[Impeller] Cache RenderPass/Framebuffer objects on the resolve texture sources. (flutter/engine#50142)

Cache vk::RenderPass and vk::Framebuffer objects on the resolve texture of any render target attachments. Use these on the next frame unconditionally.

Fixes https://github.com/flutter/flutter/issues/141750

engine/src/flutter/ci/licenses_golden/excluded_files

@@ -176,6 +176,7 @@
 ../../../flutter/impeller/renderer/backend/vulkan/context_vk_unittests.cc
 ../../../flutter/impeller/renderer/backend/vulkan/descriptor_pool_vk_unittests.cc
 ../../../flutter/impeller/renderer/backend/vulkan/fence_waiter_vk_unittests.cc
+../../../flutter/impeller/renderer/backend/vulkan/render_pass_cache_unittests.cc
 ../../../flutter/impeller/renderer/backend/vulkan/resource_manager_vk_unittests.cc
 ../../../flutter/impeller/renderer/backend/vulkan/test
 ../../../flutter/impeller/renderer/blit_pass_unittests.cc

engine/src/flutter/impeller/renderer/backend/vulkan/BUILD.gn

@@ -14,6 +14,7 @@ impeller_component("vulkan_unittests") {
     "context_vk_unittests.cc",
     "descriptor_pool_vk_unittests.cc",
     "fence_waiter_vk_unittests.cc",
+    "render_pass_cache_unittests.cc",
     "resource_manager_vk_unittests.cc",
     "test/gpu_tracer_unittests.cc",
     "test/mock_vulkan.cc",
@@ -23,6 +24,7 @@ impeller_component("vulkan_unittests") {
   ]
   deps = [
     ":vulkan",
+    "../../../playground:playground_test",
     "//flutter/testing:testing_lib",
   ]
 }

engine/src/flutter/impeller/renderer/backend/vulkan/render_pass_cache_unittests.cc

@@ -0,0 +1,51 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/testing/testing.h"
+#include "gtest/gtest.h"
+#include "impeller/playground/playground_test.h"
+#include "impeller/renderer/backend/vulkan/texture_vk.h"
+#include "impeller/renderer/render_target.h"
+
+namespace impeller {
+namespace testing {
+
+using RendererTest = PlaygroundTest;
+
+TEST_P(RendererTest, CachesRenderPassAndFramebuffer) {
+  if (GetBackend() != PlaygroundBackend::kVulkan) {
+    GTEST_SKIP() << "Test only applies to Vulkan";
+  }
+
+  auto allocator = std::make_shared<RenderTargetAllocator>(
+      GetContext()->GetResourceAllocator());
+
+  auto render_target = RenderTarget::CreateOffscreenMSAA(
+      *GetContext(), *allocator, {100, 100}, 1);
+  auto resolve_texture =
+      render_target.GetColorAttachments().find(0u)->second.resolve_texture;
+  auto& texture_vk = TextureVK::Cast(*resolve_texture);
+
+  EXPECT_EQ(texture_vk.GetFramebuffer(), nullptr);
+  EXPECT_EQ(texture_vk.GetRenderPass(), nullptr);
+
+  auto buffer = GetContext()->CreateCommandBuffer();
+  auto render_pass = buffer->CreateRenderPass(render_target);
+
+  EXPECT_NE(texture_vk.GetFramebuffer(), nullptr);
+  EXPECT_NE(texture_vk.GetRenderPass(), nullptr);
+
+  render_pass->EncodeCommands();
+  GetContext()->GetCommandQueue()->Submit({buffer});
+
+  // Can be reused without error.
+  auto buffer_2 = GetContext()->CreateCommandBuffer();
+  auto render_pass_2 = buffer_2->CreateRenderPass(render_target);
+
+  EXPECT_TRUE(render_pass_2->EncodeCommands());
+  EXPECT_TRUE(GetContext()->GetCommandQueue()->Submit({buffer_2}).ok());
+}
+
+}  // namespace testing
+}  // namespace impeller

engine/src/flutter/impeller/renderer/backend/vulkan/render_pass_vk.cc

@@ -25,6 +25,7 @@
 #include "impeller/renderer/backend/vulkan/shared_object_vk.h"
 #include "impeller/renderer/backend/vulkan/texture_vk.h"
 #include "impeller/renderer/backend/vulkan/vk.h"
+#include "vulkan/vulkan_handles.hpp"
 
