[Fix] (DirectGLES): repair the emulation-guard mask restore and scissor the resolve fallback's staging blit correctly

Final audit round over the DirectGLES scratch/shadow mechanisms; three verified
defects fixed:

- ~ScopedEmulationDrawState restored the APPLICATION's per-buffer colour masks,
  not what SyncRenderState actually pushed: a widened attachment's alpha-off
  doctoring (g_syncedColorMaskAlphaWidenMask) was dropped while the memo still
  claimed it applied, so the next sync early-outed and draws wrote fragment
  alpha into the widened buffer - breaking the stored-alpha==1.0 invariant the
  widen discipline exists to protect. The restore now re-applies the doctoring.
- The same restore loop gated on the core glColorMaski name only, while the sync
  push falls back to glColorMaskiEXT/OES: EXT/OES-only devices were left holding
  buffer 0's mask broadcast across every draw buffer with the shadow recording
  the divergent set (never repaired). The restore now uses the same three-way
  pointer fallback.
- ResolveThenBlit ran its resolve-into-scratch staging blit under the
  application's scissor: a box not covering the scratch-origin rect clipped the
  resolve silently (no GL error), and the second blit then copied stale scratch
  renderbuffer texels into the destination. The staging blit now runs scissor-off
  (shadow-tracked, like ScopedScissorDisable); the caller-visible blit keeps its
  native scissor semantics.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MsqQQF7ugn7MqZXcmnmz1z

MobileGL/Init.cpp

@@ -15,6 +15,7 @@
 #include <MG_Impl/GLImpl/Texture/ProxyTexture.h>
 #include <MG_Impl/GLImpl/Framebuffer/GL_Framebuffer.h>
 #include <MG_Impl/GLImpl/Sync/GL_Sync.h>
+#include <MG_Impl/GLImpl/Query/GL_Query.h>
 #include <MG_Util/Async/ShaderCompilePool.h>
 #include <MG_Util/ShaderTranspiler/ShaderCompiler.h>
 
@@ -51,6 +52,11 @@ namespace MobileGL {
             // before a re-initialized library could pair them with the wrong
             // backend's DeleteSync).
             MG_Impl::GLImpl::DestroyAllSyncObjects();
+            // Queries die with their contexts for the same reason, and their registry
+            // is the same shape of process-global map: drain it here too, while the
+            // function table can still pair each backend handle with the backend that
+            // minted it.
+            MG_Impl::GLImpl::DestroyAllQueryObjects();
             MG_Backend::pActiveBackendObject.reset();
             MG_State::pGLContext.reset();
             MG_State::pEGLContext.reset();

MobileGL/MG_Backend/DirectGLES/DirectGLES.cpp

@@ -1431,6 +1431,7 @@ namespace MobileGL::MG_Backend::DirectGLES {
             g_fboSyncedSlotVersions[SizeT(target)] = slotVersion;
             g_fboSyncedObjectVersions[SizeT(target)] = objectVersion;
             g_fboSyncedObjects[SizeT(target)] = fbo;
+            g_fboSyncedBackendIdGenerations[SizeT(target)] = g_attachmentBackendIdGeneration;
         }
 
         void SyncCurrentFBO() {
@@ -1461,9 +1462,13 @@ namespace MobileGL::MG_Backend::DirectGLES {
                 const Uint16 slotVersion = slot.GetVersion();
                 const Uint16 objectVersion = currentFBO ? currentFBO->GetObjectVersion() : 0;
                 auto* currentPtr = currentFBO.get();
+                // The backend-id generation joins the triple: a backend texture re-mint
+                // (RecreateBackendTexture) moves no frontend version, so without it the
+                // early-out would keep the driver FBO on the deleted texture name.
                 if (slotVersion == g_fboSyncedSlotVersions[SizeT(target)] &&
                     objectVersion == g_fboSyncedObjectVersions[SizeT(target)] &&
-                    currentPtr == g_fboSyncedObjects[SizeT(target)]) {
+                    currentPtr == g_fboSyncedObjects[SizeT(target)] &&
+                    g_fboSyncedBackendIdGenerations[SizeT(target)] == g_attachmentBackendIdGeneration) {
                     lastUpdatedFBO = currentPtr;
                     continue;
                 }
@@ -2129,6 +2134,15 @@ namespace MobileGL::MG_Backend::DirectGLES {
         static Bool g_broadcastMemoValid = false;
         static Uint g_broadcastMemoCount = 1;
 
+        // The identity+version key above is only monotonic WITHIN one GLContext: a
+        // library teardown + re-init frees every FramebufferObject and restarts the
+        // draw slot's counter at zero, so a recycled FBO address with coinciding
+        // fresh versions would false-hit. Cleared at the same boundaries as the
+        // structurally identical SyncCurrentFBO trio (InvalidateFramebufferBindingCache).
+        void InvalidateBroadcastMemo() {
+            g_broadcastMemoValid = false;
+        }
+
         void SyncCurrentProgram(const SharedPtr<MG_State::GLState::ProgramObject>& currentProgram) {
 #ifdef TRACY_ENABLE
             ZoneScopedC(TRACY_ZONECOLOR_BACKEND);
@@ -2312,6 +2326,8 @@ namespace MobileGL::MG_Backend::DirectGLES {
         FramebufferImpl::g_fboSyncedSlotVersions[(SizeT)target] = slot.GetVersion();
         FramebufferImpl::g_fboSyncedObjectVersions[(SizeT)target] = fbo ? fbo->GetObjectVersion() : 0;
         FramebufferImpl::g_fboSyncedObjects[(SizeT)target] = fbo.get();
+        FramebufferImpl::g_fboSyncedBackendIdGenerations[(SizeT)target] =
+            FramebufferImpl::g_attachmentBackendIdGeneration;
     }
 
     static void BindCurrentProgramWithResources(
@@ -3950,8 +3966,19 @@ namespace MobileGL::MG_Backend::DirectGLES {
         Bool resolved = g_GLESFuncs.glCheckFramebufferStatus(GL_DRAW_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE;
         if (resolved) {
             DrainBlitErrors();
+            // A blit is scissored like a draw (the replicate path's guard documents the
+            // same rule): the application's box would clip this resolve into the
+            // scratch, and the second blit would then copy never-written scratch texels
+            // into the destination - silently, since scissor clipping raises no GL
+            // error. Disable for the staging blit only; the caller-visible blit below
+            // keeps the blit's native scissor semantics. Tracked via the render-state
+            // shadow, exactly like ScopedScissorDisable.
+            const Bool scissorWasEnabled =
+                (RenderStateImpl::g_syncedRenderStateParameters.ScissorTestEnabledMask & 1u) != 0;
+            if (scissorWasEnabled) g_GLESFuncs.glDisable(GL_SCISSOR_TEST);
             g_GLESFuncs.glBlitFramebuffer(left, bottom, right, top, 0, 0, width, height, GL_COLOR_BUFFER_BIT,
                                           GL_NEAREST);
+            if (scissorWasEnabled) g_GLESFuncs.glEnable(GL_SCISSOR_TEST);
             resolved = g_GLESFuncs.glGetError() == GL_NO_ERROR;
         }
         if (resolved) {
@@ -4097,13 +4124,25 @@ namespace MobileGL::MG_Backend::DirectGLES {
                 }
             }
             // The per-draw-buffer colour masks are not covered by the non-indexed
-            // glColorMask above.
-            for (Uint index = 0; index < MG_State::GLState::FramebufferObject::MAX_DRAW_BUFFERS; ++index) {
-                const BoolVec4& colorMask = RenderStateImpl::g_syncedRenderStateParameters.ColorMasks[index];
-                if (g_GLESFuncs.glColorMaski) {
-                    g_GLESFuncs.glColorMaski(index, colorMask.x() ? GL_TRUE : GL_FALSE,
-                                             colorMask.y() ? GL_TRUE : GL_FALSE, colorMask.z() ? GL_TRUE : GL_FALSE,
-                                             colorMask.w() ? GL_TRUE : GL_FALSE);
+            // glColorMask above. Restore what the SYNC actually pushed, not the raw
+            // application masks: a widened attachment's alpha write is forced off by
+            // SyncRenderState and memoized in g_syncedColorMaskAlphaWidenMask, and the
+            // next sync early-outs on an unchanged version - restoring the undoctored
+            // mask here would leave alpha writes enabled on the widened buffer with
+            // nothing left to repair it. Same three-way pointer fallback as
+            // SyncRenderState's push: gating on the core name alone left EXT/OES-only
+            // devices holding buffer 0's mask broadcast across every buffer.
+            const auto colorMaskiFn = g_GLESFuncs.glColorMaski      ? g_GLESFuncs.glColorMaski
+                                      : g_GLESFuncs.glColorMaskiEXT ? g_GLESFuncs.glColorMaskiEXT
+                                                                    : g_GLESFuncs.glColorMaskiOES;
+            if (colorMaskiFn) {
+                for (Uint index = 0; index < MG_State::GLState::FramebufferObject::MAX_DRAW_BUFFERS; ++index) {
+                    BoolVec4 colorMask = RenderStateImpl::g_syncedRenderStateParameters.ColorMasks[index];
+                    if (index < 32 && (RenderStateImpl::g_syncedColorMaskAlphaWidenMask & (1u << index)) != 0) {
+                        colorMask.w() = false;
+                    }
+                    colorMaskiFn(index, colorMask.x() ? GL_TRUE : GL_FALSE, colorMask.y() ? GL_TRUE : GL_FALSE,
+                                 colorMask.z() ? GL_TRUE : GL_FALSE, colorMask.w() ? GL_TRUE : GL_FALSE);
                 }
             }
             if (m_pausedTransformFeedback && g_GLESFuncs.glResumeTransformFeedback) {
@@ -8304,6 +8343,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // Conservatively drop the redundant-glUseProgram guard: re-issuing one bind
         // after a MakeCurrent is cheaper than trusting a possibly-reset context.
         PrgramImpl::g_lastUsedBackendProgramId = 0;
+        // The GLContext becoming current may be a fresh one whose slot versions
+        // restarted at zero; the broadcast memo's key is only monotonic within one.
+        PrgramImpl::InvalidateBroadcastMemo();
         BufferImpl::InvalidateIndexedBufferBindingCache();
         BufferImpl::InvalidatePixelBufferBindingCaches();
         FramebufferImpl::InvalidateFramebufferBindingCache();
@@ -8832,6 +8874,7 @@ namespace MobileGL::MG_Backend::DirectGLES {
         FramebufferImpl::InvalidateFramebufferBindingCache();
         VertexArrayImpl::InvalidateVAOBindingCache();
         PixelStoreImpl::InvalidatePackStateCache();
+        PrgramImpl::InvalidateBroadcastMemo();
         // Texture ids belong to the dying context; wrappers destroyed later must
         // not glDeleteTextures a recycled name in a successor context.
         ++g_backendContextGeneration;

