[Fix] (DirectGLES): lower gl_ClipDistance for Adreno's ESSL compiler - shadow the builtin in a Private array with constant-index flushes before EmitVertex/return, loop-copy gl_in clip distances through dynamic indices (whole-array reads segfault the Qualcomm compiler, constant-index element reads miscompile), strip the SPIRV-Cross redeclaration Adreno rejects, and split const struct-array LUT initializers so they stay dynamically indexable; quirk-gated to Qualcomm with MOBILEGL_QUIRK_CLIP_DISTANCE override

- SyncCurrentFBO skips the READ-target pass when the same GL FBO is bound as
  both draw and read (the common GL_FRAMEBUFFER case), but the read buffer
  (glReadBuffer) is only applied inside SyncToBackend's READ path — so the skip
  silently dropped every glReadBuffer change, leaving the backend read buffer
  stuck at COLOR_ATTACHMENT0.
- Extract the read-buffer application into BackendFramebufferObject::
  SyncReadBufferToBackend and invoke it from the skip branch (target == Read)
  as well as from SyncToBackend, so reads always target the right attachment.
- Bind the backend FBO as READ inside the helper before glReadBuffer, since the
  skip path only bound it as DRAW.
- Fixes KHR-GL3x.draw_buffers.draw_buffers_1 (reading COLOR_ATTACHMENT1 while
  the FBO stays GL_FRAMEBUFFER-bound returned attachment 0's value); the render
  was already correct, only the readback resolved the wrong attachment.

.github/scripts/fetch-trace-fixture-lfs.sh

@@ -9,17 +9,45 @@ fi
 case_name="$1"
 fixture_dir="${2:-tools/trace_replay/fixtures}"
 python_bin="${PYTHON:-python3}"
-mirror_base="${MOBILEGL_TRACE_FIXTURE_MIRROR_BASE:-https://repo.miawa.cn/mgl/tools/trace_replay/fixtures}"
+# Fixture mirrors, tried in order before falling back to Git LFS. Override the
+# whole list with MOBILEGL_TRACE_FIXTURE_MIRROR_BASES (whitespace separated);
+# MOBILEGL_TRACE_FIXTURE_MIRROR_BASE still works and is tried first.
+default_mirror_bases=(
+  "https://git.hit.moe/swung0x48/MobileGL/media/branch/dev/tools/trace_replay/fixtures"
+  "https://repo.miawa.cn/mgl/tools/trace_replay/fixtures"
+)
+if [ -n "${MOBILEGL_TRACE_FIXTURE_MIRROR_BASES:-}" ]; then
+  read -r -a mirror_bases <<< "${MOBILEGL_TRACE_FIXTURE_MIRROR_BASES}"
+else
+  mirror_bases=("${default_mirror_bases[@]}")
+fi
+if [ -n "${MOBILEGL_TRACE_FIXTURE_MIRROR_BASE:-}" ]; then
+  mirror_bases=("${MOBILEGL_TRACE_FIXTURE_MIRROR_BASE}" "${mirror_bases[@]}")
+fi
+# Optional bearer token for mirrors that require authentication (private Gitea).
+mirror_token="${MOBILEGL_TRACE_FIXTURE_MIRROR_TOKEN:-}"
+download_attempts="${MOBILEGL_TRACE_FIXTURE_DOWNLOAD_ATTEMPTS:-5}"
+retry_delay="${MOBILEGL_TRACE_FIXTURE_RETRY_DELAY:-2}"
 
 if ! command -v "${python_bin}" >/dev/null 2>&1 && command -v python >/dev/null 2>&1; then
   python_bin=python
 fi
 
+if ! [[ "${download_attempts}" =~ ^[1-9][0-9]*$ ]]; then
+  echo "MOBILEGL_TRACE_FIXTURE_DOWNLOAD_ATTEMPTS must be a positive integer: ${download_attempts}" >&2
+  exit 2
+fi
+if ! [[ "${retry_delay}" =~ ^[0-9]+$ ]]; then
+  echo "MOBILEGL_TRACE_FIXTURE_RETRY_DELAY must be a non-negative integer: ${retry_delay}" >&2
+  exit 2
+fi
+
 fixture_list="$("${python_bin}" tools/trace_replay/trace_cases.py \
   --format fixture-files \
   --case "${case_name}" \
   --fixture-root "${fixture_dir}")"
-mapfile -t files <<< "${fixture_list}"
+# Strip CR so the script also works when python emits CRLF (Git Bash on Windows).
+mapfile -t files < <(printf '%s\n' "${fixture_list}" | tr -d '\r')
 
 include="$(IFS=,; echo "${files[*]}")"
 if [ "${case_name}" = "OpenRA" ]; then
@@ -34,34 +62,178 @@ if [ "${case_name}" = "OpenRA" ]; then
   exit 0
 fi
 
+get_lfs_metadata() {
+  local file="$1"
+  local pointer
+  local expected_oid
+  local expected_size
+
+  if ! pointer="$(git show "HEAD:${file}" 2>/dev/null)"; then
+    echo "failed to read tracked fixture metadata: ${file}" >&2
+    return 1
+  fi
+  if ! grep -q '^version https://git-lfs.github.com/spec/v1$' <<< "${pointer}"; then
+    echo "tracked fixture is not a Git LFS pointer: ${file}" >&2
+    return 1
+  fi
+
+  expected_oid="$(awk '$1 == "oid" && $2 ~ /^sha256:/ { sub(/^sha256:/, "", $2); print $2 }' <<< "${pointer}")"
+  expected_size="$(awk '$1 == "size" { print $2 }' <<< "${pointer}")"
+  if ! [[ "${expected_oid}" =~ ^[0-9a-f]{64}$ ]] || ! [[ "${expected_size}" =~ ^[0-9]+$ ]]; then
+    echo "invalid Git LFS pointer metadata: ${file}" >&2
+    return 1
+  fi
+
+  printf '%s %s\n' "${expected_oid}" "${expected_size}"
+}
+
+verify_fixture_file() {
+  local downloaded_file="$1"
+  local display_name="$2"
+  local expected_oid="$3"
+  local expected_size="$4"
+  local actual_oid
+  local actual_size
+
+  if [ ! -f "${downloaded_file}" ]; then
+    echo "fixture file is missing: ${display_name}" >&2
+    return 1
+  fi
+
+  actual_size="$(wc -c < "${downloaded_file}" | tr -d '[:space:]')"
+  if [ "${actual_size}" != "${expected_size}" ]; then
+    echo "fixture size mismatch for ${display_name}: expected ${expected_size}, got ${actual_size}" >&2
+    return 1
+  fi
+
+  actual_oid="$(sha256sum "${downloaded_file}" | awk '{ print $1 }')"
+  if [ "${actual_oid}" != "${expected_oid}" ]; then
+    echo "fixture SHA-256 mismatch for ${display_name}: expected ${expected_oid}, got ${actual_oid}" >&2
+    return 1
+  fi
+}
+
+fetch_file_from_mirror() {
+  local file="$1"
+  local url="$2"
+  local metadata
+  local expected_oid
+  local expected_size
+  local tmp_file="${file}.tmp"
+  local attempt
+  local partial_size
+  local curl_status
+  local curl_auth
+
+  metadata="$(get_lfs_metadata "${file}")" || return 1
+  read -r expected_oid expected_size <<< "${metadata}"
+
+  if [ -f "${tmp_file}" ]; then
+    partial_size="$(wc -c < "${tmp_file}" | tr -d '[:space:]')"
+    if [ "${partial_size}" -gt "${expected_size}" ]; then
+      echo "Discarding oversized partial fixture ${tmp_file}: ${partial_size} > ${expected_size}" >&2
+      rm -f "${tmp_file}"
+    elif [ "${partial_size}" = "${expected_size}" ]; then
+      if verify_fixture_file "${tmp_file}" "${file}" "${expected_oid}" "${expected_size}"; then
+        mv "${tmp_file}" "${file}"
+        return 0
+      fi
+      rm -f "${tmp_file}"
+    fi
+  fi
+
+  for ((attempt = 1; attempt <= download_attempts; attempt++)); do
+    partial_size=0
+    if [ -f "${tmp_file}" ]; then
+      partial_size="$(wc -c < "${tmp_file}" | tr -d '[:space:]')"
+    fi
+
+    if [ "${partial_size}" -gt 0 ]; then
+      echo "Resuming mirror download for ${file} at byte ${partial_size} (attempt ${attempt}/${download_attempts})"
+    else
+      echo "Starting mirror download for ${file} (attempt ${attempt}/${download_attempts})"
+    fi
+
+    curl_auth=()
+    if [ -n "${mirror_token}" ]; then
+      curl_auth=(--header "Authorization: token ${mirror_token}")
+    fi
+    if curl -L --fail --show-error --continue-at - "${curl_auth[@]}" --output "${tmp_file}" "${url}"; then
+      if verify_fixture_file "${tmp_file}" "${file}" "${expected_oid}" "${expected_size}"; then
+        mv "${tmp_file}" "${file}"
+        return 0
+      fi
+      echo "Mirror download failed integrity verification; retrying from the beginning: ${file}" >&2
+      rm -f "${tmp_file}"
+    else
+      curl_status=$?
+      partial_size=0
+      if [ -f "${tmp_file}" ]; then
+        partial_size="$(wc -c < "${tmp_file}" | tr -d '[:space:]')"
+      fi
+
+      if [ "${partial_size}" = "${expected_size}" ]; then
+        if verify_fixture_file "${tmp_file}" "${file}" "${expected_oid}" "${expected_size}"; then
+          mv "${tmp_file}" "${file}"
+          return 0
+        fi
+        rm -f "${tmp_file}"
+        partial_size=0
+      elif [ "${partial_size}" -gt "${expected_size}" ]; then
+        echo "Discarding oversized partial fixture ${tmp_file}: ${partial_size} > ${expected_size}" >&2
+        rm -f "${tmp_file}"
+        partial_size=0
+      elif [ "${curl_status}" -eq 33 ]; then
+        echo "Mirror refused the resume request; retrying from the beginning: ${file}" >&2
+        rm -f "${tmp_file}"
+        partial_size=0
+      fi
+
+      echo "Mirror download attempt ${attempt}/${download_attempts} failed with curl exit ${curl_status}; retained ${partial_size} bytes for resume: ${file}" >&2
+    fi
+
+    if [ "${attempt}" -lt "${download_attempts}" ]; then
+      sleep "${retry_delay}"
+    fi
+  done
+
+  rm -f "${tmp_file}"
+  return 1
+}
+
 fetch_from_mirror() {
   mkdir -p "${fixture_dir}"
   for file in "${files[@]}"; do
     local name
     local url
+    local base
+    local fetched=0
     name="$(basename "${file}")"
-    url="${mirror_base%/}/${name}"
-    echo "Fetching trace fixture from mirror: ${url}"
-    if ! curl -L --fail --retry 3 --retry-delay 2 -o "${file}.tmp" "${url}"; then
-      rm -f "${file}.tmp"
+    for base in "${mirror_bases[@]}"; do
+      url="${base%/}/${name}"
+      echo "Fetching trace fixture from mirror: ${url}"
+      if fetch_file_from_mirror "${file}" "${url}"; then
+        fetched=1
+        break
+      fi
+      echo "Mirror did not serve ${name}; trying the next mirror" >&2
+    done
+    if [ "${fetched}" -ne 1 ]; then
       return 1
     fi
-    mv "${file}.tmp" "${file}"
   done
 }
 
 if fetch_from_mirror; then
   echo "Fetched trace fixture files for ${case_name} from mirror: ${include}"
 else
-  echo "Mirror fetch failed for ${case_name}; falling back to Git LFS: ${include}"
+  echo "All mirrors failed for ${case_name}; falling back to Git LFS: ${include}"
   git lfs install --local
   git lfs pull --include="${include}" --exclude=""
 fi
 
 for file in "${files[@]}"; do
-  test -s "${file}"
-  if head -n 1 "${file}" | grep -q "version https://git-lfs.github.com/spec/v1"; then
-    echo "failed to hydrate LFS fixture: ${file}" >&2
-    exit 1
-  fi
+  metadata="$(get_lfs_metadata "${file}")"
+  read -r expected_oid expected_size <<< "${metadata}"
+  verify_fixture_file "${file}" "${file}" "${expected_oid}" "${expected_size}"
 done

.github/workflows/apk.yml

@@ -227,6 +227,8 @@ jobs:
     env:
       AVD_NAME: mobilegl-ci
       ANDROID_AVD_HOME: ${{ github.workspace }}/.android/avd
+      ANDROID_HOME: ${{ github.workspace }}/.android/sdk
+      ANDROID_SDK_ROOT: ${{ github.workspace }}/.android/sdk
     steps:
       - name: Checkout repo
         uses: actions/checkout@v6
@@ -245,11 +247,11 @@ jobs:
         with:
           path: |
             ${{ env.ANDROID_AVD_HOME }}
-            /usr/local/lib/android/sdk/emulator
-            /usr/local/lib/android/sdk/platform-tools
-            /usr/local/lib/android/sdk/platforms/android-35
-            /usr/local/lib/android/sdk/system-images/android-35/google_apis/x86_64
-          key: ${{ runner.os }}-mobilegl-avd-api35-google_apis-x86_64-pixel_6-v1-${{ hashFiles('android-plugin/run-avd-ci.sh') }}
+            ${{ env.ANDROID_SDK_ROOT }}/emulator
+            ${{ env.ANDROID_SDK_ROOT }}/platform-tools
+            ${{ env.ANDROID_SDK_ROOT }}/platforms/android-35
+            ${{ env.ANDROID_SDK_ROOT }}/system-images/android-35/google_apis/x86_64
+          key: ${{ runner.os }}-mobilegl-avd-api35-google_apis-x86_64-pixel_6-v2-${{ hashFiles('android-plugin/run-avd-ci.sh') }}
 
       - name: Create AVD
         if: steps.android-avd-cache.outputs.cache-hit != 'true'
@@ -274,6 +276,8 @@ jobs:
     env:
       AVD_NAME: mobilegl-ci
       ANDROID_AVD_HOME: ${{ github.workspace }}/.android/avd
+      ANDROID_HOME: ${{ github.workspace }}/.android/sdk
+      ANDROID_SDK_ROOT: ${{ github.workspace }}/.android/sdk
     strategy:
       fail-fast: false
       max-parallel: 4
@@ -288,7 +292,7 @@ jobs:
       - name: Set Swap Space
         uses: pierotofy/set-swap-space@v1.0
         with:
-          swap-size-gb: 16
+          swap-size-gb: 8
 
       - name: Checkout repo
         uses: actions/checkout@v6
@@ -324,11 +328,11 @@ jobs:
         with:
           path: |
             ${{ env.ANDROID_AVD_HOME }}
-            /usr/local/lib/android/sdk/emulator
-            /usr/local/lib/android/sdk/platform-tools
-            /usr/local/lib/android/sdk/platforms/android-35
-            /usr/local/lib/android/sdk/system-images/android-35/google_apis/x86_64
-          key: ${{ runner.os }}-mobilegl-avd-api35-google_apis-x86_64-pixel_6-v1-${{ hashFiles('android-plugin/run-avd-ci.sh') }}
+            ${{ env.ANDROID_SDK_ROOT }}/emulator
+            ${{ env.ANDROID_SDK_ROOT }}/platform-tools
+            ${{ env.ANDROID_SDK_ROOT }}/platforms/android-35
+            ${{ env.ANDROID_SDK_ROOT }}/system-images/android-35/google_apis/x86_64
+          key: ${{ runner.os }}-mobilegl-avd-api35-google_apis-x86_64-pixel_6-v2-${{ hashFiles('android-plugin/run-avd-ci.sh') }}
 
       - name: Download retrace APK
         uses: actions/download-artifact@v8
@@ -378,27 +382,51 @@ jobs:
           if [ "${{ matrix.case.coherent_as_flush || false }}" = "true" ]; then
             extra_retrace_args+=(--coherent-as-flush)
           fi
-          timeout "$(( ${{ matrix.case.timeout_seconds }} + 300 ))" sh android-plugin/trace-replay-ci.sh \
-            --apk-file "${apk_file}" \
-            --package top.mobilegl.plugin.trace \
-            --backend "${{ matrix.backend.name }}" \
-            --result-root android-retrace-result \
-            --fixture-root android-retrace-fixture \
-            --case "${{ matrix.case.name }}" \
-            --trace-archive "${{ matrix.case.trace_archive }}" \
-            --trace-file "${{ matrix.case.trace_file }}" \
-            --golden "${{ matrix.case.golden }}" \
-            --alternate-golden "${{ matrix.case.alternate_golden || '' }}" \
-            --target-call "${{ matrix.case.target_call }}" \
-            --width "${{ matrix.case.width }}" \
-            --height "${{ matrix.case.height }}" \
-            --ssim-threshold "${{ matrix.case.ssim_threshold || '0.99' }}" \
-            --crop-x "${{ matrix.case.crop_x }}" \
-            --crop-y "${{ matrix.case.crop_y }}" \
-            --crop-width "${{ matrix.case.crop_width }}" \
-            --crop-height "${{ matrix.case.crop_height }}" \
-            --timeout-seconds "${{ matrix.case.timeout_seconds }}" \
-            "${extra_retrace_args[@]}"
+
+          run_retrace() {
+            timeout "$(( ${{ matrix.case.timeout_seconds }} + 300 ))" sh android-plugin/trace-replay-ci.sh \
+              --apk-file "${apk_file}" \
+              --package top.mobilegl.plugin.trace \
+              --backend "${{ matrix.backend.name }}" \
+              --result-root android-retrace-result \
+              --fixture-root android-retrace-fixture \
+              --case "${{ matrix.case.name }}" \
+              --trace-archive "${{ matrix.case.trace_archive }}" \
+              --trace-file "${{ matrix.case.trace_file }}" \
+              --golden "${{ matrix.case.golden }}" \
+              --alternate-golden "${{ matrix.case.alternate_golden || '' }}" \
+              --target-call "${{ matrix.case.target_call }}" \
+              --width "${{ matrix.case.width }}" \
+              --height "${{ matrix.case.height }}" \
+              --ssim-threshold "${{ matrix.case.ssim_threshold || '0.99' }}" \
+              --crop-x "${{ matrix.case.crop_x }}" \
+              --crop-y "${{ matrix.case.crop_y }}" \
+              --crop-width "${{ matrix.case.crop_width }}" \
+              --crop-height "${{ matrix.case.crop_height }}" \
+              --timeout-seconds "${{ matrix.case.timeout_seconds }}" \
+              "${extra_retrace_args[@]}"
+          }
+
+          retrace_status=0
+          run_retrace || retrace_status=$?
+          if [ "${retrace_status}" -eq 75 ]; then
+            echo "::warning::Android emulator infrastructure failed; restarting it and retrying this retrace once."
+            sh android-plugin/run-avd-ci.sh stop \
+              --avd-name "${AVD_NAME}" \
+              --emulator-log "${EMULATOR_LOG}" \
+              --pid-file "${EMULATOR_PID_FILE}"
+            adb kill-server || true
+            sleep 2
+            sh android-plugin/run-avd-ci.sh start \
+              --avd-name "${AVD_NAME}" \
+              --gpu "${{ matrix.backend.gpu }}" \
+              --emulator-log "${EMULATOR_LOG}" \
+              --pid-file "${EMULATOR_PID_FILE}" \
+              --boot-timeout 300
+            run_retrace
+          elif [ "${retrace_status}" -ne 0 ]; then
+            exit "${retrace_status}"
+          fi
 
       - name: Collect retrace summary inputs
         if: always()

.github/workflows/test.yml

@@ -107,6 +107,7 @@ jobs:
             --exclude='build.ninja' \
             --exclude='cmake_install.cmake' \
             -czf ci-artifacts/mobilegl-linux-runtime.tgz \
+            "${BUILD_DIR}/CTestTestfile.cmake" \
             "${BUILD_DIR}/MobileGL/MG_Test" \
             "${BUILD_DIR}/MobileGL/MG_Benchmark" \
             "${SHARED_LIBS[@]}"
@@ -156,12 +157,12 @@ jobs:
           PY
 
       - name: Test
-        working-directory: build-linux/MobileGL/MG_Test
+        working-directory: build-linux
         run: |
           if [ "${{ secrets.ACTIONS_STEP_DEBUG }}" = "true" ]; then
-            ctest -V
+            ctest -V -L unit --no-tests=error
           else
-            ctest --output-on-failure
+            ctest --output-on-failure -L unit --no-tests=error
           fi
 
   benchmark:
@@ -202,8 +203,8 @@ jobs:
           PY
 
       - name: Benchmark
-        working-directory: build-linux/MobileGL/MG_Benchmark
-        run: ctest -V -C Release
+        working-directory: build-linux
+        run: ctest -V -C Release -L benchmark --no-tests=error
 
   build-retrace:
     runs-on: ubuntu-latest
@@ -454,6 +455,15 @@ jobs:
           if [ '${{ matrix.backend }}' = 'DirectVulkan' ]; then
             export MOBILEGL_MAGMA_R11G11B10F_FALLBACK=1
           fi
+          # The blended depth-write quirk auto-enables only on Qualcomm, which no CI
+          # runner has, so force it on for the OIT case it exists to fix. ForceOn
+          # bypasses only the vendor gate, so this exercises the real strip on
+          # lavapipe. The Android AVD lane deliberately leaves it off, keeping the
+          # unstripped path covered for the same trace.
+          if [ '${{ matrix.backend }}' = 'DirectVulkan' ] \
+             && [ '${{ matrix.case }}' = 'improved-transparency-minecraft-26.3' ]; then
+            export MOBILEGL_MAGMA_DISABLE_BLENDED_DEPTH_WRITE=1
+          fi
           ctest -V --no-tests=error -R '^MobileGLTraceReplay\.${{ matrix.case }}\.${{ matrix.backend }}$'
 
       - name: Upload actual image

CMakeLists.txt

@@ -188,8 +188,15 @@ set(SOURCE_FILES
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/EliminateFloatEqualsZeroPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/RenameSamplerFunctionParameterPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/DecomposeWorkgroupVec3Pass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/DecoratePositionInvariantPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/LowerDrawParametersPass.cpp
     MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/RebaseInstanceIndexPass.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/FoldConstOffsetFor1DFetchPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/LowerClipDistanceForEsslPass.cpp
+    MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/DefeatConstStructArrayLutPass.cpp
 
     MobileGL/MG_Util/BackendLoaders/OpenGL/Loader.cpp
     MobileGL/MG_Util/BackendLoaders/Vulkan/Loader.cpp
@@ -299,6 +306,13 @@ if (ANDROID)
     )
 endif()
 
+if (WIN32)
+    list(APPEND SOURCE_FILES
+        MobileGL/MG_Impl/WGLImpl/WGLImpl.cpp
+        MobileGL/MG_Impl/WGLImpl/Exporting/Definitions.cpp
+    )
+endif()
+
 set(MOBILEGL_LINK_LIBRARIES
         glslang::glslang
         spirv-cross-c
@@ -327,10 +341,18 @@ set(MOBILEGL_INCLUDE_DIR
         ${SPIRV-Headers_SOURCE_DIR}/include
 )
 
-add_library(${CMAKE_PROJECT_NAME} SHARED 
+add_library(${CMAKE_PROJECT_NAME} SHARED
     ${SOURCE_FILES}
 )
 
+if (WIN32)
+    # The wgl* entry points are exported via .def (see the comment in wgl.def);
+    # only the shared library links it.
+    target_sources(${CMAKE_PROJECT_NAME} PRIVATE
+        MobileGL/MG_Impl/WGLImpl/Exporting/wgl.def
+    )
+endif()
+
 if (CMAKE_BUILD_TYPE STREQUAL "Debug")
     set_target_properties(${CMAKE_PROJECT_NAME} PROPERTIES
         C_VISIBILITY_PRESET default
@@ -373,6 +395,18 @@ if(UNIX AND NOT APPLE AND NOT ANDROID)
     endforeach()
 endif()
 
+if(WIN32)
+    # Drop-in for the classic GL loader path: a copy named opengl32.dll placed
+    # next to a host executable is what LoadLibrary("opengl32.dll") and gdi32's
+    # pixel-format forwarding will resolve.
+    add_custom_command(TARGET ${CMAKE_PROJECT_NAME} POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different
+                "$<TARGET_FILE:${CMAKE_PROJECT_NAME}>"
+                "$<TARGET_FILE_DIR:${CMAKE_PROJECT_NAME}>/opengl32.dll"
+        COMMENT "Creating opengl32.dll drop-in copy"
+    )
+endif()
+
 if(NOT ANDROID)
     add_library(${CMAKE_PROJECT_NAME}_s STATIC 
         ${SOURCE_FILES}
@@ -475,6 +509,15 @@ if (NOT ANDROID AND NOT MOBILEGL_IOS)
 endif ()
 
 if (NOT ANDROID)
+    # Enable testing in the top-level scope so a CTestTestfile.cmake is emitted
+    # at the build-tree root. This lets `ctest` be invoked from the top-level
+    # build directory (IDE "run all tests", CI) and discover every test in the
+    # subdirectories below, instead of having to descend into each
+    # MG_Test/MG_Benchmark subdirectory. Tests are tagged with CTest labels
+    # (unit / benchmark / integration), so e.g. `ctest -L unit` selects just
+    # the unit suite.
+    enable_testing()
+
     if (MOBILEGL_BUILD_TEST)
         add_subdirectory(MobileGL/MG_Test)
     endif()
@@ -484,7 +527,6 @@ if (NOT ANDROID)
     endif()
 
     if (MOBILEGL_BUILD_TRACE_REPLAY)
-        enable_testing()
         add_subdirectory(tools/trace_replay)
     endif()
 endif()

MobileGL/Config.h

@@ -20,6 +20,15 @@ namespace MobileGL::MG_Config {
 
     extern BackendType ActiveBackendType;
 
+    // Tri-state override for device-specific quirks: Auto lets the detected device decide,
+    // ForceOn/ForceOff bypass the detection in either direction. ForceOn only bypasses the
+    // device gate - each quirk keeps its structural safety checks.
+    enum class QuirkOverride : Uint8 {
+        Auto = 0,
+        ForceOn,
+        ForceOff,
+    };
+
     // Feature toggles parsed once from environment variables in MG_ConfigLoader::Init()
     // (ConfigLoader.cpp), before the accepted-env map is destroyed. All Bool fields share
     // one truthy rule: the variable is set, non-empty, not "0", and not "false"
@@ -61,6 +70,32 @@ namespace MobileGL::MG_Config {
         // per-draw glBufferSubData path instead of the persistent-mapped ring allocator
         // (negative control / driver-bug escape hatch).
         Bool DisableUboRing = false;
+        // MOBILEGL_RELAXED_SEMANTICS: relax strict core-profile rules (e.g. VAO-0 draws,
+        // texture-name reuse after delete) even on contexts that explicitly requested a core
+        // profile. Without it, relaxed semantics still apply to every context that did not
+        // 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_QUIRK_CLIP_DISTANCE: overrides the DirectGLES quirk that lowers
+        // gl_ClipDistance for Adreno's ESSL compiler (shadow Private arrays with
+        // constant-index builtin flushes, dynamic-index gl_in copy loop, redeclaration
+        // strip, and const struct-array LUT splitting). Auto detects Qualcomm.
+        QuirkOverride ClipDistanceQuirk = 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
+        // cross-pipeline vertex position invariance. Sorted-transparency "over" blends,
+        // gl_FragDepth writers, and fully color-masked attachments are exempt (see
+        // PipelineFactory::ShouldSuppressDepthWrite). Auto detects Qualcomm.
+        QuirkOverride MagmaDisableBlendedDepthWriteQuirk = QuirkOverride::Auto;
+        // MOBILEGL_DISABLE_ROBUST_BUFFER_ACCESS: leave the Vulkan robustBufferAccess device
+        // feature off. It is enabled by default to match GL's defined out-of-range fetch
+        // behavior; this escape hatch exists to measure or dodge its GPU cost on a device.
+        Bool DisableRobustBufferAccess = false;
     };
     extern FeaturesTable Features;
 } // namespace MobileGL::MG_Config

MobileGL/ConfigLoader.cpp

@@ -86,6 +86,17 @@ namespace MobileGL::MG_ConfigLoader {
         return it != acceptedEnvVariablesMap->end() && IsTruthyValue(it->second);
     }
 
+    // Quirk overrides are tri-state: an unset variable keeps device auto-detection, a truthy
+    // value forces the quirk on, anything else set ("0", "false", "") forces it off.
+    inline MG_Config::QuirkOverride QueryEnvQuirkOverride(const String& key) {
+        auto it = acceptedEnvVariablesMap->find(key);
+        if (it == acceptedEnvVariablesMap->end()) {
+            return MG_Config::QuirkOverride::Auto;
+        }
+        return IsTruthyValue(it->second) ? MG_Config::QuirkOverride::ForceOn
+                                         : MG_Config::QuirkOverride::ForceOff;
+    }
+
     inline Uint32 QueryEnvUint32(const String& key, Uint32 defaultValue, Uint32 minValue, Uint32 maxValue) {
         auto it = acceptedEnvVariablesMap->find(key);
         if (it == acceptedEnvVariablesMap->end()) {
@@ -122,6 +133,12 @@ namespace MobileGL::MG_ConfigLoader {
         features.CoherentAsFlush = QueryEnvFlag("MOBILEGL_COHERENT_AS_FLUSH");
         features.TraceSkipAutodestroy = QueryEnvFlag("MOBILEGL_TRACE_SKIP_AUTODESTROY");
         features.DisableUboRing = QueryEnvFlag("MOBILEGL_DISABLE_UBO_RING");
+        features.RelaxedSemantics = QueryEnvFlag("MOBILEGL_RELAXED_SEMANTICS");
+        features.SubgroupPrefixScanQuirk = QueryEnvQuirkOverride("MOBILEGL_QUIRK_SUBGROUP_PREFIX_SCAN");
+        features.ClipDistanceQuirk = QueryEnvQuirkOverride("MOBILEGL_QUIRK_CLIP_DISTANCE");
+        features.MagmaDisableBlendedDepthWriteQuirk =
+            QueryEnvQuirkOverride("MOBILEGL_MAGMA_DISABLE_BLENDED_DEPTH_WRITE");
+        features.DisableRobustBufferAccess = QueryEnvFlag("MOBILEGL_DISABLE_ROBUST_BUFFER_ACCESS");
     }
 
     inline void InitBackendType() {

MobileGL/Defines.h

@@ -34,6 +34,7 @@
 #define MOBILEGL_EGL_API MOBILEGL_API
 #define MOBILEGL_CGL_API MOBILEGL_API
 #define MOBILEGL_NSOPENGL_API MOBILEGL_API
+#define MOBILEGL_WGL_API MOBILEGL_API
 
 // ====================== MobileGL configurations ======================= //
 #ifndef MOBILEGL_LOG_ACTIVE_LEVEL

MobileGL/GlobalObjects.cpp

@@ -14,7 +14,13 @@ namespace MobileGL {
     } // namespace MG_Config
 
     namespace MG_Backend {
-        UniquePtr<BackendObject> pActiveBackendObject;
+        // Leak-at-exit storage: the UniquePtr itself lives on the heap and is
+        // never destroyed by the runtime, so process exit runs no backend
+        // destructors (static destruction order across TUs is undefined).
+        // Deterministic teardown happens inside the EGL lifecycle instead:
+        // the last eglTerminate calls MobileGL::Destroy(), which .reset()s
+        // these singletons while the process is still healthy.
+        UniquePtr<BackendObject>& pActiveBackendObject = *new UniquePtr<BackendObject>();
         GlobalBackendFunctionsTable gBackendFunctionsTable;
     } // namespace MG_Backend
 } // namespace MobileGL

MobileGL/Init.cpp

@@ -9,14 +9,24 @@
 #include "Init.h"
 #include "Config.h"
 #include <MG_Backend/BackendObjects.h>
+#include <MG_Backend/DirectVulkan/DirectVulkan.h>
 #include <MG_State/GLState/Core.h>
 #include <MG_State/EGLState/Core.h>
 #include <MG_Impl/GLImpl/Texture/ProxyTexture.h>
 #include <MG_Impl/GLImpl/Framebuffer/GL_Framebuffer.h>
 
+#include <atomic>
+#include <mutex>
+
 namespace MobileGL {
     namespace {
-        Bool g_isInitialized = false;
+        std::atomic<Bool> g_isInitialized = false;
+        thread_local Bool tl_initializing = false;
+
+        std::mutex& InitMutex() {
+            static std::mutex mutex;
+            return mutex;
+        }
 
         void DestroyImpl(Bool logLifecycle) {
             if (!g_isInitialized) {
@@ -64,40 +74,35 @@ namespace MobileGL {
         MGLOG_I("MobileGL initialized");
     }
 
+    void EnsureInitialized() {
+        if (g_isInitialized.load(std::memory_order_acquire)) {
+            return;
+        }
+        // Re-entrant call while this thread is already inside Initialize()
+        // (e.g. an init step routing back through a public entry point).
+        if (tl_initializing) {
+            return;
+        }
+        const std::lock_guard<std::mutex> lock(InitMutex());
+        if (g_isInitialized.load(std::memory_order_acquire)) {
+            return;
+        }
+        tl_initializing = true;
+        Initialize();
+        tl_initializing = false;
+    }
+
     void Destroy() {
         DestroyImpl(true);
     }
 
-#if defined(__linux__) || defined(__APPLE__)
-    __attribute__((constructor)) static void AutoInit() {
-        Initialize();
-    }
-
-    __attribute__((destructor)) static void AutoDestroy() {
-        if (MG_Config::Features.TraceSkipAutodestroy) {
-            return;
-        }
-#if defined(__APPLE__)
-        // macOS injected dylibs can run destructors after logging/backend static state is already torn down.
-        return;
-#else
-        DestroyImpl(false);
-#endif
-    }
-#endif
-
-#ifdef _WIN32
-    BOOL WINAPI DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved) {
-        switch (ul_reason_for_call) {
-        case DLL_PROCESS_ATTACH:
-            Initialize();
-            break;
-
-        case DLL_PROCESS_DETACH:
-            Destroy();
-            break;
-        }
-        return TRUE;
-    }
-#endif
+    // MobileGL's lifecycle is owned entirely by the host-API layers
+    // (EGL/WGL/CGL): initialization happens lazily on the first entry point
+    // via EnsureInitialized(), and full teardown happens deterministically
+    // when the last EGL display is terminated with nothing current (EGLImpl
+    // calls Destroy()). There is intentionally no static constructor, no
+    // static destructor, and no DllMain: the global singletons use
+    // leak-at-exit storage (see GlobalObjects.cpp), so a process that exits
+    // without eglTerminate simply leaks them to the OS instead of running
+    // backend destructors during static teardown.
 } // namespace MobileGL

MobileGL/Init.h

@@ -11,6 +11,12 @@
 
 namespace MobileGL {
     void Initialize();
+    // Thread-safe, idempotent, and re-entrant wrapper around Initialize().
+    // Host layers (EGL/WGL/CGL entry points) call this lazily on first use so
+    // MobileGL's lifecycle never depends on ELF/DLL static constructors, and
+    // so a fresh init can follow a full Destroy() (e.g. after the last
+    // eglTerminate).
+    void EnsureInitialized();
     void Destroy();
 
     namespace MG_Util::Debug {

MobileGL/MG_Backend/BackendObject.h

@@ -230,8 +230,26 @@ namespace MobileGL {
             void (*SetSwapInterval)(Int interval);
         };
 
+        // Coarse GPU vendor identity for gating device-specific quirks. Detected from the
+        // Vulkan physical-device vendorID or the GLES GL_VENDOR/GL_RENDERER strings; stays
+        // Unknown when detection is inconclusive, in which case auto-gated quirks stay off.
+        enum class GpuVendorKind : Uint8 {
+            Unknown = 0,
+            Qualcomm,
+            Arm,
+            Nvidia,
+            Amd,
+            Intel,
+            ImgTec,
+            // Software rasterizers (llvmpipe/lavapipe, SwiftShader).
+            Software,
+        };
+
         struct DynamicBackendParameters {
             SizeT UniformBufferOffsetAlignment = 256;
+            // GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT. 1.0 means the backend cannot filter anisotropically,
+            // which is also why the extension is not advertised in that case.
+            Float MaxTextureMaxAnisotropy = 1.0f;
             Float AliasedLineWidthRangeMin = 1.0f;
             Float AliasedLineWidthRangeMax = 1.0f;
             Float SmoothLineWidthRangeMin = 1.0f;
@@ -269,6 +287,9 @@ namespace MobileGL {
             Int MaxUniformBlockSize = 16384;
             Int MaxImageUnits = 8;
             Int MaxCombinedImageUniforms = 8;
+            Int MaxVertexImageUniforms = 0;
+            Int MaxGeometryImageUniforms = 0;
+            Int MaxFragmentImageUniforms = 8;
             Int MaxComputeImageUniforms = 8;
             Int MaxDrawBuffers = 8;
             Int MaxColorAttachments = 8;
@@ -285,13 +306,15 @@ namespace MobileGL {
             Uint32 SubgroupSupportedStages = 0;
             Uint32 SubgroupSupportedFeatures = 0;
             Bool SubgroupQuadOperationsInAllStages = false;
+            GpuVendorKind GpuVendor = GpuVendorKind::Unknown;
         };
 
         enum class WindowBackend {
             Android,
             X11,
             MetalLayer,
-            // TODO: Wayland, Windows, etc.
+            Win32, // Handle is an HWND
+            // TODO: Wayland, etc.
             WindowBackendCount,
             Unknown = -1
         };

MobileGL/MG_Backend/BackendObjects.h

@@ -13,6 +13,6 @@
 #include "DirectVulkan/BackendObject_DirectVulkan.h"
 
 namespace MobileGL::MG_Backend {
-    extern UniquePtr<BackendObject> pActiveBackendObject;
+    extern UniquePtr<BackendObject>& pActiveBackendObject;
     extern GlobalBackendFunctionsTable gBackendFunctionsTable;
 } // namespace MobileGL::MG_Backend

MobileGL/MG_Backend/DirectGLES/BackendObject_DirectGLES.cpp

@@ -605,9 +605,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
                     {
                         .TargetGLVersion = {3, 3, 0},   // Target OpenGL Version
                         .TargetGLSLVersion = {4, 6, 0}, // Target Shading Language Version
-                        // Baseline advertisement (no timer queries yet); reconciled once
-                        // the ES capabilities exist, see UpdateAdvertisedTimerQueryExtension.
-                        .Extensions = BuildAdvertisedExtensions(false),
+                        // Baseline advertisement (no timer queries / anisotropy yet); reconciled
+                        // once the ES capabilities exist, see UpdateAdvertisedCapabilityExtensions.
+                        .Extensions = BuildAdvertisedExtensions(false, false),
                         .IsCompatibilityProfile = false // Is Compatibility Profile
                     },
                 .StaticBackendCapability = {.AllowVSOnlyPrograms = false} // Backend Capability
@@ -627,8 +627,9 @@ 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 UpdateAdvertisedTimerQueryExtension() {
-            MutableRendererInfo().RendererGLInfo.Extensions = BuildAdvertisedExtensions(AreTimerQueriesSupported());
+        void UpdateAdvertisedCapabilityExtensions(Bool anisotropicFilteringSupported) {
+            MutableRendererInfo().RendererGLInfo.Extensions =
+                BuildAdvertisedExtensions(AreTimerQueriesSupported(), anisotropicFilteringSupported);
         }
     } // namespace
 
@@ -672,11 +673,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
             return false;
         }
         DirectGLES::SetGLESCapabilities(m_GLESCapabilities);
-        // Now that g_GLESCapabilities knows about GL_EXT_disjoint_timer_query,
-        // reconcile the E_GL_ARB_timer_query advertisement (see the comment on
-        // UpdateAdvertisedTimerQueryExtension for why it cannot happen when
-        // the extension list is first built).
-        UpdateAdvertisedTimerQueryExtension();
+        // 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);
         UpdateDynamicBackendParameters();
         PopulateFormatCapabilities(m_GLESFunctions, m_GLESCapabilities, MutableFormatCapabilities());
         PrintFormatCapabilities(GetFormatCapabilities());
@@ -700,9 +701,10 @@ namespace MobileGL::MG_Backend::DirectGLES {
 
         if ((handle.Backend != WindowBackend::Android &&
              handle.Backend != WindowBackend::X11 &&
-             handle.Backend != WindowBackend::MetalLayer) ||
+             handle.Backend != WindowBackend::MetalLayer &&
+             handle.Backend != WindowBackend::Win32) ||
             !handle.Handle) {
-            MGLOG_E("DirectGLES backend only supports Android, X11, and CAMetalLayer native windows");
+            MGLOG_E("DirectGLES backend only supports Android, X11, CAMetalLayer, and Win32 native windows");
             return false;
         }
 
@@ -818,14 +820,14 @@ namespace MobileGL::MG_Backend::DirectGLES {
         return MutableRendererInfo();
     }
 
-    Vector<GLExtension> BuildAdvertisedExtensions(Bool timerQueriesSupported) {
+    Vector<GLExtension> BuildAdvertisedExtensions(Bool timerQueriesSupported, Bool anisotropicFilteringSupported) {
         Vector<GLExtension> extensions = {V_OpenGL30, V_OpenGL31, V_OpenGL32,
                                           V_OpenGL33, 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_depth_texture, E_GL_ARB_buffer_storage,
                                           E_GL_ARB_texture_storage, E_GL_ARB_texture_storage_multisample,
-                                          E_GL_ARB_direct_state_access,
+                                          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, E_GL_ARB_gpu_shader5, E_GL_ARB_multi_bind,
                                           E_GL_ARB_shading_language_420pack, E_GL_ARB_vertex_attrib_binding,
@@ -836,6 +838,14 @@ namespace MobileGL::MG_Backend::DirectGLES {
         if (timerQueriesSupported && !MG_Config::Features.DisableTimerQuery) {
             extensions.push_back(E_GL_ARB_timer_query);
         }
+        // Only advertised when the host ES driver actually filters anisotropically: the sampler
+        // state is accepted regardless, but forwarding it would be a no-op without the extension,
+        // and an app that trusts the string (LWJGL builds GLCapabilities from it) would silently
+        // get plain trilinear.
+        if (anisotropicFilteringSupported) {
+            extensions.push_back(E_GL_EXT_texture_filter_anisotropic);
+            extensions.push_back(E_GL_ARB_texture_filter_anisotropic);
+        }
         return extensions;
     }
 
@@ -938,8 +948,15 @@ namespace MobileGL::MG_Backend::DirectGLES {
         return m_dynamicParameters;
     }
 
+    void BackendObject_DirectGLES::ApplyGLESCapabilitiesForTesting(
+        const MG_External::GLESCapabilities& capabilities) {
+        m_GLESCapabilities = capabilities;
+        UpdateDynamicBackendParameters();
+    }
+
     void BackendObject_DirectGLES::UpdateDynamicBackendParameters() {
         m_dynamicParameters.UniformBufferOffsetAlignment = m_GLESCapabilities.UniformBufferOffsetAlignment;
+        m_dynamicParameters.MaxTextureMaxAnisotropy = m_GLESCapabilities.MaxTextureMaxAnisotropy;
         m_dynamicParameters.AliasedLineWidthRangeMin = m_GLESCapabilities.AliasedLineWidthRangeMin;
         m_dynamicParameters.AliasedLineWidthRangeMax = m_GLESCapabilities.AliasedLineWidthRangeMax;
         m_dynamicParameters.SmoothLineWidthRangeMin = m_GLESCapabilities.SmoothLineWidthRangeMin;
@@ -993,9 +1010,21 @@ namespace MobileGL::MG_Backend::DirectGLES {
         m_dynamicParameters.MaxUniformBlockSize = m_GLESCapabilities.MaxUniformBlockSize;
         const Int maxSupportedTextureUnits =
             static_cast<Int>(MG_State::GLState::TextureState::MAX_TEXTURE_IMAGE_UNITS);
-        m_dynamicParameters.MaxImageUnits = std::min(m_GLESCapabilities.MaxImageUnits, maxSupportedTextureUnits);
-        m_dynamicParameters.MaxCombinedImageUniforms = m_GLESCapabilities.MaxCombinedImageUniforms;
-        m_dynamicParameters.MaxComputeImageUniforms = m_GLESCapabilities.MaxComputeImageUniforms;
+        m_dynamicParameters.MaxImageUnits =
+            std::max(std::min(m_GLESCapabilities.MaxImageUnits, maxSupportedTextureUnits), 0);
+        m_dynamicParameters.MaxCombinedImageUniforms = std::max(m_GLESCapabilities.MaxCombinedImageUniforms, 0);
+        const auto clampStageImageUniforms = [this](Int stageLimit) {
+            return std::min({std::max(stageLimit, 0), m_dynamicParameters.MaxImageUnits,
+                             m_dynamicParameters.MaxCombinedImageUniforms});
+        };
+        m_dynamicParameters.MaxVertexImageUniforms =
+            clampStageImageUniforms(m_GLESCapabilities.MaxVertexImageUniforms);
+        m_dynamicParameters.MaxGeometryImageUniforms =
+            clampStageImageUniforms(m_GLESCapabilities.MaxGeometryImageUniforms);
+        m_dynamicParameters.MaxFragmentImageUniforms =
+            clampStageImageUniforms(m_GLESCapabilities.MaxFragmentImageUniforms);
+        m_dynamicParameters.MaxComputeImageUniforms =
+            clampStageImageUniforms(m_GLESCapabilities.MaxComputeImageUniforms);
         m_dynamicParameters.MaxDrawBuffers = m_GLESCapabilities.MaxDrawBuffers;
         m_dynamicParameters.MaxColorAttachments = m_GLESCapabilities.MaxColorAttachments;
         m_dynamicParameters.MaxClipDistances = m_GLESCapabilities.MaxClipDistances;
@@ -1007,6 +1036,32 @@ namespace MobileGL::MG_Backend::DirectGLES {
         m_dynamicParameters.ViewportSubpixelBits = m_GLESCapabilities.ViewportSubpixelBits;
         m_dynamicParameters.SupportsWideLines =
             m_GLESCapabilities.AliasedLineWidthRangeMax > 1.0f || m_GLESCapabilities.SmoothLineWidthRangeMax > 1.0f;
+
+        const auto containsAny = [](const String& haystack, std::initializer_list<const char*> needles) {
+            return std::any_of(needles.begin(), needles.end(), [&](const char* needle) {
+                return haystack.find(needle) != String::npos;
+            });
+        };
+        const String vendorAndRenderer =
+            m_GLESCapabilities.GLESVendorString + " " + m_GLESCapabilities.GLESRendererString;
+        if (containsAny(vendorAndRenderer, {"llvmpipe", "SwiftShader", "softpipe"})) {
+            // Check software rasterizers first: ANGLE-on-llvmpipe reports both.
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Software;
+        } else if (containsAny(vendorAndRenderer, {"Qualcomm", "Adreno"})) {
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Qualcomm;
+        } else if (containsAny(vendorAndRenderer, {"Mali", "ARM"})) {
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Arm;
+        } else if (containsAny(vendorAndRenderer, {"NVIDIA"})) {
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Nvidia;
+        } else if (containsAny(vendorAndRenderer, {"AMD", "Radeon"})) {
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Amd;
+        } else if (containsAny(vendorAndRenderer, {"Intel"})) {
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Intel;
+        } else if (containsAny(vendorAndRenderer, {"Imagination", "PowerVR"})) {
+            m_dynamicParameters.GpuVendor = GpuVendorKind::ImgTec;
+        } else {
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Unknown;
+        }
     }
 
     const MG_External::GLESFunctionsTable& BackendObject_DirectGLES::GetGLESFunctions() const {

MobileGL/MG_Backend/DirectGLES/BackendObject_DirectGLES.h

@@ -41,6 +41,7 @@ namespace MobileGL::MG_Backend::DirectGLES {
 
         const MG_External::GLESFunctionsTable& GetGLESFunctions() const;
         const MG_External::EGLFunctionsTable& GetEGLFunctions() const;
+        void ApplyGLESCapabilitiesForTesting(const MG_External::GLESCapabilities& capabilities);
 
     private:
         void UpdateDynamicBackendParameters();
@@ -66,9 +67,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
     const RendererInfo& GetRendererIdentity();
 
     // The full OpenGL extension list Espryt advertises (glGetString(GL_EXTENSIONS))
-    // for a device whose timer queries are (or are not) usable. The
-    // MOBILEGL_DISABLE_TIMERQUERY escape hatch is applied inside.
-    Vector<GLExtension> BuildAdvertisedExtensions(Bool timerQueriesSupported);
+    // for a device whose timer queries / anisotropic filtering are (or are not) usable.
+    // The MOBILEGL_DISABLE_TIMERQUERY escape hatch is applied inside.
+    Vector<GLExtension> BuildAdvertisedExtensions(Bool timerQueriesSupported, Bool anisotropicFilteringSupported);
 
     // 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

@@ -19,6 +19,10 @@
     operation Utils::CheckGLESError();
 
 namespace MobileGL::MG_Backend::DirectGLES {
+    // Re-establishes the frontend texture-unit bindings on the native ES context.
+    // Content uploads use scratch bindings, so draws and dispatches call this after
+    // texture synchronization.
+    void BindCurrentTextures();
     void ClearBufferfi(GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil);
     void ClearBufferfv(GLenum buffer, GLint drawbuffer, const GLfloat* value);
     void ClearBufferuiv(GLenum buffer, GLint drawbuffer, const GLuint* value);

MobileGL/MG_Backend/DirectGLES/Managers.h

@@ -15,6 +15,7 @@
 #include "MG_State/GLState/TextureState/TextureEnum.h"
 #include <MG_State/GLState/TextureState/TextureObject.h>
 #include <MG_State/GLState/Core.h>
+#include <MG_Util/Converters/MGToGL/TextureEnumConverter.h>
 
 namespace MobileGL::MG_Backend::DirectGLES {
     String EmulateBaseInstanceInVertexShader(String source, GLenum shaderType);
@@ -177,6 +178,21 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // glBindBuffer with a redundant-bind cache for GL_ARRAY_BUFFER.
         void BindBufferId(GLenum target, Uint id);
         void InvalidateArrayBufferBindingCache();
+        // Redundant-bind caches for the driver-level GL_PIXEL_PACK/UNPACK_BUFFER
+        // bindings. Every backend readback (glReadPixels / pack-PBO map) and pixel
+        // upload site routes its binding through these so the shadow always matches
+        // the driver; the resting state between operations is 0, which keeps any
+        // path that implicitly assumes "no PBO bound" correct. Scrubbed when a
+        // buffer id is deleted/pooled (GL resets a deleted buffer's bindings to 0,
+        // and a recycled name matching the shadow would false-skip the rebind) and
+        // invalidated on MakeCurrent (context may reset).
+        void BindPixelPackBufferId(Uint id);
+        void BindPixelUnpackBufferId(Uint id);
+        void InvalidatePixelBufferBindingCaches();
+        // A GL buffer id is being deleted by code outside BufferImpl (e.g. the VAO
+        // client-attribute staging buffers): scrub every buffer-binding shadow that
+        // could false-skip when the name is recycled.
+        void NoteBufferIdDeleted(Uint id);
         // 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/
@@ -242,6 +258,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
         private:
             Uint m_backendVAOId = 0;
             Array<Uint, MG_State::GLState::VertexArrayObject::MAX_VERTEX_ATTRIBS> m_clientAttributeBufferIds;
+            // Attribs the frontend has Enabled but that have no source at all (no buffer object
+            // and NULL client pointer). GL keeps such attribs latently enabled, but Adreno's ES
+            // driver treats them as client arrays and memcpys from address 0 at draw time
+            // (SIGSEGV), so they are kept disabled on the backend VAO until they gain a source.
+            Uint32 m_forceDisabledAttribsMask = 0;
             Bool m_isInitialized = false;
             Uint16 m_syncedIndexBufferVersion = 0;
             Array<MG_State::GLState::VertexAttributeVersion, MG_State::GLState::VertexArrayObject::MAX_VERTEX_ATTRIBS>
@@ -254,10 +275,48 @@ namespace MobileGL::MG_Backend::DirectGLES {
 
     namespace TextureImpl {
         inline Bool IsSupportedTextureTarget(TextureTarget target) {
-            if (target == TextureTarget::Texture1D || target == TextureTarget::TextureRectangle ||
-                target == TextureTarget::Texture1DArray || target == TextureTarget::Texture2DArray)
-                return false;
-            return true;
+            // Rectangle textures need non-normalized sampling ES cannot express; everything else is
+            // either native or emulated (1D -> 2D with height 1, 1D array -> 2D array, see
+            // MapToBackendTextureTarget). SPIRV-Cross already emits the matching ESSL samplers and
+            // coordinate padding for 1D/1D-array shaders.
+            return target != TextureTarget::TextureRectangle;
+        }
+
+        // ES has no 1D targets: 1D textures are stored as 2D (height 1) and 1D arrays as 2D arrays
+        // (height 1, layers in depth). Must match SPIRV-Cross's ES 1D-as-2D shader emulation.
+        inline TextureTarget MapToBackendTextureTarget(TextureTarget target) {
+            switch (target) {
+            case TextureTarget::Texture1D:
+                return TextureTarget::Texture2D;
+            case TextureTarget::Texture1DArray:
+                return TextureTarget::Texture2DArray;
+            default:
+                return target;
+            }
+        }
+
+        inline GLenum ConvertTextureTargetToBackendGLEnum(TextureTarget target) {
+            return MG_Util::ConvertTextureTargetToGLEnum(MapToBackendTextureTarget(target));
+        }
+
+        inline GLenum ConvertTextureUploadTargetToBackendGLEnum(TextureUploadTarget uploadTarget) {
+            switch (uploadTarget) {
+            case TextureUploadTarget::Texture1D:
+                return GL_TEXTURE_2D;
+            case TextureUploadTarget::Texture1DArray:
+                return GL_TEXTURE_2D_ARRAY;
+            default:
+                return MG_Util::ConvertTextureUploadTargetToGLEnum(uploadTarget);
+            }
+        }
+
+        // 1D arrays store layers in the state-side height; the ES 2D-array image keeps height 1 and
+        // moves the layer count into depth.
+        inline IntVec3 GetBackendUploadSize(TextureTarget stateTarget, const IntVec3& texelSize) {
+            if (stateTarget == TextureTarget::Texture1DArray) {
+                return {texelSize.x(), 1, texelSize.y()};
+            }
+            return texelSize;
         }
 
         inline Bool IsMultisampleTextureTarget(TextureTarget target) {
@@ -293,6 +352,12 @@ namespace MobileGL::MG_Backend::DirectGLES {
         class BackendTextureObject {
         public:
             BackendTextureObject();
+            // Deletes the GL texture (frontend glDeleteTextures used to leak every
+            // backend id for the context lifetime) and scrubs the binding/scratch-FBO
+            // shadows so a recycled name or heap address cannot false-skip a rebind.
+            ~BackendTextureObject();
+            BackendTextureObject(const BackendTextureObject&) = delete;
+            BackendTextureObject& operator=(const BackendTextureObject&) = delete;
             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);
@@ -304,6 +369,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
             void RecreateBackendTexture();
 
             Uint m_backendTextureId = 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;
             Bool m_isInitialized = false;
             Bool m_imageBindableStorageRequired = false;
             Bool m_backendStorageImmutable = false;
@@ -328,6 +396,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
                      MG_State::GLState::TextureState::MAX_TEXTURE_IMAGE_UNITS>
             g_boundTexturesCache;
         extern Uint g_activeTextureUnit;
+        // Bumped when the backend ES context is destroyed; texture ids stamped with
+        // an older generation belong to a dead context and must not be deleted.
+        extern Uint g_textureContextGeneration;
     } // namespace TextureImpl
 
     namespace FramebufferImpl {
@@ -336,6 +407,10 @@ namespace MobileGL::MG_Backend::DirectGLES {
             BackendFramebufferObject();
             void SyncToBackend(const SharedPtr<MG_State::GLState::FramebufferObject>& stateFBOObject,
                                FramebufferTarget asTarget);
+            // Apply only this FBO's read buffer (glReadBuffer) to the backend. Split out so it can
+            // still run when SyncCurrentFBO skips the READ-target sync because the same GL FBO is
+            // bound as both draw and read (otherwise glReadBuffer changes would be silently dropped).
+            void SyncReadBufferToBackend(const SharedPtr<MG_State::GLState::FramebufferObject>& stateFBOObject);
             void InvalidateSyncedState();
             Uint GetBackendFramebufferId() const { return m_backendFBOId; }
             void Bind(FramebufferTarget target) const;
@@ -369,8 +444,105 @@ namespace MobileGL::MG_Backend::DirectGLES {
         extern StateBackendObjectRegistry<MG_State::GLState::FramebufferObject, BackendFramebufferObject>
             g_backendFramebufferObjects;
         extern Array<Uint16, SizeT(FramebufferTarget::FramebufferTargetCount)> g_fboBindVersions;
+        // Tracks the bound FBO's object version (bumped on any attachment/drawbuffer change)
+        // per target: re-attaching textures or changing draw buffers on an already-bound FBO
+        // must re-sync it even when the binding-slot version has not moved.
+        extern Array<Uint16, SizeT(FramebufferTarget::FramebufferTargetCount)> g_fboSyncedObjectVersions;
+        extern Array<MG_State::GLState::FramebufferObject*, SizeT(FramebufferTarget::FramebufferTargetCount)>
+            g_fboSyncedObjects;
+
+        // 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
+        // query forces a driver pipeline sync) and so redundant rebinds no-op.
+        // Starts unknown; the first CurrentFramebufferBinding() query pins it from
+        // the driver once. Invalidated on MakeCurrent (context may reset).
+        // GL_FRAMEBUFFER binds both targets.
+        void BindFramebufferId(GLenum fbTarget, Uint id);
+        Uint CurrentFramebufferBinding(FramebufferTarget target);
+        void InvalidateFramebufferBindingCache();
     } // namespace FramebufferImpl
 
+    // Shared scratch framebuffers for the readback/copy/blit emulation paths, with a
+    // driver-side attachment shadow: repeated uses skip redundant detach/attach GL
+    // calls, and an attachment left by one use (e.g. a depth copy's DEPTH_STENCIL
+    // texture) is detached exactly when a later use of another aspect would
+    // otherwise inherit it (stale cross-aspect attachments made the shared temp FBO
+    // incomplete and silently degraded later readbacks).
+    namespace ScratchFBOImpl {
+        struct ScratchFramebuffer {
+            Uint id = 0;
+            // false => attachment state unknown; scrub every point on next use.
+            // A fresh FBO starts with nothing attached, so creation sets it true.
+            Bool attachmentsKnown = false;
+            Uint colorTex = 0;
+            GLenum colorTarget = 0;
+            GLint colorLevel = 0;
+            GLint colorLayer = -1; // >= 0 => attached via glFramebufferTextureLayer
+            Uint depthTex = 0;
+            GLenum depthTarget = 0;
+            GLint depthLevel = 0;
+            Bool depthHasStencil = false;
+            // Per-FBO read/draw buffer state (0 = unknown, set on first use).
+            GLenum readBuffer = 0;
+            GLenum drawBuffer = 0;
+        };
+        ScratchFramebuffer& TempFramebuffer();     // GetTexImage READ / CopyTex*Image2D depth DRAW
+        ScratchFramebuffer& BlitReadFramebuffer(); // texture-to-texture blit source
+        ScratchFramebuffer& BlitDrawFramebuffer(); // texture-to-texture blit destination
+        // Returns the GL id, generating it if needed (requires a current ES context).
+        Uint EnsureId(ScratchFramebuffer& fb);
+        // The fb must currently be bound at fbTarget (glReadBuffer/glDrawBuffers
+        // target the READ/DRAW binding respectively). Each Ensure* performs the
+        // minimal detach/attach set and keeps the shadow in sync; a failed attach
+        // records the point as detached so the completeness check fails instead of
+        // silently reading a stale attachment.
+        void EnsureColorAttachment2D(ScratchFramebuffer& fb, GLenum fbTarget, Uint tex, GLenum texTarget, GLint level);
+        void EnsureColorAttachmentLayer(ScratchFramebuffer& fb, GLenum fbTarget, Uint tex, GLint level, GLint layer);
+        void EnsureDepthAttachment2D(ScratchFramebuffer& fb, GLenum fbTarget, Uint tex, GLenum texTarget, GLint level,
+                                     Bool withStencil);
+        void EnsureNoColorAttachment(ScratchFramebuffer& fb, GLenum fbTarget);
+        void EnsureNoDepthAttachment(ScratchFramebuffer& fb, GLenum fbTarget);
+        void EnsureReadBuffer(ScratchFramebuffer& fb, GLenum readBuffer);
+        void EnsureDrawBuffer(ScratchFramebuffer& fb, GLenum drawBuffer);
+        // A 1x1 RGBA8-renderbuffer-complete FBO (GenerateMipmap needs a complete
+        // binding while respecifying texture storage). Attachment is set once at
+        // creation and never changes.
+        Uint EnsureCompleteTinyFramebufferId();
+        // A backend texture id is being deleted or respecified: a scratch FBO still
+        // referencing it would hold a dangling attachment (ES only auto-detaches
+        // from the *bound* framebuffer), and a recycled name could false-skip a
+        // re-attach; force a full scrub on next use.
+        void NoteTextureIdDeleted(Uint textureId);
+        // The ES context (and the scratch FBO ids with it) is going away.
+        void OnBackendContextDestroyed();
+    } // namespace ScratchFBOImpl
+
+    // Driver-level GL_PACK_* pixel-store shadow, the readback-side sibling of the
+    // upload path's ScopedDefaultUnpackState (Managers.cpp): the backend PACK state
+    // is written ONLY through ApplyPackState, so scoped helpers can save/restore it
+    // from the shadow instead of glGetIntegerv (which forces a driver pipeline
+    // sync), and redundant glPixelStorei calls no-op. The first Apply/Current call
+    // pins the driver to the shadow by writing all fields once. Invalidated on
+    // MakeCurrent (context may reset). PACK_IMAGE_HEIGHT/SKIP_IMAGES/SWAP_BYTES/
+    // LSB_FIRST have no ES equivalents; readbacks honor them on the CPU from the
+    // frontend context state instead.
+    namespace PixelStoreImpl {
+        struct PackState {
+            GLint Alignment = 4;
+            GLint RowLength = 0;
+            GLint SkipRows = 0;
+            GLint SkipPixels = 0;
+            Bool operator==(const PackState& o) const {
+                return Alignment == o.Alignment && RowLength == o.RowLength && SkipRows == o.SkipRows &&
+                       SkipPixels == o.SkipPixels;
+            }
+        };
+        void ApplyPackState(const PackState& desired);
+        PackState CurrentPackState();
+        void InvalidatePackStateCache();
+    } // namespace PixelStoreImpl
+
     // 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.

