Add a new API to create a surfaceless GLSurface for Ozone

content/common/gpu/media/rendering_helper.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/common/gpu/media/rendering_helper.h"
 
 #include <algorithm>
 #include <numeric>
 #include <vector>
 
@@ skipping 348 matching lines @@
     glFramebufferTexture2DEXT(GL_FRAMEBUFFER,
                               GL_COLOR_ATTACHMENT0,
                               GL_TEXTURE_2D,
                               thumbnails_texture_id_,
                               0);
 
     GLenum fb_status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER);
     CHECK(fb_status == GL_FRAMEBUFFER_COMPLETE) << fb_status;
     glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
     glClear(GL_COLOR_BUFFER_BIT);
-    glBindFramebufferEXT(GL_FRAMEBUFFER, 0);
+    glBindFramebufferEXT(GL_FRAMEBUFFER,
+                         gl_surface_->GetBackingFrameBufferObject());
   }
 
   // These vertices and texture coords. map (0,0) in the texture to the
   // bottom left of the viewport.  Since we get the video frames with the
   // the top left at (0,0) we need to flip the texture y coordinate
   // in the vertex shader for this to be rendered the right way up.
   // In the case of thumbnail rendering we use the same vertex shader
   // to render the FBO the screen, where we do not want this flipping.
   static const float kVertices[] =
       { -1.f, 1.f, -1.f, -1.f, 1.f, 1.f, 1.f, -1.f, };
@@ skipping 185 matching lines @@
   const int thumbnails_in_column = thumbnails_fbo_size_.height() / height;
   const int row = (frame_count_ / thumbnails_in_row) % thumbnails_in_column;
   const int col = frame_count_ % thumbnails_in_row;
 
   gfx::Rect area(col * width, row * height, width, height);
 
   glUniform1i(glGetUniformLocation(program_, "tex_flip"), 0);
   glBindFramebufferEXT(GL_FRAMEBUFFER, thumbnails_fbo_id_);
   GLSetViewPort(area);
   RenderTexture(texture_target, texture_id);
-  glBindFramebufferEXT(GL_FRAMEBUFFER, 0);
+  glBindFramebufferEXT(GL_FRAMEBUFFER,
+                       gl_surface_->GetBackingFrameBufferObject());
 
   // Need to flush the GL commands before we return the tnumbnail texture to
   // the decoder.
   glFlush();
   ++frame_count_;
 }
 
 void RenderingHelper::QueueVideoFrame(
     size_t window_id,
     scoped_refptr<VideoFrameTexture> video_frame) {
@@ skipping 70 matching lines @@
   glBindFramebufferEXT(GL_FRAMEBUFFER, thumbnails_fbo_id_);
   glPixelStorei(GL_PACK_ALIGNMENT, 1);
   // We can only count on GL_RGBA/GL_UNSIGNED_BYTE support.
   glReadPixels(0,
                0,
                thumbnails_fbo_size_.width(),
                thumbnails_fbo_size_.height(),
                GL_RGBA,
                GL_UNSIGNED_BYTE,
                &rgba[0]);
-  glBindFramebufferEXT(GL_FRAMEBUFFER, 0);
+  glBindFramebufferEXT(GL_FRAMEBUFFER,
+                       gl_surface_->GetBackingFrameBufferObject());
   rgb->resize(num_pixels * 3);
   // Drop the alpha channel, but check as we go that it is all 0xff.
   bool solid = true;
   unsigned char* rgb_ptr = &((*rgb)[0]);
   unsigned char* rgba_ptr = &rgba[0];
   for (size_t i = 0; i < num_pixels; ++i) {
     *rgb_ptr++ = *rgba_ptr++;
     *rgb_ptr++ = *rgba_ptr++;
     *rgb_ptr++ = *rgba_ptr++;
     solid = solid && (*rgba_ptr == 0xff);
@@ skipping 16 matching lines @@
   // It's safe to use Unretained here since |rendering_thread_| will be stopped
   // in VideoDecodeAcceleratorTest.TearDown(), while the |rendering_helper_| is
   // a member of that class. (See video_decode_accelerator_unittest.cc.)
   gfx::VSyncProvider* vsync_provider = gl_surface_->GetVSyncProvider();
   if (vsync_provider) {
     vsync_provider->GetVSyncParameters(base::Bind(
         &RenderingHelper::UpdateVSyncParameters, base::Unretained(this),
         static_cast<base::WaitableEvent*>(NULL)));
   }
 
-  glUniform1i(glGetUniformLocation(program_, "tex_flip"), 1);
+  int tex_flip = 1;
+#if USE_OZONE
+  // Ozone surfaceless renders flipped from normal GL, so there's no need to
+  // do an extra flip.
+  tex_flip = 0;

[spang, 2015/02/19 00:49:26]

What if it's not surfaceless?

[achaulk, 2015/02/19 00:54:50]

Hmm, I could add a property to GLSurface to indicate if it is flipped or not,
but otherwise we won't know

+#endif
+  glUniform1i(glGetUniformLocation(program_, "tex_flip"), tex_flip);
 
   // Frames that will be returned to the client (via the no_longer_needed_cb)
   // after this vector falls out of scope at the end of this method. We need
   // to keep references to them until after SwapBuffers() call below.
   std::vector<scoped_refptr<VideoFrameTexture> > frames_to_be_returned;
   bool need_swap_buffer = false;
   if (render_as_thumbnails_) {
     // In render_as_thumbnails_ mode, we render the FBO content on the
     // screen instead of the decoded textures.
     GLSetViewPort(videos_[0].render_area);
@@ skipping 119 matching lines @@
   // When the rendering falls behind, drops frames.
   while (scheduled_render_time_ < target) {
     scheduled_render_time_ += frame_duration_;
     DropOneFrameForAllVideos();
   }
 
   message_loop_->PostDelayedTask(
       FROM_HERE, render_task_.callback(), target - now);
 }
 }  // namespace content