reland of https://github.com/flutter/engine/pull/23634 (flutter/engine#23865)

engine/src/flutter/shell/gpu/gpu_surface_gl.cc

@@ -34,16 +34,13 @@ static const int kGrCacheMaxCount = 8192;
 // system channel.
 static const size_t kGrCacheMaxByteSize = 24 * (1 << 20);
 
-GPUSurfaceGL::GPUSurfaceGL(GPUSurfaceGLDelegate* delegate,
-                           bool render_to_surface)
-    : delegate_(delegate),
-      render_to_surface_(render_to_surface),
-      weak_factory_(this) {
-  auto context_switch = delegate_->GLContextMakeCurrent();
+sk_sp<GrDirectContext> GPUSurfaceGL::MakeGLContext(
+    GPUSurfaceGLDelegate* delegate) {
+  auto context_switch = delegate->GLContextMakeCurrent();
   if (!context_switch->GetResult()) {
     FML_LOG(ERROR)
         << "Could not make the context current to setup the gr context.";
-    return;
+    return nullptr;
   }
 
   GrContextOptions options;
@@ -64,32 +61,31 @@ GPUSurfaceGL::GPUSurfaceGL(GPUSurfaceGLDelegate* delegate,
   // TODO(goderbauer): remove option when skbug.com/7523 is fixed.
   // A similar work-around is also used in shell/common/io_manager.cc.
   options.fDisableGpuYUVConversion = true;
+  auto context = GrDirectContext::MakeGL(delegate->GetGLInterface(), options);
 
-  auto context = GrDirectContext::MakeGL(delegate_->GetGLInterface(), options);
-
-  if (context == nullptr) {
+  if (!context) {
     FML_LOG(ERROR) << "Failed to setup Skia Gr context.";
-    return;
+    return nullptr;
   }
 
-  context_ = std::move(context);
-
-  context_->setResourceCacheLimits(kGrCacheMaxCount, kGrCacheMaxByteSize);
-
-  context_owner_ = true;
-
-  valid_ = true;
+  context->setResourceCacheLimits(kGrCacheMaxCount, kGrCacheMaxByteSize);
 
   std::vector<PersistentCache::SkSLCache> caches =
       PersistentCache::GetCacheForProcess()->LoadSkSLs();
   int compiled_count = 0;
   for (const auto& cache : caches) {
-    compiled_count += context_->precompileShader(*cache.first, *cache.second);
+    compiled_count += context->precompileShader(*cache.first, *cache.second);
   }
   FML_LOG(INFO) << "Found " << caches.size() << " SkSL shaders; precompiled "
                 << compiled_count;
 
-  delegate_->GLContextClearCurrent();
+  return context;
+}
+
+GPUSurfaceGL::GPUSurfaceGL(GPUSurfaceGLDelegate* delegate,
+                           bool render_to_surface)
+    : GPUSurfaceGL(MakeGLContext(delegate), delegate, render_to_surface) {
+  context_owner_ = true;
 }
 
 GPUSurfaceGL::GPUSurfaceGL(sk_sp<GrDirectContext> gr_context,
@@ -97,6 +93,7 @@ GPUSurfaceGL::GPUSurfaceGL(sk_sp<GrDirectContext> gr_context,
                            bool render_to_surface)
     : delegate_(delegate),
       context_(gr_context),
+      context_owner_(false),
       render_to_surface_(render_to_surface),
       weak_factory_(this) {
   auto context_switch = delegate_->GLContextMakeCurrent();
@@ -108,8 +105,7 @@ GPUSurfaceGL::GPUSurfaceGL(sk_sp<GrDirectContext> gr_context,
 
   delegate_->GLContextClearCurrent();
 
-  valid_ = true;
-  context_owner_ = false;
+  valid_ = gr_context != nullptr;
 }
 
 GPUSurfaceGL::~GPUSurfaceGL() {

engine/src/flutter/shell/gpu/gpu_surface_gl.h

@@ -20,6 +20,8 @@ namespace flutter {
 
 class GPUSurfaceGL : public Surface {
  public:
+  static sk_sp<GrDirectContext> MakeGLContext(GPUSurfaceGLDelegate* delegate);
+
   GPUSurfaceGL(GPUSurfaceGLDelegate* delegate, bool render_to_surface);
 
