[Impeller] Sync presentation when rendering into FlutterImageView. (flutter/engine#44881)

Fixes https://github.com/flutter/flutter/issues/131730

When the Android embedder starts rendering into a FlutterImageView, notify the Impeller context to block on submitKHR.

engine/src/flutter/impeller/renderer/backend/vulkan/context_vk.h

@@ -83,6 +83,11 @@ class ContextVK final : public Context,
   // |Context|
   void Shutdown() override;
 
+  // |Context|
+  void SetSyncPresentation(bool value) override { sync_presentation_ = value; }
+
+  bool GetSyncPresentation() const { return sync_presentation_; }
+
   void SetOffscreenFormat(PixelFormat pixel_format);
 
   template <typename T>
@@ -161,6 +166,7 @@ class ContextVK final : public Context,
   std::shared_ptr<ResourceManagerVK> resource_manager_;
   std::string device_name_;
   std::shared_ptr<fml::ConcurrentMessageLoop> raster_message_loop_;
+  bool sync_presentation_ = false;
   const uint64_t hash_;
 
   bool is_valid_ = false;

engine/src/flutter/impeller/renderer/backend/vulkan/surface_context_vk.cc

@@ -81,6 +81,10 @@ std::unique_ptr<Surface> SurfaceContextVK::AcquireNextSurface() {
   return surface;
 }
 
+void SurfaceContextVK::SetSyncPresentation(bool value) {
+  parent_->SetSyncPresentation(value);
+}
+
 #ifdef FML_OS_ANDROID
 
 vk::UniqueSurfaceKHR SurfaceContextVK::CreateAndroidSurface(

engine/src/flutter/impeller/renderer/backend/vulkan/surface_context_vk.h

@@ -54,6 +54,9 @@ class SurfaceContextVK : public Context,
   // |Context|
   void Shutdown() override;
 
+  // |Context|
+  void SetSyncPresentation(bool value) override;
+
   [[nodiscard]] bool SetWindowSurface(vk::UniqueSurfaceKHR surface);
 
   std::unique_ptr<Surface> AcquireNextSurface();

engine/src/flutter/impeller/renderer/backend/vulkan/swapchain_impl_vk.cc

@@ -465,48 +465,51 @@ bool SwapchainImplVK::Present(const std::shared_ptr<SwapchainImageVK>& image,
     }
   }
 
-  context.GetConcurrentWorkerTaskRunner()->PostTask(
-      [&, index, image, current_frame = current_frame_] {
-        auto context_strong = context_.lock();
-        if (!context_strong) {
-          return;
-        }
+  auto task = [&, index, image, current_frame = current_frame_] {
+    auto context_strong = context_.lock();
+    if (!context_strong) {
+      return;
+    }
 
-        const auto& sync = synchronizers_[current_frame];
+    const auto& sync = synchronizers_[current_frame];
 
-        //----------------------------------------------------------------------------
-        /// Present the image.
-        ///
-        uint32_t indices[] = {static_cast<uint32_t>(index)};
+    //----------------------------------------------------------------------------
+    /// Present the image.
+    ///
+    uint32_t indices[] = {static_cast<uint32_t>(index)};
 
-        vk::PresentInfoKHR present_info;
-        present_info.setSwapchains(*swapchain_);
-        present_info.setImageIndices(indices);
-        present_info.setWaitSemaphores(*sync->present_ready);
+    vk::PresentInfoKHR present_info;
+    present_info.setSwapchains(*swapchain_);
+    present_info.setImageIndices(indices);
+    present_info.setWaitSemaphores(*sync->present_ready);
 
