Add support for rendering using Metal on macOS (flutter#23599)

Author: iskakaushik

ci/licenses_golden/licenses_flutter

@@ -1062,6 +1062,8 @@ FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FlutterPlug
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FlutterViewController.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Info.plist
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterAppDelegate.mm
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterBackingStore.h
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterBackingStore.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterBackingStoreData.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterBackingStoreData.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterDartProject.mm
@@ -1080,11 +1082,18 @@ FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterIOSur
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterIOSurfaceHolder.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterIntermediateKeyResponder.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterIntermediateKeyResponder.mm
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterMetalRenderer.h
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterMetalRenderer.mm
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterMetalRendererTest.mm
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterMetalSurfaceManagerTest.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterMouseCursorPlugin.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterOpenGLRenderer.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterOpenGLRenderer.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterOpenGLRendererTest.mm
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterRenderer.h
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterResizableBackingStoreProvider.h
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterResizableBackingStoreProvider.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterResizeSynchronizer.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterResizeSynchronizer.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterSurfaceManager.h

shell/platform/darwin/graphics/FlutterDarwinContextMetal.h

@@ -26,19 +26,19 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * Initializes a FlutterDarwinContextMetal with provided MTLDevice and MTLCommandQueue.
  */
-- (instancetype)initWithMTLDevice:(id<MTLDevice>)mtlDevice
+- (instancetype)initWithMTLDevice:(id<MTLDevice>)device
                      commandQueue:(id<MTLCommandQueue>)commandQueue;
 
 /**
  * MTLDevice that is backing this context.s
  */
-@property(nonatomic, readonly) id<MTLDevice> mtlDevice;
+@property(nonatomic, readonly) id<MTLDevice> device;
 
 /**
- * MTLCommandQueue that is acquired from the `mtlDevice`. This queue is used both for rendering and
+ * MTLCommandQueue that is acquired from the `device`. This queue is used both for rendering and
  * resource related commands.
  */
-@property(nonatomic, readonly) id<MTLCommandQueue> mtlCommandQueue;
+@property(nonatomic, readonly) id<MTLCommandQueue> commandQueue;
 
 /**
  * Skia GrContext that is used for rendering.

shell/platform/darwin/graphics/FlutterDarwinContextMetal.mm

@@ -21,40 +21,40 @@ static GrContextOptions CreateMetalGrContextOptions() {
 @implementation FlutterDarwinContextMetal
 
 - (instancetype)initWithDefaultMTLDevice {
-  id<MTLDevice> mtlDevice = MTLCreateSystemDefaultDevice();
-  return [self initWithMTLDevice:mtlDevice commandQueue:[mtlDevice newCommandQueue]];
+  id<MTLDevice> device = MTLCreateSystemDefaultDevice();
+  return [self initWithMTLDevice:device commandQueue:[device newCommandQueue]];
 }
 
-- (instancetype)initWithMTLDevice:(id<MTLDevice>)mtlDevice
+- (instancetype)initWithMTLDevice:(id<MTLDevice>)device
                      commandQueue:(id<MTLCommandQueue>)commandQueue {
   self = [super init];
   if (self != nil) {
-    _mtlDevice = mtlDevice;
+    _device = device;
 
-    if (!_mtlDevice) {
+    if (!_device) {
       FML_DLOG(ERROR) << "Could not acquire Metal device.";
       [self release];
       return nil;
     }
 
-    _mtlCommandQueue = commandQueue;
+    _commandQueue = commandQueue;
 
-    if (!_mtlCommandQueue) {
+    if (!_commandQueue) {
       FML_DLOG(ERROR) << "Could not create Metal command queue.";
       [self release];
       return nil;
     }
 
-    [_mtlCommandQueue setLabel:@"Flutter Main Queue"];
+    [_commandQueue setLabel:@"Flutter Main Queue"];
 
     auto contextOptions = CreateMetalGrContextOptions();
 
