[metal] Darwin unified external metal textures

common/graphics/texture.h

@@ -18,8 +18,8 @@ namespace flutter {
 
 class Texture {
  public:
-  Texture(int64_t id);  // Called from UI or raster thread.
-  virtual ~Texture();   // Called from raster thread.
+  explicit Texture(int64_t id);  // Called from UI or raster thread.
+  virtual ~Texture();            // Called from raster thread.
 
   // Called from raster thread.
   virtual void Paint(SkCanvas& canvas,

shell/platform/darwin/graphics/BUILD.gn

@@ -7,19 +7,23 @@ assert(is_ios || is_mac)
 import("//flutter/common/config.gni")
 
 source_set("graphics") {
-  cflags_objc = flutter_cflags_objc
-  cflags_objcc = flutter_cflags_objcc
+  cflags_objcc = [ "-fobjc-arc" ]
 
   sources = [
     "FlutterDarwinContextMetal.h",
     "FlutterDarwinContextMetal.mm",
+    "FlutterDarwinExternalTextureMetal.h",
+    "FlutterDarwinExternalTextureMetal.mm",
   ]
 
   deps = [
     "//flutter/common/graphics",
     "//flutter/fml",
+    "//flutter/shell/platform/darwin/common:framework_shared",
   ]
 
+  libs = [ "CoreVideo.framework" ]
+
   public_deps = [ "//third_party/skia" ]
 
   public_configs = [ "//flutter:config" ]

shell/platform/darwin/graphics/FlutterDarwinContextMetal.h

@@ -5,9 +5,12 @@
 #ifndef SHELL_PLATFORM_DARWIN_GRAPHICS_DARWIN_CONTEXT_METAL_H_
 #define SHELL_PLATFORM_DARWIN_GRAPHICS_DARWIN_CONTEXT_METAL_H_
 
+#import <CoreVideo/CVMetalTextureCache.h>
 #import <Foundation/Foundation.h>
 #import <Metal/Metal.h>
 
+#import "flutter/shell/platform/darwin/common/framework/Headers/FlutterTexture.h"
+#import "flutter/shell/platform/darwin/graphics/FlutterDarwinExternalTextureMetal.h"
 #include "third_party/skia/include/gpu/GrDirectContext.h"
 
 NS_ASSUME_NONNULL_BEGIN
@@ -29,6 +32,12 @@ NS_ASSUME_NONNULL_BEGIN
 - (instancetype)initWithMTLDevice:(id<MTLDevice>)device
                      commandQueue:(id<MTLCommandQueue>)commandQueue;
 
+/**
+ * Creates an external texture with the specified ID and contents.
+ */
+- (FlutterDarwinExternalTextureMetal*)externalTextureWithID:(int64_t)textureID
+                                                    texture:(NSObject<FlutterTexture>*)texture;
+
 /**
  * MTLDevice that is backing this context.s
  */
@@ -50,6 +59,11 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property(nonatomic, readonly) sk_sp<GrDirectContext> resourceContext;
 
+/*
+ * Texture cache for external textures.
+ */
+@property(nonatomic, readonly) CVMetalTextureCacheRef textureCache;
+
 @end
 
 NS_ASSUME_NONNULL_END

shell/platform/darwin/graphics/FlutterDarwinContextMetal.mm

@@ -33,32 +33,39 @@ - (instancetype)initWithMTLDevice:(id<MTLDevice>)device
 
     if (!_device) {
       FML_DLOG(ERROR) << "Could not acquire Metal device.";
-      [self release];
       return nil;
     }
 
     _commandQueue = commandQueue;
 
     if (!_commandQueue) {
       FML_DLOG(ERROR) << "Could not create Metal command queue.";
-      [self release];
       return nil;
     }
 
     [_commandQueue setLabel:@"Flutter Main Queue"];
 
+    CVReturn cvReturn = CVMetalTextureCacheCreate(kCFAllocatorDefault,  // allocator
+                                                  nil,      // cache attributes (nil default)
+                                                  _device,  // metal device
+                                                  nil,      // texture attributes (nil default)
+                                                  &_textureCache  // [out] cache
+    );
+    if (cvReturn != kCVReturnSuccess) {
+      FML_DLOG(ERROR) << "Could not create Metal texture cache.";
+      return nil;
+    }
+
     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([_device retain], [_commandQueue retain], contextOptions);
-    _resourceContext =
-        GrDirectContext::MakeMetal([_device retain], [_commandQueue retain], contextOptions);
+    _mainContext = GrDirectContext::MakeMetal(
+        (__bridge_retained void*)_device, (__bridge_retained void*)_commandQueue, contextOptions);
+    _resourceContext = _mainContext;
 
     if (!_mainContext || !_resourceContext) {
       FML_DLOG(ERROR) << "Could not create Skia Metal contexts.";
-      [self release];
       return nil;
     }
 
@@ -67,4 +74,11 @@ - (instancetype)initWithMTLDevice:(id<MTLDevice>)device
   return self;
 }
 
+- (FlutterDarwinExternalTextureMetal*)externalTextureWithID:(int64_t)textureID
+                                                    texture:(NSObject<FlutterTexture>*)texture {
+  return [[FlutterDarwinExternalTextureMetal alloc] initWithTextureCache:_textureCache
+                                                               textureID:textureID
+                                                                 texture:texture];
+}
+
 @end

shell/platform/darwin/graphics/FlutterDarwinExternalTextureMetal.h

@@ -0,0 +1,34 @@
+// 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 <Foundation/Foundation.h>
+#import <Metal/Metal.h>
+
+#import "flutter/shell/platform/darwin/common/framework/Headers/FlutterTexture.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/gpu/GrDirectContext.h"
+
+@interface FlutterDarwinExternalTextureMetal : NSObject
+
+- (nullable instancetype)initWithTextureCache:(nonnull CVMetalTextureCacheRef)textureCache
+                                    textureID:(int64_t)textureID
+                                      texture:(nonnull NSObject<FlutterTexture>*)texture;
+
+- (void)paint:(SkCanvas&)canvas
+       bounds:(const SkRect&)bounds
+       freeze:(BOOL)freeze
+    grContext:(nonnull GrDirectContext*)grContext
+     sampling:(const SkSamplingOptions&)sampling;
+
+- (void)onGrContextCreated;
+
+- (void)onGrContextDestroyed;
+
+- (void)markNewFrameAvailable;
+
+- (void)onTextureUnregistered;
+
+@property(nonatomic, readonly) int64_t textureID;
+
+@end