MobileGL/MG_Backend/DirectGLES/Utils.cpp

@@ -18,6 +18,10 @@
 #include <MG_Util/Converters/GLToStr/GLEnumConverter.h>
 #include <MG_Util/Converters/MGToGL/TextureEnumConverter.h>
 #include <MG_Util/Converters/MGToGL/FramebufferEnumConverter.h>
+#include <MG_Util/Math/HalfFloat.h>
+#include <MG_Util/Math/SmallFloat.h>
+
+#include <cmath>
 
 namespace MobileGL::MG_Backend::DirectGLES {
     namespace {
@@ -338,6 +342,41 @@ namespace MobileGL::MG_Backend::DirectGLES {
             }
             return result;
         }
+
+        String RemoveClipDistanceRedeclaration(const String& glslCode) {
+#ifdef TRACY_ENABLE
+            ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
+#endif
+            // Adreno rejects any redeclaration of gl_ClipDistance/gl_CullDistance ("reserved
+            // built-in name") even with GL_EXT_clip_cull_distance required, but accepts plain
+            // usage of the builtin. Drop the desktop-style redeclaration line SPIRV-Cross
+            // prints; the "#extension GL_EXT_clip_cull_distance : require" line stays.
+            static const std::regex redeclarationRegex(
+                R"(^\s*(?:out|in)\s+(?:(?:high|medium|low)p\s+)?float\s+gl_(?:Clip|Cull)Distance\[[0-9]+\];\s*$)");
+
+            String result;
+            result.reserve(glslCode.size());
+            SizeT lineStart = 0;
+            Bool firstLine = true;
+            while (lineStart <= glslCode.size()) {
+                SizeT lineEnd = glslCode.find('\n', lineStart);
+                const Bool lastLine = lineEnd == String::npos;
+                String line = glslCode.substr(lineStart, lastLine ? String::npos : lineEnd - lineStart);
+
+                if (!std::regex_match(line, redeclarationRegex)) {
+                    if (!firstLine) {
+                        result += '\n';
+                    }
+                    result += line;
+                    firstLine = false;
+                }
+                if (lastLine) {
+                    break;
+                }
+                lineStart = lineEnd + 1;
+            }
+            return result;
+        }
     } // namespace PrgramImpl
 
     namespace Utils {
@@ -448,4 +487,407 @@ namespace MobileGL::MG_Backend::DirectGLES {
             }
         }
     } // namespace Utils
+
+    // ---- Client-format readback conversion helpers -------------------------------------------------
+    // ReadPixels/GetTexImage read a guaranteed wide RGBA(_INTEGER) layout from the ES driver and repack
+    // it on the CPU into the client's (format, type) layout. Everything here is pure byte shuffling so
+    // unit tests can assert the exact packed words; field positions follow GL 3.3 table 3.6 and mirror
+    // the GL CTS packed_pixels oracle (glcPackedPixelsTests.cpp pack_UNSIGNED_* helpers).
+    namespace ReadbackImpl {
+        using MG_Util::DecodeHalfBitsToFloat;
+        using MG_Util::EncodeFloatToHalfBits;
+
+        Bool GetReadbackChannelMapping(GLenum format, ReadbackChannelMapping& outMapping) {
+            switch (format) {
+            case GL_RED:          outMapping = {{0, 0, 0, 0}, 1, false}; return true;
+            case GL_RED_INTEGER:  outMapping = {{0, 0, 0, 0}, 1, true};  return true;
+            // Desktop-GL single-channel client formats (GL CTS packed_pixels rgba8_format_green/blue):
+            // the destination holds one component sourced from the named channel of the wide RGBA read.
+            // GL_ALPHA is mapped here from the raw enum because the state layer folds it into Red for the
+            // legacy alpha-texture upload hack.
+            case GL_GREEN:         outMapping = {{1, 0, 0, 0}, 1, false}; return true;
+            case GL_GREEN_INTEGER: outMapping = {{1, 0, 0, 0}, 1, true};  return true;
+            case GL_BLUE:          outMapping = {{2, 0, 0, 0}, 1, false}; return true;
+            case GL_BLUE_INTEGER:  outMapping = {{2, 0, 0, 0}, 1, true};  return true;
+            case GL_ALPHA:         outMapping = {{3, 0, 0, 0}, 1, false}; return true;
+            case GL_ALPHA_INTEGER: outMapping = {{3, 0, 0, 0}, 1, true};  return true;
+            case GL_RG:           outMapping = {{0, 1, 0, 0}, 2, false}; return true;
+            case GL_RG_INTEGER:   outMapping = {{0, 1, 0, 0}, 2, true};  return true;
+            case GL_RGB:          outMapping = {{0, 1, 2, 0}, 3, false}; return true;
+            case GL_RGB_INTEGER:  outMapping = {{0, 1, 2, 0}, 3, true};  return true;
+            case GL_BGR:          outMapping = {{2, 1, 0, 0}, 3, false}; return true;
+            case GL_BGR_INTEGER:  outMapping = {{2, 1, 0, 0}, 3, true};  return true;
+            case GL_RGBA:         outMapping = {{0, 1, 2, 3}, 4, false}; return true;
+            case GL_RGBA_INTEGER: outMapping = {{0, 1, 2, 3}, 4, true};  return true;
+            case GL_BGRA:         outMapping = {{2, 1, 0, 3}, 4, false}; return true;
+            case GL_BGRA_INTEGER: outMapping = {{2, 1, 0, 3}, 4, true};  return true;
+            default:
+                return false;
+            }
+        }
+
+        Bool GetPackedReadbackLayout(GLenum type, PackedReadbackLayout& out) {
+            switch (type) {
+            // Non-REV types pack the first format component starting at the most significant bit,
+            // *_REV types starting at the least significant bit (GL CTS pack_UNSIGNED_SHORT_5_6_5:
+            // R bits 15-11; pack_UNSIGNED_SHORT_1_5_5_5_REV: R bits 4-0, A bit 15).
+            case GL_UNSIGNED_BYTE_3_3_2:          out = {3, {3, 3, 2, 0},    {5, 2, 0, 0},    1, false}; return true;
+            case GL_UNSIGNED_BYTE_2_3_3_REV:      out = {3, {3, 3, 2, 0},    {0, 3, 6, 0},    1, false}; return true;
+            case GL_UNSIGNED_SHORT_5_6_5:         out = {3, {5, 6, 5, 0},    {11, 5, 0, 0},   2, false}; return true;
+            case GL_UNSIGNED_SHORT_5_6_5_REV:     out = {3, {5, 6, 5, 0},    {0, 5, 11, 0},   2, false}; return true;
+            case GL_UNSIGNED_SHORT_4_4_4_4:       out = {4, {4, 4, 4, 4},    {12, 8, 4, 0},   2, false}; return true;
+            case GL_UNSIGNED_SHORT_4_4_4_4_REV:   out = {4, {4, 4, 4, 4},    {0, 4, 8, 12},   2, false}; return true;
+            case GL_UNSIGNED_SHORT_5_5_5_1:       out = {4, {5, 5, 5, 1},    {11, 6, 1, 0},   2, false}; return true;
+            case GL_UNSIGNED_SHORT_1_5_5_5_REV:   out = {4, {5, 5, 5, 1},    {0, 5, 10, 15},  2, false}; return true;
+            case GL_UNSIGNED_INT_8_8_8_8:         out = {4, {8, 8, 8, 8},    {24, 16, 8, 0},  4, false}; return true;
+            case GL_UNSIGNED_INT_8_8_8_8_REV:     out = {4, {8, 8, 8, 8},    {0, 8, 16, 24},  4, false}; return true;
+            case GL_UNSIGNED_INT_10_10_10_2:      out = {4, {10, 10, 10, 2}, {22, 12, 2, 0},  4, false}; return true;
+            case GL_UNSIGNED_INT_2_10_10_10_REV:  out = {4, {10, 10, 10, 2}, {0, 10, 20, 30}, 4, false}; return true;
+            // Packed-float RGB types: fields hold unsigned small floats; 5_9_9_9_REV's shared 5-bit
+            // exponent (bits 31-27) is emitted by EncodeSharedExponentRGB9E5, not a component field.
+            case GL_UNSIGNED_INT_10F_11F_11F_REV: out = {3, {11, 11, 10, 0}, {0, 11, 22, 0},  4, true};  return true;
+            case GL_UNSIGNED_INT_5_9_9_9_REV:     out = {3, {9, 9, 9, 0},    {0, 9, 18, 0},   4, true};  return true;
+            default:
+                return false;
+            }
+        }
+
+        SizeT GetReadbackComponentSize(GLenum type) {
+            PackedReadbackLayout packedLayout{};
+            if (GetPackedReadbackLayout(type, packedLayout)) {
+                return packedLayout.byteSize;
+            }
+            switch (type) {
+            case GL_UNSIGNED_BYTE:
+            case GL_BYTE:
+                return 1;
+            case GL_UNSIGNED_SHORT:
+            case GL_SHORT:
+            case GL_HALF_FLOAT:
+                return 2;
+            case GL_UNSIGNED_INT:
+            case GL_INT:
+            case GL_FLOAT:
+                return 4;
+            default:
+                return 0;
+            }
+        }
+
+        SizeT GetReadbackDstPixelSize(const ReadbackChannelMapping& mapping, GLenum type) {
+            PackedReadbackLayout packedLayout{};
+            if (GetPackedReadbackLayout(type, packedLayout)) {
+                if (packedLayout.fieldCount != mapping.channelCount) {
+                    return 0; // 3-field packed types pair with 3-component formats only, 4 with 4
+                }
+                if (mapping.isInteger && packedLayout.isFloatPacked) {
+                    return 0; // packed-float RGB types never pair with integer formats
+                }
+                return packedLayout.byteSize;
+            }
+            if (mapping.isInteger && (type == GL_FLOAT || type == GL_HALF_FLOAT)) {
+                return 0;
+            }
+            const SizeT componentSize = GetReadbackComponentSize(type);
+            return componentSize == 0 ? 0 : static_cast<SizeT>(mapping.channelCount) * componentSize;
+        }
+
+        namespace {
+            void WritePackedReadbackWord(Uint8* dst, Uint32 word, SizeT byteSize) {
+                switch (byteSize) {
+                case 1: {
+                    const auto out = static_cast<Uint8>(word);
+                    Memcpy(dst, &out, sizeof(out));
+                    break;
+                }
+                case 2: {
+                    const auto out = static_cast<Uint16>(word);
+                    Memcpy(dst, &out, sizeof(out));
+                    break;
+                }
+                default:
+                    Memcpy(dst, &word, sizeof(word));
+                    break;
+                }
+            }
+        } // namespace
+
+        // Shared encoders live in MG_Util/Math/SmallFloat.h so the upload conversion
+        // (PixelStoreProcessor) uses byte-identical packing; kept exported here for unit tests.
+        Uint32 EncodeFloatToUnsignedF11(Float value) { return MG_Util::EncodeFloatToUnsignedF11(value); }
+        Uint32 EncodeFloatToUnsignedF10(Float value) { return MG_Util::EncodeFloatToUnsignedF10(value); }
+        Uint32 EncodeSharedExponentRGB9E5(const Float rgb[3]) { return MG_Util::EncodeSharedExponentRGB9E5(rgb); }
+
+        void ConvertWideReadbackRow(const Uint8* src, Uint8* dst, SizeT width, GLenum wideType,
+                                    const ReadbackChannelMapping& mapping, GLenum type) {
+            PackedReadbackLayout packedLayout{};
+            const Bool isPacked = GetPackedReadbackLayout(type, packedLayout);
+            const SizeT dstComponentSize = GetReadbackComponentSize(type);
+            const SizeT dstPixelBytes = GetReadbackDstPixelSize(mapping, type);
+            const SizeT srcPixelBytes = 4 * GetReadbackComponentSize(wideType);
+
+            for (SizeT col = 0; col < width; ++col) {
+                const Uint8* srcPixel = src + col * srcPixelBytes;
+                Uint8* dstPixel = dst + col * dstPixelBytes;
+                if (mapping.isInteger) {
+                    Int64 srcValues[4];
+                    for (Int c = 0; c < 4; ++c) {
+                        srcValues[c] = wideType == GL_INT
+                                           ? static_cast<Int64>(reinterpret_cast<const Int32*>(srcPixel)[c])
+                                           : static_cast<Int64>(reinterpret_cast<const Uint32*>(srcPixel)[c]);
+                    }
+                    if (isPacked) {
+                        // Integer sources clamp each component to the unsigned range of its field
+                        // (GL 3.3 section 4.3.1 final conversion).
+                        Uint32 word = 0;
+                        for (Int ch = 0; ch < packedLayout.fieldCount; ++ch) {
+                            const Int64 fieldMax = (Int64{1} << packedLayout.width[ch]) - 1;
+                            const auto v = static_cast<Uint32>(
+                                std::clamp<Int64>(srcValues[mapping.sourceChannel[ch]], 0, fieldMax));
+                            word |= v << packedLayout.shift[ch];
+                        }
+                        WritePackedReadbackWord(dstPixel, word, packedLayout.byteSize);
+                    } else {
+                        for (Int ch = 0; ch < mapping.channelCount; ++ch) {
+                            const Int64 v = srcValues[mapping.sourceChannel[ch]];
+                            Uint8* dstComponent = dstPixel + static_cast<SizeT>(ch) * dstComponentSize;
+                            switch (type) {
+                            case GL_UNSIGNED_BYTE:
+                                *dstComponent = static_cast<Uint8>(std::clamp<Int64>(v, 0, 255));
+                                break;
+                            case GL_BYTE: {
+                                const auto out = static_cast<Int8>(std::clamp<Int64>(v, -128, 127));
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            case GL_UNSIGNED_SHORT: {
+                                const auto out = static_cast<Uint16>(std::clamp<Int64>(v, 0, 65535));
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            case GL_SHORT: {
+                                const auto out = static_cast<Int16>(std::clamp<Int64>(v, -32768, 32767));
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            case GL_UNSIGNED_INT: {
+                                const auto out = static_cast<Uint32>(std::clamp<Int64>(v, 0, 4294967295LL));
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            case GL_INT: {
+                                const auto out =
+                                    static_cast<Int32>(std::clamp<Int64>(v, -2147483648LL, 2147483647LL));
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            default:
+                                break;
+                            }
+                        }
+                    }
+                } else {
+                    Float srcValues[4];
+                    switch (wideType) {
+                    case GL_UNSIGNED_BYTE:
+                        for (Int c = 0; c < 4; ++c) {
+                            srcValues[c] = static_cast<Float>(srcPixel[c]) / 255.0f;
+                        }
+                        break;
+                    case GL_BYTE:
+                        for (Int c = 0; c < 4; ++c) {
+                            srcValues[c] = std::max(
+                                static_cast<Float>(reinterpret_cast<const Int8*>(srcPixel)[c]) / 127.0f, -1.0f);
+                        }
+                        break;
+                    case GL_UNSIGNED_SHORT:
+                        for (Int c = 0; c < 4; ++c) {
+                            srcValues[c] =
+                                static_cast<Float>(reinterpret_cast<const Uint16*>(srcPixel)[c]) / 65535.0f;
+                        }
+                        break;
+                    case GL_SHORT:
+                        for (Int c = 0; c < 4; ++c) {
+                            srcValues[c] = std::max(
+                                static_cast<Float>(reinterpret_cast<const Int16*>(srcPixel)[c]) / 32767.0f, -1.0f);
+                        }
+                        break;
+                    case GL_HALF_FLOAT:
+                        for (Int c = 0; c < 4; ++c) {
+                            srcValues[c] = DecodeHalfBitsToFloat(reinterpret_cast<const Uint16*>(srcPixel)[c]);
+                        }
+                        break;
+                    default: // GL_FLOAT
+                        for (Int c = 0; c < 4; ++c) {
+                            srcValues[c] = reinterpret_cast<const Float*>(srcPixel)[c];
+                        }
+                        break;
+                    }
+                    if (isPacked) {
+                        Uint32 word = 0;
+                        if (packedLayout.isFloatPacked) {
+                            const Float fields[3] = {srcValues[mapping.sourceChannel[0]],
+                                                     srcValues[mapping.sourceChannel[1]],
+                                                     srcValues[mapping.sourceChannel[2]]};
+                            word = type == GL_UNSIGNED_INT_5_9_9_9_REV
+                                       ? EncodeSharedExponentRGB9E5(fields)
+                                       : (EncodeFloatToUnsignedF11(fields[0]) << packedLayout.shift[0]) |
+                                             (EncodeFloatToUnsignedF11(fields[1]) << packedLayout.shift[1]) |
+                                             (EncodeFloatToUnsignedF10(fields[2]) << packedLayout.shift[2]);
+                        } else {
+                            // Normalized encode: round(clamp(v, 0, 1) * (2^bits - 1)) into each field.
+                            for (Int ch = 0; ch < packedLayout.fieldCount; ++ch) {
+                                const auto fieldMax = static_cast<Float>((1u << packedLayout.width[ch]) - 1u);
+                                const auto v = static_cast<Uint32>(std::llround(
+                                    std::clamp(srcValues[mapping.sourceChannel[ch]], 0.0f, 1.0f) * fieldMax));
+                                word |= v << packedLayout.shift[ch];
+                            }
+                        }
+                        WritePackedReadbackWord(dstPixel, word, packedLayout.byteSize);
+                    } else {
+                        for (Int ch = 0; ch < mapping.channelCount; ++ch) {
+                            const Float v = srcValues[mapping.sourceChannel[ch]];
+                            Uint8* dstComponent = dstPixel + static_cast<SizeT>(ch) * dstComponentSize;
+                            switch (type) {
+                            case GL_UNSIGNED_BYTE:
+                                *dstComponent =
+                                    static_cast<Uint8>(std::llround(std::clamp(v, 0.0f, 1.0f) * 255.0));
+                                break;
+                            case GL_BYTE: {
+                                const auto out =
+                                    static_cast<Int8>(std::llround(std::clamp(v, -1.0f, 1.0f) * 127.0));
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            case GL_UNSIGNED_SHORT: {
+                                const auto out =
+                                    static_cast<Uint16>(std::llround(std::clamp(v, 0.0f, 1.0f) * 65535.0));
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            case GL_SHORT: {
+                                const auto out =
+                                    static_cast<Int16>(std::llround(std::clamp(v, -1.0f, 1.0f) * 32767.0));
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            case GL_UNSIGNED_INT: {
+                                const auto out = static_cast<Uint32>(
+                                    std::llround(static_cast<Double>(std::clamp(v, 0.0f, 1.0f)) * 4294967295.0));
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            case GL_INT: {
+                                const auto out = static_cast<Int32>(
+                                    std::llround(static_cast<Double>(std::clamp(v, -1.0f, 1.0f)) * 2147483647.0));
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            case GL_FLOAT:
+                                Memcpy(dstComponent, &v, sizeof(v));
+                                break;
+                            case GL_HALF_FLOAT: {
+                                const Uint16 out = EncodeFloatToHalfBits(v);
+                                Memcpy(dstComponent, &out, sizeof(out));
+                                break;
+                            }
+                            default:
+                                break;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        static SizeT AlignReadbackRow(SizeT rowBytes, Int alignment) {
+            const SizeT align = alignment > 0 ? static_cast<SizeT>(alignment) : 1;
+            return (rowBytes + align - 1) / align * align;
+        }
+
+    // Repacks wide RGBA(_INTEGER) rows into the client's (format, type) layout, honoring the
+        // client-side PACK parameters and the bound pixel-pack buffer. `wide` holds
+        // `sliceHeight * sliceCount` rows of `width` texels (slice-major, tightly stacked),
+        // 4 components x GetReadbackComponentSize(wideType) bytes each.
+        // applyPackImageParams: GL_PACK_IMAGE_HEIGHT / GL_PACK_SKIP_IMAGES apply only to GetTexImage
+        // of 3D/array images; ReadPixels and 2D GetTexImage ignore them (GL 3.3 sections 4.3.1, 6.1.4).
+        // Per the GL addressing rules, slice k row j lands at
+        // SKIP_IMAGES*imageStride + SKIP_ROWS*rowStride + SKIP_PIXELS*pixelBytes
+        //   + k*imageStride + j*rowStride, with imageStride = max(IMAGE_HEIGHT, sliceHeight)*rowStride.
+        Bool StoreWideRowsToClient(const Uint8* wide, GLenum wideType, GLsizei width, GLsizei sliceHeight,
+                                   GLsizei sliceCount, const ReadbackChannelMapping& mapping, GLenum type,
+                                   void* pixels, Bool applyPackImageParams) {
+        const SizeT dstPixelBytes = GetReadbackDstPixelSize(mapping, type);
+        if (dstPixelBytes == 0) {
+            return false;
+        }
+        PackedReadbackLayout packedLayout{};
+        const Bool isPackedType = GetPackedReadbackLayout(type, packedLayout);
+        const SizeT dstComponentSize = GetReadbackComponentSize(type);
+
+        const auto& pixelPackBufferObject =
+            MG_State::pGLContext->GetBufferBindingSlot(BufferTarget::PixelPack).GetBoundObject();
+
+        // Destination layout is computed from the client-side PACK parameters; only the actual pixel
+        // rows are written so skip regions of the destination stay untouched.
+        const auto packParams = MG_State::pGLContext->GetPixelStoreParameters(false);
+        const SizeT rowPixels = static_cast<SizeT>(packParams.RowLength > 0 ? packParams.RowLength : width);
+        const SizeT dstRowStride = AlignReadbackRow(rowPixels * dstPixelBytes, packParams.Alignment);
+        const SizeT imageRows =
+            applyPackImageParams && packParams.ImageHeight > 0
+                ? static_cast<SizeT>(packParams.ImageHeight)
+                : static_cast<SizeT>(sliceHeight);
+        const SizeT dstImageStride = imageRows * dstRowStride;
+        const SizeT skipImages =
+            applyPackImageParams ? static_cast<SizeT>(std::max(packParams.SkipImages, 0)) : SizeT{0};
+        const SizeT dstSkipOffset = skipImages * dstImageStride +
+                                    static_cast<SizeT>(std::max(packParams.SkipRows, 0)) * dstRowStride +
+                                    static_cast<SizeT>(std::max(packParams.SkipPixels, 0)) * dstPixelBytes;
+        const SizeT dstRowBytes = static_cast<SizeT>(width) * dstPixelBytes;
+
+        const SizeT pboBaseOffset = reinterpret_cast<SizeT>(pixels); // with a PBO, `pixels` is an offset
+        if (pixelPackBufferObject) {
+            const SizeT requiredSize = pboBaseOffset + dstSkipOffset +
+                                    static_cast<SizeT>(sliceCount - 1) * dstImageStride +
+                                    static_cast<SizeT>(sliceHeight - 1) * dstRowStride + dstRowBytes;
+            if (requiredSize > pixelPackBufferObject->GetSize()) {
+                MGLOG_E("Readback conversion: pixel pack buffer is too small");
+                return true;
+            }
+        }
+
+        const SizeT srcComponentSize = GetReadbackComponentSize(wideType);
+        const SizeT srcPixelBytes = 4 * srcComponentSize;
+        Vector<Uint8> convertedRow(dstRowBytes);
+
+        for (GLsizei slice = 0; slice < sliceCount; ++slice) {
+            for (GLsizei row = 0; row < sliceHeight; ++row) {
+                const SizeT flatRow = static_cast<SizeT>(slice) * static_cast<SizeT>(sliceHeight) +
+                                   static_cast<SizeT>(row);
+                const Uint8* srcRow = wide + flatRow * static_cast<SizeT>(width) * srcPixelBytes;
+                ConvertWideReadbackRow(srcRow, convertedRow.data(), static_cast<SizeT>(width), wideType,
+                                                  mapping, type);
+
+                if (packParams.SwapBytes) {
+                    const SizeT groupSize = isPackedType ? packedLayout.byteSize : dstComponentSize;
+                    if (groupSize > 1) {
+                        for (SizeT offset = 0; offset + groupSize <= dstRowBytes; offset += groupSize) {
+                            std::reverse(convertedRow.data() + offset, convertedRow.data() + offset + groupSize);
+                        }
+                    }
+                }
+
+                const SizeT dstOffset = dstSkipOffset + static_cast<SizeT>(slice) * dstImageStride +
+                                     static_cast<SizeT>(row) * dstRowStride;
+                if (pixelPackBufferObject) {
+                    pixelPackBufferObject->WritebackFromBackend({convertedRow.data(), dstRowBytes},
+                                                             pboBaseOffset + dstOffset);
+                } else {
+                    Memcpy(static_cast<Uint8*>(pixels) + dstOffset, convertedRow.data(), dstRowBytes);
+                }
+            }
+        }
+            return true;
+        }
+    } // namespace ReadbackImpl
 } // namespace MobileGL::MG_Backend::DirectGLES

MobileGL/MG_Backend/DirectGLES/Utils.h

@@ -45,6 +45,59 @@ namespace MobileGL::MG_Backend::DirectGLES {
 
     namespace FramebufferImpl {} // namespace FramebufferImpl
 
+    // Pure CPU helpers of the client-format readback conversion (ReadPixels/GetTexImage repack a wide
+    // RGBA(_INTEGER) read into the caller's (format, type) layout). Kept context-free so unit tests can
+    // exercise the exact packing the GL CTS packed_pixels oracle compares against.
+    namespace ReadbackImpl {
+        struct ReadbackChannelMapping {
+            Int sourceChannel[4]; // RGBA source channel feeding each destination component
+            Int channelCount;     // destination component count
+            Bool isInteger;
+        };
+        Bool GetReadbackChannelMapping(GLenum format, ReadbackChannelMapping& outMapping);
+
+        // Byte size of one destination component of `type`; packed types report the packed word size.
+        // 0 = type not supported by the conversion path.
+        SizeT GetReadbackComponentSize(GLenum type);
+
+        // Bit-field layout of a GL packed pixel type. width/shift are indexed in the client format's
+        // component order (matching ReadbackChannelMapping); shift is the LSB position of the field in
+        // the packed word: non-REV types pack the first component from the MSB, *_REV types from the
+        // LSB (GL 3.3 table 3.6; field positions mirror the GL CTS glcPackedPixelsTests pack_* oracle).
+        struct PackedReadbackLayout {
+            Int fieldCount;     // format components stored in the packed word
+            Int width[4];       // bit width of each component's field
+            Int shift[4];       // LSB bit position of each component's field
+            SizeT byteSize;     // packed word size in bytes (1, 2 or 4)
+            Bool isFloatPacked; // 10F_11F_11F_REV / 5_9_9_9_REV: fields hold unsigned small floats
+        };
+        Bool GetPackedReadbackLayout(GLenum type, PackedReadbackLayout& out);
+
+        // Unsigned small-float encoders (EXT_packed_float / EXT_texture_shared_exponent semantics).
+        Uint32 EncodeFloatToUnsignedF11(Float value);
+        Uint32 EncodeFloatToUnsignedF10(Float value);
+        Uint32 EncodeSharedExponentRGB9E5(const Float rgb[3]);
+
+        // Destination bytes per pixel for a (format mapping, type) readback pair; 0 when the pair is
+        // not convertible (unknown type, packed field count != format component count, floating-point
+        // or packed-float type with an integer format).
+        SizeT GetReadbackDstPixelSize(const ReadbackChannelMapping& mapping, GLenum type);
+
+        // Repacks one row of wide RGBA(_INTEGER) texels (4 components of wideType each) into the
+        // client's (format, type) layout. src holds width * 4 * GetReadbackComponentSize(wideType)
+        // bytes, dst receives width * GetReadbackDstPixelSize(mapping, type) bytes.
+        void ConvertWideReadbackRow(const Uint8* src, Uint8* dst, SizeT width, GLenum wideType,
+                                    const ReadbackChannelMapping& mapping, GLenum type);
+
+        // Stores wide RGBA(_INTEGER) rows into the client pointer or the bound PACK pixel buffer,
+        // honoring the client-side PACK pixel-store parameters (row length, alignment, skips,
+        // swap-bytes, and - when applyPackImageParams - image height/skip images). Shared by the
+        // DirectGLES and DirectVulkan readback conversion paths.
+        Bool StoreWideRowsToClient(const Uint8* wide, GLenum wideType, GLsizei width, GLsizei sliceHeight,
+                                   GLsizei sliceCount, const ReadbackChannelMapping& mapping, GLenum type,
+                                   void* pixels, Bool applyPackImageParams);
+    } // namespace ReadbackImpl
+
     namespace PrgramImpl {
         String ProcessOutColorLocations(const String& glslCode);
         String ForceSupporterOutput(const String& glslCode);
@@ -52,6 +105,7 @@ namespace MobileGL::MG_Backend::DirectGLES {
                                         Uint32 unormOutputMask);
         String ForceFlatIntegerVaryings(const String& glslCode, GLenum shaderType);
         String RemoveLayoutBinding(const String& glslCode);
+        String RemoveClipDistanceRedeclaration(const String& glslCode);
     } // namespace PrgramImpl
 
     namespace Utils {

MobileGL/MG_Backend/DirectVulkan/BackendObject_DirectVulkan.cpp

@@ -140,6 +140,20 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             case TextureInternalFormat::RGB:
             case TextureInternalFormat::RGB8:
                 return TextureInternalFormat::RGBA8;
+            // Legacy low-bit-depth formats with no (or rarely supported) native Vulkan
+            // encoding; a wider normalized fallback keeps at least the required precision.
+            case TextureInternalFormat::R3G3B2:
+            case TextureInternalFormat::RGB4:
+            case TextureInternalFormat::RGB5:
+            case TextureInternalFormat::RGBA2:
+            case TextureInternalFormat::RGBA4:
+            case TextureInternalFormat::RGB5A1:
+                return TextureInternalFormat::RGBA8;
+            case TextureInternalFormat::RGB10:
+                return TextureInternalFormat::RGB10A2;
+            case TextureInternalFormat::RGB12:
+            case TextureInternalFormat::RGBA12:
+                return TextureInternalFormat::RGBA16;
             case TextureInternalFormat::SRGB8:
                 return TextureInternalFormat::SRGB8Alpha8;
             case TextureInternalFormat::RGB8Snorm:
@@ -397,8 +411,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
         if (!handle.Handle || (handle.Backend != WindowBackend::Android &&
                                handle.Backend != WindowBackend::X11 &&
-                               handle.Backend != WindowBackend::MetalLayer)) {
-            MGLOG_E("DirectVulkan backend only supports Android, X11, and CAMetalLayer native windows");
+                               handle.Backend != WindowBackend::MetalLayer &&
+                               handle.Backend != WindowBackend::Win32)) {
+            MGLOG_E("DirectVulkan backend only supports Android, X11, CAMetalLayer, and Win32 native windows");
             return false;
         }
 
@@ -488,14 +503,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     .TargetGLSLVersion = {4, 6, 0},
                     // Baseline advertisement (no shader subgroup, no timer queries); a
                     // live backend reconciles its copy in UpdateAdvertisedExtensions.
-                    .Extensions = BuildAdvertisedExtensions(false, false),
+                    .Extensions = BuildAdvertisedExtensions(false, false, false),
                     .IsCompatibilityProfile = false
                 },
             .StaticBackendCapability = {.AllowVSOnlyPrograms = false}};
         return rendererInfo;
     }
 
-    Vector<GLExtension> BuildAdvertisedExtensions(Bool shaderSubgroupSupported, Bool timerQueriesSupported) {
+    Vector<GLExtension> BuildAdvertisedExtensions(Bool shaderSubgroupSupported, Bool timerQueriesSupported,
+                                                  Bool anisotropicFilteringSupported) {
         Vector<GLExtension> extensions = {V_OpenGL30, V_OpenGL31, V_OpenGL32,
                                           V_OpenGL33, 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,
@@ -503,7 +519,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                           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_direct_state_access,
+                                          E_GL_ARB_clear_texture, E_GL_ARB_direct_state_access,
                                           E_GL_ARB_shader_draw_parameters, E_GL_ARB_gpu_shader_int64, E_GL_KHR_debug,
                                           E_GL_ARB_gpu_shader5, E_GL_ARB_multi_bind, E_GL_ARB_shading_language_420pack,
                                           E_GL_ARB_vertex_attrib_binding, E_GL_ARB_shader_image_size};
@@ -516,6 +532,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         if (timerQueriesSupported && !MG_Config::Features.DisableTimerQuery) {
             extensions.push_back(E_GL_ARB_timer_query);
         }
+        // Only advertised when the samplerAnisotropy device feature was granted: without it the
+        // sampler state is accepted but never applied, and an app trusting the string (LWJGL builds
+        // GLCapabilities from it) would think it enabled anisotropic filtering.
+        if (anisotropicFilteringSupported) {
+            extensions.push_back(E_GL_EXT_texture_filter_anisotropic);
+            extensions.push_back(E_GL_ARB_texture_filter_anisotropic);
+        }
         return extensions;
     }
 
@@ -630,7 +653,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // run without a renderer; no timer query is advertised then. Rebuilding
         // the whole list keeps re-runs idempotent.
         m_rendererInfo.RendererGLInfo.Extensions = BuildAdvertisedExtensions(
-            m_vulkanCaps.SupportsShaderSubgroup, pVulkanRenderer && pVulkanRenderer->IsTimerQuerySupported());
+            m_vulkanCaps.SupportsShaderSubgroup, pVulkanRenderer && pVulkanRenderer->IsTimerQuerySupported(),
+            pVulkanRenderer && pVulkanRenderer->IsSamplerAnisotropySupported());
     }
 
     void BackendObject_DirectVulkan::UpdateDynamicBackendParameters() {
@@ -680,6 +704,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         m_dynamicParameters.UniformBufferOffsetAlignment = m_vulkanCaps.UniformBufferOffsetAlignment;
         m_dynamicParameters.AliasedLineWidthRangeMin = m_vulkanCaps.AliasedLineWidthRangeMin;
         m_dynamicParameters.AliasedLineWidthRangeMax = m_vulkanCaps.AliasedLineWidthRangeMax;
+        // Without the samplerAnisotropy feature the limit is unusable, so report 1.0 (no anisotropy)
+        // rather than a maximum the sampler manager will never apply.
+        m_dynamicParameters.MaxTextureMaxAnisotropy =
+            (pVulkanRenderer && pVulkanRenderer->IsSamplerAnisotropySupported()) ? m_vulkanCaps.MaxSamplerAnisotropy
+                                                                                : 1.0f;
         m_dynamicParameters.SmoothLineWidthRangeMin = m_vulkanCaps.SmoothLineWidthRangeMin;
         m_dynamicParameters.SmoothLineWidthRangeMax = m_vulkanCaps.SmoothLineWidthRangeMax;
         m_dynamicParameters.SmoothLineWidthGranularity = m_vulkanCaps.SmoothLineWidthGranularity;
@@ -732,9 +761,24 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         m_dynamicParameters.MaxTextureBufferSize = m_vulkanCaps.MaxTextureBufferSize;
         m_dynamicParameters.MaxUniformBufferBindings = m_vulkanCaps.MaxUniformBufferBindings;
         m_dynamicParameters.MaxUniformBlockSize = m_vulkanCaps.MaxUniformBlockSize;
-        m_dynamicParameters.MaxImageUnits = std::min(m_vulkanCaps.MaxImageUnits, maxSupportedTextureUnits);
-        m_dynamicParameters.MaxCombinedImageUniforms = m_vulkanCaps.MaxCombinedImageUniforms;
-        m_dynamicParameters.MaxComputeImageUniforms = m_vulkanCaps.MaxComputeImageUniforms;
+        m_dynamicParameters.MaxImageUnits =
+            std::max(std::min(m_vulkanCaps.MaxImageUnits, maxSupportedTextureUnits), 0);
+        m_dynamicParameters.MaxCombinedImageUniforms = std::max(m_vulkanCaps.MaxCombinedImageUniforms, 0);
+        const Int maxPerStageImageUniforms =
+            std::min(m_dynamicParameters.MaxImageUnits, m_dynamicParameters.MaxCombinedImageUniforms);
+        // Vulkan uses one descriptor limit for every stage, but non-compute stores/atomics are
+        // optional device features. VulkanRenderer enables each feature whenever the physical
+        // device reports it, so these are the exact limits the logical device can compile and run.
+        m_dynamicParameters.MaxVertexImageUniforms =
+            m_vulkanCaps.SupportsVertexPipelineStoresAndAtomics ? maxPerStageImageUniforms : 0;
+        m_dynamicParameters.MaxGeometryImageUniforms =
+            m_vulkanCaps.SupportsVertexPipelineStoresAndAtomics && m_vulkanCaps.SupportsGeometryShader
+                ? maxPerStageImageUniforms
+                : 0;
+        m_dynamicParameters.MaxFragmentImageUniforms =
+            m_vulkanCaps.SupportsFragmentStoresAndAtomics ? maxPerStageImageUniforms : 0;
+        m_dynamicParameters.MaxComputeImageUniforms =
+            std::min(std::max(m_vulkanCaps.MaxComputeImageUniforms, 0), maxPerStageImageUniforms);
         const Int maxSupportedDrawBuffers =
             static_cast<Int>(MG_State::GLState::FramebufferObject::MAX_DRAW_BUFFERS);
         m_dynamicParameters.MaxDrawBuffers = std::min(m_vulkanCaps.MaxDrawBuffers, maxSupportedDrawBuffers);
@@ -765,5 +809,32 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     m_vulkanCaps.MaxShaderStorageBlockSize,
                     m_dynamicParameters.MaxShaderStorageBlockSize);
         }
+        switch (m_vulkanCaps.VendorId) {
+        case 0x5143u: // VK_VENDOR_ID: Qualcomm
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Qualcomm;
+            break;
+        case 0x13B5u: // ARM
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Arm;
+            break;
+        case 0x10DEu: // NVIDIA
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Nvidia;
+            break;
+        case 0x1002u: // AMD
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Amd;
+            break;
+        case 0x8086u: // Intel
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Intel;
+            break;
+        case 0x1010u: // Imagination
+            m_dynamicParameters.GpuVendor = GpuVendorKind::ImgTec;
+            break;
+        case 0x10005u: // Mesa software (lavapipe)
+        case 0x1AE0u:  // Google (SwiftShader)
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Software;
+            break;
+        default:
+            m_dynamicParameters.GpuVendor = GpuVendorKind::Unknown;
+            break;
+        }
     }
 } // namespace MobileGL::MG_Backend::DirectVulkan

MobileGL/MG_Backend/DirectVulkan/BackendObject_DirectVulkan.h

@@ -73,7 +73,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     // a device with the given raw capabilities. The MOBILEGL_DISABLE_SUBGROUP and
     // 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);
+    Vector<GLExtension> BuildAdvertisedExtensions(Bool shaderSubgroupSupported, Bool timerQueriesSupported,
+                                                  Bool anisotropicFilteringSupported);
 
     // 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

@@ -20,7 +20,8 @@
 #include <spirv_reflect.h>
 
 namespace MobileGL::MG_Backend::DirectVulkan {
-    UniquePtr<VulkanRenderer> pVulkanRenderer = nullptr;
+    // Leak-at-exit storage; see GlobalObjects.cpp.
+    UniquePtr<VulkanRenderer>& pVulkanRenderer = *new UniquePtr<VulkanRenderer>();
 
     namespace {
         // Generation of the live VulkanRenderer instance, mirroring

MobileGL/MG_Backend/DirectVulkan/DirectVulkan.h

@@ -12,7 +12,7 @@
 #include "Renderer/VulkanRenderer.h"
 
 namespace MobileGL::MG_Backend::DirectVulkan {
-    extern UniquePtr<VulkanRenderer> pVulkanRenderer;
+    extern UniquePtr<VulkanRenderer>& pVulkanRenderer;
 
     // Generation of the live VulkanRenderer instance, mirroring DirectGLES's
     // g_syncContextGeneration. BackendObject_DirectVulkan bumps it wherever

MobileGL/MG_Backend/DirectVulkan/Renderer/PipelineFactory.cpp

@@ -8,6 +8,7 @@
 
 #include "PipelineFactory.h"
 
+
 namespace MobileGL::MG_Backend::DirectVulkan {
     static const char* PrimitiveTopologyToString(VkPrimitiveTopology topology) {
         switch (topology) {
@@ -108,6 +109,81 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                   "vkCreatePipelineCache");
     }
 
+    // Must be called once, before any pipeline is created: the flag is not part of the
+    // pipeline hash, so flipping it mid-life would serve cached pipelines built under the
+    // old value.
+    void PipelineFactory::SetSuppressBlendedDepthWrite(Bool enabled) {
+        s_suppressBlendedDepthWrite = enabled;
+    }
+
+    Bool PipelineFactory::ShouldSuppressBlendedDepthWriteForDevice(MG_Config::QuirkOverride quirkOverride,
+                                                                   Uint32 vendorId) {
+        static constexpr Uint32 kVendorIdQualcomm = 0x5143;
+        switch (quirkOverride) {
+        case MG_Config::QuirkOverride::ForceOn:
+            return true;
+        case MG_Config::QuirkOverride::ForceOff:
+            return false;
+        case MG_Config::QuirkOverride::Auto:
+        default:
+            return vendorId == kVendorIdQualcomm;
+        }
+    }
+
+    namespace {
+        // MIN/MAX extremum blending: the signature of a depth-bounds accumulation pass
+        // (MC 26.3 OIT writes vec4(-linD, linD, deviceZ, 0) under GL_MAX while writing
+        // depth for its equality chain). MIN/MAX ignore blend factors per the Vulkan spec.
+        //
+        // Deliberately the ONLY shape stripped. A quirk should touch as little unrelated
+        // content as possible, and a trace sweep of every fixture showed the wider
+        // alternatives all cost more than they fix:
+        //   - additive ONE+ONE with a depth write matched zero draws of the 26.3 chain
+        //     (its transmittance/accumulate passes disable depth writes themselves) - the
+        //     only real content it caught was harmless additive glow effects (Create);
+        //   - sorted-transparency "over" blends (SRC_ALPHA-style) are order-dependent,
+        //     drawn once per surface, and rely on their depth writes for occlusion;
+        //   - separate-alpha accumulation over an over-blending color channel has no
+        //     known pairing with a depth-equality chain (color channel only, see tests).
+        // If a future workload pairs another blend shape with an equality chain, widen
+        // this with that evidence in hand rather than pre-emptively.
+        Bool IsAccumulationBlend(const VkPipelineColorBlendAttachmentState& attachment) {
+            return attachment.colorBlendOp == VK_BLEND_OP_MIN ||
+                   attachment.colorBlendOp == VK_BLEND_OP_MAX;
+        }
+    } // namespace
+
+    Bool PipelineFactory::ShouldSuppressDepthWrite(const PipelineCreatePayload& payload) {
+        if (!payload.depthWriteEnable) {
+            return false;
+        }
+        // A shader that assigns gl_FragDepth supplies depth itself rather than taking the
+        // pipeline's interpolated Z, so a driver that varies the vertex position math
+        // between pipelines cannot desynchronize it. (A gl_FragDepth = gl_FragCoord.z
+        // passthrough is the exception that stays exposed; no known content pairs one with
+        // an equality chain, and 26.3's composite is a genuine computed-depth writer.)
+        if (payload.fragmentReplacesDepth) {
+            return false;
+        }
+        for (Uint32 i = 0; i < payload.colorAttachmentCount; ++i) {
+            const VkPipelineColorBlendAttachmentState& attachment = payload.colorBlendAttachments[i];
+            if (attachment.blendEnable != VK_TRUE) {
+                continue;
+            }
+            // All color writes masked: blending is moot (depth-prepass pattern that left
+            // GL_BLEND enabled); stripping the depth write would delete the whole prepass.
+            if (attachment.colorWriteMask == 0) {
+                continue;
+            }
+            // Any attachment qualifies, not just attachment 0: the 26.3 transmittance pass
+            // accumulates into a 2-target MRT and must stay stripped.
+            if (IsAccumulationBlend(attachment)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     PipelineFactory::~PipelineFactory() {
         DestroyAll();
         if (m_pipelineCache != VK_NULL_HANDLE) {
@@ -152,6 +228,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             XXH64_update(m_hashState, &payload.backStencilDepthFailOp, sizeof(payload.backStencilDepthFailOp)));
         XXHASH_VERIFY(
             XXH64_update(m_hashState, &payload.backStencilCompareOp, sizeof(payload.backStencilCompareOp)));
+        XXHASH_VERIFY(
+            XXH64_update(m_hashState, &payload.fragmentReplacesDepth, sizeof(payload.fragmentReplacesDepth)));
         if (payload.colorAttachmentCount > 0) {
             XXHASH_VERIFY(XXH64_update(
                 m_hashState,
@@ -258,6 +336,17 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         for (Uint32 i = 0; i < payload.colorAttachmentCount; ++i) {
             colorAttachments[i] = payload.colorBlendAttachments[i];
         }
+        // Suppress depth writes on accumulation-blended pipelines when the active driver
+        // cannot keep vertex positions invariant across the pipelines of a multi-pass
+        // depth-equality chain (see SetSuppressBlendedDepthWrite). The decision is narrowed
+        // in ShouldSuppressDepthWrite: sorted-transparency "over" blends (vanilla MC water),
+        // gl_FragDepth writers, and masked-out attachments keep their depth writes.
+        // This bakes the decision into the pipeline, which only works because depth write is
+        // static state here - adding VK_DYNAMIC_STATE_DEPTH_WRITE_ENABLE to kDynamicStates
+        // would let the record-time value override it and silently disable the quirk.
+        if (s_suppressBlendedDepthWrite && ShouldSuppressDepthWrite(payload)) {
+            depthStencil.depthWriteEnable = VK_FALSE;
+        }
         VkPipelineColorBlendStateCreateInfo blend{VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO};
         blend.logicOpEnable = payload.logicOpEnable ? VK_TRUE : VK_FALSE;
         blend.logicOp = payload.logicOp;

MobileGL/MG_Backend/DirectVulkan/Renderer/PipelineFactory.h

@@ -49,6 +49,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             VkStencilOp backStencilPassOp = VK_STENCIL_OP_KEEP;
             VkStencilOp backStencilDepthFailOp = VK_STENCIL_OP_KEEP;
             VkCompareOp backStencilCompareOp = VK_COMPARE_OP_ALWAYS;
+            // The fragment module writes gl_FragDepth (SPIR-V DepthReplacing); exempts the
+            // pipeline from the blended depth-write quirk (see ShouldSuppressDepthWrite).
+            Bool fragmentReplacesDepth = false;
             Array<VkPipelineColorBlendAttachmentState, kMaxColorAttachments> colorBlendAttachments{};
             const Vector<VkPipelineShaderStageCreateInfo>* stages = nullptr;
             const VkPipelineVertexInputStateCreateInfo* vertexInputState = nullptr;
@@ -62,6 +65,27 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         VkPipeline GetOrCreatePipeline(const PipelineCreatePayload& payload);
         void DestroyAll();
 
+        // Driver quirk: suppress depth writes on accumulation-blended pipelines. Multi-pass
+        // depth-equality rendering (a blended prepass writes depth that later passes re-test
+        // with an equality-inclusive compare on the re-rasterized geometry) requires
+        // cross-pipeline position invariance that some mobile compilers do not provide, even
+        // with the SPIR-V Invariant decoration; whole primitives then drop out of the later
+        // passes. Only MIN/MAX extremum blends are stripped - the signature of such a
+        // chain's depth-bounds pass (MC 26.3 OIT), and per a fixture-wide trace sweep the
+        // only depth-writing shape the chain actually uses - so every other blend
+        // (sorted-transparency "over" like vanilla MC water, additive glows, ...) keeps
+        // its depth writes. Set at renderer initialization based on the active driver.
+        static void SetSuppressBlendedDepthWrite(Bool enabled);
+        static Bool IsSuppressBlendedDepthWriteEnabled() { return s_suppressBlendedDepthWrite; }
+        // Device gate for the quirk: ForceOn/ForceOff bypass detection, Auto enables it on
+        // the known-affected vendor (Qualcomm).
+        static Bool ShouldSuppressBlendedDepthWriteForDevice(MG_Config::QuirkOverride quirkOverride,
+                                                             Uint32 vendorId);
+        // Pure per-pipeline strip decision (exempts gl_FragDepth writers, masked-out and
+        // non-accumulation blends); combined with the device flag in CreatePipeline. Static
+        // and payload-only so tests can pin the contract without a VkDevice.
+        static Bool ShouldSuppressDepthWrite(const PipelineCreatePayload& payload);
+
     private:
         VkPipeline CreatePipeline(const PipelineCreatePayload& payload) const;
 
@@ -70,5 +94,6 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         VkPipelineCache m_pipelineCache = VK_NULL_HANDLE;
         UnorderedMap<HashType, VkPipeline> m_cache;
         static inline XXH64_state_t* m_hashState = XXH64_createState();
+        static inline Bool s_suppressBlendedDepthWrite = false;
     };
 } // namespace MobileGL::MG_Backend::DirectVulkan

MobileGL/MG_Backend/DirectVulkan/Renderer/ProgramFactory.cpp

@@ -312,34 +312,6 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             return targetEnv;
         }
 
-        // Cheap raw-word scan for an `OpDecorate <id> BuiltIn InstanceIndex` decoration. Used
-        // only to decide whether to warn when shaderDrawParameters is unavailable; a false
-        // negative merely suppresses a diagnostic.
-        Bool SpirvDeclaresInstanceIndexBuiltin(const Vector<Uint>& spirv) {
-            constexpr Uint32 kSpirvMagicNumber = 0x07230203u;
-            constexpr SizeT kHeaderWordCount = 5;
-            if (spirv.size() <= kHeaderWordCount || spirv[0] != kSpirvMagicNumber) {
-                return false;
-            }
-
-            SizeT wordIndex = kHeaderWordCount;
-            while (wordIndex < spirv.size()) {
-                const Uint32 firstWord = spirv[wordIndex];
-                const Uint32 wordCount = firstWord >> 16;
-                const auto opcode = static_cast<spv::Op>(firstWord & 0xffffu);
-                if (wordCount == 0 || wordIndex + wordCount > spirv.size()) {
-                    break;
-                }
-                if (opcode == spv::Op::OpDecorate && wordCount >= 4 &&
-                    static_cast<spv::Decoration>(spirv[wordIndex + 2]) == spv::Decoration::BuiltIn &&
-                    static_cast<spv::BuiltIn>(spirv[wordIndex + 3]) == spv::BuiltIn::InstanceIndex) {
-                    return true;
-                }
-                wordIndex += wordCount;
-            }
-            return false;
-        }
-
         Bool IsInterfaceVariableStaticallyUsed(const Vector<Uint>& spirv, Uint32 spirvId) {
             if (spirv.empty() || spirvId == 0) {
                 return false;
@@ -1122,9 +1094,17 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 for (auto* binding : bindings) {
                     MOBILEGL_ASSERT(binding != nullptr, "ProgramFactory: null descriptor binding reflection record");
                     const auto kind = ReflectDescriptorTypeToBindingKind(binding->descriptor_type);
-                    MOBILEGL_ASSERT(binding->count == 1,
-                                    "ProgramFactory: descriptor arrays are unsupported (name='%s' count=%u)",
-                                    binding->name ? binding->name : "<null>", binding->count);
+                    // UBO instance arrays (uniform Block {...} b[N];) occupy one binding with
+                    // descriptorCount = N; other descriptor arrays stay unsupported and must
+                    // fail program creation cleanly rather than continue with corrupt state.
+                    if (binding->count != 1 && kind != ProgramFactory::DescriptorBindingKind::UniformBufferDynamic) {
+                        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));
+                        destroyReflectModules();
+                        return false;
+                    }
 
                     DescriptorKey key{};
                     key.kind = kind;
@@ -1197,8 +1177,62 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 return TextureTarget::Unknown;
             }
         }
+
+        Bool IsFloatStorageImageUniformType(GLenum uniformType) {
+            switch (uniformType) {
+            case GL_IMAGE_1D:
+            case GL_IMAGE_2D:
+            case GL_IMAGE_3D:
+            case GL_IMAGE_2D_RECT:
+            case GL_IMAGE_CUBE:
+            case GL_IMAGE_BUFFER:
+            case GL_IMAGE_1D_ARRAY:
+            case GL_IMAGE_2D_ARRAY:
+            case GL_IMAGE_CUBE_MAP_ARRAY:
+            case GL_IMAGE_2D_MULTISAMPLE:
+            case GL_IMAGE_2D_MULTISAMPLE_ARRAY:
+                return true;
+            default:
+                return false;
+            }
+        }
     } // namespace
 
+    // A shader that assigns gl_FragDepth (SPIR-V DepthReplacing) supplies depth itself
+    // instead of taking the pipeline's interpolated Z, so a driver that varies the vertex
+    // position math between pipelines cannot desynchronize it; the blended depth-write
+    // quirk therefore leaves it alone (see PipelineFactory::ShouldSuppressDepthWrite).
+    Bool ProgramFactory::ReflectedFragmentReplacesDepth(const SpvReflectShaderModule& reflectModule) {
+        for (Uint32 entryIndex = 0; entryIndex < reflectModule.entry_point_count; ++entryIndex) {
+            const SpvReflectEntryPoint& entryPoint = reflectModule.entry_points[entryIndex];
+            for (Uint32 modeIndex = 0; modeIndex < entryPoint.execution_mode_count; ++modeIndex) {
+                if (entryPoint.execution_modes[modeIndex] == SpvExecutionModeDepthReplacing) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    // glslang's relaxed-Vulkan mode maps GL's gl_InstanceID onto the InstanceIndex builtin.
+    // Without shaderDrawParameters there is no gl_BaseInstance to subtract, so such a shader
+    // cannot be corrected and instanced draws with a non-zero baseInstance misrender; this
+    // detects the case so the user gets one warning instead of silent corruption.
+    Bool ProgramFactory::ReflectedReadsInstanceIndexBuiltin(const SpvReflectShaderModule& reflectModule) {
+        for (Uint32 entryIndex = 0; entryIndex < reflectModule.entry_point_count; ++entryIndex) {
+            const SpvReflectEntryPoint& entryPoint = reflectModule.entry_points[entryIndex];
+            for (Uint32 variableIndex = 0; variableIndex < entryPoint.input_variable_count; ++variableIndex) {
+                const SpvReflectInterfaceVariable* variable = entryPoint.input_variables[variableIndex];
+                if (variable != nullptr &&
+                    (variable->decoration_flags & SPV_REFLECT_DECORATION_BUILT_IN) != 0 &&
+                    variable->built_in == SpvBuiltInInstanceIndex) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
     VkShaderStageFlagBits ProgramFactory::ToVkStage(ShaderStage stage) {
         switch (stage) {
         case ShaderStage::Vertex:
@@ -1218,6 +1252,105 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
     }
 
+    VkFormat ProgramFactory::ConvertSpirvImageFormatToVkFormat(SpvImageFormat format) {
+        switch (format) {
+        case SpvImageFormatUnknown: return VK_FORMAT_UNDEFINED;
+        case SpvImageFormatRgba32f: return VK_FORMAT_R32G32B32A32_SFLOAT;
+        case SpvImageFormatRgba16f: return VK_FORMAT_R16G16B16A16_SFLOAT;
+        case SpvImageFormatR32f: return VK_FORMAT_R32_SFLOAT;
+        case SpvImageFormatRgba8: return VK_FORMAT_R8G8B8A8_UNORM;
+        case SpvImageFormatRgba8Snorm: return VK_FORMAT_R8G8B8A8_SNORM;
+        case SpvImageFormatRg32f: return VK_FORMAT_R32G32_SFLOAT;
+        case SpvImageFormatRg16f: return VK_FORMAT_R16G16_SFLOAT;
+        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;
+        case SpvImageFormatRg16: return VK_FORMAT_R16G16_UNORM;
+        case SpvImageFormatRg8: return VK_FORMAT_R8G8_UNORM;
+        case SpvImageFormatR16: return VK_FORMAT_R16_UNORM;
+        case SpvImageFormatR8: return VK_FORMAT_R8_UNORM;
+        case SpvImageFormatRgba16Snorm: return VK_FORMAT_R16G16B16A16_SNORM;
+        case SpvImageFormatRg16Snorm: return VK_FORMAT_R16G16_SNORM;
+        case SpvImageFormatRg8Snorm: return VK_FORMAT_R8G8_SNORM;
+        case SpvImageFormatR16Snorm: return VK_FORMAT_R16_SNORM;
+        case SpvImageFormatR8Snorm: return VK_FORMAT_R8_SNORM;
+        case SpvImageFormatRgba32i: return VK_FORMAT_R32G32B32A32_SINT;
+        case SpvImageFormatRgba16i: return VK_FORMAT_R16G16B16A16_SINT;
+        case SpvImageFormatRgba8i: return VK_FORMAT_R8G8B8A8_SINT;
+        case SpvImageFormatR32i: return VK_FORMAT_R32_SINT;
+        case SpvImageFormatRg32i: return VK_FORMAT_R32G32_SINT;
+        case SpvImageFormatRg16i: return VK_FORMAT_R16G16_SINT;
+        case SpvImageFormatRg8i: return VK_FORMAT_R8G8_SINT;
+        case SpvImageFormatR16i: return VK_FORMAT_R16_SINT;
+        case SpvImageFormatR8i: return VK_FORMAT_R8_SINT;
+        case SpvImageFormatRgba32ui: return VK_FORMAT_R32G32B32A32_UINT;
+        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 SpvImageFormatRg32ui: return VK_FORMAT_R32G32_UINT;
+        case SpvImageFormatRg16ui: return VK_FORMAT_R16G16_UINT;
+        case SpvImageFormatRg8ui: return VK_FORMAT_R8G8_UINT;
+        case SpvImageFormatR16ui: return VK_FORMAT_R16_UINT;
+        case SpvImageFormatR8ui: return VK_FORMAT_R8_UINT;
+        case SpvImageFormatR64ui: return VK_FORMAT_R64_UINT;
+        case SpvImageFormatR64i: return VK_FORMAT_R64_SINT;
+        case SpvImageFormatMax: return VK_FORMAT_UNDEFINED;
+        }
+        return VK_FORMAT_UNDEFINED;
+    }
+
+    SamplerNumericDomain ProgramFactory::UniformTypeToSamplerNumericDomain(GLenum glType) {
+        switch (glType) {
+        case GL_INT_SAMPLER_1D:
+        case GL_INT_SAMPLER_2D:
+        case GL_INT_SAMPLER_3D:
+        case GL_INT_SAMPLER_CUBE:
+        case GL_INT_SAMPLER_2D_RECT:
+        case GL_INT_SAMPLER_1D_ARRAY:
+        case GL_INT_SAMPLER_2D_ARRAY:
+        case GL_INT_SAMPLER_BUFFER:
+        case GL_INT_SAMPLER_2D_MULTISAMPLE:
+        case GL_INT_SAMPLER_2D_MULTISAMPLE_ARRAY:
+        case GL_INT_SAMPLER_CUBE_MAP_ARRAY:
+            return SamplerNumericDomain::SignedInteger;
+        case GL_UNSIGNED_INT_SAMPLER_1D:
+        case GL_UNSIGNED_INT_SAMPLER_2D:
+        case GL_UNSIGNED_INT_SAMPLER_3D:
+        case GL_UNSIGNED_INT_SAMPLER_CUBE:
+        case GL_UNSIGNED_INT_SAMPLER_2D_RECT:
+        case GL_UNSIGNED_INT_SAMPLER_1D_ARRAY:
+        case GL_UNSIGNED_INT_SAMPLER_2D_ARRAY:
+        case GL_UNSIGNED_INT_SAMPLER_BUFFER:
+        case GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE:
+        case GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE_ARRAY:
+        case GL_UNSIGNED_INT_SAMPLER_CUBE_MAP_ARRAY:
+            return SamplerNumericDomain::UnsignedInteger;
+        case GL_SAMPLER_1D:
+        case GL_SAMPLER_2D:
+        case GL_SAMPLER_3D:
+        case GL_SAMPLER_CUBE:
+        case GL_SAMPLER_2D_RECT:
+        case GL_SAMPLER_1D_ARRAY:
+        case GL_SAMPLER_2D_ARRAY:
+        case GL_SAMPLER_BUFFER:
+        case GL_SAMPLER_2D_MULTISAMPLE:
+        case GL_SAMPLER_2D_MULTISAMPLE_ARRAY:
+        case GL_SAMPLER_CUBE_MAP_ARRAY:
+        case GL_SAMPLER_1D_SHADOW:
+        case GL_SAMPLER_2D_SHADOW:
+        case GL_SAMPLER_CUBE_SHADOW:
+        case GL_SAMPLER_2D_RECT_SHADOW:
+        case GL_SAMPLER_1D_ARRAY_SHADOW:
+        case GL_SAMPLER_2D_ARRAY_SHADOW:
+        case GL_SAMPLER_CUBE_MAP_ARRAY_SHADOW:
+            return SamplerNumericDomain::Float;
+        default:
+            return SamplerNumericDomain::Unknown;
+        }
+    }
+
     ProgramFactory::HashType ProgramFactory::ComputeHash(const MG_State::GLState::ProgramObject& program,
                                                          CompileOptionFlags flags) const {
         XXHASH_VERIFY(XXH64_reset(m_hashState, m_config.CacheVersion));
@@ -1347,6 +1480,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 continue;
             }
 
+            if (!m_shaderDrawParametersEnabled && ReflectedReadsInstanceIndexBuiltin(reflectModule)) {
+                static Bool s_warnedInstanceIndexUnsupported = false;
+                if (!s_warnedInstanceIndexUnsupported) {
+                    s_warnedInstanceIndexUnsupported = true;
+                    MGLOG_W("ProgramFactory: shaderDrawParameters is unavailable; gl_InstanceID cannot be "
+                            "rebased and instanced draws with a non-zero baseInstance may render incorrectly");
+                }
+            }
+
             uint32_t inputCount = 0;
             SpvReflectResult reflectResult = spvReflectEnumerateInputVariables(&reflectModule, &inputCount, nullptr);
             MOBILEGL_ASSERT(reflectResult == SPV_REFLECT_RESULT_SUCCESS,
@@ -1394,6 +1536,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                                 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) {
@@ -1412,9 +1555,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                             "ProgramFactory::ReflectFragmentOutputs: failed to create reflection module (result=%d)",
                             static_cast<Int>(createResult));
             if (createResult != SPV_REFLECT_RESULT_SUCCESS) {
+                // Fail toward the exemption: stripping a genuine gl_FragDepth writer would
+                // corrupt its depth output outright, while wrongly exempting an accumulation
+                // pass merely reverts that one program to the pre-quirk behavior.
+                entry.fragmentReplacesDepth = true;
                 continue;
             }
 
+            entry.fragmentReplacesDepth = ReflectedFragmentReplacesDepth(reflectModule);
+
             uint32_t outputCount = 0;
             SpvReflectResult reflectResult = spvReflectEnumerateOutputVariables(&reflectModule, &outputCount, nullptr);
             MOBILEGL_ASSERT(reflectResult == SPV_REFLECT_RESULT_SUCCESS,
@@ -1465,10 +1614,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         entry.samplerNameByBinding.assign(m_maxBindings, String());
         entry.samplerUniformLocationByBinding.assign(m_maxBindings, -1);
         entry.samplerTextureTargetByBinding.assign(m_maxBindings, TextureTarget::Texture2D);
+        entry.samplerNumericDomainByBinding.assign(m_maxBindings, SamplerNumericDomain::Unknown);
+        entry.storageImageFormatByBinding.assign(m_maxBindings, VK_FORMAT_UNDEFINED);
+        entry.storageImageUsesBindingFormatByBinding.assign(m_maxBindings, false);
         entry.storageBlockNameByBinding.assign(m_maxBindings, String());
         entry.storageBlockIndexByBinding.assign(m_maxBindings, -1);
         entry.globalUboBinding = -1;
         entry.dynamicBindings.clear();
+        entry.bindingDescriptorCounts.assign(m_maxBindings, 1);
+        entry.arrayedUniformBlockIndicesByBinding.clear();
 
         // Use SpvcSession (Reflection mode) to reflect all SPIR-V modules in a single pass per module
         for (const auto& module : spirv) {
@@ -1484,6 +1638,27 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                             "ProgramFactory::ReflectLayout: failed to create reflection module (result=%d)",
                             static_cast<Int>(createReflectResult));
 
+            // Descriptor counts per binding (UBO instance arrays reflect count > 1).
+            UnorderedMap<Uint32, Uint32> descriptorCountByBinding;
+            {
+                uint32_t countProbe = 0;
+                if (spvReflectEnumerateDescriptorBindings(&reflectModule, &countProbe, nullptr) ==
+                        SPV_REFLECT_RESULT_SUCCESS &&
+                    countProbe > 0) {
+                    Vector<SpvReflectDescriptorBinding*> probeBindings(countProbe);
+                    if (spvReflectEnumerateDescriptorBindings(&reflectModule, &countProbe,
+                                                              probeBindings.data()) ==
+                        SPV_REFLECT_RESULT_SUCCESS) {
+                        for (const auto* probeBinding : probeBindings) {
+                            if (probeBinding != nullptr) {
+                                descriptorCountByBinding[probeBinding->binding] =
+                                    std::max<Uint32>(1, probeBinding->count);
+                            }
+                        }
+                    }
+                }
+            }
+
             // Reflect uniform buffers
             auto ubos = session.GetShaderInterface(SPVC_RESOURCE_TYPE_UNIFORM_BUFFER);
             for (const auto& ubo : ubos) {
@@ -1509,9 +1684,69 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     continue;
                 }
 
