[android] set presentation time via eglPresentationTimeANDROID

flow/surface_frame.h

@@ -11,6 +11,7 @@
 #include "flutter/common/graphics/gl_context_switch.h"
 #include "flutter/display_list/display_list_canvas_recorder.h"
 #include "flutter/fml/macros.h"
+#include "flutter/fml/time/time_point.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkSurface.h"
 
@@ -72,6 +73,10 @@ class SurfaceFrame {
     //
     // Corresponds to EGL_KHR_partial_update
     std::optional<SkIRect> buffer_damage;
+
+    // Time at which this frame is scheduled to be presented. This is a hint
+    // that can be passed to the platform to drop queued frames.
+    std::optional<fml::TimePoint> presentation_time;
   };
 
   bool Submit();

shell/common/rasterizer.cc

@@ -604,6 +604,14 @@ RasterStatus Rasterizer::DrawToSurfaceUnsafe(
     }
 
     SurfaceFrame::SubmitInfo submit_info;
+    // TODO (https://github.com/flutter/flutter/issues/105596): this can be in
+    // the past and might need to get snapped to future as this frame could have
+    // been resubmitted. `presentation_time` on `submit_info` is not set in this
+    // case.
+    const auto presentation_time = frame_timings_recorder.GetVsyncTargetTime();
+    if (presentation_time > fml::TimePoint::Now()) {
+      submit_info.presentation_time = presentation_time;
+    }
     if (damage) {
       submit_info.frame_damage = damage->GetFrameDamage();
       submit_info.buffer_damage = damage->GetBufferDamage();

shell/common/rasterizer_unittests.cc

@@ -7,6 +7,7 @@
 #include "flutter/shell/common/rasterizer.h"
 
 #include <memory>
+#include <optional>
 
 #include "flutter/flow/frame_timings.h"
 #include "flutter/fml/synchronization/count_down_latch.h"
@@ -777,7 +778,7 @@ TEST(RasterizerTest,
         framebuffer_info.supports_readback = true;
         return std::make_unique<SurfaceFrame>(
             /*surface=*/nullptr, framebuffer_info,
-            /*submit_callback=*/[](const SurfaceFrame&, SkCanvas*) {
+            /*submit_callback=*/[](const SurfaceFrame& frame, SkCanvas*) {
               return true;
             });
       }));
@@ -830,4 +831,152 @@ TEST(RasterizerTest,
   latch.Wait();
 }
 
