From: Tom Flynn (flynnt++at++cthulhu.engr.sgi.com)
Date: 05/24/2000 14:29:19
On Wed, 24 May 2000, Angus Dorbie wrote:
> This cannot work with a single app right now.
>
> It might be possible by running two copies of Performer as separate
> applications but you need DRI based drivers to handle the dispatch of
> OpenGL to the right card with this type of config
slight correction here...currently neither DRI or Nvidia drivers handle
multiple cards. Both drivers are designed so that such a thing could be
possible, but it has yet to be implemented.
> and the nVidia drivers
> don't use that framework but use their own fast dispatch method so you'd
> need to mess around with which different version of OpenGL libs that the
> two copies of Performer linked to so that the nvidia display got
> hardware acceleration via the SGI nVidia drivers and the voodoo's (SLI I
> assume) worked via the DRI drivers.
>
> This is my best guess as to what you need to do, I haven't tried this, I
> expect you'll be the pioneer if you proceed with your plan.
>
> The stereo will be horrid since there will be no sync of refresh, swaps
I don't believe stereo is supported in either driver at this time. As to
swap on vertical retrace, that can be enabled via an environment variable
(GL_SYNC_TO_VBLANK) on our 230 systems. I don't believe the DRI driver
currently supports swap on vertical retrace.
> or update. You could do a little bit in software through shared memory
> but you's will at least like to block on frame completion before the
> swap probably just after pfDraw and that will slow you down.
This really needs to be done inside the driver where you can have control
over when data gets sent down the FIFO. You might be able to fudge
something using the SYNC extension to XFree86, but it might be
difficult to make sure OpenGL is sync'd as expected. Again, this should
really be done in the driver.
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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