Re: Frambuffer configuration Onyx IR
Angus Dorbie (dorbie++at++sgi.com)
Thu, 15 Jul 1999 12:26:17 -0700
Angus Dorbie wrote:
>
> Eric Kunze wrote:
> >
> > > No, the problem is that when you use quad-buffer stereo, it appears to
> > > me that you
> > > can only use stereo channel configurations that only use 1/2 of the
> > > framebuffer.
> > > The other half is used by the (not seen in ircombine) second dualbuffers
> > > (hence quad).
> > > With old stereomode, the framebuffer is partitioned in two halfs anyway,
> > > reducing the
> > > actual vertical resolution.
> > > Can anyone confirm that?
> >
> > Ircombine will report what pixel depth you get for a given framebuffer size,
> > number of RMs combination. The channel configuration has nothing to do with
> > the visuals available. You can get stereo visuals without having any stereo
> > channels running.
> >
> > The visuals available are dependant only on the pixel depth. If you have a
> > single RM and are doing a framebuffer of 2560x1024, you are getting small
> > pixels. With small pixels, you cannot get quadbuffer stereo and multisampling
> > and Z. You can get quadbuffer stereo and Z, just not multisampling. Samples
> > require a lot of framebuffer memory.
> >
> > If you add a second RM, you can go up to medium pixel depth, which does
> > allow samples, db, stereo and Z. If you bring up the "Edit Globals" button in
> > ircombine, you can see what pixel depth a combination will have. You can use
> > the "Edit User Defined Hardware" option to see what pixel depths various #s of
> > RMs will give you. Running findvis or glxinfo -t will show you what visuals
> > are currently available.
> >
> > > Works ok for my friends (with a 4pipe "lots of RM") too, so it should
> > > work here too, the question is the following:
> > > Does multisampling uses additional FB- resources that i have to keep
> > > in mind when i try to configure it?
>
> On infinite Reality should always be able to configure multisample
> anti-aliasing with and framebuffer depth. But if you need multisample
"and" above should read "any".
> AND stereo or if you need 8 sample anti-aliasing instead of 4 then I
> expect you will need > small pixels.
>
> Cheers,ANgus.
--
Never express yourself more clearly than you think.
Neils Bohr
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on Thu Jul 15 1999 - 12:26:21 PDT