-                const Uint blockIndex = program.GetUniformBlockIndex(ubo.name.c_str());
-                if (blockIndex == 0xFFFFFFFFu) {
-                    MGLOG_D("ProgramFactory::ReflectLayout: skipping inactive UBO '%s' at binding %u",
+                const auto countIt = descriptorCountByBinding.find(binding);
+                const Uint32 descriptorCount =
+                    countIt != descriptorCountByBinding.end() ? countIt->second : 1u;
+
+                if (descriptorCount <= 1) {
+                    const Uint blockIndex = program.GetUniformBlockIndex(ubo.name.c_str());
+                    if (blockIndex == 0xFFFFFFFFu) {
+                        MGLOG_D("ProgramFactory::ReflectLayout: skipping inactive UBO '%s' at binding %u",
+                                ubo.name.c_str(), binding);
+                        continue;
+                    }
+
+                    MOBILEGL_ASSERT(entry.bindingKinds[binding] == DescriptorBindingKind::None ||
+                                        entry.bindingKinds[binding] == DescriptorBindingKind::UniformBufferDynamic,
+                                    "ProgramFactory::ReflectLayout: descriptor binding %u has conflicting kinds for UBO '%s'",
+                                    binding, ubo.name.c_str());
+                    entry.bindingKinds[binding] = DescriptorBindingKind::UniformBufferDynamic;
+                    MOBILEGL_ASSERT(entry.globalUboBinding != static_cast<Int>(binding),
+                                    "ProgramFactory::ReflectLayout: regular UBO '%s' collides with global UBO binding %u",
+                                    ubo.name.c_str(), binding);
+                    MOBILEGL_ASSERT(entry.uniformBlockIndexByBinding[binding] < 0 ||
+                                        entry.uniformBlockIndexByBinding[binding] == static_cast<Int>(blockIndex),
+                                    "ProgramFactory::ReflectLayout: descriptor binding %u maps to conflicting UBO blocks (%d vs %u)",
+                                    binding, entry.uniformBlockIndexByBinding[binding], blockIndex);
+                    entry.uniformBlockIndexByBinding[binding] = static_cast<Int>(blockIndex);
+                    continue;
+                }
+
+                // UBO instance array: one binding, descriptorCount elements. GL exposes each
+                // element as its own active block named "Name[i]"; map every element to its
+                // GL block index so the descriptor write can gather per-element buffer ranges.
+                if (descriptorCount > m_maxBindings) {
+                    MGLOG_E("ProgramFactory::ReflectLayout: UBO array '%s' count %u exceeds maxBindings=%u; "
+                            "leaving binding %u unmapped",
+                            ubo.name.c_str(), descriptorCount, m_maxBindings, binding);
+                    continue;
+                }
+                Vector<Int> elementBlockIndices;
+                elementBlockIndices.reserve(descriptorCount);
+                for (Uint32 element = 0; element < descriptorCount; ++element) {
+                    String elementName = ubo.name + "[" + std::to_string(element) + "]";
+                    Uint elementBlockIndex = program.GetUniformBlockIndex(elementName.c_str());
+                    if (elementBlockIndex == 0xFFFFFFFFu && element == 0) {
+                        // Some frontends report the first element under the bare block name.
+                        elementBlockIndex = program.GetUniformBlockIndex(ubo.name.c_str());
+                    }
+                    if (elementBlockIndex == 0xFFFFFFFFu) {
+                        // Degrade rather than corrupt: reuse element 0's block if we have one,
+                        // otherwise give up on the binding (same observable behavior as an
+                        // inactive block: wrong values, but no crash).
+                        MGLOG_E("ProgramFactory::ReflectLayout: UBO array '%s' element %u has no active "
+                                "GL uniform block",
+                                ubo.name.c_str(), element);
+                        if (!elementBlockIndices.empty()) {
+                            elementBlockIndex = static_cast<Uint>(elementBlockIndices.front());
+                        } else {
+                            break;
+                        }
+                    }
+                    elementBlockIndices.push_back(static_cast<Int>(elementBlockIndex));
+                }
+                if (elementBlockIndices.size() != descriptorCount) {
+                    MGLOG_E("ProgramFactory::ReflectLayout: skipping unresolved UBO array '%s' at binding %u",
                             ubo.name.c_str(), binding);
                     continue;
                 }
@@ -1521,14 +1756,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                 "ProgramFactory::ReflectLayout: descriptor binding %u has conflicting kinds for UBO '%s'",
                                 binding, ubo.name.c_str());
                 entry.bindingKinds[binding] = DescriptorBindingKind::UniformBufferDynamic;
-                MOBILEGL_ASSERT(entry.globalUboBinding != static_cast<Int>(binding),
-                                "ProgramFactory::ReflectLayout: regular UBO '%s' collides with global UBO binding %u",
-                                ubo.name.c_str(), binding);
-                MOBILEGL_ASSERT(entry.uniformBlockIndexByBinding[binding] < 0 ||
-                                    entry.uniformBlockIndexByBinding[binding] == static_cast<Int>(blockIndex),
-                                "ProgramFactory::ReflectLayout: descriptor binding %u maps to conflicting UBO blocks (%d vs %u)",
-                                binding, entry.uniformBlockIndexByBinding[binding], blockIndex);
-                entry.uniformBlockIndexByBinding[binding] = static_cast<Int>(blockIndex);
+                entry.bindingDescriptorCounts[binding] = static_cast<Uint16>(descriptorCount);
+                entry.uniformBlockIndexByBinding[binding] = elementBlockIndices[0];
+                entry.arrayedUniformBlockIndicesByBinding[binding] = Move(elementBlockIndices);
             }
 
             // Reflect sampled images, storage images, samplerBuffer uniforms, and SSBOs.
@@ -1592,10 +1822,54 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     continue;
                 }
 
-                const TextureTarget target = UniformTypeToTextureTarget(program.GetUniformType(static_cast<Uint>(location)));
+                const GLenum uniformType = program.GetUniformType(static_cast<Uint>(location));
+
+                if (descriptorKind == DescriptorBindingKind::StorageImage) {
+                    const VkFormat reflectedFormat =
+                        ConvertSpirvImageFormatToVkFormat(sampler->image.image_format);
+                    VkFormat& existingFormat = entry.storageImageFormatByBinding[binding];
+                    MOBILEGL_ASSERT(existingFormat == VK_FORMAT_UNDEFINED ||
+                                        reflectedFormat == VK_FORMAT_UNDEFINED ||
+                                        existingFormat == reflectedFormat,
+                                    "ProgramFactory::ReflectLayout: storage image binding %u ('%s') has "
+                                    "conflicting reflected formats (%d vs %d)",
+                                    binding, uniformName.c_str(), static_cast<Int>(existingFormat),
+                                    static_cast<Int>(reflectedFormat));
+                    if (existingFormat == VK_FORMAT_UNDEFINED) {
+                        existingFormat = reflectedFormat;
+                    }
+                    if (m_unformattedFloatStorageImagesEnabled &&
+                        existingFormat == VK_FORMAT_UNDEFINED &&
+                        IsFloatStorageImageUniformType(uniformType)) {
+                        entry.storageImageUsesBindingFormatByBinding[binding] = true;
+                    } else if (reflectedFormat != VK_FORMAT_UNDEFINED) {
+                        // A typed declaration in any stage wins for the entire binding. This is
+                        // required when another stage reaches the same image through an atomic
+                        // path and therefore could not be made formatless.
+                        entry.storageImageUsesBindingFormatByBinding[binding] = false;
+                    }
+                }
+
+                const TextureTarget target = UniformTypeToTextureTarget(uniformType);
                 MOBILEGL_ASSERT(target != TextureTarget::Unknown,
                                 "ProgramFactory::ReflectLayout: failed to resolve texture target for '%s'",
                                 uniformName.c_str());
+                if (descriptorKind == DescriptorBindingKind::CombinedImageSampler) {
+                    const SamplerNumericDomain numericDomain = UniformTypeToSamplerNumericDomain(uniformType);
+                    MOBILEGL_ASSERT(numericDomain != SamplerNumericDomain::Unknown,
+                                    "ProgramFactory::ReflectLayout: failed to resolve sampler numeric domain "
+                                    "for '%s' (uniformType=0x%x)",
+                                    uniformName.c_str(), uniformType);
+                    MOBILEGL_ASSERT(entry.samplerNumericDomainByBinding[binding] ==
+                                            SamplerNumericDomain::Unknown ||
+                                        entry.samplerNumericDomainByBinding[binding] == numericDomain,
+                                    "ProgramFactory::ReflectLayout: sampler binding %u ('%s') has conflicting "
+                                    "numeric domains (%d vs %d)",
+                                    binding, uniformName.c_str(),
+                                    static_cast<Int>(entry.samplerNumericDomainByBinding[binding]),
+                                    static_cast<Int>(numericDomain));
+                    entry.samplerNumericDomainByBinding[binding] = numericDomain;
+                }
                 MOBILEGL_ASSERT(entry.samplerUniformLocationByBinding[binding] < 0 || location < 0 ||
                                     entry.samplerUniformLocationByBinding[binding] == location,
                                 "ProgramFactory::ReflectLayout: texture binding %u maps to conflicting uniform locations (%d vs %d)",
@@ -1631,7 +1905,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
             VkDescriptorSetLayoutBinding layoutBinding{};
             layoutBinding.binding = binding;
-            layoutBinding.descriptorCount = 1;
+            layoutBinding.descriptorCount = entry.bindingDescriptorCounts[binding];
             layoutBinding.stageFlags = VK_SHADER_STAGE_ALL;
             layoutBinding.pImmutableSamplers = nullptr;
             if (kind == DescriptorBindingKind::UniformBufferDynamic) {
@@ -1643,6 +1917,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 layoutBinding.descriptorType = VK_DESCRIPTOR_TYPE_STORAGE_BUFFER;
             } else if (kind == DescriptorBindingKind::StorageImage) {
                 layoutBinding.descriptorType = VK_DESCRIPTOR_TYPE_STORAGE_IMAGE;
+                entry.hasStorageImages = true;
             } else {
                 layoutBinding.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
             }
@@ -1697,28 +1972,60 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 moduleSpirvs[i] = spv;
             }
 
+            // GL apps depend on cross-program position invariance for multi-pass equality
+            // depth tests (MC 26.3's OIT re-draws the cloud geometry with GEQUAL against the
+            // depth its own first pass wrote); decorate Position outputs Invariant so
+            // per-pipeline compilers cannot vary the position math between passes.
+            {
+                Vector<Uint> invariantSpirv;
+                if (MG_Util::ShaderTranspiler::ShaderCompiler::DecoratePositionInvariantForVulkan(
+                        moduleSpirvs[i], invariantSpirv)) {
+                    moduleSpirvs[i] = std::move(invariantSpirv);
+                } else {
+                    // The pass round-trips through SPIRV-Tools IR, so an unparseable module
+                    // fails open and keeps the undecorated words - which silently reinstates
+                    // the multi-pass invariance bug rather than breaking anything loudly.
+                    MGLOG_E("ProgramFactory: position-invariant decoration failed for program %u; "
+                            "keeping the original module - multi-pass depth-equality chains "
+                            "(e.g. MC 26.3 OIT clouds) may drop primitives on this device",
+                            program.GetExternalIndex());
+                }
+            }
+
             // glslang's relaxed-Vulkan mode aliases GL's zero-based gl_InstanceID to Vulkan's
             // gl_InstanceIndex, which wrongly includes the draw's baseInstance. Rebase vertex-stage
             // loads to (InstanceIndex - BaseInstance) so shaders observe GL semantics. Reflection
             // below runs on the rebased words so the added BaseInstance builtin stays consistent.
-            if (shaders[i] && shaders[i]->GetShaderStage() == ShaderStage::Vertex) {
-                if (m_shaderDrawParametersEnabled) {
-                    Vector<Uint> rebasedSpirv;
-                    if (MG_Util::ShaderTranspiler::ShaderCompiler::RebaseInstanceIndexForVulkan(moduleSpirvs[i],
-                                                                                               rebasedSpirv)) {
-                        moduleSpirvs[i] = std::move(rebasedSpirv);
-                    } else {
-                        MGLOG_E("ProgramFactory: failed to rebase gl_InstanceID for program %u; "
-                                "instanced draws with a non-zero baseInstance may render incorrectly",
-                                program.GetExternalIndex());
-                    }
-                } else if (SpirvDeclaresInstanceIndexBuiltin(moduleSpirvs[i])) {
-                    static Bool s_warnedInstanceIndexUnsupported = false;
-                    if (!s_warnedInstanceIndexUnsupported) {
-                        s_warnedInstanceIndexUnsupported = true;
-                        MGLOG_W("ProgramFactory: shaderDrawParameters is unavailable; gl_InstanceID cannot be "
-                                "rebased and instanced draws with a non-zero baseInstance may render incorrectly");
-                    }
+            // 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) {
+                Vector<Uint> rebasedSpirv;
+                if (MG_Util::ShaderTranspiler::ShaderCompiler::RebaseInstanceIndexForVulkan(moduleSpirvs[i],
+                                                                                            rebasedSpirv)) {
+                    moduleSpirvs[i] = std::move(rebasedSpirv);
+                } else {
+                    MGLOG_E("ProgramFactory: failed to rebase gl_InstanceID for program %u; "
+                            "instanced draws with a non-zero baseInstance may render incorrectly",
+                            program.GetExternalIndex());
+                }
+            }
+
+            // When Vulkan can legally access storage images without a statically declared
+            // format, let GL's glBindImageTexture format select the runtime image view. This
+            // provides desktop-driver-compatible behavior for packs such as iterationRP, whose
+            // float image qualifier can disagree with the bound render-target format. Integer
+            // storage images remain formatted so r32ui/r32i bit-reinterpretation paths keep the
+            // exact descriptor format required by their shader operations.
+            if (m_unformattedFloatStorageImagesEnabled) {
+                Vector<Uint> unformattedSpirv;
+                if (MG_Util::ShaderTranspiler::ShaderCompiler::UseUnformattedFloatStorageImagesForVulkan(
+                        moduleSpirvs[i], unformattedSpirv)) {
+                    moduleSpirvs[i] = std::move(unformattedSpirv);
+                } else {
+                    MGLOG_E("ProgramFactory: failed to make float storage images unformatted for program %u",
+                            program.GetExternalIndex());
                 }
             }
         }

MobileGL/MG_Backend/DirectVulkan/Renderer/ProgramFactory.h

@@ -14,8 +14,16 @@
 #include "MG_State/GLState/TextureState/TextureEnum.h"
 
 #include <Includes.h>
+#include <spirv_reflect.h>
 
 namespace MobileGL::MG_Backend::DirectVulkan {
+    enum class SamplerNumericDomain : Uint8 {
+        Unknown = 0,
+        Float,
+        SignedInteger,
+        UnsignedInteger,
+    };
+
     class ProgramFactory {
     public:
         enum class DescriptorBindingKind : Uint8 {
@@ -51,11 +59,23 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             Vector<DescriptorBindingKind> bindingKinds;
             Vector<Uint32> dynamicBindings;
             Vector<Int> uniformBlockIndexByBinding;
+            // Descriptor count per binding (1 except for UBO instance arrays, which occupy one
+            // binding with descriptorCount = N).
+            Vector<Uint16> bindingDescriptorCounts;
+            // Per-element GL uniform block indices for arrayed UBO bindings (count > 1);
+            // element 0 of a non-arrayed binding stays in uniformBlockIndexByBinding.
+            UnorderedMap<Uint32, Vector<Int>> arrayedUniformBlockIndicesByBinding;
             Vector<String> samplerNameByBinding;
             Vector<Int> samplerUniformLocationByBinding;
             Vector<TextureTarget> samplerTextureTargetByBinding;
+            Vector<SamplerNumericDomain> samplerNumericDomainByBinding;
+            Vector<VkFormat> storageImageFormatByBinding;
+            Vector<Bool> storageImageUsesBindingFormatByBinding;
             Vector<String> storageBlockNameByBinding;
             Vector<Int> storageBlockIndexByBinding;
+            // Set once during ReflectLayout so the per-draw path can skip the whole
+            // storage-image preparation for the overwhelming majority of programs.
+            Bool hasStorageImages = false;
             Int globalUboBinding = -1;
             Uint32 activeVertexInputLocationMask = 0;
             Array<GLenum, kMaxVertexInputLocations> vertexInputTypes{};
@@ -64,6 +84,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             ShaderStage rasterizationProducerStage = ShaderStage::Unknown;
             Uint32 producerOutputComponentCount = 0;
             Uint32 fragmentInputComponentCount = 0;
+            // The fragment module declares the DepthReplacing execution mode (writes
+            // gl_FragDepth); shader-computed depth is immune to the cross-pipeline
+            // position-invariance quirk (see PipelineFactory::ShouldSuppressDepthWrite).
+            Bool fragmentReplacesDepth = false;
 
             static inline VkDevice s_device = VK_NULL_HANDLE;
 
@@ -79,11 +103,18 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 bindingKinds = std::move(other.bindingKinds);
                 dynamicBindings = std::move(other.dynamicBindings);
                 uniformBlockIndexByBinding = std::move(other.uniformBlockIndexByBinding);
+                bindingDescriptorCounts = std::move(other.bindingDescriptorCounts);
+                arrayedUniformBlockIndicesByBinding = std::move(other.arrayedUniformBlockIndicesByBinding);
                 samplerNameByBinding = std::move(other.samplerNameByBinding);
                 samplerUniformLocationByBinding = std::move(other.samplerUniformLocationByBinding);
                 samplerTextureTargetByBinding = std::move(other.samplerTextureTargetByBinding);
+                samplerNumericDomainByBinding = std::move(other.samplerNumericDomainByBinding);
+                storageImageFormatByBinding = std::move(other.storageImageFormatByBinding);
+                storageImageUsesBindingFormatByBinding =
+                    std::move(other.storageImageUsesBindingFormatByBinding);
                 storageBlockNameByBinding = std::move(other.storageBlockNameByBinding);
                 storageBlockIndexByBinding = std::move(other.storageBlockIndexByBinding);
+                hasStorageImages = other.hasStorageImages;
                 globalUboBinding = other.globalUboBinding;
                 activeVertexInputLocationMask = other.activeVertexInputLocationMask;
                 vertexInputTypes = other.vertexInputTypes;
@@ -92,15 +123,18 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 rasterizationProducerStage = other.rasterizationProducerStage;
                 producerOutputComponentCount = other.producerOutputComponentCount;
                 fragmentInputComponentCount = other.fragmentInputComponentCount;
+                fragmentReplacesDepth = other.fragmentReplacesDepth;
                 other.hash = 0;
                 other.descriptorSetLayout = VK_NULL_HANDLE;
                 other.pipelineLayout = VK_NULL_HANDLE;
+                other.hasStorageImages = false;
                 other.globalUboBinding = -1;
                 other.activeVertexInputLocationMask = 0;
                 other.activeFragmentOutputLocationMask = 0;
                 other.rasterizationProducerStage = ShaderStage::Unknown;
                 other.producerOutputComponentCount = 0;
                 other.fragmentInputComponentCount = 0;
+                other.fragmentReplacesDepth = false;
             }
             VkProgramObject& operator=(VkProgramObject&& other) noexcept {
                 if (this == &other) {
@@ -115,11 +149,18 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 bindingKinds = std::move(other.bindingKinds);
                 dynamicBindings = std::move(other.dynamicBindings);
                 uniformBlockIndexByBinding = std::move(other.uniformBlockIndexByBinding);
+                bindingDescriptorCounts = std::move(other.bindingDescriptorCounts);
+                arrayedUniformBlockIndicesByBinding = std::move(other.arrayedUniformBlockIndicesByBinding);
                 samplerNameByBinding = std::move(other.samplerNameByBinding);
                 samplerUniformLocationByBinding = std::move(other.samplerUniformLocationByBinding);
                 samplerTextureTargetByBinding = std::move(other.samplerTextureTargetByBinding);
+                samplerNumericDomainByBinding = std::move(other.samplerNumericDomainByBinding);
+                storageImageFormatByBinding = std::move(other.storageImageFormatByBinding);
+                storageImageUsesBindingFormatByBinding =
+                    std::move(other.storageImageUsesBindingFormatByBinding);
                 storageBlockNameByBinding = std::move(other.storageBlockNameByBinding);
                 storageBlockIndexByBinding = std::move(other.storageBlockIndexByBinding);
+                hasStorageImages = other.hasStorageImages;
                 globalUboBinding = other.globalUboBinding;
                 activeVertexInputLocationMask = other.activeVertexInputLocationMask;
                 vertexInputTypes = other.vertexInputTypes;
@@ -128,15 +169,18 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 rasterizationProducerStage = other.rasterizationProducerStage;
                 producerOutputComponentCount = other.producerOutputComponentCount;
                 fragmentInputComponentCount = other.fragmentInputComponentCount;
+                fragmentReplacesDepth = other.fragmentReplacesDepth;
                 other.hash = 0;
                 other.descriptorSetLayout = VK_NULL_HANDLE;
                 other.pipelineLayout = VK_NULL_HANDLE;
+                other.hasStorageImages = false;
                 other.globalUboBinding = -1;
                 other.activeVertexInputLocationMask = 0;
                 other.activeFragmentOutputLocationMask = 0;
                 other.rasterizationProducerStage = ShaderStage::Unknown;
                 other.producerOutputComponentCount = 0;
                 other.fragmentInputComponentCount = 0;
+                other.fragmentReplacesDepth = false;
                 return *this;
             }
 
@@ -167,9 +211,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         };
 
         explicit ProgramFactory(VkDevice device, const VulkanRendererConfig& config, Uint32 maxBindings = 16,
-                                Bool shaderDrawParametersEnabled = false)
+                                Bool shaderDrawParametersEnabled = false,
+                                Bool unformattedFloatStorageImagesEnabled = false)
             : m_device(device), m_maxBindings(maxBindings), m_config(config),
-              m_shaderDrawParametersEnabled(shaderDrawParametersEnabled) {
+              m_shaderDrawParametersEnabled(shaderDrawParametersEnabled),
+              m_unformattedFloatStorageImagesEnabled(unformattedFloatStorageImagesEnabled) {
             VkProgramObject::s_device = device;
         }
         ~ProgramFactory() = default;
@@ -180,6 +226,16 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             const MG_State::GLState::ProgramObject& program, CompileOptionFlags flags);
 
         static VkShaderStageFlagBits ToVkStage(ShaderStage stage);
+        static VkFormat ConvertSpirvImageFormatToVkFormat(SpvImageFormat format);
+        static SamplerNumericDomain UniformTypeToSamplerNumericDomain(GLenum glType);
+        // True when any entry point declares the DepthReplacing execution mode, i.e. the
+        // shader assigns gl_FragDepth. Exposed so the blended depth-write quirk's exemption
+        // can be pinned by tests. A false negative loses the exemption, so such a shader is
+        // stripped conservatively and forfeits its depth write.
+        static Bool ReflectedFragmentReplacesDepth(const SpvReflectShaderModule& reflectModule);
+        // True when an entry point reads the InstanceIndex builtin. Only gates a diagnostic:
+        // without shaderDrawParameters such a shader cannot have gl_InstanceID rebased.
+        static Bool ReflectedReadsInstanceIndexBuiltin(const SpvReflectShaderModule& reflectModule);
 
     private:
         struct ProgramLookupCache {
@@ -206,6 +262,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // True when the device enabled shaderDrawParameters; gates the InstanceIndex rebase pass
         // (which needs the DrawParameters capability / gl_BaseInstance builtin).
         Bool m_shaderDrawParametersEnabled = false;
+        // True only when the logical device enabled both
+        // shaderStorageImageReadWithoutFormat and shaderStorageImageWriteWithoutFormat.
+        Bool m_unformattedFloatStorageImagesEnabled = false;
         mutable ProgramLookupCache m_lastLookup;
         static inline XXH64_state_t* m_hashState = XXH64_createState();
     };

MobileGL/MG_Backend/DirectVulkan/Renderer/UniformManager.cpp

@@ -13,6 +13,7 @@
 #include "MG_State/GLState/ProgramState/ProgramObject.h"
 #include "MG_State/GLState/TextureState/TextureObject2D.h"
 #include "MG_State/GLState/TextureState/TextureObjectBuffer.h"
+#include "MG_Util/Converters/GLToMG/TextureEnumConverter.h"
 #include "MG_Util/Converters/MGToStr/FramebufferEnumConverter.h"
 #include "MG_Util/Converters/MGToVk/TextureEnumConverter.h"
 #include "MG_Util/Metrics/TextureMetrics.h"
@@ -78,6 +79,16 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return uniformUnit >= 0 ? uniformUnit : 0;
     }
 
+    VkFormat UniformManager::ResolveStorageImageViewFormat(VkFormat reflectedFormat, GLenum bindingFormat,
+                                                           VkFormat resourceFormat, Bool useBindingFormat) {
+        if (useBindingFormat) {
+            const TextureInternalFormat bindingInternalFormat =
+                MG_Util::ConvertGLEnumToTextureInternalFormat(bindingFormat);
+            return MG_Util::ConvertTextureInternalFormatToVkEnum(bindingInternalFormat);
+        }
+        return reflectedFormat != VK_FORMAT_UNDEFINED ? reflectedFormat : resourceFormat;
+    }
+
     Bool UniformManager::Initialize(VkDevice device, VkBufferManager* bufferManager,
                                              ProgramFactory* programFactory,
                                              VkDeviceSize minUniformBufferOffsetAlignment, Uint32 frameCount,
@@ -276,6 +287,55 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                             "ResolveSamplerDescriptor: invalid sampled image layout=%d for textureId=%d, binding=%u",
                             static_cast<Int>(resource->layout), texture->GetExternalIndex(), binding);
         }
+
+        MOBILEGL_ASSERT(binding < programObj.samplerNumericDomainByBinding.size(),
+                        "ResolveSamplerDescriptor: sampler numeric-domain binding %u out of range", binding);
+        const SamplerNumericDomain numericDomain = programObj.samplerNumericDomainByBinding[binding];
+        // Vulkan forbids linear filtering and anisotropy for integer sampled-image formats.
+        // Some desktop GL shader packs deliberately bit-read a mutable float texture through a
+        // usampler and still leave the texture's ordinary linear parameters in place; texelFetch
+        // ignores filtering, so a nearest VkSampler preserves the operation while keeping the
+        // descriptor valid.
+        const Bool forceNearestFiltering = numericDomain == SamplerNumericDomain::SignedInteger ||
+                                           numericDomain == SamplerNumericDomain::UnsignedInteger;
+        SamplerResolveMemo* viewFormatMemo =
+            binding < m_samplerResolveMemo.size() ? &m_samplerResolveMemo[binding] : nullptr;
+        VkFormat sampledViewFormat;
+        if (viewFormatMemo != nullptr && viewFormatMemo->viewFormatValid &&
+            viewFormatMemo->viewFormatSource == resource->format &&
+            viewFormatMemo->viewFormatDomain == numericDomain) {
+            sampledViewFormat = viewFormatMemo->viewFormat;
+        } else {
+            sampledViewFormat =
+                VkTextureManager::ResolveSampledImageViewFormat(resource->format, numericDomain);
+            if (viewFormatMemo != nullptr) {
+                viewFormatMemo->viewFormatSource = resource->format;
+                viewFormatMemo->viewFormatDomain = numericDomain;
+                viewFormatMemo->viewFormat = sampledViewFormat;
+                viewFormatMemo->viewFormatValid = true;
+            }
+        }
+        if (sampledViewFormat == VK_FORMAT_UNDEFINED) {
+            MGLOG_E("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));
+            return false;
+        }
+        // No reinterpretation requested: bind the depth-or-color aspect view the sync above
+        // already produced instead of re-entering GetOrCreateSampledImageView's sync path.
+        const VkImageView sampledImageView =
+            sampledViewFormat == resource->format
+                ? resource->sampledView
+                : m_textureManager->GetOrCreateSampledImageView(*texture, sampledViewFormat);
+        if (sampledImageView == VK_NULL_HANDLE) {
+            MGLOG_E("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),
+                    static_cast<Int>(numericDomain));
+            return false;
+        }
         // Skip GetOrCreateSampler's per-draw key hash + map lookup when this binding's
         // sampler object and texture (both by lifetime id + version) are unchanged from the
         // last draw that resolved it: the resulting sampler key, and therefore the VkSampler
@@ -291,23 +351,27 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             const Uint64 textureLifetimeId = texture->GetLifetimeId();
             const Uint16 textureParamsVersion = texture->GetTextureParamsVersion();
             if (memo.valid && memo.samplerLifetimeId == samplerLifetimeId && memo.samplerVersion == samplerVersion &&
-                memo.textureLifetimeId == textureLifetimeId && memo.textureParamsVersion == textureParamsVersion) {
+                memo.textureLifetimeId == textureLifetimeId && memo.textureParamsVersion == textureParamsVersion &&
+                memo.forceNearestFiltering == forceNearestFiltering) {
                 resolvedSampler = memo.sampler;
             } else {
-                resolvedSampler = m_samplerManager->GetOrCreateSampler(*samplerToUse, *texture);
+                resolvedSampler =
+                    m_samplerManager->GetOrCreateSampler(*samplerToUse, *texture, forceNearestFiltering);
                 memo.samplerLifetimeId = samplerLifetimeId;
                 memo.samplerVersion = samplerVersion;
                 memo.textureLifetimeId = textureLifetimeId;
                 memo.textureParamsVersion = textureParamsVersion;
+                memo.forceNearestFiltering = forceNearestFiltering;
                 memo.sampler = resolvedSampler;
                 memo.valid = true;
             }
         } else {
-            resolvedSampler = m_samplerManager->GetOrCreateSampler(*samplerToUse, *texture);
+            resolvedSampler =
+                m_samplerManager->GetOrCreateSampler(*samplerToUse, *texture, forceNearestFiltering);
         }
         outImageInfo = {
             .sampler = resolvedSampler,
-            .imageView = resource->sampledView != VK_NULL_HANDLE ? resource->sampledView : resource->fullView,
+            .imageView = sampledImageView,
             .imageLayout = resource->layout,
         };
         return outImageInfo.sampler != VK_NULL_HANDLE;
@@ -360,6 +424,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         auto& textureUnit = MG_State::pGLContext->GetTextureUnitObject(unit);
         const TextureTarget preferredTarget = programObj.samplerTextureTargetByBinding[binding];
         outTexture = textureUnit.GetBindingSlot(preferredTarget).GetBoundObject();
+        // The slot always holds at least the target's default texture (name 0). While that
+        // default has no image it is unsampleable; report it as "unbound" so callers keep
+        // taking their fallback paths instead of trying to sync a storage-less texture.
+        if (MG_State::GLState::IsUndefinedDefaultTexture(outTexture.get())) {
+            outTexture.reset();
+        }
 
         return true;
     }
@@ -380,7 +450,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const TextureTarget preferredTarget = programObj.samplerTextureTargetByBinding[binding];
         // GetBoundObject() returns the SharedPtr by const ref; .get() reads the pointer without
         // touching the refcount (no atomic inc/dec per binding per draw).
-        return textureUnit.GetBindingSlot(preferredTarget).GetBoundObject().get();
+        MG_State::GLState::ITextureObject* texture =
+            textureUnit.GetBindingSlot(preferredTarget).GetBoundObject().get();
+        // The slot always holds at least the target's default texture (name 0). While that
+        // default has no image it is unsampleable; report it as "unbound" so the caller
+        // substitutes its fallback texture exactly like it did for the old null slot.
+        if (MG_State::GLState::IsUndefinedDefaultTexture(texture)) {
+            return nullptr;
+        }
+        return texture;
     }
 
     Bool UniformManager::ResolveTexelBufferDescriptor(const MG_State::GLState::ProgramObject& program,
@@ -558,9 +636,32 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
 
         const Uint32 mipLevel = static_cast<Uint32>(std::max<GLint>(0, imageBinding.Level));
-        VkImageView view = m_textureManager->GetOrCreateViewAtMipLevel(*imageBinding.Texture, mipLevel);
+        MOBILEGL_ASSERT(binding < programObj.storageImageFormatByBinding.size(),
+                        "ResolveStorageImageDescriptor: storage image format binding %u out of range", binding);
+        MOBILEGL_ASSERT(binding < programObj.storageImageUsesBindingFormatByBinding.size(),
+                        "ResolveStorageImageDescriptor: storage image format policy binding %u out of range",
+                        binding);
+        const VkFormat reflectedFormat = programObj.storageImageFormatByBinding[binding];
+        const Bool useBindingFormat = programObj.storageImageUsesBindingFormatByBinding[binding];
+        const VkFormat viewFormat = ResolveStorageImageViewFormat(
+            reflectedFormat, imageBinding.Format, resource->format, useBindingFormat);
+        if (viewFormat == VK_FORMAT_UNDEFINED) {
+            MGLOG_E("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");
+            return false;
+        }
+        const VkImageView view = m_textureManager->GetOrCreateStorageImageView(
+            *imageBinding.Texture, mipLevel, viewFormat, imageBinding.Layered != GL_FALSE, imageBinding.Layer);
         if (view == VK_NULL_HANDLE) {
-            view = resource->fullView;
+            MGLOG_E("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),
+                    static_cast<Int>(viewFormat),
+                    useBindingFormat ? "true" : "false");
+            return false;
         }
         outImageInfo.sampler = VK_NULL_HANDLE;
         outImageInfo.imageView = view;
@@ -599,7 +700,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
             MG_State::GLState::ITextureObject* texture = ResolveSamplerTextureRaw(program, programObj, binding);
             if (!texture) {
-                continue;
+                // ResolveSamplerDescriptor will substitute the fallback texture for this binding;
+                // include it in the sampled set so the pre-render-pass sync/transition pass covers
+                // its first use instead of leaving that work to happen inside an active pass.
+                const TextureTarget preferredTarget = programObj.samplerTextureTargetByBinding[binding];
+                if (preferredTarget != TextureTarget::Texture2D &&
+                    preferredTarget != TextureTarget::TextureRectangle) {
+                    continue;
+                }
+                texture = GetFallbackTexture(preferredTarget).get();
             }
 
             auto found = std::find(outTextures.begin(), outTextures.end(), texture);
@@ -610,9 +719,53 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return true;
     }
 
+    Bool UniformManager::CollectStorageImageTextures(
+        const MG_State::GLState::ProgramObject& program,
+        const ProgramFactory::VkProgramObject& programObj,
+        Vector<MG_State::GLState::ITextureObject*>& outTextures) const {
+        outTextures.clear();
+        MOBILEGL_ASSERT(MG_State::pGLContext != nullptr,
+                        "CollectStorageImageTextures: GL context is null");
+
+        const Uint32 bindingCount =
+            std::min<Uint32>(m_maxBindings, static_cast<Uint32>(programObj.bindingKinds.size()));
+        for (Uint32 binding = 0; binding < bindingCount; ++binding) {
+            if (programObj.bindingKinds[binding] != ProgramFactory::DescriptorBindingKind::StorageImage) {
+                continue;
+            }
+            if (binding >= programObj.samplerUniformLocationByBinding.size()) {
+                MGLOG_E("CollectStorageImageTextures: binding %u has no uniform-location mapping", binding);
+                return false;
+            }
+
+            const Int location = programObj.samplerUniformLocationByBinding[binding];
+            if (location < 0) {
+                MGLOG_E("CollectStorageImageTextures: binding %u has no image uniform location", binding);
+                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",
+                        imageUnit, binding);
+                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",
+                        imageUnit, binding);
+                return false;
+            }
+            if (std::find(outTextures.begin(), outTextures.end(), texture) == outTextures.end()) {
+                outTextures.push_back(texture);
+            }
+        }
+        return true;
+    }
+
     Bool UniformManager::ResolveUniformBufferPayload(const MG_State::GLState::ProgramObject& program,
                                                      const ProgramFactory::VkProgramObject& programObj, Uint32 binding,
-                                                     UboBindResult& out) const {
+                                                     Uint32 arrayElement, UboBindResult& out) const {
         const void* outData = nullptr;
         VkDeviceSize outSize = 0;
 
@@ -638,7 +791,19 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         MOBILEGL_ASSERT(binding < programObj.uniformBlockIndexByBinding.size(),
                         "ResolveUniformBufferPayload: UBO mapping binding %u out of range", binding);
-        const Int blockIndex = programObj.uniformBlockIndexByBinding[binding];
+        Int blockIndex = programObj.uniformBlockIndexByBinding[binding];
+        if (arrayElement > 0) {
+            const auto arrayIt = programObj.arrayedUniformBlockIndicesByBinding.find(binding);
+            const Bool elementValid = arrayIt != programObj.arrayedUniformBlockIndicesByBinding.end() &&
+                                      arrayElement < arrayIt->second.size();
+            MOBILEGL_ASSERT(elementValid,
+                            "ResolveUniformBufferPayload: UBO binding %u has no array element %u", binding,
+                            arrayElement);
+            if (!elementValid) {
+                return false;
+            }
+            blockIndex = arrayIt->second[arrayElement];
+        }
         MOBILEGL_ASSERT(blockIndex >= 0,
                         "ResolveUniformBufferPayload: no uniform block mapped to descriptor binding %u", binding);
 
@@ -885,11 +1050,17 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         imageInfos.clear();
         texelBufferViews.clear();
         dynamicOffsets.clear();
+        // Arrayed UBO bindings contribute extra buffer infos and dynamic offsets; reserve for
+        // the worst case so the pBufferInfo pointers taken below never dangle on reallocation.
+        Uint32 uboArrayExtra = 0;
+        for (const auto& arrayEntry : programObj.arrayedUniformBlockIndicesByBinding) {
+            uboArrayExtra += static_cast<Uint32>(arrayEntry.second.size()) - 1u;
+        }
         writes.reserve(m_maxBindings);
-        bufferInfos.reserve(m_maxBindings);
+        bufferInfos.reserve(m_maxBindings + uboArrayExtra);
         imageInfos.reserve(m_maxBindings);
         texelBufferViews.reserve(m_maxBindings);
-        dynamicOffsets.reserve(programObj.dynamicBindings.size());
+        dynamicOffsets.reserve(programObj.dynamicBindings.size() + uboArrayExtra);
 
         const Uint32 bindingCount =
             std::min<Uint32>(m_maxBindings, static_cast<Uint32>(programObj.bindingKinds.size()));
@@ -907,40 +1078,51 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             write.descriptorCount = 1;
 
             if (kind == ProgramFactory::DescriptorBindingKind::UniformBufferDynamic) {
-                UboBindResult ubo{};
-                const Bool hasPayload = ResolveUniformBufferPayload(program, programObj, binding, ubo);
-                MOBILEGL_ASSERT(hasPayload && ubo.payload != nullptr && ubo.payloadSize > 0,
-                                "UniformDescriptorBinder::BindProgramUniformBuffers failed: missing UBO payload on binding %u",
-                                binding);
+                const Uint32 descriptorCount =
+                    binding < programObj.bindingDescriptorCounts.size()
+                        ? std::max<Uint32>(1, programObj.bindingDescriptorCounts[binding])
+                        : 1u;
+                const SizeT firstBufferInfoIndex = bufferInfos.size();
+                for (Uint32 element = 0; element < descriptorCount; ++element) {
+                    UboBindResult ubo{};
+                    const Bool hasPayload =
+                        ResolveUniformBufferPayload(program, programObj, binding, element, ubo);
+                    MOBILEGL_ASSERT(hasPayload && ubo.payload != nullptr && ubo.payloadSize > 0,
+                                    "UniformDescriptorBinder::BindProgramUniformBuffers failed: missing UBO payload on binding %u element %u",
+                                    binding, element);
 
-                VkDescriptorBufferInfo bufferInfo{};
-                // Keep offset 0 (sub-range selected via the dynamic offset) so the hashed bufferInfo
-                // is stable across draws and the descriptor-set reuse cache keeps hitting.
-                bufferInfo.offset = 0;
-                Uint32 dynOffset;
-                if (ubo.directBindable) {
-                    // Zero-copy: bind the app's resident VkBuffer directly, no per-draw memcpy.
-                    bufferInfo.buffer = ubo.buffer;
-                    bufferInfo.range = ubo.range;
-                    dynOffset = static_cast<Uint32>(ubo.dynamicOffset);
-                } else {
-                    BufferSlice slice{};
-                    if (!m_bufferManager->UploadTransient(BufferKind::Uniform, frameIndex, ubo.payload,
-                                                          ubo.payloadSize, m_minDynamicOffsetAlignment, slice)) {
-                        MOBILEGL_ASSERT(false, "UniformDescriptorBinder::BindProgramUniformBuffers failed: UBO upload failed on binding %u",
-                                binding);
-                        return false;
+                    VkDescriptorBufferInfo bufferInfo{};
+                    // Keep offset 0 (sub-range selected via the dynamic offset) so the hashed bufferInfo
+                    // is stable across draws and the descriptor-set reuse cache keeps hitting.
+                    bufferInfo.offset = 0;
+                    Uint32 dynOffset;
+                    if (ubo.directBindable) {
+                        // Zero-copy: bind the app's resident VkBuffer directly, no per-draw memcpy.
+                        bufferInfo.buffer = ubo.buffer;
+                        bufferInfo.range = ubo.range;
+                        dynOffset = static_cast<Uint32>(ubo.dynamicOffset);
+                    } else {
+                        BufferSlice slice{};
+                        if (!m_bufferManager->UploadTransient(BufferKind::Uniform, frameIndex, ubo.payload,
+                                                              ubo.payloadSize, m_minDynamicOffsetAlignment, slice)) {
+                            MOBILEGL_ASSERT(false, "UniformDescriptorBinder::BindProgramUniformBuffers failed: UBO upload failed on binding %u element %u",
+                                    binding, element);
+                            return false;
+                        }
+                        bufferInfo.buffer = slice.buffer;
+                        bufferInfo.range = ubo.payloadSize;
+                        dynOffset = static_cast<Uint32>(slice.offset);
                     }
-                    bufferInfo.buffer = slice.buffer;
-                    bufferInfo.range = ubo.payloadSize;
-                    dynOffset = static_cast<Uint32>(slice.offset);
+                    bufferInfos.push_back(bufferInfo);
+                    // Dynamic offsets are consumed in binding order, then array element order,
+                    // matching Vulkan's dynamic-offset consumption rules.
+                    dynamicOffsets.push_back(dynOffset);
                 }
-                bufferInfos.push_back(bufferInfo);
 
                 write.descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC;
-                write.pBufferInfo = &bufferInfos.back();
+                write.descriptorCount = descriptorCount;
+                write.pBufferInfo = &bufferInfos[firstBufferInfoIndex];
                 writes.push_back(write);
-                dynamicOffsets.push_back(dynOffset);
             } else if (kind == ProgramFactory::DescriptorBindingKind::UniformTexelBuffer) {
                 VkBufferView bufferView = VK_NULL_HANDLE;
                 if (!ResolveTexelBufferDescriptor(program, programObj, binding, frameIndex, bufferView) ||

MobileGL/MG_Backend/DirectVulkan/Renderer/UniformManager.h

@@ -42,6 +42,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Bool CollectSampledTextures(const MG_State::GLState::ProgramObject& program,
                                     const ProgramFactory::VkProgramObject& programObj,
                                     Vector<MG_State::GLState::ITextureObject*>& outTextures);
+        Bool CollectStorageImageTextures(const MG_State::GLState::ProgramObject& program,
+                                         const ProgramFactory::VkProgramObject& programObj,
+                                         Vector<MG_State::GLState::ITextureObject*>& outTextures) const;
         Bool BindProgramUniformBuffers(VkCommandBuffer commandBuffer,
                                        const MG_State::GLState::ProgramObject& program,
                                        const ProgramFactory::VkProgramObject& programObj,
@@ -49,6 +52,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                        VkPipelineBindPoint bindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS,
                                        const SamplerBindingOverride* samplerBindingOverride = nullptr);
 
+        // Pure format-policy helper kept public for host regression tests. Formatted storage
+        // images use their shader qualifier; transformed float images use glBindImageTexture's
+        // format and never silently fall back to the backing image format.
+        static VkFormat ResolveStorageImageViewFormat(VkFormat reflectedFormat, GLenum bindingFormat,
+                                                      VkFormat resourceFormat, Bool useBindingFormat);
+
     private:
         struct DescriptorPoolBucket {
             VkDescriptorPool handle = VK_NULL_HANDLE;
@@ -107,7 +116,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         };
         Bool ResolveUniformBufferPayload(const MG_State::GLState::ProgramObject& program,
                                          const ProgramFactory::VkProgramObject& programObj, Uint32 binding,
-                                         UboBindResult& out) const;
+                                         Uint32 arrayElement, UboBindResult& out) const;
         Bool CreateDescriptorPool(Uint32 maxSets, VkDescriptorPool& outPool) const;
         Bool GrowFrameDescriptorPool(FrameResources& frame, Uint32 frameIndex);
         VkResult AllocateDescriptorSetsFromActivePool(
@@ -165,9 +174,16 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             VkSampler sampler = VK_NULL_HANDLE;
             Uint16 samplerVersion = 0;
             Uint16 textureParamsVersion = 0;
+            Bool forceNearestFiltering = false;
             Bool valid = false;
+            // ResolveSampledImageViewFormat is pure in (image format, numeric domain), but a
+            // domain mismatch walks a ~184-entry format table. Memo the resolution per binding
+            // so a reinterpreted sampler pays that scan once, not once per draw.
+            VkFormat viewFormatSource = VK_FORMAT_UNDEFINED;
+            SamplerNumericDomain viewFormatDomain = SamplerNumericDomain::Unknown;
+            VkFormat viewFormat = VK_FORMAT_UNDEFINED;
+            Bool viewFormatValid = false;
         };
         mutable Vector<SamplerResolveMemo> m_samplerResolveMemo;
     };
 } // namespace MobileGL::MG_Backend::DirectVulkan
-

MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.cpp

@@ -66,6 +66,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Vector<SizeT> bindingBaseOffsets;
         Vector<Uint32> bindingAttributeLocations;
         Vector<Bool> bindingUsesClientMemory;
+        Vector<VertexStreamConversion> bindingConversions;
         Uint32 unsupportedAttribMask = 0;
 
         for (Uint32 location = 0; location < MG_State::GLState::VertexArrayObject::MAX_VERTEX_ATTRIBS; ++location) {
@@ -74,8 +75,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 continue;
             }
 
-            const auto vkFormat = ToVkVertexFormat(attr.Type, attr.Size, attr.Normalized, attr.IsInteger, attr.IsBgra);
-            if (vkFormat == VK_FORMAT_UNDEFINED) {
+            const VkFormat sourceVkFormat =
+                ToVkVertexFormat(attr.Type, attr.Size, attr.Normalized, attr.IsInteger, attr.IsBgra);
+            if (sourceVkFormat == VK_FORMAT_UNDEFINED) {
                 MGLOG_E("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);
@@ -83,6 +85,33 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 continue;
             }
 
+            VkFormat vkFormat = sourceVkFormat;
+            VertexStreamConversion conversion = VertexStreamConversion::None;
+            if (!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 "
+                                "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),
+                                MG_Util::ConvertDataTypeToString(attr.Type).c_str(), attr.Size,
+                                attr.Normalized ? "true" : "false", attr.IsInteger ? "true" : "false");
+                    }
+                }
+
+                if (conversion == VertexStreamConversion::None) {
+                    MGLOG_E("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);
+                    unsupportedAttribMask |= (1u << location);
+                    continue;
+                }
+            }
+
             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 "
@@ -92,8 +121,33 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 continue;
             }
 
-            const Uint32 stride =
+            const Uint32 sourceStride =
                 attr.Stride > 0 ? static_cast<Uint32>(attr.Stride) : static_cast<Uint32>(attribByteSize);
+            const Bool packedAttribute = attr.Type == DataType::Int2101010Rev ||
+                                         attr.Type == DataType::Uint2101010Rev;
+            const SizeT requiredAlignment = packedAttribute ? attribByteSize : GetComponentSize(attr.Type);
+            // For a client-memory array attr.Offset holds the raw client pointer, and the
+            // draw path re-uploads the data to a 16-aligned transient slice with attribute
+            // offset 0, so only the stride can violate Vulkan's fetch alignment there.
+            const Bool clientMemoryAttribute = attr.Buffer == nullptr;
+            if (conversion == VertexStreamConversion::None && requiredAlignment > 1 &&
+                ((sourceStride % requiredAlignment) != 0 ||
+                 (!clientMemoryAttribute && (attr.Offset % requiredAlignment) != 0))) {
+                // GL accepts arbitrary byte strides and offsets. Core Vulkan vertex fetches do not
+                // 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 "
+                        "(offset=%zu stride=%u required=%zu); using a tightly packed stream",
+                        location, attr.Offset, sourceStride, requiredAlignment);
+            }
+
+            Uint32 stride = sourceStride;
+            if (conversion == VertexStreamConversion::Repack) {
+                stride = static_cast<Uint32>(attribByteSize);
+            } else if (conversion == VertexStreamConversion::ScaledIntegerToFloat32) {
+                stride = static_cast<Uint32>(attr.Size * static_cast<Int>(sizeof(Float)));
+            }
             const VkVertexInputRate inputRate =
                 (attr.Divisor == 0) ? VK_VERTEX_INPUT_RATE_VERTEX : VK_VERTEX_INPUT_RATE_INSTANCE;
 
@@ -103,6 +157,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             bindingBaseOffsets.push_back(attr.Buffer ? attr.Offset : 0);
             bindingAttributeLocations.push_back(location);
             bindingUsesClientMemory.push_back(attr.Buffer == nullptr);
+            bindingConversions.push_back(conversion);
             builder.AddBinding(binding, stride, inputRate);
             builder.AddAttribute(location, binding, vkFormat, 0);
         }
@@ -117,6 +172,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         entry.bindingBaseOffsets = std::move(bindingBaseOffsets);
         entry.bindingAttributeLocations = std::move(bindingAttributeLocations);
         entry.bindingUsesClientMemory = std::move(bindingUsesClientMemory);
+        entry.bindingConversions = std::move(bindingConversions);
         entry.unsupportedAttribMask = unsupportedAttribMask;
         entry.state = state;
         entry.state.pVertexBindingDescriptions = entry.bindings.empty() ? nullptr : entry.bindings.data();
@@ -282,4 +338,47 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const SizeT componentSize = GetComponentSize(type);
         return componentSize == 0 ? 0 : componentSize * static_cast<SizeT>(size);
     }
+
+    Bool VertexInputStateFactory::IsScaledIntegerVertexFormat(VkFormat format) {
+        switch (format) {
+        case VK_FORMAT_R8_USCALED:
+        case VK_FORMAT_R8_SSCALED:
+        case VK_FORMAT_R8G8_USCALED:
+        case VK_FORMAT_R8G8_SSCALED:
+        case VK_FORMAT_R8G8B8_USCALED:
+        case VK_FORMAT_R8G8B8_SSCALED:
+        case VK_FORMAT_R8G8B8A8_USCALED:
+        case VK_FORMAT_R8G8B8A8_SSCALED:
+        case VK_FORMAT_R16_USCALED:
+        case VK_FORMAT_R16_SSCALED:
+        case VK_FORMAT_R16G16_USCALED:
+        case VK_FORMAT_R16G16_SSCALED:
+        case VK_FORMAT_R16G16B16_USCALED:
+        case VK_FORMAT_R16G16B16_SSCALED:
+        case VK_FORMAT_R16G16B16A16_USCALED:
+        case VK_FORMAT_R16G16B16A16_SSCALED:
+            return true;
+        default:
+            return false;
+        }
+    }
+
+    VkFormat VertexInputStateFactory::ToFloat32VertexFormat(Int componentCount) {
+        switch (componentCount) {
+        case 1: return VK_FORMAT_R32_SFLOAT;
+        case 2: return VK_FORMAT_R32G32_SFLOAT;
+        case 3: return VK_FORMAT_R32G32B32_SFLOAT;
+        case 4: return VK_FORMAT_R32G32B32A32_SFLOAT;
+        default: return VK_FORMAT_UNDEFINED;
+        }
+    }
+
+    Bool VertexInputStateFactory::SupportsVertexBufferFormat(VkFormat format) const {
+        if (m_physicalDevice == VK_NULL_HANDLE || format == VK_FORMAT_UNDEFINED) {
+            return false;
+        }
+        VkFormatProperties properties{};
+        vkGetPhysicalDeviceFormatProperties(m_physicalDevice, format, &properties);
+        return (properties.bufferFeatures & VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT) != 0;
+    }
 } // namespace MobileGL::MG_Backend::DirectVulkan

MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.h

@@ -19,6 +19,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     public:
         using HashType = Uint64;
 
+        enum class VertexStreamConversion : Uint8 {
+            None = 0,
+            Repack,
+            ScaledIntegerToFloat32,
+        };
+
         struct BackendVertexInputState {
             HashType hash = 0;
             Vector<VkVertexInputBindingDescription> bindings;
@@ -27,6 +33,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             Vector<SizeT> bindingBaseOffsets;
             Vector<Uint32> bindingAttributeLocations;
             Vector<Bool> bindingUsesClientMemory;
+            Vector<VertexStreamConversion> bindingConversions;
             // Locations whose array is ENABLED but whose GL format has no VkFormat mapping. They are
             // absent from `attributes`, so without this mask the draw path cannot tell them apart from
             // a genuinely disabled array and would silently feed the shader the current attribute value.
@@ -36,8 +43,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             };
         };
 
-        explicit VertexInputStateFactory(const VulkanRendererConfig& config):
-            m_config(config) {}
+        VertexInputStateFactory(const VulkanRendererConfig& config, VkPhysicalDevice physicalDevice):
+            m_config(config), m_physicalDevice(physicalDevice) {}
         ~VertexInputStateFactory() = default;
         VertexInputStateFactory(const VertexInputStateFactory&) = delete;
 
@@ -56,8 +63,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
     private:
         static VkFormat ToVkVertexFormat(DataType type, Int size, Bool normalized, Bool isInteger, Bool isBgra = false);
+        static Bool IsScaledIntegerVertexFormat(VkFormat format);
+        static VkFormat ToFloat32VertexFormat(Int componentCount);
+        Bool SupportsVertexBufferFormat(VkFormat format) const;
 
         const VulkanRendererConfig& m_config;
+        VkPhysicalDevice m_physicalDevice = VK_NULL_HANDLE;
         UnorderedMap<HashType, BackendVertexInputState> m_cache;
         static inline XXH64_state_t* m_hashState = XXH64_createState();
     };

MobileGL/MG_Backend/DirectVulkan/Renderer/VkBufferManager.cpp

@@ -197,16 +197,20 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return static_cast<VkBufferResource*>(bufferObject.GetBackendResource().get());
     }
 
-    SharedPtr<VkBufferResource> VkBufferManager::GetOrCreateResource(
+    VkBufferResource* VkBufferManager::GetOrCreateResource(
         const SharedPtr<MG_State::GLState::BufferObject>& bufferObject) {
-        auto existing = std::static_pointer_cast<VkBufferResource>(bufferObject->GetBackendResource());
+        // Return by raw pointer: the resource is owned for its whole lifetime by the BufferObject's
+        // backend-resource SharedPtr (already set, or set below), so callers that only dereference
+        // it avoid a static_pointer_cast + SharedPtr refcount inc/dec on every per-draw buffer bind.
+        const auto& existing = bufferObject->GetBackendResource();
         if (existing) {
-            return existing;
+            return static_cast<VkBufferResource*>(existing.get());
         }
         auto resource = MakeShared<VkBufferResource>();
+        VkBufferResource* raw = resource.get();
         bufferObject->SetBackendResource(resource);
         TrackLiveResource(resource);
-        return resource;
+        return raw;
     }
 
     void VkBufferManager::TrackLiveResource(const SharedPtr<VkBufferResource>& resource) {

MobileGL/MG_Backend/DirectVulkan/Renderer/VkBufferManager.h

@@ -124,7 +124,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     private:
         Bool InitializeTransientArenas();
         static VkBufferUsageFlags GetVkBufferUsage(BufferKind kind);
-        SharedPtr<VkBufferResource> GetOrCreateResource(const SharedPtr<MG_State::GLState::BufferObject>& bufferObject);
+        VkBufferResource* GetOrCreateResource(const SharedPtr<MG_State::GLState::BufferObject>& bufferObject);
         static VkBufferResource* ResourceOf(MG_State::GLState::BufferObject& bufferObject);
         Bool CreateResidentStorage(VkBufferResource& resource, VkDeviceSize size, VkBufferUsageFlags usage,
                                    VkMemoryPropertyFlags requiredFlags = 0);

MobileGL/MG_Backend/DirectVulkan/Renderer/VkBufferObject.cpp

@@ -157,6 +157,25 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return true;
     }
 
+    Bool VkBufferObject::Invalidate(VkDeviceSize size, VkDeviceSize offset) {
+        MOBILEGL_ASSERT(IsValid(), "VkBufferObject::Invalidate called on invalid buffer");
+        MOBILEGL_ASSERT(IsMapped(), "VkBufferObject::Invalidate requires mapped memory");
+        MOBILEGL_ASSERT(offset <= m_size, "VkBufferObject::Invalidate offset out of range");
+
+        const VkDeviceSize resolvedSize = size == VK_WHOLE_SIZE ? m_size - offset : size;
+        MOBILEGL_ASSERT(offset + resolvedSize <= m_size, "VkBufferObject::Invalidate range out of bounds");
+        if (resolvedSize == 0) {
+            return true;
+        }
+
+        const VkResult result = vmaInvalidateAllocation(m_allocator, m_allocation, offset, resolvedSize);
+        if (result != VK_SUCCESS) {
+            MGLOG_E("VkBufferObject::Invalidate failed: vmaInvalidateAllocation returned %d", result);
+            return false;
+        }
+        return true;
+    }
+
     BufferSlice VkBufferObject::GetSlice(VkDeviceSize offset, VkDeviceSize size) const {
         MOBILEGL_ASSERT(offset <= m_size, "VkBufferObject::GetSlice offset out of range");
         const VkDeviceSize resolvedSize = (size == VK_WHOLE_SIZE) ? (m_size - offset) : size;

MobileGL/MG_Backend/DirectVulkan/Renderer/VkBufferObject.h

@@ -44,6 +44,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         void* Map();
         void Unmap();
         Bool Upload(const void* data, VkDeviceSize size, VkDeviceSize offset = 0);
+        Bool Invalidate(VkDeviceSize size = VK_WHOLE_SIZE, VkDeviceSize offset = 0);
 
         VkBuffer GetHandle() const { return m_buffer; }
         VkDeviceSize GetSize() const { return m_size; }

MobileGL/MG_Backend/DirectVulkan/Renderer/VkRenderPassManager.cpp

@@ -251,11 +251,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         const auto internalFormat = renderbuffer->GetInternalFormat();
         const VkFormat format = MG_Util::ConvertTextureInternalFormatToVkEnum(internalFormat);
         const VkImageAspectFlags aspect = ResolveImageAspectMaskForFormat(format);
-        if ((aspect & VK_IMAGE_ASPECT_COLOR_BIT) != 0) {
-            MGLOG_E("GetOrCreateRenderbufferResource: color renderbuffer %u is not supported by DirectVulkan render passes yet",
-                    renderbuffer->GetExternalIndex());
-            return nullptr;
-        }
+        // Renderbuffers are never sampled (GL has no way to bind one to a sampler), so the
+        // usage set is attachment + transfer: transfer covers readback (vkCmdCopyImageToBuffer),
+        // BlitFramebuffer, CopyTexImage sources, and out-of-render-pass clear materialization.
+        const VkImageUsageFlags imageUsage =
+            ((aspect & VK_IMAGE_ASPECT_COLOR_BIT) != 0 ? VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT
+                                                       : VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT) |
+            VK_IMAGE_USAGE_TRANSFER_SRC_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
 
         auto& resource = m_renderbufferResources[renderbuffer.get()];
         const Bool needsCreate =
@@ -285,7 +287,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         imageInfo.format = format;
         imageInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
         imageInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
-        imageInfo.usage = VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
+        imageInfo.usage = imageUsage;
         imageInfo.samples = sampleCount;
         imageInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
 
@@ -386,6 +388,18 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     void VkRenderPassManager::QueueRenderbufferClear(
         GLbitfield mask, const ClearFramebufferPayload& clearPayload,
         const MG_State::GLState::FramebufferObject& drawFbo) {
+        if ((mask & GL_COLOR_BUFFER_BIT) != 0) {
+            // Color renderbuffer draw buffers take the framebuffer-level clear too; texture
+            // attachments are skipped by the per-attachment overload's IsRenderbuffer guard.
+            for (const auto attachmentType : drawFbo.GetDrawBuffers()) {
+                if (attachmentType == FramebufferAttachmentType::None) {
+                    continue;
+                }
+                QueueRenderbufferClear(
+                    ClearAttachmentPayload{.mask = GL_COLOR_BUFFER_BIT, .color = clearPayload.color},
+                    drawFbo.GetAttachment(attachmentType));
+            }
+        }
         if ((mask & GL_DEPTH_BUFFER_BIT) != 0) {
             QueueRenderbufferClear(
                 ClearAttachmentPayload{.mask = GL_DEPTH_BUFFER_BIT, .depth = clearPayload.depth},
@@ -602,6 +616,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             m_rpFastRenderPassHash == activeRenderPass->hash && !hasPendingClearOnFramebuffer()) {
             auto activeIt = m_renderPasses.find(activeRenderPass->hash);
             if (activeIt != m_renderPasses.end()) {
+                activeIt->second.lastUsedFrame = m_frameCounter;
                 return activeIt->second;
             }
         }
@@ -623,12 +638,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             m_rpFastTexEpoch = m_textureManager.GetTextureImageEpoch();
             m_rpFastRbEpoch = m_renderbufferImageEpoch;
             m_rpFastRenderPassHash = activeRenderPass->hash;
+            activeIt->second.lastUsedFrame = m_frameCounter;
             return activeIt->second;
         }
         auto hash = ComputeHash(fbo, swapchainImageIndex, true);
         auto it = m_renderPasses.find(hash);
-        if (it != m_renderPasses.end())
+        if (it != m_renderPasses.end()) {
+            it->second.lastUsedFrame = m_frameCounter;
             return it->second;
+        }
 
         Bool isDefaultFbo = fbo.IsDefaultFramebuffer();
         // Color attachment
@@ -678,6 +696,83 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // assuming default FBO has the right param
         for (Uint32 i = 0; i < colorAttachmentSlotCount; ++i) {
             auto drawbuf = drawbufs[i];
+
+            // Renderbuffer color attachments mirror the texture path below, with the
+            // resource (image/view/format/layout) coming from the render-pass manager's
+            // renderbuffer store instead of the texture manager.
+            if (drawbuf != FramebufferAttachmentType::None && !isDefaultFbo) {
+                const auto& rbAtt = fbo.GetAttachment(drawbuf);
+                if (rbAtt.IsRenderbuffer() && rbAtt.IsComplete()) {
+                    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 "
+                                "renderbuffer %u; using VK_ATTACHMENT_UNUSED",
+                                i, fbo.GetExternalIndex(), renderbuffer->GetExternalIndex());
+                        continue;
+                    }
+
+                    const Uint32 rbAttachmentIndex = static_cast<Uint32>(attachmentDescriptions.size());
+                    attachmentDescriptions.emplace_back();
+                    VkAttachmentDescription& rbDesc = attachmentDescriptions.back();
+
+                    ClearAttachmentPayload rbClearPayload{};
+                    Bool rbHasClear = GetPendingRenderbufferClear(renderbuffer.get(), rbClearPayload) &&
+                                      (rbClearPayload.mask & GL_COLOR_BUFFER_BIT) != 0;
+                    if (rbHasClear &&
+                        MG_Util::GetBaseInternalFormatComponentCount(renderbuffer->GetInternalFormat()) == 3) {
+                        // RGB renderbuffers are backed by an RGBA image; the missing alpha reads as 1.
+                        rbClearPayload.color =
+                            FloatVec4(rbClearPayload.color.x(), rbClearPayload.color.y(),
+                                      rbClearPayload.color.z(), 1.0f);
+                    }
+
+                    const VkImageLayout trackedRbLayout = rbResource->layout;
+                    rbDesc.flags = 0;
+                    rbDesc.format = rbResource->format;
+                    rbDesc.samples = rbResource->sampleCount;
+                    rbDesc.loadOp = rbHasClear ? VK_ATTACHMENT_LOAD_OP_CLEAR :
+                                    (trackedRbLayout == VK_IMAGE_LAYOUT_UNDEFINED ? VK_ATTACHMENT_LOAD_OP_DONT_CARE
+                                                                                  : VK_ATTACHMENT_LOAD_OP_LOAD);
+                    rbDesc.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
+                    rbDesc.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
+                    rbDesc.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
+                    rbDesc.initialLayout = (rbHasClear || trackedRbLayout == VK_IMAGE_LAYOUT_UNDEFINED) ?
+                        VK_IMAGE_LAYOUT_UNDEFINED : trackedRbLayout;
+                    rbDesc.finalLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
+                    adoptRenderPassSampleCount(rbResource->sampleCount, "color",
+                                               static_cast<Int>(renderbuffer->GetExternalIndex()));
+
+                    if (rbHasClear) {
+                        pendingClearAttachments.emplace_back(PendingClearAttachmentInfo {
+                            .attachmentIndex = rbAttachmentIndex,
+                            .colorAttachmentSlot = i,
+                            .renderbuffer = renderbuffer.get(),
+                            .hasInlinePayload = true,
+                            .inlinePayload = rbClearPayload,
+                        });
+                    }
+
+                    if (width == 0)
+                        width = static_cast<Int>(rbResource->extent.width);
+                    if (height == 0)
+                        height = static_cast<Int>(rbResource->extent.height);
+
+                    trackedAttachmentLayouts.emplace_back(TrackedAttachmentLayoutInfo {
+                        .target = TrackedAttachmentTarget::Renderbuffer,
+                        .renderbuffer = renderbuffer,
+                        .finalLayout = rbDesc.finalLayout,
+                    });
+                    textureResources.emplace_back(nullptr);
+                    attachmentViews.emplace_back(rbResource->view);
+                    MOBILEGL_ASSERT(attachmentViews.back() != VK_NULL_HANDLE,
+                                    "GetOrCreateRenderPass: renderbuffer view missing at color attachment %d", i);
+
+                    colorAttachmentRefs[i].attachment = rbAttachmentIndex;
+                    continue;
+                }
+            }
+
             auto* texture = ResolveCompleteColorAttachmentTexture(fbo, drawbuf, i);
             if (texture == nullptr)
                 continue;
@@ -696,6 +791,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 case TextureTarget::Texture2D:
                 case TextureTarget::Texture2DArray:
                 case TextureTarget::Texture2DMultisample:
+                case TextureTarget::Texture2DMultisampleArray:
+                case TextureTarget::Texture3D:
+                case TextureTarget::TextureCubeMap:
+                case TextureTarget::TextureCubeMapArray:
                 case TextureTarget::TextureRectangle: {
                     desc.flags = 0;
                     desc.format = isDefaultFbo ?
@@ -718,6 +817,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     if (hasClear) {
                         pendingClearAttachments.emplace_back(PendingClearAttachmentInfo {
                             .attachmentIndex = attachmentIndex,
+                            .colorAttachmentSlot = i,
                             .key = VkClearManager::MakePendingClearKey(att)
                         });
                     }
@@ -974,6 +1074,52 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         subpassDesc.preserveAttachmentCount = 0;
         subpassDesc.pPreserveAttachments = nullptr;
 
