Add external surface rendering mode

cc/gl_renderer.cc

 // Copyright 2010 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 "cc/gl_renderer.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/string_split.h"
 #include "base/string_util.h"
@@ skipping 918 matching lines @@
 
 void GLRenderer::drawStreamVideoQuad(const DrawingFrame& frame, const StreamVideoDrawQuad* quad)
 {
     static float glMatrix[16];
 
     DCHECK(m_capabilities.usingEglImage);
 
     const VideoStreamTextureProgram* program = videoStreamTextureProgram();
     setUseProgram(program->program());
 
+    if (quad->texture_id == 0) {
+        // When texture_id == 0, punch a hole instead of rendering.

[qinmin, 2012/12/17 19:34:06]

nit: fix indent

[enne (OOO), 2012/12/17 20:38:28]

What do you mean by punch a hole? Maybe I'm misunderstanding this CL, but I'm
not sure why you'd even generate a quad for this video; it sounded from the
description like you were going to composite this video external to cc.

[wonsik2, 2013/02/14 14:56:38]

It seems that 4 spaces are used throughout the file. Please follow up at
https://codereview.chromium.org/12255032/

[wonsik2, 2013/02/14 14:56:38]

Skipping a quad will make the background occlude the video composited outside of
cc. I added more comments: please follow up at
https://codereview.chromium.org/12255032/

+        GLC(m_context, m_context->blendFunc(GL_ZERO, GL_ONE_MINUS_SRC_ALPHA));
+        drawQuadGeometry(frame, quad->quadTransform(), quad->rect, program->vertexShader().matrixLocation());
+        GLC(m_context, m_context->blendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA));
+        return;
+    }
     toGLMatrix(&glMatrix[0], quad->matrix);
     GLC(context(), context()->uniformMatrix4fv(program->vertexShader().texMatrixLocation(), 1, false, glMatrix));
 
     GLC(context(), context()->bindTexture(GL_TEXTURE_EXTERNAL_OES, quad->texture_id));
 
     GLC(context(), context()->uniform1i(program->fragmentShader().samplerLocation(), 0));
 
     setShaderOpacity(quad->opacity(), program->fragmentShader().alphaLocation());
     drawQuadGeometry(frame, quad->quadTransform(), quad->rect, program->vertexShader().matrixLocation());
 }
@@ skipping 797 matching lines @@
 
     releaseRenderPassTextures();
 }
 
 bool GLRenderer::isContextLost()
 {
     return (m_context->getGraphicsResetStatusARB() != GL_NO_ERROR);
 }
 
 }  // namespace cc