   // Creates a new GL surface reusing an existing GrDirectContext.
@@ -53,13 +55,13 @@ class GPUSurfaceGL : public Surface {
   sk_sp<GrDirectContext> context_;
   sk_sp<SkSurface> onscreen_surface_;
   /// FBO backing the current `onscreen_surface_`.
-  uint32_t fbo_id_;
-  bool context_owner_;
+  uint32_t fbo_id_ = 0;
+  bool context_owner_ = false;
   // TODO(38466): Refactor GPU surface APIs take into account the fact that an
   // external view embedder may want to render to the root surface. This is a
   // hack to make avoid allocating resources for the root surface when an
   // external view embedder is present.
-  const bool render_to_surface_;
+  const bool render_to_surface_ = true;
   bool valid_ = false;
   fml::TaskRunnerAffineWeakPtrFactory<GPUSurfaceGL> weak_factory_;
 

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterEngineTest_mrc.mm

@@ -33,10 +33,8 @@ FLUTTER_ASSERT_NOT_ARC
   std::shared_ptr<flutter::IOSContext> engine_context = [engine iosPlatformView]->GetIosContext();
   std::shared_ptr<flutter::IOSContext> spawn_context = [spawn iosPlatformView]->GetIosContext();
   XCTAssertEqual(engine_context, spawn_context);
-  // If this assert fails it means we may be using the software or OpenGL
-  // renderer when we were expecting Metal.  For software rendering, this is
-  // expected to be nullptr.  For OpenGL, implementing this is an outstanding
-  // change see https://github.com/flutter/flutter/issues/73744.
+  // If this assert fails it means we may be using the software.  For software rendering, this is
+  // expected to be nullptr.
   XCTAssertTrue(engine_context->GetMainContext() != nullptr);
   XCTAssertEqual(engine_context->GetMainContext(), spawn_context->GetMainContext());
   [engine release];

engine/src/flutter/shell/platform/darwin/ios/ios_context_gl.h

@@ -25,16 +25,11 @@ class IOSContextGL final : public IOSContext {
 
   std::unique_ptr<IOSRenderTargetGL> CreateRenderTarget(fml::scoped_nsobject<CAEAGLLayer> layer);
 
- private:
-  fml::scoped_nsobject<EAGLContext> context_;
-  fml::scoped_nsobject<EAGLContext> resource_context_;
+  void SetMainContext(const sk_sp<GrDirectContext>& main_context);
 
   // |IOSContext|
   sk_sp<GrDirectContext> CreateResourceContext() override;
 
-  // |IOSContext|
-  sk_sp<GrDirectContext> GetMainContext() const override;
-
   // |IOSContext|
   std::unique_ptr<GLContextResult> MakeCurrent() override;
 
@@ -43,6 +38,14 @@ class IOSContextGL final : public IOSContext {
       int64_t texture_id,
       fml::scoped_nsobject<NSObject<FlutterTexture>> texture) override;
 
+  // |IOSContext|
+  sk_sp<GrDirectContext> GetMainContext() const override;
+
+ private:
+  fml::scoped_nsobject<EAGLContext> context_;
+  fml::scoped_nsobject<EAGLContext> resource_context_;
+  sk_sp<GrDirectContext> main_context_;
+
   FML_DISALLOW_COPY_AND_ASSIGN(IOSContextGL);
 };
 

engine/src/flutter/shell/platform/darwin/ios/ios_context_gl.mm

@@ -7,6 +7,7 @@
 #import <OpenGLES/EAGL.h>
 
 #include "flutter/shell/common/shell_io_manager.h"
+#include "flutter/shell/gpu/gpu_surface_gl.h"
 #include "flutter/shell/gpu/gpu_surface_gl_delegate.h"
 #import "flutter/shell/platform/darwin/ios/ios_external_texture_gl.h"
 
