Add windows plugin texture support

Author: jnschulze

ci/licenses_golden/licenses_flutter

@@ -830,6 +830,7 @@ FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/include/flutter/
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/include/flutter/plugin_registry.h
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/include/flutter/standard_message_codec.h
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/include/flutter/standard_method_codec.h
+FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/include/flutter/texture_registrar.h
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/method_call_unittests.cc
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/method_channel_unittests.cc
 FILE: ../../../flutter/shell/platform/common/cpp/client_wrapper/method_result_functions_unittests.cc
@@ -853,6 +854,7 @@ FILE: ../../../flutter/shell/platform/common/cpp/path_utils_unittests.cc
 FILE: ../../../flutter/shell/platform/common/cpp/public/flutter_export.h
 FILE: ../../../flutter/shell/platform/common/cpp/public/flutter_messenger.h
 FILE: ../../../flutter/shell/platform/common/cpp/public/flutter_plugin_registrar.h
+FILE: ../../../flutter/shell/platform/common/cpp/public/flutter_texture_registrar.h
 FILE: ../../../flutter/shell/platform/common/cpp/text_input_model.cc
 FILE: ../../../flutter/shell/platform/common/cpp/text_input_model.h
 FILE: ../../../flutter/shell/platform/common/cpp/text_input_model_unittests.cc
@@ -1301,6 +1303,8 @@ FILE: ../../../flutter/shell/platform/windows/client_wrapper/plugin_registrar_wi
 FILE: ../../../flutter/shell/platform/windows/dpi_utils.cc
 FILE: ../../../flutter/shell/platform/windows/dpi_utils.h
 FILE: ../../../flutter/shell/platform/windows/dpi_utils_unittests.cc
+FILE: ../../../flutter/shell/platform/windows/external_texture_gl.cc
+FILE: ../../../flutter/shell/platform/windows/external_texture_gl.h
 FILE: ../../../flutter/shell/platform/windows/flutter_windows.cc
 FILE: ../../../flutter/shell/platform/windows/key_event_handler.cc
 FILE: ../../../flutter/shell/platform/windows/key_event_handler.h

shell/platform/common/cpp/BUILD.gn

@@ -12,6 +12,7 @@ _public_headers = [
   "public/flutter_export.h",
   "public/flutter_messenger.h",
   "public/flutter_plugin_registrar.h",
+  "public/flutter_texture_registrar.h",
 ]
 
 # Any files that are built by clients (client_wrapper code, library headers for

shell/platform/common/cpp/client_wrapper/core_wrapper_files.gni

@@ -20,6 +20,7 @@ core_cpp_client_wrapper_includes =
                     "include/flutter/method_result.h",
                     "include/flutter/plugin_registrar.h",
                     "include/flutter/plugin_registry.h",
+                    "include/flutter/texture_registrar.h",
                     "include/flutter/standard_message_codec.h",
                     "include/flutter/standard_method_codec.h",
                   ],

shell/platform/common/cpp/client_wrapper/include/flutter/plugin_registrar.h

@@ -13,6 +13,7 @@
 #include <flutter_plugin_registrar.h>
 
 #include "binary_messenger.h"
+#include "texture_registrar.h"
 
 namespace flutter {
 
@@ -41,6 +42,10 @@ class PluginRegistrar {
   // This pointer will remain valid for the lifetime of this instance.
   BinaryMessenger* messenger() { return messenger_.get(); }
 
+  // Returns the texture registrar to use for the plugin to render a pixel
+  // buffer.
+  TextureRegistrar* textures() { return textures_.get(); }
+
   // Takes ownership of |plugin|.
   //
   // Plugins are not required to call this method if they have other lifetime
@@ -60,6 +65,8 @@ class PluginRegistrar {
 
   std::unique_ptr<BinaryMessenger> messenger_;
 
