gpu: Defer reads from default framebuffer when needed.

gpu: Defer reads from default framebuffer when needed.

On some platforms, we want to unschedule after a swap until the ack, but the
DeferDraws mechanism allows us to delay the unschedule until we actually need to
access the back buffer. Up to now, only commands that *write* to the framebuffer
were considered, however we also need to consider *reads*. This fixes that.

BUG=None


Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=170435

[piman, 2012-11-30 01:52:12]

https://codereview.chromium.org/11412262/diff/1/gpu/command_buffer/service/gl...
File gpu/command_buffer/service/gles2_cmd_decoder.cc (right):

https://codereview.chromium.org/11412262/diff/1/gpu/command_buffer/service/gl...
gpu/command_buffer/service/gles2_cmd_decoder.cc:3105: if
(!offscreen_target_frame_buffer_.get() && surface_->DeferDraws())
Note here: ResizeCHROMIUM resizes the default FBO regardless of what is bound,
hence this change.

[greggman, 2012-11-30 02:49:01]

https://codereview.chromium.org/11412262/diff/1/gpu/command_buffer/build_gles...
File gpu/command_buffer/build_gles2_cmd_buffer.py (right):

https://codereview.chromium.org/11412262/diff/1/gpu/command_buffer/build_gles...
gpu/command_buffer/build_gles2_cmd_buffer.py:1186: 'pepper_interface':
'FramebufferBlit',
Would be better to add add a couple of flags here?

'defer_draw': True,
'defer_read': True,

And adjust the generation code?

[piman, 2012-11-30 04:52:34]

https://codereview.chromium.org/11412262/diff/1/gpu/command_buffer/build_gles...
File gpu/command_buffer/build_gles2_cmd_buffer.py (right):

https://codereview.chromium.org/11412262/diff/1/gpu/command_buffer/build_gles...
gpu/command_buffer/build_gles2_cmd_buffer.py:1186: 'pepper_interface':
'FramebufferBlit',
On 2012/11/30 02:49:01, greggman wrote:
> Would be better to add add a couple of flags here?
> 
> 'defer_draw': True,
> 'defer_read': True,
> 
> And adjust the generation code?

Done.

[greggman, 2012-11-30 05:15:16]

lgtm

[commit-bot: I haz the power, 2012-11-30 08:22:48]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/piman@chromium.org/11412262/8001

[commit-bot: I haz the power, 2012-11-30 10:30:45]

Change committed as 170435