[Impeller] Allow image rasterization/decoding before/without surface acquisition

flow/surface.cc

@@ -26,7 +26,7 @@ bool Surface::EnableRasterCache() const {
   return true;
 }
 
-impeller::AiksContext* Surface::GetAiksContext() const {
+std::shared_ptr<impeller::AiksContext> Surface::GetAiksContext() const {
   return nullptr;
 }
 

flow/surface.h

@@ -49,7 +49,7 @@ class Surface {
 
   virtual bool EnableRasterCache() const;
 
-  virtual impeller::AiksContext* GetAiksContext() const;
+  virtual std::shared_ptr<impeller::AiksContext> GetAiksContext() const;
 
   /// Capture the `SurfaceData` currently present in the surface.
   ///

shell/common/rasterizer.cc

@@ -53,6 +53,11 @@ fml::TaskRunnerAffineWeakPtr<SnapshotDelegate> Rasterizer::GetSnapshotDelegate()
   return weak_factory_.GetWeakPtr();
 }
 
+void Rasterizer::SetImpellerContext(
+    std::weak_ptr<impeller::Context> impeller_context) {
+  impeller_context_ = std::move(impeller_context);
+}
+
 void Rasterizer::Setup(std::unique_ptr<Surface> surface) {
   surface_ = std::move(surface);
 
@@ -544,7 +549,7 @@ RasterStatus Rasterizer::DrawToSurfaceUnsafe(
           .supports_readback,                // surface supports pixel reads
       raster_thread_merger_,                 // thread merger
       frame->GetDisplayListBuilder().get(),  // display list builder
-      surface_->GetAiksContext()             // aiks context
+      surface_->GetAiksContext().get()       // aiks context
   );
   if (compositor_frame) {
     compositor_context_->raster_cache().BeginFrame();

shell/common/rasterizer.h

@@ -23,6 +23,11 @@
 #include "flutter/fml/synchronization/waitable_event.h"
 #include "flutter/fml/time/time_delta.h"
 #include "flutter/fml/time/time_point.h"
+#if IMPELLER_SUPPORTS_RENDERING
+// GN is having trouble understanding how this works in the Fuchsia builds.
+#include "flutter/impeller/aiks/aiks_context.h"  // nogncheck
+#include "flutter/impeller/renderer/context.h"   // nogncheck
+#endif                                           // IMPELLER_SUPPORTS_RENDERING
 #include "flutter/lib/ui/snapshot_delegate.h"
 #include "flutter/shell/common/pipeline.h"
 #include "flutter/shell/common/snapshot_controller.h"
@@ -33,6 +38,13 @@
 #include "third_party/skia/include/core/SkRefCnt.h"
 #include "third_party/skia/include/gpu/GrDirectContext.h"
 
+#if !IMPELLER_SUPPORTS_RENDERING
+namespace impeller {
+class Context;
+class AiksContext;
+}  // namespace impeller
+#endif  // !IMPELLER_SUPPORTS_RENDERING
+
 namespace flutter {
 
 //------------------------------------------------------------------------------
@@ -140,6 +152,8 @@ class Rasterizer final : public SnapshotDelegate,
   ///
   ~Rasterizer();
 
+  void SetImpellerContext(std::weak_ptr<impeller::Context> impeller_context);
+
   //----------------------------------------------------------------------------
   /// @brief      Rasterizers may be created well before an on-screen surface is
   ///             available for rendering. Shells usually create a rasterizer in
@@ -509,6 +523,19 @@ class Rasterizer final : public SnapshotDelegate,
     return surface_;
   }
 
+  // |SnapshotController::Delegate|
+  std::shared_ptr<impeller::AiksContext> GetAiksContext() const override {
+#if IMPELLER_SUPPORTS_RENDERING
+    if (surface_) {
+      return surface_->GetAiksContext();
+    }
+    if (auto context = impeller_context_.lock()) {
+      return std::make_shared<impeller::AiksContext>(context);
+    }
+#endif
+    return nullptr;
+  }
+
   // |SnapshotController::Delegate|
   const std::unique_ptr<SnapshotSurfaceProducer>& GetSnapshotSurfaceProducer()
       const override {
@@ -544,6 +571,7 @@ class Rasterizer final : public SnapshotDelegate,
 
   Delegate& delegate_;
   MakeGpuImageBehavior gpu_image_behavior_;
+  std::weak_ptr<impeller::Context> impeller_context_;
   std::unique_ptr<Surface> surface_;
   std::unique_ptr<SnapshotSurfaceProducer> snapshot_surface_producer_;
   std::unique_ptr<flutter::CompositorContext> compositor_context_;

shell/common/shell.cc

@@ -186,30 +186,33 @@ std::unique_ptr<Shell> Shell::CreateShellOnPlatformThread(
                     !settings.skia_deterministic_rendering_on_cpu),
                 is_gpu_disabled));
 