MobileGL/MG_Backend/DirectGLES/Managers.cpp

@@ -577,6 +577,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
                 // immutable storage, and any prior mutable store is replaced anyway.
                 if (resource->id != 0) {
                     NoteBufferIdDeleted(resource->id);
+                    // Driver VAOs may have this id baked into attribute/element bindings
+                    // keyed on frontend versions this re-mint does not move.
+                    ++g_bufferBackendIdGeneration;
                     g_GLESFuncs.glDeleteBuffers(1, &resource->id);
                     resource->id = 0;
                     resource->immutableStorage = false;
@@ -833,6 +836,10 @@ namespace MobileGL::MG_Backend::DirectGLES {
             g_bufferMutationEpoch.fetch_add(1, std::memory_order_release);
         }
 
+        // See the declaration: re-mints of a live resource's driver id. Written only on
+        // the context thread (both re-mint sites run there), read only by the VAO sync.
+        Uint64 g_bufferBackendIdGeneration = 0;
+
         void RegisterBufferBackendOps() {
             MG_State::GLState::SetBufferBackendOps(&g_glesBufferBackendOps);
             // Frontend writes issued while ops were unregistered advanced change
@@ -960,6 +967,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // here, on the thread that can, and the id is re-minted below.
             if (resource->immutableStorage && !resource->persistentMapped && resource->id != 0) {
                 NoteBufferIdDeleted(resource->id);
+                // Same as the persistent-map re-mint: the dying id may be baked into
+                // driver VAO bindings whose frontend versions do not move for this.
+                ++g_bufferBackendIdGeneration;
                 g_GLESFuncs.glDeleteBuffers(1, &resource->id);
                 resource->id = 0;
                 resource->immutableStorage = false;
@@ -1640,8 +1650,24 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // PrepareForDraw's BindCurrentVAO establishes the draw binding regardless.
             const Uint32 currentConfigVersion = stateVAOObject->GetConfigVersion();
             const Uint16 currentIndexBufferVersion = stateVAOObject->GetIndexBufferBindingSlot().GetVersion();
-            const Bool attributesDirty = !m_hasSyncedConfigVersion || m_syncedConfigVersion != currentConfigVersion;
-            const Bool indexBufferDirty = currentIndexBufferVersion != m_syncedIndexBufferVersion;
+            // A live buffer's driver id was re-minted since this twin's last emit
+            // (persistent-map adoption / immutable-store retire): every baked binding may
+            // hold the dead id while every frontend version still matches, so force a
+            // full re-emit. Read once; each buffer re-mints at most once per walk (its
+            // first EnsureBufferResource this draw), before its id is baked, so stamping
+            // the entry value at the end is exact - and a stale stamp only costs one
+            // extra full emit.
+            const Uint64 currentBufferIdGeneration = BufferImpl::g_bufferBackendIdGeneration;
+            const Bool bufferIdsRemitted = m_syncedBufferIdGeneration != currentBufferIdGeneration;
+            const Bool attributesDirty =
+                bufferIdsRemitted || !m_hasSyncedConfigVersion || m_syncedConfigVersion != currentConfigVersion;
+            // Identity joins the version compare: the slot version is a wrapping Uint16,
+            // so a wrapped-back count with a different buffer bound must still read dirty.
+            const MG_State::GLState::BufferObject* currentIndexBufferObject =
+                stateVAOObject->GetIndexBufferBindingSlot().GetBoundObject().get();
+            const Bool indexBufferDirty = bufferIdsRemitted ||
+                                          currentIndexBufferVersion != m_syncedIndexBufferVersion ||
+                                          currentIndexBufferObject != m_syncedIndexBufferObject;
 
             // The baseInstance shift lives in the attribute offsets the driver already holds, so
             // a change of baseInstance has to re-emit the divisor'd arrays even when the frontend
@@ -1675,10 +1701,10 @@ namespace MobileGL::MG_Backend::DirectGLES {
                     }
                 }
 
-                Bool needsSyncFormat = allAttributeVersions[attribIndex].FormatVersion !=
-                                       m_syncedAttributeVersions[attribIndex].FormatVersion;
-                Bool needsSyncBuffer = allAttributeVersions[attribIndex].BufferVersion !=
-                                       m_syncedAttributeVersions[attribIndex].BufferVersion;
+                Bool needsSyncFormat = bufferIdsRemitted || allAttributeVersions[attribIndex].FormatVersion !=
+                                                               m_syncedAttributeVersions[attribIndex].FormatVersion;
+                Bool needsSyncBuffer = bufferIdsRemitted || allAttributeVersions[attribIndex].BufferVersion !=
+                                                               m_syncedAttributeVersions[attribIndex].BufferVersion;
                 if (!needsSyncFormat && !needsSyncBuffer && !needsSyncBaseInstance) continue;
 
                 // Defence in depth. The frontend already declines glVertexAttribLFormat on this
@@ -1798,6 +1824,7 @@ namespace MobileGL::MG_Backend::DirectGLES {
 
                 if (indexBufferSynced) {
                     m_syncedIndexBufferVersion = currentIndexBufferVersion;
+                    m_syncedIndexBufferObject = currentIndexBufferObject;
                 }
             }
 
@@ -1809,6 +1836,7 @@ namespace MobileGL::MG_Backend::DirectGLES {
             if (emitAttributes) {
                 m_syncedFetchBaseInstance = fetchBaseInstance;
             }
+            m_syncedBufferIdGeneration = currentBufferIdGeneration;
         }
 
         void BackendVertexArrayObject::SyncClientSideAttributesForDrawArrays(
@@ -1946,6 +1974,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
         void BackendTextureObject::RecreateBackendTexture() {
             if (m_backendTextureId != 0) {
                 ScratchFBOImpl::NoteTextureIdDeleted(m_backendTextureId);
+                // Application FBO twins that attached the dying id memoize on FRONTEND
+                // attachment versions, which this backend-side re-mint does not move;
+                // without this bump their driver FBOs would keep the deleted name
+                // attached forever (see g_attachmentBackendIdGeneration).
+                ++FramebufferImpl::g_attachmentBackendIdGeneration;
                 if (m_contextGeneration == g_backendContextGeneration) {
                     g_GLESFuncs.glDeleteTextures(1, &m_backendTextureId);
                 }
@@ -3517,6 +3550,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
             m_backendReadBuffer = GL_NONE;
             std::fill(m_syncedFrontendAttachmentVersions.begin(), m_syncedFrontendAttachmentVersions.end(),
                       static_cast<Uint16>(~0u));
+            // Every attachment version is invalidated above, so the next walk re-attaches
+            // everything regardless; stamp the generation so it does not re-arm twice.
+            m_syncedBackendIdGeneration = g_attachmentBackendIdGeneration;
         }
 
         static Bool SyncAttachmentObject(GLenum glFBOTarget,
@@ -4005,6 +4041,15 @@ namespace MobileGL::MG_Backend::DirectGLES {
             }
 