     // Skia expect arguments to `MakeMetal` transfer ownership of the reference in for release later
     // when the GrDirectContext is collected.
     _mainContext =
-        GrDirectContext::MakeMetal([_mtlDevice retain], [_mtlCommandQueue retain], contextOptions);
+        GrDirectContext::MakeMetal([_device retain], [_commandQueue retain], contextOptions);
     _resourceContext =
-        GrDirectContext::MakeMetal([_mtlDevice retain], [_mtlCommandQueue retain], contextOptions);
+        GrDirectContext::MakeMetal([_device retain], [_commandQueue retain], contextOptions);
 
     if (!_mainContext || !_resourceContext) {
       FML_DLOG(ERROR) << "Could not create Skia Metal contexts.";

shell/platform/darwin/ios/ios_context_metal.mm

@@ -20,12 +20,12 @@
     return;
   }
 
-  main_command_queue_.reset([darwin_context_metal_.get().mtlCommandQueue retain]);
+  main_command_queue_.reset([darwin_context_metal_.get().commandQueue retain]);
 
   CVMetalTextureCacheRef texture_cache_raw = NULL;
   auto cv_return = CVMetalTextureCacheCreate(kCFAllocatorDefault,  // allocator
                                              NULL,  // cache attributes (NULL default)
-                                             darwin_context_metal_.get().mtlDevice,  // metal device
+                                             darwin_context_metal_.get().device,  // metal device
                                              NULL,  // texture attributes (NULL default)
                                              &texture_cache_raw  // [out] cache
   );

shell/platform/darwin/ios/ios_surface_metal.mm

@@ -22,8 +22,8 @@
   is_valid_ = layer_;
   auto metal_context = CastToMetalContext(GetContext());
   auto darwin_context = metal_context->GetDarwinContext().get();
-  command_queue_ = darwin_context.mtlCommandQueue;
-  device_ = darwin_context.mtlDevice;
+  command_queue_ = darwin_context.commandQueue;
+  device_ = darwin_context.device;
 }
 
 // |IOSSurface|

shell/platform/darwin/macos/BUILD.gn

@@ -5,11 +5,18 @@
 assert(is_mac)
 
 import("//build/config/mac/mac_sdk.gni")
-import("//flutter/common/config.gni")
+import("//flutter/shell/gpu/gpu.gni")
 import("//flutter/shell/platform/darwin/common/framework_shared.gni")
 import("//flutter/shell/platform/glfw/config.gni")
 import("//flutter/testing/testing.gni")
 
+shell_gpu_configuration("macos_gpu_configuration") {
+  enable_software = true
+  enable_gl = true
+  enable_vulkan = false
+  enable_metal = shell_enable_metal
+}
+
 group("macos") {
   deps = [ ":flutter_framework" ]
   if (build_glfw_shell) {
@@ -46,6 +53,8 @@ source_set("flutter_framework_source") {
 
   sources = [
     "framework/Source/FlutterAppDelegate.mm",
+    "framework/Source/FlutterBackingStore.h",
+    "framework/Source/FlutterBackingStore.mm",
     "framework/Source/FlutterBackingStoreData.h",
     "framework/Source/FlutterBackingStoreData.mm",
     "framework/Source/FlutterDartProject.mm",
@@ -62,10 +71,15 @@ source_set("flutter_framework_source") {
     "framework/Source/FlutterIOSurfaceHolder.mm",
     "framework/Source/FlutterIntermediateKeyResponder.h",
     "framework/Source/FlutterIntermediateKeyResponder.mm",
+    "framework/Source/FlutterMetalRenderer.h",
+    "framework/Source/FlutterMetalRenderer.mm",
     "framework/Source/FlutterMouseCursorPlugin.h",
     "framework/Source/FlutterMouseCursorPlugin.mm",
     "framework/Source/FlutterOpenGLRenderer.h",
     "framework/Source/FlutterOpenGLRenderer.mm",
+    "framework/Source/FlutterRenderer.h",
+    "framework/Source/FlutterResizableBackingStoreProvider.h",
+    "framework/Source/FlutterResizableBackingStoreProvider.mm",
     "framework/Source/FlutterResizeSynchronizer.h",
     "framework/Source/FlutterResizeSynchronizer.mm",
     "framework/Source/FlutterSurfaceManager.h",
@@ -85,6 +99,7 @@ source_set("flutter_framework_source") {
   sources += _flutter_framework_headers
 