-        switch (auto result = present_queue_.presentKHR(present_info)) {
-          case vk::Result::eErrorOutOfDateKHR:
-            // Caller will recreate the impl on acquisition, not submission.
-            [[fallthrough]];
-          case vk::Result::eErrorSurfaceLostKHR:
-            // Vulkan guarantees that the set of queue operations will still
-            // complete successfully.
-            [[fallthrough]];
-          case vk::Result::eSuboptimalKHR:
-            // Even though we're handling rotation changes via polling, we
-            // still need to handle the case where the swapchain signals that
-            // it's suboptimal (i.e. every frame when we are rotated given we
-            // aren't doing Vulkan pre-rotation).
-            [[fallthrough]];
-          case vk::Result::eSuccess:
-            return;
-          default:
-            VALIDATION_LOG << "Could not present queue: "
-                           << vk::to_string(result);
-            return;
-        }
-        FML_UNREACHABLE();
-      });
+    switch (auto result = present_queue_.presentKHR(present_info)) {
+      case vk::Result::eErrorOutOfDateKHR:
+        // Caller will recreate the impl on acquisition, not submission.
+        [[fallthrough]];
+      case vk::Result::eErrorSurfaceLostKHR:
+        // Vulkan guarantees that the set of queue operations will still
+        // complete successfully.
+        [[fallthrough]];
+      case vk::Result::eSuboptimalKHR:
+        // Even though we're handling rotation changes via polling, we
+        // still need to handle the case where the swapchain signals that
+        // it's suboptimal (i.e. every frame when we are rotated given we
+        // aren't doing Vulkan pre-rotation).
+        [[fallthrough]];
+      case vk::Result::eSuccess:
+        return;
+      default:
+        VALIDATION_LOG << "Could not present queue: " << vk::to_string(result);
+        return;
+    }
+    FML_UNREACHABLE();
+  };
+  if (context.GetSyncPresentation()) {
+    task();
+  } else {
+    context.GetConcurrentWorkerTaskRunner()->PostTask(task);
+  }
   return true;
 }
 

engine/src/flutter/impeller/renderer/context.h

@@ -161,6 +161,15 @@ class Context {
   ///
   virtual void Shutdown() = 0;
 
+  //----------------------------------------------------------------------------
+  /// @brief      Force the Vulkan presentation (submitKHR) to be performed on
+  ///             the raster task runner.
+  ///
+  ///             This is required for correct rendering on Android when using
+  ///             the hybrid composition mode. This has no effect on other
+  ///             backends.
+  virtual void SetSyncPresentation(bool value) {}
+
   //----------------------------------------------------------------------------
   /// @brief Accessor for a pool of HostBuffers.
   Pool<HostBuffer>& GetHostBufferPool() const { return host_buffer_pool_; }

engine/src/flutter/shell/platform/android/android_shell_holder.cc

@@ -347,4 +347,8 @@ void AndroidShellHolder::UpdateDisplayMetrics() {
   shell_->OnDisplayUpdates(std::move(displays));
 }
 
+void AndroidShellHolder::SetIsRenderingToImageView(bool value) {
+  platform_view_->SetIsRenderingToImageView(value);
+}
+
 }  // namespace flutter

engine/src/flutter/shell/platform/android/android_shell_holder.h

@@ -105,6 +105,8 @@ class AndroidShellHolder {
 
   void UpdateDisplayMetrics();
 
+  void SetIsRenderingToImageView(bool value);
+
  private:
   const flutter::Settings settings_;
   const std::shared_ptr<PlatformViewAndroidJNI> jni_facade_;

engine/src/flutter/shell/platform/android/io/flutter/embedding/android/FlutterImageView.java

@@ -143,6 +143,7 @@ public class FlutterImageView extends View implements RenderSurface {
     switch (kind) {
       case background:
         flutterRenderer.swapSurface(imageReader.getSurface());
+        flutterRenderer.SetRenderingToImageView(true);
         break;
       case overlay:
         // Do nothing since the attachment is done by the handler of
@@ -173,6 +174,12 @@ public class FlutterImageView extends View implements RenderSurface {
     closeCurrentImage();
     invalidate();
     isAttachedToFlutterRenderer = false;
+    if (kind == SurfaceKind.background) {
+      // The overlay FlutterImageViews seem to be constructed per frame and not
+      // always used; An overlay FlutterImageView always seems to imply
+      // a background FlutterImageView.
+      flutterRenderer.SetRenderingToImageView(false);
+    }
   }
 
   public void pause() {

engine/src/flutter/shell/platform/android/io/flutter/embedding/engine/FlutterJNI.java

