Remove feedback loop support from back-end.

include/platform/FeaturesVk.h

@@ -323,12 +323,6 @@ struct FeaturesVk : FeatureSetBase
         "enable_precision_qualifiers", FeatureCategory::VulkanFeatures,
         "Enable precision qualifiers in shaders", &members, "http://anglebug.com/3078"};
 
-    // Support Depth/Stencil rendering feedback loops by masking out the depth/stencil buffer.
-    // Manhattan uses this feature in a few draw calls.
-    Feature supportDepthStencilRenderingFeedbackLoops = {
-        "support_depth_stencil_rendering_feedback_loops", FeatureCategory::VulkanFeatures,
-        "Suport depth/stencil rendering feedback loops", &members, "http://anglebug.com/4490"};
-
     // Desktop (at least NVIDIA) drivers prefer combining barriers into one vkCmdPipelineBarrier
     // call over issuing multiple barrier calls with fine grained dependency information to have
     // better performance. http://anglebug.com/4633

src/libANGLE/renderer/RenderTargetCache.h

@@ -43,7 +43,7 @@ class RenderTargetCache final : angle::NonCopyable
     using RenderTargetArray = gl::AttachmentArray<RenderTargetT *>;
 
     const RenderTargetArray &getColors() const;
-    RenderTargetT *getDepthStencil(bool allowFeedbackLoop) const;
+    RenderTargetT *getDepthStencil() const;
 
     RenderTargetT *getColorDraw(const gl::FramebufferState &state, size_t colorIndex) const;
     RenderTargetT *getColorRead(const gl::FramebufferState &state) const;
@@ -56,7 +56,6 @@ class RenderTargetCache final : angle::NonCopyable
     RenderTargetT *mReadRenderTarget                         = nullptr;
     gl::AttachmentArray<RenderTargetT *> mColorRenderTargets = {};
     // We only support a single Depth/Stencil RenderTarget currently.
-    bool mDepthStencilFeedbackLoop           = false;
     RenderTargetT *mDepthStencilRenderTarget = nullptr;
 };
 
@@ -112,9 +111,9 @@ const gl::AttachmentArray<RenderTargetT *> &RenderTargetCache<RenderTargetT>::ge
 }
 
 template <typename RenderTargetT>
-RenderTargetT *RenderTargetCache<RenderTargetT>::getDepthStencil(bool allowFeedbackLoop) const
+RenderTargetT *RenderTargetCache<RenderTargetT>::getDepthStencil() const
 {
-    return (allowFeedbackLoop || !mDepthStencilFeedbackLoop) ? mDepthStencilRenderTarget : nullptr;
+    return mDepthStencilRenderTarget;
 }
 
 template <typename RenderTargetT>
@@ -147,7 +146,6 @@ angle::Result RenderTargetCache<RenderTargetT>::updateDepthStencilRenderTarget(
     const gl::Context *context,
     const gl::FramebufferState &state)
 {
-    mDepthStencilFeedbackLoop = state.hasDepthStencilFeedbackLoop();
     return updateCachedRenderTarget(context, state.getDepthOrStencilAttachment(),
                                     &mDepthStencilRenderTarget);
 }

src/libANGLE/renderer/d3d/d3d11/Framebuffer11.cpp

@@ -432,7 +432,7 @@ RenderTarget11 *Framebuffer11::getFirstRenderTarget() const
         }
     }
 
-    return mRenderTargetCache.getDepthStencil(true);
+    return mRenderTargetCache.getDepthStencil();
 }
 
 }  // namespace rx

src/libANGLE/renderer/d3d/d3d11/Framebuffer11.h

@@ -49,7 +49,7 @@ class Framebuffer11 : public FramebufferD3D
     }
     const RenderTarget11 *getCachedDepthStencilRenderTarget() const
     {
-        return mRenderTargetCache.getDepthStencil(true);
+        return mRenderTargetCache.getDepthStencil();
     }
 