             // -------------------- Attach texture to backend FBO -----------------------
+            // A backend texture id was re-minted since this twin's last walk
+            // (RecreateBackendTexture): any point here may still hold the dead id while
+            // its frontend attachment version is unchanged, so the memo below would skip
+            // exactly the attachment that needs repair. Re-arm every point first.
+            if (m_syncedBackendIdGeneration != g_attachmentBackendIdGeneration) {
+                std::fill(m_syncedFrontendAttachmentVersions.begin(), m_syncedFrontendAttachmentVersions.end(),
+                          static_cast<Uint16>(~0u));
+                m_syncedBackendIdGeneration = g_attachmentBackendIdGeneration;
+            }
             const auto& attachments = stateFBOObject->GetAllAttachmentObjects();
             const auto& attachmentVersions = stateFBOObject->GetAllFramebufferAttachmentVersions();
             for (SizeT i = 0; i < attachments.size(); ++i) {
@@ -4093,6 +4138,18 @@ namespace MobileGL::MG_Backend::DirectGLES {
                 }
 #endif
             }
+
+            // The walk itself can re-mint an id (SyncAttachmentObject ->
+            // SyncMipmapsToBackend -> RecreateBackendTexture), invalidating points this
+            // walk already attached or version-skipped - e.g. one texture attached at two
+            // points. Re-enter until the generation is quiescent: every pass syncs each
+            // dirty texture clean, so each repeat finds strictly fewer re-mints and the
+            // common case (no re-mint) never takes a second pass. The head's draw/read-
+            // buffer syncs are memoized against their own shadows, so a repeat re-walks
+            // only the attachments.
+            if (m_syncedBackendIdGeneration != g_attachmentBackendIdGeneration) {
+                SyncToBackend(stateFBOObject, asTarget);
+            }
         }
 
         GLenum BackendFramebufferObject::GetBackendAttachmentType(FramebufferAttachmentType frontendAtt) const {
@@ -4119,6 +4176,8 @@ namespace MobileGL::MG_Backend::DirectGLES {
         Array<Uint16, SizeT(FramebufferTarget::FramebufferTargetCount)> g_fboSyncedObjectVersions = {0};
         Array<MG_State::GLState::FramebufferObject*, SizeT(FramebufferTarget::FramebufferTargetCount)>
             g_fboSyncedObjects = {};
+        Uint64 g_attachmentBackendIdGeneration = 0;
+        Array<Uint64, SizeT(FramebufferTarget::FramebufferTargetCount)> g_fboSyncedBackendIdGenerations = {0};
     } // namespace FramebufferImpl
 
     namespace ScratchFBOImpl {

MobileGL/MG_Backend/DirectGLES/Managers.h

@@ -346,6 +346,14 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // client-attribute staging buffers): scrub every buffer-binding shadow that
         // could false-skip when the name is recycled.
         void NoteBufferIdDeleted(Uint id);
+        // Bumped whenever a live GLESBufferResource's driver id is retired and re-minted
+        // while its frontend buffer stays alive (persistent-map adoption, immutable-store
+        // retire). The VAO twins' baked glVertexAttribPointer / element-array bindings
+        // key on FRONTEND versions, which a backend-side re-mint does not move - without
+        // this generation the driver VAO would keep fetching through the deleted id (or
+        // its retained store) forever. Compared and stamped by
+        // BackendVertexArrayObject::SyncToBackend.
+        extern Uint64 g_bufferBackendIdGeneration;
         // Redundant-bind cache for INDEXED buffer bindings (glBindBufferBase/Range on
         // GL_UNIFORM_BUFFER / GL_SHADER_STORAGE_BUFFER): skips the GL call when the
         // (id, range) already at that index matches, like the array-buffer/texture/
@@ -465,6 +473,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
             Array<Uint, MG_State::GLState::VertexArrayObject::MAX_VERTEX_ATTRIBS> m_clientAttributeBufferIds;
             Bool m_isInitialized = false;
             Uint16 m_syncedIndexBufferVersion = 0;
+            // Identity of the buffer the version above was stamped against. Raw and never
+            // dereferenced: the slot version is a wrapping Uint16 (see the ResolvedDrawBuffers
+            // IBO memo and the packed_pixels postmortem at BindCurrentFBO), so the version
+            // alone would read a wrapped-back count with a different buffer bound as clean.
+            const MG_State::GLState::BufferObject* m_syncedIndexBufferObject = nullptr;
             // Aggregate gate over the per-attribute walk below: the frontend bumps its config
             // version on every per-attribute version bump (the three Bump*Version functions are
             // its only writers), so an unchanged config version proves every per-attribute
@@ -480,6 +493,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // Kept here because it describes what was last EMITTED, which is what the next sync
             // has to correct.
             Uint32 m_syncedFetchBaseInstance = 0;
+            // BufferImpl::g_bufferBackendIdGeneration as of this twin's last emit. A
+            // mismatch means some live buffer's driver id was re-minted since; the ids
+            // baked into the driver VAO's attribute/element bindings may be dead even
+            // though every frontend version matches, so the next sync re-emits them all.
+            Uint64 m_syncedBufferIdGeneration = 0;
         };
 
         extern StateBackendObjectRegistry<MG_State::GLState::VertexArrayObject, BackendVertexArrayObject>
@@ -799,6 +817,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
 
             using FramebufferObject = MG_State::GLState::FramebufferObject;
             FramebufferObject::FramebufferAttachmentVersionArray m_syncedFrontendAttachmentVersions = {0};
+            // g_attachmentBackendIdGeneration as of this twin's last attachment walk. A
+            // mismatch means some backend texture id was re-minted since, and any of this
+            // twin's attachment points may still hold the dead id even though the frontend
+            // attachment versions match - so the walk re-attaches everything first.
+            Uint64 m_syncedBackendIdGeneration = 0;
         };
 
         extern StateBackendObjectRegistry<MG_State::GLState::FramebufferObject, BackendFramebufferObject>
@@ -888,6 +911,19 @@ namespace MobileGL::MG_Backend::DirectGLES {
         extern Array<MG_State::GLState::FramebufferObject*, SizeT(FramebufferTarget::FramebufferTargetCount)>
             g_fboSyncedObjects;
 
+        // Bumped whenever a live backend texture's driver id is re-minted while its
+        // frontend texture may still be attached to application FBOs
+        // (BackendTextureObject::RecreateBackendTexture - e.g. a respecify of a texture
+        // whose backend storage went immutable). The FBO twins' attachment memos key on
+        // FRONTEND attachment versions, which a backend-side re-mint does not move, so
+        // the driver FBO would keep the deleted texture name attached forever. The
+        // SyncCurrentFBO gate compares this generation (below) to re-enter the sync,
+        // and each twin re-arms its per-attachment memo on a mismatch (SyncToBackend).
+        extern Uint64 g_attachmentBackendIdGeneration;
+        // What g_attachmentBackendIdGeneration was when SyncCurrentFBO last stamped each
+        // target; part of the synced tuple above.
+        extern Array<Uint64, SizeT(FramebufferTarget::FramebufferTargetCount)> g_fboSyncedBackendIdGenerations;
+
         // Driver-level READ/DRAW framebuffer-binding shadow. Every backend
         // glBindFramebuffer routes through BindFramebufferId so scoped helpers can
         // save/restore the current binding without a glGetIntegerv round-trip (that

