Add external surface rendering mode

cc/gl_renderer.cc

Index: cc/gl_renderer.cc
diff --git a/cc/gl_renderer.cc b/cc/gl_renderer.cc
index a40dd3a245b80e384bea0d7cce273d2d441ff6ba..1c01675035e33bc7a7ac6b0d6d288b40c2697a7b 100644
--- a/cc/gl_renderer.cc
+++ b/cc/gl_renderer.cc
@@ -936,15 +936,22 @@ void GLRenderer::drawStreamVideoQuad(const DrawingFrame& frame, const StreamVide
     const VideoStreamTextureProgram* program = videoStreamTextureProgram();
     setUseProgram(program->program());
 
-    toGLMatrix(&glMatrix[0], quad->matrix);
-    GLC(context(), context()->uniformMatrix4fv(program->vertexShader().texMatrixLocation(), 1, false, glMatrix));
+    if (quad->texture_id == 0) {
+        // When texture_id == 0, punch a hole instead of rendering.
+        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));
+    } else {

[danakj, 2012/12/13 05:35:42]

if you return at the end of the if() then you don't need the else{}.

[wonsik2, 2012/12/17 04:36:05]

Done.

+        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()->bindTexture(GL_TEXTURE_EXTERNAL_OES, quad->texture_id));
 
-    GLC(context(), context()->uniform1i(program->fragmentShader().samplerLocation(), 0));
+        GLC(context(), context()->uniform1i(program->fragmentShader().samplerLocation(), 0));
 
-    setShaderOpacity(quad->opacity(), program->fragmentShader().alphaLocation());
-    drawQuadGeometry(frame, quad->quadTransform(), quad->rect, program->vertexShader().matrixLocation());
+        setShaderOpacity(quad->opacity(), program->fragmentShader().alphaLocation());
+        drawQuadGeometry(frame, quad->quadTransform(), quad->rect, program->vertexShader().matrixLocation());
+    }
 }
 
 struct TextureProgramBinding {