+  // Create the platform view on the platform thread (this thread).
+  auto platform_view = on_create_platform_view(*shell.get());
+  if (!platform_view || !platform_view->GetWeakPtr()) {
+    return nullptr;
+  }
+
   // Create the rasterizer on the raster thread.
   std::promise<std::unique_ptr<Rasterizer>> rasterizer_promise;
   auto rasterizer_future = rasterizer_promise.get_future();
   std::promise<fml::TaskRunnerAffineWeakPtr<SnapshotDelegate>>
       snapshot_delegate_promise;
   auto snapshot_delegate_future = snapshot_delegate_promise.get_future();
   fml::TaskRunner::RunNowOrPostTask(
-      task_runners.GetRasterTaskRunner(), [&rasterizer_promise,  //
-                                           &snapshot_delegate_promise,
-                                           on_create_rasterizer,  //
-                                           shell = shell.get()    //
+      task_runners.GetRasterTaskRunner(),
+      [&rasterizer_promise,  //
+       &snapshot_delegate_promise,
+       on_create_rasterizer,                                   //
+       shell = shell.get(),                                    //
+       impeller_context = platform_view->GetImpellerContext()  //
   ]() {
         TRACE_EVENT0("flutter", "ShellSetupGPUSubsystem");
         std::unique_ptr<Rasterizer> rasterizer(on_create_rasterizer(*shell));
+        rasterizer->SetImpellerContext(impeller_context);
         snapshot_delegate_promise.set_value(rasterizer->GetSnapshotDelegate());
         rasterizer_promise.set_value(std::move(rasterizer));
       });
 
-  // Create the platform view on the platform thread (this thread).
-  auto platform_view = on_create_platform_view(*shell.get());
-  if (!platform_view || !platform_view->GetWeakPtr()) {
-    return nullptr;
-  }
-
   // Ask the platform view for the vsync waiter. This will be used by the engine
   // to create the animator.
   auto vsync_waiter = platform_view->CreateVSyncWaiter();

shell/common/shell_test_platform_view_metal.h

@@ -49,6 +49,9 @@ class ShellTestPlatformViewMetal final : public ShellTestPlatformView,
   // |PlatformView|
   std::unique_ptr<Surface> CreateRenderingSurface() override;
 
+  // |PlatformView|
+  std::shared_ptr<impeller::Context> GetImpellerContext() const override;
+
   // |GPUSurfaceMetalDelegate|
   GPUCAMetalLayerHandle GetCAMetalLayer(
       const SkISize& frame_info) const override;

shell/common/shell_test_platform_view_metal.mm

@@ -9,7 +9,9 @@
 #include <utility>
 
 #include "flutter/fml/platform/darwin/scoped_nsobject.h"
+#include "flutter/shell/gpu/gpu_surface_metal_impeller.h"
 #include "flutter/shell/gpu/gpu_surface_metal_skia.h"
+#include "flutter/shell/platform/darwin/graphics/FlutterDarwinContextMetalImpeller.h"
 #include "flutter/shell/platform/darwin/graphics/FlutterDarwinContextMetalSkia.h"
 
 namespace flutter {
@@ -29,12 +31,18 @@
 // non-Objective-C TUs.
 class DarwinContextMetal {
  public:
-  DarwinContextMetal()
-      : context_([[FlutterDarwinContextMetalSkia alloc] initWithDefaultMTLDevice]),
-        offscreen_texture_(CreateOffscreenTexture([context_.get() device])) {}
+  explicit DarwinContextMetal(bool impeller)
+      : context_(impeller ? nil : [[FlutterDarwinContextMetalSkia alloc] initWithDefaultMTLDevice]),
+        impeller_context_(impeller ? [[FlutterDarwinContextMetalImpeller alloc] init] : nil),
+        offscreen_texture_(CreateOffscreenTexture(
+            impeller ? [impeller_context_ context]->GetMTLDevice() : [context_ device])) {}
 
   ~DarwinContextMetal() = default;
 
+  fml::scoped_nsobject<FlutterDarwinContextMetalImpeller> impeller_context() const {
+    return impeller_context_;
+  }
+
   fml::scoped_nsobject<FlutterDarwinContextMetalSkia> context() const { return context_; }
 
   fml::scoped_nsprotocol<id<MTLTexture>> offscreen_texture() const { return offscreen_texture_; }
@@ -48,6 +56,7 @@ GPUMTLTextureInfo offscreen_texture_info() const {
 
  private:
   const fml::scoped_nsobject<FlutterDarwinContextMetalSkia> context_;
+  const fml::scoped_nsobject<FlutterDarwinContextMetalImpeller> impeller_context_;
   const fml::scoped_nsprotocol<id<MTLTexture>> offscreen_texture_;
 
