Vulkan: Skip load if depth/stencil value are undefined

src/libANGLE/renderer/vulkan/ContextVk.cpp

@@ -2389,6 +2389,8 @@ void ContextVk::optimizeRenderPassForPresent(VkFramebuffer framebufferHandle)
         // Change depthstencil attachment storeOp to DONT_CARE
         mRenderPassCommands.invalidateRenderPassStencilAttachment(depthStencilAttachmentIndexVk);
         mRenderPassCommands.invalidateRenderPassDepthAttachment(depthStencilAttachmentIndexVk);
+        // Mark content as invalid so that we will not load them in next renderpass
+        depthStencilRenderTarget->invalidateContent();
     }
 
     // Use finalLayout instead of extra barrier for layout change to present

src/libANGLE/renderer/vulkan/FramebufferVk.cpp

@@ -1357,20 +1357,34 @@ angle::Result FramebufferVk::startNewRenderPass(ContextVk *contextVk,
 
         ANGLE_TRY(colorRenderTarget->onColorDraw(contextVk));
 
-        renderPassAttachmentOps.initWithLoadStore(attachmentClearValues.size(),
-                                                  vk::ImageLayout::ColorAttachment,
-                                                  vk::ImageLayout::ColorAttachment);
+        renderPassAttachmentOps.initWithStore(
+            attachmentClearValues.size(), VK_ATTACHMENT_LOAD_OP_LOAD,
+            vk::ImageLayout::ColorAttachment, vk::ImageLayout::ColorAttachment);
         attachmentClearValues.emplace_back(kUninitializedClearValue);
     }
 
     RenderTargetVk *depthStencilRenderTarget = getDepthStencilRenderTarget();
     if (depthStencilRenderTarget)
     {
+        VkAttachmentLoadOp loadOp;
+        if (depthStencilRenderTarget->hasDefinedContent())
+        {
+            loadOp = VK_ATTACHMENT_LOAD_OP_LOAD;
+        }
+        else
+        {
+            loadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
+        }
+        renderPassAttachmentOps.initWithStore(attachmentClearValues.size(), loadOp,
+                                              vk::ImageLayout::DepthStencilAttachment,
+                                              vk::ImageLayout::DepthStencilAttachment);
+
+        // This must be called after hasDefinedContent() since it will set content to valid. We are
+        // tracking content valid very loosely here that as long as it is attached, it assumes will
+        // have valid content. The only time it has undefined content is between swap and
+        // startNewRenderPass
         ANGLE_TRY(depthStencilRenderTarget->onDepthStencilDraw(contextVk));
 
-        renderPassAttachmentOps.initWithLoadStore(attachmentClearValues.size(),
-                                                  vk::ImageLayout::DepthStencilAttachment,
-                                                  vk::ImageLayout::DepthStencilAttachment);
         attachmentClearValues.emplace_back(kUninitializedClearValue);
     }
 

src/libANGLE/renderer/vulkan/RenderTargetVk.cpp

@@ -17,9 +17,11 @@
 
 namespace rx
 {
+
 RenderTargetVk::RenderTargetVk()
-    : mImage(nullptr), mImageViews(nullptr), mLevelIndex(0), mLayerIndex(0)
-{}
+{
+    reset();
+}
 
 RenderTargetVk::~RenderTargetVk() {}
 
@@ -27,12 +29,10 @@ RenderTargetVk::RenderTargetVk(RenderTargetVk &&other)
     : mImage(other.mImage),
       mImageViews(other.mImageViews),
       mLevelIndex(other.mLevelIndex),
-      mLayerIndex(other.mLayerIndex)
+      mLayerIndex(other.mLayerIndex),
+      mContentDefined(other.mContentDefined)
 {
-    other.mImage      = nullptr;
-    other.mImageViews = nullptr;
-    other.mLevelIndex = 0;
-    other.mLayerIndex = 0;
+    other.reset();
 }
 
 void RenderTargetVk::init(vk::ImageHelper *image,
@@ -44,14 +44,18 @@ void RenderTargetVk::init(vk::ImageHelper *image,
     mImageViews = imageViews;
     mLevelIndex = levelIndex;
     mLayerIndex = layerIndex;
+    // We are being conservative here since our targeted optimization is to skip surfaceVK's depth
+    // buffer load after swap call.
+    mContentDefined = true;
 }
 
 void RenderTargetVk::reset()
 {
-    mImage      = nullptr;
-    mImageViews = nullptr;
-    mLevelIndex = 0;
-    mLayerIndex = 0;
+    mImage          = nullptr;
+    mImageViews     = nullptr;
+    mLevelIndex     = 0;
+    mLayerIndex     = 0;
+    mContentDefined = false;
 }
 
