Vulkan: Implement scissored clears.

src/libANGLE/renderer/vulkan/ContextVk.h

@@ -160,6 +160,7 @@ class ContextVk : public ContextImpl
 
     const VkClearValue &getClearColorValue() const;
     const VkClearValue &getClearDepthStencilValue() const;
+    const VkRect2D &getScissor() const { return mPipelineDesc->getScissor(); }
 
   private:
     gl::Error initPipeline(const gl::Context *context);

src/libANGLE/renderer/vulkan/FramebufferVk.cpp

@@ -136,7 +136,15 @@ gl::Error FramebufferVk::clear(const gl::Context *context, GLbitfield mask)
         return gl::NoError();
     }
 
-    // TODO(jmadill): Scissored clears.
+    if (context->getGLState().isScissorTestEnabled())
+    {
+        // With scissor test enabled, we clear very differently and we don't need to access
+        // the image inside each attachment we can just use clearCmdAttachments with our
+        // scissor region instead.
+        ANGLE_TRY(clearColorAttachmentsWithScissorRegion(context));
+        return gl::NoError();
+    }
+
     const auto *attachment = mState.getFirstNonNullAttachment();
     ASSERT(attachment && attachment->isAttached());
     const auto &size = attachment->getSize();
@@ -461,6 +469,50 @@ gl::ErrorOrResult<vk::Framebuffer *> FramebufferVk::getFramebuffer(const gl::Con
     return &mFramebuffer;
 }
 
+gl::Error FramebufferVk::clearColorAttachmentsWithScissorRegion(const gl::Context *context)
+{
+    ContextVk *contextVk = vk::GetImpl(context);
+    RendererVk *renderer = contextVk->getRenderer();
+
+    // This command can only happen inside a render pass, so obtain one if its already happening
+    // or create a new one if not.
+    vk::CommandGraphNode *node       = nullptr;
+    vk::CommandBuffer *commandBuffer = nullptr;
+    ANGLE_TRY(getCommandGraphNodeForDraw(context, &node));
+    if (node->getInsideRenderPassCommands()->valid())
+    {
+        commandBuffer = node->getInsideRenderPassCommands();
+    }
+    else
+    {
+        ANGLE_TRY(node->beginInsideRenderPassRecording(renderer, &commandBuffer));
+    }
+
+    const std::vector<gl::FramebufferAttachment> &colorAttachments = mState.getColorAttachments();
+    gl::AttachmentArray<VkClearAttachment> clearAttachments;
+    int clearAttachmentIndex = 0;
+    for (auto colorIndex : mState.getEnabledDrawBuffers())
+    {
+        VkClearAttachment &clearAttachment = clearAttachments[clearAttachmentIndex];
+        clearAttachment.aspectMask         = VK_IMAGE_ASPECT_COLOR_BIT;
+        clearAttachment.colorAttachment    = static_cast<uint32_t>(colorIndex);
+        clearAttachment.clearValue         = contextVk->getClearColorValue();
+        ++clearAttachmentIndex;
+    }
+
+    // We assume for now that we always need to clear only 1 layer starting at the
+    // baseArrayLayer 0, this might need to change depending how we'll implement
+    // cube maps, 3d textures and array textures.
+    VkClearRect clearRect;
+    clearRect.baseArrayLayer = 0;
+    clearRect.layerCount     = 1;
+    clearRect.rect           = contextVk->getScissor();
+
+    commandBuffer->clearAttachments(static_cast<uint32_t>(colorAttachments.size()),
+                                    clearAttachments.data(), 1, &clearRect);
+    return gl::NoError();
+}
+
 gl::Error FramebufferVk::getSamplePosition(size_t index, GLfloat *xy) const
 {
     UNIMPLEMENTED();

src/libANGLE/renderer/vulkan/FramebufferVk.h

@@ -95,6 +95,8 @@ class FramebufferVk : public FramebufferImpl, public ResourceVk
     gl::ErrorOrResult<vk::Framebuffer *> getFramebuffer(const gl::Context *context,
                                                         RendererVk *rendererVk);
 