MobileGL/MG_Backend/DirectVulkan/DirectVulkan.cpp

@@ -69,6 +69,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // slot's ownership unambiguous.
             Uint64 programLifetimeId = 0;
             Uint32 backendStateVersion = 0;
+            // glShaderStorageBlockBinding deliberately does NOT bump the backend state
+            // version, and the pipeline composite is unnamed so the in-place patch in
+            // DirectVulkan::ShaderStorageBlockBinding can never reach its slot - the
+            // mirror replay bumps only the program's block-binding version. Without this
+            // key the composite's slot kept serving the pre-rebind block.binding.
+            Uint32 blockBindingVersion = 0;
             Vector<StorageBlockResource> storageBlocks;
             Vector<BufferVariableResource> bufferVariables;
             GLint computeWorkGroupSize[3] = {1, 1, 1};
@@ -156,18 +162,33 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             auto& cache = g_programResourceCaches[program.GetExternalIndex()];
             const Uint64 programLifetimeId = program.GetLifetimeId();
             const Uint32 backendStateVersion = program.GetBackendStateVersion();
+            const Uint32 blockBindingVersion = program.GetBlockBindingVersion();
             // The lifetime id must match too: a new program that reuses a deleted
             // program's name and happens to land on the same backendStateVersion (both
             // count from zero) would otherwise be served the dead program's reflection.
             if (cache.programLifetimeId == programLifetimeId &&
                 cache.backendStateVersion == backendStateVersion &&
                 (!cache.storageBlocks.empty() || !cache.bufferVariables.empty())) {
+                if (cache.blockBindingVersion != blockBindingVersion) {
+                    // Only the block bindings moved (glShaderStorageBlockBinding, or the
+                    // pipeline composite's mirror replay - neither touches the backend
+                    // state version): the reflection itself is unchanged, so re-apply the
+                    // overrides by name instead of re-running spirv-reflect. Overrides
+                    // only ever accumulate, so a block without one still holds its
+                    // declared binding.
+                    for (auto& block : cache.storageBlocks) {
+                        const Int rebound = program.GetShaderStorageBlockBindingOverride(block.name);
+                        if (rebound >= 0) block.binding = static_cast<Uint32>(rebound);
+                    }
+                    cache.blockBindingVersion = blockBindingVersion;
+                }
                 return cache;
             }
 
             cache = {};
             cache.programLifetimeId = programLifetimeId;
             cache.backendStateVersion = backendStateVersion;
+            cache.blockBindingVersion = blockBindingVersion;
 
             Vector<SpvReflectShaderModule> modules;
             Vector<Bool> validModules;

MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.cpp

@@ -287,8 +287,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             if (m_frameBoundaryCounter - it->second->lastUsedFrameBoundary > kRetireAgeBoundaries) {
                 it = m_cache.erase(it);
                 // Invalidate every VAO's state-pointer memo: the erased node's
-                // address may be reused by a future insert.
-                ++m_evictionEpoch;
+                // address may be reused by a future insert. Advance through the
+                // process-wide source so the value stays unique across factory
+                // instances (see the member comment).
+                m_evictionEpoch = ++s_evictionEpochSource;
             } else {
                 ++it;
             }

MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.h

@@ -125,7 +125,17 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // construction); a memo is honored only while its recorded epoch
         // matches, so an evicted entry can never be dereferenced through a
         // stale memo.
-        Uint64 m_evictionEpoch = 1;
+        //
+        // Drawn from a process-wide source, never a per-instance counter: the VAO
+        // memos outlive this factory (they live on pGLContext's VAOs, the renderer
+        // is destroyed and recreated on EGL surface release/re-create), so a fresh
+        // factory restarting at a dead factory's epoch value would honor its
+        // dangling entry pointers. The constructor takes a value strictly greater
+        // than anything a predecessor ever stamped, so a dead factory's memo can
+        // never compare equal here - the same never-reused idiom as the lifetime ids.
+        // Single-threaded like the rest of the factory (renderer-thread only).
+        static inline Uint64 s_evictionEpochSource = 0;
+        Uint64 m_evictionEpoch = ++s_evictionEpochSource;
         static inline XXH64_state_t* m_hashState = XXH64_createState();
     };
 } // namespace MobileGL::MG_Backend::DirectVulkan

MobileGL/MG_Backend/DirectVulkan/Renderer/VkClearManager.cpp

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

MobileGL/MG_Backend/DirectVulkan/Renderer/VkRenderPassManager.cpp

@@ -831,6 +831,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         // recreated since (texture + renderbuffer image epochs), and no pending clear (which alters
         // load ops). Any of these differing forces the full recompute below. Portable to VK 1.1.
         if (activeRenderPass != nullptr && m_rpFastValid && m_rpFastFbo == &fbo &&
+            m_rpFastFboLifetimeId == fbo.GetLifetimeId() &&
             m_rpFastFboVersion == fbo.GetObjectVersion() && m_rpFastSwapchainIndex == swapchainImageIndex &&
             m_rpFastTexEpoch == m_textureManager.GetTextureImageEpoch() &&
             m_rpFastRbEpoch == m_renderbufferImageEpoch &&
@@ -855,6 +856,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             // epochs AFTER ComputeHash: its attachment SyncTexture can create an image (bump the epoch).
             m_rpFastValid = true;
             m_rpFastFbo = &fbo;
+            m_rpFastFboLifetimeId = fbo.GetLifetimeId();
             m_rpFastFboVersion = fbo.GetObjectVersion();
             m_rpFastSwapchainIndex = swapchainImageIndex;
             m_rpFastTexEpoch = m_textureManager.GetTextureImageEpoch();
@@ -1507,7 +1509,23 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             ClearAttachmentPayload clearPayload{};
             SharedPtr<MG_State::GLState::ITextureObject> liveTexture;
             if (pending.hasInlinePayload) {
-                clearPayload = pending.inlinePayload;
+                // The inline payload was snapshotted when the entry was CREATED, but the
+                // clear VALUE is not part of the entry's hash - a cache hit with a newer
+                // glClear would replay the creation-time value and drop the new one (the
+                // texture path below is immune because it re-reads the live payload).
+                // Same defense as ClearAttachmentsOnActiveRenderPass: prefer the live
+                // pending clear, fall back to the snapshot only when none is queued.
+                if (s_renderPassManager != nullptr &&
+                    s_renderPassManager->GetPendingRenderbufferClear(pending.renderbuffer, clearPayload)) {
+                    if ((clearPayload.mask & GL_COLOR_BUFFER_BIT) != 0 && pending.renderbuffer != nullptr &&
+                        MG_Util::GetBaseInternalFormatComponentCount(pending.renderbuffer->GetInternalFormat()) ==
+                            3) {
+                        // RGB renderbuffers are backed by an RGBA image; the missing alpha reads as 1.
+                        ForceOpaqueClearAlpha(clearPayload);
+                    }
+                } else {
+                    clearPayload = pending.inlinePayload;
+                }
             } else {
                 if (pending.key.texture == nullptr ||
                     !s_clearManager->GetPendingClear(pending.key, clearPayload, liveTexture)) {

MobileGL/MG_Backend/DirectVulkan/Renderer/VkRenderPassManager.h

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

MobileGL/MG_Backend/DirectVulkan/Renderer/VkTextureManager.cpp

@@ -1993,6 +1993,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                         texture.GetExternalIndex(),
                         MG_Util::ConvertTextureUploadTargetToString(uploadTarget).c_str(),
                         static_cast<Int>(format), static_cast<Uint32>(imageInfo.usage));
+                // The preserved image was written by GPU work that may still be in flight
+                // (preserve requires layout != UNDEFINED); park it on the deferred ring
+                // like every other destruction path instead of letting the unique_ptr
+                // destroy it synchronously under the GPU.
+                if (preservedResource) {
+                    DeferResourceRelease(Move(*preservedResource));
+                }
                 return false;
             }
         }
@@ -2015,6 +2022,12 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                     static_cast<Int>(imageInfo.samples), static_cast<Int>(imageInfo.format));
             resource.image = VK_NULL_HANDLE;
             resource.allocation = nullptr;
+            // Same as the probe failure above: the preserved live image must go through
+            // the deferred ring, never a synchronous destructor while frames that
+            // reference it are still in flight.
+            if (preservedResource) {
+                DeferResourceRelease(Move(*preservedResource));
+            }
             return false;
         }
         ++m_textureImageEpoch; // a new attachment image invalidates cached render passes

MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp

@@ -3323,6 +3323,11 @@ void main() {
                 indexView.indexByteSize > bufferSize - indexView.indexByteOffset) {
                 return false;
             }
+            // Recorded-but-unexecuted GPU writes (XFB capture, SSBO, storage texel
+            // buffer) land in the coherent mapping this scan is about to read;
+            // submit-and-wait first, exactly like the restart-index rewrite does.
+            // A no-op unless the gpu-write flag is set.
+            indexBufferShared->SyncGpuWrites();
             indexBufferShared->SyncPersistentMappedRange();
             indexBytes = indexBufferShared->MappedData() + indexView.indexByteOffset;
         } else {
@@ -3560,6 +3565,16 @@ void main() {
                                          const Uint8* sourceData, SizeT sourceStride,
                                          SizeT elementSize, SizeT elementCount,
                                          BufferSlice& outSlice) -> Bool {
+            // A resolved stride of 0 is the binding model's "never advance" (see the
+            // factory's layout notes): exactly one element is converted and every vertex
+            // reads it. That single element is read at offset 0, so the stride is never
+            // actually used - but both converters reject 0 as a degenerate input, which
+            // made the documented single-element conversion unreachable and silently
+            // dropped every draw using such a binding. Substitute the element's own
+            // size; the caller's cache key still carries the distinct stride 0.
+            if (sourceStride == 0 && elementCount == 1) {
+                sourceStride = elementSize;
+            }
             const void* uploadData = nullptr;
             VkDeviceSize uploadSize = 0;
             switch (conversion) {
@@ -3693,6 +3708,12 @@ void main() {
                     return false;
                 }
 