 namespace impeller {
 
@@ -79,6 +80,7 @@ static std::vector<vk::ClearValue> GetVKClearValues(
 
 SharedHandleVK<vk::RenderPass> RenderPassVK::CreateVKRenderPass(
     const ContextVK& context,
+    const SharedHandleVK<vk::RenderPass>& recycled_renderpass,
     const std::shared_ptr<CommandBufferVK>& command_buffer) const {
   BarrierVK barrier;
   barrier.new_layout = vk::ImageLayout::eGeneral;
@@ -127,6 +129,15 @@ SharedHandleVK<vk::RenderPass> RenderPassVK::CreateVKRenderPass(
     TextureVK::Cast(*stencil->texture).SetLayout(barrier);
   }
 
+  // There may exist a previous recycled render pass that we can continue using.
+  // This is probably compatible with the render pass we are about to construct,
+  // but I have not conclusively proven this. If there are scenarios that
+  // produce validation warnings, we could use them to determine if we need
+  // additional checks at this point to determine reusability.
+  if (recycled_renderpass != nullptr) {
+    return recycled_renderpass;
+  }
+
   auto pass = builder.Build(context.GetDevice());
 
   if (!pass) {
@@ -143,6 +154,11 @@ RenderPassVK::RenderPassVK(const std::shared_ptr<const Context>& context,
                            const RenderTarget& target,
                            std::shared_ptr<CommandBufferVK> command_buffer)
     : RenderPass(context, target), command_buffer_(std::move(command_buffer)) {
+  color_image_vk_ =
+      render_target_.GetColorAttachments().find(0u)->second.texture;
+  resolve_image_vk_ =
+      render_target_.GetColorAttachments().find(0u)->second.resolve_texture;
+
   const auto& vk_context = ContextVK::Cast(*context);
   const std::shared_ptr<CommandEncoderVK>& encoder =
       command_buffer_->GetEncoder();
@@ -154,16 +170,26 @@ RenderPassVK::RenderPassVK(const std::shared_ptr<const Context>& context,
         return true;
       });
 
+  SharedHandleVK<vk::RenderPass> recycled_render_pass;
+  SharedHandleVK<vk::Framebuffer> recycled_framebuffer;
+  if (resolve_image_vk_) {
+    recycled_render_pass = TextureVK::Cast(*resolve_image_vk_).GetRenderPass();
+    recycled_framebuffer = TextureVK::Cast(*resolve_image_vk_).GetFramebuffer();
+  }
+
   const auto& target_size = render_target_.GetRenderTargetSize();
 
-  render_pass_ = CreateVKRenderPass(vk_context, command_buffer_);
+  render_pass_ =
+      CreateVKRenderPass(vk_context, recycled_render_pass, command_buffer_);
   if (!render_pass_) {
     VALIDATION_LOG << "Could not create renderpass.";
     is_valid_ = false;
     return;
   }
 
-  auto framebuffer = CreateVKFramebuffer(vk_context, *render_pass_);
+  auto framebuffer = (recycled_framebuffer == nullptr)
+                         ? CreateVKFramebuffer(vk_context, *render_pass_)
+                         : recycled_framebuffer;
   if (!framebuffer) {
     VALIDATION_LOG << "Could not create framebuffer.";
     is_valid_ = false;
@@ -174,6 +200,10 @@ RenderPassVK::RenderPassVK(const std::shared_ptr<const Context>& context,
     is_valid_ = false;
     return;
   }
+  if (resolve_image_vk_) {
+    TextureVK::Cast(*resolve_image_vk_).SetFramebuffer(framebuffer);
+    TextureVK::Cast(*resolve_image_vk_).SetRenderPass(render_pass_);
+  }
 
   auto clear_values = GetVKClearValues(render_target_);
 
@@ -205,10 +235,6 @@ RenderPassVK::RenderPassVK(const std::shared_ptr<const Context>& context,
           .setExtent(vk::Extent2D(sc.GetWidth(), sc.GetHeight()));
   command_buffer_vk_.setScissor(0, 1, &scissor);
 
