Vulkan: Mask the alpha channel for draw when needed

src/libANGLE/renderer/vulkan/ContextVk.cpp

@@ -362,6 +362,17 @@ void ContextVk::popDebugGroup()
     UNIMPLEMENTED();
 }
 
+void ContextVk::updateClearColorMask(const gl::BlendState &blendState)
+{
+    mClearColorMask =
+        gl_vk::GetColorComponentFlags(blendState.colorMaskRed, blendState.colorMaskGreen,
+                                      blendState.colorMaskBlue, blendState.colorMaskAlpha);
+
+    FramebufferVk *framebufferVk = vk::GetImpl(mState.getState().getDrawFramebuffer());
+    mPipelineDesc->updateColorWriteMask(mClearColorMask,
+                                        framebufferVk->getEmulatedAlphaAttachmentMask());
+}
+
 void ContextVk::updateScissor(const gl::State &glState)
 {
     if (glState.isScissorTestEnabled())
@@ -417,14 +428,8 @@ void ContextVk::syncState(const gl::Context *context, const gl::State::DirtyBits
                 mPipelineDesc->updateBlendEquations(glState.getBlendState());
                 break;
             case gl::State::DIRTY_BIT_COLOR_MASK:
-            {
-                const gl::BlendState &blendState = glState.getBlendState();
-                mClearColorMask                  = gl_vk::GetColorComponentFlags(
-                    blendState.colorMaskRed, blendState.colorMaskGreen, blendState.colorMaskBlue,
-                    blendState.colorMaskAlpha);
-                mPipelineDesc->updateColorWriteMask(mClearColorMask);
+                updateClearColorMask(glState.getBlendState());
                 break;
-            }
             case gl::State::DIRTY_BIT_SAMPLE_ALPHA_TO_COVERAGE_ENABLED:
                 WARN() << "DIRTY_BIT_SAMPLE_ALPHA_TO_COVERAGE_ENABLED unimplemented";
                 break;
@@ -534,7 +539,7 @@ void ContextVk::syncState(const gl::Context *context, const gl::State::DirtyBits
                 WARN() << "DIRTY_BIT_READ_FRAMEBUFFER_BINDING unimplemented";
                 break;
             case gl::State::DIRTY_BIT_DRAW_FRAMEBUFFER_BINDING:
-                WARN() << "DIRTY_BIT_DRAW_FRAMEBUFFER_BINDING unimplemented";
+                updateClearColorMask(glState.getBlendState());
                 break;
             case gl::State::DIRTY_BIT_RENDERBUFFER_BINDING:
                 WARN() << "DIRTY_BIT_RENDERBUFFER_BINDING unimplemented";

src/libANGLE/renderer/vulkan/ContextVk.h

@@ -171,6 +171,7 @@ class ContextVk : public ContextImpl
                         vk::CommandBuffer **commandBufferOut,
                         bool *shouldApplyVertexArrayOut);
 
+    void updateClearColorMask(const gl::BlendState &blendState);
     void updateScissor(const gl::State &glState);
 
     RendererVk *mRenderer;

src/libANGLE/renderer/vulkan/FramebufferVk.cpp

@@ -203,11 +203,21 @@ gl::Error FramebufferVk::clear(const gl::Context *context, GLbitfield mask)
     const VkClearColorValue &clearColorValue = contextVk->getClearColorValue().color;
     for (size_t colorIndex : mState.getEnabledDrawBuffers())
     {
+        VkClearColorValue modifiedClearColorValue = clearColorValue;
         RenderTargetVk *colorRenderTarget = colorRenderTargets[colorIndex];
+
+        // Its possible we're clearing a render target that has no alpha channel but we represent it
+        // with a texture that has one. We must not affect its alpha channel no matter what the
+        // clear value is in that case.
+        if (mEmulatedAlphaAttachmentMask[colorIndex])
+        {
+            modifiedClearColorValue.float32[3] = 1.0;
+        }
+
         ASSERT(colorRenderTarget);
         vk::ImageHelper *image = colorRenderTarget->getImageForWrite(currentSerial, this);
         GLint mipLevelToClear  = (attachment->type() == GL_TEXTURE) ? attachment->mipLevel() : 0;
-        image->clearColor(clearColorValue, mipLevelToClear, 1, commandBuffer);
+        image->clearColor(modifiedClearColorValue, mipLevelToClear, 1, commandBuffer);
     }
 