+  std::unique_ptr<TextureRegistrar> textures_;
+
   // Plugins registered for ownership.
   std::set<std::unique_ptr<Plugin>> plugins_;
 };

shell/platform/common/cpp/client_wrapper/include/flutter/texture_registrar.h

@@ -0,0 +1,49 @@
+// 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.
+
+#ifndef FLUTTER_SHELL_PLATFORM_COMMON_CPP_CLIENT_WRAPPER_INCLUDE_FLUTTER_TEXTURE_REGISTRAR_H_
+#define FLUTTER_SHELL_PLATFORM_COMMON_CPP_CLIENT_WRAPPER_INCLUDE_FLUTTER_TEXTURE_REGISTRAR_H_
+
+#include <flutter_texture_registrar.h>
+
+#include <stdint.h>
+#include <memory>
+
+namespace flutter {
+
+// An external texture interface declaration.
+class Texture {
+ public:
+  virtual ~Texture() {}
+  // This interface is used to respond to texture copy requests from the Flutter
+  // engine, Flutter engine will be providing the |height| and |width|
+  // parameters of bounds. In some cases, the user can be scale the texture to
+  // the size of the bounds to reduce memory usage.
+  virtual const PixelBuffer* CopyPixelBuffer(size_t width, size_t height) = 0;
+};
+
+class TextureRegistrar {
+ public:
+  virtual ~TextureRegistrar() {}
+
+  /**
+   * Registers a |texture| object and returns the ID for that texture.
+   */
+  virtual int64_t RegisterTexture(Texture* texture) = 0;
+
+  /**
+   * Notify the flutter engine that the texture object corresponding
+   * to |texure_id| needs to render a new texture.
+   */
+  virtual void MarkTextureFrameAvailable(int64_t texture_id) = 0;
+
+  /**
+   * Unregisters an existing Texture object.
+   */
+  virtual void UnregisterTexture(int64_t texture_id) = 0;
+};
+
+}  // namespace flutter
+
+#endif  // FLUTTER_SHELL_PLATFORM_COMMON_CPP_CLIENT_WRAPPER_INCLUDE_FLUTTER_TEXTURE_REGISTRAR_H_

shell/platform/common/cpp/client_wrapper/plugin_registrar.cc

@@ -126,12 +126,52 @@ void BinaryMessengerImpl::SetMessageHandler(const std::string& channel,
                                      ForwardToHandler, message_handler);
 }
 
+// Wrapper around a FlutterDesktopTextureRegistrarRef that implements the
+// TextureRegistrar API.
+class TextureRegistrarImpl : public TextureRegistrar {
+ public:
+  explicit TextureRegistrarImpl(
+      FlutterDesktopTextureRegistrarRef texture_registrar_ref)
+      : texture_registrar_ref_(texture_registrar_ref) {}
+
+  virtual ~TextureRegistrarImpl() = default;
+
+  // Prevent copying.
+  TextureRegistrarImpl(TextureRegistrarImpl const&) = delete;
+  TextureRegistrarImpl& operator=(TextureRegistrarImpl const&) = delete;
+
+  virtual int64_t RegisterTexture(Texture* texture) override {
+    FlutterTextureCallback callback =
+        [](size_t width, size_t height, void* user_data) -> const PixelBuffer* {
+      return static_cast<Texture*>(user_data)->CopyPixelBuffer(width, height);
+    };
+    int64_t texture_id = FlutterDesktopRegisterExternalTexture(
+        texture_registrar_ref_, callback, texture);
+    return texture_id;
+  }
+
+  virtual void MarkTextureFrameAvailable(int64_t texture_id) override {
+    FlutterDesktopMarkExternalTextureFrameAvailable(texture_registrar_ref_,
+                                                    texture_id);
+  }
+
+  virtual void UnregisterTexture(int64_t texture_id) override {
+    FlutterDesktopUnregisterExternalTexture(texture_registrar_ref_, texture_id);
+  }
+
+ private:
+  // Handle for interacting with the C API.
+  FlutterDesktopTextureRegistrarRef texture_registrar_ref_;
+};
+
 // ===== PluginRegistrar =====
 
 PluginRegistrar::PluginRegistrar(FlutterDesktopPluginRegistrarRef registrar)
     : registrar_(registrar) {
   auto core_messenger = FlutterDesktopRegistrarGetMessenger(registrar_);
   messenger_ = std::make_unique<BinaryMessengerImpl>(core_messenger);
+  auto texture_registrar = FlutterDesktopGetTextureRegistrar(registrar_);
+  textures_ = std::make_unique<TextureRegistrarImpl>(texture_registrar);
 }
 
