[Impeller] Fix EntityPassTarget::Flip with implict MSAA.

ci/licenses_golden/excluded_files

@@ -138,6 +138,7 @@
 ../../../flutter/impeller/entity/contents/filters/inputs/filter_input_unittests.cc
 ../../../flutter/impeller/entity/contents/test
 ../../../flutter/impeller/entity/contents/vertices_contents_unittests.cc
+../../../flutter/impeller/entity/entity_pass_target_unittests.cc
 ../../../flutter/impeller/entity/entity_unittests.cc
 ../../../flutter/impeller/entity/geometry/geometry_unittests.cc
 ../../../flutter/impeller/entity/render_target_cache_unittests.cc

impeller/BUILD.gn

@@ -98,7 +98,6 @@ impeller_component("impeller_unittests") {
       "aiks:aiks_unittests",
       "display_list:display_list_unittests",
       "entity:entity_unittests",
-      "entity:render_target_cache_unittests",
       "fixtures",
       "geometry:geometry_unittests",
       "image:image_unittests",

impeller/core/texture.h

@@ -6,7 +6,6 @@
 
 #include <string_view>
 
-#include "flutter/fml/macros.h"
 #include "flutter/fml/mapping.h"
 #include "impeller/core/formats.h"
 #include "impeller/core/texture_descriptor.h"

impeller/entity/BUILD.gn

@@ -282,10 +282,12 @@ impeller_component("entity_unittests") {
     "contents/checkerboard_contents_unittests.cc",
     "contents/filters/inputs/filter_input_unittests.cc",
     "contents/vertices_contents_unittests.cc",
+    "entity_pass_target_unittests.cc",
     "entity_playground.cc",
     "entity_playground.h",
     "entity_unittests.cc",
     "geometry/geometry_unittests.cc",
+    "render_target_cache_unittests.cc",
   ]
 
   deps = [
@@ -296,14 +298,3 @@ impeller_component("entity_unittests") {
     "//flutter/impeller/typographer/backends/skia:typographer_skia_backend",
   ]
 }
-
-impeller_component("render_target_cache_unittests") {
-  testonly = true
-
-  sources = [ "render_target_cache_unittests.cc" ]
-
-  deps = [
-    ":entity",
-    "//flutter/testing:testing_lib",
-  ]
-}

impeller/entity/entity_pass.cc

@@ -286,7 +286,8 @@ static EntityPassTarget CreateRenderTarget(ContentContext& renderer,
   }
 
   return EntityPassTarget(
-      target, renderer.GetDeviceCapabilities().SupportsReadFromResolve());
+      target, renderer.GetDeviceCapabilities().SupportsReadFromResolve(),
+      renderer.GetDeviceCapabilities().SupportsImplicitResolvingMSAA());
 }
 
 uint32_t EntityPass::GetTotalPassReads(ContentContext& renderer) const {
@@ -397,7 +398,10 @@ bool EntityPass::Render(ContentContext& renderer,
         entity.SetContents(contents);
         entity.SetBlendMode(BlendMode::kSource);
 
-        entity.Render(renderer, *render_pass);
+        if (!entity.Render(renderer, *render_pass)) {
+          VALIDATION_LOG << "Failed to render EntityPass root blit.";
+          return false;
+        }
       }
 
       if (!render_pass->EncodeCommands()) {
@@ -455,7 +459,8 @@ bool EntityPass::Render(ContentContext& renderer,
 
   EntityPassTarget pass_target(
       root_render_target,
-      renderer.GetDeviceCapabilities().SupportsReadFromResolve());
+      renderer.GetDeviceCapabilities().SupportsReadFromResolve(),
+      renderer.GetDeviceCapabilities().SupportsImplicitResolvingMSAA());
 
   return OnRender(                               //
       renderer,                                  // renderer

impeller/entity/entity_pass_target.cc

@@ -11,9 +11,11 @@
 namespace impeller {
 
 EntityPassTarget::EntityPassTarget(const RenderTarget& render_target,
-                                   bool supports_read_from_resolve)
+                                   bool supports_read_from_resolve,
+                                   bool supports_implicit_msaa)
     : target_(render_target),
-      supports_read_from_resolve_(supports_read_from_resolve) {}
+      supports_read_from_resolve_(supports_read_from_resolve),
+      supports_implicit_msaa_(supports_implicit_msaa) {}
 
 std::shared_ptr<Texture> EntityPassTarget::Flip(Allocator& allocator) {
   auto color0 = target_.GetColorAttachments().find(0)->second;
@@ -45,7 +47,16 @@ std::shared_ptr<Texture> EntityPassTarget::Flip(Allocator& allocator) {
     }
   }
 
-  std::swap(color0.resolve_texture, secondary_color_texture_);
+  // If the color0 resolve texture is the same as the texture, then we're
+  // running on the GLES backend with implicit resolve.
+  if (supports_implicit_msaa_) {
+    auto new_secondary = color0.resolve_texture;
+    color0.resolve_texture = secondary_color_texture_;
+    color0.texture = secondary_color_texture_;
+    secondary_color_texture_ = new_secondary;
+  } else {
+    std::swap(color0.resolve_texture, secondary_color_texture_);
+  }
 
   target_.SetColorAttachment(color0, 0);
 

impeller/entity/entity_pass_target.h

@@ -14,7 +14,8 @@ class InlinePassContext;
 class EntityPassTarget {
  public:
   explicit EntityPassTarget(const RenderTarget& render_target,
-                            bool supports_read_from_resolve);
+                            bool supports_read_from_resolve,
+                            bool supports_implicit_msaa);
 