   FML_DISALLOW_COPY_AND_ASSIGN(DarwinContextMetal);
@@ -61,11 +70,15 @@ GPUMTLTextureInfo offscreen_texture_info() const {
     std::shared_ptr<ShellTestExternalViewEmbedder> shell_test_external_view_embedder)
     : ShellTestPlatformView(delegate, task_runners),
       GPUSurfaceMetalDelegate(MTLRenderTargetType::kMTLTexture),
-      metal_context_(std::make_unique<DarwinContextMetal>()),
+      metal_context_(std::make_unique<DarwinContextMetal>(GetSettings().enable_impeller)),
       create_vsync_waiter_(std::move(create_vsync_waiter)),
       vsync_clock_(std::move(vsync_clock)),
       shell_test_external_view_embedder_(std::move(shell_test_external_view_embedder)) {
-  FML_CHECK([metal_context_->context() mainContext] != nil);
+  if (GetSettings().enable_impeller) {
+    FML_CHECK([metal_context_->impeller_context() context] != nil);
+  } else {
+    FML_CHECK([metal_context_->context() mainContext] != nil);
+  }
 }
 
 ShellTestPlatformViewMetal::~ShellTestPlatformViewMetal() = default;
@@ -93,10 +106,19 @@ GPUMTLTextureInfo offscreen_texture_info() const {
 
 // |PlatformView|
 std::unique_ptr<Surface> ShellTestPlatformViewMetal::CreateRenderingSurface() {
+  if (GetSettings().enable_impeller) {
+    return std::make_unique<GPUSurfaceMetalImpeller>(this,
+                                                     [metal_context_->impeller_context() context]);
+  }
   return std::make_unique<GPUSurfaceMetalSkia>(this, [metal_context_->context() mainContext],
                                                MsaaSampleCount::kNone);
 }
 
+// |PlatformView|
+std::shared_ptr<impeller::Context> ShellTestPlatformViewMetal::GetImpellerContext() const {
+  return [metal_context_->impeller_context() context];
+}
+
 // |GPUSurfaceMetalDelegate|
 GPUCAMetalLayerHandle ShellTestPlatformViewMetal::GetCAMetalLayer(const SkISize& frame_info) const {
   FML_CHECK(false) << "A Metal Delegate configured with MTLRenderTargetType::kMTLTexture was asked "

shell/common/shell_unittests.cc

@@ -3986,6 +3986,53 @@ TEST_F(ShellTest, PictureToImageSync) {
   DestroyShell(std::move(shell));
 }
 
+TEST_F(ShellTest, PictureToImageSyncImpellerNoSurface) {
+#if !SHELL_ENABLE_METAL
+  // This test uses the Metal backend.
+  GTEST_SKIP();
+#endif  // !SHELL_ENABLE_METAL
+  auto settings = CreateSettingsForFixture();
+  settings.enable_impeller = true;
+  std::unique_ptr<Shell> shell =
+      CreateShell(settings,                                          //
+                  GetTaskRunnersForFixture(),                        //
+                  false,                                             //
+                  nullptr,                                           //
+                  false,                                             //
+                  ShellTestPlatformView::BackendType::kMetalBackend  //
+      );
+
+  AddNativeCallback("NativeOnBeforeToImageSync",
+                    CREATE_NATIVE_ENTRY([&](auto args) {
+                      // nop
+                    }));
+
+  fml::CountDownLatch latch(2);
+  AddNativeCallback("NotifyNative", CREATE_NATIVE_ENTRY([&](auto args) {
+                      // Teardown and set up rasterizer again.
+                      PlatformViewNotifyDestroyed(shell.get());
+                      PlatformViewNotifyCreated(shell.get());
+                      latch.CountDown();
+                    }));
+
+  ASSERT_NE(shell, nullptr);
+  ASSERT_TRUE(shell->IsSetup());
+  auto configuration = RunConfiguration::InferFromSettings(settings);
+
+  // Important: Do not create the platform view yet!
+  // This test is making sure that the rasterizer can create the texture
+  // as expected without a surface.
+
+  configuration.SetEntrypoint("toImageSync");
+  RunEngine(shell.get(), std::move(configuration));
+  PumpOneFrame(shell.get());
+
+  latch.Wait();
+
+  PlatformViewNotifyDestroyed(shell.get());
+  DestroyShell(std::move(shell));
+}
+
 #if SHELL_ENABLE_GL
 // This test uses the GL backend and refers to symbols in egl.h
 TEST_F(ShellTest, PictureToImageSyncWithTrampledContext) {

shell/common/snapshot_controller.h

@@ -12,6 +12,10 @@
 #include "flutter/lib/ui/snapshot_delegate.h"
 #include "flutter/shell/common/snapshot_surface_producer.h"
 