 PluginRegistrar::~PluginRegistrar() {}

shell/platform/common/cpp/client_wrapper/plugin_registrar_unittests.cc

@@ -2,10 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <map>
 #include <memory>
 #include <vector>
 
 #include "flutter/shell/platform/common/cpp/client_wrapper/include/flutter/plugin_registrar.h"
+#include "flutter/shell/platform/common/cpp/client_wrapper/include/flutter/texture_registrar.h"
 #include "flutter/shell/platform/common/cpp/client_wrapper/testing/stub_flutter_api.h"
 #include "gtest/gtest.h"
 
@@ -15,6 +17,14 @@ namespace {
 
 // Stub implementation to validate calls to the API.
 class TestApi : public testing::StubFlutterApi {
+ public:
+  struct FakeTexture {
+    int64_t texture_id;
+    int32_t mark_count;
+    FlutterTextureCallback texture_callback;
+    void* user_data;
+  };
+
  public:
   // |flutter::testing::StubFlutterApi|
   bool MessengerSend(const char* channel,
@@ -52,10 +62,55 @@ class TestApi : public testing::StubFlutterApi {
     return last_destruction_callback_set_;
   }
 
+  int64_t RegisterExternalTexture(FlutterTextureCallback texture_callback,
+                                  void* user_data) override {
+    last_texture_id_++;
+
+    auto texture = std::make_unique<FakeTexture>();
+    texture->texture_callback = texture_callback;
+    texture->user_data = user_data;
+    texture->mark_count = 0;
+    texture->texture_id = last_texture_id_;
+
+    textures_[last_texture_id_] = std::move(texture);
+    return last_texture_id_;
+  }
+
+  bool UnregisterExternalTexture(int64_t texture_id) override {
+    auto it = textures_.find(texture_id);
+    if (it != textures_.end()) {
+      textures_.erase(it);
+      return true;
+    }
+    return false;
+  }
+
+  bool TextureFrameAvailable(int64_t texture_id) override {
+    auto it = textures_.find(texture_id);
+    if (it != textures_.end()) {
+      it->second->mark_count++;
+      return true;
+    }
+    return false;
+  }
+
+  FakeTexture* GetFakeTexture(int64_t texture_id) {
+    auto it = textures_.find(texture_id);
+    if (it != textures_.end())
+      return it->second.get();
+    return nullptr;
+  }
+
+  int64_t last_texture_id() { return last_texture_id_; }
+
+  size_t textures_size() { return textures_.size(); }
+
  private:
   const uint8_t* last_data_sent_ = nullptr;
   FlutterDesktopMessageCallback last_message_callback_set_ = nullptr;
   FlutterDesktopOnRegistrarDestroyed last_destruction_callback_set_ = nullptr;
+  int64_t last_texture_id_ = -1;
+  std::map<int64_t, std::unique_ptr<FakeTexture>> textures_;
 };
 
 // A PluginRegistrar whose destruction can be watched for by tests.
@@ -179,4 +234,37 @@ TEST(PluginRegistrarTest, ManagerRemovesOnDestruction) {
             nullptr);
 }
 
+// Tests texture register that calls through to the C API.
+TEST(MethodCallTest, RegisterTexture) {
+  testing::ScopedStubFlutterApi scoped_api_stub(std::make_unique<TestApi>());
+  auto test_api = static_cast<TestApi*>(scoped_api_stub.stub());
+
+  auto dummy_registrar_handle =
+      reinterpret_cast<FlutterDesktopPluginRegistrarRef>(1);
+  PluginRegistrar registrar(dummy_registrar_handle);
+  TextureRegistrar* textures = registrar.textures();
+
+  EXPECT_EQ(test_api->last_texture_id(), -1);
+  auto texture = test_api->GetFakeTexture(0);
+  EXPECT_EQ(texture, nullptr);
+
+  int64_t texture_id = textures->RegisterTexture(reinterpret_cast<Texture*>(2));
+  EXPECT_EQ(test_api->last_texture_id(), texture_id);
+  EXPECT_EQ(test_api->textures_size(), static_cast<size_t>(1));
+
+  texture = test_api->GetFakeTexture(texture_id);
+  EXPECT_EQ(texture->texture_id, texture_id);
+  EXPECT_EQ(texture->user_data, reinterpret_cast<Texture*>(2));
+
+  textures->MarkTextureFrameAvailable(texture_id);
+  textures->MarkTextureFrameAvailable(texture_id);
+  textures->MarkTextureFrameAvailable(texture_id);
+  EXPECT_EQ(texture->mark_count, 3);
+
+  textures->UnregisterTexture(texture_id);
+  texture = test_api->GetFakeTexture(texture_id);
+  EXPECT_EQ(texture, nullptr);
+  EXPECT_EQ(test_api->textures_size(), static_cast<size_t>(0));
+}
+
 }  // namespace flutter

