Re: Texture detail and zbuffer on Impact

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Rob Jenkins (robj++at++quid)
Mon, 20 Jan 1997 09:35:44 -0800

With 4M TRAM you can indeed have > 4bits/component textures. In summary, the
following are the supported texture formats on different TRAM configurations.

BITS/COMPONENT 4 4 4 4 8 8 8 8 12 12 12 12
COMPONENTS 1 2 3 4 1 2 3 4 1 2 3 4

1 TRAM Y Y Y Y Y Y N N N N N N
4 TRAM Y Y Y Y Y Y Y Y Y Y Y Y

If you are seeing banding on all textured applications I suppose you could have
bad TRAM - does /usr/gfx/gfxinfo actually see 4M TRAM ?

If the dithering is only on certian texturing applications only then perhaps
you need to change the internal texture format ( pfTexture::setFormat in
Performer).

When you say 'inputted these results last year to Mountain View' do you mean
you logged a support call ? If so please let email me the reference number and
I'll follow it up. If not, then maybe you could log one ( mail me the ref too
).

Cheers
Rob

On Jan 20, 10:51am, Vector Technologies wrote:
> Subject: Re: Texture detail and zbuffer on Impact
> We have upgraded a High Impact to 4M TRAM. The maximum texel depth is
> always 16 bits, that means 4bits per channel RGBA. With 16 levels per
> channel, the dithering process under certain circumstances (e.g. cloudy
> sky) even gives false colors. The patches 1447 and 1574 (under Irix 6.2) do
> not modify the behaviour. In the manual (paragraph 1.4, Indigo IMPACT
> Graphics) however 4M TRAM should come with 48 bits texel depth.
> We inputted these results last year to Mountain View, we have no feed-back
> up to now.
> Will this bug be fixed, or do we have to live on an Impact with these poor
> texel depth definitions?
> Cheers.
> Alexander Knob.
> ******************************************
> VECTOR TECHNOLOGIES SA
> 7, ch de la Venoge
> CH - 1025 St-SULPICE
> Switzerland
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>
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>-- End of excerpt from Vector Technologies

-- 
________________________________________________________________
Rob Jenkins mailto:robj++at++csd.sgi.com
Silicon Graphics, Mtn View, California, USA
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