Re: Buffer swapping

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From: Tom Flynn (flynnt++at++engr.sgi.com)
Date: 10/22/2001 15:30:27


in csh or tcsh:

setenv __GL_SYNC_TO_VBLANK 1

in bash or ksh:

export __GL_SYNC_TO_VBLANK=1

-tom

On Mon, 22 Oct 2001, Michael Logan wrote:

> Hi everyone,
>
> So what is the final pfAnswer to this?
>
> I have a Dell Precision530/Quadro2-Pro/Linux-RH7.1 and it tears all over
> the place at any resolution (1024x768,1280x1024,1600x1200).
>
> My Performer is 2.4.2-2 with
> nvidia drivers GLX-1.0-1190 & nvidia71 (from red-hat).
>
> Is there an environment variable? Is it my red-hat drivers? Is
> it my imagination? Clearly there is some kind of synchronization
> problem for my performer town...
>
> BTW, I saw the graphics cluster posts from Ken and went over
> to see it since Ken is in the building right next to me. He's
> right - it IS very cool. But I saw the same tearing there too...
> Different problem??
>
> ml
> --
> Michael Logan
> Raytheon ITSS
> Human Factors Research Lab
> NASA Ames Research Center
> mlogan++at++mai.arc.nasa.gov
>
>
> Tom Flynn wrote:
>
> > On Thu, 27 Sep 2001, Yves Strube wrote:
> >
> > > I also know that Performer needs the GLX extension GLX_SGI_video_sync to
> > > really detect the vertical sync. The NVIDIA driver does not implement
> > > the server side of this extension so that it is not reported to
> > > Performer.
> >
> > the client-side extension checking is fixed in pf 2.4.2. in the case of
> > GLX_SGI_video_sync on NVidia, it doesn't matter because
> > glXWaitVideoSyncSGIX() doesn't work correctly anyway (it returns
> > immediately no matter what you give it if I remember correctly), so
> > currently, the use of that extension is diabled for NVidia hw.
> >
> > performer uses this extension for frame-rate control and not buffer
> > swapping. buffer swapping is done via glXSwapBuffers(). it is up to the
> > GL driver to actually swap on vertical retrace.
> >
> > > 1. Does anyone else observe these cuts in the rendered image?
> >
> > The tearing you're seeing is possible on NV10 and NV10gl (GeForce 256 and
> > Quadro) because it's emulated in software. NV15 (GeForce2 GTS), NV11
> > (GeForce2MX), and higher have hw support for sync on vblank and it should
> > work correctly.
> >
> > hope that helps,
> > tom
> > --
> > "Mongooses are famous for their snake-fighting ability, and are
> > almost always victorious because of their speed, agility, and timing
> > and also because of their thick coat."
> >
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> > -----------------------------------------------------------------------
>
>
>

--
"Mongooses are famous for their snake-fighting ability, and are
 almost always victorious because of their speed, agility, and timing
 and also because of their thick coat."


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