webgl: optimize webgl.texSubImage2D(video) path.

content/renderer/media/android/webmediaplayer_android.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/android/webmediaplayer_android.h"
 
 #include <limits>
 
 #include "base/android/build_info.h"
 #include "base/bind.h"
@@ skipping 619 matching lines @@
   // a new one based on video size.
   if (!IsSkBitmapProperlySizedTexture(&bitmap_, naturalSize())) {
     if (!AllocateSkBitmapTexture(provider->grContext(), &bitmap_,
                                  naturalSize())) {
       return;
     }
   }
 
   unsigned textureId = static_cast<unsigned>(
     (bitmap_.getTexture())->getTextureHandle());
-  if (!copyVideoTextureToPlatformTexture(context3D, textureId,
-      GL_RGBA, GL_UNSIGNED_BYTE, true, false)) {
+  if (!copyVideoTextureToPlatformTexture(context3D, GL_TEXTURE_2D, textureId,
+                                         GL_RGBA, GL_UNSIGNED_BYTE, 0, true,
+                                         false)) {
     return;
   }
 
   // Draw the texture based bitmap onto the Canvas. If the canvas is
   // hardware based, this will do a GPU-GPU texture copy.
   // If the canvas is software based, the texture based bitmap will be
   // readbacked to system memory then draw onto the canvas.
   SkRect dest;
   dest.set(rect.x, rect.y, rect.x + rect.width, rect.y + rect.height);
   SkPaint paint;
   paint.setAlpha(alpha);
   paint.setXfermodeMode(mode);
   // It is not necessary to pass the dest into the drawBitmap call since all
   // the context have been set up before calling paintCurrentFrameInContext.
   canvas->drawBitmapRect(bitmap_, dest, &paint);
 }
 
 bool WebMediaPlayerAndroid::copyVideoTextureToPlatformTexture(
     blink::WebGraphicsContext3D* web_graphics_context,
     unsigned int texture,
     unsigned int internal_format,
     unsigned int type,
     bool premultiply_alpha,
     bool flip_y) {
+  return copyVideoTextureToPlatformTexture(web_graphics_context, GL_TEXTURE_2D,
+                                           texture, internal_format, type, 0,
+                                           premultiply_alpha, flip_y);
+}
+
+bool WebMediaPlayerAndroid::copyVideoTextureToPlatformTexture(
+    blink::WebGraphicsContext3D* web_graphics_context,
+    unsigned int target,
+    unsigned int texture,
+    unsigned int internal_format,
+    unsigned int type,
+    int level,
+    bool premultiply_alpha,
+    bool flip_y) {
+  return CopyVideoTextureToPlatformTextureInternal(
+      web_graphics_context, true, target, texture, internal_format, type, level,
+      0, 0, premultiply_alpha, flip_y);
+}
+
+bool WebMediaPlayerAndroid::copyVideoSubTextureToPlatformTexture(
+    blink::WebGraphicsContext3D* web_graphics_context,
+    unsigned int target,
+    unsigned int texture,
+    int level,
+    int xoffset,
+    int yoffset,
+    bool premultiply_alpha,
+    bool flip_y) {
+  return CopyVideoTextureToPlatformTextureInternal(
+      web_graphics_context, false, target, texture, GL_FALSE, GL_FALSE, level,
+      xoffset, yoffset, premultiply_alpha, flip_y);
+}
+
+bool WebMediaPlayerAndroid::CopyVideoTextureToPlatformTextureInternal(
+    blink::WebGraphicsContext3D* web_graphics_context,
+    bool is_full_copy,
+    unsigned int target,
+    unsigned int texture,
+    unsigned int internal_format,
+    unsigned int type,
+    int level,
+    int xoffset,
+    int yoffset,
+    bool premultiply_alpha,
+    bool flip_y) {
   DCHECK(main_thread_checker_.CalledOnValidThread());
   // Don't allow clients to copy an encrypted video frame.
   if (needs_external_surface_)
     return false;
 
   scoped_refptr<VideoFrame> video_frame;
   {
     base::AutoLock auto_lock(current_frame_lock_);
     video_frame = current_frame_;
   }
@@ skipping 11 matching lines @@
   // Ensure the target of texture is set before copyTextureCHROMIUM, otherwise
   // an invalid texture target may be used for copy texture.
   uint32 src_texture =
       web_graphics_context->createAndConsumeTextureCHROMIUM(
           mailbox_holder.texture_target, mailbox_holder.mailbox.name);
 
   // Application itself needs to take care of setting the right flip_y
   // value down to get the expected result.
   // flip_y==true means to reverse the video orientation while
   // flip_y==false means to keep the intrinsic orientation.
-  web_graphics_context->copyTextureCHROMIUM(
-      GL_TEXTURE_2D, src_texture, texture, internal_format, type,
-      flip_y, premultiply_alpha, false);
+  if (is_full_copy) {

[piman, 2015/09/04 17:34:29]

nit: maybe DCHECK that xoffset/yoffset are 0 here?

+    web_graphics_context->copyTextureCHROMIUM(target, src_texture, texture,
+                                              internal_format, type, flip_y,
+                                              premultiply_alpha, false);
+  } else {
+    web_graphics_context->copySubTextureCHROMIUM(
+        target, src_texture, texture, xoffset, yoffset, 0, 0,
+        video_frame->natural_size().width(),
+        video_frame->natural_size().height(), flip_y, premultiply_alpha, false);
+  }
 
   web_graphics_context->deleteTexture(src_texture);
   web_graphics_context->flush();
 
   SyncPointClientImpl client(web_graphics_context);
   video_frame->UpdateReleaseSyncPoint(&client);
   return true;
 }
 
 bool WebMediaPlayerAndroid::hasSingleSecurityOrigin() const {
@@ skipping 1197 matching lines @@
 
   bool is_hls = IsHLSStream();
   UMA_HISTOGRAM_BOOLEAN("Media.Android.IsHttpLiveStreamingMedia", is_hls);
   if (is_hls) {
     media::RecordOriginOfHLSPlayback(
         GURL(frame_->document().securityOrigin().toString()));
   }
 }
 
 }  // namespace content