Platform View implemenation for Metal

ci/licenses_golden/licenses_flutter

@@ -511,6 +511,7 @@ FILE: ../../../flutter/shell/common/vsync_waiter_fallback.cc
 FILE: ../../../flutter/shell/common/vsync_waiter_fallback.h
 FILE: ../../../flutter/shell/gpu/gpu_surface_gl.cc
 FILE: ../../../flutter/shell/gpu/gpu_surface_gl.h
+FILE: ../../../flutter/shell/gpu/gpu_surface_delegate.h
 FILE: ../../../flutter/shell/gpu/gpu_surface_gl_delegate.cc
 FILE: ../../../flutter/shell/gpu/gpu_surface_gl_delegate.h
 FILE: ../../../flutter/shell/gpu/gpu_surface_metal.h

shell/common/animator.cc

@@ -27,22 +27,27 @@ Animator::Animator(Delegate& delegate,
       waiter_(std::move(waiter)),
       last_begin_frame_time_(),
       dart_frame_deadline_(0),
+#if FLUTTER_SHELL_ENABLE_METAL
+      layer_tree_pipeline_(fml::MakeRefCounted<LayerTreePipeline>(2)),
+#else   // FLUTTER_SHELL_ENABLE_METAL
       // TODO(dnfield): We should remove this logic and set the pipeline depth
-      // back to 2 in this case. See https://github.com/flutter/engine/pull/9132
-      // for discussion.
+      // back to 2 in this case. See
+      // https://github.com/flutter/engine/pull/9132 for discussion.
       layer_tree_pipeline_(fml::MakeRefCounted<LayerTreePipeline>(
           task_runners.GetPlatformTaskRunner() ==
                   task_runners.GetGPUTaskRunner()
               ? 1
               : 2)),
+#endif  // FLUTTER_SHELL_ENABLE_METAL
       pending_frame_semaphore_(1),
       frame_number_(1),
       paused_(false),
       regenerate_layer_tree_(false),
       frame_scheduled_(false),
       notify_idle_task_id_(0),
       dimension_change_pending_(false),
-      weak_factory_(this) {}
+      weak_factory_(this) {
+}
 
 Animator::~Animator() = default;
 

shell/gpu/BUILD.gn

@@ -27,6 +27,7 @@ source_set("gpu_surface_software") {
 
 source_set("gpu_surface_gl") {
   sources = [
+    "$gpu_dir/gpu_surface_delegate.h",
     "$gpu_dir/gpu_surface_gl.cc",
     "$gpu_dir/gpu_surface_gl.h",
     "$gpu_dir/gpu_surface_gl_delegate.cc",
@@ -50,6 +51,7 @@ source_set("gpu_surface_vulkan") {
 
 source_set("gpu_surface_metal") {
   sources = [
+    "$gpu_dir/gpu_surface_delegate.h",
     "$gpu_dir/gpu_surface_metal.h",
     "$gpu_dir/gpu_surface_metal.mm",
   ]

shell/gpu/gpu_surface_delegate.h

@@ -0,0 +1,18 @@
+#ifndef FLUTTER_SHELL_GPU_GPU_SURFACE_DELEGATE_H_
+#define FLUTTER_SHELL_GPU_GPU_SURFACE_DELEGATE_H_
+
+#include "flutter/flow/embedded_views.h"
+#include "flutter/fml/macros.h"
+
+namespace flutter {
+
+class GPUSurfaceDelegate {
+ public:
+  // Get a reference to the external views embedder. This happens on the same
+  // thread that the renderer is operating on.
+  virtual ExternalViewEmbedder* GetExternalViewEmbedder() = 0;
+};
+
+}  // namespace flutter
+
+#endif  // FLUTTER_SHELL_GPU_GPU_SURFACE_DELEGATE_H_