+    gl::Error clearColorAttachmentsWithScissorRegion(const gl::Context *context);
+
     WindowSurfaceVk *mBackbuffer;
 
     Optional<vk::RenderPassDesc> mRenderPassDesc;

src/libANGLE/renderer/vulkan/vk_cache_utils.cpp

@@ -579,7 +579,6 @@ void PipelineDesc::updateViewport(const gl::Rectangle &viewport, float nearPlane
     mViewport.minDepth = nearPlane;
     mViewport.maxDepth = farPlane;
 
-    // TODO(jmadill): Scissor.
     mScissor.offset.x      = viewport.x;
     mScissor.offset.y      = viewport.y;
     mScissor.extent.width  = viewport.width;

src/libANGLE/renderer/vulkan/vk_cache_utils.h

@@ -289,6 +289,7 @@ class PipelineDesc final
     void updateRenderPassDesc(const RenderPassDesc &renderPassDesc);
 
     // Scissor support
+    const VkRect2D &getScissor() const { return mScissor; }
     void updateScissor(const gl::Rectangle &rect);
 
     // Blend states

src/libANGLE/renderer/vulkan/vk_utils.cpp

@@ -514,6 +514,16 @@ void CommandBuffer::clearDepthStencilImage(const vk::Image &image,
                                 rangeCount, ranges);
 }
 
+void CommandBuffer::clearAttachments(uint32_t attachmentCount,
+                                     const VkClearAttachment *attachments,
+                                     uint32_t rectCount,
+                                     const VkClearRect *rects)
+{
+    ASSERT(valid());
+
+    vkCmdClearAttachments(mHandle, attachmentCount, attachments, rectCount, rects);
+}
+
 void CommandBuffer::copySingleImage(const vk::Image &srcImage,
                                     const vk::Image &destImage,
                                     const gl::Box &copyRegion,

src/libANGLE/renderer/vulkan/vk_utils.h

@@ -333,6 +333,7 @@ class CommandBuffer : public WrappedObject<CommandBuffer, VkCommandBuffer>
                              const VkBufferMemoryBarrier &bufferBarrier);
 
     void clearSingleColorImage(const vk::Image &image, const VkClearColorValue &color);
+
     void clearSingleDepthStencilImage(const vk::Image &image,
                                       VkImageAspectFlags aspectFlags,
                                       const VkClearDepthStencilValue &depthStencil);
@@ -342,6 +343,11 @@ class CommandBuffer : public WrappedObject<CommandBuffer, VkCommandBuffer>
                                 uint32_t rangeCount,
                                 const VkImageSubresourceRange *ranges);
 
+    void clearAttachments(uint32_t attachmentCount,
+                          const VkClearAttachment *attachments,
+                          uint32_t rectCount,
+                          const VkClearRect *rects);
+
     void copyBuffer(const vk::Buffer &srcBuffer,
                     const vk::Buffer &destBuffer,
                     uint32_t regionCount,

src/tests/gl_tests/ClearTest.cpp

@@ -434,17 +434,12 @@ class ScissoredClearTest : public ANGLETest
 // Simple scissored clear.
 TEST_P(ScissoredClearTest, BasicScissoredColorClear)
 {
-    // The Vulkan back-end does not implement scissored clears yet.
-    // TODO(jmadill): Enable this when we implement scissored clears in Vulkan.
-    // http://anglebug.com/2356
-    ANGLE_SKIP_TEST_IF(IsVulkan());
-
     const int w     = getWindowWidth();
     const int h     = getWindowHeight();
     const int whalf = w >> 1;
     const int hhalf = h >> 1;
 
-    // Clear who region to red.
+    // Clear whole region to red.
     glClearColor(1.0, 0.0, 0.0, 1.0);
     glClear(GL_COLOR_BUFFER_BIT);