+        // External subpass dependencies. Without them there is NO execution/memory
+        // dependency between consecutive render passes (or a pass and a transfer)
+        // touching the same attachments when the image layout does not change — the
+        // layout-transition helper no-ops on identical layouts and no other barrier
+        // exists. Tile-based GPUs then race tile loads against the previous pass's
+        // stores (multi-pass FBO chains like MC 26.3's OIT flicker on Adreno).
+        // Conservative both-ways dependencies: prior writes (attachment output,
+        // depth/stencil, transfer, shader) are made visible to this pass's loads,
+        // and this pass's attachment writes to subsequent sampling/transfer/loads.
+        VkSubpassDependency subpassDependencies[2];
+        subpassDependencies[0] = {};
+        subpassDependencies[0].srcSubpass = VK_SUBPASS_EXTERNAL;
+        subpassDependencies[0].dstSubpass = 0;
+        subpassDependencies[0].srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT |
+                                              VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT |
+                                              VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT | VK_PIPELINE_STAGE_TRANSFER_BIT;
+        subpassDependencies[0].srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT |
+                                               VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT |
+                                               VK_ACCESS_SHADER_WRITE_BIT | VK_ACCESS_TRANSFER_WRITE_BIT;
+        subpassDependencies[0].dstStageMask = VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT |
+                                              VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT |
+                                              VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT |
+                                              VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
+        subpassDependencies[0].dstAccessMask =
+            VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT |
+            VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT | VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT |
+            VK_ACCESS_SHADER_READ_BIT;
+        subpassDependencies[0].dependencyFlags = 0;
+        subpassDependencies[1] = {};
+        subpassDependencies[1].srcSubpass = 0;
+        subpassDependencies[1].dstSubpass = VK_SUBPASS_EXTERNAL;
+        subpassDependencies[1].srcStageMask =
+            VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT | VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT;
+        subpassDependencies[1].srcAccessMask =
+            VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT | VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT;
+        subpassDependencies[1].dstStageMask = VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT |
+                                              VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT |
+                                              VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT |
+                                              VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT |
+                                              VK_PIPELINE_STAGE_TRANSFER_BIT;
+        subpassDependencies[1].dstAccessMask =
+            VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT |
+            VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT | VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT |
+            VK_ACCESS_SHADER_READ_BIT | VK_ACCESS_TRANSFER_READ_BIT | VK_ACCESS_TRANSFER_WRITE_BIT;
+        subpassDependencies[1].dependencyFlags = 0;
+
         // Render Pass
         VkRenderPassCreateInfo renderPassCreateInfo;
         renderPassCreateInfo.sType = VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO;
@@ -983,8 +1129,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         renderPassCreateInfo.pAttachments = attachmentDescriptions.data();
         renderPassCreateInfo.subpassCount = 1;
         renderPassCreateInfo.pSubpasses = &subpassDesc;
-        renderPassCreateInfo.dependencyCount = 0;
-        renderPassCreateInfo.pDependencies = nullptr;
+        renderPassCreateInfo.dependencyCount = 2;
+        renderPassCreateInfo.pDependencies = subpassDependencies;
 
         VkRenderPass renderPass = VK_NULL_HANDLE;
         VK_VERIFY(vkCreateRenderPass(m_device, &renderPassCreateInfo, nullptr, &renderPass));
@@ -1015,7 +1161,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             hasDepthStencilAttachment,
             renderPassSampleCount,
             extent,
-            static_cast<Int>(framebufferLayers) };
+            framebufferLayers };
         MGLOG_D("VkRenderPassManager::GetOrCreateRenderPass: hash=0x%llx compatibilityHash=0x%llx attachmentCount=%u colorAttachmentCount=%u samples=%d extent=%dx%d",
                 static_cast<unsigned long long>(hash),
                 static_cast<unsigned long long>(compatibilityHash),
@@ -1025,9 +1171,36 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 extent.x(),
                 extent.y());
         auto [insertedIt, _] = m_renderPasses.emplace(hash, Move(renderPassEntry));
+        insertedIt->second.lastUsedFrame = m_frameCounter;
         return insertedIt->second;
     }
 
+    void VkRenderPassManager::OnPresent() {
+        ++m_frameCounter;
+
+        // Sweep occasionally; evict entries whose last use is far past every
+        // in-flight frame so their VkRenderPass/VkFramebuffer can be destroyed
+        // safely (RenderPassEntry's destructor releases the handles).
+        constexpr Uint64 kSweepInterval = 256;
+        constexpr Uint64 kRetireAgeFrames = 1024;
+        if ((m_frameCounter % kSweepInterval) != 0) {
+            return;
+        }
+
+        const Uint64 activeHash = s_hasActiveRenderPass ? s_activeRenderPass.hash : 0;
+        for (auto it = m_renderPasses.begin(); it != m_renderPasses.end();) {
+            const Bool isActive = s_hasActiveRenderPass && it->first == activeHash;
+            if (!isActive && m_frameCounter - it->second.lastUsedFrame > kRetireAgeFrames) {
+                if (m_rpFastValid && m_rpFastRenderPassHash == it->first) {
+                    m_rpFastValid = false;
+                }
+                it = m_renderPasses.erase(it);
+            } else {
+                ++it;
+            }
+        }
+    }
+
     Bool VkRenderPassManager::BeginRenderPass(VkCommandBuffer commandBuffer, RenderPassEntry& renderPassEntry) {
         // TODO: Transition all the attachments into proper layout before starting the render pass
         VkRenderPassBeginInfo renderPassBeginInfo;

MobileGL/MG_Backend/DirectVulkan/Renderer/VkRenderPassManager.h

@@ -27,7 +27,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     };
 
     struct PendingClearAttachmentInfo {
+        // Index into the render pass attachment descriptions (VkRenderPassBeginInfo::pClearValues space).
         Uint32 attachmentIndex = 0;
+        // Index into the subpass pColorAttachments (VkClearAttachment::colorAttachment space) — the GL
+        // draw-buffer slot. Differs from attachmentIndex when earlier slots are GL_NONE/incomplete.
+        // Only meaningful for color clears.
+        Uint32 colorAttachmentSlot = 0;
         PendingClearKey key{};
         MG_State::GLState::RenderbufferObject* renderbuffer = nullptr;
         Bool hasInlinePayload = false;
@@ -68,7 +73,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Bool hasDepthStencilAttachment = false;
         VkSampleCountFlagBits sampleCount = VK_SAMPLE_COUNT_1_BIT;
         IntVec2 extent = {0, 0};
-        Uint32 subpass = 0;
+        // VkFramebufferCreateInfo::layers of the entry's framebuffer (>1 for layered GL attachments).
+        Uint32 layers = 1;
+        // Frame counter value of the last GetOrCreateRenderPass hit; drives cache eviction.
+        Uint64 lastUsedFrame = 0;
 
         RenderPassEntry() = default;
         RenderPassEntry(const RenderPassEntry&) = delete;
@@ -84,7 +92,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             std::swap(hasDepthStencilAttachment, that.hasDepthStencilAttachment);
             std::swap(sampleCount, that.sampleCount);
             std::swap(extent, that.extent);
-            std::swap(subpass, that.subpass);
+            std::swap(layers, that.layers);
+            std::swap(lastUsedFrame, that.lastUsedFrame);
         }
         RenderPassEntry(
             Uint64 hash,
@@ -97,7 +106,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             Uint32 colorAttachmentCount,
             Bool hasDepthStencilAttachment,
             VkSampleCountFlagBits sampleCount,
-            IntVec2 extent, int subpass):
+            IntVec2 extent, Uint32 layers):
             hash(hash),
             renderPass(renderpass),
             framebuffer(framebuffer),
@@ -109,7 +118,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             hasDepthStencilAttachment(hasDepthStencilAttachment),
             sampleCount(sampleCount),
             extent(extent),
-            subpass(subpass)
+            layers(layers)
         {}
 
         ~RenderPassEntry() {
@@ -166,6 +175,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         void QueueRenderbufferClear(const ClearAttachmentPayload& clearPayload,
                                     const MG_State::GLState::FramebufferAttachmentObject& attachment);
         void PopPendingRenderbufferClear(MG_State::GLState::RenderbufferObject* renderbuffer);
+        // Frame boundary hook: ages the render-pass cache and evicts long-unused
+        // entries (their command buffers retired many frames ago).
+        void OnPresent();
         static Bool BeginRenderPass(VkCommandBuffer commandBuffer, RenderPassEntry& renderPassEntry);
         static Bool EndRenderPass(VkCommandBuffer commandBuffer);
         static ActiveRenderPassInfo* GetActiveRenderPass();
@@ -178,6 +190,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         VkTextureManager& m_textureManager;
         SwapchainObject& m_swapchainObject;
         UnorderedMap<Uint64, RenderPassEntry> m_renderPasses;
+        // Monotonic frame counter (bumped in OnPresent) for render-pass cache aging.
+        Uint64 m_frameCounter = 0;
 
         // Bumped whenever a renderbuffer VkImage is (re)created; together with the texture
         // manager's image epoch this invalidates the render-pass fast path on any attachment
@@ -197,6 +211,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Uint64 m_rpFastRbEpoch = 0;
         Uint64 m_rpFastRenderPassHash = 0;
 
+    public:
         struct RenderbufferResource {
             WeakPtr<MG_State::GLState::RenderbufferObject> renderbuffer;
             VkImage image = VK_NULL_HANDLE;
@@ -213,6 +228,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             void Destroy(VkDevice device, VmaAllocator allocator);
         };
 
+        // Public so the renderer's blit/copy/readback bindings can source renderbuffer
+        // attachments the same way texture attachments go through the texture manager.
+        RenderbufferResource* GetOrCreateRenderbufferResource(
+            const SharedPtr<MG_State::GLState::RenderbufferObject>& renderbuffer);
+        Bool GetPendingRenderbufferClear(MG_State::GLState::RenderbufferObject* renderbuffer,
+                                         ClearAttachmentPayload& outPayload) const;
+
+    private:
         struct PendingRenderbufferClear {
             WeakPtr<MG_State::GLState::RenderbufferObject> renderbuffer;
             ClearAttachmentPayload payload{};
@@ -221,10 +244,6 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         UnorderedMap<MG_State::GLState::RenderbufferObject*, RenderbufferResource> m_renderbufferResources;
         UnorderedMap<MG_State::GLState::RenderbufferObject*, PendingRenderbufferClear> m_pendingRenderbufferClears;
 
-        RenderbufferResource* GetOrCreateRenderbufferResource(
-            const SharedPtr<MG_State::GLState::RenderbufferObject>& renderbuffer);
-        Bool GetPendingRenderbufferClear(MG_State::GLState::RenderbufferObject* renderbuffer,
-                                         ClearAttachmentPayload& outPayload) const;
         Bool HasPendingRenderbufferClear(
             const MG_State::GLState::FramebufferAttachmentObject& attachment) const;
         void CollectRenderbufferGarbage();

MobileGL/MG_Backend/DirectVulkan/Renderer/VkSamplerManager.cpp

@@ -58,11 +58,26 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         m_device = initInfo.device;
         m_config = initInfo.config;
+        m_samplerAnisotropySupported = initInfo.samplerAnisotropySupported;
+        m_maxSamplerAnisotropy = std::max(initInfo.maxSamplerAnisotropy, 1.0f);
         MOBILEGL_ASSERT(m_device != VK_NULL_HANDLE && m_config != nullptr,
                         "VkSamplerManager::Initialize failed: invalid initialization info");
         return true;
     }
 
+    Float VkSamplerManager::ResolveEffectiveMaxAnisotropy(const MG_State::GLState::SamplerObject& sampler,
+                                                           Bool forceNearestFiltering) const {
+        if (!m_samplerAnisotropySupported) return 1.0f;
+        if (forceNearestFiltering) return 1.0f;
+        // VUID-VkSamplerCreateInfo-anisotropyEnable-01071/01072: anisotropy requires both filters to
+        // be LINEAR and the value to sit within [1, limits.maxSamplerAnisotropy].
+        if (sampler.GetMinFilter() != SamplerFilterMode::Linear ||
+            sampler.GetMagFilter() != SamplerFilterMode::Linear) {
+            return 1.0f;
+        }
+        return std::clamp(sampler.GetMaxAnisotropy(), 1.0f, m_maxSamplerAnisotropy);
+    }
+
     void VkSamplerManager::Shutdown() {
         for (auto& [_, sampler] : m_samplers) {
             if (m_device != VK_NULL_HANDLE && sampler.handle != VK_NULL_HANDLE) {
@@ -77,10 +92,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     }
 
     Uint64 VkSamplerManager::BuildSamplerKey(const MG_State::GLState::SamplerObject& sampler,
-                                             const MG_State::GLState::ITextureObject& texture) const {
+                                             const MG_State::GLState::ITextureObject& texture,
+                                             Bool forceNearestFiltering) const {
         MOBILEGL_ASSERT(m_config != nullptr, "VkSamplerManager::BuildSamplerKey: m_config is null");
         XXHASH_VERIFY(XXH64_reset(m_hashState, m_config->CacheVersion));
 
+        XXHASH_VERIFY(XXH64_update(m_hashState, &forceNearestFiltering, sizeof(forceNearestFiltering)));
+
         const auto minFilter = sampler.GetMinFilter();
         XXHASH_VERIFY(XXH64_update(m_hashState, &minFilter, sizeof(minFilter)));
         const auto magFilter = sampler.GetMagFilter();
@@ -99,9 +117,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         XXHASH_VERIFY(XXH64_update(m_hashState, &maxLod, sizeof(maxLod)));
         const auto lodBias = sampler.GetLodBias();
         XXHASH_VERIFY(XXH64_update(m_hashState, &lodBias, sizeof(lodBias)));
-        // Anisotropy is currently an accepted frontend-only state on DirectVulkan.
-        // Keep it out of the key so changing this no-op does not manufacture duplicate
-        // VkSamplers while sampler versioning still exposes the new frontend value.
+        // The RESOLVED value, not the GL request: samplers that only differ in an anisotropy Vulkan
+        // will not apply (NEAREST filtering, or requests past the device limit) must still share one
+        // VkSampler, while two samplers that really do differ must not collide onto the first one's.
+        const auto maxAnisotropy = ResolveEffectiveMaxAnisotropy(sampler, forceNearestFiltering);
+        XXHASH_VERIFY(XXH64_update(m_hashState, &maxAnisotropy, sizeof(maxAnisotropy)));
         const auto compareMode = sampler.GetCompareMode();
         XXHASH_VERIFY(XXH64_update(m_hashState, &compareMode, sizeof(compareMode)));
         const auto compareFunc = ResolveCompareFunc(sampler, texture);
@@ -112,8 +132,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     }
 
     VkSampler VkSamplerManager::GetOrCreateSampler(const MG_State::GLState::SamplerObject& sampler,
-                                                   const MG_State::GLState::ITextureObject& texture) {
-        const Uint64 key = BuildSamplerKey(sampler, texture);
+                                                   const MG_State::GLState::ITextureObject& texture,
+                                                   Bool forceNearestFiltering) {
+        const Uint64 key = BuildSamplerKey(sampler, texture, forceNearestFiltering);
         auto it = m_samplers.find(key);
         if (it != m_samplers.end()) {
             return it->second.handle;
@@ -121,17 +142,19 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         VkSamplerCreateInfo samplerInfo{};
         samplerInfo.sType = VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO;
-        samplerInfo.magFilter = ToVkFilter(sampler.GetMagFilter());
-        samplerInfo.minFilter = ToVkFilter(sampler.GetMinFilter());
-        samplerInfo.mipmapMode = ToVkMipmapMode(sampler.GetMipmapMode());
+        samplerInfo.magFilter = forceNearestFiltering ? VK_FILTER_NEAREST : ToVkFilter(sampler.GetMagFilter());
+        samplerInfo.minFilter = forceNearestFiltering ? VK_FILTER_NEAREST : ToVkFilter(sampler.GetMinFilter());
+        samplerInfo.mipmapMode = forceNearestFiltering ? VK_SAMPLER_MIPMAP_MODE_NEAREST
+                                                       : ToVkMipmapMode(sampler.GetMipmapMode());
         samplerInfo.addressModeU = ToVkAddressMode(sampler.GetWrapS());
         samplerInfo.addressModeV = ToVkAddressMode(sampler.GetWrapT());
         samplerInfo.addressModeW = ToVkAddressMode(sampler.GetWrapR());
         samplerInfo.mipLodBias = sampler.GetLodBias();
-        // DirectVulkan does not yet plumb samplerAnisotropy feature/limit discovery;
-        // preserve the accepted frontend state without requesting an unsupported feature.
-        samplerInfo.anisotropyEnable = VK_FALSE;
-        samplerInfo.maxAnisotropy = 1.0f;
+        // Must use the same resolver as BuildSamplerKey - a divergence would either collide two
+        // different samplers or silently create duplicates.
+        const Float maxAnisotropy = ResolveEffectiveMaxAnisotropy(sampler, forceNearestFiltering);
+        samplerInfo.anisotropyEnable = maxAnisotropy > 1.0f ? VK_TRUE : VK_FALSE;
+        samplerInfo.maxAnisotropy = maxAnisotropy;
         samplerInfo.compareEnable = sampler.GetCompareMode() == SamplerCompareMode::CompareToTexture ? VK_TRUE : VK_FALSE;
         samplerInfo.compareOp = ToVkCompareOp(ResolveCompareFunc(sampler, texture));
         samplerInfo.maxLod = ResolveEffectiveMaxLod(sampler);

MobileGL/MG_Backend/DirectVulkan/Renderer/VkSamplerManager.h

@@ -24,13 +24,18 @@ public:
     struct InitInfo {
         VkDevice device = VK_NULL_HANDLE;
         const VulkanRendererConfig* config = nullptr;
+        // The samplerAnisotropy device feature was requested and granted at vkCreateDevice.
+        Bool samplerAnisotropySupported = false;
+        // VkPhysicalDeviceLimits::maxSamplerAnisotropy.
+        Float maxSamplerAnisotropy = 1.0f;
     };
 
     Bool Initialize(const InitInfo& initInfo);
     void Shutdown();
 
     VkSampler GetOrCreateSampler(const MG_State::GLState::SamplerObject& sampler,
-                                 const MG_State::GLState::ITextureObject& texture);
+                                 const MG_State::GLState::ITextureObject& texture,
+                                 Bool forceNearestFiltering = false);
 
 private:
     struct SamplerCacheEntry {
@@ -40,7 +45,8 @@ private:
     };
 
     Uint64 BuildSamplerKey(const MG_State::GLState::SamplerObject& sampler,
-                           const MG_State::GLState::ITextureObject& texture) const;
+                           const MG_State::GLState::ITextureObject& texture,
+                           Bool forceNearestFiltering) const;
     static VkFilter ToVkFilter(SamplerFilterMode mode);
     static VkSamplerMipmapMode ToVkMipmapMode(SamplerMipmapMode mode);
     static VkSamplerAddressMode ToVkAddressMode(SamplerWrapMode mode);
@@ -49,9 +55,17 @@ private:
                                                  const MG_State::GLState::ITextureObject& texture);
     static VkBorderColor ResolveVkBorderColor(const MG_State::GLState::SamplerObject& sampler,
                                               const MG_State::GLState::ITextureObject& texture);
+    // The anisotropy Vulkan will actually apply: 1.0 (i.e. disabled) unless the feature is on and
+    // the sampler filters linearly both ways, otherwise the GL request clamped to the device limit.
+    // GL happily carries GL_TEXTURE_MAX_ANISOTROPY on a NEAREST sampler (Blaze3D's blocks do exactly
+    // that) while Vulkan forbids anisotropyEnable there, so the GL value must never be forwarded raw.
+    Float ResolveEffectiveMaxAnisotropy(const MG_State::GLState::SamplerObject& sampler,
+                                        Bool forceNearestFiltering) const;
 
     VkDevice m_device = VK_NULL_HANDLE;
     const VulkanRendererConfig* m_config = nullptr;
+    Bool m_samplerAnisotropySupported = false;
+    Float m_maxSamplerAnisotropy = 1.0f;
     UnorderedMap<Uint64, SamplerCacheEntry> m_samplers;
     static inline XXH64_state_t* m_hashState = XXH64_createState();
 };

MobileGL/MG_Backend/DirectVulkan/Renderer/VkTextureManager.cpp

@@ -8,6 +8,8 @@
 
 #include "VkTextureManager.h"
 
+#include "ProgramFactory.h"
+
 #include "MG_State/GLState/Core.h"
 #include "MG_Util/Converters/MGToStr/TextureEnumConverter.h"
 #include "MG_Util/Converters/MGToVk/TextureEnumConverter.h"
@@ -17,6 +19,7 @@
 #include <cstdlib>
 #include <cstring>
 #include <memory>
+#include <vulkan/utility/vk_format_utils.h>
 
 namespace MobileGL::MG_Backend::DirectVulkan {
     // Compute shaders may legally sample framebuffer-attached textures (the GL feedback-loop rule
@@ -63,6 +66,59 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                target == TextureUploadTarget::ProxyTexture2DMultisampleArray;
     }
 
+    static Bool IsMutableStorageImageFormat(VkFormat format) {
+        if (!vkuFormatIsColor(format) || vkuFormatIsCompressed(format)) {
+            return false;
+        }
+
+        // These are the uncompressed color compatibility classes covered by the core GLSL/SPIR-V
+        // storage-image formats. OpenGL mutable texture storage uses image-format compatibility by
+        // size, so a shader may legally reinterpret (for example) RGBA16_UNORM storage as rgba16f. Vulkan
+        // requires the image to be mutable and the view formats to share this exact compatibility
+        // class for the equivalent operation.
+        switch (vkuFormatCompatibilityClass(format)) {
+        case VKU_FORMAT_COMPATIBILITY_CLASS_8BIT:
+        case VKU_FORMAT_COMPATIBILITY_CLASS_16BIT:
+        case VKU_FORMAT_COMPATIBILITY_CLASS_32BIT:
+        case VKU_FORMAT_COMPATIBILITY_CLASS_64BIT:
+        case VKU_FORMAT_COMPATIBILITY_CLASS_128BIT:
+            return true;
+        default:
+            return false;
+        }
+    }
+
+    static Bool HasMatchingColorComponentLayout(VkFormat lhs, VkFormat rhs) {
+        const VKU_FORMAT_INFO lhsInfo = vkuGetFormatInfo(lhs);
+        const VKU_FORMAT_INFO rhsInfo = vkuGetFormatInfo(rhs);
+        if (lhsInfo.component_count == 0 || lhsInfo.component_count != rhsInfo.component_count ||
+            lhsInfo.texel_block_size != rhsInfo.texel_block_size ||
+            lhsInfo.texels_per_block != 1 || rhsInfo.texels_per_block != 1) {
+            return false;
+        }
+        for (Uint32 component = 0; component < lhsInfo.component_count; ++component) {
+            if (lhsInfo.components[component].type != rhsInfo.components[component].type ||
+                lhsInfo.components[component].size != rhsInfo.components[component].size) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    static Bool FormatMatchesSamplerNumericDomain(VkFormat format, SamplerNumericDomain numericDomain) {
+        switch (numericDomain) {
+        case SamplerNumericDomain::Float:
+            return vkuFormatIsSampledFloat(format);
+        case SamplerNumericDomain::SignedInteger:
+            return vkuFormatIsSINT(format);
+        case SamplerNumericDomain::UnsignedInteger:
+            return vkuFormatIsUINT(format);
+        case SamplerNumericDomain::Unknown:
+            return true;
+        }
+        return false;
+    }
+
     static Bool TryResolveSampleCountFlagBits(Int requestedSamples, VkSampleCountFlagBits& outSampleCount) {
         switch (requestedSamples) {
         case 1:
@@ -319,7 +375,23 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         switch (format) {
         case TextureInternalFormat::RGB:
         case TextureInternalFormat::RGB8:
+        // Legacy low-bit RGB formats share the UNorm8 canonical shadow layout (see
+        // TextureFormatProcessor), so they upload exactly like RGB8 with an alpha expand.
+        case TextureInternalFormat::R3G3B2:
+        case TextureInternalFormat::RGB4:
+        case TextureInternalFormat::RGB5:
             return {VK_FORMAT_R8G8B8A8_UNORM, true, 1, {0xFF, 0x00, 0x00, 0x00}};
+        // Low-bit RGBA formats: UNorm8x4 canonical shadow, no expansion needed.
+        case TextureInternalFormat::RGBA2:
+        case TextureInternalFormat::RGBA4:
+        case TextureInternalFormat::RGB5A1:
+            return {VK_FORMAT_R8G8B8A8_UNORM, false, 0, {0, 0, 0, 0}};
+        // 10/12-bit RGB(A): UNorm16 canonical shadow.
+        case TextureInternalFormat::RGB10:
+        case TextureInternalFormat::RGB12:
+            return {VK_FORMAT_R16G16B16A16_UNORM, true, 2, {0xFF, 0xFF, 0x00, 0x00}};
+        case TextureInternalFormat::RGBA12:
+            return {VK_FORMAT_R16G16B16A16_UNORM, false, 0, {0, 0, 0, 0}};
         case TextureInternalFormat::SRGB8:
             return {VK_FORMAT_R8G8B8A8_SRGB, true, 1, {0xFF, 0x00, 0x00, 0x00}};
         case TextureInternalFormat::RGB8Snorm:
@@ -767,6 +839,180 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return perMipSampledView;
     }
 
+    VkImageView VkTextureManager::GetOrCreateSampledImageView(MG_State::GLState::ITextureObject& texture,
+                                                               VkFormat format) {
+        TextureResource* resource = SyncTextureAndGetDescriptor(texture);
+        if (resource == nullptr || resource->image == VK_NULL_HANDLE ||
+            resource->sampledView == VK_NULL_HANDLE) {
+            return VK_NULL_HANDLE;
+        }
+
+        if (format == VK_FORMAT_UNDEFINED || format == resource->format) {
+            return resource->sampledView;
+        }
+        if (!AreSampledImageViewFormatsCompatible(resource->format, format)) {
+            MGLOG_E("%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",
+                    __func__, texture.GetExternalIndex(), static_cast<Int>(resource->format),
+                    static_cast<Int>(format));
+            return VK_NULL_HANDLE;
+        }
+
+        const TextureResource::SampledImageViewKey key{
+            .baseMipLevel = resource->sampledBaseMipLevel,
+            .levelCount = resource->sampledLevelCount,
+            .viewType = resource->viewType,
+            .format = format,
+        };
+        const auto existing = resource->alternateSampledViews.find(key);
+        if (existing != resource->alternateSampledViews.end()) {
+            return existing->second;
+        }
+
+        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 "
+                    "for textureId=%d (available=0x%x)",
+                    __func__, static_cast<Int>(format), texture.GetExternalIndex(),
+                    static_cast<Uint32>(formatProperties.optimalTilingFeatures));
+            return VK_NULL_HANDLE;
+        }
+
+        const TextureFormatInfo formatInfo = ResolveTextureFormatInfo(texture.GetFormat());
+        const VkComponentMapping sampledComponents = ResolveSampledViewComponents(texture, formatInfo);
+        const VkImageView view = CreateImageView(
+            resource->image, format, VK_IMAGE_ASPECT_COLOR_BIT, resource->viewType,
+            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",
+                    __func__, texture.GetExternalIndex(), static_cast<Int>(resource->format),
+                    static_cast<Int>(format));
+            return VK_NULL_HANDLE;
+        }
+
+        resource->alternateSampledViews.emplace(key, view);
+        MGLOG_D("%s: created sampled image view textureId=%d imageFormat=%d viewFormat=%d mip=[%u,%u)",
+                __func__, texture.GetExternalIndex(), static_cast<Int>(resource->format),
+                static_cast<Int>(format), resource->sampledBaseMipLevel,
+                resource->sampledBaseMipLevel + resource->sampledLevelCount);
+        return view;
+    }
+
+    VkImageView VkTextureManager::GetOrCreateStorageImageView(MG_State::GLState::ITextureObject& texture,
+                                                               Uint32 mipLevel, VkFormat format,
+                                                               Bool layered, Int32 layer) {
+        TextureResource* resource = SyncTextureAndGetDescriptor(texture);
+        if (resource == nullptr || resource->image == VK_NULL_HANDLE || mipLevel >= resource->mipLevels ||
+            resource->sampleCount != VK_SAMPLE_COUNT_1_BIT ||
+            (resource->aspect & VK_IMAGE_ASPECT_COLOR_BIT) == 0) {
+            return VK_NULL_HANDLE;
+        }
+
+        if (format == VK_FORMAT_UNDEFINED) {
+            format = resource->format;
+        }
+        if (!AreStorageImageViewFormatsCompatible(resource->format, format)) {
+            MGLOG_E("%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",
+                    __func__, texture.GetExternalIndex(), static_cast<Int>(resource->format),
+                    static_cast<Int>(format));
+            return VK_NULL_HANDLE;
+        }
+
+        Uint32 baseArrayLayer = 0;
+        Uint32 layerCount = resource->arrayLayers;
+        VkImageViewType viewType = resource->viewType;
+        if (!layered) {
+            switch (resource->viewType) {
+            case VK_IMAGE_VIEW_TYPE_1D_ARRAY:
+                viewType = VK_IMAGE_VIEW_TYPE_1D;
+                break;
+            case VK_IMAGE_VIEW_TYPE_2D_ARRAY:
+            case VK_IMAGE_VIEW_TYPE_CUBE:
+            case VK_IMAGE_VIEW_TYPE_CUBE_ARRAY:
+                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",
+                        __func__, texture.GetExternalIndex());
+                return VK_NULL_HANDLE;
+            default:
+                break;
+            }
+
+            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",
+                            __func__, layer, texture.GetExternalIndex(), resource->arrayLayers);
+                    return VK_NULL_HANDLE;
+                }
+                baseArrayLayer = static_cast<Uint32>(layer);
+                layerCount = 1;
+            }
+        }
+
+        const Bool isFullResourceView = baseArrayLayer == 0 && layerCount == resource->arrayLayers &&
+                                        viewType == resource->viewType;
+        if (format == resource->format && isFullResourceView) {
+            return GetOrCreateViewAtMipLevel(texture, mipLevel);
+        }
+
+        const TextureResource::StorageImageViewKey key{
+            .mipLevel = mipLevel,
+            .baseArrayLayer = baseArrayLayer,
+            .layerCount = layerCount,
+            .viewType = viewType,
+            .format = format,
+        };
+        auto it = resource->storageImageViews.find(key);
+        if (it != resource->storageImageViews.end()) {
+            return it->second;
+        }
+
+        VkFormatFeatureFlags requiredFormatFeatures = VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT;
+        if (format != resource->format &&
+            (format == VK_FORMAT_R32_UINT || format == VK_FORMAT_R32_SINT)) {
+            requiredFormatFeatures |= VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT;
+        }
+        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 "
+                    "(available=0x%x)",
+                    __func__, static_cast<Int>(format), static_cast<Uint32>(requiredFormatFeatures),
+                    texture.GetExternalIndex(), static_cast<Uint32>(formatProperties.optimalTilingFeatures));
+            return VK_NULL_HANDLE;
+        }
+
+        const VkImageView view = CreateImageView(resource->image, format, VK_IMAGE_ASPECT_COLOR_BIT, viewType,
+                                                 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",
+                    __func__, texture.GetExternalIndex(), mipLevel, static_cast<Int>(resource->format),
+                    static_cast<Int>(format));
+            return VK_NULL_HANDLE;
+        }
+        resource->storageImageViews.emplace(key, view);
+        MGLOG_D("%s: created storage image view textureId=%d mip=%u imageFormat=%d viewFormat=%d",
+                __func__, texture.GetExternalIndex(), mipLevel, static_cast<Int>(resource->format),
+                static_cast<Int>(format));
+        return view;
+    }
+
     void VkTextureManager::UpdateTrackedImageLayout(MG_State::GLState::ITextureObject* texture, VkImageLayout newLayout) {
         MOBILEGL_ASSERT(texture != nullptr, "UpdateTrackedImageLayout: texture is null");
         auto it = m_textureResources.find(MakeTextureIdentity(texture));
@@ -910,6 +1156,24 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return ok;
     }
 
+    Bool VkTextureManager::NeedsStorageImagePreparation(MG_State::GLState::ITextureObject& texture) const {
+        const auto it = m_textureResources.find(MakeTextureIdentity(&texture));
+        if (it == m_textureResources.end()) {
+            return true;
+        }
+        const TextureResource& resource = it->second;
+        if (resource.image == VK_NULL_HANDLE || resource.layout != VK_IMAGE_LAYOUT_GENERAL) {
+            return true;
+        }
+        // Mirror SyncTexture's cross-draw skip condition: any version drift means the sync
+        // path may upload or rebuild, both of which need the render pass ended first.
+        const auto* mipTexture = MG_State::GLState::AsMipmapTexture(&texture);
+        const Uint32 mipLevelCount = mipTexture != nullptr ? mipTexture->GetMipmapLevelCount() : 0u;
+        return resource.syncedContentVersion != texture.GetContentVersion() ||
+               resource.syncedTextureParamsVersion != texture.GetTextureParamsVersion() ||
+               resource.syncedMipLevelCount != mipLevelCount;
+    }
+
     Bool VkTextureManager::TransitionImageLayout(VkCommandBuffer commandBuffer, VkImage image,
                                                  VkImageLayout& trackedLayout, VkImageLayout newLayout,
                                                  VkPipelineStageFlags srcStageMask, VkPipelineStageFlags dstStageMask,
@@ -1085,6 +1349,19 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             return false;
         }
 
+        const VkImageAspectFlags aspect = GetAspectMaskForFormat(format);
+        VkFormatProperties formatProperties{};
+        vkGetPhysicalDeviceFormatProperties(m_physicalDevice, format, &formatProperties);
+        const Bool supportsStorageImage =
+            !isMultisampleTexture &&
+            (aspect & VK_IMAGE_ASPECT_COLOR_BIT) != 0 &&
+            (formatProperties.optimalTilingFeatures & VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT) != 0;
+        VkImageCreateFlags imageCreateFlags = shapeInfo.imageFlags;
+        if (supportsStorageImage && IsMutableStorageImageFormat(format) &&
+            m_mutableFormatUnsupported.find(format) == m_mutableFormatUnsupported.end()) {
+            imageCreateFlags |= VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT;
+        }
+
         const Bool compatible = resource.image != VK_NULL_HANDLE && resource.format == format &&
                                 resource.extent.width == static_cast<Uint32>(texelSize.x()) &&
                                 resource.extent.height == static_cast<Uint32>(texelSize.y()) &&
@@ -1092,6 +1369,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                 resource.arrayLayers == shapeInfo.arrayLayers &&
                                 resource.viewType == shapeInfo.viewType &&
                                 resource.sampleCount == resolvedSampleCount &&
+                                resource.imageCreateFlags == imageCreateFlags &&
                                 resource.mipLevels == backingMipLevels;
         if (compatible) {
             if (resource.perMipViews.size() != backingMipLevels) {
@@ -1112,6 +1390,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             resource.arrayLayers == shapeInfo.arrayLayers &&
             resource.viewType == shapeInfo.viewType &&
             resource.sampleCount == resolvedSampleCount &&
+            resource.imageCreateFlags == imageCreateFlags &&
             resolvedSampleCount == VK_SAMPLE_COUNT_1_BIT &&
             resource.mipLevels < backingMipLevels &&
             resource.layout != VK_IMAGE_LAYOUT_UNDEFINED;
@@ -1123,26 +1402,18 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             DeferResourceRelease(Move(resource));
         }
 
-        auto aspect = GetAspectMaskForFormat(format);
-
         VkImageCreateInfo imageInfo{};
         imageInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
-    imageInfo.flags = shapeInfo.imageFlags;
-    imageInfo.imageType = shapeInfo.imageType;
+        imageInfo.flags = imageCreateFlags;
+        imageInfo.imageType = shapeInfo.imageType;
         imageInfo.extent.width = static_cast<Uint32>(texelSize.x());
         imageInfo.extent.height = static_cast<Uint32>(texelSize.y());
-    imageInfo.extent.depth = shapeInfo.depth;
+        imageInfo.extent.depth = shapeInfo.depth;
         imageInfo.mipLevels = backingMipLevels;
-    imageInfo.arrayLayers = shapeInfo.arrayLayers;
+        imageInfo.arrayLayers = shapeInfo.arrayLayers;
         imageInfo.format = format;
         imageInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
         imageInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
-        VkFormatProperties formatProperties{};
-        vkGetPhysicalDeviceFormatProperties(m_physicalDevice, format, &formatProperties);
-        const Bool supportsStorageImage =
-            !isMultisampleTexture &&
-            (aspect & VK_IMAGE_ASPECT_COLOR_BIT) != 0 &&
-            (formatProperties.optimalTilingFeatures & VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT) != 0;
         imageInfo.usage = VK_IMAGE_USAGE_SAMPLED_BIT |
                           (supportsStorageImage ? VK_IMAGE_USAGE_STORAGE_BIT : 0) |
                           ((aspect & VK_IMAGE_ASPECT_COLOR_BIT) ? VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT : 0) |
@@ -1153,15 +1424,35 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             imageInfo.usage |= VK_IMAGE_USAGE_TRANSFER_DST_BIT | VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
         }
         imageInfo.samples = resolvedSampleCount;
-        if (isMultisampleTexture) {
+        if (isMultisampleTexture || (imageInfo.flags & VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT) != 0) {
             VkImageFormatProperties imageFormatProperties{};
-            const VkResult imageFormatResult = vkGetPhysicalDeviceImageFormatProperties(
+            VkResult imageFormatResult = vkGetPhysicalDeviceImageFormatProperties(
                 m_physicalDevice, format, imageInfo.imageType, imageInfo.tiling, imageInfo.usage,
                 imageInfo.flags, &imageFormatProperties);
+            if (imageFormatResult != VK_SUCCESS && !isMultisampleTexture &&
+                (imageInfo.flags & VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT) != 0) {
+                // 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 "
+                        "without VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT (format reinterpretation "
+                        "will be unavailable for it)",
+                        __func__, static_cast<Int>(format), texture.GetExternalIndex());
+                // Remember the verdict so later syncs of same-format textures neither retry
+                // the probe nor flag-mismatch against this image and recreate it.
+                m_mutableFormatUnsupported.insert(format);
+                imageInfo.flags &= ~VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT;
+                imageCreateFlags = imageInfo.flags;
+                imageFormatResult = vkGetPhysicalDeviceImageFormatProperties(
+                    m_physicalDevice, format, imageInfo.imageType, imageInfo.tiling, imageInfo.usage,
+                    imageInfo.flags, &imageFormatProperties);
+            }
             if (imageFormatResult != VK_SUCCESS ||
-                (imageFormatProperties.sampleCounts & resolvedSampleCount) == 0) {
-                MGLOG_D("%s: sampleCount=%d is unsupported for textureId=%d target=%s format=%d usage=0x%x",
-                        __func__, texture.GetSamples(), texture.GetExternalIndex(),
+                (isMultisampleTexture && (imageFormatProperties.sampleCounts & resolvedSampleCount) == 0)) {
+                MGLOG_D("%s: image flags=0x%x sampleCount=%d are unsupported for textureId=%d target=%s "
+                        "format=%d usage=0x%x",
+                        __func__, static_cast<Uint32>(imageInfo.flags), texture.GetSamples(),
+                        texture.GetExternalIndex(),
                         MG_Util::ConvertTextureUploadTargetToString(uploadTarget).c_str(),
                         static_cast<Int>(format), static_cast<Uint32>(imageInfo.usage));
                 return false;
@@ -1188,6 +1479,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         resource.aspect = aspect;
         resource.viewType = shapeInfo.viewType;
         resource.sampleCount = resolvedSampleCount;
+        resource.imageCreateFlags = imageCreateFlags;
         resource.syncedTextureParamsVersion = 0;
 
         if (preservedResource) {
@@ -1203,7 +1495,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     void VkTextureManager::DeferResourceRelease(TextureResource&& resource) {
         if (resource.image == VK_NULL_HANDLE && resource.fullView == VK_NULL_HANDLE &&
             resource.sampledView == VK_NULL_HANDLE &&
-            resource.perMipViews.empty() && resource.perMipSampledViews.empty()) {
+            resource.perMipViews.empty() && resource.perMipSampledViews.empty() &&
+            resource.attachmentViews.empty() && resource.alternateSampledViews.empty() &&
+            resource.storageImageViews.empty()) {
             return;
         }
 
@@ -1299,6 +1593,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                 sampledView = VK_NULL_HANDLE;
             }
         }
+        for (const auto& [_, sampledView] : resource.alternateSampledViews) {
+            DeferViewRelease(sampledView);
+        }
+        resource.alternateSampledViews.clear();
 
         const TextureFormatInfo formatInfo = ResolveTextureFormatInfo(texture.GetFormat());
         const VkComponentMapping sampledComponents = ResolveSampledViewComponents(texture, formatInfo);
@@ -1324,7 +1622,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                                   VkImageViewType viewType, Uint32 baseMipLevel, Uint32 levelCount,
                                                   Uint32 baseArrayLayer,
                                                   Uint32 layerCount,
-                                                  const VkComponentMapping* components) const {
+                                                  const VkComponentMapping* components,
+                                                  VkImageUsageFlags viewUsage) const {
         VkImageViewCreateInfo viewInfo{};
         viewInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
         viewInfo.image = image;
@@ -1340,6 +1639,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         viewInfo.subresourceRange.baseArrayLayer = baseArrayLayer;
         viewInfo.subresourceRange.layerCount = layerCount;
 
+        VkImageViewUsageCreateInfo usageInfo{};
+        if (viewUsage != 0) {
+            usageInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO;
+            usageInfo.usage = viewUsage;
+            viewInfo.pNext = &usageInfo;
+        }
+
         VkImageView view = VK_NULL_HANDLE;
         VK_VERIFY(vkCreateImageView(m_device, &viewInfo, nullptr, &view), "vkCreateImageView(texture)");
         return view;
@@ -1665,4 +1971,64 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
         return imageAspect;
     }
+
+    VkFormat VkTextureManager::ResolveSampledImageViewFormat(VkFormat imageFormat,
+                                                              SamplerNumericDomain numericDomain) {
+        // Depth/stencil images always sample through the existing depth-aspect sampledView.
+        // Combined formats (D24S8, D32FS8) are multi-numeric, so vkuFormatIsSampledFloat is
+        // false for them by design, yet their depth aspect reads as float in every GL depth
+        // texture mode; Vulkan also forbids reinterpreting them through color-class views.
+        // Integer domains keep the same view (pre-reinterpretation behavior for stencil-index
+        // style access) rather than failing the draw.
+        if (vkuFormatIsDepthOrStencil(imageFormat)) {
+            return imageFormat;
+        }
+        if (imageFormat == VK_FORMAT_UNDEFINED || numericDomain == SamplerNumericDomain::Unknown ||
+            FormatMatchesSamplerNumericDomain(imageFormat, numericDomain)) {
+            return imageFormat;
+        }
+        if (!IsMutableStorageImageFormat(imageFormat)) {
+            return VK_FORMAT_UNDEFINED;
+        }
+
+        // Preserve component ordering and bit widths. This selects R32_UINT for an R32_SFLOAT
+        // texture sampled by a usampler rather than an arbitrary member (such as
+        // R8G8B8A8_UINT) of Vulkan's broad 32-bit compatibility class.
+        for (Int candidateValue = static_cast<Int>(VK_FORMAT_R4G4_UNORM_PACK8);
+             candidateValue <= static_cast<Int>(VK_FORMAT_ASTC_12x12_SRGB_BLOCK);
+             ++candidateValue) {
+            const VkFormat candidate = static_cast<VkFormat>(candidateValue);
+            if (!IsMutableStorageImageFormat(candidate) ||
+                !FormatMatchesSamplerNumericDomain(candidate, numericDomain) ||
+                !HasMatchingColorComponentLayout(imageFormat, candidate) ||
+                !AreSampledImageViewFormatsCompatible(imageFormat, candidate)) {
+                continue;
+            }
+
+            // If an integer backing is intentionally bit-read through a float sampler, require
+            // a true floating-point view. Normalized/scaled views satisfy OpTypeFloat but apply
+            // an unrelated numeric conversion to those bits.
+            if (numericDomain == SamplerNumericDomain::Float && !vkuFormatIsSFLOAT(candidate)) {
+                continue;
+            }
+            return candidate;
+        }
+        return VK_FORMAT_UNDEFINED;
+    }
+
+    Bool VkTextureManager::AreSampledImageViewFormatsCompatible(VkFormat imageFormat, VkFormat viewFormat) {
+        if (imageFormat == viewFormat) {
+            return true;
+        }
+        return IsMutableStorageImageFormat(imageFormat) && IsMutableStorageImageFormat(viewFormat) &&
+               vkuFormatCompatibilityClass(imageFormat) == vkuFormatCompatibilityClass(viewFormat);
+    }
+
+    Bool VkTextureManager::AreStorageImageViewFormatsCompatible(VkFormat imageFormat, VkFormat viewFormat) {
+        if (imageFormat == viewFormat) {
+            return true;
+        }
+        return IsMutableStorageImageFormat(imageFormat) && IsMutableStorageImageFormat(viewFormat) &&
+               vkuFormatCompatibilityClass(imageFormat) == vkuFormatCompatibilityClass(viewFormat);
+    }
 } // namespace MobileGL::MG_Backend::DirectVulkan

MobileGL/MG_Backend/DirectVulkan/Renderer/VkTextureManager.h

@@ -13,12 +13,15 @@
 #include <MG_State/GLState/TextureState/TextureObject.h>
 #include <vk_mem_alloc.h>
 #include <unordered_map>
+#include <unordered_set>
 
 namespace MobileGL::MG_State::GLState {
 class ITextureObject;
 }
 
 namespace MobileGL::MG_Backend::DirectVulkan {
+enum class SamplerNumericDomain : Uint8;
+
 class VkTextureManager {
 public:
     // Monotonic epoch bumped whenever a texture VkImage is (re)created. The render-pass
@@ -78,6 +81,61 @@ public:
             }
         };
 
+        struct StorageImageViewKey {
+            Uint32 mipLevel = 0;
+            Uint32 baseArrayLayer = 0;
+            Uint32 layerCount = 1;
+            VkImageViewType viewType = VK_IMAGE_VIEW_TYPE_2D;
+            VkFormat format = VK_FORMAT_UNDEFINED;
+
+            Bool operator==(const StorageImageViewKey& other) const {
+                return mipLevel == other.mipLevel &&
+                       baseArrayLayer == other.baseArrayLayer &&
+                       layerCount == other.layerCount &&
+                       viewType == other.viewType &&
+                       format == other.format;
+            }
+        };
+
+        struct SampledImageViewKey {
+            Uint32 baseMipLevel = 0;
+            Uint32 levelCount = 1;
+            VkImageViewType viewType = VK_IMAGE_VIEW_TYPE_2D;
+            VkFormat format = VK_FORMAT_UNDEFINED;
+
+            Bool operator==(const SampledImageViewKey& other) const {
+                return baseMipLevel == other.baseMipLevel &&
+                       levelCount == other.levelCount &&
+                       viewType == other.viewType &&
+                       format == other.format;
+            }
+        };
+
+        struct SampledImageViewKeyHash {
+            SizeT operator()(const SampledImageViewKey& key) const {
+                SizeT hash = std::hash<Uint32>{}(key.baseMipLevel);
+                hash ^= std::hash<Uint32>{}(key.levelCount) + 0x9e3779b9u + (hash << 6) + (hash >> 2);
+                hash ^= std::hash<Uint32>{}(static_cast<Uint32>(key.viewType)) +
+                        0x9e3779b9u + (hash << 6) + (hash >> 2);
+                hash ^= std::hash<Uint32>{}(static_cast<Uint32>(key.format)) +
+                        0x9e3779b9u + (hash << 6) + (hash >> 2);
+                return hash;
+            }
+        };
+
+        struct StorageImageViewKeyHash {
+            SizeT operator()(const StorageImageViewKey& key) const {
+                SizeT hash = std::hash<Uint32>{}(key.mipLevel);
+                hash ^= std::hash<Uint32>{}(key.baseArrayLayer) + 0x9e3779b9u + (hash << 6) + (hash >> 2);
+                hash ^= std::hash<Uint32>{}(key.layerCount) + 0x9e3779b9u + (hash << 6) + (hash >> 2);
+                hash ^= std::hash<Uint32>{}(static_cast<Uint32>(key.viewType)) +
+                        0x9e3779b9u + (hash << 6) + (hash >> 2);
+                hash ^= std::hash<Uint32>{}(static_cast<Uint32>(key.format)) +
+                        0x9e3779b9u + (hash << 6) + (hash >> 2);
+                return hash;
+            }
+        };
+
         VkImage image = VK_NULL_HANDLE;
         VmaAllocation allocation = nullptr;
         VkImageView fullView = VK_NULL_HANDLE;
@@ -85,6 +143,8 @@ public:
         Vector<VkImageView> perMipViews;
         Vector<VkImageView> perMipSampledViews;
         UnorderedMap<AttachmentViewKey, VkImageView, AttachmentViewKeyHash> attachmentViews;
+        UnorderedMap<SampledImageViewKey, VkImageView, SampledImageViewKeyHash> alternateSampledViews;
+        UnorderedMap<StorageImageViewKey, VkImageView, StorageImageViewKeyHash> storageImageViews;
         VkImageLayout layout = VK_IMAGE_LAYOUT_UNDEFINED;
         VkExtent2D extent = {0, 0};
         Uint32 depth = 1;
@@ -96,6 +156,7 @@ public:
         VkImageAspectFlags aspect = VK_IMAGE_ASPECT_NONE;
         VkImageViewType viewType = VK_IMAGE_VIEW_TYPE_2D;
         VkSampleCountFlagBits sampleCount = VK_SAMPLE_COUNT_1_BIT;
+        VkImageCreateFlags imageCreateFlags = 0;
         Uint16 syncedTextureParamsVersion = 0;
         // Snapshot of ITextureObject::GetContentVersion() at the last successful sync;
         // lets SyncTexture skip the whole re-check/re-upload when content is unchanged.
@@ -115,6 +176,8 @@ public:
             std::swap(this->perMipViews, that.perMipViews);
             std::swap(this->perMipSampledViews, that.perMipSampledViews);
             std::swap(this->attachmentViews, that.attachmentViews);
+            std::swap(this->alternateSampledViews, that.alternateSampledViews);
+            std::swap(this->storageImageViews, that.storageImageViews);
             std::swap(this->layout, that.layout);
             std::swap(this->extent, that.extent);
             std::swap(this->depth, that.depth);
@@ -126,6 +189,7 @@ public:
             std::swap(this->aspect, that.aspect);
             std::swap(this->viewType, that.viewType);
             std::swap(this->sampleCount, that.sampleCount);
+            std::swap(this->imageCreateFlags, that.imageCreateFlags);
             std::swap(this->syncedTextureParamsVersion, that.syncedTextureParamsVersion);
             std::swap(this->syncedContentVersion, that.syncedContentVersion);
             std::swap(this->syncedMipLevelCount, that.syncedMipLevelCount);
@@ -153,6 +217,16 @@ public:
                     vkDestroyImageView(s_device, attachmentView, nullptr);
                 }
             }
+            for (const auto& [_, sampledView] : alternateSampledViews) {
+                if (sampledView != VK_NULL_HANDLE) {
+                    vkDestroyImageView(s_device, sampledView, nullptr);
+                }
+            }
+            for (const auto& [_, storageImageView] : storageImageViews) {
+                if (storageImageView != VK_NULL_HANDLE) {
+                    vkDestroyImageView(s_device, storageImageView, nullptr);
+                }
+            }
             if (image != VK_NULL_HANDLE && allocation != nullptr) {
                 vmaDestroyImage(s_allocator, image, allocation);
             }
@@ -161,6 +235,8 @@ public:
             perMipViews.clear();
             perMipSampledViews.clear();
             attachmentViews.clear();
+            alternateSampledViews.clear();
+            storageImageViews.clear();
             image = VK_NULL_HANDLE;
             allocation = nullptr;
             layout = VK_IMAGE_LAYOUT_UNDEFINED;
@@ -174,6 +250,7 @@ public:
             aspect = VK_IMAGE_ASPECT_NONE;
             viewType = VK_IMAGE_VIEW_TYPE_2D;
             sampleCount = VK_SAMPLE_COUNT_1_BIT;
+            imageCreateFlags = 0;
             syncedTextureParamsVersion = 0;
             syncedContentVersion = 0;
             syncedMipLevelCount = 0;
@@ -198,6 +275,9 @@ public:
                                                     Uint32 baseArrayLayer, Uint32 layerCount,
                                                     VkImageViewType viewType);
     VkImageView GetOrCreateSampledViewAtMipLevel(MG_State::GLState::ITextureObject& texture, Uint32 mipLevel);
+    VkImageView GetOrCreateSampledImageView(MG_State::GLState::ITextureObject& texture, VkFormat format);
+    VkImageView GetOrCreateStorageImageView(MG_State::GLState::ITextureObject& texture, Uint32 mipLevel,
+                                            VkFormat format, Bool layered, Int32 layer);
     void UpdateTrackedImageLayout(MG_State::GLState::ITextureObject* texture, VkImageLayout newLayout);
     void UpdateTrackedImageLayoutAfterAttachmentWrite(VkCommandBuffer commandBuffer,
                                                       MG_State::GLState::ITextureObject* texture,
@@ -205,8 +285,16 @@ public:
                                                       VkImageLayout newLayout);
     Bool TransitionTextureForSampling(VkCommandBuffer commandBuffer, MG_State::GLState::ITextureObject& texture);
     Bool TransitionTextureForStorageImage(VkCommandBuffer commandBuffer, MG_State::GLState::ITextureObject& texture);
+    // Non-mutating probe for the per-draw storage-image fast path: true when preparing this
+    // texture as a storage image may need work that is illegal inside a render pass (resource
+    // creation, dirty-content upload, or a layout transition to GENERAL). Unknown state reports
+    // true - a false positive merely ends the render pass, a false negative would skip a barrier.
+    Bool NeedsStorageImagePreparation(MG_State::GLState::ITextureObject& texture) const;
 
     static VkImageAspectFlags ResolveSampledImageViewAspectMask(VkImageAspectFlags imageAspect);
+    static VkFormat ResolveSampledImageViewFormat(VkFormat imageFormat, SamplerNumericDomain numericDomain);
+    static Bool AreSampledImageViewFormatsCompatible(VkFormat imageFormat, VkFormat viewFormat);
+    static Bool AreStorageImageViewFormatsCompatible(VkFormat imageFormat, VkFormat viewFormat);
 
     static Bool TransitionImageLayout(VkCommandBuffer commandBuffer, VkImage image, VkImageLayout& trackedLayout,
                                VkImageLayout newLayout, VkPipelineStageFlags srcStageMask,
@@ -255,7 +343,8 @@ private:
                                 VkImageViewType viewType, Uint32 baseMipLevel, Uint32 levelCount,
                                 Uint32 baseArrayLayer,
                                 Uint32 layerCount,
-                                const VkComponentMapping* components = nullptr) const;
+                                const VkComponentMapping* components = nullptr,
+                                VkImageUsageFlags viewUsage = 0) const;
     Bool UploadDirtyMipLevels(MG_State::GLState::TextureObjectMipmap &mipmapTexture,
                       TextureUploadTarget uploadTarget,
                       TextureResource &outResource);
@@ -296,6 +385,9 @@ private:
         TextureResource* resource = nullptr;
     };
     Vector<DrawSyncedTexture> m_drawSyncedThisDraw;
+    // Formats whose mutable-image probe failed on this device; their images are created
+    // without MUTABLE_FORMAT_BIT so repeat syncs neither re-probe nor flag-mismatch.
+    std::unordered_set<VkFormat> m_mutableFormatUnsupported;
     std::unordered_map<TextureIdentity, WeakPtr<MG_State::GLState::ITextureObject>, TextureIdentityHash> m_aliveObjects;
     std::unordered_map<TextureIdentity, TextureResource, TextureIdentityHash> m_textureResources;
     Vector<Vector<TextureResource>> m_deferredReleases;

MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.h

@@ -51,6 +51,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Uint32 instanceCount = 1;
         Uint32 firstVertex = 0;
         Uint32 firstInstance = 0;
+        // Indexed-draw metadata for bounding vertex-stream conversion. baseVertex is the
+        // draw's base-vertex offset; indexRangeIsExactView is true only when the draw
+        // fetches exactly the indices its IndexBufferView describes (direct DrawElements;
+        // multi/indirect forms leave it false because the CPU cannot bound their ranges).
+        Int32 baseVertex = 0;
+        Bool indexRangeIsExactView = false;
     };
 
     struct DrawIndexedCmdParam {
@@ -131,6 +137,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         void ClearAttachmentsOnActiveRenderPass(VkCommandBuffer commandBuffer,
                                                 const RenderPassEntry& compatibleRenderPassEntry);
 
+        enum class ScissoredClearPrep {
+            NotNeeded,  // scissor covers the whole target — take the deferred whole-surface path instead
+            NoOp,       // nothing to clear (degenerate target or empty scissor rect)
+            Ready,      // a render pass is active; record vkCmdClearAttachments with the returned rect
+        };
+        ScissoredClearPrep PrepareScissoredClear(const MG_State::GLState::FramebufferObject& framebuffer,
+                                                 VkClearRect& outClearRect);
+
         void Clear(GLbitfield mask);
         void ClearBufferfi(GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil);
         void ClearBufferfv(GLenum buffer, GLint drawbuffer, const GLfloat* value);
@@ -157,6 +171,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                               GLsizei srcWidth, GLsizei srcHeight, GLsizei srcDepth);
         void GenerateMipmap(GLenum target);
         void ReadPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, void* pixels);
+        static SizeT GetReadbackTexelSize(VkFormat sourceFormat);
+        static Bool ConvertReadbackPixels(const Uint8* sourcePixels, VkFormat sourceFormat,
+                                          GLsizei width, GLsizei height, GLenum destinationFormat,
+                                          GLenum destinationType, SizeT destinationRowStride,
+                                          Uint8* destinationPixels);
         void GetTexImage(GLenum target, GLint level, GLenum format, GLenum type, GLvoid* pixels);
         void GetTextureImage(const SharedPtr<MG_State::GLState::ITextureObject>& texture,
                              TextureUploadTarget uploadTarget, GLint level, GLenum format, GLenum type,
@@ -219,6 +238,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // frontend. Timestamp support (queue timestampValidBits > 0 and a
         // non-zero timestampPeriod) is cached at device creation.
         Bool IsTimerQuerySupported() const;
+        // 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; }
         // 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.
@@ -235,7 +257,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Uint64 GetTimerQueryTimestampNs(const VkTimerQueryManager::TimestampRecord& record) const;
 
         void RequestSwapchainResize(Uint32 width, Uint32 height);
-        void RecreateSwapchain();
+        // Returns false when the surface is zero-area (minimized/hidden window):
+        // no new swapchain is installed and presentation must stay suspended.
+        Bool RecreateSwapchain();
 
     private:
         struct BlitUniformData {
@@ -275,6 +299,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         void QueueClearBufferPayloadForFramebuffer(const MG_State::GLState::FramebufferObject& framebuffer,
                                                   GLenum buffer, GLint drawbuffer,
                                                   const ClearAttachmentPayload& clearPayload);
+        void RecordScissoredClearBuffer(const MG_State::GLState::FramebufferObject& framebuffer,
+                                        GLenum buffer, GLint drawbuffer,
+                                        const ClearAttachmentPayload& clearPayload,
+                                        const VkClearRect& clearRect);
 
         // ---- Submission fence tracking (GL sync objects) ----
         // One record per vkQueueSubmit still in flight, in ascending submit
@@ -329,6 +357,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         void* m_platformCloseDisplay = nullptr;
         VulkanRendererConfig m_config;
         Bool m_swapchainResizeRequested = false;
+        // Presentation is suspended while the window is zero-area (minimized): the
+        // swapchain is unusable/out of date, so Present drops frames instead of
+        // submitting on a signaled fence / presenting never-acquired images.
+        Bool m_presentSuspended = false;
 
         // Vulkan objects
         Bool m_validationLayersEnabled = false;
@@ -347,8 +379,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Bool m_indexTypeUint8ExtensionEnabled = false;
         Bool m_logicOpFeatureEnabled = false;
         Bool m_multiDrawIndirectFeatureEnabled = false;
+        Bool m_samplerAnisotropyFeatureEnabled = false;
         Bool m_shaderDrawParametersExtensionEnabled = false;
         Bool m_shaderDrawParametersFeatureEnabled = false;
+        Bool m_unformattedFloatStorageImagesEnabled = false;
         // 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.
@@ -421,9 +455,64 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // Per-draw scratch buffers (clear keeps capacity) — these paths run for every
         // draw call and must not allocate.
         Vector<MG_State::GLState::ITextureObject*> m_sampledTexturesScratch;
+        Vector<MG_State::GLState::ITextureObject*> m_storageImageTexturesScratch;
         Vector<VkBuffer> m_vertexBuffersScratch;
         Vector<VkDeviceSize> m_vertexOffsetsScratch;
         Vector<VkVertexInputAttributeDescription> m_patchedAttributesScratch;
+        Vector<Float> m_vertexConversionScratch;
+        Vector<Uint8> m_vertexRepackScratch;
+
+        struct ConvertedVertexStreamKey {
+            const MG_State::GLState::BufferObject* buffer = nullptr;
+            Uint64 changeSerial = 0;
+            SizeT baseOffset = 0;
+            Uint32 sourceStride = 0;
+            DataType type = DataType::Float32;
+            Int size = 0;
+            Bool normalized = false;
+            Bool isInteger = false;
+            VertexInputStateFactory::VertexStreamConversion conversion =
+                VertexInputStateFactory::VertexStreamConversion::None;
+
+            Bool operator==(const ConvertedVertexStreamKey& other) const {
+                return buffer == other.buffer && changeSerial == other.changeSerial &&
+                       baseOffset == other.baseOffset && sourceStride == other.sourceStride &&
+                       type == other.type && size == other.size && normalized == other.normalized &&
+                       isInteger == other.isInteger && conversion == other.conversion;
+            }
+        };
+
+        struct ConvertedVertexStreamKeyHash {
+            SizeT operator()(const ConvertedVertexStreamKey& key) const {
+                SizeT hash = std::hash<const void*>{}(key.buffer);
+                auto combine = [&hash](SizeT value) {
+                    hash ^= value + static_cast<SizeT>(0x9e3779b97f4a7c15ull) + (hash << 6) + (hash >> 2);
+                };
+                combine(std::hash<Uint64>{}(key.changeSerial));
+                combine(std::hash<SizeT>{}(key.baseOffset));
+                combine(std::hash<Uint32>{}(key.sourceStride));
+                combine(std::hash<Uint32>{}(static_cast<Uint32>(key.type)));
+                combine(std::hash<Int>{}(key.size));
+                combine(std::hash<Bool>{}(key.normalized));
+                combine(std::hash<Bool>{}(key.isInteger));
+                combine(std::hash<Uint32>{}(static_cast<Uint32>(key.conversion)));
+                return hash;
+            }
+        };
+
+        struct ConvertedVertexStream {
+            BufferSlice slice;
+            // Number of source elements the cached slice covers. A draw needing a prefix of
+            // this range reuses the slice (converted streams are tightly packed); a draw
+            // needing more reconverts and replaces the entry, so per (buffer, layout) a
+            // frame converts at most the largest range any draw asked for.
+            SizeT elementCount = 0;
+            // Pins the source buffer for the frame so its heap address cannot be reused by
+            // a new BufferObject while this pointer-keyed entry is alive.
+            SharedPtr<const MG_State::GLState::BufferObject> sourcePin;
+        };
+        UnorderedMap<ConvertedVertexStreamKey, ConvertedVertexStream, ConvertedVertexStreamKeyHash>
+            m_convertedVertexStreams;
 
         void CreateInstance();
         VkResult SetupDebugMessenger();
@@ -446,10 +535,15 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             const RenderPassEntry& renderPassEntry);
         VkPipeline GetOrCreateComputePipeline(const ProgramFactory::VkProgramObject& programObj);
         void DestroyComputePipelines();
+        Bool PrepareStorageImageTextures(
+            VkCommandBuffer commandBuffer,
+            const MG_State::GLState::ProgramObject& program,
+            const ProgramFactory::VkProgramObject& programObj);
 
         Bool UploadAndBindVertexBuffers(VkCommandBuffer commandBuffer, const MG_State::GLState::VertexArrayObject& vao,
                                         const ProgramFactory::VkProgramObject& programObj,
-                                        const DrawCmdParam& drawParams);
+                                        const DrawCmdParam& drawParams,
+                                        const IndexBufferView* pIndexBufferView);
         Bool UploadAndBindIndexBuffer(FrameContext::FrameData& frame,
                                      const MG_State::GLState::VertexArrayObject& vao,
                                       const IndexBufferView* pIndexBufferView = nullptr);
@@ -467,6 +561,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                                    GLenum filter);
         Bool MaterializePendingClearForTexture(VkCommandBuffer commandBuffer,
                                                MG_State::GLState::ITextureObject& texture);
+        Bool MaterializePendingClearForRenderbuffer(
+            VkCommandBuffer commandBuffer,
+            const SharedPtr<MG_State::GLState::RenderbufferObject>& renderbuffer);
         VkPipeline GetOrCreateBlitPipeline(const RenderPassEntry& renderPassEntry);
         Bool GenerateDepthMipmapWithShader(FrameContext::FrameData& frame,
                                            MG_State::GLState::ITextureObject& texture,