+                // A GPU-written source (XFB capture, SSBO, storage texel buffer) has its
+                // bytes produced by commands that are merely RECORDED at this point, and
+                // MappedData() aliases the coherent GPU memory they will write into -
+                // converting now would read pre-write garbage. Submit-and-wait first,
+                // mirroring the restart-index rewrite; a flag-test no-op otherwise.
+                sourceBufferShared->SyncGpuWrites();
                 sourceBufferShared->SyncPersistentMappedRange();
                 const SizeT availableElementCount =
                     sourceStride == 0 ? 1 : 1 + (sourceSize - baseOffset - elementSize) / sourceStride;
@@ -3986,7 +4007,7 @@ void main() {
             // Skips the per-draw GetBackendResource chase into a cold resource object.
             Bool sliceStillValid = false;
             const Uint64 frameSerial = m_bufferManager.GetFrameSerial();
-            if (indexMemo->indexFrameSerial == frameSerial &&
+            if (indexMemo->indexFrameSerial == frameSerial && !indexMemo->indexBufferMapped &&
                 indexMemo->indexSliceEpochCounter == m_bufferManager.GetSliceEpochCounter()) {
                 sliceStillValid = true;
             }
@@ -4049,6 +4070,9 @@ void main() {
                 indexMemo->indexVkBuffer = slice.buffer;
                 indexMemo->indexSliceOffset = slice.offset;
                 indexMemo->indexFrameSerial = m_bufferManager.GetFrameSerial();
+                // A host-mapped EBO can mutate its shadow with no epoch bump; the hit
+                // path declines on this flag (mirror of anyBufferMapped).
+                indexMemo->indexBufferMapped = indexBufferShared->IsMapped();
             }
         }
         const VkDeviceSize indexBindOffset =
@@ -5718,6 +5742,22 @@ void main() {
         if (program.GetBackendStateVersion() != snap.programVersion) {
             return false;
         }
+        // glBegin/EndTransformFeedback moves no key this fast path otherwise observes
+        // (the design makes capture a compile-option FLAG precisely because no version
+        // bumps, VulkanRenderer.h's pipeline-memo note) - but the snapshot bakes that
+        // flag into resolvedTransformFlags and the pipeline. Recompute the one dynamic
+        // bit (the full path's exact predicate) and decline on a mismatch, or the first
+        // captured draw after glBeginTransformFeedback would bind the undecorated
+        // variant and silently capture nothing while the CPU bookkeeping advances.
+        const Bool wantsXfbCapture = m_transformFeedbackFeatureEnabled &&
+                                     MG_State::pGLContext->IsTransformFeedbackActive() &&
+                                     program.GetTransformFeedbackVaryingCount() > 0;
+        const Bool snapHasXfbCapture =
+            static_cast<Bool>(ProgramFactory::CompileOptionFlags(snap.resolvedTransformFlags) &
+                              ProgramFactory::CompileOptionBit::XfbCapture);
+        if (wantsXfbCapture != snapHasXfbCapture) {
+            return false;
+        }
         // A changed VAO does NOT decline: the VAO only feeds the pipeline's vertex
         // input state (re-resolved below through the layout-keyed memo, so N VAOs
         // sharing one attribute layout share one pipeline) and the vertex/index
@@ -5731,6 +5771,7 @@ void main() {
         const auto& drawFbo =
             MG_State::pGLContext->GetFramebufferBindingSlot(FramebufferTarget::Draw).GetBoundObject();
         if (static_cast<const void*>(drawFbo.get()) != snap.drawFbo ||
+            drawFbo->GetLifetimeId() != snap.drawFboLifetimeId ||
             drawFbo->GetObjectVersion() != snap.fboVersion) {
             return false;
         }
@@ -5914,8 +5955,14 @@ void main() {
         }
         const Uint64 samplingResolutionGeneration = MG_State::pGLContext->GetSamplingResolutionGeneration();
         if (samplingResolutionGeneration != snap.samplingResolutionGeneration) {
-            snap.samplingResolutionGeneration = samplingResolutionGeneration;
-            samplerDescriptorsUnchanged = false;
+            // Decline, not re-arm: snap.resolvedTransformFlags bakes the
+            // ExplicitLod0Sampling verdict, which reads the effective sampler's
+            // filters/aniso/LOD range - exactly the state this counter tracks.
+            // Re-arming the stamp here would rebuild the descriptors but keep the
+            // stale SPIR-V variant forever (every later draw compares equal again).
+            // Same shape as the erase-epoch declines above; costs one full-path draw
+            // per sampler/shape change, and the full path's LOD memo re-probes.
+            return false;
         }
 
         // Everything the full path would re-resolve is provably unchanged - or, for
@@ -6095,11 +6142,18 @@ void main() {
             const Uint64 lodProgramLifetimeId = program.GetLifetimeId();
             const Uint32 lodProgramVersion = program.GetBackendStateVersion();
             const Uint64 lodBindGeneration = MG_State::pGLContext->GetTextureBindGeneration();
+            // The probe also reads the EFFECTIVE sampler's filters/aniso/LOD range
+            // (ProgramSamplesOnlySingleLevelTextures), and those setters bump ONLY the
+            // sampling-resolution generation - not the texture params version the sum
+            // below covers. Without this key a filter/aniso change would keep serving
+            // the stale verdict.
+            const Uint64 lodSamplingGeneration = MG_State::pGLContext->GetSamplingResolutionGeneration();
             Bool lodMemoHit = false;
             if (m_lastLodDecisionValid && m_lastSampledSetValid &&
                 m_lastLodProgramLifetimeId == lodProgramLifetimeId &&
                 m_lastLodProgramVersion == lodProgramVersion &&
-                m_lastLodBindGeneration == lodBindGeneration && m_lastLodBaseFlags == transformFlags &&
+                m_lastLodBindGeneration == lodBindGeneration &&
+                m_lastLodSamplingGeneration == lodSamplingGeneration && m_lastLodBaseFlags == transformFlags &&
                 m_lastSampledSetProgramLifetimeId == lodProgramLifetimeId &&
                 m_lastSampledSetProgramVersion == lodProgramVersion &&
                 m_lastSampledSetBindGeneration == lodBindGeneration) {
@@ -6124,6 +6178,7 @@ void main() {
                 m_lastLodProgramLifetimeId = lodProgramLifetimeId;
                 m_lastLodProgramVersion = lodProgramVersion;
                 m_lastLodBindGeneration = lodBindGeneration;
+                m_lastLodSamplingGeneration = lodSamplingGeneration;
                 m_lastLodBaseFlags = baseFlags;
                 m_lastLodResultFlags = transformFlags;
                 m_lastLodParamsSum = 0;  // filled below once the sampled set is known
@@ -6467,6 +6522,7 @@ void main() {
                 snap.vaoLifetimeId = vao.GetLifetimeId();
                 snap.vaoConfigVersion = vao.GetConfigVersion();
                 snap.drawFbo = drawFbo.get();
+                snap.drawFboLifetimeId = drawFbo->GetLifetimeId();
                 snap.fboVersion = drawFbo->GetObjectVersion();
                 snap.drawFboIsDefault = drawFboIsDefault;
                 snap.viewportCount = ResolveDrawViewportCount(programObj.writesViewportIndexBuiltin);
@@ -13825,6 +13881,15 @@ void main() {
         VkPipeline pipeline = VK_NULL_HANDLE;
         VK_VERIFY(vkCreateComputePipelines(m_device, VK_NULL_HANDLE, 1, &pipelineInfo, nullptr, &pipeline),
                   "GetOrCreateComputePipeline, vkCreateComputePipelines");
+        // A failed creation must never be memoized - same contract as
+        // PipelineFactory::GetOrCreatePipeline: caching the null would serve it back
+        // for the rest of the process and every dispatch of this program would be
+        // silently skipped. Retrying costs one failed vkCreateComputePipelines per
+        // dispatch, which is the correct price.
+        if (pipeline == VK_NULL_HANDLE) {
+            MGLOG_E("GetOrCreateComputePipeline: vkCreateComputePipelines failed; not caching the failure");
+            return VK_NULL_HANDLE;
+        }
         m_computePipelines.emplace(programObj.hash, pipeline);
         return pipeline;
     }

MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.h

@@ -807,6 +807,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Uint32 m_lastLodProgramVersion = 0;
         Uint64 m_lastLodBindGeneration = 0;
         Uint64 m_lastLodParamsSum = 0;
+        // Sampling-resolution generation at probe time. The probe reads the effective
+        // sampler's filters/aniso/LOD range, whose setters bump only this counter -
+        // the params-version sum above never moves for them.
+        Uint64 m_lastLodSamplingGeneration = 0;
         ProgramFactory::CompileOptionFlags m_lastLodBaseFlags = {};
         ProgramFactory::CompileOptionFlags m_lastLodResultFlags = {};
 
@@ -844,6 +848,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             Uint64 vaoLifetimeId = 0;
             Uint32 vaoConfigVersion = 0;
             const void* drawFbo = nullptr;
+            // Never-reused lifetime id beside the raw pointer + Uint16 version: a
+            // deleted FBO recycled at the same address with the same fresh version
+            // count would otherwise compare equal (same ABA as the render-pass
+            // manager's fast-path memo).
+            Uint64 drawFboLifetimeId = 0;
             Uint16 fboVersion = 0;
             Bool drawFboIsDefault = false;
             Uint renderStateVersion = 0;
@@ -1067,6 +1076,14 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             VkBuffer indexVkBuffer = VK_NULL_HANDLE;
             VkDeviceSize indexSliceOffset = 0;
             Uint64 indexFrameSerial = 0;
+            // The EBO carried a host map when the slice was recorded - the mirror of
+            // anyBufferMapped on the vertex half. A shadow-backed (non-adopted)
+            // persistent map mutates its shadow with no API call and no epoch bump, so
+            // the one-compare rescue must decline and re-run the acquire, whose
+            // SyncPersistentMappedRange is the push-down. A map taken AFTER the record
+            // is already covered: AcquirePersistentMap bumps the slice epoch for the
+            // request itself, adopted or declined.
+            Bool indexBufferMapped = false;
 
             // Bound per draw (first bindingCount elements).
             VkBuffer vkBuffers[kMaxBindings] = {};

MobileGL/MG_Impl/GLImpl/Program/GL_Program.cpp

@@ -1057,21 +1057,20 @@ namespace MobileGL::MG_Impl::GLImpl {
             return;
         }
 
-        static Bool allowVSOnlyPrograms;
-        static Bool initialized = false;
-        if (!initialized) {
-            const auto& activeBackendObject = MG_Backend::pActiveBackendObject;
-            if (!activeBackendObject) {
-                MGLOG_E_ONCE("activeBackendObject is not initialized!");
-                return;
-            }
-            const auto& rendererInfo = activeBackendObject->GetRendererInfo();
-            allowVSOnlyPrograms = (Int)rendererInfo.StaticBackendCapability.AllowVSOnlyPrograms;
-        }
+        // Read fresh every link, never latched in a static: the capability is
+        // per-backend, and a latch would freeze it across a backend teardown +
+        // re-initialization (the previous function-static memo here never even set
+        // its own initialized flag, so it re-read every call anyway - this makes
+        // the always-fresh behavior the stated one). A struct-field read per
+        // glLinkProgram costs nothing.
         const auto& activeBackendObject = MG_Backend::pActiveBackendObject;
-        if (activeBackendObject) {
-            programObject->SetMaxFragmentOutputColorNumber(activeBackendObject->GetDynamicParameters().MaxDrawBuffers);
+        if (!activeBackendObject) {
+            MGLOG_E_ONCE("activeBackendObject is not initialized!");
+            return;
         }
+        const Bool allowVSOnlyPrograms =
+            activeBackendObject->GetRendererInfo().StaticBackendCapability.AllowVSOnlyPrograms;
+        programObject->SetMaxFragmentOutputColorNumber(activeBackendObject->GetDynamicParameters().MaxDrawBuffers);
         programObject->Link(!allowVSOnlyPrograms);
     }
 

MobileGL/MG_Impl/GLImpl/Query/GL_Query.cpp

@@ -648,4 +648,39 @@ namespace MobileGL::MG_Impl::GLImpl {
         if (!ValidateQueryStreamIndex(__FUNCTION__, target, index)) return;
         GetQueryiv(target, pname, params);
     }
+
+    void DestroyAllQueryObjects() {
+        // Detach the registry under the lock, release outside it - same discipline
+        // (and the same accepted teardown race) as DestroyAllSyncObjects. Without
+        // this drain, every query the app left undeleted survived full library
+        // teardown in the process-global registry: the objects and their backend
+        // wrappers leaked across Destroy/Initialize cycles, stale ids kept
+        // answering IsQuery == GL_TRUE in the re-initialized library, and a later
+        // glDeleteQueries could hand the OLD backend's handle to a DIFFERENT
+        // backend's DeleteBackendQuery, which casts it to the wrong wrapper type.
+        UnorderedMap<GLuint, QueryObject*> orphans;
+        {
+            const std::lock_guard<std::mutex> lock(g_queryObjectsMutex);
+            orphans.swap(g_liveQueryObjects);
+            g_activeTimeElapsedQueryId = 0;
+            g_activePrimitivesWrittenQueryId = 0;
+            g_activePrimitivesGeneratedQueryId = 0;
+            g_activeSamplesPassedQueryId = 0;
+        }
+        if (orphans.empty()) {
+            return;
+        }
+        // Backend handles must be released by the backend that created them, so
+        // this runs while the function table is still populated. Both backends'
+        // DeleteBackendQuery are generation-guarded, so a handle whose renderer
+        // or ES context is already gone frees only the wrapper.
+        const auto deleteBackendQuery = MG_Backend::gBackendFunctionsTable.GL.DeleteBackendQuery;
+        for (const auto& [_, queryObject] : orphans) {
+            if (deleteBackendQuery && queryObject->backendHandle) {
+                deleteBackendQuery(queryObject->backendHandle);
+            }
+            delete queryObject;
+        }
+        MGLOG_D("DestroyAllQueryObjects: reclaimed %zu query object(s) the app left undeleted", orphans.size());
+    }
 } // namespace MobileGL::MG_Impl::GLImpl

MobileGL/MG_Impl/GLImpl/Query/GL_Query.h

@@ -29,4 +29,13 @@ namespace MobileGL::MG_Impl::GLImpl {
     void GetQueryBufferObjecti64v(GLuint id, GLuint buffer, GLenum pname, GLintptr offset);
     void GetQueryBufferObjectui64v(GLuint id, GLuint buffer, GLenum pname, GLintptr offset);
     void QueryCounter(GLuint id, GLenum target);
+    // Destroys every still-registered query object exactly as DeleteQueries would.
+    // GL requires queries to die with their context; called only from full library
+    // teardown (DestroyImpl), where no context survives on any thread, so the
+    // process-global registry can be drained wholesale. Must run while the backend
+    // function table is still populated: each backend handle has to be released by
+    // the backend that created it, never by a later re-initialized one (whose
+    // DeleteBackendQuery would cast the wrapper to the wrong backend's type).
+    // Same contract as DestroyAllSyncObjects.
+    void DestroyAllQueryObjects();
 } // namespace MobileGL::MG_Impl::GLImpl

MobileGL/MG_State/GLState/Core.cpp

@@ -646,9 +646,17 @@ namespace MobileGL::MG_State {
             for (SizeT stage = 0; stage < ProgramPipelineObject::kGraphicsStageCount; ++stage) {
                 const auto& stageProgram = pipeline->GetStageProgram(static_cast<ShaderStage>(stage));
                 if (!stageProgram) continue;
-                for (const auto& shader : stageProgram->GetAttachedShaders()) {
-                    if (!shader || static_cast<SizeT>(shader->GetShaderStage()) != stage) continue;
-                    composite->AttachShader(shader);
+                // The stage program contributes the shaders its LAST LINK consumed, never
+                // its live attach list: per GL 4.6 7.3/7.4 a pipeline stage executes the
+                // stage program as last linked - glAttachShader and glCompileShader take
+                // effect only at the program's next link - and neither of those moves the
+                // link version this cache keys on, so reading live state here would let a
+                // post-link attach or recompile leak into the composite while the signature
+                // still hits. The pinned (source, node) makes the composite's Link()
+                // consume the very inputs that link consumed.
+                for (const auto& ref : stageProgram->GetLinkedShaderSnapshot()) {
+                    if (!ref.shader || static_cast<SizeT>(ref.shader->GetShaderStage()) != stage) continue;
+                    composite->AttachShaderWithPinnedLinkInput(ref);
                     anyStage = true;
                 }
             }