   deps = [
+    ":macos_gpu_configuration",
     "//flutter/flow:flow",
     "//flutter/fml",
     "//flutter/shell/platform/common/cpp:common_cpp_switches",
@@ -106,6 +121,7 @@ source_set("flutter_framework_source") {
     "Cocoa.framework",
     "CoreVideo.framework",
     "IOSurface.framework",
+    "Metal.framework",
     "QuartzCore.framework",
   ]
 }
@@ -131,12 +147,20 @@ executable("flutter_desktop_darwin_unittests") {
   sources = [
     "framework/Source/FlutterEngineTest.mm",
     "framework/Source/FlutterGLCompositorUnittests.mm",
-    "framework/Source/FlutterOpenGLRendererTest.mm",
     "framework/Source/FlutterViewControllerTest.mm",
     "framework/Source/FlutterViewControllerTestUtils.h",
     "framework/Source/FlutterViewControllerTestUtils.mm",
   ]
 
+  if (shell_enable_metal) {
+    sources += [
+      "framework/Source/FlutterMetalRendererTest.mm",
+      "framework/Source/FlutterMetalSurfaceManagerTest.mm",
+    ]
+  } else {
+    sources += [ "framework/Source/FlutterOpenGLRendererTest.mm" ]
+  }
+
   cflags_objcc = [ "-fobjc-arc" ]
 
   ldflags = [ "-ObjC" ]

shell/platform/darwin/macos/framework/Source/FlutterBackingStore.h

@@ -0,0 +1,48 @@
+// 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.
+
+#import <Cocoa/Cocoa.h>
+#import <Metal/Metal.h>
+
+/**
+ * Interface for backing store handles. Typically contain references to the buffers that
+ * are handed by the `FlutterView` to the `FlutterRenderer`.
+ */
+@interface FlutterRenderBackingStore : NSObject
+
+@end
+
+/**
+ * Wraps an OpenGL frame buffer.
+ */
+@interface FlutterOpenGLRenderBackingStore : FlutterRenderBackingStore
+
+/**
+ * Frame buffer ID referenced by this backing store instance.
+ */
+@property(nonatomic, readonly) uint32_t frameBufferID;
+
+/**
+ * Initializes a backing store with the specified frame buffer id.
+ */
+- (nonnull instancetype)initWithFrameBufferID:(uint32_t)fboID;
+
+@end
+
+/**
+ * Wraps a Metal texture.
+ */
+@interface FlutterMetalRenderBackingStore : FlutterRenderBackingStore
+
+/**
+ * MTLTexture referenced by this backing store instance.
+ */
+@property(nonnull, nonatomic, readonly) id<MTLTexture> texture;
+
+/**
+ * Initializes a backing store with the specified MTLTexture.
+ */
+- (nonnull instancetype)initWithTexture:(nonnull id<MTLTexture>)texture;
+
+@end

shell/platform/darwin/macos/framework/Source/FlutterBackingStore.mm

@@ -0,0 +1,32 @@
+// 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.
+
+#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterBackingStore.h"
+
+@implementation FlutterRenderBackingStore
+@end
+
+@implementation FlutterOpenGLRenderBackingStore
+
+- (instancetype)initWithFrameBufferID:(uint32_t)fboID {
+  self = [super init];
+  if (self) {
+    _frameBufferID = fboID;
+  }
+  return self;
+}
+
+@end
+
+@implementation FlutterMetalRenderBackingStore
+
+- (instancetype)initWithTexture:(id<MTLTexture>)texture {
+  self = [super init];
+  if (self) {
+    _texture = texture;
+  }
+  return self;
+}
+
+@end

shell/platform/darwin/macos/framework/Source/FlutterBackingStoreData.mm

@@ -3,11 +3,12 @@
 // found in the LICENSE file.
 
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterBackingStoreData.h"
+
+#import <OpenGL/gl.h>
+
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterFrameBufferProvider.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterIOSurfaceHolder.h"
 
-#include <OpenGL/gl.h>
-
 @implementation FlutterBackingStoreData
 
 - (nullable instancetype)initWithLayerId:(size_t)layerId