Clamp YUV videos to their visible size in the shader

cc/output/renderer_pixeltest.cc

Index: cc/output/renderer_pixeltest.cc
diff --git a/cc/output/renderer_pixeltest.cc b/cc/output/renderer_pixeltest.cc
index 08a40530eb4753c1257a963e72bcc15c5a2f0af3..b8e0240f9631ef89cf9ec8cf1ea0b4371818be9f 100644
--- a/cc/output/renderer_pixeltest.cc
+++ b/cc/output/renderer_pixeltest.cc
@@ -460,6 +460,62 @@ class VideoGLRendererPixelTest : public GLRendererPixelTest {
         shared_state, video_frame, is_transparent, tex_coord_rect, render_pass);
   }
 
+  void CreateTestYUVVideoDrawQuad_TwoColor(const SharedQuadState* shared_state,

[danakj, 2015/02/02 18:43:03]

can you leave a comment in here somewhere that explains what this function
creates in a bit more detail?

+                                           media::VideoFrame::Format format,
+                                           bool is_transparent,
+                                           const gfx::RectF& tex_coord_rect,
+                                           const gfx::Size& background_size,
+                                           uint8 y_background,
+                                           uint8 u_background,
+                                           uint8 v_background,
+                                           const gfx::Rect& foreground_rect,
+                                           uint8 y_foreground,
+                                           uint8 u_foreground,
+                                           uint8 v_foreground,
+                                           RenderPass* render_pass) {
+    const gfx::Rect rect(background_size);
+
+    scoped_refptr<media::VideoFrame> video_frame =
+        media::VideoFrame::CreateFrame(format, background_size, foreground_rect,
+                                       foreground_rect.size(),
+                                       base::TimeDelta());
+
+    int planes[] = {media::VideoFrame::kYPlane,
+                    media::VideoFrame::kUPlane,
+                    media::VideoFrame::kVPlane};
+    uint8 yuv_background[] = {y_background, u_background, v_background};
+    uint8 yuv_foreground[] = {y_foreground, u_foreground, v_foreground};
+    int sample_size[] = {1, 2, 2};
+
+    for (int i = 0; i < 3; ++i) {
+      memset(video_frame->data(planes[i]), yuv_background[i],
+             video_frame->stride(planes[i]) * video_frame->rows(planes[i]));
+    }
+
+    for (int i = 0; i < 3; ++i) {
+      // Since yuv encoding uses block encoding, widths have to be divisible
+      // by the sample size in order for this function to behave properly.
+      DCHECK_EQ(foreground_rect.x() % sample_size[i], 0);
+      DCHECK_EQ(foreground_rect.y() % sample_size[i], 0);
+      DCHECK_EQ(foreground_rect.width() % sample_size[i], 0);
+      DCHECK_EQ(foreground_rect.height() % sample_size[i], 0);
+
+      gfx::Rect sample_rect(foreground_rect.x() / sample_size[i],
+                            foreground_rect.y() / sample_size[i],
+                            foreground_rect.width() / sample_size[i],
+                            foreground_rect.height() / sample_size[i]);
+      for (int y = sample_rect.y(); y < sample_rect.bottom(); ++y) {
+        for (int x = sample_rect.x(); x < sample_rect.right(); ++x) {
+          size_t offset = y * video_frame->stride(planes[i]) + x;
+          video_frame->data(planes[i])[offset] = yuv_foreground[i];
+        }
+      }
+    }
+
+    CreateTestYUVVideoDrawQuad_FromVideoFrame(
+        shared_state, video_frame, is_transparent, tex_coord_rect, render_pass);
+  }
+
   void CreateTestYUVVideoDrawQuad_FromVideoFrame(
       const SharedQuadState* shared_state,
       scoped_refptr<media::VideoFrame> video_frame,
@@ -471,7 +527,7 @@ class VideoGLRendererPixelTest : public GLRendererPixelTest {
         (video_frame->format() == media::VideoFrame::YV12J
              ? YUVVideoDrawQuad::REC_601_JPEG
              : YUVVideoDrawQuad::REC_601);
-    const gfx::Rect rect(this->device_viewport_size_);
+    const gfx::Rect rect(shared_state->content_bounds);

[enne (OOO), 2015/01/31 01:32:14]

Without this change, the video quads were ending up being the entire viewport
size (and then scaled).  Oops.

     const gfx::Rect opaque_rect(0, 0, 0, 0);
 
     if (with_alpha)
@@ -515,16 +571,9 @@ class VideoGLRendererPixelTest : public GLRendererPixelTest {
 
     YUVVideoDrawQuad* yuv_quad =
         render_pass->CreateAndAppendDrawQuad<YUVVideoDrawQuad>();
-    yuv_quad->SetNew(shared_state,
-                     rect,
-                     opaque_rect,
-                     rect,
-                     tex_coord_rect,
-                     y_resource,
-                     u_resource,
-                     v_resource,
-                     a_resource,
-                     color_space);
+    yuv_quad->SetNew(shared_state, rect, opaque_rect, rect, tex_coord_rect,
+                     video_frame->coded_size(), y_resource, u_resource,
+                     v_resource, a_resource, color_space);
   }
 
   void SetUp() override {
@@ -642,6 +691,47 @@ TEST_F(VideoGLRendererPixelTest, SimpleYUVJRect) {
                                  FuzzyPixelOffByOneComparator(true)));
 }
 
+// Test that a YUV video doesn't bleed outside of its tex coords when the

[danakj, 2015/02/02 18:43:03]

Should we test YUVA shader too?

+// tex coord rect is only a partial subrectangle of the coded contents.
+TEST_F(VideoGLRendererPixelTest, YUVEdgeBleed) {
+  gfx::Rect rect(200, 200);
+
+  RenderPassId id(1, 1);
+  scoped_ptr<RenderPass> pass = CreateTestRootRenderPass(id, rect);
+
+  // Scale the video up so that bilinear filtering kicks in to sample more
+  // than just nearest neighbor would.
+  gfx::Transform scale_by_2;
+  scale_by_2.Scale(2.f, 2.f);
+  gfx::Rect half_rect(100, 100);
+  SharedQuadState* shared_state =
+      CreateTestSharedQuadState(scale_by_2, half_rect, pass.get());
+
+  gfx::Size background_size(200, 200);
+  gfx::Rect green_rect(16, 20, 100, 100);
+  gfx::RectF tex_coord_rect(
+      static_cast<float>(green_rect.x()) / background_size.width(),
+      static_cast<float>(green_rect.y()) / background_size.height(),
+      static_cast<float>(green_rect.width()) / background_size.width(),
+      static_cast<float>(green_rect.height()) / background_size.height());
+
+  // YUV of (149,43,21) should be green (0,255,0) in RGB.
+  // Create a video frame that has a non-green background rect, with a
+  // green sub-rectangle that should be the only thing displayed in
+  // the final image.  Bleeding will appear on all four sides of the video
+  // if the tex coords are not clamped.
+  CreateTestYUVVideoDrawQuad_TwoColor(
+      shared_state, media::VideoFrame::YV12J, false, tex_coord_rect,
+      background_size, 0, 0, 0, green_rect, 149, 43, 21, pass.get());
+
+  RenderPassList pass_list;
+  pass_list.push_back(pass.Pass());
+
+  EXPECT_TRUE(this->RunPixelTest(&pass_list,
+                                 base::FilePath(FILE_PATH_LITERAL("green.png")),
+                                 FuzzyPixelOffByOneComparator(true)));
+}
+
 TEST_F(VideoGLRendererPixelTest, SimpleYUVJRectGrey) {
   gfx::Rect rect(this->device_viewport_size_);