VMD-L Mailing List

From: Alexander Farley (afarley_at_mail.med.upenn.edu)
Date: Sun Sep 08 2002 - 09:36:48 CDT

Hello,

        I want to confirm that quad-buffered stereo works on ATI (Sonic Blue,
Diamond etc.) FireGL 2 (and 3/4) cards in linux running VMD using
Stereographics glasses. It of course requires the DRI/OpenGL version.
The qbs had to be enabled manually in the XFConfig file rather than by
the configuration program. I does not appear to require high-refresh
rates (i.e. above 120 kHz and pixel clock above 220) as in
page-flipping, but I could be wrong as my monitor can handle this (see
below about wasting money).
        I would strongly suggest this card to anyone who really wants hardware
acceleration/rendering and stereo in linux. I wasted a lot of time and
money before getting to this card. I know that it may not be the "best"
card in terms of performance (it's price is pretty good though) compared
to nVidia. However, it does not requires nVidia's extra kernel and
OpenGL crap. Once I learned that the same compiler and libraries needed
to be used for the running kernel and the firegl23 module everything
worked perfectly.
        Additionally it appears that all future FireGL cards will support
quad-buffered stereo and linux. Of note, it seems that the main reason
the ATI supports linux is that the drivers were inherited (from Sonic
Blue) and that the chipset was originally intended for Unix systems (IBM
p-series running AIX) and may have already had code available when
Diamond or Sonic Blue started to make the cards for PC. HP may also have
something to do with the driver as I think the cards were used in the
linux systems that they sold to Dreamworks in 1999(?). I could be wrong
about all of this, but it explains some of the anomalous features of the
card in linux.
        To go on a short rant, it appears the main reason that there is a
severe lack of good graphics drivers (and then by extension good
graphics/CAD programs) is the GPL and the legal conflict of having
proprietary code touch the kernel. That and the ever changing
configuration of each user. I think if there was some type of resolution
that companies would be more willing to offer better drivers (save for
Matrox which already does, but there cards are not 3D anyway).
        Also for other cards I would stay away from XiG drivers. I have only
had problems with them (and they cost a lot). There OpenGL compliance
seems to conflict with the non-OpenGL compliance of many Mesa/linux 3D
programs. Not to mention that it is impossible to change the code if
there is some type of minor problem, since there is no code.
        One last note is that I have read that the whole linux-stereo issue may
be moot with certain technologies. Along with DTI, a lot of companies
are producing LCD auto-stereo monitors. One company even has a
completely passive system where-by two LCD screens are layered giving
the illusion of depth to everything. Alas I do not remember the name of
the company, but the product is not that far off and the prices seemed
reasonable; only 75%-100% more for what amounts the two LCD monitors.

Alex Farley