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Rob Lemmens

FPS sticks at 58/60 fps

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Rob Lemmens    122
does anyone know how it''s possible that when i render a terrain of approx. 50.000 polys i get a rate of 58/60 frames per second. When i render nothing, i get the same framerate. Could this be because OpenGL waits for a start of a new vertical retrace?? If so how does one disable/solve that?

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RoTTer    444
I think you have to check the cfgs in the driver of your video board.
I changed mine a few days ago on the wait for vsynch thing... I found it there on Control Panel -> Video -> Adapter -> Settings... or something (Im @ university right now, dont have access to open Control Panel heh)
It was saying "On By Default"
So I changed to "Always Off"
My FPS changed from 38 (would never change from 38) to 40-60 (very unstable).

Hope that helps, cya,
-RoTTer

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MattB    122
I think you''re right, the frame rate is probably limited to 60 FPS by the vertical sync. If I''m not mistaken, this happens when you call SwapBuffers. The easiest way to get around it is to disable vsync in your video card''s display preferences.

If you''re programming for Windows, you can turn the vsync on and off in code using the WGL_EXT_swap_control extension. Check out the extension registry for details:

http://oss.sgi.com/projects/ogl-sample/registry/EXT/wgl_swap_control.txt

- Matt

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Jindocai    122
Remember there is no advantage of rendering more than 60 fps if your refresh rate is 60hz since you won''t be able to see any noticable difference. It of course is a good way to see how ''fast'' your engine truely is. Also try lower res, most monitors support 70,85, even 120hz at various resolutions. Even old monitors should be able to run 640x480@85hz. Of course it is often good to limit fps even on fast machines with fast monitors (technically that''s what they are) to allow you to use the extra processesing power to do other stuff.

Beware however with messing with refresh rates that if you set your resolution to a refresh rate your monitor doesn''t support you will be flying blind unless you have an easy way to change back to a supported res or reset.

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