     RenderTarget11 *getFirstRenderTarget() const;

src/libANGLE/renderer/d3d/d3d9/Framebuffer9.cpp

@@ -61,7 +61,7 @@ angle::Result Framebuffer9::clearImpl(const gl::Context *context,
                                       const ClearParameters &clearParams)
 {
     ANGLE_TRY(mRenderer->applyRenderTarget(context, mRenderTargetCache.getColors()[0],
-                                           mRenderTargetCache.getDepthStencil(true)));
+                                           mRenderTargetCache.getDepthStencil()));
 
     const gl::State &glState = context->getState();
     float nearZ              = glState.getNearPlane();
@@ -72,7 +72,7 @@ angle::Result Framebuffer9::clearImpl(const gl::Context *context,
     mRenderer->setScissorRectangle(glState.getScissor(), glState.isScissorTestEnabled());
 
     mRenderer->clear(clearParams, mRenderTargetCache.getColors()[0],
-                     mRenderTargetCache.getDepthStencil(true));
+                     mRenderTargetCache.getDepthStencil());
     return angle::Result::Continue;
 }
 

src/libANGLE/renderer/d3d/d3d9/Framebuffer9.h

@@ -50,7 +50,7 @@ class Framebuffer9 : public FramebufferD3D
 
     const RenderTarget9 *getCachedDepthStencilRenderTarget() const
     {
-        return mRenderTargetCache.getDepthStencil(true);
+        return mRenderTargetCache.getDepthStencil();
     }
 
     const gl::InternalFormat &getImplementationColorReadFormat(

src/libANGLE/renderer/vulkan/FramebufferVk.cpp

@@ -282,9 +282,7 @@ FramebufferVk::FramebufferVk(RendererVk *renderer,
     : FramebufferImpl(state),
       mBackbuffer(backbuffer),
       mFramebuffer(nullptr),
-      mActiveColorComponents(0),
-      mSupportDepthStencilFeedbackLoops(
-          renderer->getFeatures().supportDepthStencilRenderingFeedbackLoops.enabled)
+      mActiveColorComponents(0)
 {
     mReadPixelBuffer.init(renderer, VK_BUFFER_USAGE_TRANSFER_DST_BIT, kReadPixelsBufferAlignment,
                           kMinReadPixelsBufferSize, true);
@@ -422,33 +420,6 @@ angle::Result FramebufferVk::clearImpl(const gl::Context *context,
 
     bool scissoredClear = scissoredRenderArea != getRotatedCompleteRenderArea(contextVk);
 
-    // Special case for rendering feedback loops: clears are always valid in GL since they don't
-    // sample from any textures.
-    if ((clearDepth || clearStencil) && mState.hasDepthStencilFeedbackLoop())
-    {
-        // We currently don't handle scissored clears with rendering feedback loops.
-        ANGLE_VK_CHECK(contextVk, !scissoredClear, VK_ERROR_INCOMPATIBLE_DRIVER);
-
-        RenderTargetVk *depthStencilRT = mRenderTargetCache.getDepthStencil(true);
-        vk::ImageHelper *image         = &depthStencilRT->getImageForWrite();
-
-        ANGLE_TRY(contextVk->onImageTransferWrite(image->getAspectFlags(), image));
-        vk::CommandBuffer &commandBuffer = contextVk->getOutsideRenderPassCommandBuffer();
-
-        VkImageSubresourceRange range;
-        range.aspectMask     = image->getAspectFlags();
-        range.baseMipLevel   = depthStencilRT->getLevelIndex();
-        range.levelCount     = 1;
-        range.baseArrayLayer = depthStencilRT->getLayerIndex();
-        range.layerCount     = 1;
-
-        commandBuffer.clearDepthStencilImage(image->getImage(),
-                                             VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
-                                             clearDepthStencilValue, 1, &range);
-        clearDepth   = false;
-        clearStencil = false;
-    }
-
     // If there is nothing to clear, return right away (for example, if asked to clear depth, but
     // there is no depth attachment).
     if (!clearColor && !clearDepth && !clearStencil)
@@ -720,9 +691,7 @@ angle::Result FramebufferVk::readPixels(const gl::Context *context,
 
 RenderTargetVk *FramebufferVk::getDepthStencilRenderTarget() const
 {
-    // If we mask out depth/stencil feedback loops, do not allow the user to access the looped DS
-    // render target. Passing "false" to getDepthStencil forces a return of "nullptr" for loops.
-    return mRenderTargetCache.getDepthStencil(!mSupportDepthStencilFeedbackLoops);
+    return mRenderTargetCache.getDepthStencil();
 }
 