MobileGL/MG_Benchmark/Buffer/CMakeLists.txt

@@ -16,4 +16,5 @@ target_link_libraries(
         ${LINK_LIBRARIES}
 )
 
-add_test(NAME BufferBench COMMAND BufferBench --benchmark_counters_tabular=true)
+add_test(NAME BufferBench COMMAND BufferBench --benchmark_counters_tabular=true)
+set_tests_properties(BufferBench PROPERTIES LABELS benchmark)

MobileGL/MG_Benchmark/CMakeLists.txt

@@ -38,6 +38,7 @@ target_link_libraries(
 )
 
 add_test(NAME SanityBench COMMAND SanityBench --benchmark_counters_tabular=true)
+set_tests_properties(SanityBench PROPERTIES LABELS benchmark)
 
 add_subdirectory(Program)
 add_subdirectory(Buffer)

MobileGL/MG_Benchmark/Program/CMakeLists.txt

@@ -16,4 +16,5 @@ target_link_libraries(
         ${LINK_LIBRARIES}
 )
 
-add_test(NAME ProgramBench COMMAND ProgramBench --benchmark_counters_tabular=true)
+add_test(NAME ProgramBench COMMAND ProgramBench --benchmark_counters_tabular=true)
+set_tests_properties(ProgramBench PROPERTIES LABELS benchmark)

MobileGL/MG_Impl/EGLImpl/EGLImpl.cpp

@@ -8,6 +8,7 @@
 
 #include "EGLImpl.h"
 #include "../GetProcAddress.h"
+#include <Init.h>
 #include <MG_Backend/BackendObjects.h>
 #include <MG_State/EGLState/Core.h>
 #include <mutex>
@@ -25,6 +26,17 @@ namespace MobileGL::MG_Impl::EGLImpl {
             return MG_State::pEGLContext.get();
         }
 
+        // Entry points that can legitimately be an application's FIRST EGL
+        // call (display/proc-address/string queries) lazily bring MobileGL
+        // up here, so the library needs no static constructor and can
+        // re-initialize after the last eglTerminate tore everything down.
+        // Teardown-ish entry points keep using GetState() and fail benignly
+        // when MobileGL is not initialized.
+        EGLStateContext* GetStateEnsureInitialized() {
+            MobileGL::EnsureInitialized();
+            return GetState();
+        }
+
         MG_Backend::BackendObject* GetBackendObject(EGLStateContext* state) {
             auto* backendObject = MG_Backend::pActiveBackendObject.get();
             if (!backendObject && state) {
@@ -49,6 +61,8 @@ namespace MobileGL::MG_Impl::EGLImpl {
             return MG_Backend::WindowBackend::Android;
 #elif defined(__APPLE__)
             return MG_Backend::WindowBackend::MetalLayer;
+#elif defined(_WIN32)
+            return MG_Backend::WindowBackend::Win32;
 #elif defined(__linux__)
             return MG_Backend::WindowBackend::X11;
 #else
@@ -187,7 +201,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
     }
 
     EGLBoolean Initialize(EGLDisplay dpy, EGLint* major, EGLint* minor) {
-        auto* state = GetState();
+        auto* state = GetStateEnsureInitialized();
         if (!state) {
             return EGL_FALSE;
         }
@@ -208,7 +222,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
     }
 
     EGLDisplay GetDisplay(NativeDisplayType display) {
-        auto* state = GetState();
+        auto* state = GetStateEnsureInitialized();
         if (!state) {
             return EGL_NO_DISPLAY;
         }
@@ -313,6 +327,14 @@ namespace MobileGL::MG_Impl::EGLImpl {
         if (auto* backendObject = MG_Backend::pActiveBackendObject.get()) {
             backendObject->ReleaseEGLResources();
         }
+        // The last initialized display is gone and nothing is current on any
+        // thread: tear the whole library down deterministically inside the
+        // EGL lifecycle (backend, GL/EGL state, glslang). A later EGL call
+        // re-initializes lazily via GetStateEnsureInitialized(); process exit
+        // then has nothing left to destroy.
+        if (!state->HasAnyInitializedDisplay() && !state->HasAnyCurrentContext()) {
+            MobileGL::Destroy();
+        }
         return EGL_TRUE;
     }
 
@@ -345,7 +367,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
     }
 
     EGLBoolean BindAPI(EGLenum api) {
-        auto* state = GetState();
+        auto* state = GetStateEnsureInitialized();
         if (!state) {
             return EGL_FALSE;
         }
@@ -378,7 +400,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
     }
 
     char const* QueryString(EGLDisplay display, EGLint name) {
-        auto* state = GetState();
+        auto* state = GetStateEnsureInitialized();
         if (!state) {
             return nullptr;
         }
@@ -641,7 +663,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
     EGLDisplay GetPlatformDisplay(EGLenum platform, void* native_display, const EGLAttrib* attrib_list) {
         (void)attrib_list;
 
-        auto* state = GetState();
+        auto* state = GetStateEnsureInitialized();
         if (!state) {
             return EGL_NO_DISPLAY;
         }
@@ -737,6 +759,7 @@ namespace MobileGL::MG_Impl::EGLImpl {
         if (!name) {
             return nullptr;
         }
+        MobileGL::EnsureInitialized();
 
         MGLOG_D("eglGetProcAddress(%s)", name);
         void* proc = MG_Impl::GetProcAddress(name);

MobileGL/MG_Impl/GLImpl/Buffer/GL_Buffer.cpp

@@ -441,7 +441,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         for (SizeT i = 0; i < static_cast<SizeT>(n); ++i) {
             Uint bufferName = buffers[i];
             if (bufferName == 0) continue;
-            if (!BufferImpl::ValidateBufferName(bufferName, true)) continue;
+            // GL 3.3 core 2.9: names that do not correspond to an existing buffer are silently
+            // ignored here, so probe with the non-recording query - the shared validator would
+            // record INVALID_OPERATION, which is only correct on the bind path.
+            if (!MG_State::pGLContext->ValidateBufferName(bufferName)) continue;
             MG_State::pGLContext->MarkBufferObjectForDeletion(bufferName);
         }
     }

MobileGL/MG_Impl/GLImpl/Drawing/GL_Drawing.cpp

@@ -67,7 +67,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
 
         const auto& vao = MG_State::pGLContext->GetBoundVertexArray();
-        if (MG_State::pEGLContext->IsCurrentContextOpenGLCoreProfile() && vao && vao->GetExternalIndex() == 0) {
+        if (vao && vao->GetExternalIndex() == 0 && !MG_State::IsRelaxedSemanticsActive()) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidOperation,
                 MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,

MobileGL/MG_Impl/GLImpl/Exporting/Definitions.cpp

@@ -295,7 +295,13 @@ DECLARE_GL_FUNCTION_HEAD(void, VertexAttribDivisor, GLuint index, GLuint divisor
 DECLARE_GL_FUNCTION_STUB_HEAD(void, BindTransformFeedback, GLenum target, GLuint id) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, BindTransformFeedback, target, id)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, DeleteTransformFeedbacks, GLsizei n, const GLuint* ids) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, DeleteTransformFeedbacks, n, ids)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, GenTransformFeedbacks, GLsizei n, GLuint* ids) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, GenTransformFeedbacks, n, ids)
-DECLARE_GL_FUNCTION_STUB_HEAD(GLboolean, IsTransformFeedback, GLuint id) DECLARE_GL_FUNCTION_STUB_END(GLboolean, IsTransformFeedback, id)
+// Transform feedback objects are not implemented, so no name is ever a live object. The shared
+// stub returns (type)1, telling a probing caller that every id it invents already exists; GL_FALSE
+// is both truthful and what the spec requires for a name that was never generated.
+MOBILEGL_GL_API GLboolean glIsTransformFeedback(GLuint id) {
+    MGLOG_W("Stub function: %s(...)", __FUNCTION__);
+    return GL_FALSE;
+}
 DECLARE_GL_FUNCTION_STUB_HEAD(void, PauseTransformFeedback) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, PauseTransformFeedback)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, ResumeTransformFeedback) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ResumeTransformFeedback)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, GetProgramBinary, GLuint program, GLsizei bufSize, GLsizei* length, GLenum* binaryFormat, void* binary) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, GetProgramBinary, program, bufSize, length, binaryFormat, binary)
@@ -418,7 +424,7 @@ DECLARE_GL_FUNCTION_HEAD(void, DrawRangeElementsBaseVertex, GLenum mode, GLuint
 DECLARE_GL_FUNCTION_HEAD(void, DrawElementsInstancedBaseVertex, GLenum mode, GLsizei count, GLenum type, const void* indices, GLsizei instancecount, GLint basevertex) DECLARE_GL_FUNCTION_END_NO_RETURN(void, DrawElementsInstancedBaseVertex, mode, count, type, indices, instancecount, basevertex)
 DECLARE_GL_FUNCTION_HEAD(void, FramebufferTexture, GLenum target, GLenum attachment, GLuint texture, GLint level) DECLARE_GL_FUNCTION_END_NO_RETURN(void, FramebufferTexture, target, attachment, texture, level)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, PrimitiveBoundingBox, GLfloat minX, GLfloat minY, GLfloat minZ, GLfloat minW, GLfloat maxX, GLfloat maxY, GLfloat maxZ, GLfloat maxW) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, PrimitiveBoundingBox, minX, minY, minZ, minW, maxX, maxY, maxZ, maxW)
-DECLARE_GL_FUNCTION_STUB_HEAD(GLenum, GetGraphicsResetStatus) DECLARE_GL_FUNCTION_STUB_END(GLenum, GetGraphicsResetStatus)
+DECLARE_GL_FUNCTION_HEAD(GLenum, GetGraphicsResetStatus) DECLARE_GL_FUNCTION_END(GLenum, GetGraphicsResetStatus)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, ReadnPixels, GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, GLsizei bufSize, void* data) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ReadnPixels, x, y, width, height, format, type, bufSize, data)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, GetnUniformfv, GLuint program, GLint location, GLsizei bufSize, GLfloat* params) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, GetnUniformfv, program, location, bufSize, params)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, GetnUniformiv, GLuint program, GLint location, GLsizei bufSize, GLint* params) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, GetnUniformiv, program, location, bufSize, params)
@@ -998,8 +1004,8 @@ DECLARE_GL_FUNCTION_HEAD(void, ShaderStorageBlockBinding, GLuint program, GLuint
 DECLARE_GL_FUNCTION_STUB_HEAD(void, TextureView, GLuint texture, GLenum target, GLuint origtexture, GLenum internalformat, GLuint minlevel, GLuint numlevels, GLuint minlayer, GLuint numlayers) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, TextureView, texture, target, origtexture, internalformat, minlevel, numlevels, minlayer, numlayers)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, VertexAttribLFormat, GLuint attribindex, GLint size, GLenum type, GLuint relativeoffset) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, VertexAttribLFormat, attribindex, size, type, relativeoffset)
 DECLARE_GL_FUNCTION_HEAD(void, BufferStorage, GLenum target, GLsizeiptr size, const void* data, GLbitfield flags) DECLARE_GL_FUNCTION_END_NO_RETURN(void, BufferStorage, target, size, data, flags)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, ClearTexImage, GLuint texture, GLint level, GLenum format, GLenum type, const void* data) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ClearTexImage, texture, level, format, type, data)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, ClearTexSubImage, GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint zoffset, GLsizei width, GLsizei height, GLsizei depth, GLenum format, GLenum type, const void* data) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ClearTexSubImage, texture, level, xoffset, yoffset, zoffset, width, height, depth, format, type, data)
+DECLARE_GL_FUNCTION_HEAD(void, ClearTexImage, GLuint texture, GLint level, GLenum format, GLenum type, const void* data) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ClearTexImage, texture, level, format, type, data)
+DECLARE_GL_FUNCTION_HEAD(void, ClearTexSubImage, GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint zoffset, GLsizei width, GLsizei height, GLsizei depth, GLenum format, GLenum type, const void* data) DECLARE_GL_FUNCTION_END_NO_RETURN(void, ClearTexSubImage, texture, level, xoffset, yoffset, zoffset, width, height, depth, format, type, data)
 DECLARE_GL_FUNCTION_HEAD(void, BindBuffersBase, GLenum target, GLuint first, GLsizei count, const GLuint* buffers) DECLARE_GL_FUNCTION_END_NO_RETURN(void, BindBuffersBase, target, first, count, buffers)
 DECLARE_GL_FUNCTION_HEAD(void, BindBuffersRange, GLenum target, GLuint first, GLsizei count, const GLuint* buffers, const GLintptr* offsets, const GLsizeiptr* sizes) DECLARE_GL_FUNCTION_END_NO_RETURN(void, BindBuffersRange, target, first, count, buffers, offsets, sizes)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, BindTextures, GLuint first, GLsizei count, const GLuint* textures) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, BindTextures, first, count, textures)
@@ -1063,7 +1069,7 @@ DECLARE_GL_FUNCTION_STUB_HEAD(void, CompressedTextureSubImage1D, GLuint texture,
 DECLARE_GL_FUNCTION_STUB_HEAD(void, CompressedTextureSubImage2D, GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLsizei imageSize, const void* data) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, CompressedTextureSubImage2D, texture, level, xoffset, yoffset, width, height, format, imageSize, data)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, CompressedTextureSubImage3D, GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint zoffset, GLsizei width, GLsizei height, GLsizei depth, GLenum format, GLsizei imageSize, const void* data) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, CompressedTextureSubImage3D, texture, level, xoffset, yoffset, zoffset, width, height, depth, format, imageSize, data)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, CopyTextureSubImage1D, GLuint texture, GLint level, GLint xoffset, GLint x, GLint y, GLsizei width) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, CopyTextureSubImage1D, texture, level, xoffset, x, y, width)
-DECLARE_GL_FUNCTION_STUB_HEAD(void, CopyTextureSubImage2D, GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width, GLsizei height) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, CopyTextureSubImage2D, texture, level, xoffset, yoffset, x, y, width, height)
+DECLARE_GL_FUNCTION_HEAD(void, CopyTextureSubImage2D, GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width, GLsizei height) DECLARE_GL_FUNCTION_END_NO_RETURN(void, CopyTextureSubImage2D, texture, level, xoffset, yoffset, x, y, width, height)
 DECLARE_GL_FUNCTION_STUB_HEAD(void, CopyTextureSubImage3D, GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint zoffset, GLint x, GLint y, GLsizei width, GLsizei height) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, CopyTextureSubImage3D, texture, level, xoffset, yoffset, zoffset, x, y, width, height)
 DECLARE_GL_FUNCTION_HEAD(void, TextureParameterf, GLuint texture, GLenum pname, GLfloat param) DECLARE_GL_FUNCTION_END_NO_RETURN(void, TextureParameterf, texture, pname, param)
 DECLARE_GL_FUNCTION_HEAD(void, TextureParameterfv, GLuint texture, GLenum pname, const GLfloat* param) DECLARE_GL_FUNCTION_END_NO_RETURN(void, TextureParameterfv, texture, pname, param)
@@ -2583,7 +2589,10 @@ DECLARE_GL_FUNCTION_STUB_HEAD(void, TransformFeedbackStreamAttribsNV, GLsizei co
 DECLARE_GL_FUNCTION_STUB_HEAD(void, BindTransformFeedbackNV, GLenum target, GLuint id) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, BindTransformFeedbackNV, target, id)
 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)
-DECLARE_GL_FUNCTION_STUB_HEAD(GLboolean, IsTransformFeedbackNV, GLuint id) DECLARE_GL_FUNCTION_STUB_END(GLboolean, IsTransformFeedbackNV, id)
+MOBILEGL_GL_API GLboolean glIsTransformFeedbackNV(GLuint id) {
+    MGLOG_W("Stub function: %s(...)", __FUNCTION__);
+    return GL_FALSE;
+}
 DECLARE_GL_FUNCTION_STUB_HEAD(void, PauseTransformFeedbackNV, void) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, PauseTransformFeedbackNV, )
 DECLARE_GL_FUNCTION_STUB_HEAD(void, ResumeTransformFeedbackNV, void) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, ResumeTransformFeedbackNV, )
 DECLARE_GL_FUNCTION_STUB_HEAD(void, DrawTransformFeedbackNV, GLenum mode, GLuint id) DECLARE_GL_FUNCTION_STUB_END_NO_RETURN(void, DrawTransformFeedbackNV, mode, id)

MobileGL/MG_Impl/GLImpl/Framebuffer/GL_Framebuffer.cpp

@@ -60,6 +60,87 @@ namespace MobileGL::MG_Impl::GLImpl {
             return false;
         }
 
+        // Whether the backend can actually attach this color format to a framebuffer. Preferred
+        // source of truth is the backend's probed format-capability cache (real glCheckFramebufferStatus
+        // probes, so extensions like EXT_render_snorm are respected). Formats a probe-less backend
+        // cannot answer for fall back to a conservative static list of formats no ES driver renders to:
+        // shared-exponent, SNORM, three-channel norm16/float32/sRGB and three-channel integer formats.
+        // Desktop GL treats those as texture-only too (not in the GL 3.3 required-renderable list), so
+        // reporting GL_FRAMEBUFFER_UNSUPPORTED for them is legal.
+        Bool IsColorInternalFormatRenderable(TextureInternalFormat format) {
+            const SizeT formatIndex = static_cast<SizeT>(format);
+            if (MG_Backend::pActiveBackendObject && formatIndex < MG_Backend::kFormatCapabilityFormatCount) {
+                const auto& cache = MG_Backend::pActiveBackendObject->GetFormatCapabilities();
+                const SizeT sentinelFormat = static_cast<SizeT>(TextureInternalFormat::RGBA8);
+                Bool cachePopulated = false;
+                for (SizeT targetIndex = 0; targetIndex < MG_Backend::kFormatCapabilityTargetCount && !cachePopulated;
+                     ++targetIndex) {
+                    cachePopulated = MG_Backend::HasFormatCapability(cache.FullCaps[targetIndex][sentinelFormat],
+                                                                     MG_Backend::FormatCapability::Creatable);
+                }
+                if (cachePopulated) {
+                    for (SizeT targetIndex = 0; targetIndex < MG_Backend::kFormatCapabilityTargetCount;
+                         ++targetIndex) {
+                        if (MG_Backend::HasFormatCapability(cache.FullCaps[targetIndex][formatIndex],
+                                                            MG_Backend::FormatCapability::FramebufferRenderable) ||
+                            MG_Backend::HasFormatCapability(cache.CaveatCaps[targetIndex][formatIndex],
+                                                            MG_Backend::FormatCapability::FramebufferRenderable)) {
+                            return true;
+                        }
+                    }
+                    return false;
+                }
+            }
+            switch (format) {
+            case TextureInternalFormat::RGB9E5:
+            case TextureInternalFormat::R8Snorm:
+            case TextureInternalFormat::RG8Snorm:
+            case TextureInternalFormat::RGB8Snorm:
+            case TextureInternalFormat::RGBA8Snorm:
+            case TextureInternalFormat::R16Snorm:
+            case TextureInternalFormat::RG16Snorm:
+            case TextureInternalFormat::RGB16Snorm:
+            case TextureInternalFormat::RGBA16Snorm:
+            case TextureInternalFormat::RGB16:
+            case TextureInternalFormat::RGB10: // stored as RGB16
+            case TextureInternalFormat::RGB12: // stored as RGB16
+            case TextureInternalFormat::RGB16F:
+            case TextureInternalFormat::RGB32F:
+            case TextureInternalFormat::RGB8I:
+            case TextureInternalFormat::RGB8UI:
+            case TextureInternalFormat::RGB16I:
+            case TextureInternalFormat::RGB16UI:
+            case TextureInternalFormat::RGB32I:
+            case TextureInternalFormat::RGB32UI:
+            case TextureInternalFormat::SRGB8:
+                return false;
+            default:
+                return true;
+            }
+        }
+
+        Bool HasNonRenderableColorAttachment(const MG_State::GLState::FramebufferObject& framebufferObject) {
+            const auto& attachments = framebufferObject.GetAllAttachmentObjects();
+            for (SizeT i = 0; i < attachments.size(); ++i) {
+                const auto type = static_cast<FramebufferAttachmentType>(i);
+                if (type < FramebufferAttachmentType::Color0 || type > FramebufferAttachmentType::Color31) {
+                    continue;
+                }
+                const auto& attachment = attachments[i];
+                if (!attachment.IsValid()) continue;
+                TextureInternalFormat format = TextureInternalFormat::Unknown;
+                if (attachment.IsTexture() && attachment.GetTexture()) {
+                    format = attachment.GetTexture()->GetFormat();
+                } else if (attachment.IsRenderbuffer() && attachment.GetRenderbuffer()) {
+                    format = attachment.GetRenderbuffer()->GetInternalFormat();
+                }
+                if (format != TextureInternalFormat::Unknown && !IsColorInternalFormatRenderable(format)) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
         void RecordUnsupportedFramebufferTextureAttachmentError(const char* functionName, const char* detail) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidOperation,
@@ -556,6 +637,62 @@ namespace MobileGL::MG_Impl::GLImpl {
         return framebufferObject;
     }
 
+    // Attaches a single layer/slice of a 3D or array texture. The attachment model stores the layer
+    // index; the DirectGLES backend attaches it with glFramebufferTextureLayer.
+    static void AttachFramebufferTextureLayer(const char* functionName, GLenum target, GLenum attachment,
+                                              GLuint texture, GLint level, GLint layer,
+                                              TextureUploadTarget textureUploadTarget) {
+        if (target == GL_FRAMEBUFFER) {
+            target = GL_DRAW_FRAMEBUFFER;
+        }
+        if (attachment == GL_DEPTH_STENCIL_ATTACHMENT) {
+            AttachFramebufferTextureLayer(functionName, target, GL_DEPTH_ATTACHMENT, texture, level, layer,
+                                          textureUploadTarget);
+            AttachFramebufferTextureLayer(functionName, target, GL_STENCIL_ATTACHMENT, texture, level, layer,
+                                          textureUploadTarget);
+            return;
+        }
+
+        const FramebufferAttachmentType attachmentType = MG_Util::ConvertGLEnumToFramebufferAttachmentType(attachment);
+        const FramebufferTarget framebufferTarget = MG_Util::ConvertGLEnumToFramebufferTarget(target);
+        if (!FramebufferImpl::ValidateFramebufferAttachmentType(attachmentType)) return;
+        if (!FramebufferImpl::ValidateFramebufferTarget(framebufferTarget)) return;
+        if (!TextureImpl::ValidateTextureName(texture, true)) return;
+
+        auto& bindingSlot = MG_State::pGLContext->GetFramebufferBindingSlot(framebufferTarget);
+        auto& framebufferObject = bindingSlot.GetBoundObject();
+        if (!framebufferObject) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
+                                             "Framebuffer target is bound to no framebuffer object."));
+            return;
+        }
+
+        if (texture == 0) {
+            framebufferObject->Detach(attachmentType);
+            return;
+        }
+
+        auto& textureObject = MG_State::pGLContext->GetTextureObject(texture);
+        if (!textureObject) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName,
+                                             std::format("Texture object {} is not valid.", texture)));
+            return;
+        }
+        if (layer < 0) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidValue,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", functionName, "Layer must be non-negative."));
+            return;
+        }
+
+        framebufferObject->AttachTexture(attachmentType, textureObject, textureUploadTarget, level, layer,
+                                         /*layered=*/false);
+    }
+
     void FramebufferTextureLayer_State(GLenum target, GLenum attachment, GLuint texture, GLint level, GLint layer) {
         if (texture == 0) {
             const TextureUploadTarget detachTarget = TextureUploadTarget::Texture2D;
@@ -563,10 +700,31 @@ namespace MobileGL::MG_Impl::GLImpl {
             return;
         }
 
-        static_cast<void>(layer);
-        RecordUnsupportedFramebufferTextureAttachmentError(
-            __func__,
-            "Layered framebuffer texture attachments are not represented by the current framebuffer attachment model.");
+        auto& textureObject = MG_State::pGLContext->GetTextureObject(texture);
+        if (!textureObject) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                             std::format("Texture object {} is not valid.", texture)));
+            return;
+        }
+        TextureUploadTarget textureUploadTarget = TextureUploadTarget::Unknown;
+        switch (textureObject->GetTarget()) {
+        case TextureTarget::Texture3D:
+            textureUploadTarget = TextureUploadTarget::Texture3D;
+            break;
+        case TextureTarget::Texture2DArray:
+            textureUploadTarget = TextureUploadTarget::Texture2DArray;
+            break;
+        case TextureTarget::Texture2DMultisampleArray:
+            textureUploadTarget = TextureUploadTarget::Texture2DMultisampleArray;
+            break;
+        default:
+            RecordUnsupportedFramebufferTextureAttachmentError(
+                __func__, "FramebufferTextureLayer requires a 3D, 2D array or 2D multisample array texture.");
+            return;
+        }
+        AttachFramebufferTextureLayer(__func__, target, attachment, texture, level, layer, textureUploadTarget);
     }
 
     void FramebufferTexture3D_State(GLenum target, GLenum attachment, GLenum textarget, GLuint texture, GLint level,
@@ -578,10 +736,15 @@ namespace MobileGL::MG_Impl::GLImpl {
             return;
         }
 
-        static_cast<void>(zoffset);
-        RecordUnsupportedFramebufferTextureAttachmentError(
-            __func__,
-            "3D framebuffer texture slice attachments are not represented by the current framebuffer attachment model.");
+        if (textarget != GL_TEXTURE_3D) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidEnum,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                             "FramebufferTexture3D requires GL_TEXTURE_3D."));
+            return;
+        }
+        AttachFramebufferTextureLayer(__func__, target, attachment, texture, level, zoffset,
+                                      TextureUploadTarget::Texture3D);
     }
 
     void FramebufferTexture2D_State(GLenum target, GLenum attachment, GLenum textarget, GLuint texture, GLint level) {
@@ -1014,7 +1177,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             auto& bindingSlot = MG_State::pGLContext->GetFramebufferBindingSlot(FramebufferTarget::Draw);
             auto& fbo = bindingSlot.GetBoundObject();
             const bool isDefaultFBO = (fbo == FramebufferImpl::pDefaultFramebufferInfo->defaultFBO);
-            static GLenum bufs[] = {buf};
+            const GLenum bufs[] = {buf};
             DrawBuffersForFramebuffer_State(fbo, isDefaultFBO, 1, bufs, true);
         }
     }
@@ -1201,7 +1364,9 @@ namespace MobileGL::MG_Impl::GLImpl {
         for (SizeT i = 0; i < static_cast<SizeT>(n); ++i) {
             Uint bufferName = renderbuffers[i];
             if (bufferName == 0) continue;
-            if (!FramebufferImpl::ValidateRenderbufferName(bufferName)) continue;
+            // GL 3.3 core 4.4.2: unknown names are silently ignored on delete; the shared bind-path
+            // validator would record INVALID_OPERATION instead.
+            if (!MG_State::pGLContext->ValidateRenderbufferName(bufferName)) continue;
             MG_State::pGLContext->MarkRenderbufferObjectForDeletion(bufferName);
         }
     }
@@ -1224,7 +1389,9 @@ namespace MobileGL::MG_Impl::GLImpl {
         for (SizeT i = 0; i < static_cast<SizeT>(n); ++i) {
             Uint bufferName = framebuffers[i];
             if (bufferName == 0) continue;
-            if (!FramebufferImpl::ValidateFramebufferName(bufferName)) continue;
+            // GL 3.3 core 4.4.1: unknown names are silently ignored on delete; the shared bind-path
+            // validator would record INVALID_OPERATION instead.
+            if (!MG_State::pGLContext->ValidateFramebufferName(bufferName)) continue;
             MG_State::pGLContext->MarkFramebufferObjectForDeletion(bufferName);
         }
     }
@@ -1252,6 +1419,9 @@ namespace MobileGL::MG_Impl::GLImpl {
                 GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT :
                 GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT;
         }
+        if (HasNonRenderableColorAttachment(*framebufferObject)) {
+            return GL_FRAMEBUFFER_UNSUPPORTED;
+        }
         if (IsActiveBackendDirectVulkan() &&
             IsUnsupportedFramebufferForDirectVulkan(*framebufferObject)) {
             return GL_FRAMEBUFFER_UNSUPPORTED;
@@ -1277,6 +1447,9 @@ namespace MobileGL::MG_Impl::GLImpl {
                 GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT :
                 GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT;
         }
+        if (HasNonRenderableColorAttachment(*framebufferObject)) {
+            return GL_FRAMEBUFFER_UNSUPPORTED;
+        }
         if (IsActiveBackendDirectVulkan() &&
             IsUnsupportedFramebufferForDirectVulkan(*framebufferObject)) {
             return GL_FRAMEBUFFER_UNSUPPORTED;
@@ -1626,8 +1799,8 @@ namespace MobileGL::MG_Impl::GLImpl {
             return false;
         }
 
-        // Check framebuffer completeness
-        if (!framebufferObject->CheckCompleteness()) {
+        // Check framebuffer completeness (including formats the ES pipeline cannot attach)
+        if (!framebufferObject->CheckCompleteness() || HasNonRenderableColorAttachment(*framebufferObject)) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidFramebufferOperation,
                 MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "ReadPixels_State", "Framebuffer is incomplete"));
@@ -1679,6 +1852,40 @@ namespace MobileGL::MG_Impl::GLImpl {
                                                  "No color buffer for color format"));
                 return false;
             }
+
+            // GL 3.3 section 4.3.1: GL_INVALID_OPERATION if format is an integer format and the read
+            // buffer is not an integer format, or vice versa (GL CTS packed_pixels expects the error
+            // for every *_INTEGER readback from a normalized attachment).
+            const auto& readAttachment = framebufferObject->GetAttachment(readBuffer);
+            TextureInternalFormat attachmentFormat = TextureInternalFormat::Unknown;
+            if (readAttachment.IsTexture() && readAttachment.GetTexture()) {
+                attachmentFormat = readAttachment.GetTexture()->GetFormat();
+            } else if (readAttachment.IsRenderbuffer() && readAttachment.GetRenderbuffer()) {
+                attachmentFormat = readAttachment.GetRenderbuffer()->GetInternalFormat();
+            }
+            if (attachmentFormat != TextureInternalFormat::Unknown &&
+                TextureImpl::IsIntegerColorInputFormat(textureInputFormat) !=
+                    TextureImpl::IsIntegerColorInternalFormat(attachmentFormat)) {
+                MG_State::pGLContext->RecordError(
+                    ErrorCode::InvalidOperation,
+                    MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "ReadPixels_State",
+                                                 "Integer-ness of format does not match the read buffer"));
+                return false;
+            }
+        }
+
+        // Packed-type/format pairing (GL CTS packed_pixels: e.g. GL_RED with GL_UNSIGNED_SHORT_5_6_5 must
+        // raise an error instead of reaching the backend). Shared with the TexImage/GetTexImage validators;
+        // runs after the depth-stencil branch above so DEPTH_STENCIL with a wrong type keeps GL_INVALID_ENUM.
+        if (!TextureImpl::ValidateClientFormatTypePairing(textureInputFormat, texturePixelDataType)) {
+            return false;
+        }
+
+        // Packed-type/format pairing (GL CTS packed_pixels: e.g. GL_RED with GL_UNSIGNED_SHORT_5_6_5 must
+        // raise an error instead of reaching the backend). Shared with the TexImage/GetTexImage validators;
+        // runs after the depth-stencil branch above so DEPTH_STENCIL with a wrong type keeps GL_INVALID_ENUM.
+        if (!TextureImpl::ValidateClientFormatTypePairing(textureInputFormat, texturePixelDataType)) {
+            return false;
         }
 
         // Check PBO state
@@ -1937,6 +2144,7 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     namespace FramebufferImpl {
-        UniquePtr<DefaultFramebufferInfo> pDefaultFramebufferInfo;
+        // Leak-at-exit storage; see GlobalObjects.cpp.
+        UniquePtr<DefaultFramebufferInfo>& pDefaultFramebufferInfo = *new UniquePtr<DefaultFramebufferInfo>();
     } // namespace FramebufferImpl
 } // namespace MobileGL::MG_Impl::GLImpl

MobileGL/MG_Impl/GLImpl/Framebuffer/GL_Framebuffer.h

@@ -78,6 +78,6 @@ namespace MobileGL::MG_Impl::GLImpl {
             SharedPtr<MG_State::GLState::ITextureObject> stencilAttachment;
         };
 
-        extern UniquePtr<DefaultFramebufferInfo> pDefaultFramebufferInfo;
+        extern UniquePtr<DefaultFramebufferInfo>& pDefaultFramebufferInfo;
     } // namespace FramebufferImpl
 } // namespace MobileGL::MG_Impl::GLImpl

MobileGL/MG_Impl/GLImpl/Framebuffer/Validators.cpp

@@ -76,7 +76,13 @@ namespace MobileGL::MG_Impl::GLImpl::FramebufferImpl {
     }
 
     Bool ValidateRenderbufferName(Uint index, Bool allowZero) {
-        if (index == 0 && !allowZero) {
+        if (index == 0) {
+            // Zero is never a GenRenderbuffers name, so it must not reach the name-table lookup
+            // below: where it is allowed (glBindRenderbuffer / FramebufferRenderbuffer detach) it
+            // means "unbind", and looking it up would record a bogus INVALID_OPERATION - GL CTS's
+            // per-case state reset calls glBindRenderbuffer(GL_RENDERBUFFER, 0) after every case.
+            if (allowZero) return true;
+
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidValue,
                 MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl/FramebufferImpl", "ValidateRenderbufferName",

MobileGL/MG_Impl/GLImpl/Getter/GL_Getter.cpp

@@ -529,6 +529,13 @@ namespace MobileGL::MG_Impl::GLImpl {
             params[1] = dynamicParameters.AliasedLineWidthRangeMax;
             return;
         }
+        case GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT: {
+            // EXT_texture_filter_anisotropic queries this as a float; the integer path below widens
+            // from here, so this case is the authoritative one.
+            const auto& dynamicParameters = MG_Backend::pActiveBackendObject->GetDynamicParameters();
+            params[0] = dynamicParameters.MaxTextureMaxAnisotropy;
+            return;
+        }
         case GL_ALIASED_POINT_SIZE_RANGE:
         case GL_POINT_SIZE_RANGE: {
             const auto& dynamicParameters = MG_Backend::pActiveBackendObject->GetDynamicParameters();
@@ -1168,10 +1175,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = kFrontendMaxFragmentInputComponents;
             return;
         case GL_MAX_FRAGMENT_IMAGE_UNIFORMS:
-            // TODO: Track per-stage image uniform limits separately instead of reusing the compute/backend stage cap.
             *params = MG_Backend::pActiveBackendObject
-                          ? MG_Backend::pActiveBackendObject->GetDynamicParameters().MaxComputeImageUniforms
-                          : MG_Backend::DynamicBackendParameters{}.MaxComputeImageUniforms;
+                          ? MG_Backend::pActiveBackendObject->GetDynamicParameters().MaxFragmentImageUniforms
+                          : MG_Backend::DynamicBackendParameters{}.MaxFragmentImageUniforms;
             return;
         case GL_MAX_FRAGMENT_UNIFORM_COMPONENTS:
             *params = kFrontendMaxFragmentUniformComponents;
@@ -1201,7 +1207,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = kFrontendMaxGeometryTextureImageUnits;
             return;
         case GL_MAX_GEOMETRY_IMAGE_UNIFORMS:
-            *params = 0;
+            *params = MG_Backend::pActiveBackendObject
+                          ? MG_Backend::pActiveBackendObject->GetDynamicParameters().MaxGeometryImageUniforms
+                          : MG_Backend::DynamicBackendParameters{}.MaxGeometryImageUniforms;
             return;
         case GL_MAX_GEOMETRY_TOTAL_OUTPUT_COMPONENTS:
             *params = kFrontendMaxGeometryTotalOutputComponents;
@@ -1270,7 +1278,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = kFrontendMaxVertexAtomicCounters;
             return;
         case GL_MAX_VERTEX_IMAGE_UNIFORMS:
-            *params = 0;
+            *params = MG_Backend::pActiveBackendObject
+                          ? MG_Backend::pActiveBackendObject->GetDynamicParameters().MaxVertexImageUniforms
+                          : MG_Backend::DynamicBackendParameters{}.MaxVertexImageUniforms;
             return;
         case GL_MAX_VERTEX_SHADER_STORAGE_BLOCKS:
             *params = 16; // TODO
@@ -1727,7 +1737,11 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = 1024 * 1024; // TODO
             return;
         case GL_CONTEXT_PROFILE_MASK:
-            *params = GL_CONTEXT_CORE_PROFILE_BIT;
+            // Reports the requested context profile (EGL defaults 3.x contexts to core);
+            // MOBILEGL_RELAXED_SEMANTICS loosens behavior without changing the identity.
+            *params = MG_State::pEGLContext && MG_State::pEGLContext->IsCurrentContextOpenGLCompatibilityProfile()
+                          ? GL_CONTEXT_COMPATIBILITY_PROFILE_BIT
+                          : GL_CONTEXT_CORE_PROFILE_BIT;
             return;
         default:
             break;
@@ -1894,7 +1908,13 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = dynamicParameters.MaxTextureSize;
             break;
         case GL_MAX_UNIFORM_BUFFER_BINDINGS:
-            *params = std::max(dynamicParameters.MaxUniformBufferBindings, kFrontendMinUniformBufferBindings);
+            // Never advertise more bindings than the state layer's indexed-binding array can track
+            // (BufferState::BufferBindingPointCount): glBindBufferBase rejects indices past that
+            // capacity, and the GL CTS per-case state reset calls glBindBufferBase on every
+            // advertised index and expects no error. The floor equals the GL 3.3 core minimum
+            // (36), so the clamp never under-advertises.
+            *params = std::clamp(dynamicParameters.MaxUniformBufferBindings, kFrontendMinUniformBufferBindings,
+                                 static_cast<GLint>(MG_State::GLState::BufferBindingPointCount));
             break;
         case GL_MAX_UNIFORM_BLOCK_SIZE:
             *params = dynamicParameters.MaxUniformBlockSize;
@@ -1955,6 +1975,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_MAX_SAMPLES:
             *params = std::max(dynamicParameters.MaxSamples, kFrontendMaxSamples);
             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);
             MG_State::pGLContext->RecordError(ErrorCode::InvalidEnum,
@@ -1972,4 +1996,12 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
         return MG_Util::ConvertErrorCodeToGLEnum(error->get()->code);
     }
+
+    GLenum GetGraphicsResetStatus() {
+        // MobileGL does not implement robustness reset notification, so report GL_NO_ERROR
+        // ("no reset detected"). Returning the generic stub's (GLenum)1 makes dEQP read a lost
+        // device after every case (gl3cTestPackages.cpp:121) and, under the default
+        // --deqp-terminate-on-device-lost=enable, tear the whole CTS run down.
+        return GL_NO_ERROR;
+    }
 } // namespace MobileGL::MG_Impl::GLImpl

MobileGL/MG_Impl/GLImpl/Getter/GL_Getter.h

@@ -21,4 +21,5 @@ namespace MobileGL::MG_Impl::GLImpl {
     void GetIntegeri_v(GLenum target, GLuint index, GLint* data);
     void GetInteger64i_v(GLenum target, GLuint index, GLint64* data);
     GLenum GetError();
+    GLenum GetGraphicsResetStatus();
 } // namespace MobileGL::MG_Impl::GLImpl

MobileGL/MG_Impl/GLImpl/Program/GL_Program.cpp

@@ -339,6 +339,9 @@ namespace MobileGL::MG_Impl::GLImpl {
                 MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__, "Shader is not attached to program."));
             return;
         }
+        // A shader flagged with glDeleteShader lives on while attached; this detach may
+        // have been its last GL-visible attachment.
+        MG_State::pGLContext->ReleaseShaderNameIfOrphaned(shader);
     }
 
     void GetActiveAttrib_State(GLuint program, GLuint index, GLsizei bufSize, GLsizei* length, GLint* size,
@@ -735,6 +738,12 @@ namespace MobileGL::MG_Impl::GLImpl {
             auto size = programObject->GetUniformSizesInBytes(location);
             char* pUBO = (char*)programObject->MapUBO();
             auto* ttype = programObject->GetUniformTType(location);
+            if (pUBO == nullptr || offset == MG_State::GLState::ProgramObject::kInvalidUniformOffset ||
+                offset + size > programObject->GetUBOSize()) {
+                MGLOG_E("%s: uniform at program %u location %d has no backing storage; returning nothing", __func__,
+                        program, location);
+                return;
+            }
 
             if (!ttype->isMatrix() || ttype->getMatrixCols() != 3)
                 Memcpy(params, pUBO + offset, size);
@@ -784,6 +793,12 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto size = programObject->GetUniformSizesInBytes(location);
         char* pUBO = static_cast<char*>(programObject->MapUBO());
         auto* ttype = programObject->GetUniformTType(location);
+        if (pUBO == nullptr || offset == MG_State::GLState::ProgramObject::kInvalidUniformOffset ||
+            offset + size > programObject->GetUBOSize()) {
+            MGLOG_E("%s: uniform at program %u location %d has no backing storage; returning nothing", __func__,
+                    program, location);
+            return;
+        }
 
         if constexpr (std::is_same_v<T, GLfloat>) {
             if (ttype->isMatrix() && ttype->getMatrixCols() == 3) {
@@ -900,14 +915,31 @@ namespace MobileGL::MG_Impl::GLImpl {
         if (!programObject.IsUniformOpaqueAtLocation(location)) {
             MGLOG_D("%s: program = %d, location = %d, maxLocation = %d", __func__, programObject.GetExternalIndex(),
                     location, programObject.GetMaxUniformLocation());
-            auto size = programObject.GetUniformSizesInBytes(location);
-            auto offset = programObject.GetUniformOffset(location);
-            MOBILEGL_ASSERT(size >= ItemCount * sizeof(T),
-                            "Uniform size mismatch, expected at least %zu bytes, got %zu bytes.", ItemCount * sizeof(T),
-                            size);
+            const SizeT size = programObject.GetUniformSizesInBytes(location);
+            const Uint offset = programObject.GetUniformOffset(location);
+            char* pUBO = static_cast<char*>(programObject.MapUBO());
+            const SizeT uboSize = programObject.GetUBOSize();
+            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 "
+                        "bytes; clamping",
+                        __func__, programObject.GetExternalIndex(), location, ItemCount * sizeof(T), size);
+                writeSize = size;
+            }
+            if (pUBO == nullptr || offset == MG_State::GLState::ProgramObject::kInvalidUniformOffset ||
+                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 "
+                        "uboSize=%zu); dropping write",
+                        __func__, programObject.GetExternalIndex(), location, static_cast<void*>(pUBO), offset,
+                        writeSize, uboSize);
+                return;
+            }
             MGLOG_D("%s: program = %d, location = %d, byteOffset = %d", __func__, programObject.GetExternalIndex(),
                     location, offset + byteOffsetInsideUniform);
-            Memcpy((char*)programObject.MapUBO() + offset + byteOffsetInsideUniform, value, ItemCount * sizeof(T));
+            Memcpy(pUBO + offset + byteOffsetInsideUniform, value, writeSize);
             programObject.MarkUBOContentDirty();
         } else {
             auto* ttype = programObject.GetUniformTType(location);
@@ -940,6 +972,11 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
 
         for (GLint offset = 0; offset < count; offset++) {
+            if (offset > 0 && !programObject->UniformLocationsAliasSameUniform(location, location + offset)) {
+                // GL 3.3 §2.11.4: values for elements beyond the end of the uniform
+                // array are ignored. Never step onto a neighboring uniform's location.
+                break;
+            }
             if (!programObject->IsValidUniformLocation(location + offset)) {
                 RecordInvalidUniformLocationError(__func__, location + offset, "the current program object");
                 return;
@@ -964,6 +1001,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
 
         for (GLint offset = 0; offset < count; offset++) {
+            if (offset > 0 && !programObject->UniformLocationsAliasSameUniform(location, location + offset)) {
+                // Values for elements beyond the end of the uniform array are ignored.
+                break;
+            }
             if (!programObject->IsValidUniformLocation(location + offset)) {
                 RecordInvalidUniformLocationError(__func__, location + offset,
                                                   "program " + std::to_string(program));
@@ -1092,6 +1133,10 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         // For matrix uniforms, we handle each matrix individually
         for (GLint i = 0; i < count; i++) {
+            if (i > 0 && !programObject->UniformLocationsAliasSameUniform(location, location + i)) {
+                // Values for elements beyond the end of the uniform array are ignored.
+                break;
+            }
             if (!programObject->IsValidUniformLocation(location + i)) {
                 RecordInvalidUniformLocationError(__func__, location + i, "the current program object");
                 return;
@@ -1124,6 +1169,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         // For matrix uniforms, we handle each matrix individually
         // Handle padding in mat3 correctly!!
         for (GLint i = 0; i < count; i++) {
+            if (i > 0 && !programObject->UniformLocationsAliasSameUniform(location, location + i)) {
+                // Values for elements beyond the end of the uniform array are ignored.
+                break;
+            }
             if (!programObject->IsValidUniformLocation(location + i)) {
                 RecordInvalidUniformLocationError(__func__, location + i, "the current program object");
                 return;
@@ -1159,6 +1208,10 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         // For matrix uniforms, we handle each matrix individually
         for (GLint i = 0; i < count; i++) {
+            if (i > 0 && !programObject->UniformLocationsAliasSameUniform(location, location + i)) {
+                // Values for elements beyond the end of the uniform array are ignored.
+                break;
+            }
             if (!programObject->IsValidUniformLocation(location + i)) {
                 RecordInvalidUniformLocationError(__func__, location + i, "the current program object");
                 return;
@@ -1219,6 +1272,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
 
         for (GLint i = 0; i < count; i++) {
+            if (i > 0 && !programObject->UniformLocationsAliasSameUniform(location, location + i)) {
+                // Values for elements beyond the end of the uniform array are ignored.
+                break;
+            }
             if (!programObject->IsValidUniformLocation(location + i)) {
                 RecordInvalidUniformLocationError(__func__, location + i, "program " + std::to_string(program));
                 return;
@@ -1249,6 +1306,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
 
         for (GLint i = 0; i < count; i++) {
+            if (i > 0 && !programObject->UniformLocationsAliasSameUniform(location, location + i)) {
+                // Values for elements beyond the end of the uniform array are ignored.
+                break;
+            }
             if (!programObject->IsValidUniformLocation(location + i)) {
                 RecordInvalidUniformLocationError(__func__, location + i, "program " + std::to_string(program));
                 return;
@@ -1283,6 +1344,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
 
         for (GLint i = 0; i < count; i++) {
+            if (i > 0 && !programObject->UniformLocationsAliasSameUniform(location, location + i)) {
+                // Values for elements beyond the end of the uniform array are ignored.
+                break;
+            }
             if (!programObject->IsValidUniformLocation(location + i)) {
                 RecordInvalidUniformLocationError(__func__, location + i, "program " + std::to_string(program));
                 return;
@@ -1341,6 +1406,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
 
         const auto& index = programObject->GetUniformBlockIndex(uniformBlockName);
+        MGLOG_D("GBI prog=%u name='%s' -> %d", program, uniformBlockName ? uniformBlockName : "(null)", (Int)index);
         return index;
     }
 
@@ -1364,6 +1430,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                         std::to_string(program) + "."));
             return;
         }
+        MGLOG_D("UBB prog=%u idx=%u binding=%u", program, uniformBlockIndex, uniformBlockBinding);
         programObject->SetUniformBlockBinding(uniformBlockIndex, uniformBlockBinding);
     }
 
@@ -1435,9 +1502,13 @@ namespace MobileGL::MG_Impl::GLImpl {
             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));
             GLint uniformIndexCount = 0;
             for (Uint uniformIndex = 0; uniformIndex < programObject->GetUniformCount(); ++uniformIndex) {
-                if (programObject->GetActiveUniformBlockIndex(uniformIndex) != static_cast<Int>(uniformBlockIndex)) {
+                if (programObject->GetActiveUniformBlockIndex(uniformIndex) != ownerIndex) {
                     continue;
                 }
                 params[uniformIndexCount++] = static_cast<GLint>(uniformIndex);

MobileGL/MG_Impl/GLImpl/RenderState/GL_RenderState.cpp

@@ -649,7 +649,9 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void ClearDepth_State(GLclampd depth) {
-        MG_State::pGLContext->SetClearDepth(static_cast<Float>(depth));
+        // GL 3.3 §4.2.3: the clear depth is clamped to [0,1] at specification time (Vulkan clear
+        // values additionally require it: VUID-VkClearDepthStencilValue-depth-00022).
+        MG_State::pGLContext->SetClearDepth(ClampUnitFloat(static_cast<Float>(depth)));
     }
 
     void ClearColor_State(GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha) {

MobileGL/MG_Impl/GLImpl/Sampler/GL_Sampler.cpp

@@ -233,7 +233,16 @@ namespace MobileGL::MG_Impl::GLImpl {
         if (sampler == 0) {
             textureUnit.SetSamplerObject(nullptr);
         } else {
-            if (!SamplerImpl::ValidateSamplerName(sampler)) return;
+            // GL 3.3 core 3.8.2: BindSampler on a name GenSamplers never returned - or one already
+            // deleted - is INVALID_OPERATION. SamplerParameter* raises INVALID_VALUE for the same
+            // name, which is why this cannot go through the shared SamplerImpl validator.
+            if (!MG_State::pGLContext->ValidateSamplerName(sampler)) {
+                MG_State::pGLContext->RecordError(
+                    ErrorCode::InvalidOperation,
+                    MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "BindSampler_State",
+                                                 std::format("Invalid sampler name {}", sampler)));
+                return;
+            }
             Bool doesSamplerObjectCreated = MG_State::pGLContext->ValidateSamplerObject(sampler);
             if (!doesSamplerObjectCreated) {
                 MG_State::pGLContext->CreateSamplerObject(sampler);

MobileGL/MG_Impl/GLImpl/Texture/GL_Texture.cpp

@@ -294,10 +294,16 @@ namespace MobileGL::MG_Impl::GLImpl {
                 MG_State::GLState::TextureState::MAX_TEXTURE_IMAGE_UNITS));
         }
 
-        Uint ComputeFullMipmapLevelCount(const IntVec3& baseTexelSize) {
+        // Array targets store their layer count in z; layers never participate in mip
+        // reduction (GL 3.3 §3.8.14), only true 3D textures halve their depth per level.
+        Bool DepthParticipatesInMipmapping(TextureTarget target) {
+            return target == TextureTarget::Texture3D;
+        }
+
+        Uint ComputeFullMipmapLevelCount(const IntVec3& baseTexelSize, Bool depthMips) {
             Int maxDimension = std::max<Int>(
                 baseTexelSize.x(),
-                std::max<Int>(baseTexelSize.y(), std::max<Int>(baseTexelSize.z(), 1)));
+                std::max<Int>(baseTexelSize.y(), depthMips ? std::max<Int>(baseTexelSize.z(), 1) : 1));
             Uint mipLevelCount = 1;
             while (maxDimension > 1) {
                 maxDimension = std::max<Int>(maxDimension / 2, 1);
@@ -306,11 +312,12 @@ namespace MobileGL::MG_Impl::GLImpl {
             return mipLevelCount;
         }
 
-        IntVec3 ComputeMipmapTexelSize(const IntVec3& baseTexelSize, Uint relativeLevel) {
+        IntVec3 ComputeMipmapTexelSize(const IntVec3& baseTexelSize, Uint relativeLevel, Bool depthMips) {
             return {
                 std::max<Int>(baseTexelSize.x() >> static_cast<Int>(relativeLevel), 1),
                 std::max<Int>(baseTexelSize.y() >> static_cast<Int>(relativeLevel), 1),
-                std::max<Int>(baseTexelSize.z() >> static_cast<Int>(relativeLevel), 1),
+                depthMips ? std::max<Int>(baseTexelSize.z() >> static_cast<Int>(relativeLevel), 1)
+                          : std::max<Int>(baseTexelSize.z(), 1),
             };
         }
 
@@ -333,15 +340,20 @@ namespace MobileGL::MG_Impl::GLImpl {
             }
 
             const SizeT bytesPerTexel = baseByteSize / baseTexelCount;
-            const Uint requiredLevelCount = ComputeFullMipmapLevelCount(baseTexelSize);
+            const Bool depthMips = DepthParticipatesInMipmapping(texture.GetTarget());
+            const Uint requiredLevelCount = ComputeFullMipmapLevelCount(baseTexelSize, depthMips);
             for (Uint level = 1; level < requiredLevelCount; ++level) {
-                const IntVec3 levelTexelSize = ComputeMipmapTexelSize(baseTexelSize, level);
+                const IntVec3 levelTexelSize = ComputeMipmapTexelSize(baseTexelSize, level, depthMips);
                 const SizeT levelByteSize = bytesPerTexel * static_cast<SizeT>(levelTexelSize.x()) *
                                             static_cast<SizeT>(levelTexelSize.y()) *
                                             static_cast<SizeT>(levelTexelSize.z());
                 texture.AllocateStorage(uploadTarget, level, {levelTexelSize, levelByteSize});
                 texture.MarkStorageDirty(uploadTarget, level, false);
             }
+            // glGenerateMipmap defines exactly levels 0..requiredLevelCount-1. AllocateStorage only
+            // grows, so a previously longer chain (a bigger base image before respecification) would
+            // otherwise keep a tail of stale levels here and read as incomplete.
+            texture.TruncateMipmapLevels(uploadTarget, requiredLevelCount);
             // Mip generation grows/regenerates the level set on the GPU without marking any CPU
             // level dirty (MarkStorageDirty(...,false) above). Bump the content version so the
             // backend re-syncs: a cached sampled VkImageView built for the pre-generate level
@@ -414,18 +426,17 @@ namespace MobileGL::MG_Impl::GLImpl {
                                                  "2D multisample textures must use depth 1."));
                 return false;
             }
-            if (textureTarget == TextureTarget::Texture2DMultisampleArray && depth == 0) {
-                MG_State::pGLContext->RecordError(
-                    ErrorCode::InvalidValue,
-                    MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", caller,
-                                                 "2D multisample array textures must have at least one layer."));
-                return false;
-            }
+            // Zero layers is NOT an error for multisample arrays: depth == 0 (like width/height
+            // == 0) deallocates the image - GL 4.5 8.8 only raises INVALID_VALUE for negative
+            // dimensions, and GL CTS's per-case state reset (gluStateReset) clears the default
+            // GL_TEXTURE_2D_MULTISAMPLE_ARRAY texture with glTexImage3DMultisample(..., 0, 0, 0).
 
             const Int maxSamples = GetMaxSupportedTextureSamples(textureInternalFormat);
             if (samples > maxSamples) {
+                // GL specifies INVALID_OPERATION - not INVALID_VALUE - when the sample count
+                // exceeds what the format supports, and the native Adreno driver agrees.
                 MG_State::pGLContext->RecordError(
-                    ErrorCode::InvalidValue,
+                    ErrorCode::InvalidOperation,
                     MakeUnique<GenericErrorInfo>(
                         "MG_Impl/GLImpl", caller,
                         std::format("Sample count {} exceeds the supported maximum {} for this texture format.",
@@ -449,8 +460,56 @@ namespace MobileGL::MG_Impl::GLImpl {
             textureObject->SetSamples(samples);
             textureObject->SetFixedSampleLocations(fixedsamplelocations == GL_TRUE);
             textureMipmapObject->AllocateStorage(textureUploadTarget, 0, {{width, height, depth}, 0});
+            // Multisample textures are single-level by definition, so a name that previously held a
+            // mip chain must not keep its tail now that AllocateStorage only grows.
+            textureMipmapObject->TruncateMipmapLevels(textureUploadTarget, 1);
             textureMipmapObject->MarkStorageDirty(textureUploadTarget, 0, false);
         }
+
+        // Redefining level 0 of a texture that already had a base image drops the rest of the chain,
+        // which is exactly what AllocateLevel used to do implicitly for every level. Keeping that
+        // behaviour for level 0 - and only for level 0 - is what makes the grow-only change safe:
+        // any level-0 respecification leaves the chain in precisely the state it would have had
+        // before, while an upload to level N no longer destroys the levels beneath it.
+        //
+        // Why it has to be *every* level-0 respecification and not just a size change: Minecraft's
+        // Mipmap Levels setting rebuilds the block atlas at the SAME dimensions with a different
+        // level count. A size-only test would leave the old tail in place, and because Mojang
+        // terminates its chains with a 0x0 level the result is the zero-then-nonzero pattern that
+        // IsComplete() rejects (TextureObject.cpp) - whereupon DirectGLES skips syncing the texture
+        // entirely (Managers.cpp) and the atlas samples black.
+        //
+        // The "already has a base image" test is what lets the fix work at all: a level that was
+        // never written reads back as {0,0,0}, so building a chain top-down - upload level N first,
+        // then level 0 - must not discard the levels just uploaded. That ordering is what
+        // KHR-GL33.texture_repeat_mode does.
+        // Scoped to the respecified upload target only, which is what AllocateLevel already did.
+        // Cube maps keep six independent chains while reporting a single level count (face +X), so
+        // respecifying a face other than +X can leave the count longer than that face - but that
+        // asymmetry predates this change and widening the truncation to all six faces would destroy
+        // mip data for faces the application never touched. Left alone deliberately.
+        void DiscardMipmapChainOnBaseRespecification(MG_State::GLState::TextureObjectMipmap* texture,
+                                                     TextureUploadTarget uploadTarget, Uint level) {
+            if (level != 0) return;
+
+            const IntVec3 existingBaseSize = texture->GetMipmapTexelSize(uploadTarget, 0);
+            const Bool hasExistingBaseImage =
+                existingBaseSize.x() > 0 && existingBaseSize.y() > 0 && existingBaseSize.z() > 0;
+            if (!hasExistingBaseImage) return;
+
+            texture->TruncateMipmapLevels(uploadTarget, 1);
+        }
+
+        // Compressed texture upload is not implemented yet. GL_NUM_COMPRESSED_TEXTURE_FORMATS
+        // reports 0, so every compressed internalformat is by definition unsupported and
+        // GL_INVALID_ENUM is the specified error - unlike THROW_UNIMPL_EXCEPTION, which unwinds
+        // a C++ exception through the C GL ABI and takes the process down.
+        void RecordUnsupportedCompressedFormat(const char* caller) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidEnum,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", caller,
+                                             "Compressed texture formats are not supported."));
+        }
     } // namespace
 
     const SharedPtr<MG_State::GLState::ITextureObject>& GetTextureObjectByName(GLuint texture, const char* caller) {
@@ -465,6 +524,223 @@ namespace MobileGL::MG_Impl::GLImpl {
         return textureObject;
     }
 
+    namespace {
+        void RecordClearTextureError(const char* caller, ErrorCode code, const String& message) {
+            MG_State::pGLContext->RecordError(
+                code, MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", caller, message));
+        }
+
+        SharedPtr<MG_State::GLState::TextureObjectMipmap> GetClearTextureObject(GLuint texture, GLint level,
+                                                                                const char* caller) {
+            if (texture == 0) {
+                RecordClearTextureError(caller, ErrorCode::InvalidOperation,
+                                        "Clear texture operations require a non-zero texture name.");
+                return nullptr;
+            }
+
+            auto textureObject = GetTextureObjectByName(texture, caller);
+            if (!textureObject) return nullptr;
+            if (textureObject->GetStorageType() != TextureStorageType::Mipmap) {
+                RecordClearTextureError(caller, ErrorCode::InvalidOperation,
+                                        "Buffer textures cannot be cleared with glClearTexImage.");
+                return nullptr;
+            }
+
+            auto mipmapTexture = std::static_pointer_cast<MG_State::GLState::TextureObjectMipmap>(textureObject);
+            if (level < 0) {
+                RecordClearTextureError(caller, ErrorCode::InvalidValue,
+                                        std::format("Texture level {} is negative.", level));
+                return nullptr;
+            }
+            // ARB_clear_texture: clearing an image that was never defined by TexImage*/
+            // TexStorage* is INVALID_OPERATION, not INVALID_VALUE.
+            if (static_cast<Uint>(level) >= mipmapTexture->GetMipmapLevelCount()) {
+                RecordClearTextureError(caller, ErrorCode::InvalidOperation,
+                                        std::format("Texture level {} is not defined.", level));
+                return nullptr;
+            }
+            return mipmapTexture;
+        }
+
+        Bool BuildClearPixel(const SharedPtr<MG_State::GLState::TextureObjectMipmap>& textureObject,
+                             GLenum format, GLenum type, const void* data, Vector<Uint8>& clearPixel) {
+            const TextureInputFormat inputFormat = MG_Util::ConvertGLEnumToTextureInputFormat(format);
+            const TexturePixelDataType inputType = MG_Util::ConvertGLEnumToTexturePixelDataType(type);
+            if (!TextureImpl::ValidateTextureInputFormat(inputFormat) ||
+                !TextureImpl::ValidateTexturePixelDataType(inputType) ||
+                !TextureImpl::ValidateTextureInternalFormatCompatibleWithInput(
+                    inputFormat, textureObject->GetFormat(), inputType)) {
+                return false;
+            }
+
+            clearPixel.clear();
+            if (data == nullptr) {
+                // ARB_clear_texture defines a null clear value as all zeroes. Keeping the
+                // pattern empty lets the region writer use a fast memset path.
+                return true;
+            }
+
+            PixelStoreParameters clearPixelStore{};
+            clearPixelStore.Alignment = 1;
+            SizeT clearPixelSize = 0;
+            void* converted = MG_Util::PixelStoreProcessor::ProcessTexturePixelsDataUnpack(
+                data, clearPixelStore, textureObject->GetFormat(), inputFormat, inputType,
+                {1, 1, 1}, false, clearPixelSize);
+            if (!converted || clearPixelSize == 0) {
+                if (converted) free(converted);
+                return false;
+            }
+
+            clearPixel.resize(clearPixelSize);
+            Memcpy(clearPixel.data(), converted, clearPixelSize);
+            free(converted);
+            return true;
+        }
+
+        // Writes the clear into the CPU shadow and marks the whole level dirty, exactly like
+        // TexSubImage*_State does. Shared limitation of the level-granular shadow sync: the
+        // shadow does not reflect GPU-side writes (FBO rendering, imageStore), so a PARTIAL
+        // clear of a GPU-written level re-uploads stale shadow bytes outside the region on
+        // the next sync. Full-level clears (glClearTexImage, or a sub-clear covering the
+        // level) rewrite the entire shadow and are always correct.
+        Bool ClearMipmapRegion(const SharedPtr<MG_State::GLState::TextureObjectMipmap>& textureObject,
+                               TextureUploadTarget uploadTarget, GLint level,
+                               GLint xoffset, GLint yoffset, GLint zoffset,
+                               GLsizei width, GLsizei height, GLsizei depth,
+                               const Vector<Uint8>& clearPixel, const char* caller) {
+            const IntVec3 texelSize = textureObject->GetMipmapTexelSize(uploadTarget, static_cast<Uint>(level));
+            if (texelSize.x() <= 0 || texelSize.y() <= 0 || texelSize.z() <= 0) {
+                RecordClearTextureError(caller, ErrorCode::InvalidOperation,
+                                        "The requested texture level has no storage.");
+                return false;
+            }
+            if (xoffset < 0 || yoffset < 0 || zoffset < 0 ||
+                width < 0 || height < 0 || depth < 0 ||
+                width > texelSize.x() - xoffset ||
+                height > texelSize.y() - yoffset ||
+                depth > texelSize.z() - zoffset) {
+                RecordClearTextureError(caller, ErrorCode::InvalidValue,
+                                        "The clear region lies outside the requested texture level.");
+                return false;
+            }
+            if (width == 0 || height == 0 || depth == 0) return true;
+
+            const SizeT texelCount = static_cast<SizeT>(texelSize.x()) *
+                                     static_cast<SizeT>(texelSize.y()) *
+                                     static_cast<SizeT>(texelSize.z());
+            const SizeT byteSize = textureObject->GetMipmapByteSize(uploadTarget, static_cast<Uint>(level));
+            if (byteSize == 0 || byteSize % texelCount != 0) {
+                RecordClearTextureError(caller, ErrorCode::InvalidOperation,
+                                        "The requested texture storage cannot be cleared.");
+                return false;
+            }
+
+            const SizeT bytesPerTexel = byteSize / texelCount;
+            if (!clearPixel.empty() && clearPixel.size() != bytesPerTexel) {
+                RecordClearTextureError(
+                    caller, ErrorCode::InvalidOperation,
+                    std::format("Converted clear value is {} bytes, but the texture stores {} bytes per texel.",
+                                clearPixel.size(), bytesPerTexel));
+                return false;
+            }
+
+            auto* destination = static_cast<Uint8*>(
+                textureObject->MapMipmapData(uploadTarget, static_cast<Uint>(level)));
+            if (!destination) {
+                RecordClearTextureError(caller, ErrorCode::InvalidOperation,
+                                        "The requested texture level could not be mapped.");
+                return false;
+            }
+
+            const SizeT fullRowBytes = static_cast<SizeT>(texelSize.x()) * bytesPerTexel;
+            const SizeT fullSliceBytes = static_cast<SizeT>(texelSize.y()) * fullRowBytes;
+            const SizeT clearRowBytes = static_cast<SizeT>(width) * bytesPerTexel;
+            Uint8* firstClearRow = nullptr;
+
+            for (GLsizei z = 0; z < depth; ++z) {
+                for (GLsizei y = 0; y < height; ++y) {
+                    Uint8* row = destination +
+                                 static_cast<SizeT>(zoffset + z) * fullSliceBytes +
+                                 static_cast<SizeT>(yoffset + y) * fullRowBytes +
+                                 static_cast<SizeT>(xoffset) * bytesPerTexel;
+                    if (firstClearRow) {
+                        Memcpy(row, firstClearRow, clearRowBytes);
+                        continue;
+                    }
+
+                    firstClearRow = row;
+                    if (clearPixel.empty()) {
+                        Memset(row, 0, clearRowBytes);
+                        continue;
+                    }
+
+                    Memcpy(row, clearPixel.data(), bytesPerTexel);
+                    SizeT filled = bytesPerTexel;
+                    while (filled < clearRowBytes) {
+                        const SizeT copySize = std::min(filled, clearRowBytes - filled);
+                        Memcpy(row + filled, row, copySize);
+                        filled += copySize;
+                    }
+                }
+            }
+
+            textureObject->MarkStorageDirty(uploadTarget, static_cast<Uint>(level), true);
+            return true;
+        }
+    } // namespace
+
+    void ClearTexImage(GLuint texture, GLint level, GLenum format, GLenum type, const void* data) {
+        auto textureObject = GetClearTextureObject(texture, level, __func__);
+        if (!textureObject) return;
+
+        Vector<Uint8> clearPixel;
+        if (!BuildClearPixel(textureObject, format, type, data, clearPixel)) return;
+
+        for (TextureUploadTarget uploadTarget : textureObject->GetUploadTargets()) {
+            const IntVec3 size = textureObject->GetMipmapTexelSize(uploadTarget, static_cast<Uint>(level));
+            if (!ClearMipmapRegion(textureObject, uploadTarget, level, 0, 0, 0,
+                                   size.x(), size.y(), size.z(), clearPixel, __func__)) {
+                return;
+            }
+        }
+    }
+
+    void ClearTexSubImage(GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint zoffset,
+                          GLsizei width, GLsizei height, GLsizei depth, GLenum format, GLenum type,
+                          const void* data) {
+        auto textureObject = GetClearTextureObject(texture, level, __func__);
+        if (!textureObject) return;
+
+        Vector<Uint8> clearPixel;
+        if (!BuildClearPixel(textureObject, format, type, data, clearPixel)) return;
+
+        const auto& uploadTargets = textureObject->GetUploadTargets();
+        if (textureObject->GetTarget() == TextureTarget::TextureCubeMap) {
+            if (zoffset < 0 || depth < 0 ||
+                static_cast<SizeT>(zoffset) > uploadTargets.size() ||
+                static_cast<SizeT>(depth) > uploadTargets.size() - static_cast<SizeT>(zoffset)) {
+                RecordClearTextureError(__func__, ErrorCode::InvalidValue,
+                                        "The cube-map clear region selects invalid faces.");
+                return;
+            }
+            for (GLsizei face = 0; face < depth; ++face) {
+                if (!ClearMipmapRegion(textureObject, uploadTargets[static_cast<SizeT>(zoffset + face)], level,
+                                       xoffset, yoffset, 0, width, height, 1, clearPixel, __func__)) {
+                    return;
+                }
+            }
+            return;
+        }
+
+        if (uploadTargets.empty()) {
+            RecordClearTextureError(__func__, ErrorCode::InvalidOperation,
+                                    "The requested texture has no upload target.");
+            return;
+        }
+        ClearMipmapRegion(textureObject, uploadTargets.front(), level, xoffset, yoffset, zoffset,
+                          width, height, depth, clearPixel, __func__);
+    }
+
     Bool ValidateTextureParameterForTarget(const SharedPtr<MG_State::GLState::ITextureObject>& textureObject,
                                            GLenum pname, GLint param, const char* caller) {
         const auto target = textureObject->GetTarget();
@@ -571,6 +847,14 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_TEXTURE_SWIZZLE_A: {
             auto swizzleParam = MG_Util::ConvertGLEnumPnameToTextureSwizzleParam(pname);
             auto swizzleValue = MG_Util::ConvertGLEnumToTextureSwizzleParam(param);
+            if (swizzleValue == TextureSwizzleParam::Unknown) {
+                // GL CTS texture_swizzle.api_errors: single-value TexParameter* with a value outside
+                // [RED, GREEN, BLUE, ALPHA, ZERO, ONE] must raise GL_INVALID_ENUM.
+                MG_State::pGLContext->RecordError(
+                    ErrorCode::InvalidEnum,
+                    MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", caller, "Invalid texture swizzle value."));
+                return;
+            }
             textureObject->SetSwizzleParam(swizzleParam, swizzleValue);
             break;
         }
@@ -760,6 +1044,23 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
     }
 
