[osg-users] Strange limitation to 60fps

[Valerian Merkling]

Hi,

I'm working on a GIS app with QT 5.5 and OSG 3.4.0. My test platform is windows 7 pro 64bits, but i'm building my app in 32bits.
I'm currently trying to improve performance a bit and I'm facing a problem that I can't understand.

I'm using OsgQT to make a OSG Widget and draw my scene inside. This widget has a CompositeViewer, and I call its frame() function when needed (I'm not using the compositeViewer.run() function). "When needed" include the widget repaint function and a Qt Timer.

The StatsHandler shows me that I can never get more than 60.00 fps.

I'm mostly running at 59.96 or somethings like this, event with a small windows, basic textured quad and a NVidia quadro K4000. 

I made lot's of test and tweaks, and I cannot got more than 60.00fps. 
Even with a loop around the frame() call, my statshandler graph looks like OSG is waiting between each frame to keep at 60.00fps.

It's not that I really want to get more than 60fps, but I really want to understand what is happening here. 

So is there anythings in OSG that artificially limit it's framerate inside the compositeViewer.frame() function ? 

After a deep look at the code I wasn't able to find any clue, as the setRunFrameScheme and setRunMaxFrameRate seems to only be used in the run() function.

Thank you!

Cheers,
Valerian

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Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=70068#70068



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