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

ci/licenses_golden/excluded_files

@@ -136,6 +136,7 @@
 ../../../flutter/impeller/docs
 ../../../flutter/impeller/entity/contents/checkerboard_contents_unittests.cc
 ../../../flutter/impeller/entity/contents/filters/inputs/filter_input_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

@@ -270,10 +270,12 @@ impeller_component("entity_unittests") {
   sources = [
     "contents/checkerboard_contents_unittests.cc",
     "contents/filters/inputs/filter_input_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 = [
@@ -283,14 +285,3 @@ 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

@@ -397,7 +397,10 @@ 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()) {

impeller/entity/entity_pass_target.cc

@@ -45,7 +45,16 @@ 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 (color0.resolve_texture == color0.texture) {
+    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_unittests.cc

@@ -0,0 +1,88 @@
+// 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/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);
+
+  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) {
+  if (!GetContentContext()
+           ->GetDeviceCapabilities()
+           .SupportsImplicitResolvingMSAA()) {
+    GTEST_SKIP() << "Implicit MSAA is not 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);
+
+  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_EQ(msaa_tex, color0.texture);
+  ASSERT_NE(resolve_tex, color0.resolve_texture);
+  ASSERT_TRUE(false);  // see if this runs.
+}
+
+}  // namespace testing
+}  // namespace impeller