 vk::AttachmentSerial RenderTargetVk::getAssignSerial(ContextVk *contextVk)
@@ -74,6 +78,7 @@ angle::Result RenderTargetVk::onColorDraw(ContextVk *contextVk)
 
     contextVk->onRenderPassImageWrite(VK_IMAGE_ASPECT_COLOR_BIT, vk::ImageLayout::ColorAttachment,
                                       mImage);
+    mContentDefined = true;
     retainImageViews(contextVk);
 
     return angle::Result::Continue;
@@ -87,6 +92,7 @@ angle::Result RenderTargetVk::onDepthStencilDraw(ContextVk *contextVk)
     VkImageAspectFlags aspectFlags = vk::GetDepthStencilAspectFlags(format);
 
     contextVk->onRenderPassImageWrite(aspectFlags, vk::ImageLayout::DepthStencilAttachment, mImage);
+    mContentDefined = true;
     retainImageViews(contextVk);
 
     return angle::Result::Continue;

src/libANGLE/renderer/vulkan/RenderTargetVk.h

@@ -77,11 +77,18 @@ class RenderTargetVk final : public FramebufferAttachmentRenderTarget
 
     void retainImageViews(ContextVk *contextVk) const;
 
+    bool hasDefinedContent() const { return mContentDefined; }
+    // mark content as undefined so that certain optimizations are possible
+    void invalidateContent() { mContentDefined = false; }
+
   private:
     vk::ImageHelper *mImage;
     vk::ImageViewHelper *mImageViews;
     uint32_t mLevelIndex;
     uint32_t mLayerIndex;
+    // Right now we are only tracking depth/stencil buffer. We could expand it to cover color
+    // buffers if needed in future.
+    bool mContentDefined;
 };
 
 // A vector of rendertargets

src/libANGLE/renderer/vulkan/UtilsVk.cpp

@@ -1189,8 +1189,9 @@ angle::Result UtilsVk::startRenderPass(ContextVk *contextVk,
     std::vector<VkClearValue> clearValues = {{}};
     ASSERT(clearValues.size() == 1);
 
-    renderPassAttachmentOps.initWithLoadStore(0, vk::ImageLayout::ColorAttachment,
-                                              vk::ImageLayout::ColorAttachment);
+    renderPassAttachmentOps.initWithStore(0, VK_ATTACHMENT_LOAD_OP_LOAD,
+                                          vk::ImageLayout::ColorAttachment,
+                                          vk::ImageLayout::ColorAttachment);
 
     ANGLE_TRY(contextVk->flushAndBeginRenderPass(framebuffer, renderArea, renderPassDesc,
                                                  renderPassAttachmentOps, clearValues,

src/libANGLE/renderer/vulkan/vk_cache_utils.cpp

@@ -1456,16 +1456,17 @@ void AttachmentOpsArray::initDummyOp(size_t index,
     SetBitField(ops.stencilStoreOp, VK_ATTACHMENT_STORE_OP_DONT_CARE);
 }
 
-void AttachmentOpsArray::initWithLoadStore(size_t index,
-                                           ImageLayout initialLayout,
-                                           ImageLayout finalLayout)
+void AttachmentOpsArray::initWithStore(size_t index,
+                                       VkAttachmentLoadOp loadOp,
+                                       ImageLayout initialLayout,
+                                       ImageLayout finalLayout)
 {
     PackedAttachmentOpsDesc &ops = mOps[index];
 
     SetBitField(ops.initialLayout, initialLayout);
     SetBitField(ops.finalLayout, finalLayout);
-    SetBitField(ops.loadOp, VK_ATTACHMENT_LOAD_OP_LOAD);
-    SetBitField(ops.stencilLoadOp, VK_ATTACHMENT_LOAD_OP_LOAD);
+    SetBitField(ops.loadOp, loadOp);
+    SetBitField(ops.stencilLoadOp, loadOp);
     SetBitField(ops.storeOp, VK_ATTACHMENT_STORE_OP_STORE);
     SetBitField(ops.stencilStoreOp, VK_ATTACHMENT_STORE_OP_STORE);
 }

src/libANGLE/renderer/vulkan/vk_cache_utils.h

@@ -154,8 +154,11 @@ class AttachmentOpsArray final
 
     // Initializes an attachment op with whatever values. Used for compatible RenderPass checks.
     void initDummyOp(size_t index, ImageLayout initialLayout, ImageLayout finalLayout);
-    // Initialize an attachment op with all load and store operations.
-    void initWithLoadStore(size_t index, ImageLayout initialLayout, ImageLayout finalLayout);
+    // Initialize an attachment op with store operations.
+    void initWithStore(size_t index,
+                       VkAttachmentLoadOp loadOp,
+                       ImageLayout initialLayout,
+                       ImageLayout finalLayout);
 
     size_t hash() const;