+    // Texture-parameter lookups must not raise GL_INVALID_OPERATION when the default texture
+    // (name 0) is bound: glTexParameter* on default textures is legal GL (the GL CTS state reset
+    // sets swizzles/levels on texture 0 for every unit x target and expects glGetError() to stay
+    // clean). Name 0 resolves to the target's real default texture object, so parameters set on
+    // it are stored and queryable like on any texture.
+    const SharedPtr<MG_State::GLState::ITextureObject>& GetTextureObjectByTargetForParameter(
+        TextureUploadTarget textureUploadTarget, TextureTarget textureTarget) {
+        if (TextureImpl::IsProxyTextureTarget(textureUploadTarget)) {
+            return TextureImpl::pProxyTextureManager->GetProxyTextureObject(textureUploadTarget);
+        }
+        if (textureTarget == TextureTarget::Unknown) {
+            return nullTextureObject;
+        }
+        auto& activeUnit = MG_State::pGLContext->GetTextureUnitObject(MG_State::pGLContext->GetActiveTextureUnit());
+        return activeUnit.GetBindingSlot(textureTarget).GetBoundObject();
+    }
+
     void GenerateMipmap_Backend(GLenum target) {
         MG_Backend::gBackendFunctionsTable.GL.GenerateMipmap(target);
     }
@@ -805,6 +1106,12 @@ namespace MobileGL::MG_Impl::GLImpl {
         MOBILEGL_ASSERT(nullptr != static_cast<MG_State::GLState::TextureObjectMipmap*>(textureObject.get()),
                         "Texture object here should always be an object with mipmap");
         auto textureMipmapObject = static_cast<MG_State::GLState::TextureObjectMipmap*>(textureObject.get());
+        if (static_cast<Uint>(level) >= textureMipmapObject->GetMipmapLevelCount()) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidValue,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__, "Texture level is out of range."));
+            return;
+        }
 
         const void* originalPixels = pixels;
         const auto& pixelUnpackBufferObject =
@@ -837,6 +1144,14 @@ namespace MobileGL::MG_Impl::GLImpl {
         const SizeT destRowSize = static_cast<SizeT>(texelSize.x()) * internalBpp;
         const SizeT destSliceSize = static_cast<SizeT>(texelSize.y()) * destRowSize;
 
+        if (xoffset + width > static_cast<GLsizei>(texelSize.x()) ||
+            yoffset + height > static_cast<GLsizei>(texelSize.y()) ||
+            zoffset + depth > static_cast<GLsizei>(texelSize.z())) {
+            MGLOG_E("TexSubImage3D_State: Specified region exceeds texture level dimensions");
+            free(processedPixels);
+            return;
+        }
+
         const auto* srcData = static_cast<const Uint8*>(processedPixels);
         Uint8* destData = static_cast<Uint8*>(textureMipmapObject->MapMipmapData(textureUploadTarget, level));
         if (destData) {
@@ -1053,7 +1368,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         TextureTarget textureTarget = MG_Util::ConvertGLEnumToTextureTarget(target);
 
         // ======================= Processing ================================
-        auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
+        auto& textureObject = GetTextureObjectByTargetForParameter(textureUploadTarget, textureTarget);
         if (!textureObject) return;
 
         switch (pname) {
@@ -1086,6 +1401,12 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_TEXTURE_SWIZZLE_A: {
             auto swizzleParam = MG_Util::ConvertGLEnumPnameToTextureSwizzleParam(pname);
             auto swizzleValue = MG_Util::ConvertGLEnumToTextureSwizzleParam((GLenum)param);
+            if (swizzleValue == TextureSwizzleParam::Unknown) {
+                MG_State::pGLContext->RecordError(
+                    ErrorCode::InvalidEnum,
+                    MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__, "Invalid texture swizzle value."));
+                return;
+            }
             textureObject->SetSwizzleParam(swizzleParam, swizzleValue);
             break;
         }
@@ -1136,7 +1457,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         TextureTarget textureTarget = MG_Util::ConvertGLEnumToTextureTarget(target);
 
         // ======================= Processing ================================
-        auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
+        auto& textureObject = GetTextureObjectByTargetForParameter(textureUploadTarget, textureTarget);
         if (!textureObject) return;
 
         TextureParameterObject_State(textureObject, pname, param, __func__);
@@ -1152,7 +1473,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             TextureTarget textureTarget = MG_Util::ConvertGLEnumToTextureTarget(target);
 
             // ======================= Processing ================================
-            auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
+            auto& textureObject = GetTextureObjectByTargetForParameter(textureUploadTarget, textureTarget);
             if (!textureObject) return;
             SetTextureBorderColorFromFloats(textureObject, params);
             break;
@@ -1160,7 +1481,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_TEXTURE_SWIZZLE_RGBA: {
             TextureUploadTarget textureUploadTarget = MG_Util::ConvertGLEnumToTextureUploadTarget(target);
             TextureTarget textureTarget = MG_Util::ConvertGLEnumToTextureTarget(target);
-            auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
+            auto& textureObject = GetTextureObjectByTargetForParameter(textureUploadTarget, textureTarget);
             if (!textureObject) return;
             GLint signedParams[4] = {static_cast<GLint>(params[0]), static_cast<GLint>(params[1]),
                                      static_cast<GLint>(params[2]), static_cast<GLint>(params[3])};
@@ -1183,7 +1504,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             TextureTarget textureTarget = MG_Util::ConvertGLEnumToTextureTarget(target);
 
             // ======================= Processing ================================
-            auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
+            auto& textureObject = GetTextureObjectByTargetForParameter(textureUploadTarget, textureTarget);
             if (!textureObject) return;
             SetTextureBorderColorFromInts(textureObject, params);
             break;
@@ -1191,7 +1512,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_TEXTURE_SWIZZLE_RGBA: {
             TextureUploadTarget textureUploadTarget = MG_Util::ConvertGLEnumToTextureUploadTarget(target);
             TextureTarget textureTarget = MG_Util::ConvertGLEnumToTextureTarget(target);
-            auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
+            auto& textureObject = GetTextureObjectByTargetForParameter(textureUploadTarget, textureTarget);
             if (!textureObject) return;
             if (!SetTextureSwizzleParamsFromInts(textureObject, params, __func__)) {
                 return;
@@ -1209,7 +1530,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_TEXTURE_BORDER_COLOR: {
             TextureUploadTarget textureUploadTarget = MG_Util::ConvertGLEnumToTextureUploadTarget(target);
             TextureTarget textureTarget = MG_Util::ConvertGLEnumToTextureTarget(target);
-            auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
+            auto& textureObject = GetTextureObjectByTargetForParameter(textureUploadTarget, textureTarget);
             if (!textureObject) return;
             SetTextureBorderColorFromIntegerInts(textureObject, params);
             break;
@@ -1217,7 +1538,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_TEXTURE_SWIZZLE_RGBA: {
             TextureUploadTarget textureUploadTarget = MG_Util::ConvertGLEnumToTextureUploadTarget(target);
             TextureTarget textureTarget = MG_Util::ConvertGLEnumToTextureTarget(target);
-            auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
+            auto& textureObject = GetTextureObjectByTargetForParameter(textureUploadTarget, textureTarget);
             if (!textureObject) return;
             GLint signedParams[4] = {static_cast<GLint>(params[0]), static_cast<GLint>(params[1]),
                                      static_cast<GLint>(params[2]), static_cast<GLint>(params[3])};
@@ -1237,7 +1558,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         case GL_TEXTURE_BORDER_COLOR: {
             TextureUploadTarget textureUploadTarget = MG_Util::ConvertGLEnumToTextureUploadTarget(target);
             TextureTarget textureTarget = MG_Util::ConvertGLEnumToTextureTarget(target);
-            auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
+            auto& textureObject = GetTextureObjectByTargetForParameter(textureUploadTarget, textureTarget);
             if (!textureObject) return;
             SetTextureBorderColorFromUnsignedInts(textureObject, params);
             break;
@@ -1248,7 +1569,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             TextureTarget textureTarget = MG_Util::ConvertGLEnumToTextureTarget(target);
 
             // ======================= Processing ================================
-            auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
+            auto& textureObject = GetTextureObjectByTargetForParameter(textureUploadTarget, textureTarget);
             if (!textureObject) return;
 
             Vec4<TextureSwizzleParam> swizzleParams;
@@ -1299,6 +1620,8 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& textureObject =
             isProxy ? TextureImpl::pProxyTextureManager->CreateOrReplaceProxyTextureObject(textureUploadTarget)
                     : bindingSlot.GetBoundObject();
+        // Name 0 resolves to the target's default texture object - a real texture this call
+        // (re)specifies like any other; the slot is never empty anymore.
         if (!TextureImpl::ValidateTextureObject(textureObject)) return;
         if (textureObject->GetStorageType() != TextureStorageType::Mipmap) {
             MG_State::pGLContext->RecordError(
@@ -1340,6 +1663,8 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& textureObject =
             isProxy ? TextureImpl::pProxyTextureManager->CreateOrReplaceProxyTextureObject(textureUploadTarget)
                     : bindingSlot.GetBoundObject();
+        // Name 0 resolves to the target's default texture object - a real texture this call
+        // (re)specifies like any other; the slot is never empty anymore.
         if (!TextureImpl::ValidateTextureObject(textureObject)) return;
         if (textureObject->GetStorageType() != TextureStorageType::Mipmap) {
             MG_State::pGLContext->RecordError(
@@ -1399,6 +1724,21 @@ namespace MobileGL::MG_Impl::GLImpl {
             return;
         }
 
+        // RGTC is a 2D-only compression scheme, so a 3D target rejects it. This has to be tested on
+        // the raw enum: the RGTC formats resolve to plain R8/RG8/SNORM storage on the way in (see
+        // GLToMG's TextureEnumConverter), so once the internal format is converted there is nothing
+        // left to distinguish them from an ordinary one- or two-channel upload.
+        if ((textureUploadTarget == TextureUploadTarget::Texture3D ||
+             textureUploadTarget == TextureUploadTarget::ProxyTexture3D) &&
+            (internalformat == GL_COMPRESSED_RED_RGTC1 || internalformat == GL_COMPRESSED_SIGNED_RED_RGTC1 ||
+             internalformat == GL_COMPRESSED_RG_RGTC2 || internalformat == GL_COMPRESSED_SIGNED_RG_RGTC2)) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                             "RGTC compressed formats are invalid for 3D texture targets"));
+            return;
+        }
+
         // TODO: GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the
         // GL_PIXEL_UNPACK_BUFFER target and the buffer object's data store is currently mapped.
         // GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_BUFFER
@@ -1408,6 +1748,8 @@ namespace MobileGL::MG_Impl::GLImpl {
         // target and data is not evenly divisible into the number of bytes needed to store in memory a datum
         // indicated by type.
         // ======================= Processing ================================
+        textureInternalFormat =
+            MG_Util::ConvertInternalFormatToSized(textureInternalFormat, textureInputFormat, texturePixelDataType);
         auto& activeUnit = MG_State::pGLContext->GetTextureUnitObject(MG_State::pGLContext->GetActiveTextureUnit());
         auto& bindingSlot = activeUnit.GetBindingSlot(textureTarget);
         Bool isProxy = TextureImpl::IsProxyTextureTarget(textureUploadTarget);
@@ -1416,6 +1758,8 @@ namespace MobileGL::MG_Impl::GLImpl {
                     : bindingSlot.GetBoundObject();
 
         // ===================== Error Checking ==============================
+        // Name 0 resolves to the target's default texture object - a real texture this call
+        // (re)specifies like any other; the slot is never empty anymore.
         if (!TextureImpl::ValidateTextureObject(textureObject)) return;
         if (!ValidateTextureMutable(textureObject, __func__)) return;
 
@@ -1449,7 +1793,12 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto textureMipmapObject = static_cast<MG_State::GLState::TextureObjectMipmap*>(textureObject.get());
 
         // Allocate in TextureObject
-        textureMipmapObject->AllocateStorage(textureUploadTarget, level, {{width, height, depth}, internalBytes});
+        if (isProxy) {
+            MGLOG_D("%s: isProxy = true, not allocating", __func__);
+        } else {
+            DiscardMipmapChainOnBaseRespecification(textureMipmapObject, textureUploadTarget, level);
+            textureMipmapObject->AllocateStorage(textureUploadTarget, level, {{width, height, depth}, internalBytes});
+        }
 
         if (!originalPixels) {
             MGLOG_D("%s: No input pixel and no PBO bound, no pixel transfer", __func__);
@@ -1476,6 +1825,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         textureMipmapObject->MarkStorageDirty(textureUploadTarget, level, true);
 
         free(processedPixels);
+        MaybeAutoGenerateMipmap(target, textureObject, isProxy, level);
     }
 
     void TexImage2D_State(GLenum target, GLint level, GLint internalformat, GLsizei width, GLsizei height, GLint border,
@@ -1530,6 +1880,8 @@ namespace MobileGL::MG_Impl::GLImpl {
                     : bindingSlot.GetBoundObject();
 
         // ===================== Error Checking ==============================
+        // Name 0 resolves to the target's default texture object - a real texture this call
+        // (re)specifies like any other; the slot is never empty anymore.
         if (!TextureImpl::ValidateTextureObject(textureObject)) return;
         if (!ValidateTextureMutable(textureObject, __func__)) return;
 
@@ -1572,6 +1924,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             MGLOG_D("%s: isProxy = true, not allocating", __func__);
         } else {
             MGLOG_D("%s: Allocating %d bytes at mip %d", __func__, internalBytes, level);
+            DiscardMipmapChainOnBaseRespecification(textureMipmapObject, textureUploadTarget, level);
             textureMipmapObject->AllocateStorage(textureUploadTarget, level,
                                                  {{width, height, 1}, internalBytes});
         }
@@ -1634,6 +1987,8 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& textureObject =
             isProxy ? TextureImpl::pProxyTextureManager->CreateOrReplaceProxyTextureObject(textureUploadTarget)
                     : bindingSlot.GetBoundObject();
+        // Name 0 resolves to the target's default texture object - a real texture this call
+        // (re)specifies like any other; the slot is never empty anymore.
         if (!TextureImpl::ValidateTextureObject(textureObject)) return;
         if (!ValidateTextureMutable(textureObject, __func__)) return;
 
@@ -1658,6 +2013,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                         "Texture object here should always be an object with mipmap");
         auto textureMipmapObject = static_cast<MG_State::GLState::TextureObjectMipmap*>(textureObject.get());
         if (!isProxy) {
+            DiscardMipmapChainOnBaseRespecification(textureMipmapObject, textureUploadTarget, level);
             textureMipmapObject->AllocateStorage(textureUploadTarget, level, {{width, 1, 1}, internalBytes});
         }
 
@@ -1689,8 +2045,12 @@ namespace MobileGL::MG_Impl::GLImpl {
         if (!TextureImpl::ValidateTextureUploadTarget(textureUploadTarget)) return;
         if (!TextureImpl::ValidateTextureInternalFormat(textureInternalFormat)) return;
         // TODO: make sure `internalformat` is in one of supported format for TexBuffer
+        // GL 3.3 core 3.8.5: buffer zero detaches any buffer from the buffer texture - only a
+        // nonzero name that is not an existing buffer object is an error. This is reachable on
+        // the default buffer texture (bound whenever texture 0 is bound to GL_TEXTURE_BUFFER),
+        // which the GL CTS state reset detaches with glTexBuffer(..., 0) after every case.
         auto& bufferObject = MG_State::pGLContext->GetBufferObject(buffer);
-        if (!bufferObject) {
+        if (buffer != 0 && !bufferObject) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidOperation,
                 MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
@@ -1704,6 +2064,8 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& textureObject = bindingSlot.GetBoundObject();
 
         // ===================== Error Checking ==============================
+        // Name 0 is the default buffer texture - a real object the (de)attach operates on, not a
+        // silent no-op; the slot is never empty now that every unit/target holds its default.
         if (!TextureImpl::ValidateTextureObject(textureObject)) return;
         if (textureObject->GetStorageType() != TextureStorageType::Buffer) {
             MG_State::pGLContext->RecordError(
@@ -1724,7 +2086,9 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     GLboolean IsTexture_State(GLuint texture) {
         // ======================= Processing ================================
-        if (!TextureImpl::ValidateTextureName(texture, true)) return GL_FALSE;
+        // GL 3.3 core 6.1.4: IsTexture generates no error - an unknown, deleted or merely reserved
+        // name is just GL_FALSE. Probing with the recording validator (as every other Is* entry
+        // point already avoids doing) would leave a spurious INVALID_VALUE behind.
         return MG_State::pGLContext->ValidateTextureObject(texture) ? GL_TRUE : GL_FALSE;
     }
 
@@ -2302,7 +2666,13 @@ namespace MobileGL::MG_Impl::GLImpl {
     }
 
     void GetCompressedTexImage_State(GLenum target, GLint level, void* img) {
-        // TODO: implement
+        // TODO: implement compressed readback. Reporting success while writing nothing hands
+        // the caller stale memory with GL_NO_ERROR; no texture can be compressed yet, and GL
+        // specifies GL_INVALID_OPERATION when the bound level is not compressed.
+        MG_State::pGLContext->RecordError(
+            ErrorCode::InvalidOperation,
+            MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                         "Texture level is not stored in a compressed format."));
     }
 
     void GenTextures_State(GLsizei n, GLuint* textures) {
@@ -2489,20 +2859,20 @@ namespace MobileGL::MG_Impl::GLImpl {
     void CompressedTexSubImage3D_State(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint zoffset,
                                        GLsizei width, GLsizei height, GLsizei depth, GLenum format, GLsizei imageSize,
                                        const void* data) {
-        // TODO: implement
-        THROW_UNIMPL_EXCEPTION;
+        // TODO: implement compressed upload - see CompressedTexImage2D_State.
+        RecordUnsupportedCompressedFormat(__func__);
     }
 
     void CompressedTexSubImage2D_State(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width,
                                        GLsizei height, GLenum format, GLsizei imageSize, const void* data) {
-        // TODO: implement
-        THROW_UNIMPL_EXCEPTION;
+        // TODO: implement compressed upload - see CompressedTexImage2D_State.
+        RecordUnsupportedCompressedFormat(__func__);
     }
 
     void CompressedTexSubImage1D_State(GLenum target, GLint level, GLint xoffset, GLsizei width, GLenum format,
                                        GLsizei imageSize, const void* data) {
-        // TODO: implement
-        THROW_UNIMPL_EXCEPTION;
+        // TODO: implement compressed upload - see CompressedTexImage2D_State.
+        RecordUnsupportedCompressedFormat(__func__);
     }
 
     void CompressedTexImage3D_State(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height,
@@ -2512,8 +2882,8 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
         if (!ValidateTextureMutable(textureObject, __func__)) return;
 
-        // TODO: implement
-        THROW_UNIMPL_EXCEPTION;
+        // TODO: implement compressed upload - see CompressedTexImage2D_State.
+        RecordUnsupportedCompressedFormat(__func__);
     }
 
     void CompressedTexImage2D_State(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height,
@@ -2523,8 +2893,11 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
         if (!ValidateTextureMutable(textureObject, __func__)) return;
 
-        // TODO: implement
-        THROW_UNIMPL_EXCEPTION;
+        // TODO: implement compressed upload. Until then report the spec error for an
+        // unsupported compressed format rather than throwing - a C++ exception unwinding
+        // through the C GL ABI is a hard crash for the caller, while GL_INVALID_ENUM is
+        // exactly what GL_NUM_COMPRESSED_TEXTURE_FORMATS == 0 promises.
+        RecordUnsupportedCompressedFormat(__func__);
     }
 
     void CompressedTexImage1D_State(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLint border,
@@ -2534,8 +2907,8 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& textureObject = GetTextureObjectByTarget(textureUploadTarget, textureTarget);
         if (!ValidateTextureMutable(textureObject, __func__)) return;
 
-        // TODO: implement
-        THROW_UNIMPL_EXCEPTION;
+        // TODO: implement compressed upload - see CompressedTexImage2D_State.
+        RecordUnsupportedCompressedFormat(__func__);
     }
 
     void BindTexture_State(GLenum target, GLuint texture) {
@@ -2547,11 +2920,13 @@ namespace MobileGL::MG_Impl::GLImpl {
         // ===================== Error Checking ==============================
         if (!TextureImpl::ValidateTextureTarget(textureTarget)) return;
 
-        // Name 0 unbinds the current target from the active texture unit.
+        // GL 3.3 core 3.8: name 0 is the target's default texture object - a real texture that
+        // glTexImage*/glTexParameter*/glGetTex* must operate on - not "nothing bound". Binding it
+        // restores the unit/target slot to its initial state.
         if (texture == 0) {
             auto& currentUnit = MG_State::pGLContext->GetTextureUnitObject(activeUnit);
             auto& bindingSlot = currentUnit.GetBindingSlot(textureTarget);
-            bindingSlot.Bind(nullptr);
+            bindingSlot.Bind(MG_State::pGLContext->GetDefaultTextureObject(textureTarget));
             MG_State::pGLContext->NoteTextureUnitTouched(activeUnit);
             return;
         }
@@ -2563,7 +2938,15 @@ namespace MobileGL::MG_Impl::GLImpl {
             return;
         }
 
-        if (!TextureImpl::ValidateTextureName(texture)) return;
+        // GL 3.3 core 3.8.1: a name that GenTextures never returned - or that has since been deleted -
+        // is not a legal bind target in the core profile (no application-generated names), and the error
+        // is INVALID_OPERATION, not INVALID_VALUE.
+        if (!MG_State::pGLContext->ValidateTextureName(texture)) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "BindTexture_State", "Invalid texture name"));
+            return;
+        }
 
         // ======================= Processing ================================
         Bool doesTextureExist = MG_State::pGLContext->ValidateTextureObject(texture);
@@ -2584,14 +2967,25 @@ namespace MobileGL::MG_Impl::GLImpl {
 
     void ActiveTexture_State(GLenum texture) {
         // ===================== Error Checking ==============================
-        if (texture < GL_TEXTURE0 || texture > GL_TEXTURE31) {
+        // GL 3.3 core 3.8: the valid range is [GL_TEXTURE0, GL_TEXTURE0 +
+        // GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS) - NOT a fixed 0..31 range. GL CTS's per-case
+        // state reset iterates every advertised combined unit, so rejecting units the
+        // implementation itself reports would leave a sticky GL_INVALID_ENUM behind and abort
+        // whole test batches. The backend already clamps its advertised value to the state
+        // layer's MAX_TEXTURE_IMAGE_UNITS capacity.
+        Int maxCombinedUnits = static_cast<Int>(MG_State::GLState::TextureState::MAX_TEXTURE_IMAGE_UNITS);
+        if (MG_Backend::pActiveBackendObject) {
+            maxCombinedUnits = std::min(
+                maxCombinedUnits, MG_Backend::pActiveBackendObject->GetDynamicParameters().MaxCombinedTextureImageUnits);
+        }
+        if (texture < GL_TEXTURE0 || static_cast<Int>(texture - GL_TEXTURE0) >= maxCombinedUnits) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidEnum,
                 MakeUnique<GenericErrorInfo>(
                     "MG_Impl/GLImpl", "ActiveTexture_State",
-                    std::format("Texture must be one of GL_TEXTUREi, where i is in the range 0 to 31, but got "
+                    std::format("Texture must be one of GL_TEXTUREi, where i is in the range 0 to {}, but got "
                                 "invalid enum: 0x{:X}, which may stand for unit {}.",
-                                texture, texture - GL_TEXTURE0)));
+                                maxCombinedUnits - 1, texture, texture - GL_TEXTURE0)));
             return;
         }
 
@@ -2860,6 +3254,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             textureMipmapObject->AllocateStorage(textureUploadTarget, level, {{levelWidth, 1, 1}, byteSize});
             textureMipmapObject->MarkStorageDirty(textureUploadTarget, level, false);
         }
+        // Immutable storage defines exactly `levels` levels; AllocateStorage only grows, so a
+        // longer pre-existing chain has to be dropped explicitly.
+        textureMipmapObject->TruncateMipmapLevels(textureUploadTarget, static_cast<Uint>(levels));
         textureObject->SetImmutableLevels(static_cast<Uint>(levels));
     }
 
@@ -2912,6 +3309,8 @@ namespace MobileGL::MG_Impl::GLImpl {
             textureMipmapObject->AllocateStorage(textureUploadTarget, level, {{levelWidth, levelHeight, 1}, byteSize});
             textureMipmapObject->MarkStorageDirty(textureUploadTarget, level, false);
         }
+        // See TextureStorage1D.
+        textureMipmapObject->TruncateMipmapLevels(textureUploadTarget, static_cast<Uint>(levels));
         textureObject->SetImmutableLevels(static_cast<Uint>(levels));
     }
 
@@ -2951,16 +3350,21 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto* textureMipmapObject = static_cast<MG_State::GLState::TextureObjectMipmap*>(textureObject.get());
 
         textureObject->SetInternalFormat(textureInternalFormat);
+        // Array targets keep their layer count constant across levels; only true 3D
+        // textures halve depth per level (GL 3.3 §3.9 glTexStorage3D).
+        const Bool depthMips = DepthParticipatesInMipmapping(textureObject->GetTarget());
         for (GLsizei level = 0; level < levels; ++level) {
             const GLsizei levelWidth = std::max<GLsizei>(1, width >> level);
             const GLsizei levelHeight = std::max<GLsizei>(1, height >> level);
-            const GLsizei levelDepth = std::max<GLsizei>(1, depth >> level);
+            const GLsizei levelDepth = depthMips ? std::max<GLsizei>(1, depth >> level) : depth;
             const SizeT byteSize = ComputeTextureStorageByteSize(textureInternalFormat, levelWidth, levelHeight,
                                                                  levelDepth);
             textureMipmapObject->AllocateStorage(textureUploadTarget, level,
                                                  {{levelWidth, levelHeight, levelDepth}, byteSize});
             textureMipmapObject->MarkStorageDirty(textureUploadTarget, level, false);
         }
+        // See TextureStorage1D.
+        textureMipmapObject->TruncateMipmapLevels(textureUploadTarget, static_cast<Uint>(levels));
         textureObject->SetImmutableLevels(static_cast<Uint>(levels));
     }
 
@@ -2990,6 +3394,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& bindingSlot = activeUnit.GetBindingSlot(textureTarget);
         auto& textureObject = bindingSlot.GetBoundObject();
         if (!TextureImpl::ValidateTextureObject(textureObject)) return;
+        if (!TextureImpl::ValidateTextureNotDefault(textureObject, __func__)) return;
 
         TextureStorage1D(textureObject->GetExternalIndex(), levels, internalformat, width);
     }
@@ -3004,6 +3409,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& bindingSlot = activeUnit.GetBindingSlot(textureTarget);
         auto& textureObject = bindingSlot.GetBoundObject();
         if (!TextureImpl::ValidateTextureObject(textureObject)) return;
+        if (!TextureImpl::ValidateTextureNotDefault(textureObject, __func__)) return;
 
         TextureStorage2D(textureObject->GetExternalIndex(), levels, internalformat, width, height);
     }
@@ -3019,6 +3425,7 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& bindingSlot = activeUnit.GetBindingSlot(textureTarget);
         auto& textureObject = bindingSlot.GetBoundObject();
         if (!TextureImpl::ValidateTextureObject(textureObject)) return;
+        if (!TextureImpl::ValidateTextureNotDefault(textureObject, __func__)) return;
 
         TextureStorage3D(textureObject->GetExternalIndex(), levels, internalformat, width, height, depth);
     }
@@ -3174,8 +3581,10 @@ namespace MobileGL::MG_Impl::GLImpl {
         auto& textureUnit = MG_State::pGLContext->GetTextureUnitObject(static_cast<Int>(unit));
         MG_State::pGLContext->NoteTextureUnitTouched(static_cast<Int>(unit));
         if (texture == 0) {
+            // GL 4.5 8.1: texture zero unbinds every target of the unit, i.e. rebinds each
+            // target's default texture object (the unit's initial state).
             for (auto& slot : textureUnit.GetAllBindingSlots()) {
-                slot.Bind(nullptr);
+                slot.Bind(MG_State::pGLContext->GetDefaultTextureObject(slot.GetTarget()));
             }
             return;
         }
@@ -3714,6 +4123,27 @@ namespace MobileGL::MG_Impl::GLImpl {
         CopyTexSubImage2D_Backend(target, level, xoffset, yoffset, x, y, width, height);
     }
 
+    void CopyTextureSubImage2D(GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y,
+                               GLsizei width, GLsizei height) {
+        auto textureObject = GetTextureObjectByName(texture, __func__);
+        if (!textureObject) return;
+        // GL 4.6 sec. 8.8: the 2D form only accepts these effective targets; cube maps must
+        // go through CopyTextureSubImage3D with the face as a layer.
+        const auto target = textureObject->GetTarget();
+        if (target != TextureTarget::Texture2D && target != TextureTarget::Texture1DArray &&
+            target != TextureTarget::TextureRectangle) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                             "CopyTextureSubImage2D requires a 2D, 1D-array, or "
+                                             "rectangle texture."));
+            return;
+        }
+        WithTemporarilyBoundNamedTexture(textureObject, [&](GLenum glTarget) {
+            CopyTexSubImage2D_Backend(glTarget, level, xoffset, yoffset, x, y, width, height);
+        });
+    }
+
     void CopyTexSubImage1D(GLenum target, GLint level, GLint xoffset, GLint x, GLint y, GLsizei width) {
         CopyTexSubImage1D_State(target, level, xoffset, x, y, width);
     }

MobileGL/MG_Impl/GLImpl/Texture/GL_Texture.h

@@ -11,6 +11,9 @@
 
 namespace MobileGL::MG_Impl::GLImpl {
     /* @INSERTION_POINT:FUNCTION_DECLARATION@ */
+    void ClearTexImage(GLuint texture, GLint level, GLenum format, GLenum type, const void* data);
+    void ClearTexSubImage(GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint zoffset, GLsizei width,
+                          GLsizei height, GLsizei depth, GLenum format, GLenum type, const void* data);
     void BindImageTexture(GLuint unit, GLuint texture, GLint level, GLboolean layered, GLint layer, GLenum access,
                           GLenum format);
     void GenerateMipmap(GLenum target);
@@ -95,6 +98,8 @@ namespace MobileGL::MG_Impl::GLImpl {
                            GLsizei width, GLsizei height);
     void CopyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width,
                            GLsizei height);
+    void CopyTextureSubImage2D(GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y,
+                               GLsizei width, GLsizei height);
     void CopyTexSubImage1D(GLenum target, GLint level, GLint xoffset, GLint x, GLint y, GLsizei width);
     void CopyTexImage2D(GLenum target, GLint level, GLenum internalformat, GLint x, GLint y, GLsizei width,
                         GLsizei height, GLint border);

MobileGL/MG_Impl/GLImpl/Texture/ProxyTexture.cpp

@@ -14,7 +14,8 @@
 #include <MG_State/GLState/TextureState/TextureObjectStubs.h>
 
 namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
-    UniquePtr<ProxyTextureManager> pProxyTextureManager;
+    // Leak-at-exit storage; see GlobalObjects.cpp.
+    UniquePtr<ProxyTextureManager>& pProxyTextureManager = *new UniquePtr<ProxyTextureManager>();
 
     Bool IsProxyTextureTarget(TextureUploadTarget target) {
         switch (target) {

MobileGL/MG_Impl/GLImpl/Texture/ProxyTexture.h

@@ -23,5 +23,5 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
         UnorderedMap<TextureUploadTarget, SharedPtr<MG_State::GLState::ITextureObject>> m_proxyTexturesMap;
     };
 
-    extern UniquePtr<ProxyTextureManager> pProxyTextureManager;
+    extern UniquePtr<ProxyTextureManager>& pProxyTextureManager;
 } // namespace MobileGL::MG_Impl::GLImpl::TextureImpl

MobileGL/MG_Impl/GLImpl/Texture/Validators.cpp

@@ -175,13 +175,15 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
         return true;
     }
 
-    static Bool IsIntegerColorInputFormat(TextureInputFormat format) {
+    Bool IsIntegerColorInputFormat(TextureInputFormat format) {
         return format == TextureInputFormat::RInteger || format == TextureInputFormat::RGInteger ||
                format == TextureInputFormat::RGBInteger || format == TextureInputFormat::BGRInteger ||
-               format == TextureInputFormat::RGBAInteger || format == TextureInputFormat::BGRAInteger;
+               format == TextureInputFormat::RGBAInteger || format == TextureInputFormat::BGRAInteger ||
+               format == TextureInputFormat::GreenInteger || format == TextureInputFormat::BlueInteger ||
+               format == TextureInputFormat::AlphaInteger;
     }
 
-    static Bool IsIntegerColorInternalFormat(TextureInternalFormat internalFormat) {
+    Bool IsIntegerColorInternalFormat(TextureInternalFormat internalFormat) {
         switch (internalFormat) {
             case TextureInternalFormat::R8I:
             case TextureInternalFormat::R8UI:
@@ -235,17 +237,15 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
                format == TextureInputFormat::StencilIndex;
     }
 
-    // Mirrors the desktop-GL validity matrix used by GL CTS packed_pixels (glcPackedPixelsTests
-    // isFormatValid, INPUT_TEXIMAGE): packed-type/format pairing, depth-vs-color mismatch, and
-    // integer-ness matching all raise GL_INVALID_OPERATION instead of reaching the upload path.
-    Bool ValidateTextureInternalFormatCompatibleWithInput(TextureInputFormat format,
-                                                          TextureInternalFormat internalFormat,
-                                                          TexturePixelDataType type) {
+    // Client-memory format<->type pairing rules shared by pixel uploads (TexImage*) and readbacks
+    // (ReadPixels, GetTexImage). Mirrors the desktop-GL validity matrix used by GL CTS packed_pixels
+    // (glcPackedPixelsTests isFormatValid): packed types constrain the formats they may pair with, and
+    // integer formats reject floating-point types; violations raise GL_INVALID_OPERATION.
+    Bool ValidateClientFormatTypePairing(TextureInputFormat format, TexturePixelDataType type) {
         const auto recordInvalidOperation = [](const char* message) {
             MG_State::pGLContext->RecordError(
                 ErrorCode::InvalidOperation,
-                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "ValidateTextureInternalFormatCompatibleWithInput",
-                                             message));
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "ValidateClientFormatTypePairing", message));
             return false;
         };
 
@@ -288,6 +288,27 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
             return recordInvalidOperation("Integer format cannot be used with a floating-point type");
         }
 
+        return true;
+    }
+
+    // Mirrors the desktop-GL validity matrix used by GL CTS packed_pixels (glcPackedPixelsTests
+    // isFormatValid, INPUT_TEXIMAGE): packed-type/format pairing, depth-vs-color mismatch, and
+    // integer-ness matching all raise GL_INVALID_OPERATION instead of reaching the upload path.
+    Bool ValidateTextureInternalFormatCompatibleWithInput(TextureInputFormat format,
+                                                          TextureInternalFormat internalFormat,
+                                                          TexturePixelDataType type) {
+        const auto recordInvalidOperation = [](const char* message) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", "ValidateTextureInternalFormatCompatibleWithInput",
+                                             message));
+            return false;
+        };
+
+        if (!ValidateClientFormatTypePairing(format, type)) {
+            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");
@@ -339,6 +360,19 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
         return true;
     }
 
+    Bool ValidateTextureNotDefault(const SharedPtr<MG_State::GLState::ITextureObject>& textureObject,
+                                   const char* caller) {
+        if (textureObject && textureObject->GetExternalIndex() == 0) {
+            MG_State::pGLContext->RecordError(
+                ErrorCode::InvalidOperation,
+                MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", caller,
+                                             "This operation is not allowed on the default texture (zero is "
+                                             "bound to the target)."));
+            return false;
+        }
+        return true;
+    }
+
     Bool ValidateTextureTargetUniformity(SharedPtr<MG_State::GLState::ITextureObject> textureObject,
                                          TextureTarget target) {
         if (!textureObject) return true; // should be created later

MobileGL/MG_Impl/GLImpl/Texture/Validators.h

@@ -23,11 +23,19 @@ namespace MobileGL::MG_Impl::GLImpl::TextureImpl {
     Bool ValidateTextureSizeRange(Int width, Int height, Int depth);
     Bool ValidateTextureInternalFormat(TextureInternalFormat format);
     Bool ValidateTextureBorderNumber(Int border);
+    Bool IsIntegerColorInputFormat(TextureInputFormat format);
+    Bool IsIntegerColorInternalFormat(TextureInternalFormat internalFormat);
+    Bool ValidateClientFormatTypePairing(TextureInputFormat format, TexturePixelDataType type);
     Bool ValidateTextureInternalFormatCompatibleWithInput(TextureInputFormat format,
                                                           TextureInternalFormat internalFormat,
                                                           TexturePixelDataType type);
     Bool ValidateTextureLevelWithUploadTarget(TextureUploadTarget target, Int level);
     Bool ValidateTextureObject(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
+    // error is generated if zero is bound to target", ARB_texture_storage).
+    Bool ValidateTextureNotDefault(const SharedPtr<MG_State::GLState::ITextureObject>& textureObject,
+                                   const char* caller);
     Bool ValidateTextureTargetUniformity(SharedPtr<MG_State::GLState::ITextureObject> textureObject,
                                          TextureTarget target);
     Bool ValidateTextureSubImageOffsets(SharedPtr<MG_State::GLState::ITextureObject> textureObject, Int xoffset,

MobileGL/MG_Impl/GLImpl/VertexArray/GL_VertexArray.cpp

@@ -78,15 +78,12 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
 
         static bool ValidateCurrentVertexAttribIndex(GLuint index, const char* funcName) {
-            if (!VertexArrayImpl::ValidateVertexAttributeIndex(index)) return false;
-            if (index == 0) {
-                MG_State::pGLContext->RecordError(
-                    ErrorCode::InvalidOperation,
-                    MakeUnique<GenericErrorInfo>("MG_Impl/GLImpl", funcName,
-                                                 "Generic vertex attribute 0 current value cannot be modified."));
-                return false;
-            }
-            return true;
+            // GL 3.3 core 2.7: VertexAttrib* sets the current value of ANY generic attribute,
+            // including index 0 - only an out-of-range index is an error (INVALID_VALUE).
+            // "Attribute 0 is immutable" was legacy immediate-mode lore; rejecting it broke GL
+            // CTS's per-case state reset, which writes vertexAttrib4f(0, 0,0,0,1) after every case.
+            static_cast<void>(funcName);
+            return VertexArrayImpl::ValidateVertexAttributeIndex(index);
         }
 
         static bool TryGetVertexAttribute(GLuint index, const MG_State::GLState::VertexAttribute** outAttr) {
@@ -288,7 +285,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             GLuint vao = arrays[i];
             if (vao == 0) continue;
 
-            if (!VertexArrayImpl::ValidateVertexArrayName(vao)) continue;
+            // GL 3.3 core 2.10: unknown names are silently ignored on delete; the shared bind-path
+            // validator would record INVALID_OPERATION instead.
+            if (!MG_State::pGLContext->ValidateVertexArrayName(vao)) continue;
 
             if (MG_State::pGLContext->GetBoundVertexArray() &&
                 MG_State::pGLContext->GetBoundVertexArray() == MG_State::pGLContext->GetVertexArrayObject(vao)) {

MobileGL/MG_Impl/WGLImpl/Exporting/Definitions.cpp

@@ -0,0 +1,156 @@
+// MobileGL - MobileGL/MG_Impl/WGLImpl/Exporting/Definitions.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
+
+// wingdi.h declares most wgl* entry points as WINGDIAPI (__declspec(dllimport)),
+// which would reject our definitions. _GDI32_ is the SDK's "I am the module that
+// implements these" switch: it turns WINGDIAPI into a plain declaration. It must
+// be defined before the first windows.h inclusion in this translation unit.
+#if defined(_WIN32) && !defined(_GDI32_)
+#define _GDI32_ 1
+#endif
+
+#include <Includes.h>
+
+#if defined(_WIN32)
+#include "../WGLImpl.h"
+
+namespace WGL = MobileGL::MG_Impl::WGLImpl;
+
+// ---- Pixel-format entry points (gdi32 forwards ChoosePixelFormat/SetPixelFormat/
+// ---- DescribePixelFormat/GetPixelFormat/SwapBuffers into these exports) ----
+
+extern "C" int WINAPI wglChoosePixelFormat(HDC hdc, CONST PIXELFORMATDESCRIPTOR* ppfd) {
+    return WGL::ChoosePixelFormat(hdc, ppfd);
+}
+
+extern "C" int WINAPI wglDescribePixelFormat(HDC hdc, int iPixelFormat, UINT nBytes,
+                                                   LPPIXELFORMATDESCRIPTOR ppfd) {
+    return WGL::DescribePixelFormat(hdc, iPixelFormat, nBytes, ppfd);
+}
+
+extern "C" int WINAPI wglGetPixelFormat(HDC hdc) {
+    return WGL::GetPixelFormat(hdc);
+}
+
+extern "C" BOOL WINAPI wglSetPixelFormat(HDC hdc, int iPixelFormat, CONST PIXELFORMATDESCRIPTOR* ppfd) {
+    return WGL::SetPixelFormat(hdc, iPixelFormat, ppfd);
+}
+
+extern "C" BOOL WINAPI wglSwapBuffers(HDC hdc) {
+    return WGL::SwapBuffers(hdc);
+}
+
+// ---- Context management ----
+
+extern "C" HGLRC WINAPI wglCreateContext(HDC hdc) {
+    return WGL::CreateContext(hdc);
+}
+
+extern "C" HGLRC WINAPI wglCreateLayerContext(HDC hdc, int iLayerPlane) {
+    return iLayerPlane == 0 ? WGL::CreateContext(hdc) : nullptr;
+}
+
+extern "C" BOOL WINAPI wglCopyContext(HGLRC, HGLRC, UINT) {
+    MGLOG_W("wglCopyContext is not supported");
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return FALSE;
+}
+
+extern "C" BOOL WINAPI wglDeleteContext(HGLRC hglrc) {
+    return WGL::DeleteContext(hglrc);
+}
+
+extern "C" HGLRC WINAPI wglGetCurrentContext(VOID) {
+    return WGL::GetCurrentContext();
+}
+
+extern "C" HDC WINAPI wglGetCurrentDC(VOID) {
+    return WGL::GetCurrentDC();
+}
+
+extern "C" BOOL WINAPI wglMakeCurrent(HDC hdc, HGLRC hglrc) {
+    return WGL::MakeCurrent(hdc, hglrc);
+}
+
+extern "C" BOOL WINAPI wglShareLists(HGLRC hglrcShare, HGLRC hglrcDest) {
+    return WGL::ShareLists(hglrcShare, hglrcDest);
+}
+
+// ---- Proc address ----
+
+extern "C" PROC WINAPI wglGetProcAddress(LPCSTR lpszProc) {
+    return WGL::GetProcAddress(lpszProc);
+}
+
+extern "C" PROC WINAPI wglGetDefaultProcAddress(LPCSTR lpszProc) {
+    return WGL::GetProcAddress(lpszProc);
+}
+
+// ---- Layer planes and palettes (unsupported; overlay planes do not exist here) ----
+
+extern "C" BOOL WINAPI wglDescribeLayerPlane(HDC, int, int, UINT, LPLAYERPLANEDESCRIPTOR) {
+    return FALSE;
+}
+
+extern "C" int WINAPI wglSetLayerPaletteEntries(HDC, int, int, int, CONST COLORREF*) {
+    return 0;
+}
+
+extern "C" int WINAPI wglGetLayerPaletteEntries(HDC, int, int, int, COLORREF*) {
+    return 0;
+}
+
+extern "C" BOOL WINAPI wglRealizeLayerPalette(HDC, int, BOOL) {
+    return FALSE;
+}
+
+extern "C" BOOL WINAPI wglSwapLayerBuffers(HDC hdc, UINT fuPlanes) {
+    if (fuPlanes & WGL_SWAP_MAIN_PLANE) {
+        return WGL::SwapBuffers(hdc);
+    }
+    return FALSE;
+}
+
+extern "C" DWORD WINAPI wglSwapMultipleBuffers(UINT n, CONST WGLSWAP* ps) {
+    if (!ps) {
+        return 0;
+    }
+    DWORD swapped = 0;
+    for (UINT i = 0; i < n; ++i) {
+        if (WGL::SwapBuffers(ps[i].hdc)) {
+            ++swapped;
+        }
+    }
+    return swapped;
+}
+
+// ---- Font rendering (legacy immediate-mode feature; not supported) ----
+
+extern "C" BOOL WINAPI wglUseFontBitmapsA(HDC, DWORD, DWORD, DWORD) {
+    MGLOG_W("wglUseFontBitmapsA is not supported");
+    return FALSE;
+}
+
+extern "C" BOOL WINAPI wglUseFontBitmapsW(HDC, DWORD, DWORD, DWORD) {
+    MGLOG_W("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");
+    return FALSE;
+}
+
+extern "C" BOOL WINAPI wglUseFontOutlinesW(HDC, DWORD, DWORD, DWORD, FLOAT, FLOAT, int,
+                                                 LPGLYPHMETRICSFLOAT) {
+    MGLOG_W("wglUseFontOutlinesW is not supported");
+    return FALSE;
+}
+
+#endif // _WIN32

MobileGL/MG_Impl/WGLImpl/Exporting/wgl.def

@@ -0,0 +1,30 @@
+; MobileGL WGL exports. The wgl* entry points are defined without
+; __declspec(dllexport) because wingdi.h pre-declares them (with _GDI32_ they
+; become plain declarations, and MSVC rejects adding dllexport afterwards),
+; so this .def file is what actually exports them from the DLL.
+EXPORTS
+    wglChoosePixelFormat
+    wglCopyContext
+    wglCreateContext
+    wglCreateLayerContext
+    wglDeleteContext
+    wglDescribeLayerPlane
+    wglDescribePixelFormat
+    wglGetCurrentContext
+    wglGetCurrentDC
+    wglGetDefaultProcAddress
+    wglGetLayerPaletteEntries
+    wglGetPixelFormat
+    wglGetProcAddress
+    wglMakeCurrent
+    wglRealizeLayerPalette
+    wglSetLayerPaletteEntries
+    wglSetPixelFormat
+    wglShareLists
+    wglSwapBuffers
+    wglSwapLayerBuffers
+    wglSwapMultipleBuffers
+    wglUseFontBitmapsA
+    wglUseFontBitmapsW
+    wglUseFontOutlinesA
+    wglUseFontOutlinesW