-  color_image_vk_ =
-      render_target_.GetColorAttachments().find(0u)->second.texture;
-  resolve_image_vk_ =
-      render_target_.GetColorAttachments().find(0u)->second.resolve_texture;
   is_valid_ = true;
 }
 

engine/src/flutter/impeller/renderer/backend/vulkan/render_pass_vk.h

@@ -11,6 +11,7 @@
 #include "impeller/renderer/backend/vulkan/shared_object_vk.h"
 #include "impeller/renderer/render_pass.h"
 #include "impeller/renderer/render_target.h"
+#include "vulkan/vulkan_handles.hpp"
 
 namespace impeller {
 
@@ -123,6 +124,7 @@ class RenderPassVK final : public RenderPass {
 
   SharedHandleVK<vk::RenderPass> CreateVKRenderPass(
       const ContextVK& context,
+      const SharedHandleVK<vk::RenderPass>& recycled_renderpass,
       const std::shared_ptr<CommandBufferVK>& command_buffer) const;
 
   SharedHandleVK<vk::Framebuffer> CreateVKFramebuffer(

engine/src/flutter/impeller/renderer/backend/vulkan/swapchain_image_vk.h

@@ -9,6 +9,7 @@
 #include "impeller/renderer/backend/vulkan/formats_vk.h"
 #include "impeller/renderer/backend/vulkan/texture_source_vk.h"
 #include "impeller/renderer/backend/vulkan/vk.h"
+#include "vulkan/vulkan_handles.hpp"
 
 namespace impeller {
 

engine/src/flutter/impeller/renderer/backend/vulkan/texture_source_vk.h

@@ -10,7 +10,9 @@
 #include "impeller/core/texture_descriptor.h"
 #include "impeller/renderer/backend/vulkan/barrier_vk.h"
 #include "impeller/renderer/backend/vulkan/formats_vk.h"
+#include "impeller/renderer/backend/vulkan/shared_object_vk.h"
 #include "impeller/renderer/backend/vulkan/vk.h"
+#include "vulkan/vulkan_handles.hpp"
 
 namespace impeller {
 

engine/src/flutter/impeller/renderer/backend/vulkan/texture_vk.cc

@@ -173,4 +173,22 @@ vk::ImageView TextureVK::GetRenderTargetView() const {
   return source_->GetRenderTargetView();
 }
 
+void TextureVK::SetFramebuffer(
+    const SharedHandleVK<vk::Framebuffer>& framebuffer) {
+  framebuffer_ = framebuffer;
+}
+
+void TextureVK::SetRenderPass(
+    const SharedHandleVK<vk::RenderPass>& render_pass) {
+  render_pass_ = render_pass;
+}
+
+SharedHandleVK<vk::Framebuffer> TextureVK::GetFramebuffer() const {
+  return framebuffer_;
+}
+
+SharedHandleVK<vk::RenderPass> TextureVK::GetRenderPass() const {
+  return render_pass_;
+}
+
 }  // namespace impeller

engine/src/flutter/impeller/renderer/backend/vulkan/texture_vk.h

@@ -44,9 +44,37 @@ class TextureVK final : public Texture, public BackendCast<TextureVK, Texture> {
 
   bool IsSwapchainImage() const { return source_->IsSwapchainImage(); }
 
+  // These methods should only be used by render_pass_vk.h
+
+  /// Store the last framebuffer object used with this texture.
+  ///
+  /// This field is only set if this texture is used as the resolve texture
+  /// of a render pass. By construction, this framebuffer should be compatible
+  /// with any future render passes.
+  void SetFramebuffer(const SharedHandleVK<vk::Framebuffer>& framebuffer);
+
+  /// Store the last render pass object used with this texture.
+  ///
+  /// This field is only set if this texture is used as the resolve texture
+  /// of a render pass. By construction, this framebuffer should be compatible
+  /// with any future render passes.
+  void SetRenderPass(const SharedHandleVK<vk::RenderPass>& render_pass);
+
+  /// Retrieve the last framebuffer object used with this texture.
+  ///
+  /// May be nullptr if no previous framebuffer existed.
+  SharedHandleVK<vk::Framebuffer> GetFramebuffer() const;
+
+  /// Retrieve the last render pass object used with this texture.
+  ///
+  /// May be nullptr if no previous render pass existed.
+  SharedHandleVK<vk::RenderPass> GetRenderPass() const;
+
  private:
   std::weak_ptr<Context> context_;
   std::shared_ptr<TextureSourceVK> source_;
+  SharedHandleVK<vk::Framebuffer> framebuffer_ = nullptr;
+  SharedHandleVK<vk::RenderPass> render_pass_ = nullptr;
 
   // |Texture|
   void SetLabel(std::string_view label) override;