shell/gpu/gpu_surface_gl_delegate.h

@@ -7,12 +7,13 @@
 
 #include "flutter/flow/embedded_views.h"
 #include "flutter/fml/macros.h"
+#include "flutter/shell/gpu/gpu_surface_delegate.h"
 #include "third_party/skia/include/core/SkMatrix.h"
 #include "third_party/skia/include/gpu/gl/GrGLInterface.h"
 
 namespace flutter {
 
-class GPUSurfaceGLDelegate {
+class GPUSurfaceGLDelegate : public GPUSurfaceDelegate {
  public:
   // Called to make the main GL context current on the current thread.
   virtual bool GLContextMakeCurrent() = 0;
@@ -42,10 +43,6 @@ class GPUSurfaceGLDelegate {
   // flushed.
   virtual SkMatrix GLContextSurfaceTransformation() const;
 
-  // Get a reference to the external views embedder. This happens on the same
-  // thread that the renderer is operating on.
-  virtual ExternalViewEmbedder* GetExternalViewEmbedder() = 0;
-
   sk_sp<const GrGLInterface> GetGLInterface() const;
 
   // TODO(chinmaygarde): The presence of this method is to work around the fact

shell/gpu/gpu_surface_metal.h

@@ -10,6 +10,7 @@
 #include "flutter/fml/macros.h"
 #include "flutter/fml/platform/darwin/scoped_nsobject.h"
 #include "flutter/shell/common/surface.h"
+#include "flutter/shell/gpu/gpu_surface_delegate.h"
 #include "third_party/skia/include/gpu/GrContext.h"
 
 @class CAMetalLayer;
@@ -18,11 +19,15 @@ namespace flutter {
 
 class GPUSurfaceMetal : public Surface {
  public:
-  GPUSurfaceMetal(fml::scoped_nsobject<CAMetalLayer> layer);
+  GPUSurfaceMetal(GPUSurfaceDelegate* delegate, fml::scoped_nsobject<CAMetalLayer> layer);
+  GPUSurfaceMetal(GPUSurfaceDelegate* delegate,
+                  sk_sp<GrContext> gr_context,
+                  fml::scoped_nsobject<CAMetalLayer> layer);
 
   ~GPUSurfaceMetal() override;
 
  private:
+  GPUSurfaceDelegate* delegate_;
   fml::scoped_nsobject<CAMetalLayer> layer_;
   sk_sp<GrContext> context_;
   fml::scoped_nsprotocol<id<MTLCommandQueue>> command_queue_;
@@ -39,6 +44,9 @@ class GPUSurfaceMetal : public Surface {
   // |Surface|
   GrContext* GetContext() override;
 
+  // |Surface|
+  flutter::ExternalViewEmbedder* GetExternalViewEmbedder() override;
+
   // |Surface|
   bool MakeRenderContextCurrent() override;
 

shell/gpu/gpu_surface_metal.mm

@@ -12,8 +12,9 @@
 
 namespace flutter {
 
-GPUSurfaceMetal::GPUSurfaceMetal(fml::scoped_nsobject<CAMetalLayer> layer)
-    : layer_(std::move(layer)) {
+GPUSurfaceMetal::GPUSurfaceMetal(GPUSurfaceDelegate* delegate,
+                                 fml::scoped_nsobject<CAMetalLayer> layer)
+    : delegate_(delegate), layer_(std::move(layer)) {
   if (!layer_) {
     FML_LOG(ERROR) << "Could not create metal surface because of invalid layer.";
     return;
@@ -41,6 +42,32 @@
   context_ = context;
 }
 