+namespace impeller {
+class AiksContext;
+}
+
 namespace flutter {
 
 class SnapshotController {
@@ -20,6 +24,7 @@ class SnapshotController {
    public:
     virtual ~Delegate() = default;
     virtual const std::unique_ptr<Surface>& GetSurface() const = 0;
+    virtual std::shared_ptr<impeller::AiksContext> GetAiksContext() const = 0;
     virtual const std::unique_ptr<SnapshotSurfaceProducer>&
     GetSnapshotSurfaceProducer() const = 0;
     virtual std::shared_ptr<const fml::SyncSwitch> GetIsGpuDisabledSyncSwitch()

shell/common/snapshot_controller_impeller.cc

@@ -36,11 +36,8 @@ sk_sp<DlImage> SnapshotControllerImpeller::DoMakeRasterSnapshot(
   impeller::DisplayListDispatcher dispatcher;
   display_list->Dispatch(dispatcher);
   impeller::Picture picture = dispatcher.EndRecordingAsPicture();
-  if (GetDelegate().GetSurface() &&
-      GetDelegate().GetSurface()->GetAiksContext()) {
-    impeller::AiksContext* context =
-        GetDelegate().GetSurface()->GetAiksContext();
-
+  auto context = GetDelegate().GetAiksContext();
+  if (context) {
     auto max_size = context->GetContext()
                         ->GetResourceAllocator()
                         ->GetMaxTextureSizeSupported();

shell/gpu/gpu_surface_gl_impeller.cc

@@ -160,8 +160,9 @@ bool GPUSurfaceGLImpeller::EnableRasterCache() const {
 }
 
 // |Surface|
-impeller::AiksContext* GPUSurfaceGLImpeller::GetAiksContext() const {
-  return aiks_context_.get();
+std::shared_ptr<impeller::AiksContext> GPUSurfaceGLImpeller::GetAiksContext()
+    const {
+  return aiks_context_;
 }
 
 }  // namespace flutter

shell/gpu/gpu_surface_gl_impeller.h

@@ -56,7 +56,7 @@ class GPUSurfaceGLImpeller final : public Surface {
   bool EnableRasterCache() const override;
 
   // |Surface|
-  impeller::AiksContext* GetAiksContext() const override;
+  std::shared_ptr<impeller::AiksContext> GetAiksContext() const override;
 
   FML_DISALLOW_COPY_AND_ASSIGN(GPUSurfaceGLImpeller);
 };

shell/gpu/gpu_surface_metal_impeller.h

@@ -54,7 +54,7 @@ class SK_API_AVAILABLE_CA_METAL_LAYER GPUSurfaceMetalImpeller : public Surface {
   bool EnableRasterCache() const override;
 
   // |Surface|
-  impeller::AiksContext* GetAiksContext() const override;
+  std::shared_ptr<impeller::AiksContext> GetAiksContext() const override;
 
   FML_DISALLOW_COPY_AND_ASSIGN(GPUSurfaceMetalImpeller);
 };

shell/gpu/gpu_surface_metal_impeller.mm

@@ -129,8 +129,8 @@
 }
 
 // |Surface|
-impeller::AiksContext* GPUSurfaceMetalImpeller::GetAiksContext() const {
-  return aiks_context_.get();
+std::shared_ptr<impeller::AiksContext> GPUSurfaceMetalImpeller::GetAiksContext() const {
+  return aiks_context_;
 }
 
 Surface::SurfaceData GPUSurfaceMetalImpeller::GetSurfaceData() const {

shell/gpu/gpu_surface_vulkan_impeller.cc

@@ -122,8 +122,9 @@ bool GPUSurfaceVulkanImpeller::EnableRasterCache() const {
 }
 
 // |Surface|
-impeller::AiksContext* GPUSurfaceVulkanImpeller::GetAiksContext() const {
-  return aiks_context_.get();
+std::shared_ptr<impeller::AiksContext>
+GPUSurfaceVulkanImpeller::GetAiksContext() const {
+  return aiks_context_;
 }
 
 }  // namespace flutter

shell/gpu/gpu_surface_vulkan_impeller.h

@@ -47,7 +47,7 @@ class GPUSurfaceVulkanImpeller final : public Surface {
   bool EnableRasterCache() const override;
 
   // |Surface|
-  impeller::AiksContext* GetAiksContext() const override;
+  std::shared_ptr<impeller::AiksContext> GetAiksContext() const override;
 
   FML_DISALLOW_COPY_AND_ASSIGN(GPUSurfaceVulkanImpeller);
 };