[SDL] OpenGL speed, Linux vs W2000

Sami Näätänen sami.naatanen at kolumbus.fi
Fri Jan 24 05:17:01 PST 2003


On Friday 24 January 2003 03:08, Glenn Maynard wrote:
> On Fri, Jan 24, 2003 at 02:48:32AM +0200, Sami Näätänen wrote:
> > > 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?
> > >
> > > Now I have to correct a previous statement I made.  I now realize
> > > from looking at the output from the program that the W2000
> > > version always sets SDL_GL_DEPTH_SIZE to 16, while the Linux
> > > version sets it to 24, regardless of what I try to set it at (16
> > > or 24).  The call SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, n) seems
> > > to be redundant - commenting it out has no effect.
> >
> > I thought so. ;)
> >
> > That's why I asked if you did give the windows version "-bpp 24"
> > parameter so that it will be made 24 bpp like the X11 version.
>
> SDL_GL_DEPTH_SIZE should be irrelevant here; as someone pointed out,
> it sets the depth buffer size, not the color buffer.  Just make sure
> you're not enabling depth buffering (no glEnable(GL_DEPTH_TEST)) and
> that you're not clearing the depth buffer (no
> glClear(GL_DEPTH_BUFFER_BIT)) for this benchmark.

Well I missread it.
I thought he was referring to framebuffer depth,
which does count if you are clearing the background.





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