+TEST(RasterizerTest, presentationTimeSetWhenVsyncTargetInFuture) {
+  std::string test_name =
+      ::testing::UnitTest::GetInstance()->current_test_info()->name();
+  ThreadHost thread_host("io.flutter.test." + test_name + ".",
+                         ThreadHost::Type::Platform | ThreadHost::Type::RASTER |
+                             ThreadHost::Type::IO | ThreadHost::Type::UI);
+  TaskRunners task_runners("test", thread_host.platform_thread->GetTaskRunner(),
+                           thread_host.raster_thread->GetTaskRunner(),
+                           thread_host.ui_thread->GetTaskRunner(),
+                           thread_host.io_thread->GetTaskRunner());
+  MockDelegate delegate;
+  ON_CALL(delegate, GetTaskRunners()).WillByDefault(ReturnRef(task_runners));
+
+  fml::AutoResetWaitableEvent latch;
+  std::unique_ptr<Rasterizer> rasterizer;
+  thread_host.raster_thread->GetTaskRunner()->PostTask([&] {
+    rasterizer = std::make_unique<Rasterizer>(delegate);
+    latch.Signal();
+  });
+  latch.Wait();
+
+  const auto millis_16 = fml::TimeDelta::FromMilliseconds(16);
+  const auto first_timestamp = fml::TimePoint::Now() + millis_16;
+  auto second_timestamp = first_timestamp + millis_16;
+  std::vector<fml::TimePoint> timestamps = {first_timestamp, second_timestamp};
+
+  int frames_submitted = 0;
+  fml::CountDownLatch submit_latch(2);
+  auto surface = std::make_unique<MockSurface>();
+  ON_CALL(*surface, AllowsDrawingWhenGpuDisabled()).WillByDefault(Return(true));
+  ON_CALL(*surface, AcquireFrame(SkISize()))
+      .WillByDefault(::testing::Invoke([&] {
+        SurfaceFrame::FramebufferInfo framebuffer_info;
+        framebuffer_info.supports_readback = true;
+        return std::make_unique<SurfaceFrame>(
+            /*surface=*/nullptr, framebuffer_info,
+            /*submit_callback=*/[&](const SurfaceFrame& frame, SkCanvas*) {
+              const auto pres_time = *frame.submit_info().presentation_time;
+              const auto diff = pres_time - first_timestamp;
+              int num_frames_submitted = frames_submitted++;
+              EXPECT_EQ(diff.ToMilliseconds(),
+                        num_frames_submitted * millis_16.ToMilliseconds());
+              submit_latch.CountDown();
+              return true;
+            });
+      }));
+
+  ON_CALL(*surface, MakeRenderContextCurrent())
+      .WillByDefault(::testing::Invoke(
+          [] { return std::make_unique<GLContextDefaultResult>(true); }));
+
+  thread_host.raster_thread->GetTaskRunner()->PostTask([&] {
+    rasterizer->Setup(std::move(surface));
+    auto pipeline = std::make_shared<LayerTreePipeline>(/*depth=*/10);
+    for (int i = 0; i < 2; i++) {
+      auto layer_tree =
+          std::make_unique<LayerTree>(/*frame_size=*/SkISize(),
+                                      /*device_pixel_ratio=*/2.0f);
+      auto layer_tree_item = std::make_unique<LayerTreeItem>(
+          std::move(layer_tree), CreateFinishedBuildRecorder(timestamps[i]));
+      PipelineProduceResult result =
+          pipeline->Produce().Complete(std::move(layer_tree_item));
+      EXPECT_TRUE(result.success);
+      EXPECT_EQ(result.is_first_item, i == 0);
+    }
+    auto no_discard = [](LayerTree&) { return false; };
+    // Although we only call 'Rasterizer::Draw' once, it will be called twice
+    // finally because there are two items in the pipeline.
+    rasterizer->Draw(pipeline, no_discard);
+  });
+
+  submit_latch.Wait();
+  thread_host.raster_thread->GetTaskRunner()->PostTask([&] {
+    rasterizer.reset();
+    latch.Signal();
+  });
+  latch.Wait();
+}
+
+TEST(RasterizerTest, presentationTimeNotSetWhenVsyncTargetInPast) {
+  std::string test_name =
+      ::testing::UnitTest::GetInstance()->current_test_info()->name();
+  ThreadHost thread_host("io.flutter.test." + test_name + ".",
+                         ThreadHost::Type::Platform | ThreadHost::Type::RASTER |
+                             ThreadHost::Type::IO | ThreadHost::Type::UI);
+  TaskRunners task_runners("test", thread_host.platform_thread->GetTaskRunner(),
+                           thread_host.raster_thread->GetTaskRunner(),
+                           thread_host.ui_thread->GetTaskRunner(),
+                           thread_host.io_thread->GetTaskRunner());
+  MockDelegate delegate;
+  ON_CALL(delegate, GetTaskRunners()).WillByDefault(ReturnRef(task_runners));
+
+  fml::AutoResetWaitableEvent latch;
+  std::unique_ptr<Rasterizer> rasterizer;
+  thread_host.raster_thread->GetTaskRunner()->PostTask([&] {
+    rasterizer = std::make_unique<Rasterizer>(delegate);
+    latch.Signal();
+  });
+  latch.Wait();
+
+  const auto millis_16 = fml::TimeDelta::FromMilliseconds(16);
+  const auto first_timestamp = fml::TimePoint::Now() - millis_16;
+
+  fml::CountDownLatch submit_latch(1);
+  auto surface = std::make_unique<MockSurface>();
+  ON_CALL(*surface, AllowsDrawingWhenGpuDisabled()).WillByDefault(Return(true));
+  ON_CALL(*surface, AcquireFrame(SkISize()))
+      .WillByDefault(::testing::Invoke([&] {
+        SurfaceFrame::FramebufferInfo framebuffer_info;
+        framebuffer_info.supports_readback = true;
+        return std::make_unique<SurfaceFrame>(
+            /*surface=*/nullptr, framebuffer_info,
+            /*submit_callback=*/[&](const SurfaceFrame& frame, SkCanvas*) {
+              const std::optional<fml::TimePoint> pres_time =
+                  frame.submit_info().presentation_time;
+              EXPECT_EQ(pres_time, std::nullopt);
+              submit_latch.CountDown();
+              return true;
+            });
+      }));
+
+  ON_CALL(*surface, MakeRenderContextCurrent())
+      .WillByDefault(::testing::Invoke(
+          [] { return std::make_unique<GLContextDefaultResult>(true); }));
+
+  thread_host.raster_thread->GetTaskRunner()->PostTask([&] {
+    rasterizer->Setup(std::move(surface));
+    auto pipeline = std::make_shared<LayerTreePipeline>(/*depth=*/10);
+    auto layer_tree = std::make_unique<LayerTree>(/*frame_size=*/SkISize(),
+                                                  /*device_pixel_ratio=*/2.0f);
+    auto layer_tree_item = std::make_unique<LayerTreeItem>(
+        std::move(layer_tree), CreateFinishedBuildRecorder(first_timestamp));
+    PipelineProduceResult result =
+        pipeline->Produce().Complete(std::move(layer_tree_item));
+    EXPECT_TRUE(result.success);
+    EXPECT_EQ(result.is_first_item, true);
+    auto no_discard = [](LayerTree&) { return false; };
+    rasterizer->Draw(pipeline, no_discard);
+  });
+
+  submit_latch.Wait();
+  thread_host.raster_thread->GetTaskRunner()->PostTask([&] {
+    rasterizer.reset();
+    latch.Signal();
+  });
+  latch.Wait();
+}
+
 }  // namespace flutter

