[Development] Scenegraph Triple Buffering

gunnar.sletta at nokia.com gunnar.sletta at nokia.com
Thu Jun 28 11:38:08 CEST 2012


On Jun 28, 2012, at 10:58 AM, ext Dietrich.Gossen at conti-engineering.com wrote:

> Hi, 
> 
> There is some Qt 5.0 documentation available about QSurfaceFormat::SwapBehavior. There is a constant called QSurfaceFormat::TripleBuffer . 
> Is this feature already implemented and tested in Qt 5 Alpha? 

This parameter is picked up by the platform's OpenGL implementation if anything, but none of our desktop backends currently make use of this as the buffering policy is typically decided for us by the system. This is mostly a hint to be picked up by EGL implementations where applicable.

> The reason I am asking, is because we are facing the typical issues with Double buffering and vsync turned on. 
> The fps drops to 30. 

What system / setup is this and what are you trying to draw? There is no reason why double buffering combined with vsync should result in 30FPS, unless each frame takes in the range 17-33ms to draw. Does this happen also for a very simple scene?

cheers,
Gunnar


> Thanks 
> 
> Best regards 
> 
> Dietrich Gossen
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