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Re: [Public WebGL] For review: ANGLE_timer_query extension






On Wed, Apr 3, 2013 at 2:36 PM, Florian Bösch <pyalot@gmail.com> wrote:
On Wed, Apr 3, 2013 at 11:31 PM, Gregg Tavares <gman@google.com> wrote:
The current proposal of caching results to prevent both spin waiting and inconsistent behavior would prevent you from figuring this stuff out in the same frame. Even if we didn't add those restrictions there's no guarantee the query will be available in time to use the info in the same frame.
In no way did I suggest that you would do it in the same frame. That would be silly. But if you measure by frames, then you can only find out about an impending issue post-hoc after you already dropped frames. Using timers you can find out about an impending issue before you drop frames by setting a budget target and undershoot.
 
Render them separately for the purpose of timing.
You cannot render part of the scene in one frame, and part in the next. You need a full frame to produce a picture. You can also not render one part and then call gl.finish(), that would block and degrades performance. That suggestion is invalid.

In no way did I suggest you would need a full frame to do this testing. If you want to know if a certain type of rendering is slow you can test your various types of rendering, off screen, at initialization time and find out which ones are slow.