     return gl::NoError();
@@ -369,9 +379,19 @@ gl::Error FramebufferVk::syncState(const gl::Context *context,
                 RenderTargetVk *renderTarget = mRenderTargetCache.getColors()[colorIndex];
                 if (renderTarget)
                 {
-                    const angle::Format &format = renderTarget->getImageFormat().textureFormat();
-                    updateActiveColorMasks(colorIndex, format.redBits > 0, format.greenBits > 0,
-                                           format.blueBits > 0, format.alphaBits > 0);
+                    const angle::Format &emulatedFormat =
+                        renderTarget->getImageFormat().textureFormat();
+                    updateActiveColorMasks(
+                        colorIndex, emulatedFormat.redBits > 0, emulatedFormat.greenBits > 0,
+                        emulatedFormat.blueBits > 0, emulatedFormat.alphaBits > 0);
+
+                    // TODO(lucferron): Add a test to trigger edge case where the framebuffer
+                    // attachment would change but not the binding.
+                    // http://anglebug.com/2597
+                    const angle::Format &sourceFormat =
+                        renderTarget->getImageFormat().angleFormat();
+                    mEmulatedAlphaAttachmentMask.set(
+                        colorIndex, sourceFormat.alphaBits == 0 && emulatedFormat.alphaBits > 0);
                 }
                 else
                 {
@@ -383,8 +403,8 @@ gl::Error FramebufferVk::syncState(const gl::Context *context,
     }
 
     mActiveColorComponents = gl_vk::GetColorComponentFlags(
-        mActiveColorComponentMasks[0].any(), mActiveColorComponentMasks[1].any(),
-        mActiveColorComponentMasks[2].any(), mActiveColorComponentMasks[3].any());
+        mActiveColorComponentMasksForClear[0].any(), mActiveColorComponentMasksForClear[1].any(),
+        mActiveColorComponentMasksForClear[2].any(), mActiveColorComponentMasksForClear[3].any());
 
     mRenderPassDesc.reset();
     renderer->releaseObject(getStoredQueueSerial(), &mFramebuffer);
@@ -626,7 +646,7 @@ gl::Error FramebufferVk::clearWithDraw(const gl::Context *context,
     // This pipeline desc could be cached.
     vk::PipelineDesc pipelineDesc;
     pipelineDesc.initDefaults();
-    pipelineDesc.updateColorWriteMask(colorMaskFlags);
+    pipelineDesc.updateColorWriteMask(colorMaskFlags, getEmulatedAlphaAttachmentMask());
     pipelineDesc.updateRenderPassDesc(getRenderPassDesc());
     pipelineDesc.updateShaders(fullScreenQuad->queueSerial(), pushConstantColor->queueSerial());
     pipelineDesc.updateViewport(renderArea, 0.0f, 1.0f);
@@ -740,10 +760,15 @@ gl::Error FramebufferVk::getCommandBufferForDraw(ContextVk *contextVk,
 
 void FramebufferVk::updateActiveColorMasks(size_t colorIndex, bool r, bool g, bool b, bool a)
 {
-    mActiveColorComponentMasks[0].set(colorIndex, r);
-    mActiveColorComponentMasks[1].set(colorIndex, g);
-    mActiveColorComponentMasks[2].set(colorIndex, b);
-    mActiveColorComponentMasks[3].set(colorIndex, a);
+    mActiveColorComponentMasksForClear[0].set(colorIndex, r);
+    mActiveColorComponentMasksForClear[1].set(colorIndex, g);
+    mActiveColorComponentMasksForClear[2].set(colorIndex, b);
+    mActiveColorComponentMasksForClear[3].set(colorIndex, a);
+}
+
+gl::DrawBufferMask FramebufferVk::getEmulatedAlphaAttachmentMask()
+{
+    return mEmulatedAlphaAttachmentMask;
 }
 
 gl::Error FramebufferVk::readPixelsImpl(const gl::Context *context,

src/libANGLE/renderer/vulkan/FramebufferVk.h

@@ -100,6 +100,8 @@ class FramebufferVk : public FramebufferImpl, public vk::CommandGraphResource
 
     const gl::Extents &getReadImageExtents() const;
 
