From: Magnus Kreth (
Date: Mon Jan 13 2003 - 09:32:28 CST


first, I'd like to say a big thank you for your efforts. VMD really is a
great piece of software.

We use a PC with a NVidia Quadro4 900XGL graphics adapter. After installing
the drivers released by NVidia in Sep. 2002 we succeeded to use the
Quadbuffered OpenGL stereo feature in most of our applications including
PyMOL. However, VMD still does not like our configuration. Attached is the
output of "glxinfo -t". I'm not an expert, but to me it looks like their are
plenty of visuals with stereo support. Nonetheless, the output of VMD does
not contain STEREO in the list of OpenGL extensions. Starting VMD gives
the same output as reported by K. Suhre.

Am Dienstag, 7. Januar 2003 16:42 schrieb John Stone:
> Dear Karsten,
> The fact that you don't get "STEREO" in the list of OpenGL extensions
> indicates that your card can't do both stereo and multisample antialiasing
> simultaneously. You might see if you can make changes to the NVidia
> environment variables to disable antialiasing, that should free up enough
> video memory to allow you to use stereo. VMD is a bit trickier than
> programs like O, in that it wants a number of OpenGL extensions, some of
> which are mutually exclusive. In the case of the NVidia drivers on Linux,
> it can end up with antialiasing but not stereo as a result of the way the
> NVidia drivers are written presently. If you're unable to force the NVidia
> driver to disable antialiasing in favor of stereo, let me know and I can
> give you a version that'll give stereo higher priority than antialiasing.

I tried to disable antialiasing by "export __GL_FSAA_MODE=0" prior to
starting VMD as written in the file README in the NVidia driver package. This
does not help. It doesn't even change VMD's output upon startup which still
contains "MSAA(4)" (which means multi-sample antialiasing?).

Any further help to get stereo working would be very much appreciated.

> Thanks,
> John Stone

Thank you!

Magnus Kreth

> On Tue, Jan 07, 2003 at 12:32:22PM +0100, Karsten Suhre wrote:
> > Hello!
> >
> > I am trying to get VMD (latest version) running in stereo mode using an
> > NVIDIA Quadro4 750 XGL graphics card under SuSE Linux 8.1 using the
> > latest NVIDIA driver.
> >
> > My card should be working properly in quad-buffered mode, since I can
> > view stereo images using O correctly.
> >
> > When I start VMD, I get the following messages:
> >
> > Info) OpenGL renderer: Quadro4 750 XGL/PCI/3DNOW!
> > Info) Features: STENCIL MSAA(4) RN MTX TCM
> > Info) Textures: 2-D (4096x4096), 3-D (512x512x512), Multitexture (4)
> >
> > However, when I try to switch to "CrystallEyes" in the Display pull-Down
> > menu, I only obtain two separate pictures of my molecule (one above the
> > other, as without a stereo board).
> >
> > Am I missing something (e.g. setting some environment variable)???
> >
> > Thank you very much for any suggestion,
> >
> > Kind regards,
> >
> > Karsten Suhre.