCompleteGoldenOutput) {
+        if (!Ready()) return;
+
+        BindAndDispatch(m_original, m_scene, m_originalOutput);
+        glFinish();
+        const std::vector<Rg16> actual = ReadWholeRgTexture(m_originalOutput);
+        const std::vector<Rg16> expected = MakeGoldenOutput();
+        ASSERT_EQ(FirstGLError(), static_cast<GLenum>(GL_NO_ERROR));
+
+        std::size_t mismatchTexels = 0;
+        std::size_t firstMismatch = actual.size();
+        for (std::size_t i = 0; i < actual.size(); ++i) {
+            if (actual[i].r != expected[i].r || actual[i].g != expected[i].g) {
+                if (firstMismatch == actual.size()) firstMismatch = i;
+                ++mismatchTexels;
+            }
+        }
+
+        RecordProperty("program203_output_width", kPixelDataWidth);
+        RecordProperty("program203_output_height", kPixelDataHeight);
+        RecordProperty("program203_compared_texels", static_cast<long long>(actual.size()));
+        RecordProperty("program203_mismatch_texels", static_cast<long long>(mismatchTexels));
+        std::cout << "IterationRPProgram203Scenario complete-output actualExposureBits=(0x" << std::hex
+                  << actual[0].r << ", 0x" << actual[0].g << ") goldenExposureBits=(0x" << expected[0].r
+                  << ", 0x" << expected[0].g << std::dec << ") mismatches=" << mismatchTexels << '/'
+                  << actual.size() << '\n';
+
+        if (firstMismatch != actual.size()) {
+            const std::size_t x = firstMismatch % kPixelDataWidth;
+            const std::size_t y = firstMismatch / kPixelDataWidth;
+            ADD_FAILURE() << "complete Program 203 output differs at " << x << ',' << y
+                          << ": actual half bits=(0x" << std::hex << actual[firstMismatch].r << ", 0x"
+                          << actual[firstMismatch].g << ") golden half bits=(0x" << expected[firstMismatch].r
+                          << ", 0x" << expected[firstMismatch].g << std::dec << "); mismatched "
+                          << mismatchTexels << " of " << actual.size() << " texels";
+        }
+        EXPECT_EQ(mismatchTexels, 0u);
+    }
+} // namespace MGITest