+    gl::DrawBufferMask getEmulatedAlphaAttachmentMask();
+
   private:
     FramebufferVk(const gl::FramebufferState &state);
     FramebufferVk(const gl::FramebufferState &state, WindowSurfaceVk *backbuffer);
@@ -124,9 +126,13 @@ class FramebufferVk : public FramebufferImpl, public vk::CommandGraphResource
     // channel is masked out, we check against the Framebuffer Attachments (RenderTargets) to see
     // if the masked out channel is present in any of the attachments.
     VkColorComponentFlags mActiveColorComponents;
-    gl::DrawBufferMask mActiveColorComponentMasks[4];
-
+    gl::DrawBufferMask mActiveColorComponentMasksForClear[4];
     vk::DynamicBuffer mReadPixelsBuffer;
+
+    // When we draw to the framebuffer, and the real format has an alpha channel but the format of
+    // the framebuffer does not, we need to mask out the alpha channel. This DrawBufferMask will
+    // contain the mask to apply to the alpha channel when drawing.
+    gl::DrawBufferMask mEmulatedAlphaAttachmentMask;
 };
 }  // namespace rx
 

src/libANGLE/renderer/vulkan/vk_cache_utils.cpp

@@ -723,13 +723,15 @@ void PipelineDesc::updateBlendFuncs(const gl::BlendState &blendState)
     }
 }
 
-void PipelineDesc::updateColorWriteMask(VkColorComponentFlags colorComponentFlags)
+void PipelineDesc::updateColorWriteMask(VkColorComponentFlags colorComponentFlags,
+                                        const gl::DrawBufferMask &alphaMask)
 {
     uint8_t colorMask = static_cast<uint8_t>(colorComponentFlags);
 
-    for (PackedColorBlendAttachmentState &blendAttachmentState : mColorBlendStateInfo.attachments)
+    for (size_t colorIndex = 0; colorIndex < gl::IMPLEMENTATION_MAX_DRAW_BUFFERS; colorIndex++)
     {
-        blendAttachmentState.colorWriteMask = colorMask;
+        mColorBlendStateInfo.attachments[colorIndex].colorWriteMask =
+            alphaMask[colorIndex] ? (colorMask & ~VK_COLOR_COMPONENT_A_BIT) : colorMask;
     }
 }
 

src/libANGLE/renderer/vulkan/vk_cache_utils.h

@@ -382,7 +382,8 @@ class PipelineDesc final
     void updateBlendColor(const gl::ColorF &color);
     void updateBlendFuncs(const gl::BlendState &blendState);
     void updateBlendEquations(const gl::BlendState &blendState);
-    void updateColorWriteMask(VkColorComponentFlags colorComponentFlags);
+    void updateColorWriteMask(VkColorComponentFlags colorComponentFlags,
+                              const gl::DrawBufferMask &alphaMask);
 
     // Depth/stencil states.
     void updateDepthTestEnabled(const gl::DepthStencilState &depthStencilState);

src/tests/deqp_support/deqp_gles2_test_expectations.txt

@@ -231,7 +231,6 @@
 2592 VULKAN : dEQP-GLES2.functional.shaders.builtin_variable.depth_range* = SKIP
 2595 VULKAN : dEQP-GLES2.functional.shaders.random.all_features.fragment* = SKIP
 2597 VULKAN : dEQP-GLES2.functional.fbo.render.recreate_stencilbuffer.no_rebind_rbo_rgb* = SKIP
-2597 VULKAN : dEQP-GLES2.functional.fbo.render.stencil_clear.tex2d_rgb_stencil_index8 = SKIP
 2161 VULKAN : dEQP-GLES2.functional.vertex_arrays.* = SKIP
 2598 VULKAN : dEQP-GLES2.functional.rasterization.primitives.line* = SKIP
 2599 VULKAN : dEQP-GLES2.functional.rasterization.limits.points = SKIP