Optimize and refine the render texture code.

engine/src/flutter/shell/platform/embedder/BUILD.gn

@@ -177,9 +177,8 @@ template("embedder_source_set") {
         sources += [
           "embedder_surface_vulkan_impeller.cc",
           "embedder_surface_vulkan_impeller.h",
-          "embedder_external_texture_source_vulkan.cc",
-          "embedder_external_texture_source_vulkan.h",
         ]
+        deps += [ "//flutter/impeller/display_list" ]
       }
 
       deps += [
@@ -261,6 +260,8 @@ test_fixtures("fixtures") {
     "fixtures/gradient_metal.png",
     "fixtures/external_texture_impeller.png",
     "fixtures/external_texture_metal.png",
+    "fixtures/external_texture_nv12.png",
+    "fixtures/texture.nv12",
     "fixtures/gradient_xform.png",
     "fixtures/scene_without_custom_compositor.png",
     "fixtures/scene_without_custom_compositor_with_xform.png",

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

@@ -2398,9 +2398,10 @@ FlutterEngineResult FlutterEngineInitialize(size_t version,
       auto external_texture_vulkan_callback =
           [ptr = callback, user_data](
               int64_t texture_identifier, size_t width,
-              size_t height) -> std::unique_ptr<FlutterVulkanTexture> {
-        std::unique_ptr<FlutterVulkanTexture> texture =
-            std::make_unique<FlutterVulkanTexture>();
+              size_t height) -> std::unique_ptr<FlutterVulkanExternalTexture> {
+        std::unique_ptr<FlutterVulkanExternalTexture> texture =
+            std::make_unique<FlutterVulkanExternalTexture>();
+        texture->struct_size = sizeof(FlutterVulkanExternalTexture);
         if (!ptr(user_data, texture_identifier, width, height, texture.get())) {
           return nullptr;
         }

engine/src/flutter/shell/platform/embedder/embedder.h

@@ -930,9 +930,6 @@ typedef void* FlutterVulkanQueueHandle;
 /// Alias for VkImage.
 typedef uint64_t FlutterVulkanImageHandle;
 
-/// Alias for VkDeviceMemory.
-typedef uint64_t FlutterVulkanDeviceMemoryHandle;
-
 typedef struct {
   /// The size of this struct. Must be sizeof(FlutterVulkanImage).
   size_t struct_size;
@@ -962,25 +959,27 @@ typedef bool (*FlutterVulkanPresentCallback)(
     const FlutterVulkanImage* /* image */);
 
 typedef struct {
+  /// The size of this struct. Must be sizeof(FlutterVulkanExternalTexture).
+  size_t struct_size;
   /// Handle to the VkImage that is owned by the embedder. The engine will
-  /// bind this image for writing the frame.
+  /// sample from this image during composition. The VkImage must be in the
+  /// VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL layout when provided to the
+  /// engine.
   FlutterVulkanImageHandle image;
-  /// The VkDeviceMemory that backs the iamge.
-  FlutterVulkanDeviceMemoryHandle image_memory;
   /// The VkFormat of the image (for example: VK_FORMAT_R8G8B8A8_UNORM).
   uint32_t format;
   /// User data to be returned on the invocation of the destruction callback.
   void* user_data;
   /// Callback invoked (on an engine managed thread) that asks the embedder to
-  /// collect the texture.
+  /// collect the texture. This is optional and can be null.
   VoidCallback destruction_callback;
   /// Optional parameters for texture height/width, default is 0, non-zero means
   /// the texture has the specified width/height.
   /// Width of the texture.
   size_t width;
   /// Height of the texture.
   size_t height;
-} FlutterVulkanTexture;
+} FlutterVulkanExternalTexture;
 
 /// Callback to provide an external texture for a given texture_id.
 /// See: external_texture_frame_callback.
@@ -989,7 +988,7 @@ typedef bool (*FlutterVulkanTextureFrameCallback)(
     int64_t /* texture identifier */,
     size_t /* width */,
     size_t /* height */,
-    FlutterVulkanTexture* /* texture out */);
+    FlutterVulkanExternalTexture* /* texture out */);
 
 typedef struct {
   /// The size of this struct. Must be sizeof(FlutterVulkanRendererConfig).