 RenderTargetVk *FramebufferVk::getColorDrawRenderTarget(size_t colorIndex) const
@@ -1144,7 +1113,7 @@ angle::Result FramebufferVk::blit(const gl::Context *context,
     if (blitDepthBuffer || blitStencilBuffer)
     {
         RenderTargetVk *readRenderTarget      = srcFramebufferVk->getDepthStencilRenderTarget();
-        RenderTargetVk *drawRenderTarget      = mRenderTargetCache.getDepthStencil(true);
+        RenderTargetVk *drawRenderTarget      = mRenderTargetCache.getDepthStencil();
         UtilsVk::BlitResolveParameters params = commonParams;
         params.srcLayer                       = readRenderTarget->getLayerIndex();
 
@@ -1446,7 +1415,7 @@ angle::Result FramebufferVk::invalidateImpl(ContextVk *contextVk,
     ANGLE_TRY(flushDeferredClears(contextVk, getRotatedCompleteRenderArea(contextVk)));
 
     const auto &colorRenderTargets           = mRenderTargetCache.getColors();
-    RenderTargetVk *depthStencilRenderTarget = mRenderTargetCache.getDepthStencil(true);
+    RenderTargetVk *depthStencilRenderTarget = mRenderTargetCache.getDepthStencil();
 
     // To ensure we invalidate the right renderpass we require that the current framebuffer be the
     // same as the current renderpass' framebuffer. E.g. prevent sequence like:

src/libANGLE/renderer/vulkan/FramebufferVk.h

@@ -255,7 +255,6 @@ class FramebufferVk : public FramebufferImpl
 
     vk::FramebufferDesc mCurrentFramebufferDesc;
     std::unordered_map<vk::FramebufferDesc, vk::FramebufferHelper> mFramebufferCache;
-    bool mSupportDepthStencilFeedbackLoops;
 
     vk::ClearValuesArray mDeferredClears;
 };

src/libANGLE/renderer/vulkan/RendererVk.cpp

@@ -1822,8 +1822,6 @@ void RendererVk::initFeatures(DisplayVk *displayVk, const ExtensionNameList &dev
     // Currently disabled by default: http://anglebug.com/3078
     ANGLE_FEATURE_CONDITION(&mFeatures, enablePrecisionQualifiers, false);
 
-    ANGLE_FEATURE_CONDITION(&mFeatures, supportDepthStencilRenderingFeedbackLoops, false);
-
     ANGLE_FEATURE_CONDITION(&mFeatures, preferAggregateBarrierCalls, isNvidia || isAMD || isIntel);
 
     // Currently disabled by default: http://anglebug.com/4324

src/tests/gl_tests/FramebufferTest.cpp

@@ -1658,11 +1658,9 @@ TEST_P(FramebufferTest_ES3, AttachmentStateChange)
 // The test emulates the read-only feedback loop in Manhattan.
 TEST_P(FramebufferTest_ES3, ReadOnlyDepthFeedbackLoopSupported)
 {
-    // Feedback loops not supported on D3D11 and may not ever be.
-    ANGLE_SKIP_TEST_IF(IsD3D11());
-
-    // Also this particular test doesn't work on Android despite similar support in Manhattan.
-    ANGLE_SKIP_TEST_IF(IsAndroid() && IsOpenGLES());
+    // Feedback loops are only supported on Vulkan.
+    // TODO(jmadill): Make GL extension. http://anglebug.com/4969
+    ANGLE_SKIP_TEST_IF(!IsVulkan());
 
     constexpr GLuint kSize = 2;
     glViewport(0, 0, kSize, kSize);
@@ -1725,11 +1723,9 @@ void main()
 // Tests corner cases with read-only depth-stencil feedback loops.
 TEST_P(FramebufferTest_ES3, ReadOnlyDepthFeedbackLoopStateChanges)
 {
-    // Feedback loops not supported on D3D11 and may not ever be.
-    ANGLE_SKIP_TEST_IF(IsD3D11());
-
-    // Also this particular test doesn't work on Android despite similar support in Manhattan.
-    ANGLE_SKIP_TEST_IF(IsAndroid() && IsOpenGLES());
+    // Feedback loops are only supported on Vulkan.
+    // TODO(jmadill): Make GL extension. http://anglebug.com/4969
+    ANGLE_SKIP_TEST_IF(!IsVulkan());
 
     constexpr GLuint kSize = 2;
     glViewport(0, 0, kSize, kSize);