shell/gpu/gpu_surface_gl_delegate.h

@@ -29,6 +29,10 @@ struct GLPresentInfo {
   // Damage is a hint to compositor telling it which parts of front buffer
   // need to be updated
   const std::optional<SkIRect>& damage;
+
+  // Time at which this frame is scheduled to be presented. This is a hint
+  // that can be passed to the platform to drop queued frames.
+  std::optional<fml::TimePoint> presentation_time = std::nullopt;
 };
 
 class GPUSurfaceGLDelegate {

shell/gpu/gpu_surface_gl_impeller.cc

@@ -63,6 +63,9 @@ std::unique_ptr<SurfaceFrame> GPUSurfaceGLImpeller::AcquireFrame(
       GLPresentInfo present_info = {
           .fbo_id = 0,
           .damage = std::nullopt,
+          // TODO (https://github.com/flutter/flutter/issues/105597): wire-up
+          // presentation time to impeller backend.
+          .presentation_time = std::nullopt,
       };
       delegate->GLContextPresent(present_info);
     }

shell/gpu/gpu_surface_gl_skia.cc

@@ -266,7 +266,11 @@ bool GPUSurfaceGLSkia::PresentSurface(const SurfaceFrame& frame,
     onscreen_surface_->getCanvas()->flush();
   }
 
-  GLPresentInfo present_info = {fbo_id_, frame.submit_info().frame_damage};
+  GLPresentInfo present_info = {
+      .fbo_id = fbo_id_,
+      .damage = frame.submit_info().frame_damage,
+      .presentation_time = frame.submit_info().presentation_time,
+  };
   if (!delegate_->GLContextPresent(present_info)) {
     return false;
   }

shell/platform/android/android_egl_surface.cc

@@ -60,6 +60,17 @@ void LogLastEGLError() {
   FML_LOG(ERROR) << "Unknown EGL Error";
 }
 
+namespace {
+
+static bool HasExtension(const char* extensions, const char* name) {
+  const char* r = strstr(extensions, name);
+  auto len = strlen(name);
+  // check that the extension name is terminated by space or null terminator
+  return r != nullptr && (r[len] == ' ' || r[len] == 0);
+}
+
+}  // namespace
+
 class AndroidEGLSurfaceDamage {
  public:
   void init(EGLDisplay display, EGLContext context) {
@@ -170,13 +181,6 @@ class AndroidEGLSurfaceDamage {
 
   bool partial_redraw_supported_;
 