+GPUSurfaceMetal::GPUSurfaceMetal(GPUSurfaceDelegate* delegate,
+                                 sk_sp<GrContext> gr_context,
+                                 fml::scoped_nsobject<CAMetalLayer> layer)
+    : delegate_(delegate), layer_(std::move(layer)), context_(gr_context) {
+  if (!layer_) {
+    FML_LOG(ERROR) << "Could not create metal surface because of invalid layer.";
+    return;
+  }
+  if (!context_) {
+    FML_LOG(ERROR) << "Could not create metal surface because of invalid Skia metal context.";
+    return;
+  }
+
+  layer.get().pixelFormat = MTLPixelFormatBGRA8Unorm;
+
+  auto metal_device = fml::scoped_nsprotocol<id<MTLDevice>>([layer_.get().device retain]);
+  auto metal_queue = fml::scoped_nsprotocol<id<MTLCommandQueue>>([metal_device newCommandQueue]);
+
+  if (!metal_device || !metal_queue) {
+    FML_LOG(ERROR) << "Could not create metal device or queue.";
+    return;
+  }
+
+  command_queue_ = metal_queue;
+}
+
 GPUSurfaceMetal::~GPUSurfaceMetal() = default;
 
 // |Surface|
@@ -112,11 +139,25 @@ GrBackendRenderTarget metal_render_target(bounds.width * scale,   // width
     return nullptr;
   }
 
-  auto submit_callback = [drawable = next_drawable, command_buffer](
+  // External views need to present with transaction. When presenting with
+  // transaction, we have to block, otherwise we risk presenting the drawable
+  // after the CATransaction has completed.
+  // See:
+  // https://developer.apple.com/documentation/quartzcore/cametallayer/1478157-presentswithtransaction
+  // TODO(dnfield): only do this if transactions are actually being used.
+  // https://github.com/flutter/flutter/issues/24133
+  bool wait = delegate_->GetExternalViewEmbedder() != nullptr;
+
+  auto submit_callback = [drawable = next_drawable, command_buffer, wait](
                              const SurfaceFrame& surface_frame, SkCanvas* canvas) -> bool {
     canvas->flush();
-    [command_buffer.get() presentDrawable:drawable.get()];
     [command_buffer.get() commit];
+    if (!wait) {
+      [command_buffer.get() presentDrawable:drawable.get()];
+    } else {
+      [command_buffer.get() waitUntilScheduled];
+      [drawable.get() present];
+    }
     return true;
   };
 
@@ -137,6 +178,11 @@ GrBackendRenderTarget metal_render_target(bounds.width * scale,   // width
   return context_.get();
 }
 
+// |Surface|
+flutter::ExternalViewEmbedder* GPUSurfaceMetal::GetExternalViewEmbedder() {
+  return delegate_->GetExternalViewEmbedder();
+}
+
 // |Surface|
 bool GPUSurfaceMetal::MakeRenderContextCurrent() {
   // This backend has no such concept.

shell/platform/darwin/ios/framework/Source/FlutterOverlayView.h

@@ -24,8 +24,7 @@
 
 - (instancetype)init NS_DESIGNATED_INITIALIZER;
 - (instancetype)initWithContentsScale:(CGFloat)contentsScale;
-- (std::unique_ptr<flutter::IOSSurface>)createSoftwareSurface;
-- (std::unique_ptr<flutter::IOSSurfaceGL>)createGLSurfaceWithContext:
+- (std::unique_ptr<flutter::IOSSurface>)createSurface:
     (std::shared_ptr<flutter::IOSGLContext>)gl_context;
 
 @end

shell/platform/darwin/ios/framework/Source/FlutterOverlayView.mm

@@ -13,6 +13,7 @@
 #include "flutter/shell/common/platform_view.h"
 #include "flutter/shell/common/rasterizer.h"
 #include "flutter/shell/platform/darwin/ios/ios_surface_gl.h"
+#include "flutter/shell/platform/darwin/ios/ios_surface_metal.h"
 #include "flutter/shell/platform/darwin/ios/ios_surface_software.h"
 #include "third_party/skia/include/utils/mac/SkCGUtils.h"
 
