ReadPixels from known-usable textures, and give SkBitmap its precious BGRA.

content/renderer/media/renderer_gpu_video_decoder_factories.cc

 // Copyright (c) 2012 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/renderer_gpu_video_decoder_factories.h"
 
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 
 #include "base/bind.h"
@@ skipping 157 matching lines @@
 
 void RendererGpuVideoDecoderFactories::AsyncReadPixels(
     uint32 texture_id, uint32 texture_target, const gfx::Size& size,
     void* pixels, base::WaitableEvent* waiter) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   if (!context_)
     return;
 
   gpu::gles2::GLES2Implementation* gles2 = context_->GetImplementation();
 
-  gles2->ActiveTexture(GL_TEXTURE0);
-  gles2->BindTexture(texture_target, texture_id);
-  gles2->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-  gles2->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-  gles2->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-  gles2->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  GLuint tmp_texture;
+  gles2->GenTextures(1, &tmp_texture);
+  gles2->BindTexture(texture_target, tmp_texture);
+  gles2->TexParameteri(texture_target, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  gles2->TexParameteri(texture_target, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+  gles2->TexParameteri(texture_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  gles2->TexParameteri(texture_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  context_->copyTextureCHROMIUM(
+      texture_target, texture_id, tmp_texture, 0, GL_RGBA);
 
   GLuint fb;
   gles2->GenFramebuffers(1, &fb);
   gles2->BindFramebuffer(GL_FRAMEBUFFER, fb);
   gles2->FramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
-                              texture_target, texture_id, 0);
+                              texture_target, tmp_texture, 0);
   gles2->PixelStorei(GL_PACK_ALIGNMENT, 4);
+#if defined(OS_WIN)
+  // DXVA on Windows replaces our precious RGBA with BGRA.  Undo that here.
+  gles2->ReadPixels(0, 0, size.width(), size.height(), GL_BGRA_EXT,
+                    GL_UNSIGNED_BYTE, pixels);

[piman, 2012/10/02 19:38:50]

Shouldn't that be fixed in the GPU process? It looks wrong - if you ask one
format you shouldn't get pixels in the other format.

[Ami GONE FROM CHROMIUM, 2012/10/02 19:49:23]

Agreed with the "should" there, but not sure how.

DXVA fails to create textures if I ask for RGBA instead of BGRA (and, helpfully
enough, D3D_FORMAT reverses the pixel order for its constant naming...).

I can't change the GL_RGBA in CreateTextures to GL_BGRA_EXT b/c other decoders
really do do RGBA.  

Suggestions?

+#else
   gles2->ReadPixels(0, 0, size.width(), size.height(), GL_RGBA,
                     GL_UNSIGNED_BYTE, pixels);
+#endif
   gles2->DeleteFramebuffers(1, &fb);
+  gles2->DeleteTextures(1, &tmp_texture);
   DCHECK_EQ(gles2->GetError(), static_cast<GLenum>(GL_NO_ERROR));
   waiter->Signal();
 }
 
 base::SharedMemory* RendererGpuVideoDecoderFactories::CreateSharedMemory(
     size_t size) {
   DCHECK_NE(MessageLoop::current(), ChildThread::current()->message_loop());
   base::SharedMemory* shm = NULL;
   base::WaitableEvent waiter(false, false);
   ChildThread::current()->message_loop()->PostTask(FROM_HERE, base::Bind(
       &RendererGpuVideoDecoderFactories::AsyncCreateSharedMemory, this,
       size, &shm, &waiter));
   waiter.Wait();
   return shm;
 }
 
 void RendererGpuVideoDecoderFactories::AsyncCreateSharedMemory(
     size_t size, base::SharedMemory** shm, base::WaitableEvent* waiter) {
   DCHECK_EQ(MessageLoop::current(), ChildThread::current()->message_loop());
   *shm = ChildThread::current()->AllocateSharedMemory(size);
   waiter->Signal();
 }