-  bool HasExtension(const char* extensions, const char* name) {
-    const char* r = strstr(extensions, name);
-    auto len = strlen(name);
-    // check that the extension name is terminated by space or null terminator
-    return r != nullptr && (r[len] == ' ' || r[len] == 0);
-  }
-
   std::list<SkIRect> damage_history_;
 };
 
@@ -188,6 +192,14 @@ AndroidEGLSurface::AndroidEGLSurface(EGLSurface surface,
       context_(context),
       damage_(std::make_unique<AndroidEGLSurfaceDamage>()) {
   damage_->init(display_, context);
+
+  const char* extensions = eglQueryString(display, EGL_EXTENSIONS);
+
+  if (HasExtension(extensions, "EGL_ANDROID_presentation_time")) {
+    presentation_time_proc_ =
+        reinterpret_cast<PFNEGLPRESENTATIONTIMEANDROIDPROC>(
+            eglGetProcAddress("eglPresentationTimeANDROID"));
+  }
 }
 
 AndroidEGLSurface::~AndroidEGLSurface() {
@@ -240,6 +252,16 @@ void AndroidEGLSurface::SetDamageRegion(
   damage_->SetDamageRegion(display_, surface_, buffer_damage);
 }
 
+bool AndroidEGLSurface::SetPresentationTime(
+    const fml::TimePoint& presentation_time) {
+  if (presentation_time_proc_) {
+    const auto time_ns = presentation_time.ToEpochDelta().ToNanoseconds();
+    return presentation_time_proc_(display_, surface_, time_ns);
+  } else {
+    return false;
+  }
+}
+
 bool AndroidEGLSurface::SwapBuffers(
     const std::optional<SkIRect>& surface_damage) {
   TRACE_EVENT0("flutter", "AndroidContextGL::SwapBuffers");

shell/platform/android/android_egl_surface.h

@@ -5,9 +5,13 @@
 #ifndef FLUTTER_SHELL_PLATFORM_ANDROID_ANDROID_EGL_SURFACE_H_
 #define FLUTTER_SHELL_PLATFORM_ANDROID_ANDROID_EGL_SURFACE_H_
 
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+#include <KHR/khrplatform.h>
 #include <optional>
 
 #include "flutter/fml/macros.h"
+#include "flutter/fml/time/time_point.h"
 #include "flutter/shell/platform/android/android_environment_gl.h"
 #include "third_party/skia/include/core/SkRect.h"
 
@@ -77,6 +81,12 @@ class AndroidEGLSurface {
   //              eglSetDamageRegionKHR
   void SetDamageRegion(const std::optional<SkIRect>& buffer_damage);
 
+  //----------------------------------------------------------------------------
+  /// @brief      Sets the presentation time for the current surface. This
+  //              corresponds to calling eglPresentationTimeAndroid when
+  //              available.
+  bool SetPresentationTime(const fml::TimePoint& presentation_time);
+
   //----------------------------------------------------------------------------
   /// @brief      This only applies to on-screen surfaces such as those created
   ///             by `AndroidContextGL::CreateOnscreenSurface`.
@@ -98,6 +108,7 @@ class AndroidEGLSurface {
   const EGLDisplay display_;
   const EGLContext context_;
   std::unique_ptr<AndroidEGLSurfaceDamage> damage_;
+  PFNEGLPRESENTATIONTIMEANDROIDPROC presentation_time_proc_;
 };
 
 }  // namespace flutter

shell/platform/android/android_surface_gl_skia.cc

@@ -156,6 +156,9 @@ void AndroidSurfaceGLSkia::GLContextSetDamageRegion(
 bool AndroidSurfaceGLSkia::GLContextPresent(const GLPresentInfo& present_info) {
   FML_DCHECK(IsValid());
   FML_DCHECK(onscreen_surface_);
+  if (present_info.presentation_time) {
+    onscreen_surface_->SetPresentationTime(*present_info.presentation_time);
+  }
   return onscreen_surface_->SwapBuffers(present_info.damage);
 }