Add platfrom surface buffer structor

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

@@ -33,8 +33,7 @@ namespace {
 // interface provided by the C API and the std::function-based message handler
 // interface of BinaryMessenger.
 void ForwardToHandler(FlutterDesktopMessengerRef messenger,
-                      const FlutterDesktopMessage* message,
-                      void* user_data) {
+                      const FlutterDesktopMessage* message, void* user_data) {
   auto* response_handle = message->response_handle;
   BinaryReply reply_handler = [messenger, response_handle](
                                   const uint8_t* reply,
@@ -67,8 +66,7 @@ BinaryMessengerImpl::BinaryMessengerImpl(
 BinaryMessengerImpl::~BinaryMessengerImpl() = default;
 
 void BinaryMessengerImpl::Send(const std::string& channel,
-                               const uint8_t* message,
-                               size_t message_size,
+                               const uint8_t* message, size_t message_size,
                                BinaryReply reply) const {
   if (reply == nullptr) {
     FlutterDesktopMessengerSend(messenger_, channel.c_str(), message,
@@ -169,6 +167,21 @@ int64_t TextureRegistrarImpl::RegisterTexture(TextureVariant* texture) {
       return buffer;
     };
 
+    int64_t texture_id = FlutterDesktopTextureRegistrarRegisterExternalTexture(
+        texture_registrar_ref_, &info);
+    return texture_id;
+  } else if (auto gpu_buffer_texture = std::get_if<GpuBufferTexture>(texture)) {
+    FlutterDesktopTextureInfo info = {};
+    info.type = kFlutterDesktopGpuBufferTexture;
+    info.pixel_buffer_config.user_data = gpu_buffer_texture;
+    info.pixel_buffer_config.gbCallback =
+        [](size_t width, size_t height,
+           void* user_data) -> const FlutterDesktopGpuBuffer* {
+      auto texture = static_cast<GpuBufferTexture*>(user_data);
+      auto buffer = texture->CopyGpuBuffer(width, height);
+      return buffer;
+    };
+
     int64_t texture_id = FlutterDesktopTextureRegistrarRegisterExternalTexture(
         texture_registrar_ref_, &info);
     return texture_id;

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

@@ -42,10 +42,39 @@ class PixelBufferTexture {
   const CopyBufferCallback copy_buffer_callback_;
 };
 
+// A pixel buffer texture.
+class GpuBufferTexture {
+ public:
+  // A callback used for retrieving pixel buffers.
+  typedef std::function<const FlutterDesktopGpuBuffer*(size_t width,
+                                                         size_t height)>
+      CopyBufferCallback;
+
+  // Creates a pixel buffer texture that uses the provided |copy_buffer_cb| to
+  // retrieve the buffer.
+  // As the callback is usually invoked from the render thread, the callee must
+  // take care of proper synchronization. It also needs to be ensured that the
+  // returned buffer isn't released prior to unregistering this texture.
+  GpuBufferTexture(CopyBufferCallback copy_buffer_callback)
+      : copy_buffer_callback_(copy_buffer_callback) {}
+
+  // Returns the callback-provided FlutterDesktopPixelBuffer that contains the
+  // actual pixel data. The intended surface size is specified by |width| and
+  // |height|.
+  const FlutterDesktopGpuBuffer* CopyGpuBuffer(size_t width,
+                                                   size_t height) const {
+    return copy_buffer_callback_(width, height);
+  }
+
+ private:
+  const CopyBufferCallback copy_buffer_callback_;
+};
+
+
 // The available texture variants.
 // Only PixelBufferTexture is currently implemented.
 // Other variants are expected to be added in the future.
-typedef std::variant<PixelBufferTexture> TextureVariant;
+typedef std::variant<PixelBufferTexture, GpuBufferTexture> TextureVariant;
 
 // An object keeping track of external textures.
 //

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

@@ -23,7 +23,8 @@ typedef struct FlutterDesktopTextureRegistrar*
 // Additional types may be added in the future.
 typedef enum {
   // A Pixel buffer-based texture.
-  kFlutterDesktopPixelBufferTexture
+  kFlutterDesktopPixelBufferTexture,
+  kFlutterDesktopGpuBufferTexture
 } FlutterDesktopTextureType;
 
 // An image buffer object.
@@ -36,6 +37,17 @@ typedef struct {
   size_t height;
 } FlutterDesktopPixelBuffer;
 
+// An image buffer object.
+typedef struct {
+  // The pixel data buffer.
+  const void* buffer;
+  // Width of the pixel buffer.
+  size_t width;
+  // Height of the pixel buffer.
+  size_t height;
+} FlutterDesktopGpuBuffer;
+
+
 // The pixel buffer copy callback definition provided to
 // the Flutter engine to copy the texture.
 // It is invoked with the intended surface size specified by |width| and
@@ -49,11 +61,18 @@ typedef const FlutterDesktopPixelBuffer* (
     *FlutterDesktopPixelBufferTextureCallback)(size_t width,
                                                size_t height,
                                                void* user_data);
+typedef const FlutterDesktopGpuBuffer* (
+    *FlutterDesktopGpuBufferTextureCallback)(size_t width,
+                                               size_t height,
+                                               void* user_data);
+
 
 // An object used to configure pixel buffer textures.
 typedef struct {
   // The callback used by the engine to copy the pixel buffer object.
   FlutterDesktopPixelBufferTextureCallback callback;
+
+  FlutterDesktopGpuBufferTextureCallback gbCallback;
   // Opaque data that will get passed to the provided |callback|.
   void* user_data;
 } FlutterDesktopPixelBufferTextureConfig;