@@ -51,6 +52,13 @@ - (instancetype)initWithContentsScale:(CGFloat)contentsScale {
     layer.allowsGroupOpacity = NO;
     layer.contentsScale = contentsScale;
     layer.rasterizationScale = contentsScale;
+#if FLUTTER_SHELL_ENABLE_METAL
+  } else if ([self.layer isKindOfClass:[CAMetalLayer class]]) {
+    CAMetalLayer* layer = reinterpret_cast<CAMetalLayer*>(self.layer);
+    layer.allowsGroupOpacity = NO;
+    layer.contentsScale = contentsScale;
+    layer.rasterizationScale = contentsScale;
+#endif  // FLUTTER_SHELL_ENABLE_METAL
   }
 
   return self;
@@ -59,27 +67,39 @@ - (instancetype)initWithContentsScale:(CGFloat)contentsScale {
 + (Class)layerClass {
 #if TARGET_IPHONE_SIMULATOR
   return [CALayer class];
-#else   // TARGET_IPHONE_SIMULATOR
+#else  // TARGET_IPHONE_SIMULATOR
+#if FLUTTER_SHELL_ENABLE_METAL
+  return [CAMetalLayer class];
+#else   // FLUTTER_SHELL_ENABLE_METAL
   return [CAEAGLLayer class];
+#endif  //  FLUTTER_SHELL_ENABLE_METAL
 #endif  // TARGET_IPHONE_SIMULATOR
 }
 
-- (std::unique_ptr<flutter::IOSSurface>)createSoftwareSurface {
-  fml::scoped_nsobject<CALayer> layer(reinterpret_cast<CALayer*>([self.layer retain]));
-  return std::make_unique<flutter::IOSSurfaceSoftware>(std::move(layer), nullptr);
-}
-
-- (std::unique_ptr<flutter::IOSSurfaceGL>)createGLSurfaceWithContext:
+- (std::unique_ptr<flutter::IOSSurface>)createSurface:
     (std::shared_ptr<flutter::IOSGLContext>)gl_context {
-  fml::scoped_nsobject<CAEAGLLayer> eagl_layer(reinterpret_cast<CAEAGLLayer*>([self.layer retain]));
-  // TODO(amirh): We can lower this to iOS 8.0 once we have a Metal rendering backend.
-  // https://github.com/flutter/flutter/issues/24132
-  if (@available(iOS 9.0, *)) {
-    eagl_layer.get().presentsWithTransaction = YES;
+  if ([self.layer isKindOfClass:[CAEAGLLayer class]]) {
+    fml::scoped_nsobject<CAEAGLLayer> eagl_layer(
+        reinterpret_cast<CAEAGLLayer*>([self.layer retain]));
+    if (@available(iOS 9.0, *)) {
+      eagl_layer.get().presentsWithTransaction = YES;
+    }
+    return std::make_unique<flutter::IOSSurfaceGL>(std::move(eagl_layer), gl_context);
+#if FLUTTER_SHELL_ENABLE_METAL
+  } else if ([self.layer isKindOfClass:[CAMetalLayer class]]) {
+    fml::scoped_nsobject<CAMetalLayer> metalLayer(
+        reinterpret_cast<CAMetalLayer*>([self.layer retain]));
+    if (@available(iOS 8.0, *)) {
+      metalLayer.get().presentsWithTransaction = YES;
+    }
+    return std::make_unique<flutter::IOSSurfaceMetal>(std::move(metalLayer));
+#endif  //  FLUTTER_SHELL_ENABLE_METAL
+  } else {
+    fml::scoped_nsobject<CALayer> layer(reinterpret_cast<CALayer*>([self.layer retain]));
+    return std::make_unique<flutter::IOSSurfaceSoftware>(std::move(layer), nullptr);
   }
-  return std::make_unique<flutter::IOSSurfaceGL>(eagl_layer, std::move(gl_context));
 }
 
-// TODO(amirh): implement drawLayer to suppoer snapshotting.
+// TODO(amirh): implement drawLayer to support snapshotting.
 
 @end