@@ -740,6 +740,14 @@ public class FlutterJNI {
       int[] displayFeaturesBounds,
       int[] displayFeaturesType,
       int[] displayFeaturesState);
+
+  @UiThread
+  public void SetIsRenderingToImageView(boolean value) {
+    nativeSetIsRenderingToImageView(nativeShellHolderId, value);
+  }
+
+  private native void nativeSetIsRenderingToImageView(long nativeShellHolderId, boolean value);
+
   // ----- End Render Surface Support -----
 
   // ------ Start Touch Interaction Support ---

engine/src/flutter/shell/platform/android/io/flutter/embedding/engine/renderer/FlutterRenderer.java

@@ -50,6 +50,7 @@ public class FlutterRenderer implements TextureRegistry {
   @NonNull private final AtomicLong nextTextureId = new AtomicLong(0L);
   @Nullable private Surface surface;
   private boolean isDisplayingFlutterUi = false;
+  private int isRenderingToImageViewCount = 0;
   private Handler handler = new Handler();
 
   @NonNull
@@ -83,6 +84,19 @@ public class FlutterRenderer implements TextureRegistry {
     return isDisplayingFlutterUi;
   }
 
+  /**
+   * Informs the renderer whether the surface it is rendering to is backend by a {@code
+   * FlutterImageView}, which requires additional synchonization in the Vulkan backend.
+   */
+  public void SetRenderingToImageView(boolean value) {
+    if (value) {
+      isRenderingToImageViewCount++;
+    } else {
+      isRenderingToImageViewCount--;
+    }
+    flutterJNI.SetIsRenderingToImageView(isRenderingToImageViewCount > 0);
+  }
+
   /**
    * Adds a listener that is invoked whenever this {@code FlutterRenderer} starts and stops painting
    * pixels to an Android {@code View} hierarchy.

engine/src/flutter/shell/platform/android/platform_view_android.h

@@ -120,6 +120,12 @@ class PlatformViewAndroid final : public PlatformView {
     return platform_message_handler_;
   }
 
+  void SetIsRenderingToImageView(bool value) {
+    if (GetImpellerContext()) {
+      GetImpellerContext()->SetSyncPresentation(value);
+    }
+  }
+
  private:
   const std::shared_ptr<PlatformViewAndroidJNI> jni_facade_;
   std::shared_ptr<AndroidContext> android_context_;

engine/src/flutter/shell/platform/android/platform_view_android_jni_impl.cc

@@ -550,6 +550,13 @@ static void NotifyLowMemoryWarning(JNIEnv* env,
   ANDROID_SHELL_HOLDER->NotifyLowMemoryWarning();
 }
 
+static void SetIsRenderingToImageView(JNIEnv* env,
+                                      jobject jcaller,
+                                      jlong shell_holder,
+                                      bool value) {
+  ANDROID_SHELL_HOLDER->SetIsRenderingToImageView(value);
+}
+
 static jboolean FlutterTextUtilsIsEmoji(JNIEnv* env,
                                         jobject obj,
                                         jint codePoint) {
@@ -709,6 +716,11 @@ bool RegisterApi(JNIEnv* env) {
           .signature = "(J)V",
           .fnPtr = reinterpret_cast<void*>(&NotifyLowMemoryWarning),
       },
+      {
+          .name = "nativeSetIsRenderingToImageView",
+          .signature = "(JZ)V",
+          .fnPtr = reinterpret_cast<void*>(&SetIsRenderingToImageView),
+      },
 
       // Start of methods from FlutterView
       {