MobileGL/MG_Impl/WGLImpl/WGLImpl.cpp

@@ -0,0 +1,732 @@
+// MobileGL - MobileGL/MG_Impl/WGLImpl/WGLImpl.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
+
+#include "WGLImpl.h"
+
+#if defined(_WIN32)
+#include "../EGLImpl/EGLImpl.h"
+#include "../GetProcAddress.h"
+#include <Init.h>
+
+namespace MobileGL::MG_Impl::WGLImpl {
+    namespace {
+        // WGL_ARB_pixel_format
+        constexpr int WGL_NUMBER_PIXEL_FORMATS_ARB = 0x2000;
+        constexpr int WGL_DRAW_TO_WINDOW_ARB = 0x2001;
+        constexpr int WGL_DRAW_TO_BITMAP_ARB = 0x2002;
+        constexpr int WGL_ACCELERATION_ARB = 0x2003;
+        constexpr int WGL_NEED_PALETTE_ARB = 0x2004;
+        constexpr int WGL_NEED_SYSTEM_PALETTE_ARB = 0x2005;
+        constexpr int WGL_SWAP_LAYER_BUFFERS_ARB = 0x2006;
+        constexpr int WGL_SWAP_METHOD_ARB = 0x2007;
+        constexpr int WGL_NUMBER_OVERLAYS_ARB = 0x2008;
+        constexpr int WGL_NUMBER_UNDERLAYS_ARB = 0x2009;
+        constexpr int WGL_TRANSPARENT_ARB = 0x200A;
+        constexpr int WGL_SHARE_DEPTH_ARB = 0x200C;
+        constexpr int WGL_SHARE_STENCIL_ARB = 0x200D;
+        constexpr int WGL_SHARE_ACCUM_ARB = 0x200E;
+        constexpr int WGL_SUPPORT_GDI_ARB = 0x200F;
+        constexpr int WGL_SUPPORT_OPENGL_ARB = 0x2010;
+        constexpr int WGL_DOUBLE_BUFFER_ARB = 0x2011;
+        constexpr int WGL_STEREO_ARB = 0x2012;
+        constexpr int WGL_PIXEL_TYPE_ARB = 0x2013;
+        constexpr int WGL_COLOR_BITS_ARB = 0x2014;
+        constexpr int WGL_RED_BITS_ARB = 0x2015;
+        constexpr int WGL_RED_SHIFT_ARB = 0x2016;
+        constexpr int WGL_GREEN_BITS_ARB = 0x2017;
+        constexpr int WGL_GREEN_SHIFT_ARB = 0x2018;
+        constexpr int WGL_BLUE_BITS_ARB = 0x2019;
+        constexpr int WGL_BLUE_SHIFT_ARB = 0x201A;
+        constexpr int WGL_ALPHA_BITS_ARB = 0x201B;
+        constexpr int WGL_ALPHA_SHIFT_ARB = 0x201C;
+        constexpr int WGL_ACCUM_BITS_ARB = 0x201D;
+        constexpr int WGL_ACCUM_RED_BITS_ARB = 0x201E;
+        constexpr int WGL_ACCUM_GREEN_BITS_ARB = 0x201F;
+        constexpr int WGL_ACCUM_BLUE_BITS_ARB = 0x2020;
+        constexpr int WGL_ACCUM_ALPHA_BITS_ARB = 0x2021;
+        constexpr int WGL_DEPTH_BITS_ARB = 0x2022;
+        constexpr int WGL_STENCIL_BITS_ARB = 0x2023;
+        constexpr int WGL_AUX_BUFFERS_ARB = 0x2024;
+        constexpr int WGL_NO_ACCELERATION_ARB = 0x2025;
+        constexpr int WGL_FULL_ACCELERATION_ARB = 0x2027;
+        constexpr int WGL_SWAP_EXCHANGE_ARB = 0x2028;
+        constexpr int WGL_TYPE_RGBA_ARB = 0x202B;
+        // WGL_ARB_multisample
+        constexpr int WGL_SAMPLE_BUFFERS_ARB = 0x2041;
+        constexpr int WGL_SAMPLES_ARB = 0x2042;
+        // WGL_ARB_create_context / _profile / _no_error
+        constexpr int WGL_CONTEXT_MAJOR_VERSION_ARB = 0x2091;
+        constexpr int WGL_CONTEXT_MINOR_VERSION_ARB = 0x2092;
+        constexpr int WGL_CONTEXT_LAYER_PLANE_ARB = 0x2093;
+        constexpr int WGL_CONTEXT_FLAGS_ARB = 0x2094;
+        constexpr int WGL_CONTEXT_PROFILE_MASK_ARB = 0x9126;
+        constexpr int WGL_CONTEXT_DEBUG_BIT_ARB = 0x0001;
+        constexpr int WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB = 0x0002;
+        constexpr int WGL_CONTEXT_CORE_PROFILE_BIT_ARB = 0x00000001;
+        constexpr int WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB = 0x00000002;
+        constexpr int WGL_CONTEXT_OPENGL_NO_ERROR_ARB = 0x31B3;
+        constexpr DWORD ERROR_INVALID_VERSION_ARB = 0x2095;
+        constexpr DWORD ERROR_INVALID_PROFILE_ARB = 0x2096;
+
+        struct PixelFormatInfo {
+            GLint AlphaBits;
+            GLint DepthBits;
+            GLint StencilBits;
+        };
+
+        // Mirrors the two EGLState configs (RGBA8 + depth24, stencil 8 / stencil 0).
+        constexpr PixelFormatInfo kPixelFormats[] = {
+            {8, 24, 8},
+            {8, 24, 0},
+        };
+        constexpr int kPixelFormatCount = static_cast<int>(std::size(kPixelFormats));
+
+        struct ContextObject {
+            EGLDisplay Display = EGL_NO_DISPLAY;
+            EGLConfig Config = nullptr;
+            EGLContext Context = EGL_NO_CONTEXT;
+        };
+
+        struct WindowSurface {
+            EGLDisplay Display = EGL_NO_DISPLAY;
+            EGLSurface Surface = EGL_NO_SURFACE;
+            Uint32 Width = 0;
+            Uint32 Height = 0;
+        };
+
+        std::recursive_mutex& RegistryMutex() {
+            static auto* mutex = new std::recursive_mutex();
+            return *mutex;
+        }
+
+        UnorderedMap<HGLRC, ContextObject>& Contexts() {
+            static auto* contexts = new UnorderedMap<HGLRC, ContextObject>();
+            return *contexts;
+        }
+
+        UnorderedMap<HWND, WindowSurface>& WindowSurfaces() {
+            static auto* surfaces = new UnorderedMap<HWND, WindowSurface>();
+            return *surfaces;
+        }
+
+        UnorderedMap<HWND, int>& WindowPixelFormats() {
+            static auto* formats = new UnorderedMap<HWND, int>();
+            return *formats;
+        }
+
+        Uint64& NextContextHandle() {
+            static auto* handle = new Uint64(0x10000);
+            return *handle;
+        }
+
+        struct ThreadCurrent {
+            HDC DC = nullptr;
+            HGLRC Context = nullptr;
+        };
+        thread_local ThreadCurrent t_current;
+
+        Int& SwapIntervalShadow() {
+            static auto* interval = new Int(1);
+            return *interval;
+        }
+
+        void EnsureInitialized() {
+            // Initialize() loads backend libraries and glslang, which must not run
+            // under the loader lock; first WGL call is the earliest safe moment.
+            // MobileGL::EnsureInitialized (not a local once_flag) so a fresh init
+            // can follow a full teardown from the last eglTerminate.
+            MobileGL::EnsureInitialized();
+        }
+
+        EGLDisplay EnsureDisplay() {
+            EnsureInitialized();
+            EGLDisplay display = EGLImpl::GetDisplay(EGL_DEFAULT_DISPLAY);
+            if (display == EGL_NO_DISPLAY) {
+                return EGL_NO_DISPLAY;
+            }
+            if (!EGLImpl::Initialize(display, nullptr, nullptr)) {
+                return EGL_NO_DISPLAY;
+            }
+            return display;
+        }
+
+        HGLRC EncodeContext(Uint64 handle) {
+            return reinterpret_cast<HGLRC>(static_cast<SizeT>(handle));
+        }
+
+        ContextObject* TryGetContext(HGLRC hglrc) {
+            auto& contexts = Contexts();
+            auto it = contexts.find(hglrc);
+            return it == contexts.end() ? nullptr : &it->second;
+        }
+
+        const PixelFormatInfo& PixelFormatForWindow(HWND hwnd) {
+            auto& formats = WindowPixelFormats();
+            auto it = formats.find(hwnd);
+            int index = it == formats.end() ? 1 : it->second;
+            if (index < 1 || index > kPixelFormatCount) {
+                index = 1;
+            }
+            return kPixelFormats[index - 1];
+        }
+
+        Bool QueryClientSize(HWND hwnd, Uint32& width, Uint32& height) {
+            RECT rect{};
+            if (!GetClientRect(hwnd, &rect)) {
+                return false;
+            }
+            width = static_cast<Uint32>(std::max<LONG>(rect.right - rect.left, 1));
+            height = static_cast<Uint32>(std::max<LONG>(rect.bottom - rect.top, 1));
+            return true;
+        }
+
+        // The backends never query the HWND client size themselves; the WGL layer
+        // owns size discovery and pushes changes through the internal resize hook
+        // (same contract as the macOS CGL layer).
+        void SyncSurfaceSize(HWND hwnd, WindowSurface& surface) {
+            Uint32 width = 0;
+            Uint32 height = 0;
+            if (!QueryClientSize(hwnd, width, height)) {
+                return;
+            }
+            if (width == surface.Width && height == surface.Height) {
+                return;
+            }
+            if (EGLImpl::ResizePlatformWindowSurface(surface.Display, surface.Surface,
+                                                     static_cast<EGLint>(width), static_cast<EGLint>(height))) {
+                surface.Width = width;
+                surface.Height = height;
+            }
+        }
+
+        WindowSurface* EnsureWindowSurface(HWND hwnd, const ContextObject& context) {
+            auto& surfaces = WindowSurfaces();
+            auto it = surfaces.find(hwnd);
+            if (it != surfaces.end()) {
+                SyncSurfaceSize(hwnd, it->second);
+                return &it->second;
+            }
+
+            Uint32 width = 0;
+            Uint32 height = 0;
+            if (!QueryClientSize(hwnd, width, height)) {
+                MGLOG_E("wgl: GetClientRect failed for HWND %p", hwnd);
+                return nullptr;
+            }
+
+            const EGLAttrib attribs[] = {
+                EGL_WIDTH, static_cast<EGLAttrib>(width),
+                EGL_HEIGHT, static_cast<EGLAttrib>(height),
+                EGL_NONE,
+            };
+            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);
+                return nullptr;
+            }
+
+            WindowSurface record;
+            record.Display = context.Display;
+            record.Surface = surface;
+            record.Width = width;
+            record.Height = height;
+            auto [inserted, _] = surfaces.emplace(hwnd, record);
+            return &inserted->second;
+        }
+
+        HGLRC CreateContextFromEGLAttribs(HDC hdc, HGLRC share, const EGLint* contextAttribs) {
+            const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
+            EGLDisplay display = EnsureDisplay();
+            if (display == EGL_NO_DISPLAY) {
+                MGLOG_E("wgl: no EGL display");
+                return nullptr;
+            }
+            EGLImpl::BindAPI(EGL_OPENGL_API);
+
+            EGLContext shareContext = EGL_NO_CONTEXT;
+            if (share) {
+                auto* shareObject = TryGetContext(share);
+                if (!shareObject) {
+                    SetLastError(ERROR_INVALID_HANDLE);
+                    return nullptr;
+                }
+                shareContext = shareObject->Context;
+            }
+
+            HWND hwnd = WindowFromDC(hdc);
+            const PixelFormatInfo& pixelFormat = PixelFormatForWindow(hwnd);
+            const EGLint configAttribs[] = {
+                EGL_RED_SIZE, 8,
+                EGL_GREEN_SIZE, 8,
+                EGL_BLUE_SIZE, 8,
+                EGL_ALPHA_SIZE, pixelFormat.AlphaBits,
+                EGL_DEPTH_SIZE, pixelFormat.DepthBits,
+                EGL_STENCIL_SIZE, pixelFormat.StencilBits,
+                EGL_SURFACE_TYPE, EGL_WINDOW_BIT | EGL_PBUFFER_BIT,
+                EGL_RENDERABLE_TYPE, EGL_OPENGL_BIT,
+                EGL_NONE,
+            };
+            EGLConfig config = nullptr;
+            EGLint configCount = 0;
+            if (!EGLImpl::ChooseConfig(display, configAttribs, &config, 1, &configCount) || configCount <= 0) {
+                MGLOG_E("wgl: eglChooseConfig failed");
+                return nullptr;
+            }
+
+            EGLContext eglContext = EGLImpl::CreateContext(display, config, shareContext, contextAttribs);
+            if (eglContext == EGL_NO_CONTEXT) {
+                MGLOG_E("wgl: eglCreateContext failed");
+                return nullptr;
+            }
+
+            ContextObject object;
+            object.Display = display;
+            object.Config = config;
+            object.Context = eglContext;
+            const auto handle = EncodeContext(NextContextHandle()++);
+            Contexts()[handle] = object;
+            MGLOG_I("wgl: created context %p (EGL context %p)", handle, eglContext);
+            return handle;
+        }
+
+        // ---- WGL extension entry points (resolved via wglGetProcAddress only) ----
+
+        const char* WINAPI Ext_GetExtensionsStringARB(HDC) {
+            return "WGL_ARB_create_context WGL_ARB_create_context_no_error WGL_ARB_create_context_profile "
+                   "WGL_ARB_extensions_string WGL_ARB_pixel_format WGL_EXT_extensions_string WGL_EXT_swap_control";
+        }
+
+        const char* WINAPI Ext_GetExtensionsStringEXT() {
+            return Ext_GetExtensionsStringARB(nullptr);
+        }
+
+        HGLRC WINAPI Ext_CreateContextAttribsARB(HDC hdc, HGLRC hShareContext, const int* attribList) {
+            EnsureInitialized();
+            int major = 1;
+            int minor = 0;
+            int profileMask = 0;
+            int flags = 0;
+            if (attribList) {
+                for (SizeT i = 0; attribList[i] != 0; i += 2) {
+                    const int attrib = attribList[i];
+                    const int value = attribList[i + 1];
+                    switch (attrib) {
+                    case WGL_CONTEXT_MAJOR_VERSION_ARB:
+                        major = value;
+                        break;
+                    case WGL_CONTEXT_MINOR_VERSION_ARB:
+                        minor = value;
+                        break;
+                    case WGL_CONTEXT_PROFILE_MASK_ARB:
+                        profileMask = value;
+                        break;
+                    case WGL_CONTEXT_FLAGS_ARB:
+                        flags = value;
+                        break;
+                    case WGL_CONTEXT_LAYER_PLANE_ARB:
+                        if (value != 0) {
+                            SetLastError(ERROR_INVALID_PARAMETER);
+                            return nullptr;
+                        }
+                        break;
+                    case WGL_CONTEXT_OPENGL_NO_ERROR_ARB:
+                        // Accepted and ignored: MobileGL always validates.
+                        break;
+                    default:
+                        MGLOG_D("wglCreateContextAttribsARB: ignoring attrib 0x%04x = 0x%x", attrib, value);
+                        break;
+                    }
+                }
+            }
+
+            if (major < 1 || (profileMask & ~(WGL_CONTEXT_CORE_PROFILE_BIT_ARB |
+                                              WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB))) {
+                SetLastError(profileMask ? ERROR_INVALID_PROFILE_ARB : ERROR_INVALID_VERSION_ARB);
+                return nullptr;
+            }
+
+            Vector<EGLint> attribs = {
+                EGL_CONTEXT_MAJOR_VERSION, major,
+                EGL_CONTEXT_MINOR_VERSION, minor,
+            };
+            const Bool wantsCompat = (profileMask & WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB) != 0;
+            if (major > 3 || (major == 3 && minor >= 2) || profileMask != 0) {
+                attribs.push_back(EGL_CONTEXT_OPENGL_PROFILE_MASK);
+                attribs.push_back(wantsCompat ? EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT
+                                              : EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT);
+            }
+            if (flags & WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB) {
+                attribs.push_back(EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE);
+                attribs.push_back(EGL_TRUE);
+            }
+            if (flags & WGL_CONTEXT_DEBUG_BIT_ARB) {
+                attribs.push_back(EGL_CONTEXT_OPENGL_DEBUG);
+                attribs.push_back(EGL_TRUE);
+            }
+            attribs.push_back(EGL_NONE);
+
+            return CreateContextFromEGLAttribs(hdc, hShareContext, attribs.data());
+        }
+
+        BOOL WINAPI Ext_SwapIntervalEXT(int interval) {
+            const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
+            EGLDisplay display = EnsureDisplay();
+            if (display == EGL_NO_DISPLAY) {
+                return FALSE;
+            }
+            if (interval < 0) {
+                // Adaptive vsync is not supported; clamp to regular vsync.
+                interval = 1;
+            }
+            EGLImpl::SwapInterval(display, interval);
+            SwapIntervalShadow() = interval;
+            return TRUE;
+        }
+
+        int WINAPI Ext_GetSwapIntervalEXT() {
+            const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
+            return SwapIntervalShadow();
+        }
+
+        int PixelFormatAttribValue(int format, int attrib) {
+            const PixelFormatInfo& info = kPixelFormats[format - 1];
+            switch (attrib) {
+            case WGL_NUMBER_PIXEL_FORMATS_ARB:
+                return kPixelFormatCount;
+            case WGL_SUPPORT_OPENGL_ARB:
+            case WGL_DRAW_TO_WINDOW_ARB:
+            case WGL_DOUBLE_BUFFER_ARB:
+                return 1;
+            case WGL_ACCELERATION_ARB:
+                return WGL_FULL_ACCELERATION_ARB;
+            case WGL_PIXEL_TYPE_ARB:
+                return WGL_TYPE_RGBA_ARB;
+            case WGL_COLOR_BITS_ARB:
+                return 32;
+            case WGL_RED_BITS_ARB:
+            case WGL_GREEN_BITS_ARB:
+            case WGL_BLUE_BITS_ARB:
+                return 8;
+            case WGL_RED_SHIFT_ARB:
+                return 16;
+            case WGL_GREEN_SHIFT_ARB:
+                return 8;
+            case WGL_BLUE_SHIFT_ARB:
+                return 0;
+            case WGL_ALPHA_BITS_ARB:
+                return info.AlphaBits;
+            case WGL_ALPHA_SHIFT_ARB:
+                return 24;
+            case WGL_DEPTH_BITS_ARB:
+                return info.DepthBits;
+            case WGL_STENCIL_BITS_ARB:
+                return info.StencilBits;
+            case WGL_SWAP_METHOD_ARB:
+                return WGL_SWAP_EXCHANGE_ARB;
+            case WGL_DRAW_TO_BITMAP_ARB:
+            case WGL_NEED_PALETTE_ARB:
+            case WGL_NEED_SYSTEM_PALETTE_ARB:
+            case WGL_SWAP_LAYER_BUFFERS_ARB:
+            case WGL_NUMBER_OVERLAYS_ARB:
+            case WGL_NUMBER_UNDERLAYS_ARB:
+            case WGL_TRANSPARENT_ARB:
+            case WGL_SHARE_DEPTH_ARB:
+            case WGL_SHARE_STENCIL_ARB:
+            case WGL_SHARE_ACCUM_ARB:
+            case WGL_SUPPORT_GDI_ARB:
+            case WGL_STEREO_ARB:
+            case WGL_ACCUM_BITS_ARB:
+            case WGL_ACCUM_RED_BITS_ARB:
+            case WGL_ACCUM_GREEN_BITS_ARB:
+            case WGL_ACCUM_BLUE_BITS_ARB:
+            case WGL_ACCUM_ALPHA_BITS_ARB:
+            case WGL_AUX_BUFFERS_ARB:
+            case WGL_SAMPLE_BUFFERS_ARB:
+            case WGL_SAMPLES_ARB:
+            default:
+                return 0;
+            }
+        }
+
+        BOOL WINAPI Ext_GetPixelFormatAttribivARB(HDC, int iPixelFormat, int iLayerPlane, UINT nAttributes,
+                                                  const int* piAttributes, int* piValues) {
+            if (iLayerPlane != 0 || !piAttributes || !piValues) {
+                return FALSE;
+            }
+            // Format 0 is only valid for WGL_NUMBER_PIXEL_FORMATS_ARB queries.
+            if (iPixelFormat < 0 || iPixelFormat > kPixelFormatCount) {
+                return FALSE;
+            }
+            const int format = iPixelFormat == 0 ? 1 : iPixelFormat;
+            for (UINT i = 0; i < nAttributes; ++i) {
+                piValues[i] = PixelFormatAttribValue(format, piAttributes[i]);
+            }
+            return TRUE;
+        }
+
+        BOOL WINAPI Ext_GetPixelFormatAttribfvARB(HDC hdc, int iPixelFormat, int iLayerPlane, UINT nAttributes,
+                                                  const int* piAttributes, FLOAT* pfValues) {
+            if (!pfValues) {
+                return FALSE;
+            }
+            Vector<int> values(nAttributes);
+            if (!Ext_GetPixelFormatAttribivARB(hdc, iPixelFormat, iLayerPlane, nAttributes, piAttributes,
+                                               values.data())) {
+                return FALSE;
+            }
+            for (UINT i = 0; i < nAttributes; ++i) {
+                pfValues[i] = static_cast<FLOAT>(values[i]);
+            }
+            return TRUE;
+        }
+
+        BOOL WINAPI Ext_ChoosePixelFormatARB(HDC, const int* piAttribIList, const FLOAT*, UINT nMaxFormats,
+                                             int* piFormats, UINT* nNumFormats) {
+            if (!piFormats || !nNumFormats) {
+                return FALSE;
+            }
+            int wantedStencil = 0;
+            if (piAttribIList) {
+                for (SizeT i = 0; piAttribIList[i] != 0; i += 2) {
+                    if (piAttribIList[i] == WGL_STENCIL_BITS_ARB) {
+                        wantedStencil = piAttribIList[i + 1];
+                    }
+                }
+            }
+            UINT count = 0;
+            const int preferred = wantedStencil > 0 ? 1 : 2;
+            const int fallback = wantedStencil > 0 ? 2 : 1;
+            if (count < nMaxFormats) {
+                piFormats[count++] = preferred;
+            }
+            if (count < nMaxFormats) {
+                piFormats[count++] = fallback;
+            }
+            *nNumFormats = count;
+            return TRUE;
+        }
+
+        struct WGLExtensionProc {
+            const char* Name;
+            PROC Proc;
+        };
+
+        const WGLExtensionProc kWGLExtensionProcs[] = {
+            {"wglGetExtensionsStringARB", reinterpret_cast<PROC>(Ext_GetExtensionsStringARB)},
+            {"wglGetExtensionsStringEXT", reinterpret_cast<PROC>(Ext_GetExtensionsStringEXT)},
+            {"wglCreateContextAttribsARB", reinterpret_cast<PROC>(Ext_CreateContextAttribsARB)},
+            {"wglSwapIntervalEXT", reinterpret_cast<PROC>(Ext_SwapIntervalEXT)},
+            {"wglGetSwapIntervalEXT", reinterpret_cast<PROC>(Ext_GetSwapIntervalEXT)},
+            {"wglGetPixelFormatAttribivARB", reinterpret_cast<PROC>(Ext_GetPixelFormatAttribivARB)},
+            {"wglGetPixelFormatAttribfvARB", reinterpret_cast<PROC>(Ext_GetPixelFormatAttribfvARB)},
+            {"wglChoosePixelFormatARB", reinterpret_cast<PROC>(Ext_ChoosePixelFormatARB)},
+        };
+    } // namespace
+
+    int ChoosePixelFormat(HDC hdc, const PIXELFORMATDESCRIPTOR* pfd) {
+        EnsureInitialized();
+        MGLOG_D("wglChoosePixelFormat(hdc=%p)", hdc);
+        // Format 1 (RGBA8 + depth24/stencil8) satisfies every request; a format
+        // exceeding the asked-for capabilities is a legal ChoosePixelFormat answer.
+        (void)pfd;
+        return 1;
+    }
+
+    int DescribePixelFormat(HDC hdc, int format, UINT size, PIXELFORMATDESCRIPTOR* pfd) {
+        EnsureInitialized();
+        MGLOG_D("wglDescribePixelFormat(hdc=%p, format=%d)", hdc, format);
+        if (!pfd) {
+            return kPixelFormatCount;
+        }
+        if (size < sizeof(PIXELFORMATDESCRIPTOR) || format < 1 || format > kPixelFormatCount) {
+            return 0;
+        }
+
+        const PixelFormatInfo& info = kPixelFormats[format - 1];
+        std::memset(pfd, 0, sizeof(PIXELFORMATDESCRIPTOR));
+        pfd->nSize = sizeof(PIXELFORMATDESCRIPTOR);
+        pfd->nVersion = 1;
+        pfd->dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER | PFD_SWAP_EXCHANGE
+#if defined(PFD_SUPPORT_COMPOSITION)
+                       | PFD_SUPPORT_COMPOSITION
+#endif
+            ;
+        pfd->iPixelType = PFD_TYPE_RGBA;
+        pfd->cColorBits = 32;
+        pfd->cRedBits = 8;
+        pfd->cRedShift = 16;
+        pfd->cGreenBits = 8;
+        pfd->cGreenShift = 8;
+        pfd->cBlueBits = 8;
+        pfd->cBlueShift = 0;
+        pfd->cAlphaBits = static_cast<BYTE>(info.AlphaBits);
+        pfd->cAlphaShift = 24;
+        pfd->cDepthBits = static_cast<BYTE>(info.DepthBits);
+        pfd->cStencilBits = static_cast<BYTE>(info.StencilBits);
+        pfd->iLayerType = PFD_MAIN_PLANE;
+        return kPixelFormatCount;
+    }
+
+    int GetPixelFormat(HDC hdc) {
+        EnsureInitialized();
+        HWND hwnd = WindowFromDC(hdc);
+        if (!hwnd) {
+            return 0;
+        }
+        const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
+        auto& formats = WindowPixelFormats();
+        auto it = formats.find(hwnd);
+        return it == formats.end() ? 0 : it->second;
+    }
+
+    BOOL SetPixelFormat(HDC hdc, int format, const PIXELFORMATDESCRIPTOR*) {
+        EnsureInitialized();
+        MGLOG_D("wglSetPixelFormat(hdc=%p, format=%d)", hdc, format);
+        if (format < 1 || format > kPixelFormatCount) {
+            SetLastError(ERROR_INVALID_PARAMETER);
+            return FALSE;
+        }
+        HWND hwnd = WindowFromDC(hdc);
+        if (!hwnd) {
+            SetLastError(ERROR_INVALID_HANDLE);
+            return FALSE;
+        }
+        const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
+        WindowPixelFormats()[hwnd] = format;
+        return TRUE;
+    }
+
+    BOOL SwapBuffers(HDC hdc) {
+        HWND hwnd = WindowFromDC(hdc);
+        if (!hwnd) {
+            SetLastError(ERROR_INVALID_HANDLE);
+            return FALSE;
+        }
+        const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
+        auto& surfaces = WindowSurfaces();
+        auto it = surfaces.find(hwnd);
+        if (it == surfaces.end()) {
+            MGLOG_W("wglSwapBuffers: no surface for HWND %p", hwnd);
+            return FALSE;
+        }
+        SyncSurfaceSize(hwnd, it->second);
+        return EGLImpl::SwapBuffers(it->second.Display, it->second.Surface) == EGL_TRUE ? TRUE : FALSE;
+    }
+
+    HGLRC CreateContext(HDC hdc) {
+        EnsureInitialized();
+        MGLOG_I("wglCreateContext(hdc=%p)", hdc);
+        // A legacy WGL context is a compatibility-profile context; MobileGL keys
+        // its relaxed-semantics mode off the explicit compatibility bit.
+        const EGLint attribs[] = {
+            EGL_CONTEXT_MAJOR_VERSION, 3,
+            EGL_CONTEXT_MINOR_VERSION, 3,
+            EGL_CONTEXT_OPENGL_PROFILE_MASK, EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT,
+            EGL_NONE,
+        };
+        return CreateContextFromEGLAttribs(hdc, nullptr, attribs);
+    }
+
+    BOOL DeleteContext(HGLRC hglrc) {
+        EnsureInitialized();
+        MGLOG_I("wglDeleteContext(%p)", hglrc);
+        if (t_current.Context == hglrc) {
+            MakeCurrent(nullptr, nullptr);
+        }
+        const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
+        auto* object = TryGetContext(hglrc);
+        if (!object) {
+            SetLastError(ERROR_INVALID_HANDLE);
+            return FALSE;
+        }
+        if (object->Context != EGL_NO_CONTEXT) {
+            EGLImpl::DestroyContext(object->Display, object->Context);
+        }
+        Contexts().erase(hglrc);
+        return TRUE;
+    }
+
+    BOOL MakeCurrent(HDC hdc, HGLRC hglrc) {
+        EnsureInitialized();
+        MGLOG_D("wglMakeCurrent(hdc=%p, hglrc=%p)", hdc, hglrc);
+        if (!hglrc) {
+            if (!t_current.Context) {
+                t_current = {};
+                return TRUE;
+            }
+            const EGLBoolean released =
+                EGLImpl::MakeCurrent(EGL_NO_DISPLAY, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+            t_current = {};
+            return released == EGL_TRUE ? TRUE : FALSE;
+        }
+
+        HWND hwnd = WindowFromDC(hdc);
+        if (!hwnd) {
+            SetLastError(ERROR_INVALID_HANDLE);
+            return FALSE;
+        }
+
+        const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
+        auto* object = TryGetContext(hglrc);
+        if (!object) {
+            SetLastError(ERROR_INVALID_HANDLE);
+            return FALSE;
+        }
+
+        WindowSurface* surface = EnsureWindowSurface(hwnd, *object);
+        if (!surface) {
+            return FALSE;
+        }
+
+        if (!EGLImpl::MakeCurrent(object->Display, surface->Surface, surface->Surface, object->Context)) {
+            MGLOG_E("wglMakeCurrent: eglMakeCurrent failed (hdc=%p, hglrc=%p)", hdc, hglrc);
+            return FALSE;
+        }
+        t_current = {hdc, hglrc};
+        return TRUE;
+    }
+
+    HGLRC GetCurrentContext() {
+        return t_current.Context;
+    }
+
+    HDC GetCurrentDC() {
+        return t_current.DC;
+    }
+
+    BOOL ShareLists(HGLRC hglrcShare, HGLRC hglrcDest) {
+        // All MobileGL contexts alias one global GL object namespace, so every
+        // pair of contexts already shares.
+        const std::lock_guard<std::recursive_mutex> lock(RegistryMutex());
+        if (!TryGetContext(hglrcShare) || !TryGetContext(hglrcDest)) {
+            SetLastError(ERROR_INVALID_HANDLE);
+            return FALSE;
+        }
+        return TRUE;
+    }
+
+    PROC GetProcAddress(const char* name) {
+        EnsureInitialized();
+        if (!name) {
+            return nullptr;
+        }
+        if (name[0] == 'w' && name[1] == 'g' && name[2] == 'l') {
+            for (const auto& entry : kWGLExtensionProcs) {
+                if (std::strcmp(entry.Name, name) == 0) {
+                    return entry.Proc;
+                }
+            }
+            MGLOG_D("wglGetProcAddress: unknown wgl entry point %s", name);
+            return nullptr;
+        }
+        return reinterpret_cast<PROC>(MG_Impl::GetProcAddress(name));
+    }
+} // namespace MobileGL::MG_Impl::WGLImpl
+
+#endif // _WIN32

MobileGL/MG_Impl/WGLImpl/WGLImpl.h

@@ -0,0 +1,34 @@
+// MobileGL - MobileGL/MG_Impl/WGLImpl/WGLImpl.h
+// 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
+
+#pragma once
+#include <Includes.h>
+
+#if defined(_WIN32)
+
+namespace MobileGL::MG_Impl::WGLImpl {
+    // Classic opengl32.dll surface. gdi32's ChoosePixelFormat/SetPixelFormat/
+    // DescribePixelFormat/GetPixelFormat/SwapBuffers forward into the loaded
+    // opengl32.dll's wgl* exports, so these back both call paths.
+    int ChoosePixelFormat(HDC hdc, const PIXELFORMATDESCRIPTOR* pfd);
+    int DescribePixelFormat(HDC hdc, int format, UINT size, PIXELFORMATDESCRIPTOR* pfd);
+    int GetPixelFormat(HDC hdc);
+    BOOL SetPixelFormat(HDC hdc, int format, const PIXELFORMATDESCRIPTOR* pfd);
+    BOOL SwapBuffers(HDC hdc);
+
+    HGLRC CreateContext(HDC hdc);
+    BOOL DeleteContext(HGLRC hglrc);
+    BOOL MakeCurrent(HDC hdc, HGLRC hglrc);
+    HGLRC GetCurrentContext();
+    HDC GetCurrentDC();
+    BOOL ShareLists(HGLRC hglrcShare, HGLRC hglrcDest);
+
+    PROC GetProcAddress(const char* name);
+} // namespace MobileGL::MG_Impl::WGLImpl
+
+#endif // _WIN32

MobileGL/MG_State/EGLState/Core.cpp

@@ -368,6 +368,26 @@ namespace MobileGL {
                 return true;
             }
 
+            Bool EGLContext::HasAnyInitializedDisplay() const {
+                const std::lock_guard<std::recursive_mutex> lock(m_mutex);
+                for (const auto& [handle, displayObject] : m_displays) {
+                    if (displayObject.Initialized) {
+                        return true;
+                    }
+                }
+                return false;
+            }
+
+            Bool EGLContext::HasAnyCurrentContext() const {
+                const std::lock_guard<std::recursive_mutex> lock(m_mutex);
+                for (const auto& [threadId, current] : m_threadCurrents) {
+                    if (current.Context != nullptr) {
+                        return true;
+                    }
+                }
+                return false;
+            }
+
             Bool EGLContext::ChooseConfig(EGLDisplayHandle display, const EGLint* attribList, EGLConfigHandle* configs,
                                           EGLint configSize, EGLint* numConfig) {
                 const std::lock_guard<std::recursive_mutex> lock(m_mutex);
@@ -764,6 +784,20 @@ namespace MobileGL {
                        ctx->MajorVersion > 3 || (ctx->MajorVersion == 3 && ctx->MinorVersion >= 1);
             }
 
+            Bool EGLContext::IsCurrentContextOpenGLCompatibilityProfile() const {
+                const std::lock_guard<std::recursive_mutex> lock(m_mutex);
+                auto currentIt = m_threadCurrents.find(CurrentThreadKey());
+                if (currentIt == m_threadCurrents.end()) {
+                    return false;
+                }
+                const auto* ctx = TryGetContext(currentIt->second.Context);
+                // Affirmative check: true only when the host explicitly requested the
+                // compatibility bit. Attrib-less contexts report false and thus read as core
+                // for GL_CONTEXT_PROFILE_MASK (EGL defaults 3.x contexts to the core profile).
+                return ctx && ctx->ClientAPI == EGL_OPENGL_API &&
+                       (ctx->OpenGLProfileMask & EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT);
+            }
+
             EGLint EGLContext::GetCurrentContextFlags() const {
                 const std::lock_guard<std::recursive_mutex> lock(m_mutex);
                 auto currentIt = m_threadCurrents.find(CurrentThreadKey());
@@ -1401,6 +1435,7 @@ namespace MobileGL {
             }
         } // namespace EGLState
 
-        UniquePtr<EGLState::EGLContext> pEGLContext;
+        // Leak-at-exit storage; see GlobalObjects.cpp.
+        UniquePtr<EGLState::EGLContext>& pEGLContext = *new UniquePtr<EGLState::EGLContext>();
     } // namespace MG_State
 } // namespace MobileGL

MobileGL/MG_State/EGLState/Core.h

@@ -39,6 +39,10 @@ namespace MobileGL {
                 Bool IsDisplayInitialized(EGLDisplayHandle display) const;
                 Bool InitializeDisplay(EGLDisplayHandle display, EGLint* major, EGLint* minor);
                 Bool TerminateDisplay(EGLDisplayHandle display);
+                // Whole-library idle checks used by EGLImpl::Terminate to decide
+                // when the last eglTerminate may tear MobileGL down entirely.
+                Bool HasAnyInitializedDisplay() const;
+                Bool HasAnyCurrentContext() const;
 
                 // Config
                 Bool ChooseConfig(EGLDisplayHandle display, const EGLint* attribList, EGLConfigHandle* configs,
@@ -59,6 +63,7 @@ namespace MobileGL {
                 Bool ValidateContext(EGLContextHandle context) const;
                 Bool ValidateContextOnDisplay(EGLDisplayHandle display, EGLContextHandle context) const;
                 Bool IsCurrentContextOpenGLCoreProfile() const;
+                Bool IsCurrentContextOpenGLCompatibilityProfile() const;
                 EGLint GetCurrentContextFlags() const;
 
                 // Surface
@@ -261,6 +266,6 @@ namespace MobileGL {
             };
         } // namespace EGLState
 
-        extern UniquePtr<EGLState::EGLContext> pEGLContext;
+        extern UniquePtr<EGLState::EGLContext>& pEGLContext;
     } // namespace MG_State
 } // namespace MobileGL

MobileGL/MG_State/GLState/Core.cpp

@@ -9,6 +9,7 @@
 #include "Core.h"
 #include "MG_State/GLState/RenderbufferState/RenderbufferObject.h"
 #include "MG_State/EGLState/Core.h"
+#include <Config.h>
 
 namespace MobileGL::MG_State {
     void Init() {
@@ -17,6 +18,11 @@ namespace MobileGL::MG_State {
         pEGLContext = MakeUnique<EGLState::EGLContext>();
     }
 
+    Bool IsRelaxedSemanticsActive() {
+        return MG_Config::Features.RelaxedSemantics ||
+               !(pEGLContext && pEGLContext->IsCurrentContextOpenGLCoreProfile());
+    }
+
     namespace GLState {
         // Error
         void GLContext::RecordError(ErrorCode code, UniquePtr<ErrorInfo> info) {
@@ -226,12 +232,16 @@ namespace MobileGL::MG_State {
             return m_textureState.GetTextureObject(index);
         }
 
+        const SharedPtr<ITextureObject>& GLContext::GetDefaultTextureObject(TextureTarget target) const {
+            return m_textureState.GetDefaultTextureObject(target);
+        }
+
         const SharedPtr<ITextureObject>& GLContext::CreateTextureObject(Uint index, TextureTarget target) {
             return m_textureState.CreateTextureObject(index, target);
         }
 
         void GLContext::MarkTextureObjectForDeletion(Uint index) {
-            m_textureState.MarkTextureObjectForDeletion(index);
+            m_textureState.MarkTextureObjectForDeletion(index, IsRelaxedSemanticsActive());
         }
 
         TextureUnit& GLContext::GetTextureUnitObject(Int unit) {
@@ -279,6 +289,10 @@ namespace MobileGL::MG_State {
             return m_programState.MarkShaderObjectForDeletion(index);
         }
 
+        void GLContext::ReleaseShaderNameIfOrphaned(const Uint index) {
+            return m_programState.ReleaseShaderNameIfOrphaned(index);
+        }
+
         Bool GLContext::ValidateProgramName(const Uint index) const {
             return m_programState.ValidateProgramObject(index);
         }
@@ -707,5 +721,6 @@ namespace MobileGL::MG_State {
         }
     } // namespace GLState
 
-    UniquePtr<GLState::GLContext> pGLContext;
+    // Leak-at-exit storage; see GlobalObjects.cpp.
+    UniquePtr<GLState::GLContext>& pGLContext = *new UniquePtr<GLState::GLContext>();
 } // namespace MobileGL::MG_State

MobileGL/MG_State/GLState/Core.h

@@ -95,6 +95,8 @@ namespace MobileGL {
                 // Texture
                 void GenTextureNames(Uint number, Vector<Uint>& textures);
                 const SharedPtr<ITextureObject>& GetTextureObject(Uint index);
+                // Per-target default texture object (name 0); see TextureState::GetDefaultTextureObject.
+                const SharedPtr<ITextureObject>& GetDefaultTextureObject(TextureTarget target) const;
                 const SharedPtr<ITextureObject>& CreateTextureObject(Uint index, TextureTarget target);
                 void MarkTextureObjectForDeletion(Uint index);
                 TextureUnit& GetTextureUnitObject(Int unit);
@@ -106,6 +108,7 @@ namespace MobileGL {
                 // texture is bound at a unit; lets a backend skip re-resolving an unchanged
                 // per-draw sampled-texture set.
                 Uint64 GetTextureBindGeneration() const { return m_textureState.GetTextureBindGeneration(); }
+                void BumpTextureBindGeneration() { m_textureState.BumpTextureBindGeneration(); }
                 Bool ValidateTextureName(Uint index) const;
                 Bool ValidateTextureObject(Uint index) const;
                 Int GetActiveTextureUnit() const;
@@ -116,6 +119,9 @@ namespace MobileGL {
                 Uint CreateShader(ShaderStage stage);
                 void MarkProgramForDeletion(Uint index);
                 void MarkShaderForDeletion(Uint index);
+                // Frees a deletion-flagged shader's name once it lost its last GL-visible
+                // attachment (call after glDetachShader).
+                void ReleaseShaderNameIfOrphaned(Uint index);
                 Bool ValidateProgramName(Uint index) const;
                 Bool ValidateShaderName(Uint index) const;
                 const SharedPtr<ProgramObject>& GetProgramObject(Uint index);
@@ -246,6 +252,13 @@ namespace MobileGL {
             };
         } // namespace GLState
 
-        extern UniquePtr<GLState::GLContext> pGLContext;
+        extern UniquePtr<GLState::GLContext>& pGLContext;
+
+        // True when relaxed GL semantics apply. Strict core rules are enforced only when the
+        // current EGL context explicitly requested a core profile (core bit in
+        // EGL_CONTEXT_OPENGL_PROFILE_MASK, or a >=3.1 version request without the compatibility
+        // bit) and MOBILEGL_RELAXED_SEMANTICS is off; no current context, legacy version
+        // requests, and the compatibility bit all relax.
+        Bool IsRelaxedSemanticsActive();
     } // namespace MG_State
 } // namespace MobileGL

MobileGL/MG_State/GLState/ErrorState/Error.cpp

@@ -7,6 +7,7 @@
 // End of Source File Header
 
 #include "Error.h"
+#include <algorithm>
 #include <MG_Util/Converters/GLToStr/GLEnumConverter.h>
 #include <MG_Util/Converters/MGToGL/ErrorCodeConverter.h>
 
@@ -19,7 +20,15 @@ namespace MobileGL::MG_State::GLState {
             MGLOG_E("Recording OpenGL error (%s):\n%s",
                     MG_Util::ConvertGLEnumToString(MG_Util::ConvertErrorCodeToGLEnum(code)).c_str(),
                     info->toString().c_str());
-            m_errors.push_back(MakeUnique<Error>(code, Move(info)));
+            // GL error semantics are sticky flags, not a queue (GL 3.3 core §2.5): with multiple
+            // error flags, each is set only while currently unset — repeated errors of the same
+            // code are discarded until glGetError reads the flag. Unbounded accumulation leaked
+            // stale errors into later, unrelated glGetError checks (GL CTS deinit noise).
+            const Bool alreadyPending = std::any_of(m_errors.begin(), m_errors.end(),
+                                                    [code](const auto& e) { return e->code == code; });
+            if (!alreadyPending) {
+                m_errors.push_back(MakeUnique<Error>(code, Move(info)));
+            }
         }
     }
 

MobileGL/MG_State/GLState/ProgramState/ProgramObject.cpp

@@ -8,6 +8,7 @@
 
 #include "ProgramObject.h"
 #include <atomic>
+#include <cstring>
 #include <MG_Backend/BackendObjects.h>
 #include <MG_State/GLState/VertexArrayState/VertexArrayObject.h>
 #include <MG_Util/Converters/GLToStr/GLEnumConverter.h>
@@ -87,6 +88,19 @@ namespace {
         }
     }
 
+    // How many consecutive uniform locations a uniform occupies. Array uniforms (opaque
+    // or not) span one location per element so glUniform*v(count > 1) and
+    // glGetUniformLocation("arr[k]") can address elements individually; everything else
+    // spans a single location. TObjectReflection.size only carries the element count for
+    // non-block arrays, so prefer the TType, which is authoritative for both.
+    static MobileGL::Int GetUniformLocationSpan(const glslang::TObjectReflection& uniform) {
+        const glslang::TType* type = uniform.getType();
+        if (type != nullptr && type->isSizedArray()) {
+            return std::max(1, type->getOuterArraySize());
+        }
+        return std::max(1, uniform.size);
+    }
+
     static bool ComputeShaderDeclaresLocalSize(const MobileGL::String& source) {
         bool inLineComment = false;
         bool inBlockComment = false;
@@ -346,7 +360,18 @@ namespace MobileGL::MG_State::GLState {
         }
 
         MGLOG_D("ProgramObject %u: DoReflection - building reflection", m_externalIndex);
-        if (!m_program->buildReflection()) {
+        // GL-style reflection naming (GL CTS uniform_block relies on all four):
+        //  - BasicArraySuffix: an array uniform is reported as "arr[0]" per the GL spec.
+        //  - StrictArraySuffix: named-block struct arrays expand per element ("s[0].a",
+        //    "s[1].a", ...) following ARB_program_interface_query rules. Default-block
+        //    (loose) uniforms already expand per element without this option.
+        //  - AllBlockVariables: every member of an active named block is active even when
+        //    no shader statement reads it (ES 3.0/GL 3.3 named-block semantics).
+        //  - SharedStd140UBO: a DECLARED uniform block is active even when no member is
+        //    ever read (reflected from the linker objects). PreprocessShaderSource coerces
+        //    every block to std140, so this covers all of them.
+        if (!m_program->buildReflection(EShReflectionStrictArraySuffix | EShReflectionBasicArraySuffix |
+                                        EShReflectionAllBlockVariables | EShReflectionSharedStd140UBO)) {
             m_linkStatus = false;
             m_infoLog = "Build reflection failed.";
             MGLOG_E("ProgramObject %u: DoReflection - buildReflection() returned false", m_externalIndex);
@@ -361,8 +386,7 @@ namespace MobileGL::MG_State::GLState {
         for (int i = 0; i < m_activeUniformCount; i++) {
             auto& uniform = m_program->getUniform(i);
             auto location = uniform.layoutLocation();
-            const Int locationSpan =
-                (uniform.getType() && uniform.getType()->isOpaque()) ? std::max(1, uniform.size) : 1;
+            const Int locationSpan = GetUniformLocationSpan(uniform);
             requiredUniformLocations += locationSpan;
             if (location != glslang::TQualifier::layoutLocationEnd) {
                 m_maxUniformLocation = std::max(m_maxUniformLocation, location + locationSpan - 1);
@@ -401,8 +425,7 @@ namespace MobileGL::MG_State::GLState {
                         m_externalIndex, uniform.name.c_str());
                 continue; // will allocate unallocated uniforms later
             }
-            const Int locationSpan =
-                (uniform.getType() && uniform.getType()->isOpaque()) ? std::max(1, uniform.size) : 1;
+            const Int locationSpan = GetUniformLocationSpan(uniform);
             for (Int element = 0; element < locationSpan; ++element) {
                 m_uniformIndexInTProgram[location + element] = i;
             }
@@ -419,8 +442,8 @@ namespace MobileGL::MG_State::GLState {
         });
         for (auto index : unallocatedUniformIndex) {
             auto& uniform = m_program->getUniform(index);
-            const Int locationSpan =
-                (uniform.getType() && uniform.getType()->isOpaque()) ? std::max(1, uniform.size) : 1;
+            const Int locationSpan = GetUniformLocationSpan(uniform);
+            Bool placed = false;
             for (; locNeedle <= m_maxUniformLocation; locNeedle++) {
                 bool hasRoom = locNeedle + locationSpan - 1 <= m_maxUniformLocation;
                 for (Int element = 0; hasRoom && element < locationSpan; ++element) {
@@ -437,8 +460,25 @@ namespace MobileGL::MG_State::GLState {
                         "(index %d)",
                         m_externalIndex, uniform.name.c_str(), locNeedle, locNeedle + locationSpan - 1, index);
                 locNeedle += locationSpan;
+                placed = true;
                 break;
             }
+            if (!placed) {
+                // Explicit-location uniforms can fragment the space so no contiguous
+                // span is left; grow the table instead of leaving the uniform without
+                // a location (which would make it unsettable via glUniform*).
+                const SizeT base = m_uniformIndexInTProgram.size();
+                m_uniformIndexInTProgram.resize(base + locationSpan, glslang::TQualifier::layoutLocationEnd);
+                m_uniformSamplerOrImageUnitIndex.resize(base + locationSpan, -1);
+                m_maxUniformLocation = static_cast<Uint>(base + locationSpan - 1);
+                for (Int element = 0; element < locationSpan; ++element) {
+                    m_uniformIndexInTProgram[base + element] = index;
+                }
+                m_uniformLocations[uniform.name] = static_cast<Uint>(base);
+                MGLOG_D("ProgramObject %u: Reflection - grew location table to place uniform '%s' at %zu..%zu",
+                        m_externalIndex, uniform.name.c_str(), base, base + locationSpan - 1);
+                locNeedle = base + locationSpan;
+            }
         }
 
         for (int i = 0; i < m_activeUniformCount; i++) {
@@ -454,10 +494,17 @@ namespace MobileGL::MG_State::GLState {
                 continue;
             }
 
-            const auto explicitBinding = m_explicitOpaqueUniformBindings.find(uniform.name);
+            // Reflection names an array "texs[0]" while the layout(binding = N) map from the IO
+            // resolver is keyed by the declared name ("texs"); look up both spellings.
+            auto explicitBinding = m_explicitOpaqueUniformBindings.find(uniform.name);
+            if (explicitBinding == m_explicitOpaqueUniformBindings.end() && uniform.name.length() > 3 &&
+                uniform.name.compare(uniform.name.length() - 3, 3, "[0]") == 0) {
+                explicitBinding =
+                    m_explicitOpaqueUniformBindings.find(uniform.name.substr(0, uniform.name.length() - 3));
+            }
             const int initialUnit =
                 explicitBinding != m_explicitOpaqueUniformBindings.end() ? static_cast<int>(explicitBinding->second) : 0;
-            const Int locationSpan = std::max(1, uniform.size);
+            const Int locationSpan = GetUniformLocationSpan(uniform);
             for (Int element = 0; element < locationSpan &&
                                   location + element < m_uniformSamplerOrImageUnitIndex.size(); ++element) {
                 m_uniformSamplerOrImageUnitIndex[location + element] =
@@ -622,8 +669,11 @@ namespace MobileGL::MG_State::GLState {
         m_uniformSizesInBytes.clear();
         m_uniformOffsets.clear();
         m_globalUboScratch.clear();
-        m_uniformOffsets.resize(m_maxUniformLocation + 1);
-        m_uniformSizesInBytes.resize(m_maxUniformLocation + 1);
+        // kInvalidUniformOffset marks locations that end up without global-UBO backing
+        // (e.g. the optimizer eliminated every use of the uniform); the fallback pass
+        // below gives those locations tail storage so glUniform* always has a target.
+        m_uniformOffsets.resize(m_maxUniformLocation + 1, kInvalidUniformOffset);
+        m_uniformSizesInBytes.resize(m_maxUniformLocation + 1, 0);
         for (SizeT i = 0; i < m_generatedSpirv.size(); i++) {
             auto& spv = m_generatedSpirv[i];
 
@@ -653,31 +703,95 @@ namespace MobileGL::MG_State::GLState {
                     m_globalUboScratch.resize(size);
                 }
                 for (const auto& [name, offset] : meta.plainUniformOffsetsInUBO) {
-                    if (m_uniformLocations.find(name) != m_uniformLocations.end()) {
-                        m_uniformOffsets[m_uniformLocations[name]] = offset;
-                        MGLOG_D("ProgramObject %u: GenerateBinary - uniform '%s' offset=%u assigned to location %u",
-                                m_externalIndex, name.c_str(), offset, m_uniformLocations[name]);
-            } else {
-                MGLOG_D("ProgramObject %u: GenerateBinary - uniform '%s' offset=%u but not found in "
-                        "m_uniformLocations",
-                        m_externalIndex, name.c_str(), offset);
-            }
-                }
-                for (const auto& [name, size] : meta.plainUniformMemberSizesInBytes) {
-                    if (m_uniformLocations.find(name) != m_uniformLocations.end()) {
-                        m_uniformSizesInBytes[m_uniformLocations[name]] = size;
-                        MGLOG_D("ProgramObject %u: GenerateBinary - uniform '%s' size=%u assigned to location %u",
-                                m_externalIndex, name.c_str(), size, m_uniformLocations[name]);
-            } else {
-                MGLOG_D("ProgramObject %u: GenerateBinary - uniform '%s' size=%u but not found in "
-                        "m_uniformLocations",
-                        m_externalIndex, name.c_str(), size);
-            }
+                    // SPIRV-Reflect leaf names never carry a "[0]" suffix; frontend
+                    // reflection keys arrays as "arr[0]" (GL naming), so retry with the
+                    // suffix before declaring the uniform unbacked.
+                    auto locationIt = m_uniformLocations.find(name);
+                    if (locationIt == m_uniformLocations.end()) {
+                        locationIt = m_uniformLocations.find(name + "[0]");
+                    }
+                    if (locationIt == m_uniformLocations.end()) {
+                        MGLOG_D("ProgramObject %u: GenerateBinary - uniform '%s' offset=%u but not found in "
+                                "m_uniformLocations",
+                                m_externalIndex, name.c_str(), offset);
+                        continue;
+                    }
+                    const Uint baseLocation = locationIt->second;
+                    if (!IsValidUniformLocation(static_cast<Int>(baseLocation))) {
+                        continue;
+                    }
+
+                    const Int uniformIndex = m_uniformIndexInTProgram[baseLocation];
+                    const GLint arraySize = GetActiveUniformArraySize(uniformIndex);
+                    SizeT memberSize = 0;
+                    const auto sizeIt = meta.plainUniformMemberSizesInBytes.find(name);
+                    if (sizeIt != meta.plainUniformMemberSizesInBytes.end()) {
+                        memberSize = sizeIt->second;
+                    }
+                    Uint arrayStride = 0;
+                    const auto strideIt = meta.plainUniformArrayStridesInUBO.find(name);
+                    if (strideIt != meta.plainUniformArrayStridesInUBO.end()) {
+                        arrayStride = strideIt->second;
+                    }
+
+                    // Array uniforms span one location per element (see DoReflection);
+                    // give each element its real byte offset inside the UBO.
+                    const GLint elementCount = (arraySize > 1 && arrayStride == 0) ? 1 : std::max(arraySize, 1);
+                    for (GLint element = 0; element < elementCount; ++element) {
+                        const Uint location = baseLocation + static_cast<Uint>(element);
+                        if (location > m_maxUniformLocation || m_uniformIndexInTProgram[location] != uniformIndex) {
+                            break;
+                        }
+                        m_uniformOffsets[location] = offset + static_cast<Uint>(element) * arrayStride;
+                        const SizeT consumed = static_cast<SizeT>(element) * arrayStride;
+                        m_uniformSizesInBytes[location] = memberSize > consumed ? memberSize - consumed : 0;
+                    }
+                    MGLOG_D("ProgramObject %u: GenerateBinary - uniform '%s' offset=%u stride=%u size=%zu assigned "
+                            "to locations %u..%u",
+                            m_externalIndex, name.c_str(), offset, arrayStride, memberSize, baseLocation,
+                            baseLocation + static_cast<Uint>(elementCount) - 1);
                 }
                 MGLOG_D("ProgramObject %u: GenerateBinary - finished parsing module %zu metadata",
                         m_externalIndex, i);
             }
         }
+
+        // Fallback pass: a linked program's active non-opaque uniforms must accept
+        // glUniform*/glGetUniform* even when the optimized SPIR-V no longer contains
+        // them (AggressiveDCE can remove a dead loop together with the only loads of a
+        // uniform -- or the entire global UBO, leaving the scratch unallocated). Hand
+        // such locations CPU-side storage at the (16-byte aligned) tail of the shadow
+        // buffer; backends bind at least the SPIR-V-declared UBO range, and the GPU
+        // never reads these bytes, so this only keeps the GL-visible state coherent.
+        for (Uint location = 0; location <= m_maxUniformLocation; ++location) {
+            if (m_uniformOffsets[location] != kInvalidUniformOffset) continue;
+            if (!IsValidUniformLocation(static_cast<Int>(location))) continue;
+            const auto& uniform = m_program->getUniform(m_uniformIndexInTProgram[location]);
+            const glslang::TType* type = uniform.getType();
+            if (type != nullptr && type->isOpaque()) continue;
+            if (uniform.index >= 0 && uniform.index < m_program->getNumUniformBlocks() &&
+                std::strstr(m_program->getUniformBlock(uniform.index).name.c_str(),
+                            MG_Util::ShaderTranspiler::GLOBAL_UBO_NAME) == nullptr) {
+                // Member of a named uniform block: not settable through glUniform*, so it
+                // needs no global-UBO shadow storage.
+                continue;
+            }
+
+            // std140-style slot: the matrix upload paths write column vectors at
+            // 16-byte strides, so a matrix slot must cover cols * 16 bytes.
+            SizeT slotSize = MG_Util::GetGLTypeSize(uniform.glDefineType);
+            if (type != nullptr && type->isMatrix()) {
+                slotSize = static_cast<SizeT>(type->getMatrixCols()) * 16u;
+            }
+            slotSize = (slotSize + 15u) & ~static_cast<SizeT>(15u);
+            const SizeT slotOffset = (m_globalUboScratch.size() + 15u) & ~static_cast<SizeT>(15u);
+            m_globalUboScratch.resize(slotOffset + slotSize, 0);
+            m_uniformOffsets[location] = static_cast<Uint>(slotOffset);
+            m_uniformSizesInBytes[location] = slotSize;
+            MGLOG_D("ProgramObject %u: GenerateBinary - uniform '%s' location %u has no UBO backing in the "
+                    "generated SPIR-V (optimized out?); allocated %zu fallback bytes at scratch offset %zu",
+                    m_externalIndex, uniform.name.c_str(), location, slotSize, slotOffset);
+        }
     }
 
     void ProgramObject::WaitUntilGenerationCompleted() const {

MobileGL/MG_State/GLState/ProgramState/ProgramObject.h

@@ -18,6 +18,13 @@ namespace MobileGL::MG_State::GLState {
     public:
         ProgramObject(Uint externalIndex) : m_externalIndex(externalIndex), m_lifetimeId(AllocateLifetimeId()) {}
         bool ShaderIsAttached(const SharedPtr<ShaderObject>& shader);
+        // GL-visible attachment: in the attach list and not pending detach (glDetachShader
+        // defers the actual removal to the next link).
+        Bool ShaderIsAttachedGLVisible(const SharedPtr<ShaderObject>& shader) const {
+            const auto matches = [&shader](const SharedPtr<ShaderObject>& s) { return s.get() == shader.get(); };
+            if (std::none_of(m_shaders.begin(), m_shaders.end(), matches)) return false;
+            return std::none_of(m_detachedShaders.begin(), m_detachedShaders.end(), matches);
+        }
         bool AttachShader(const SharedPtr<ShaderObject>& shader);
         SizeT DetachShader(const SharedPtr<ShaderObject>& shader);
         SizeT RemoveShader(const SharedPtr<ShaderObject>& shader);
@@ -43,8 +50,51 @@ namespace MobileGL::MG_State::GLState {
         Uint GetMaxUniformLocation() const { return m_maxUniformLocation; }
         Int GetUniformLocation(const String& name) const {
             const auto it = m_uniformLocations.find(name);
-            if (it == m_uniformLocations.end()) return -1;
-            return (Int)it->second;
+            if (it != m_uniformLocations.end()) return (Int)it->second;
+
+            // Reflection stores GL-style names: an array uniform is keyed "arr[0]" (its base
+            // location). A bare "arr" query resolves to that entry; an "arr[k]" query resolves
+            // to base + k because DoReflection reserves one location per array element.
+            if (name.empty()) return -1;
+            if (name.back() != ']') {
+                const auto suffixedIt = m_uniformLocations.find(name + "[0]");
+                if (suffixedIt != m_uniformLocations.end()) return (Int)suffixedIt->second;
+                return -1;
+            }
+            if (name.length() < 4) return -1;
+            const SizeT bracket = name.rfind('[');
+            // Require at least one digit between the brackets.
+            if (bracket == String::npos || bracket + 1 >= name.length() - 1) return -1;
+            Uint element = 0;
+            for (SizeT i = bracket + 1; i < name.length() - 1; ++i) {
+                if (name[i] < '0' || name[i] > '9') return -1;
+                element = element * 10 + static_cast<Uint>(name[i] - '0');
+                if (element > 0x0FFFFFFFu) return -1;
+            }
+            auto baseIt = m_uniformLocations.find(name.substr(0, bracket) + "[0]");
+            if (baseIt == m_uniformLocations.end()) {
+                // Legacy key without the "[0]" suffix (defensive; reflection normally
+                // stores the suffixed form for arrays).
+                baseIt = m_uniformLocations.find(name.substr(0, bracket));
+                if (baseIt == m_uniformLocations.end()) return -1;
+            }
+            const Int base = (Int)baseIt->second;
+            if (!IsValidUniformLocation(base)) return -1;
+            const Int index = m_uniformIndexInTProgram[base];
+            // "[k]" only addresses arrays ("scalar[0]" is not a uniform name), and only
+            // in-range elements.
+            const glslang::TType* type = m_program->getUniform(index).getType();
+            if (type == nullptr || !type->isArray()) return -1;
+            if (static_cast<GLint>(element) >= GetActiveUniformArraySize(index)) return -1;
+            const Int location = base + (Int)element;
+            if (!UniformLocationsAliasSameUniform(base, location)) return -1;
+            return location;
+        }
+
+        // True when both locations are element slots of the same uniform variable.
+        Bool UniformLocationsAliasSameUniform(Int a, Int b) const {
+            if (!IsValidUniformLocation(a) || !IsValidUniformLocation(b)) return false;
+            return m_uniformIndexInTProgram[a] == m_uniformIndexInTProgram[b];
         }
 
         Int GetActiveUniformIndex(const String& name) const {
@@ -54,6 +104,19 @@ namespace MobileGL::MG_State::GLState {
                 return uniformIndex;
             }
 
+            // Reflection stores an array uniform under "arr[0]"; accept the bare "arr"
+            // spelling too. The reverse ("arr[0]" against a bare "arr" entry) is kept for
+            // robustness against non-suffixed reflection entries.
+            if (!name.empty() && name.back() != ']') {
+                const String suffixedName = name + "[0]";
+                const Int suffixedIndex = m_program->getUniformIndex(suffixedName.c_str());
+                if (suffixedIndex >= 0 && suffixedIndex < m_activeUniformCount &&
+                    m_program->getUniform(suffixedIndex).name == suffixedName) {
+                    return suffixedIndex;
+                }
+                return -1;
+            }
+
             if (name.length() <= 3 || name.compare(name.length() - 3, 3, "[0]") != 0) return -1;
             const String baseName = name.substr(0, name.length() - 3);
             const Int baseIndex = m_program->getUniformIndex(baseName.c_str());
@@ -104,11 +167,24 @@ namespace MobileGL::MG_State::GLState {
         }
 
         // GL_UNIFORM_ARRAY_STRIDE: byte stride of an array member in a named block; 0 for a non-array
-        // block member; -1 for a default-block uniform. glslang yields arrayStride==0 for the
-        // default-block case, so gate on block membership to return the spec-mandated -1.
+        // block member; -1 for a default-block uniform (glslang yields arrayStride==0 there, so gate
+        // on block membership for the spec-mandated -1). The stride itself is derived from the type
+        // instead of glslang's reflected arrayStride: for an array nested inside a struct member,
+        // glslang computes that field against the enclosing STRUCT's (unset) packing and reports a
+        // tight std430-like stride (ivec2 a[7] -> 8), even though its own member offsets and the
+        // generated SPIR-V lay the array out with std140 16-byte-rounded strides. MobileGL's UBO
+        // layout is always std140, where every array element stride rounds up to a vec4.
         GLint GetActiveUniformArrayStride(Uint index) const {
             const auto& uniform = m_program->getUniform(static_cast<Int>(index));
-            return (uniform.index < 0) ? -1 : uniform.arrayStride;
+            if (uniform.index < 0) return -1;
+            const glslang::TType* type = uniform.getType();
+            if (type == nullptr || !type->isArray()) return 0;
+            if (type->isMatrix()) {
+                const bool rowMajor = GetActiveUniformIsRowMajor(index) != 0;
+                const int vectors = rowMajor ? type->getMatrixRows() : type->getMatrixCols();
+                return GetActiveUniformMatrixStride(index) * vectors;
+            }
+            return 16; // scalars and vectors: std140 rounds the element stride up to a vec4
         }
 
         // GL_UNIFORM_IS_ROW_MAJOR: 1 only for a row-major matrix in a named block, else 0. The
@@ -170,6 +246,9 @@ namespace MobileGL::MG_State::GLState {
             auto& uniform = m_program->getUniform(static_cast<Int>(index));
             return uniform.name;
         }
+        // Sentinel for a uniform location without global-UBO backing storage (should not
+        // survive linking: GenerateBinary falls back to tail-allocated scratch storage).
+        static constexpr Uint kInvalidUniformOffset = ~0u;
         Uint GetUniformOffset(Uint location) const { return m_uniformOffsets[location]; }
         Uint GetUniformSizesInBytes(Uint location) const { return MG_Util::GetGLTypeSize(GetUniformType(location)); }
 
@@ -292,6 +371,11 @@ namespace MobileGL::MG_State::GLState {
         Uint GetUniformBlockIndex(const char* name) const {
             auto it = m_uniformBlockIndexByName.find(name);
             if (it != m_uniformBlockIndexByName.end()) return it->second;
+            // Instances of an arrayed block are reflected as "Block[0]".."Block[N-1]";
+            // a bare "Block" query resolves to the first instance per GL semantics.
+            const String suffixedName = String(name) + "[0]";
+            it = m_uniformBlockIndexByName.find(suffixedName);
+            if (it != m_uniformBlockIndexByName.end()) return it->second;
             return 0xFFFFFFFFu; // GL_INVALID_INDEX
         }
         Bool IsActiveUniformBlock(Uint index) const {
@@ -300,7 +384,11 @@ namespace MobileGL::MG_State::GLState {
         }
         Uint GetUBOSizeAt(Uint index) const {
             if (!IsActiveUniformBlock(index)) return 0;
-            return m_program->getUniformBlock((Int)index).size;
+            // glslang reports the unpadded end offset of the last member, but a std140 block
+            // (like a std140 struct) occupies a vec4-rounded size, and that is what the
+            // backend compiles: ES drivers reject draws whose bound UBO range is smaller
+            // than the block (a block ending in ivec3 reported 12 while the driver needs 16).
+            return (m_program->getUniformBlock((Int)index).size + 15u) & ~15u;
         }
 
         const String& GetUniformBlockName(Uint index) const {
@@ -308,8 +396,30 @@ namespace MobileGL::MG_State::GLState {
             return ubo.name;
         }
 
+        // Uniform entries that belong to an arrayed uniform block are reflected once, against
+        // the first instance ("Block[0]"); per GL semantics every other instance shares that
+        // member set. Maps any instance's block index to the index owning the member entries.
+        Uint GetUniformBlockMemberOwnerIndex(Uint index) const {
+            const String& name = GetUniformBlockName(index);
+            if (name.empty() || name.back() != ']') return index;
+            const SizeT bracket = name.rfind('[');
+            if (bracket == String::npos) return index;
+            const auto it = m_uniformBlockIndexByName.find(name.substr(0, bracket) + "[0]");
+            if (it != m_uniformBlockIndexByName.end()) return it->second;
+            return index;
+        }
+
+        // GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS: derived from the same active-uniform scan that
+        // fills GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES, so the two queries always agree
+        // (glslang's numMembers counts declared members, which diverges from the reflected
+        // entry list for struct arrays and arrayed block instances).
         Int GetUniformBlockActiveUniformCount(Uint index) const {
-            return m_program->getUniformBlock((Int)index).numMembers;
+            const Int ownerIndex = static_cast<Int>(GetUniformBlockMemberOwnerIndex(index));
+            Int count = 0;
+            for (Uint uniformIndex = 0; uniformIndex < m_activeUniformCount; ++uniformIndex) {
+                if (GetActiveUniformBlockIndex(uniformIndex) == ownerIndex) ++count;
+            }
+            return count;
         }
 
         Bool IsUniformBlockReferencedByStage(Uint index, EShLanguage stage) const {

MobileGL/MG_State/GLState/ProgramState/ProgramState.cpp

@@ -29,9 +29,18 @@ namespace MobileGL::MG_State::GLState {
         if (!CheckIndexAvail(program, m_programObjects)) return; // FIXME: add error reporting here
         auto& programObject = m_programObjects[program];
         if (programObject != nullptr) {
+            // Snapshot the attachments: deleting the program is a detach point for shaders
+            // that were flagged with glDeleteShader while still attached.
+            const Vector<SharedPtr<ShaderObject>> attachedShaders = programObject->GetAttachedShaders();
             programObject->MarkAsDeleted();
             programObject.reset();
             m_programIndexGenerator.Delete(program);
+            for (const auto& shader : attachedShaders) {
+                const Uint shaderName = shader->GetExternalIndex();
+                if (CheckIndexAvail(shaderName, m_shaderObjects) && m_shaderObjects[shaderName] == shader) {
+                    ReleaseShaderNameIfOrphaned(shaderName);
+                }
+            }
         }
     }
 
@@ -66,12 +75,35 @@ namespace MobileGL::MG_State::GLState {
         if (!CheckIndexAvail(shader, m_shaderObjects)) return;
         auto& shaderObject = m_shaderObjects[shader];
         if (shaderObject != nullptr) {
-            m_shaderObjects[shader]->MarkAsDeleted();
-            m_shaderObjects[shader].reset();
-            m_shaderIndexGenerator.Delete(shader);
+            // glDeleteShader on an attached shader only FLAGS it; the name stays valid (and
+            // glShaderSource/glCompileShader keep working on it) until the shader is detached
+            // from every program. The GL CTS compiles shaders through exactly this
+            // create-attach-delete-source-compile sequence (uniform_block.common.name_matching).
+            shaderObject->MarkAsDeleted();
+            ReleaseShaderNameIfOrphaned(shader);
         }
     }
 
+    Bool ProgramState::ShaderHasGLVisibleAttachment(const SharedPtr<ShaderObject>& shaderObject) const {
+        for (const auto& programObject : m_programObjects) {
+            if (programObject != nullptr && programObject->ShaderIsAttachedGLVisible(shaderObject)) {
+                return true;
+            }
+        }
+        // A program deleted while current vacates its table slot but stays alive as the
+        // current program; its attachments still count.
+        return m_currentProgram != nullptr && m_currentProgram->ShaderIsAttachedGLVisible(shaderObject);
+    }
+
+    void ProgramState::ReleaseShaderNameIfOrphaned(Uint shader) {
+        if (!CheckIndexAvail(shader, m_shaderObjects)) return;
+        auto& shaderObject = m_shaderObjects[shader];
+        if (shaderObject == nullptr || !shaderObject->GetDeleteStatus()) return;
+        if (ShaderHasGLVisibleAttachment(shaderObject)) return;
+        shaderObject.reset();
+        m_shaderIndexGenerator.Delete(shader);
+    }
+
     Bool ProgramState::ValidateShaderObject(Uint shader) const {
         return CheckIndexAvail(shader, m_shaderObjects) && m_shaderObjects[shader] != nullptr;
     }

MobileGL/MG_State/GLState/ProgramState/ProgramState.h

@@ -26,11 +26,16 @@ namespace MobileGL::MG_State::GLState {
         Uint CreateShader(ShaderStage stage);
         const SharedPtr<ShaderObject>& GetShaderObject(Uint shader);
         void MarkShaderObjectForDeletion(Uint shader);
+        // Frees a deletion-flagged shader's name once no program holds a GL-visible
+        // attachment to it (the deferred half of glDeleteShader-while-attached).
+        void ReleaseShaderNameIfOrphaned(Uint shader);
         Bool ValidateShaderObject(Uint shader) const;
 
         const SharedPtr<ProgramObject>& GetCurrentProgram() const { return m_currentProgram; }
 
     private:
+        Bool ShaderHasGLVisibleAttachment(const SharedPtr<ShaderObject>& shaderObject) const;
+
         template <typename T>
         static Bool CheckIndexAvail(const SizeT idx, const Vector<T>& vec) {
             return idx < vec.size();

MobileGL/MG_State/GLState/TextureState/MipmapStorage.cpp

@@ -16,17 +16,32 @@ namespace MobileGL {
             }
 
             void MipmapStorage::AllocateLevel(Uint level, MipmapInput input) {
-                m_data.reserve(std::bit_ceil(level + 1));
-                m_data.resize(level + 1);
-                m_texelSizes.reserve(std::bit_ceil(level + 1));
-                m_texelSizes.resize(level + 1);
-                m_texelSizes[level] = input.texelSize;
-                m_isDirty.resize(level + 1, false);
+                // Grow only. GL respecifies exactly the level it is handed, so allocating level 0
+                // must not disturb the levels above it - but resize() shrinks as readily as it
+                // grows, so this used to truncate the whole chain to a single level. Callers that
+                // genuinely redefine the complete level set say so with TruncateToLevelCount.
+                const SizeT requiredLevelCount = static_cast<SizeT>(level) + 1;
+                if (m_data.size() < requiredLevelCount) {
+                    m_data.reserve(std::bit_ceil(requiredLevelCount));
+                    m_data.resize(requiredLevelCount);
+                    m_texelSizes.reserve(std::bit_ceil(requiredLevelCount));
+                    m_texelSizes.resize(requiredLevelCount);
+                    m_isDirty.resize(requiredLevelCount, false);
+                }
 
+                m_texelSizes[level] = input.texelSize;
                 auto& data = m_data[level];
                 data.resize(input.byteSize, 0);
             }
 
+            void MipmapStorage::TruncateToLevelCount(SizeT levelCount) {
+                if (levelCount >= m_data.size()) return;
+
+                m_data.resize(levelCount);
+                m_texelSizes.resize(levelCount);
+                m_isDirty.resize(levelCount);
+            }
+
             void MipmapStorage::UpdateSubData(Uint level, DataPtr input) {
                 auto& targetData = m_data;
                 MOBILEGL_ASSERT(level < targetData.size(), "UpdateSubData: level out of range");
@@ -55,6 +70,7 @@ namespace MobileGL {
             }
 
             SizeT MipmapStorage::GetByteSize(Uint level) const {
+                if (level >= m_data.size()) return 0;
                 return m_data[level].size();
             }
 

MobileGL/MG_State/GLState/TextureState/MipmapStorage.h

@@ -19,6 +19,10 @@ namespace MobileGL {
             public:
                 SizeT GetLevelCount() const;
                 void AllocateLevel(Uint level, MipmapInput input);
+                // Discard every level at or above levelCount. AllocateLevel never shrinks, so this
+                // is the only way a chain gets shorter - use it where the caller defines the whole
+                // level set (glTexStorage*, mip regeneration, atlas respecification).
+                void TruncateToLevelCount(SizeT levelCount);
                 void UpdateSubData(Uint level, DataPtr input);
                 void* MapData(Uint level);
                 IntVec3 GetTexelSize(Uint level) const;

MobileGL/MG_State/GLState/TextureState/MipmapUploadTargetArray.h

@@ -29,6 +29,14 @@ namespace MobileGL {
                     m_storage[targetIndex].AllocateLevel(level, input);
                 }
 
+                // Per-target, like AllocateLevel: cube-map faces are respecified independently, so
+                // truncating one face must not disturb the others.
+                void TruncateToLevelCount(Uint targetIndex, SizeT levelCount) {
+                    MOBILEGL_ASSERT(targetIndex < TargetCount, "TruncateToLevelCount: target invalid");
+
+                    m_storage[targetIndex].TruncateToLevelCount(levelCount);
+                }
+
                 void UpdateSubData(Uint targetIndex, Uint level, DataPtr input) {
                     MOBILEGL_ASSERT(targetIndex < TargetCount, "UpdateSubData: target invalid");
                     m_storage[targetIndex].UpdateSubData(level, input);

MobileGL/MG_State/GLState/TextureState/TextureEnum.h

@@ -76,6 +76,14 @@ namespace MobileGL {
         BGRInteger,
         RGBAInteger,
         BGRAInteger,
+        // Desktop-GL single-channel client formats (table 3.3): the data holds one component that
+        // feeds the G, B or A channel; the remaining channels default to 0 (color) / 1 (alpha).
+        Green,
+        Blue,
+        Alpha,
+        GreenInteger,
+        BlueInteger,
+        AlphaInteger,
         StencilIndex,
         DepthComponent,
         DepthStencil,

MobileGL/MG_State/GLState/TextureState/TextureObject.cpp

@@ -7,6 +7,7 @@
 // End of Source File Header
 
 #include "TextureObject.h"
+#include "MG_State/GLState/Core.h"
 #include "MG_Util/Types.h"
 #include <MG_Util/Metrics/TextureMetrics.h>
 
@@ -52,6 +53,20 @@ namespace MobileGL {
             void TextureObjectBase::SetInternalFormat(TextureInternalFormat format) {
                 if (format == m_internalFormat) return;
 
+                // A default texture (name 0) changes IsUndefinedDefaultTexture on the
+                // Unknown<->defined transition, which changes per-draw sampled-set membership
+                // without any bind happening; bump the bind generation so cached sampled sets
+                // re-resolve instead of replaying the stale membership. The identity check
+                // excludes the other externalIndex-0 objects (proxy textures, default-FBO
+                // attachments) whose definedness never feeds sampled-set membership, so e.g.
+                // proxy probes cannot churn the cache.
+                if (m_externalIndex == 0 && pGLContext &&
+                    (m_internalFormat == TextureInternalFormat::Unknown) !=
+                        (format == TextureInternalFormat::Unknown) &&
+                    pGLContext->GetDefaultTextureObject(GetTarget()).get() == this) {
+                    pGLContext->BumpTextureBindGeneration();
+                }
+
                 m_internalFormat = format;
                 ++m_textureParamsVersion;
             }
@@ -256,6 +271,10 @@ namespace MobileGL {
                 m_textureStorage.AllocateLevel(GetIndexOfTextureUploadTarget(uploadTarget), mipmapLevel, input);
             }
 
+            void TextureObjectWithOneMipmap::TruncateMipmapLevels(TextureUploadTarget uploadTarget, Uint levelCount) {
+                m_textureStorage.TruncateToLevelCount(GetIndexOfTextureUploadTarget(uploadTarget), levelCount);
+            }
+
             void TextureObjectWithOneMipmap::UpdateMipmapSubData(TextureUploadTarget uploadTarget, Uint mipmapLevel,
                                                                  DataPtr input) {
                 m_textureStorage.UpdateSubData(GetIndexOfTextureUploadTarget(uploadTarget), mipmapLevel, input);