shell/platform/common/cpp/client_wrapper/testing/stub_flutter_api.cc

@@ -104,3 +104,40 @@ void FlutterDesktopMessengerSetCallback(FlutterDesktopMessengerRef messenger,
     s_stub_implementation->MessengerSetCallback(channel, callback, user_data);
   }
 }
+
+FlutterDesktopTextureRegistrarRef FlutterDesktopGetTextureRegistrar(
+    FlutterDesktopPluginRegistrarRef registrar) {
+  return reinterpret_cast<FlutterDesktopTextureRegistrarRef>(1);
+}
+
+int64_t FlutterDesktopRegisterExternalTexture(
+    FlutterDesktopTextureRegistrarRef texture_registrar,
+    FlutterTextureCallback texture_callback,
+    void* user_data) {
+  uint64_t result = -1;
+  if (s_stub_implementation) {
+    result = s_stub_implementation->RegisterExternalTexture(texture_callback,
+                                                            user_data);
+  }
+  return result;
+}
+
+bool FlutterDesktopUnregisterExternalTexture(
+    FlutterDesktopTextureRegistrarRef texture_registrar,
+    int64_t texture_id) {
+  bool result = false;
+  if (s_stub_implementation) {
+    result = s_stub_implementation->UnregisterExternalTexture(texture_id);
+  }
+  return result;
+}
+
+bool FlutterDesktopMarkExternalTextureFrameAvailable(
+    FlutterDesktopTextureRegistrarRef texture_registrar,
+    int64_t texture_id) {
+  bool result = false;
+  if (s_stub_implementation) {
+    result = s_stub_implementation->TextureFrameAvailable(texture_id);
+  }
+  return result;
+}

shell/platform/common/cpp/client_wrapper/testing/stub_flutter_api.h

@@ -67,6 +67,19 @@ class StubFlutterApi {
   virtual void MessengerSetCallback(const char* channel,
                                     FlutterDesktopMessageCallback callback,
                                     void* user_data) {}
+
+  // Called for FlutterDesktopRegisterExternalTexture.
+  virtual int64_t RegisterExternalTexture(
+      FlutterTextureCallback texture_callback,
+      void* user_data) {
+    return -1;
+  }
+
+  // Called for FlutterDesktopUnregisterExternalTexture.
+  virtual bool UnregisterExternalTexture(int64_t texture_id) { return false; }
+
+  // Called for FlutterDesktopMarkExternalTextureFrameAvailable.
+  virtual bool TextureFrameAvailable(int64_t texture_id) { return false; }
 };
 
 // A test helper that owns a stub implementation, making it the test stub for

shell/platform/common/cpp/public/flutter_plugin_registrar.h

@@ -10,6 +10,7 @@
 
 #include "flutter_export.h"
 #include "flutter_messenger.h"
+#include "flutter_texture_registrar.h"
 
 #if defined(__cplusplus)
 extern "C" {
@@ -26,6 +27,10 @@ typedef void (*FlutterDesktopOnRegistrarDestroyed)(
 FLUTTER_EXPORT FlutterDesktopMessengerRef
 FlutterDesktopRegistrarGetMessenger(FlutterDesktopPluginRegistrarRef registrar);
 
+// Returns the texture registrar associated with this registrar.
+FLUTTER_EXPORT FlutterDesktopTextureRegistrarRef
+FlutterDesktopGetTextureRegistrar(FlutterDesktopPluginRegistrarRef registrar);
+
 // Registers a callback to be called when the plugin registrar is destroyed.
 FLUTTER_EXPORT void FlutterDesktopRegistrarSetDestructionHandler(
     FlutterDesktopPluginRegistrarRef registrar,