MobileGL/MG_State/GLState/FramebufferState/FramebufferObject.cpp

@@ -9,7 +9,18 @@
 #include "FramebufferObject.h"
 #include "MG_Util/Types.h"
 
+#include <atomic>
+
 namespace MobileGL::MG_State::GLState {
+    // Starts at 1 so a zero-initialized memo slot can never carry a live object's id.
+    // Atomic for the same reason as the VAO counter: it costs nothing, and a duplicate
+    // id would resurrect exactly the ABA this id exists to kill.
+    static std::atomic<Uint64> s_nextFramebufferLifetimeId{1};
+
+    Uint64 FramebufferObject::AllocateLifetimeId() {
+        return s_nextFramebufferLifetimeId.fetch_add(1, std::memory_order_relaxed);
+    }
+
     // FramebufferAttachmentObject
     FramebufferAttachmentObject::FramebufferAttachmentObject(
         const SharedPtr<MG_State::GLState::ITextureObject>& texture, TextureUploadTarget textureUploadTarget, Int level,

MobileGL/MG_State/GLState/FramebufferState/FramebufferObject.h

@@ -148,13 +148,25 @@ namespace MobileGL {
 
             Uint16 GetObjectVersion() const { return m_objectVersion; }
 
+            // Globally-unique, never-reused id for THIS object's lifetime - the same
+            // contract as VertexArrayObject::GetLifetimeId(), and needed for the same
+            // reason: neither the GL name nor the heap address can tell a
+            // deleted-and-recreated framebuffer from the original, and m_objectVersion
+            // starts at 0 for every new object, so a backend memo keyed on
+            // (pointer, version) alone would silently inherit the dead object's entry
+            // (see VkRenderPassManager's per-draw fast-path memo).
+            Uint64 GetLifetimeId() const { return m_lifetimeId; }
+
             Uint GetExternalIndex() const;
             Bool IsDefaultFramebuffer() const { return m_externalIndex == 0; }
 
         private:
+            static Uint64 AllocateLifetimeId();
+
             void BumpAttachmentVersion(FramebufferAttachmentType type);
 
             const Uint m_externalIndex = 0;
+            const Uint64 m_lifetimeId = AllocateLifetimeId();
             FramebufferAttachmentObjectArray m_attachmentObjects;
             FramebufferAttachmentVersionArray m_attachmentVersions;
 

MobileGL/MG_State/GLState/ProgramState/ProgramObject.cpp

@@ -393,6 +393,14 @@ namespace MobileGL::MG_State::GLState {
         return true;
     }
 
+    bool ProgramObject::AttachShaderWithPinnedLinkInput(const LinkedShaderRef& ref) {
+        if (!AttachShader(ref.shader)) {
+            return false;
+        }
+        m_pinnedLinkInputs[ref.shader.get()] = ref;
+        return true;
+    }
+
     SizeT ProgramObject::DetachShader(const SharedPtr<ShaderObject>& shader) {
         MGLOG_D("DetachShader called for shader %p from ProgramObject %u", shader.get(), m_externalIndex);
         if (!ShaderIsAttached(shader)) {
@@ -475,6 +483,8 @@ namespace MobileGL::MG_State::GLState {
             AddDefaultFragmentShaderIfMissing();
         }
         if (m_shaders.empty()) {
+            // This IS the last link now, and it consumed nothing.
+            m_linkedShaderSnapshot.clear();
             m_artifacts.infoLog = "No shader objects are attached to program.";
             MGLOG_E("ProgramObject %u: Link failed - no shader objects attached.", m_externalIndex);
             return;
@@ -505,8 +515,19 @@ namespace MobileGL::MG_State::GLState {
         Vector<SharedPtr<ShaderCompileTask>> deps;
         deps.reserve(m_shaders.size());
         task->in.shaders.reserve(m_shaders.size());
+        m_linkedShaderSnapshot.clear();
+        m_linkedShaderSnapshot.reserve(m_shaders.size());
         for (const auto& shader : m_shaders) {
-            const SharedPtr<ShaderCompileTask>& node = shader->CompiledNodeForLink();
+            // A pipeline composite pins the (source, node) each stage program's LAST link
+            // consumed (AttachShaderWithPinnedLinkInput); an ordinary program takes the
+            // shader's current ones. Without the pin a post-link recompile would leak a
+            // shader the stage program never linked into the composite.
+            SharedPtr<const String> sourcePtr = shader->GetShaderSourcePtr();
+            SharedPtr<ShaderCompileTask> node = shader->CompiledNodeForLink();
+            if (const auto pinned = m_pinnedLinkInputs.find(shader.get()); pinned != m_pinnedLinkInputs.end()) {
+                sourcePtr = pinned->second.source;
+                node = pinned->second.node;
+            }
             if (node) {
                 // This link is now an observer of that node's result, and the ShaderObject is
                 // no longer the only route to it: without the marker, the ordinary
@@ -515,7 +536,10 @@ namespace MobileGL::MG_State::GLState {
                 node->MarkLinkReferenced();
                 if (!node->IsTerminal()) deps.push_back(node);
             }
-            task->in.shaders.push_back({shader->GetShaderStage(), shader->GetShaderSourcePtr(), node});
+            task->in.shaders.push_back({shader->GetShaderStage(), sourcePtr, node});
+            // What "as last linked" will mean for this program from now on - the pipeline
+            // composite cache rebuilds from exactly this set (GetProgramForDraw).
+            m_linkedShaderSnapshot.push_back({shader, sourcePtr, node});
         }
 
         // Phase B of the same link: SPIR-V generation, spirv-opt and the global-UBO routing

MobileGL/MG_State/GLState/ProgramState/ProgramObject.h

@@ -60,6 +60,26 @@ namespace MobileGL::MG_State::GLState {
 
         Vector<SharedPtr<ShaderObject>>& GetAttachedShaders();
         const Vector<SharedPtr<ShaderObject>>& GetAttachedShaders() const;
+
+        // One shader exactly as this program's last Link() consumed it: the object, the
+        // source snapshot, and the compile node taken at that link's enqueue. GL 4.6 7.3/7.4
+        // makes this triple - not the live attach list, not the shader's current compile -
+        // what a program pipeline stage executes ("as last linked"): glAttachShader and
+        // glCompileShader take effect only at the program's next link, yet neither moves
+        // m_linkVersion, so anything keyed on the link generation must consume this
+        // snapshot rather than re-read the live state.
+        struct LinkedShaderRef {
+            SharedPtr<ShaderObject> shader;
+            SharedPtr<const String> source;
+            SharedPtr<ShaderCompileTask> node;
+        };
+        // The last link's full input set; empty when this program has never linked (or its
+        // last link had no shaders attached). GL-thread-owned, rebuilt in Link()'s prologue.
+        const Vector<LinkedShaderRef>& GetLinkedShaderSnapshot() const { return m_linkedShaderSnapshot; }
+        // Pipeline-composite attach: AttachShader plus a pin that makes THIS program's
+        // Link() consume ref's (source, node) instead of the shader's current ones, so a
+        // post-link recompile of the stage program's shader cannot leak into the composite.
+        bool AttachShaderWithPinnedLinkInput(const LinkedShaderRef& ref);
         const String& GetInfoLog() const { return Artifacts().infoLog; }
         // glCreateShaderProgramv folds the shader's compile log into the program's log, which
         // is the only place a caller can read it from once the shader name is gone.
@@ -786,6 +806,13 @@ namespace MobileGL::MG_State::GLState {
         // order - and the name is the only coordinate all three agree on. Absent from the map
         // means "never rebound", and the shader's declared binding still stands.
         void SetShaderStorageBlockBinding(const String& blockName, Uint binding) {
+            // Equality bail-out like SetUniformBlockBinding's: the pipeline composite
+            // mirror replays every override each draw, and without this every replay
+            // would churn m_blockBindingVersion and rebuild whatever keys on it.
+            const auto it = Artifacts().shaderStorageBlockBinding.find(blockName);
+            if (it != Artifacts().shaderStorageBlockBinding.end() && it->second == static_cast<Int>(binding)) {
+                return;
+            }
             Artifacts().shaderStorageBlockBinding[blockName] = static_cast<Int>(binding);
             // Deliberately NOT m_backendStateVersion: Espryt's entry point never forces a
             // program build off this, and bumping that version would start doing so. The
@@ -1223,6 +1250,13 @@ namespace MobileGL::MG_State::GLState {
         // glGetAttachedShaders / GL_ATTACHED_SHADERS / the orphan-shader sweep need no join.
         Vector<SharedPtr<ShaderObject>> m_shaders;
         Vector<SharedPtr<ShaderObject>> m_detachedShaders; // Store detached shaders and remove on next link
+        // See GetLinkedShaderSnapshot. Holding the SharedPtrs here is deliberate: the
+        // "as last linked" set must survive detach-and-delete of its shaders (the
+        // glCreateShaderProgramv shape) until the next link replaces it.
+        Vector<LinkedShaderRef> m_linkedShaderSnapshot;
+        // See AttachShaderWithPinnedLinkInput. Populated only on pipeline composites,
+        // which never detach, so entries need no removal path. GL-thread-owned.
+        UnorderedMap<const ShaderObject*, LinkedShaderRef> m_pinnedLinkInputs;
 