@@ -24,7 +25,11 @@ IOSContextGL::IOSContextGL() {
   }
 }
 
-IOSContextGL::~IOSContextGL() = default;
+IOSContextGL::~IOSContextGL() {
+  if (main_context_) {
+    main_context_->releaseResourcesAndAbandonContext();
+  }
+}
 
 std::unique_ptr<IOSRenderTargetGL> IOSContextGL::CreateRenderTarget(
     fml::scoped_nsobject<CAEAGLLayer> layer) {
@@ -45,12 +50,11 @@ sk_sp<GrDirectContext> IOSContextGL::CreateResourceContext() {
 
 // |IOSContext|
 sk_sp<GrDirectContext> IOSContextGL::GetMainContext() const {
-  /// TODO(73744): Currently the GPUSurfaceGL creates the main context for
-  /// OpenGL.  With Metal the IOSContextMetal creates the main context and is
-  /// shared across surfaces.  We should refactor the OpenGL Context/Surfaces to
-  /// behave like the Metal equivalents.  Until then engines in the same group
-  /// will have a heavier memory cost if they are using OpenGL.
-  return nullptr;
+  return main_context_;
+}
+
+void IOSContextGL::SetMainContext(const sk_sp<GrDirectContext>& main_context) {
+  main_context_ = main_context;
 }
 
 // |IOSContext|

engine/src/flutter/shell/platform/darwin/ios/ios_surface_gl.mm

@@ -38,8 +38,16 @@ void IOSSurfaceGL::UpdateStorageSizeIfNecessary() {
 std::unique_ptr<Surface> IOSSurfaceGL::CreateGPUSurface(GrDirectContext* gr_context) {
   if (gr_context) {
     return std::make_unique<GPUSurfaceGL>(sk_ref_sp(gr_context), this, true);
+  } else {
+    IOSContextGL* gl_context = CastToGLContext(GetContext());
+    sk_sp<GrDirectContext> context = gl_context->GetMainContext();
+    if (!context) {
+      context = GPUSurfaceGL::MakeGLContext(this);
+      gl_context->SetMainContext(context);
+    }
+
+    return std::make_unique<GPUSurfaceGL>(context, this, true);
   }
-  return std::make_unique<GPUSurfaceGL>(this, true);
 }
 
 // |GPUSurfaceGLDelegate|

engine/src/flutter/shell/platform/darwin/ios/ios_surface_metal.mm

@@ -40,10 +40,10 @@ void IOSSurfaceMetal::UpdateStorageSizeIfNecessary() {
 }
 
 // |IOSSurface|
-std::unique_ptr<Surface> IOSSurfaceMetal::CreateGPUSurface(GrDirectContext* /* unused */) {
-  auto metal_context = CastToMetalContext(GetContext());
-  return std::make_unique<GPUSurfaceMetal>(this,                            // layer
-                                           metal_context->GetMainContext()  // context
+std::unique_ptr<Surface> IOSSurfaceMetal::CreateGPUSurface(GrDirectContext* context) {
+  FML_DCHECK(context);
+  return std::make_unique<GPUSurfaceMetal>(this,               // layer
+                                           sk_ref_sp(context)  // context
   );
 }
 

engine/src/flutter/shell/platform/darwin/ios/platform_view_ios.mm

@@ -148,7 +148,7 @@ std::unique_ptr<Surface> PlatformViewIOS::CreateRenderingSurface() {
                       "has no ViewController.";
     return nullptr;
   }
-  return ios_surface_->CreateGPUSurface();
+  return ios_surface_->CreateGPUSurface(ios_context_->GetMainContext().get());
 }
 
 // |PlatformView|

engine/src/flutter/shell/platform/embedder/embedder_surface_gl.cc

@@ -80,7 +80,6 @@ std::unique_ptr<Surface> EmbedderSurfaceGL::CreateGPUSurface() {
   const bool render_to_surface = !external_view_embedder_;
   return std::make_unique<GPUSurfaceGL>(this,  // GPU surface GL delegate
                                         render_to_surface  // render to surface
-
   );
 }