   /// @brief  Flips the backdrop and returns a readable texture that can be
   ///         bound/sampled to restore the previous pass.
@@ -34,6 +35,7 @@ class EntityPassTarget {
   std::shared_ptr<Texture> secondary_color_texture_;
 
   bool supports_read_from_resolve_;
+  bool supports_implicit_msaa_;
 
   friend InlinePassContext;
 

impeller/entity/entity_pass_target_unittests.cc

@@ -0,0 +1,114 @@
+// 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 <memory>
+
+#include "flutter/testing/testing.h"
+#include "gtest/gtest.h"
+#include "impeller/core/formats.h"
+#include "impeller/entity/entity_pass_target.h"
+#include "impeller/entity/entity_playground.h"
+
+namespace impeller {
+namespace testing {
+
+using EntityPassTargetTest = EntityPlayground;
+INSTANTIATE_PLAYGROUND_SUITE(EntityPassTargetTest);
+
+TEST_P(EntityPassTargetTest, SwapWithMSAATexture) {
+  if (GetContentContext()
+          ->GetDeviceCapabilities()
+          .SupportsImplicitResolvingMSAA()) {
+    GTEST_SKIP() << "Implicit MSAA is used on this device.";
+  }
+  auto content_context = GetContentContext();
+  auto buffer = content_context->GetContext()->CreateCommandBuffer();
+  auto render_target = RenderTarget::CreateOffscreenMSAA(
+      *content_context->GetContext(),
+      *GetContentContext()->GetRenderTargetCache(), {100, 100});
+
+  auto entity_pass_target = EntityPassTarget(render_target, false, false);
+
+  auto color0 = entity_pass_target.GetRenderTarget()
+                    .GetColorAttachments()
+                    .find(0u)
+                    ->second;
+  auto msaa_tex = color0.texture;
+  auto resolve_tex = color0.resolve_texture;
+
+  entity_pass_target.Flip(
+      *content_context->GetContext()->GetResourceAllocator());
+
+  color0 = entity_pass_target.GetRenderTarget()
+               .GetColorAttachments()
+               .find(0u)
+               ->second;
+
+  ASSERT_EQ(msaa_tex, color0.texture);
+  ASSERT_NE(resolve_tex, color0.resolve_texture);
+}
+
+TEST_P(EntityPassTargetTest, SwapWithMSAAImplicitResolve) {
+  auto content_context = GetContentContext();
+  auto buffer = content_context->GetContext()->CreateCommandBuffer();
+  auto context = content_context->GetContext();
+  auto& allocator = *context->GetResourceAllocator();
+
+  // Emulate implicit MSAA resolve by making color resolve and msaa texture the
+  // same.
+  RenderTarget render_target;
+  {
+    PixelFormat pixel_format =
+        context->GetCapabilities()->GetDefaultColorFormat();
+
+    // Create MSAA color texture.
+
+    TextureDescriptor color0_tex_desc;
+    color0_tex_desc.storage_mode = StorageMode::kDevicePrivate;
+    color0_tex_desc.type = TextureType::kTexture2DMultisample;
+    color0_tex_desc.sample_count = SampleCount::kCount4;
+    color0_tex_desc.format = pixel_format;
+    color0_tex_desc.size = ISize{100, 100};
+    color0_tex_desc.usage = static_cast<uint64_t>(TextureUsage::kRenderTarget);
+
+    auto color0_msaa_tex = allocator.CreateTexture(color0_tex_desc);
+
+    // Color attachment.
+
+    ColorAttachment color0;
+    color0.load_action = LoadAction::kDontCare;
+    color0.store_action = StoreAction::kStoreAndMultisampleResolve;
+    color0.texture = color0_msaa_tex;
+    color0.resolve_texture = color0_msaa_tex;
+
+    render_target.SetColorAttachment(color0, 0u);
+    render_target.SetStencilAttachment(std::nullopt);
+  }
+
+  auto entity_pass_target = EntityPassTarget(render_target, false, true);
+
+  auto color0 = entity_pass_target.GetRenderTarget()
+                    .GetColorAttachments()
+                    .find(0u)
+                    ->second;
+  auto msaa_tex = color0.texture;
+  auto resolve_tex = color0.resolve_texture;
+
+  ASSERT_EQ(msaa_tex, resolve_tex);
+
+  entity_pass_target.Flip(
+      *content_context->GetContext()->GetResourceAllocator());
+
+  color0 = entity_pass_target.GetRenderTarget()
+               .GetColorAttachments()
+               .find(0u)
+               ->second;
+
+  ASSERT_NE(msaa_tex, color0.texture);
+  ASSERT_NE(resolve_tex, color0.resolve_texture);
+  ASSERT_EQ(color0.texture, color0.resolve_texture);
+}
+
+}  // namespace testing
+}  // namespace impeller