         // Link INPUTS (all "take effect at the next link" per GL): glBindAttribLocation,
         // glBindFragDataLocation(Indexed), glTransformFeedbackVaryings, and the draw-buffer

MobileGL/MG_State/GLState/ProgramState/ShaderObject.cpp

@@ -140,6 +140,13 @@ namespace MobileGL::MG_State::GLState {
     }
 
     void ShaderObject::Compile() {
+        // The compile-environment snapshot is taken HERE, on the GL thread, and handed to
+        // the job. Everything the pipeline needs to know about the device comes through it,
+        // never through pActiveBackendObject - that is what makes the body movable.
+        // Hoisted above the memo check because the memo must be env-disciplined too (below).
+        const SharedPtr<const MG_Util::ShaderTranspiler::CompileEnv> env =
+            MG_Util::ShaderTranspiler::GetCurrentCompileEnv();
+
         // P0b layer 1, as a tri-state: the memo is "the node in m_compiled was built from
         // the string m_source still points at". SetShaderSource only swaps that pointer when
         // the text actually differs, so this is a pointer compare, and it covers Pending as
@@ -152,7 +159,18 @@ namespace MobileGL::MG_State::GLState {
         // ClaimParsedShader's on-demand re-parse needs - a real recompile would have handed
         // the next link a fresh parse, the no-op hands it a fresh re-parse of the identical
         // source instead. Same result, one parse either way.
-        if (HasMemoizedCompile()) return;
+        //
+        // The environment joins the check (ShaderSourceKey.h's memo-hazard rule: a memo
+        // must never be handed back under an environment other than the one it was
+        // computed against). Layers 2 and 3 key on the fingerprint, but this memo sits
+        // ABOVE both, so without this compare a node computed against a dead environment
+        // - e.g. a compute shader rejected against the pre-capability fallback limits -
+        // would keep answering forever while a fresh object with byte-identical source
+        // compiles fine. The fingerprint is a content hash, so a republish of identical
+        // capabilities still hits.
+        if (HasMemoizedCompile() && m_compiled->env != nullptr && m_compiled->env->fingerprint == env->fingerprint) {
+            return;
+        }
 
         // Two reasons to stay on this thread, one rule. Without the async flag the whole
         // path must be byte-identical to the synchronous implementation, and a cache-less
@@ -168,12 +186,6 @@ namespace MobileGL::MG_State::GLState {
         // glMaxShaderCompilerThreadsKHR(0) and a flag-off build both bypass sharing exactly
         // as they bypass the pool, and their behaviour stays byte-identical to pre-stage-6.
         const Bool runOnPool = m_preprocessCache && MG_Util::Async::AsyncShaderCompileActive();
-
-        // The compile-environment snapshot is taken HERE, on the GL thread, and handed to
-        // the job. Everything the pipeline needs to know about the device comes through it,
-        // never through pActiveBackendObject - that is what makes the body movable.
-        const SharedPtr<const MG_Util::ShaderTranspiler::CompileEnv> env =
-            MG_Util::ShaderTranspiler::GetCurrentCompileEnv();
         const Uint64 sourceHash = ShaderPreprocessCache::HashSource(*m_source);
 
         // ---- P1 stage 6: adopt an equivalent compile instead of enqueueing a duplicate ----

MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/DemoteFloat64Pass.cpp

@@ -91,9 +91,15 @@ namespace MobileGL {
                     BlockRelayout(IRContext* irContext, Bool std140)
                         : m_irContext(irContext), m_std140(std140) {}
 
-                    // Size and alignment of `typeId`, applying every stride decoration it implies
-                    // on the way down. Zero size means "not a type this layout knows how to
-                    // describe"; the caller then leaves the block alone rather than guessing.
+                    // Size and alignment of `typeId`, QUEUING every offset/stride decoration it
+                    // implies on the way down. Zero size means "not a type this layout knows how
+                    // to describe"; the caller then leaves the block alone rather than guessing.
+                    // The queue is what makes that fallback honest: measurement must be
+                    // side-effect-free until it is known to succeed, or a mid-struct failure
+                    // would leave the block half-relaid-out - members before the failing one at
+                    // compacted 32-bit offsets, members after it at the original 64-bit ones, a
+                    // layout matching neither convention. Commit() flushes the queue and is
+                    // called only on a successful Measure of the whole block.
                     struct Extent {
                         Uint32 size = 0;
                         Uint32 alignment = 0;
@@ -108,7 +114,29 @@ namespace MobileGL {
                         return extent;
                     }
 
+                    // Flushes the decoration writes a successful Measure queued. Call exactly
+                    // once, only when Measure returned a non-zero size; a failed measurement's
+                    // queue dies with this per-block instance, leaving the module untouched.
+                    void Commit() {
+                        for (const PendingDecoration& pending : m_pendingWrites) {
+                            if (pending.member) {
+                                ApplyMemberDecoration(pending.targetId, pending.memberIndex, pending.decoration,
+                                                      pending.value);
+                            } else {
+                                ApplyTypeDecoration(pending.targetId, pending.decoration, pending.value);
+                            }
+                        }
+                        m_pendingWrites.clear();
+                    }
+
                 private:
+                    struct PendingDecoration {
+                        Bool member = false;
+                        Uint32 targetId = 0;
+                        Uint32 memberIndex = 0;
+                        spv::Decoration decoration = spv::Decoration::Offset;
+                        Uint32 value = 0;
+                    };
                     Extent MeasureUncached(Uint32 typeId) {
                         const Instruction* type = m_irContext->get_def_use_mgr()->GetDef(typeId);
                         if (type == nullptr) return {};
@@ -204,7 +232,17 @@ namespace MobileGL {
                         return length->GetSingleWordInOperand(0);
                     }
 
+                    // Queue-only during measurement; the module is mutated in Commit().
                     void SetTypeDecoration(Uint32 targetId, spv::Decoration decoration, Uint32 value) {
+                        m_pendingWrites.push_back({false, targetId, 0, decoration, value});
+                    }
+
+                    void SetMemberDecoration(Uint32 structId, Uint32 member, spv::Decoration decoration,
+                                             Uint32 value) {
+                        m_pendingWrites.push_back({true, structId, member, decoration, value});
+                    }
+
+                    void ApplyTypeDecoration(Uint32 targetId, spv::Decoration decoration, Uint32 value) {
                         for (Instruction& annotation : m_irContext->annotations()) {
                             if (annotation.opcode() != spv::Op::OpDecorate) continue;
                             if (annotation.GetSingleWordInOperand(0) != targetId) continue;
@@ -216,8 +254,8 @@ namespace MobileGL {
                         }
                     }
 
-                    void SetMemberDecoration(Uint32 structId, Uint32 member, spv::Decoration decoration,
-                                             Uint32 value) {
+                    void ApplyMemberDecoration(Uint32 structId, Uint32 member, spv::Decoration decoration,
+                                               Uint32 value) {
                         for (Instruction& annotation : m_irContext->annotations()) {
                             if (annotation.opcode() != spv::Op::OpMemberDecorate) continue;
                             if (annotation.GetSingleWordInOperand(0) != structId) continue;
@@ -233,6 +271,7 @@ namespace MobileGL {
                     IRContext* m_irContext = nullptr;
                     Bool m_std140 = true;
                     std::unordered_map<Uint32, Extent> m_extents;
+                    std::vector<PendingDecoration> m_pendingWrites;
                 };
             } // namespace
 
@@ -529,9 +568,12 @@ namespace MobileGL {
                         // A member shape the layout rules here do not describe. Leaving the block
                         // at its 64-bit offsets keeps the module valid for Vulkan; SPIRV-Cross will
                         // decline it for ESSL, which is the same outcome as before the demotion.
+                        // Nothing was written: Measure only queues, and the queue dies here.
                         MGLOG_D("DemoteFloat64Pass: block %%%u contains a member this pass cannot lay "
                                 "out; its 64-bit offsets are left in place",
                                 blockType->result_id());
+                    } else {
+                        relayout.Commit();
                     }
                 }