MobileGL/MG_State/GLState/TextureState/TextureObject.h

@@ -134,6 +134,10 @@ namespace MobileGL::MG_State::GLState {
         virtual const IntVec3 GetMipmapTexelSize(TextureUploadTarget target, Uint mipmapLevel) const = 0;
         virtual const SizeT GetMipmapByteSize(TextureUploadTarget target, Uint mipmapLevel) const = 0;
         virtual void AllocateStorage(TextureUploadTarget uploadTarget, Uint mipmapLevel, MipmapInput input) = 0;
+        // AllocateStorage only ever grows the chain. Callers that define the complete level set -
+        // glTexStorage*, mip regeneration, or a level-0 respecification at a new size - drop the
+        // leftovers explicitly, so a stale tail can never make the texture silently incomplete.
+        virtual void TruncateMipmapLevels(TextureUploadTarget uploadTarget, Uint levelCount) = 0;
         virtual void UpdateMipmapSubData(TextureUploadTarget uploadTarget, Uint mipmapLevel, DataPtr input) = 0;
         virtual void* MapMipmapData(TextureUploadTarget uploadTarget, Uint mipmapLevel) = 0;
         virtual void MarkStorageDirty(TextureUploadTarget uploadTarget, Uint mipmapLevel, Bool dirty = true) = 0;
@@ -154,6 +158,17 @@ namespace MobileGL::MG_State::GLState {
                    : nullptr;
     }
 
+    // The per-target default texture objects (name 0) sit permanently in every texture unit's
+    // binding slots, so "nothing useful bound" is no longer a null slot. While a default texture
+    // has never been given an image (its internal format is still Unknown) it can contribute
+    // nothing to sampling; backends treat such a binding exactly like the old empty slot and
+    // skip per-draw sync/bind work for it. Once an application defines an image on a default
+    // texture it loses this shortcut and is synced like any other texture.
+    inline Bool IsUndefinedDefaultTexture(const ITextureObject* texture) {
+        return texture != nullptr && texture->GetExternalIndex() == 0 &&
+               texture->GetFormat() == TextureInternalFormat::Unknown;
+    }
+
     class TextureObjectWithOneMipmap : public TextureObjectMipmap {
     public:
         TextureObjectWithOneMipmap(TextureTarget target, Uint externalIndex)
@@ -164,6 +179,7 @@ namespace MobileGL::MG_State::GLState {
         const IntVec3 GetMipmapTexelSize(TextureUploadTarget target, Uint mipmapLevel) const override;
         const SizeT GetMipmapByteSize(TextureUploadTarget target, Uint mipmapLevel) const override;
         void AllocateStorage(TextureUploadTarget uploadTarget, Uint mipmapLevel, MipmapInput input) override;
+        void TruncateMipmapLevels(TextureUploadTarget uploadTarget, Uint levelCount) override;
         void UpdateMipmapSubData(TextureUploadTarget uploadTarget, Uint mipmapLevel, DataPtr input) override;
         void* MapMipmapData(TextureUploadTarget uploadTarget, Uint mipmapLevel) override;
         void MarkStorageDirty(TextureUploadTarget uploadTarget, Uint mipmapLevel, Bool dirty) override;

MobileGL/MG_State/GLState/TextureState/TextureObject2DCube.cpp

@@ -31,6 +31,10 @@ namespace MobileGL {
                 m_textureStorage.AllocateLevel(GetIndexOfTextureUploadTarget(uploadTarget), mipmapLevel, input);
             }
 
+            void TextureObject2DCube::TruncateMipmapLevels(TextureUploadTarget uploadTarget, Uint levelCount) {
+                m_textureStorage.TruncateToLevelCount(GetIndexOfTextureUploadTarget(uploadTarget), levelCount);
+            }
+
             void TextureObject2DCube::UpdateMipmapSubData(TextureUploadTarget uploadTarget, Uint mipmapLevel,
                                                           DataPtr input) {
                 m_textureStorage.UpdateSubData(GetIndexOfTextureUploadTarget(uploadTarget), mipmapLevel, input);

MobileGL/MG_State/GLState/TextureState/TextureObject2DCube.h

@@ -22,6 +22,7 @@ namespace MobileGL {
                 const IntVec3 GetMipmapTexelSize(TextureUploadTarget target, Uint mipmapLevel) const override;
                 const SizeT GetMipmapByteSize(TextureUploadTarget target, Uint mipmapLevel) const override;
                 void AllocateStorage(TextureUploadTarget uploadTarget, Uint mipmapLevel, MipmapInput input) override;
+                void TruncateMipmapLevels(TextureUploadTarget uploadTarget, Uint levelCount) override;
                 void UpdateMipmapSubData(TextureUploadTarget uploadTarget, Uint mipmapLevel, DataPtr input) override;
                 void* MapMipmapData(TextureUploadTarget uploadTarget, Uint mipmapLevel) override;
                 void MarkStorageDirty(TextureUploadTarget uploadTarget, Uint mipmapLevel, bool dirty) override;

MobileGL/MG_State/GLState/TextureState/TextureState.cpp

@@ -18,9 +18,51 @@
 #include "TextureObjectStubs.h"
 
 namespace MobileGL::MG_State::GLState {
+    static SharedPtr<ITextureObject> MakeTextureObjectForTarget(Uint index, TextureTarget target) {
+        switch (target) {
+        case TextureTarget::Texture1D:
+            return MakeShared<TextureObject1D>(index);
+        case TextureTarget::TextureCubeMap:
+            return MakeShared<TextureObject2DCube>(index);
+        case TextureTarget::Texture2D:
+            return MakeShared<TextureObject2D>(index);
+        case TextureTarget::Texture3D:
+            return MakeShared<TextureObject3D>(index);
+        case TextureTarget::TextureBuffer:
+            return MakeShared<TextureObjectBuffer>(index);
+
+            // These texture types are still stubbed:
+        case TextureTarget::TextureRectangle:
+            return MakeShared<TextureObjectRectangle>(index);
+        case TextureTarget::Texture2DMultisample:
+            return MakeShared<TextureObject2DMultisample>(index);
+        case TextureTarget::Texture1DArray:
+            return MakeShared<TextureObject1DArray>(index);
+        case TextureTarget::Texture2DArray:
+            return MakeShared<TextureObject2DArray>(index);
+        case TextureTarget::TextureCubeMapArray:
+            return MakeShared<TextureObjectCubeMapArray>(index);
+        case TextureTarget::Texture2DMultisampleArray:
+            return MakeShared<TextureObject2DMultisampleArray>(index);
+        default:
+            MOBILEGL_ASSERT(false, "Unimplemented texture type when creating texture object!: %d", (int)target);
+            return nullptr;
+        }
+    }
+
     TextureState::TextureState() : m_indexGenerator(1024, 1) {
+        // GL 3.3 core 3.8: each target owns one default texture object (name 0) per context,
+        // shared across all texture units, and it is the initial binding of every unit/target
+        // slot. It is created outside m_textureObjects so name-based paths (glIsTexture,
+        // GenTextures/DeleteTextures, by-name DSA lookups) never see it.
+        for (int i = 0; i < (int)TextureTarget::TextureTargetCount; ++i) {
+            m_defaultTextureObjects[i] = MakeTextureObjectForTarget(0, static_cast<TextureTarget>(i));
+        }
         for (int i = 0; i < MAX_TEXTURE_IMAGE_UNITS; ++i) {
             m_textureUnits[i] = TextureUnit();
+            for (auto& bindingSlot : m_textureUnits[i].GetAllBindingSlots()) {
+                bindingSlot.Bind(m_defaultTextureObjects[(int)bindingSlot.GetTarget()]);
+            }
         }
     }
 
@@ -33,6 +75,12 @@ namespace MobileGL::MG_State::GLState {
         return nullTextureObject;
     }
 
+    const SharedPtr<ITextureObject>& TextureState::GetDefaultTextureObject(TextureTarget target) const {
+        MOBILEGL_ASSERT(target > TextureTarget::Unknown && target < TextureTarget::TextureTargetCount,
+                        "GetDefaultTextureObject: invalid texture target %d", (int)target);
+        return m_defaultTextureObjects[(int)target];
+    }
+
     void TextureState::GenerateNames(Uint number, Vector<Uint>& textures) {
         textures.resize(number);
         m_indexGenerator.Generate(number, textures.data());
@@ -40,52 +88,15 @@ namespace MobileGL::MG_State::GLState {
 
     const SharedPtr<ITextureObject>& TextureState::CreateTextureObject(Uint index, TextureTarget target) {
         auto& textureObject = m_textureObjects[index];
-        switch (target) {
-        case TextureTarget::Texture1D:
-            textureObject = MakeShared<TextureObject1D>(index);
-            break;
-        case TextureTarget::TextureCubeMap:
-            textureObject = MakeShared<TextureObject2DCube>(index);
-            break;
-        case TextureTarget::Texture2D:
-            textureObject = MakeShared<TextureObject2D>(index);
-            break;
-        case TextureTarget::Texture3D:
-            textureObject = MakeShared<TextureObject3D>(index);
-            break;
-        case TextureTarget::TextureBuffer:
-            textureObject = MakeShared<TextureObjectBuffer>(index);
-            break;
-
-            // These texture types are still stubbed:
-        case TextureTarget::TextureRectangle:
-            textureObject = MakeShared<TextureObjectRectangle>(index);
-            break;
-        case TextureTarget::Texture2DMultisample:
-            textureObject = MakeShared<TextureObject2DMultisample>(index);
-            break;
-        case TextureTarget::Texture1DArray:
-            textureObject = MakeShared<TextureObject1DArray>(index);
-            break;
-        case TextureTarget::Texture2DArray:
-            textureObject = MakeShared<TextureObject2DArray>(index);
-            break;
-        case TextureTarget::TextureCubeMapArray:
-            textureObject = MakeShared<TextureObjectCubeMapArray>(index);
-            break;
-        case TextureTarget::Texture2DMultisampleArray:
-            textureObject = MakeShared<TextureObject2DMultisampleArray>(index);
-            break;
-        default:
-            MOBILEGL_ASSERT(false, "Unimplemented texture type when creating texture object!: %d", (int)target);
+        textureObject = MakeTextureObjectForTarget(index, target);
+        if (!textureObject) {
             static SharedPtr<ITextureObject> nullTextureObject = nullptr;
             return nullTextureObject;
         }
-
         return textureObject;
     }
 
-    void TextureState::MarkTextureObjectForDeletion(Uint index) {
+    void TextureState::MarkTextureObjectForDeletion(Uint index, Bool keepUnboundReservation) {
         if (m_indexGenerator.IsValid(index)) {
             auto it = m_textureObjects.find(index);
             if (it != m_textureObjects.end()) {
@@ -94,7 +105,9 @@ namespace MobileGL::MG_State::GLState {
                     auto& bindingSlots = m_textureUnits[unit].GetAllBindingSlots();
                     for (auto& bindingSlot : bindingSlots) {
                         if (bindingSlot.GetBoundObject() == it->second) {
-                            bindingSlot.Bind(nullptr);
+                            // GL 3.3 core 3.8.1: deleting a bound texture rebinds zero, i.e. the
+                            // target's default texture object, on every unit it was bound to.
+                            bindingSlot.Bind(m_defaultTextureObjects[(int)bindingSlot.GetTarget()]);
                         }
                     }
                 }
@@ -110,7 +123,15 @@ namespace MobileGL::MG_State::GLState {
                 BumpTextureBindGeneration();
                 m_textureObjects.erase(index);
                 m_indexGenerator.Delete(index);
+            } else if (!keepUnboundReservation) {
+                // GL 3.3 core 3.8.1 makes a deleted name unused again even when GenTextures only
+                // reserved it and no bind ever instantiated an object (so a later bind of it must
+                // fail), and the reservation has to return to the free list.
+                m_indexGenerator.Delete(index);
             }
+            // Relaxed semantics: legacy apps may delete a generated name before its first
+            // bind, then bind and populate that same name. Keep such a reservation alive there;
+            // a real texture object reaching deletion still releases its index above.
         }
     }
 

MobileGL/MG_State/GLState/TextureState/TextureState.h

@@ -49,12 +49,18 @@ namespace MobileGL::MG_State::GLState {
         void GenerateNames(Uint number, Vector<Uint>& textures);
         const SharedPtr<ITextureObject>& CreateTextureObject(Uint index, TextureTarget target);
         const SharedPtr<ITextureObject>& GetTextureObject(Uint index);
+        // The context's default texture object (name 0) for `target`. GL 3.3 core 3.8: texture
+        // zero names a real, per-target texture object shared by every texture unit; binding 0
+        // binds it, and image/parameter calls on it must work like on any texture. It is not a
+        // GenTextures name: it lives outside m_textureObjects (so glIsTexture(0) stays GL_FALSE
+        // and by-name lookups keep failing for 0) and can never be deleted.
+        const SharedPtr<ITextureObject>& GetDefaultTextureObject(TextureTarget target) const;
         TextureUnit& GetUnitObject(Int unit);
         ImageTextureBinding& GetImageTextureBinding(Int unit);
         const ImageTextureBinding& GetImageTextureBinding(Int unit) const;
         Int GetActiveTextureUnit() const;
         void SetActiveTextureUnit(Int unit);
-        void MarkTextureObjectForDeletion(Uint index);
+        void MarkTextureObjectForDeletion(Uint index, Bool keepUnboundReservation);
         Bool ValidateName(Uint index) const;
         Bool ValidateTextureObject(Uint index) const;
 
@@ -83,5 +89,8 @@ namespace MobileGL::MG_State::GLState {
         Array<ImageTextureBinding, MAX_TEXTURE_IMAGE_UNITS> m_imageTextureBindings;
         IndexGenerator<Uint> m_indexGenerator;
         UnorderedMap<GLuint, SharedPtr<ITextureObject>> m_textureObjects;
+        // One default texture object (external name 0) per target, created with the context and
+        // immortal for its lifetime; the initial binding of every unit/target slot.
+        Array<SharedPtr<ITextureObject>, (int)TextureTarget::TextureTargetCount> m_defaultTextureObjects;
     };
 } // namespace MobileGL::MG_State::GLState

MobileGL/MG_Test/Backend/DirectVulkan/CMakeLists.txt

@@ -40,10 +40,16 @@ if (APPLE)
     target_link_libraries(DirectVulkanSanityTest PRIVATE objc)
     target_link_libraries(DirectVulkanSanityTest PRIVATE ${QUARTZCORE_FRAMEWORK})
 endif()
+if (MSVC)
+    # The GLES headers declare gl* as dllimport on Windows, so objects like GetProcAddress.cpp
+    # reference __imp_gl*. Those resolve against the in-library GL entry-point definitions only
+    # if their objects are part of the link; pull the whole static library like the DLL does.
+    target_link_options(DirectVulkanSanityTest PRIVATE /WHOLEARCHIVE:MobileGL_s)
+endif()
 target_compile_definitions(DirectVulkanSanityTest PRIVATE -DNOMINMAX)
 
 include(GoogleTest)
-gtest_discover_tests(DirectVulkanSanityTest DISCOVERY_TIMEOUT 30)
+gtest_discover_tests(DirectVulkanSanityTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS integration)
 
 add_executable(
         DirectVulkanTestExec

MobileGL/MG_Test/BackendLoader/BackendLoaderTest.cpp

@@ -12,6 +12,10 @@
 #include <string>
 #include <vector>
 
+#include <algorithm>
+
+#include <MG_Backend/DirectGLES/BackendObject_DirectGLES.h>
+#include <MG_Backend/DirectVulkan/BackendObject_DirectVulkan.h>
 #include <MG_Util/BackendLoaders/OpenGL/Loader.h>
 
 // ProbeIndirectInstanceIdIncludesBaseInstance is driven against a fake GLES driver:
@@ -23,6 +27,13 @@ namespace {
     struct FakeDriverState {
         // Behavior knobs, configured per test before running the probe.
         GLint maxVertexSsboBlocks = 4;
+        GLint glesMajorVersion = 3;
+        GLint glesMinorVersion = 1;
+        GLint maxVertexImageUniforms = 2;
+        GLint maxGeometryImageUniforms = 3;
+        GLint maxFragmentImageUniforms = 4;
+        GLint maxComputeImageUniforms = 5;
+        bool maxGeometryImageUniformsQueried = false;
         // Emulates ANGLE-on-Vulkan: the draw reads the indirect command's
         // baseInstance word and exposes it through gl_InstanceID.
         bool drawLeaksBaseInstanceWord = false;
@@ -31,6 +42,11 @@ namespace {
         GLenum pendingError = GL_NO_ERROR;
         std::vector<std::string> extensions;
 
+        // GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT the fake reports, and whether it was ever asked:
+        // querying it on a driver without the extension would raise GL_INVALID_ENUM.
+        GLfloat maxTextureMaxAnisotropy = 16.0f;
+        bool maxTextureMaxAnisotropyQueried = false;
+
         GLuint nextBufferId = 1;
         GLuint nextShaderId = 1;
         GLuint nextProgramId = 1;
@@ -79,13 +95,26 @@ namespace {
             case GL_MAX_VERTEX_SHADER_STORAGE_BLOCKS:
                 *data = g_fake.maxVertexSsboBlocks;
                 break;
+            case GL_MAX_VERTEX_IMAGE_UNIFORMS:
+                *data = g_fake.maxVertexImageUniforms;
+                break;
+            case GL_MAX_GEOMETRY_IMAGE_UNIFORMS:
+                g_fake.maxGeometryImageUniformsQueried = true;
+                *data = g_fake.maxGeometryImageUniforms;
+                break;
+            case GL_MAX_FRAGMENT_IMAGE_UNIFORMS:
+                *data = g_fake.maxFragmentImageUniforms;
+                break;
+            case GL_MAX_COMPUTE_IMAGE_UNIFORMS:
+                *data = g_fake.maxComputeImageUniforms;
+                break;
             // FillInGLESCapabilities reads the context version before running the
             // baseInstance probe, which requires ES >= 3.1.
             case GL_MAJOR_VERSION:
-                *data = 3;
+                *data = g_fake.glesMajorVersion;
                 break;
             case GL_MINOR_VERSION:
-                *data = 1;
+                *data = g_fake.glesMinorVersion;
                 break;
             case GL_NUM_EXTENSIONS:
                 *data = static_cast<GLint>(g_fake.extensions.size());
@@ -122,6 +151,10 @@ namespace {
         };
         funcs.glGetFloatv = [](GLenum pname, GLfloat* data) {
             switch (pname) {
+            case GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT:
+                g_fake.maxTextureMaxAnisotropyQueried = true;
+                data[0] = g_fake.maxTextureMaxAnisotropy;
+                break;
             // Two-component range queries.
             case GL_ALIASED_LINE_WIDTH_RANGE:
             case GL_SMOOTH_LINE_WIDTH_RANGE:
@@ -404,6 +437,76 @@ TEST(IndirectInstanceIdProbe, FillInCapabilitiesWiresProbeResult) {
     ExpectProbeReleasedAllObjects();
 }
 
+TEST(ImageUniformCapabilities, QueriesRealPerStageLimitsAndConservativelyGatesGeometry) {
+    const auto funcs = MakeFakeGLESFunctions();
+
+    ResetFakeDriver();
+    g_fake.maxVertexSsboBlocks = 0;
+    MobileGL::MG_External::GLESCapabilities es31Caps;
+    ASSERT_TRUE(MobileGL::MG_Util::BackendLoader::FillInGLESCapabilities(es31Caps, funcs));
+    EXPECT_EQ(es31Caps.MaxVertexImageUniforms, g_fake.maxVertexImageUniforms);
+    EXPECT_EQ(es31Caps.MaxGeometryImageUniforms, 0);
+    EXPECT_EQ(es31Caps.MaxFragmentImageUniforms, g_fake.maxFragmentImageUniforms);
+    EXPECT_EQ(es31Caps.MaxComputeImageUniforms, g_fake.maxComputeImageUniforms);
+    EXPECT_FALSE(g_fake.maxGeometryImageUniformsQueried);
+
+    ResetFakeDriver();
+    g_fake.maxVertexSsboBlocks = 0;
+    g_fake.glesMinorVersion = 2;
+    MobileGL::MG_External::GLESCapabilities es32Caps;
+    ASSERT_TRUE(MobileGL::MG_Util::BackendLoader::FillInGLESCapabilities(es32Caps, funcs));
+    EXPECT_EQ(es32Caps.MaxVertexImageUniforms, g_fake.maxVertexImageUniforms);
+    EXPECT_EQ(es32Caps.MaxGeometryImageUniforms, g_fake.maxGeometryImageUniforms);
+    EXPECT_EQ(es32Caps.MaxFragmentImageUniforms, g_fake.maxFragmentImageUniforms);
+    EXPECT_EQ(es32Caps.MaxComputeImageUniforms, g_fake.maxComputeImageUniforms);
+    EXPECT_TRUE(g_fake.maxGeometryImageUniformsQueried);
+}
+
+// The extension string is what apps gate on (LWJGL builds GLCapabilities from it), so advertising
+// it on a driver that cannot filter anisotropically would leave them silently on trilinear.
+TEST(TextureAnisotropyCapabilities, ExtensionIsAdvertisedOnlyWhenTheHostDriverSupportsIt) {
+    const auto contains = [](const MobileGL::Vector<MobileGL::GLExtension>& extensions,
+                             MobileGL::GLExtension wanted) {
+        return std::find(extensions.begin(), extensions.end(), wanted) != extensions.end();
+    };
+
+    const auto without = MobileGL::MG_Backend::DirectGLES::BuildAdvertisedExtensions(false, false);
+    EXPECT_FALSE(contains(without, MobileGL::E_GL_EXT_texture_filter_anisotropic));
+    EXPECT_FALSE(contains(without, MobileGL::E_GL_ARB_texture_filter_anisotropic));
+
+    const auto with = MobileGL::MG_Backend::DirectGLES::BuildAdvertisedExtensions(false, true);
+    EXPECT_TRUE(contains(with, MobileGL::E_GL_EXT_texture_filter_anisotropic));
+    EXPECT_TRUE(contains(with, MobileGL::E_GL_ARB_texture_filter_anisotropic));
+
+    // Same rule on the Vulkan backend, where the gate is the samplerAnisotropy device feature.
+    const auto vkWithout = MobileGL::MG_Backend::DirectVulkan::BuildAdvertisedExtensions(false, false, false);
+    EXPECT_FALSE(contains(vkWithout, MobileGL::E_GL_EXT_texture_filter_anisotropic));
+    const auto vkWith = MobileGL::MG_Backend::DirectVulkan::BuildAdvertisedExtensions(false, false, true);
+    EXPECT_TRUE(contains(vkWith, MobileGL::E_GL_EXT_texture_filter_anisotropic));
+    EXPECT_TRUE(contains(vkWith, MobileGL::E_GL_ARB_texture_filter_anisotropic));
+}
+
+TEST(TextureAnisotropyCapabilities, MaxAnisotropyIsQueriedOnlyWhenTheExtensionIsPresent) {
+    ResetFakeDriver();
+    g_fake.maxVertexSsboBlocks = 0;
+    const auto funcs = MakeFakeGLESFunctions();
+
+    MobileGL::MG_External::GLESCapabilities absentCaps;
+    ASSERT_TRUE(MobileGL::MG_Util::BackendLoader::FillInGLESCapabilities(absentCaps, funcs));
+    // Never probed (it would be GL_INVALID_ENUM), and reported as "no anisotropy".
+    EXPECT_FALSE(g_fake.maxTextureMaxAnisotropyQueried);
+    EXPECT_FLOAT_EQ(absentCaps.MaxTextureMaxAnisotropy, 1.0f);
+
+    ResetFakeDriver();
+    g_fake.maxVertexSsboBlocks = 0;
+    g_fake.maxTextureMaxAnisotropy = 16.0f;
+    g_fake.extensions.emplace_back("GL_EXT_texture_filter_anisotropic");
+    MobileGL::MG_External::GLESCapabilities presentCaps;
+    ASSERT_TRUE(MobileGL::MG_Util::BackendLoader::FillInGLESCapabilities(presentCaps, funcs));
+    EXPECT_TRUE(g_fake.maxTextureMaxAnisotropyQueried);
+    EXPECT_FLOAT_EQ(presentCaps.MaxTextureMaxAnisotropy, 16.0f);
+}
+
 TEST(TextureAnisotropyCapabilities, ExtensionPresenceIsDetectedExactly) {
     ResetFakeDriver();
     g_fake.maxVertexSsboBlocks = 0;

MobileGL/MG_Test/BackendLoader/CMakeLists.txt

@@ -17,4 +17,4 @@ target_link_libraries(
 )
 
 include(GoogleTest)
-gtest_discover_tests(BackendLoaderTest DISCOVERY_TIMEOUT 30)
+gtest_discover_tests(BackendLoaderTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)

MobileGL/MG_Test/Buffer/BufferTest.cpp

@@ -8,6 +8,8 @@
 
 #include <gtest/gtest.h>
 
+#include <limits>
+
 #include "Includes.h"
 #include "Init.h"
 #include <Config.h>
@@ -20,9 +22,31 @@ using namespace MobileGL;
 
 class BufferTest : public ::testing::Test {
 protected:
-    void SetUp() override { MobileGL::Initialize(); }
+    // GL error flags are sticky per error code and the context outlives an individual test in this
+    // binary, so drain whatever an earlier test left pending - otherwise an error-code assertion
+    // here reads someone else's error. Bounded: one flag per code, so this cannot hang the suite.
+    static void DrainPendingGlErrors() {
+        for (Int drained = 0; drained < 16 && MG_Impl::GLImpl::GetError() != GL_NO_ERROR; ++drained) {
+        }
+    }
 
-    void TearDown() override {}
+    // The call under test must raise exactly the expected error and nothing more: a second pending
+    // error means one entry point queued several, which GetError() would hand out at an unrelated
+    // call site later on.
+    static void ExpectSingleGlError(GLenum expected) {
+        EXPECT_EQ(MG_Impl::GLImpl::GetError(), expected);
+        EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR) << "the call recorded more than one error";
+    }
+
+    void SetUp() override {
+        MobileGL::Initialize();
+        DrainPendingGlErrors();
+    }
+
+    void TearDown() override {
+        // Attribute a leaked error to the test that caused it instead of to whoever runs next.
+        EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR) << "test left an unconsumed GL error behind";
+    }
 };
 
 TEST_F(BufferTest, Binding) {
@@ -105,6 +129,53 @@ TEST_F(BufferTest, GenerateManyNames_NoPrematureCreation) {
     }
 }
 
+// GL 3.3 core 2.9 name lifecycle. The same three rules are asserted per object family (see the
+// texture/vertex-array/framebuffer/renderbuffer suites): a deleted or never-generated name is
+// INVALID_OPERATION to bind, deleting one is silent, and a generated-but-never-bound reservation
+// is still released so the name gets recycled.
+TEST_F(BufferTest, DeleteOfUnknownOrAlreadyDeletedBufferNameIsSilent) {
+    GLuint buffer = 0;
+    MG_Impl::GLImpl::GenBuffers(1, &buffer);
+    ASSERT_NE(buffer, 0u);
+    ASSERT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    MG_Impl::GLImpl::DeleteBuffers(1, &buffer);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    // Double delete, name 0 and a never-generated name must all be ignored without an error.
+    MG_Impl::GLImpl::DeleteBuffers(1, &buffer);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    const GLuint unknownNames[] = {0u, std::numeric_limits<GLuint>::max()};
+    MG_Impl::GLImpl::DeleteBuffers(2, unknownNames);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+}
+
+TEST_F(BufferTest, DeleteGeneratedButUnboundBufferNameReleasesReservationAndBindFails) {
+    GLuint buffer = 0;
+    MG_Impl::GLImpl::GenBuffers(1, &buffer);
+    ASSERT_NE(buffer, 0u);
+    ASSERT_TRUE(MG_State::pGLContext->ValidateBufferName(buffer));
+
+    MG_Impl::GLImpl::DeleteBuffers(1, &buffer);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+    EXPECT_FALSE(MG_State::pGLContext->ValidateBufferName(buffer));
+
+    MG_Impl::GLImpl::BindBuffer(GL_ARRAY_BUFFER, buffer);
+    ExpectSingleGlError(GL_INVALID_OPERATION);
+
+    GLuint recycled = 0;
+    MG_Impl::GLImpl::GenBuffers(1, &recycled);
+    EXPECT_EQ(recycled, buffer);
+}
+
+TEST_F(BufferTest, BindNeverGeneratedBufferNameIsInvalidOperation) {
+    // Not a small literal: other tests in this binary share the context and generate names in
+    // bulk, so a low number may well be a legitimately reserved name here.
+    MG_Impl::GLImpl::BindBuffer(GL_ARRAY_BUFFER, std::numeric_limits<GLuint>::max());
+    ExpectSingleGlError(GL_INVALID_OPERATION);
+}
+
 TEST_F(BufferTest, AcquireMemory) {
     auto& slot = MobileGL::MG_State::pGLContext->GetBufferBindingSlot(BufferTarget::Uniform);
     Vector<Uint> bufferNames;

MobileGL/MG_Test/Buffer/CMakeLists.txt

@@ -24,4 +24,4 @@ if (MSVC)
 endif()
 
 include(GoogleTest)
-gtest_discover_tests(BufferTest DISCOVERY_TIMEOUT 30)
+gtest_discover_tests(BufferTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)

MobileGL/MG_Test/CMakeLists.txt

@@ -62,7 +62,7 @@ set(LINK_LIBRARIES
 )
 
 include(GoogleTest)
-gtest_discover_tests(SanityTest DISCOVERY_TIMEOUT 30)
+gtest_discover_tests(SanityTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)
 
 add_subdirectory(BackendLoader)
 add_subdirectory(Buffer)
@@ -72,6 +72,8 @@ add_subdirectory(Texture)
 add_subdirectory(VertexArray)
 add_subdirectory(Program)
 add_subdirectory(Query)
+add_subdirectory(Pipeline)
+add_subdirectory(ShaderTranspiler)
 if (ENABLE_INTEGRATION_TESTS)
     add_subdirectory(Backend/DirectVulkan)
 endif()

MobileGL/MG_Test/EGLState/CMakeLists.txt

@@ -17,4 +17,4 @@ target_link_libraries(
 )
 
 include(GoogleTest)
-gtest_discover_tests(EGLStateTest DISCOVERY_TIMEOUT 30)
+gtest_discover_tests(EGLStateTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)

MobileGL/MG_Test/EGLState/EGLStateTest.cpp

@@ -102,3 +102,33 @@ TEST(EGLStateMakeCurrent, SameThreadRepeatedAttachReleaseDoesNotLeaveStaleOwner)
     EXPECT_TRUE(fixture->State.MakeCurrent(EGL_NO_DISPLAY, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT));
     EXPECT_EQ(fixture->State.ConsumeError(), EGL_SUCCESS);
 }
+
+// The compatibility-profile accessor is affirmative-only (it backs GL_CONTEXT_PROFILE_MASK
+// reporting): attrib-less contexts (profile mask 0) and released threads both answer "not
+// compat" and therefore read as core-profile contexts.
+TEST(EGLStateProfile, CompatibilityProfileRequiresExplicitCompatBit) {
+    auto fixture = CreateFixture();
+
+    EXPECT_FALSE(fixture->State.IsCurrentContextOpenGLCompatibilityProfile());
+
+    EXPECT_TRUE(fixture->State.MakeCurrent(fixture->Display, fixture->Surface, fixture->Surface, fixture->Context));
+    EXPECT_FALSE(fixture->State.IsCurrentContextOpenGLCompatibilityProfile());
+
+    const EGLint compatAttribs[] = {EGL_CONTEXT_MAJOR_VERSION,
+                                    3,
+                                    EGL_CONTEXT_MINOR_VERSION,
+                                    3,
+                                    EGL_CONTEXT_OPENGL_PROFILE_MASK,
+                                    EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT,
+                                    EGL_NONE};
+    const auto compatContext =
+        fixture->State.CreateContext(fixture->Display, fixture->Config, EGL_NO_CONTEXT, compatAttribs);
+    ASSERT_NE(compatContext, EGL_NO_CONTEXT);
+    EXPECT_TRUE(fixture->State.MakeCurrent(fixture->Display, fixture->Surface, fixture->Surface, compatContext));
+    EXPECT_TRUE(fixture->State.IsCurrentContextOpenGLCompatibilityProfile());
+    EXPECT_FALSE(fixture->State.IsCurrentContextOpenGLCoreProfile());
+
+    EXPECT_TRUE(fixture->State.MakeCurrent(EGL_NO_DISPLAY, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT));
+    EXPECT_FALSE(fixture->State.IsCurrentContextOpenGLCompatibilityProfile());
+    EXPECT_EQ(fixture->State.ConsumeError(), EGL_SUCCESS);
+}

MobileGL/MG_Test/Framebuffer/CMakeLists.txt

@@ -17,4 +17,4 @@ target_link_libraries(
 )
 
 include(GoogleTest)
-gtest_discover_tests(FramebufferTest DISCOVERY_TIMEOUT 30)
+gtest_discover_tests(FramebufferTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)

MobileGL/MG_Test/Framebuffer/FramebufferTest.cpp

@@ -8,9 +8,12 @@
 
 #include <gtest/gtest.h>
 
+#include <limits>
+
 #include "Includes.h"
 #include "Init.h"
 #include <MG_Backend/BackendObjects.h>
+#include <MG_Backend/DirectGLES/Utils.h>
 #include <MG_Impl/GLImpl/Buffer/GL_Buffer.h>
 #include <MG_Impl/GLImpl/Framebuffer/GL_Framebuffer.h>
 #include <MG_Impl/GLImpl/Getter/GL_Getter.h>
@@ -32,6 +35,8 @@ namespace {
     Int g_clearNamedFramebufferfvCallCount = 0;
     Int g_clearNamedFramebufferfiCallCount = 0;
     Int g_readPixelsCallCount = 0;
+    GLenum g_lastReadPixelsFormat = GL_NONE;
+    GLenum g_lastReadPixelsType = GL_NONE;
 
     void RecordBlitNamedFramebuffer(const SharedPtr<MG_State::GLState::FramebufferObject>& readFramebuffer,
                                     const SharedPtr<MG_State::GLState::FramebufferObject>& drawFramebuffer,
@@ -66,15 +71,39 @@ namespace {
         ++g_clearNamedFramebufferfiCallCount;
     }
 
-    void RecordReadPixels(GLint, GLint, GLsizei, GLsizei, GLenum, GLenum, void*) {
+    void RecordReadPixels(GLint, GLint, GLsizei, GLsizei, GLenum format, GLenum type, void*) {
         ++g_readPixelsCallCount;
+        g_lastReadPixelsFormat = format;
+        g_lastReadPixelsType = type;
     }
 } // namespace
 
 class FramebufferTest : public ::testing::Test {
 protected:
+    // GL error flags are sticky per error code and the context outlives an individual test in this
+    // binary, so drain whatever an earlier test left pending - otherwise an error-code assertion
+    // here reads someone else's error. Bounded: one flag per code, so this cannot hang the suite.
+    static void DrainPendingGlErrors() {
+        for (Int drained = 0; drained < 16 && MG_Impl::GLImpl::GetError() != GL_NO_ERROR; ++drained) {
+        }
+    }
+
+    // The call under test must raise exactly the expected error and nothing more: a second pending
+    // error means one entry point queued several, which GetError() would hand out at an unrelated
+    // call site later on.
+    static void ExpectSingleGlError(GLenum expected) {
+        EXPECT_EQ(MG_Impl::GLImpl::GetError(), expected);
+        EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR) << "the call recorded more than one error";
+    }
+
+    void TearDown() override {
+        // Attribute a leaked error to the test that caused it instead of to whoever runs next.
+        EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR) << "test left an unconsumed GL error behind";
+    }
+
     void SetUp() override {
         MobileGL::Initialize();
+        DrainPendingGlErrors();
         const auto defaultFramebuffer = MG_State::pGLContext->GetFramebufferObject(0);
         ASSERT_NE(defaultFramebuffer, nullptr);
         MG_State::pGLContext->GetFramebufferBindingSlot(FramebufferTarget::Draw).Bind(defaultFramebuffer);
@@ -97,6 +126,8 @@ protected:
         g_clearNamedFramebufferfvCallCount = 0;
         g_clearNamedFramebufferfiCallCount = 0;
         g_readPixelsCallCount = 0;
+        g_lastReadPixelsFormat = GL_NONE;
+        g_lastReadPixelsType = GL_NONE;
         MG_Backend::gBackendFunctionsTable.GL.BlitNamedFramebuffer = nullptr;
         MG_Backend::gBackendFunctionsTable.GL.ClearNamedFramebufferfv = nullptr;
         MG_Backend::gBackendFunctionsTable.GL.ClearNamedFramebufferfi = nullptr;
@@ -115,6 +146,83 @@ TEST_F(FramebufferTest, CreateFramebuffersCreatesObjectsImmediately) {
     EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
 }
 
+// GL 3.3 core 4.4.1/4.4.2 name lifecycle - mirrors the rules asserted for the other object
+// families: deleting an unknown name is silent, a released reservation is recycled, and binding
+// a dead name is INVALID_OPERATION.
+TEST_F(FramebufferTest, DeleteOfUnknownOrAlreadyDeletedFramebufferNameIsSilent) {
+    GLuint framebuffer = 0;
+    MG_Impl::GLImpl::GenFramebuffers(1, &framebuffer);
+    ASSERT_NE(framebuffer, 0u);
+    ASSERT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    MG_Impl::GLImpl::DeleteFramebuffers(1, &framebuffer);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    MG_Impl::GLImpl::DeleteFramebuffers(1, &framebuffer);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    // Not a small literal: other tests in this binary share the context and generate names in
+    // bulk, so a low number may well be a legitimately reserved name here.
+    const GLuint unknownNames[] = {0u, std::numeric_limits<GLuint>::max()};
+    MG_Impl::GLImpl::DeleteFramebuffers(2, unknownNames);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+}
+
+TEST_F(FramebufferTest, DeleteGeneratedButUnboundFramebufferNameReleasesReservationAndBindFails) {
+    GLuint framebuffer = 0;
+    MG_Impl::GLImpl::GenFramebuffers(1, &framebuffer);
+    ASSERT_NE(framebuffer, 0u);
+    ASSERT_TRUE(MG_State::pGLContext->ValidateFramebufferName(framebuffer));
+
+    MG_Impl::GLImpl::DeleteFramebuffers(1, &framebuffer);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+    EXPECT_FALSE(MG_State::pGLContext->ValidateFramebufferName(framebuffer));
+
+    MG_Impl::GLImpl::BindFramebuffer(GL_FRAMEBUFFER, framebuffer);
+    ExpectSingleGlError(GL_INVALID_OPERATION);
+
+    GLuint recycled = 0;
+    MG_Impl::GLImpl::GenFramebuffers(1, &recycled);
+    EXPECT_EQ(recycled, framebuffer);
+}
+
+TEST_F(FramebufferTest, DeleteOfUnknownOrAlreadyDeletedRenderbufferNameIsSilent) {
+    GLuint renderbuffer = 0;
+    MG_Impl::GLImpl::GenRenderbuffers(1, &renderbuffer);
+    ASSERT_NE(renderbuffer, 0u);
+    ASSERT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    MG_Impl::GLImpl::DeleteRenderbuffers(1, &renderbuffer);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    MG_Impl::GLImpl::DeleteRenderbuffers(1, &renderbuffer);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    // Not a small literal: other tests in this binary share the context and generate names in
+    // bulk, so a low number may well be a legitimately reserved name here.
+    const GLuint unknownNames[] = {0u, std::numeric_limits<GLuint>::max()};
+    MG_Impl::GLImpl::DeleteRenderbuffers(2, unknownNames);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+}
+
+TEST_F(FramebufferTest, DeleteGeneratedButUnboundRenderbufferNameReleasesReservationAndBindFails) {
+    GLuint renderbuffer = 0;
+    MG_Impl::GLImpl::GenRenderbuffers(1, &renderbuffer);
+    ASSERT_NE(renderbuffer, 0u);
+    ASSERT_TRUE(MG_State::pGLContext->ValidateRenderbufferName(renderbuffer));
+
+    MG_Impl::GLImpl::DeleteRenderbuffers(1, &renderbuffer);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+    EXPECT_FALSE(MG_State::pGLContext->ValidateRenderbufferName(renderbuffer));
+
+    MG_Impl::GLImpl::BindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
+    ExpectSingleGlError(GL_INVALID_OPERATION);
+
+    GLuint recycled = 0;
+    MG_Impl::GLImpl::GenRenderbuffers(1, &recycled);
+    EXPECT_EQ(recycled, renderbuffer);
+}
+
 TEST_F(FramebufferTest, DefaultFramebufferIdentityTracksFramebufferNameZero) {
     const auto defaultFramebuffer = MG_State::pGLContext->GetFramebufferObject(0);
     ASSERT_NE(defaultFramebuffer, nullptr);
@@ -221,6 +329,77 @@ TEST_F(FramebufferTest, ReadPixelsAllowsPersistentMappedPixelPackBuffer) {
     EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
 }
 
+TEST_F(FramebufferTest, ReadPixelsRejectsMismatchedPackedTypeFormatPairs) {
+    GLuint framebuffer = 0;
+    GLuint texture = 0;
+    MG_Impl::GLImpl::CreateFramebuffers(1, &framebuffer);
+    MG_Impl::GLImpl::CreateTextures(GL_TEXTURE_2D, 1, &texture);
+    MG_Impl::GLImpl::TextureStorage2D(texture, 1, GL_RGBA8, 4, 4);
+    MG_Impl::GLImpl::NamedFramebufferTexture(framebuffer, GL_COLOR_ATTACHMENT0, texture, 0);
+    MG_Impl::GLImpl::BindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
+
+    MG_Backend::gBackendFunctionsTable.GL.ReadPixels = RecordReadPixels;
+    Uint8 pixelStorage[4 * 4 * 4] = {};
+
+    // Packed RGB type with a non-RGB format must never reach the backend (GL CTS packed_pixels
+    // reads GL_RED with GL_UNSIGNED_SHORT_5_6_5 and expects an error).
+    MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, GL_RED, GL_UNSIGNED_SHORT_5_6_5, pixelStorage);
+    EXPECT_EQ(g_readPixelsCallCount, 0);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_INVALID_OPERATION);
+
+    // Packed RGBA type with a non-RGBA/BGRA format is rejected as well.
+    MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, GL_RGB, GL_UNSIGNED_INT_8_8_8_8, pixelStorage);
+    EXPECT_EQ(g_readPixelsCallCount, 0);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_INVALID_OPERATION);
+
+    // Packed depth-stencil type requires the DEPTH_STENCIL format.
+    MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, GL_RGBA, GL_UNSIGNED_INT_24_8, pixelStorage);
+    EXPECT_EQ(g_readPixelsCallCount, 0);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_INVALID_OPERATION);
+
+    // A plain RGBA/UNSIGNED_BYTE readback keeps working.
+    MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, GL_RGBA, GL_UNSIGNED_BYTE, pixelStorage);
+    EXPECT_EQ(g_readPixelsCallCount, 1);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+}
+
+TEST_F(FramebufferTest, ReadPixelsForwardsSingleChannelDesktopClientFormats) {
+    GLuint framebuffer = 0;
+    GLuint texture = 0;
+    MG_Impl::GLImpl::CreateFramebuffers(1, &framebuffer);
+    MG_Impl::GLImpl::CreateTextures(GL_TEXTURE_2D, 1, &texture);
+    MG_Impl::GLImpl::TextureStorage2D(texture, 1, GL_RGBA8, 4, 4);
+    MG_Impl::GLImpl::NamedFramebufferTexture(framebuffer, GL_COLOR_ATTACHMENT0, texture, 0);
+    MG_Impl::GLImpl::BindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
+
+    MG_Backend::gBackendFunctionsTable.GL.ReadPixels = RecordReadPixels;
+    Uint8 pixelStorage[4 * 4 * 4] = {};
+
+    // Desktop GL treats GL_GREEN/GL_BLUE/GL_ALPHA as valid ReadPixels client formats (GL CTS
+    // packed_pixels rgba8_format_green failed with GL_INVALID_ENUM before). The state layer must
+    // validate them and forward the raw enum to the backend, which extracts the source channel
+    // from a wide RGBA read.
+    const GLenum singleChannelFormats[] = {GL_GREEN, GL_BLUE, GL_ALPHA};
+    Int expectedCallCount = 0;
+    for (const GLenum format : singleChannelFormats) {
+        MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, format, GL_UNSIGNED_BYTE, pixelStorage);
+        EXPECT_EQ(g_readPixelsCallCount, ++expectedCallCount);
+        EXPECT_EQ(g_lastReadPixelsFormat, format);
+        EXPECT_EQ(g_lastReadPixelsType, static_cast<GLenum>(GL_UNSIGNED_BYTE));
+        EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+    }
+
+    // Packed-type pairing still applies: packed RGB/RGBA types never pair with single-channel formats.
+    MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, GL_GREEN, GL_UNSIGNED_SHORT_5_6_5, pixelStorage);
+    EXPECT_EQ(g_readPixelsCallCount, expectedCallCount);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_INVALID_OPERATION);
+
+    // Integer client formats reject floating-point types.
+    MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, GL_GREEN_INTEGER, GL_FLOAT, pixelStorage);
+    EXPECT_EQ(g_readPixelsCallCount, expectedCallCount);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_INVALID_OPERATION);
+}
+
 TEST_F(FramebufferTest, NamedRenderbufferStorageAndFramebufferAttachDoNotChangeBindings) {
     GLuint framebuffer = 0;
     GLuint renderbuffer = 0;
@@ -419,3 +598,263 @@ TEST_F(FramebufferTest, BlitNamedFramebufferAllowsDefaultFramebufferZero) {
     EXPECT_EQ(MG_State::pGLContext->GetFramebufferBindingSlot(FramebufferTarget::Read).GetBoundObject(), defaultRead);
     EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
 }
+
+// ---- Packed-type readback encoding ------------------------------------------------------------------
+// Oracle-independent guard for the DirectGLES client-format readback conversion: feeds known wide RGBA
+// rows through ReadbackImpl::ConvertWideReadbackRow and asserts the exact packed words. Field positions
+// were hand-computed from GL 3.3 table 3.6 and match the GL CTS packed_pixels comparison functions
+// (glcPackedPixelsTests.cpp pack_UNSIGNED_*): non-REV types pack the first format component from the
+// most significant bit, *_REV types from the least significant bit.
+
+namespace {
+    namespace ReadbackImpl = MG_Backend::DirectGLES::ReadbackImpl;
+
+    // Converts a row of wide pixels (4 components of wideType each) into `format`/`type` words.
+    template <typename WordT, typename SrcT>
+    Vector<WordT> ConvertWideRowToPackedWords(const Vector<SrcT>& wide, GLenum wideType, GLenum format,
+                                              GLenum type) {
+        ReadbackImpl::ReadbackChannelMapping mapping{};
+        EXPECT_TRUE(ReadbackImpl::GetReadbackChannelMapping(format, mapping));
+        EXPECT_EQ(ReadbackImpl::GetReadbackDstPixelSize(mapping, type), sizeof(WordT));
+        const SizeT width = wide.size() / 4;
+        Vector<WordT> out(width, static_cast<WordT>(0));
+        ReadbackImpl::ConvertWideReadbackRow(reinterpret_cast<const Uint8*>(wide.data()),
+                                             reinterpret_cast<Uint8*>(out.data()), width, wideType, mapping,
+                                             type);
+        return out;
+    }
+
+    // Normalized encodes read the wide row as RGBA8 (values are v / 255).
+    template <typename WordT>
+    Vector<WordT> ConvertRGBA8Row(const Vector<Uint8>& rgba, GLenum format, GLenum type) {
+        return ConvertWideRowToPackedWords<WordT>(rgba, GL_UNSIGNED_BYTE, format, type);
+    }
+
+    // Wide RGBA8 pattern shared by the normalized-encode tests. Expected fields below are
+    // round(v / 255 * (2^bits - 1)), computed by hand per pixel.
+    //                            R     G     B     A
+    const Vector<Uint8> kRGBA8Row{255,  0,    128,  64,     // P0
+                                  10,   250,  33,   200,    // P1
+                                  85,   170,  255,  0};     // P2
+} // namespace
+
+TEST(PackedReadbackEncodeTest, EncodesUnsignedShort565) {
+    // P0: R=31 G=0 B=round(128*31/255)=16      -> 31<<11 | 0<<5 | 16      = 0xF810
+    // P1: R=round(10*31/255)=1 G=round(250*63/255)=62 B=round(33*31/255)=4 -> 1<<11|62<<5|4 = 0x0FC4
+    // P2: R=round(85*31/255)=10 G=round(170*63/255)=42 B=31               -> 10<<11|42<<5|31 = 0x555F
+    const auto words = ConvertRGBA8Row<Uint16>(kRGBA8Row, GL_RGB, GL_UNSIGNED_SHORT_5_6_5);
+    EXPECT_EQ(words[0], 0xF810u);
+    EXPECT_EQ(words[1], 0x0FC4u);
+    EXPECT_EQ(words[2], 0x555Fu);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesUnsignedShort565Rev) {
+    // REV packs R from the LSB: P2 -> 10 | 42<<5 | 31<<11 = 0xFD4A
+    const auto words = ConvertRGBA8Row<Uint16>(kRGBA8Row, GL_RGB, GL_UNSIGNED_SHORT_5_6_5_REV);
+    EXPECT_EQ(words[2], 0xFD4Au);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesUnsignedShort4444) {
+    // P0: R=15 G=0 B=round(128*15/255)=8 A=round(64*15/255)=4 -> 0xF084
+    // P2: R=round(85*15/255)=5 G=round(170*15/255)=10 B=15 A=0 -> 0x5AF0
+    const auto words = ConvertRGBA8Row<Uint16>(kRGBA8Row, GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4);
+    EXPECT_EQ(words[0], 0xF084u);
+    EXPECT_EQ(words[2], 0x5AF0u);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesUnsignedShort4444Rev) {
+    // P0 fields R=15 G=0 B=8 A=4 packed from the LSB -> 15 | 0<<4 | 8<<8 | 4<<12 = 0x480F
+    const auto words = ConvertRGBA8Row<Uint16>(kRGBA8Row, GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4_REV);
+    EXPECT_EQ(words[0], 0x480Fu);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesUnsignedShort5551) {
+    // P0: R=31 G=0 B=16 A=round(64/255)=0  -> 31<<11 | 16<<1        = 0xF820
+    // P1: R=1 G=round(250*31/255)=30 B=4 A=round(200/255)=1 -> 1<<11|30<<6|4<<1|1 = 0x0F89
+    const auto words = ConvertRGBA8Row<Uint16>(kRGBA8Row, GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1);
+    EXPECT_EQ(words[0], 0xF820u);
+    EXPECT_EQ(words[1], 0x0F89u);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesUnsignedShort1555Rev) {
+    // P1 fields R=1 G=30 B=4 A=1 packed from the LSB -> 1 | 30<<5 | 4<<10 | 1<<15 = 0x93C1
+    const auto words = ConvertRGBA8Row<Uint16>(kRGBA8Row, GL_RGBA, GL_UNSIGNED_SHORT_1_5_5_5_REV);
+    EXPECT_EQ(words[1], 0x93C1u);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesUnsignedInt2101010Rev) {
+    // P0: R=1023 G=0 B=round(128*1023/255)=514 A=round(64*3/255)=1 -> 1023|514<<20|1<<30 = 0x602003FF
+    // P2: R=round(85*1023/255)=341 G=round(170*1023/255)=682 B=1023 A=0 -> 0x3FFAA955
+    const auto words = ConvertRGBA8Row<Uint32>(kRGBA8Row, GL_RGBA, GL_UNSIGNED_INT_2_10_10_10_REV);
+    EXPECT_EQ(words[0], 0x602003FFu);
+    EXPECT_EQ(words[2], 0x3FFAA955u);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesUnsignedInt1010102) {
+    // P2 fields R=341 G=682 B=1023 A=0 packed from the MSB -> 341<<22 | 682<<12 | 1023<<2 = 0x556AAFFC
+    const auto words = ConvertRGBA8Row<Uint32>(kRGBA8Row, GL_RGBA, GL_UNSIGNED_INT_10_10_10_2);
+    EXPECT_EQ(words[2], 0x556AAFFCu);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesUnsignedByte332) {
+    // P0: R=7 G=0 B=round(128*3/255)=2                        -> 7<<5 | 2   = 0xE2
+    // P1: R=round(10*7/255)=0 G=round(250*7/255)=7 B=round(33*3/255)=0 -> 7<<2 = 0x1C
+    const auto words = ConvertRGBA8Row<Uint8>(kRGBA8Row, GL_RGB, GL_UNSIGNED_BYTE_3_3_2);
+    EXPECT_EQ(words[0], 0xE2u);
+    EXPECT_EQ(words[1], 0x1Cu);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesUnsignedByte233Rev) {
+    // P0 fields R=7 G=0 B=2 packed from the LSB -> 7 | 0<<3 | 2<<6 = 0x87
+    const auto words = ConvertRGBA8Row<Uint8>(kRGBA8Row, GL_RGB, GL_UNSIGNED_BYTE_2_3_3_REV);
+    EXPECT_EQ(words[0], 0x87u);
+}
+
+TEST(PackedReadbackEncodeTest, Encodes8888KeepsLegacyByteOrder) {
+    // Regression for the previously supported types: P0 = (255, 0, 128, 64).
+    const auto msbFirst = ConvertRGBA8Row<Uint32>(kRGBA8Row, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8);
+    EXPECT_EQ(msbFirst[0], 0xFF008040u);
+    const auto lsbFirst = ConvertRGBA8Row<Uint32>(kRGBA8Row, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV);
+    EXPECT_EQ(lsbFirst[0], 0x408000FFu);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesBGRAWithChannelMapping) {
+    // BGRA's first format component is Blue: P0 fields B=8 G=0 R=15 A=4 -> 8<<12 | 15<<4 | 4 = 0x80F4
+    const auto words = ConvertRGBA8Row<Uint16>(kRGBA8Row, GL_BGRA, GL_UNSIGNED_SHORT_4_4_4_4);
+    EXPECT_EQ(words[0], 0x80F4u);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesIntegerRGBA2101010RevWithFieldClamp) {
+    // Integer sources clamp to each field's unsigned range (10/10/10/2 bits).
+    const Vector<Uint32> wide{1023u, 1024u, 5u, 4u};
+    const auto words =
+        ConvertWideRowToPackedWords<Uint32>(wide, GL_UNSIGNED_INT, GL_RGBA_INTEGER, GL_UNSIGNED_INT_2_10_10_10_REV);
+    EXPECT_EQ(words[0], 0xC05FFFFFu); // 1023 | 1023<<10 | 5<<20 | 3<<30
+}
+
+TEST(PackedReadbackEncodeTest, EncodesIntegerNegativeValuesClampToZero) {
+    const Vector<Int32> wide{-5, 2, 100000, 1};
+    const auto words =
+        ConvertWideRowToPackedWords<Uint32>(wide, GL_INT, GL_RGBA_INTEGER, GL_UNSIGNED_INT_2_10_10_10_REV);
+    EXPECT_EQ(words[0], 0x7FF00800u); // 0 | 2<<10 | 1023<<20 | 1<<30
+}
+
+TEST(PackedReadbackEncodeTest, EncodesIntegerRGB565) {
+    const Vector<Uint32> wide{31u, 64u, 2u, 0u};
+    const auto words =
+        ConvertWideRowToPackedWords<Uint16>(wide, GL_UNSIGNED_INT, GL_RGB_INTEGER, GL_UNSIGNED_SHORT_5_6_5);
+    EXPECT_EQ(words[0], 0xFFE2u); // 31<<11 | 63<<5 | 2 (G clamps 64 -> 63)
+}
+
+TEST(PackedReadbackEncodeTest, EncodesPackedFloat10F11F11FRev) {
+    // F11(1.0)=0x3C0 F11(0.5)=0x380 F10(0.25)=0x1A0 -> 0x3C0 | 0x380<<11 | 0x1A0<<22 = 0x681C03C0.
+    // Second pixel: values above 65024 clamp to the max finite F11 (0x7BF), negatives go to zero.
+    const Vector<Float> wide{1.0f, 0.5f, 0.25f, 1.0f, 100000.0f, -1.0f, 0.25f, 1.0f};
+    const auto words = ConvertWideRowToPackedWords<Uint32>(wide, GL_FLOAT, GL_RGB, GL_UNSIGNED_INT_10F_11F_11F_REV);
+    EXPECT_EQ(words[0], 0x681C03C0u);
+    EXPECT_EQ(words[1], 0x680007BFu);
+}
+
+TEST(PackedReadbackEncodeTest, EncodesSharedExponent5999Rev) {
+    // (1.0, 0.5, 0.25): shared exponent 16, fields 256/128/64 -> 256 | 128<<9 | 64<<18 | 16<<27
+    const Vector<Float> wide{1.0f, 0.5f, 0.25f, 1.0f};
+    const auto words = ConvertWideRowToPackedWords<Uint32>(wide, GL_FLOAT, GL_RGB, GL_UNSIGNED_INT_5_9_9_9_REV);
+    EXPECT_EQ(words[0], 0x81010100u);
+}
+
+TEST(PackedReadbackEncodeTest, RejectsMismatchedPackedFieldCounts) {
+    ReadbackImpl::ReadbackChannelMapping rgba{};
+    ASSERT_TRUE(ReadbackImpl::GetReadbackChannelMapping(GL_RGBA, rgba));
+    ReadbackImpl::ReadbackChannelMapping rgbInteger{};
+    ASSERT_TRUE(ReadbackImpl::GetReadbackChannelMapping(GL_RGB_INTEGER, rgbInteger));
+
+    // 3-field packed types never pair with 4-component formats and vice versa.
+    EXPECT_EQ(ReadbackImpl::GetReadbackDstPixelSize(rgba, GL_UNSIGNED_SHORT_5_6_5), 0u);
+    EXPECT_EQ(ReadbackImpl::GetReadbackDstPixelSize(rgbInteger, GL_UNSIGNED_SHORT_4_4_4_4), 0u);
+    // Packed-float RGB types never pair with integer formats.
+    EXPECT_EQ(ReadbackImpl::GetReadbackDstPixelSize(rgbInteger, GL_UNSIGNED_INT_5_9_9_9_REV), 0u);
+    EXPECT_EQ(ReadbackImpl::GetReadbackDstPixelSize(rgbInteger, GL_UNSIGNED_INT_10F_11F_11F_REV), 0u);
+}
+
+// ---- GL CTS packed_pixels readback root-cause regressions --------------------------------------
+
+TEST_F(FramebufferTest, ReadPixelsRejectsIntegerFormatMismatchWithReadBuffer) {
+    GLuint framebuffer = 0;
+    GLuint texture = 0;
+    MG_Impl::GLImpl::CreateFramebuffers(1, &framebuffer);
+    MG_Impl::GLImpl::CreateTextures(GL_TEXTURE_2D, 1, &texture);
+    MG_Impl::GLImpl::TextureStorage2D(texture, 1, GL_RGBA8UI, 4, 4);
+    MG_Impl::GLImpl::NamedFramebufferTexture(framebuffer, GL_COLOR_ATTACHMENT0, texture, 0);
+    MG_Impl::GLImpl::BindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
+
+    MG_Backend::gBackendFunctionsTable.GL.ReadPixels = RecordReadPixels;
+    Uint8 pixelStorage[4 * 4 * 4] = {};
+
+    // GL 3.3 section 4.3.1: normalized format on an integer read buffer -> GL_INVALID_OPERATION
+    // (GL CTS packed_pixels expects the error for every mismatched combination).
+    MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, GL_RGBA, GL_UNSIGNED_BYTE, pixelStorage);
+    EXPECT_EQ(g_readPixelsCallCount, 0);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_INVALID_OPERATION);
+
+    // The matching integer readback stays valid.
+    MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, GL_RGBA_INTEGER, GL_UNSIGNED_INT, pixelStorage);
+    EXPECT_EQ(g_readPixelsCallCount, 1);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    // And the inverse mismatch: integer format on a normalized attachment.
+    GLuint normalizedTexture = 0;
+    MG_Impl::GLImpl::CreateTextures(GL_TEXTURE_2D, 1, &normalizedTexture);
+    MG_Impl::GLImpl::TextureStorage2D(normalizedTexture, 1, GL_RGBA8, 4, 4);
+    MG_Impl::GLImpl::NamedFramebufferTexture(framebuffer, GL_COLOR_ATTACHMENT0, normalizedTexture, 0);
+    MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, GL_RGBA_INTEGER, GL_UNSIGNED_INT, pixelStorage);
+    EXPECT_EQ(g_readPixelsCallCount, 1);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_INVALID_OPERATION);
+}
+
+TEST_F(FramebufferTest, BindRenderbufferZeroUnbindsWithoutError) {
+    // The GL CTS state reset calls glBindRenderbuffer(GL_RENDERBUFFER, 0) and expects no error;
+    // name 0 used to be reported as an invalid renderbuffer name.
+    MG_Impl::GLImpl::BindRenderbuffer(GL_RENDERBUFFER, 0);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+}
+
+TEST_F(FramebufferTest, FramebufferTexture3DAttachesSliceWithLayerTracking) {
+    // glFramebufferTexture3D with zoffset used to be rejected outright, leaving a sticky
+    // GL_INVALID_OPERATION behind (GL CTS packed_pixels varied_rectangle runs on GL_TEXTURE_3D).
+    GLuint framebuffer = 0;
+    GLuint texture = 0;
+    MG_Impl::GLImpl::CreateFramebuffers(1, &framebuffer);
+    MG_Impl::GLImpl::CreateTextures(GL_TEXTURE_3D, 1, &texture);
+    MG_Impl::GLImpl::TextureStorage3D(texture, 1, GL_RGBA8, 4, 4, 2);
+
+    MG_Impl::GLImpl::BindFramebuffer(GL_DRAW_FRAMEBUFFER, framebuffer);
+    MG_Impl::GLImpl::FramebufferTexture3D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_3D, texture, 0, 1);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+
+    const auto framebufferObject = MG_State::pGLContext->GetFramebufferObject(framebuffer);
+    ASSERT_NE(framebufferObject, nullptr);
+    const auto& attachment = framebufferObject->GetAttachment(FramebufferAttachmentType::Color0);
+    ASSERT_TRUE(attachment.IsTexture());
+    EXPECT_EQ(attachment.GetTextureLayer(), 1);
+    EXPECT_FALSE(attachment.IsLayered());
+}
+
+TEST_F(FramebufferTest, NonRenderableColorFormatsReportUnsupportedFramebuffer) {
+    // Without a probing backend the conservative list applies: RGB9_E5 is texture-only, so
+    // attaching it must not report GL_FRAMEBUFFER_COMPLETE (GL CTS packed_pixels rgb9_e5 expects
+    // read errors instead of silent unwritten readbacks).
+    GLuint framebuffer = 0;
+    GLuint texture = 0;
+    MG_Impl::GLImpl::CreateFramebuffers(1, &framebuffer);
+    MG_Impl::GLImpl::CreateTextures(GL_TEXTURE_2D, 1, &texture);
+    MG_Impl::GLImpl::TextureStorage2D(texture, 1, GL_RGB9_E5, 4, 4);
+    MG_Impl::GLImpl::NamedFramebufferTexture(framebuffer, GL_COLOR_ATTACHMENT0, texture, 0);
+    MG_Impl::GLImpl::BindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
+
+    EXPECT_EQ(MG_Impl::GLImpl::CheckFramebufferStatus(GL_READ_FRAMEBUFFER),
+              static_cast<GLenum>(GL_FRAMEBUFFER_UNSUPPORTED));
+
+    Uint8 pixelStorage[4 * 4 * 4] = {};
+    MG_Impl::GLImpl::ReadPixels(0, 0, 4, 4, GL_RGBA, GL_UNSIGNED_BYTE, pixelStorage);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_INVALID_FRAMEBUFFER_OPERATION);
+}

MobileGL/MG_Test/Pipeline/CMakeLists.txt

@@ -0,0 +1,27 @@
+cmake_minimum_required(VERSION 3.14)
+
+add_executable(
+        PipelineQuirkTest
+        PipelineQuirkTest.cpp
+)
+
+target_include_directories(PipelineQuirkTest PRIVATE
+        ${MGL_ROOT}/include
+        ${MGL_ROOT}/MobileGL
+        ${MGL_ROOT}/3rdparty/xxHash
+        ${MGL_ROOT}/3rdparty/Vulkan-Headers/include
+        ${MGL_ROOT}/3rdparty/SPIRV-Reflect
+)
+
+target_link_libraries(
+        PipelineQuirkTest PRIVATE
+        GTest::gtest_main
+        ${LINK_LIBRARIES}
+)
+
+if (MSVC)
+        target_compile_options(PipelineQuirkTest PRIVATE /Zc:preprocessor)
+endif()
+
+include(GoogleTest)
+gtest_discover_tests(PipelineQuirkTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)