Re: Generating textures on the fly

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Amaury Aubel (aubel++at++lig.di.epfl.ch)
Fri, 27 Jun 1997 20:11:29 -0600


On Jun 25, 8:05pm, Rob Jenkins wrote:
> Bit of an aside, there's a chapter of the 6.2 gl_dev relnotes:
> 'Pbuffers_on_Impact' that anyone wanting to use Pbuffers ( esp on Impact )
> would find useful.
>
> Cheers
> Rob
>-- End of excerpt from Rob Jenkins

Thanks Rob for pointing this out, it was most useful!

At last I managed to generate textures in an off-screen pbuffer with the right
alpha values, load them into TRAM, and map them onto Billboards with
transparency on. Pew! So I almost achieved my goal except that...

it won't work with a Z-buffered pbuffer!
(because it runs out of FB resources)

On our Octanes and O2s, findvis 'rgba Z' gives:

0x2b, RGBA 4/4/4/4, db, Z 24, S 8, accum 16/16/16/16
0x2d, RGBA 4/4/4/4, db, stereo, Z 24, S 8, accum 16/16/16/16
0x2f, RGBA 5/5/5/1, db, Z 24, S 8, accum 16/16/16/16
0x31, RGBA 5/5/5/1, db, stereo, Z 24, S 8, accum 16/16/16/16
0x33, RGBA 8/8/8/8, db, Z 24, S 8, accum 16/16/16/16
0x35, RGBA 8/8/8/8, Z 24, S 8, accum 16/16/16/16

What is the "size" of a pixel in 0x2b, 0x2f, 0x35?
Even if I allocate a tiny (ie 16x16) pbuffer it crashes...

My hardware config. is the following:
Graphics board 0 is "IMPACTSR" graphics.
        Managed (":0.0") 1280x1024
        Product ID 0x3, 2 GEs, 2 REs, 4 TRAMs
        MGRAS revision 1, RA revision 0
        HQ rev B, GE11 rev B, RE4 rev C, PP1 rev A,
        VC3 rev A, CMAP rev E, Heart rev D
        19" monitor (id 0x1)

        Channel 0:
         Origin = (0,0)
         Video Output: 1280 pixels, 1024 lines, 72.24Hz (1280x1024_72)

Do I stand any chance to have a Z-buffered (preferably sb) pbuffer?
Maybe if I change down the screen resolution?

Amaury.
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