[SDL] OpenGL speed, Linux vs W2000

Glenn Maynard g_sdl at zewt.org
Thu Jan 23 13:50:01 PST 2003


On Fri, Jan 24, 2003 at 09:35:51AM +1300, Gib Bogle wrote:
> > See what happens if you use a 1024x768 window in Windows.  Linux might
> > be blitting on flip instead of page flipping (which would be a bug).
> 
> Very interesting.  If I remove both SDL_FULLSCREEN and SDL_NOFRAME from
> video_flags in the W2000 version I get 690 fps.  Removes either one
> alone has no effect.  Do you think this means there might be a Linux
> bug, and do you mean in SDL or X?

If nothing else is onscreen--if the entire screen is your app--the back
and front buffers can be switched instantly in hardware.  This happens
when you're fullscreen, and it also happens if you use SDL_NOFRAME and
the window is as large or larger than the screen.  This is mandatory for
acceptable performance at higher resolutions.

(Don't count on the latter SDL_NOFRAME behavior; I'd only expect most
platforms will only do hardware page flipping if SDL_FULLSCREEN is set.)

X may not be correctly page swapping in fullscreen for some reason.

-- 
Glenn Maynard




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