Re: transparent textures

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Nigel Jenkins (nej++at++cs.nott.ac.uk)
Thu, 17 Jul 1997 08:28:39 +0100


Anita Kishore wrote:
>
> Anyway, the problem is that when this texture gets loaded, the neon light
> around the sign appears completely banded with each band having a single
> level of colour. The change in colour from the neon light colour to black
> (completely transparent) is not smooth at all. What else should I set to make
> it smooth?
>

I've had a similar problem using our Onyx IR, and I found that in our
case it seems to
be caused by antialiasing. When antialiasing is on you get the baned
transparency, and nice smooth lines on the rest of the model, but with
the antialiasing off you get nice smooth transparency, but nasty jagged
lines on the rest of the model!

What I think is happening (and I could well be completely wrong) is that
the antialiasing somehow reduces the colour depth during its bit of
processing, and so even though the pixel depth of the buffer you are
rendering to is the same as it is with AA off, the colours coming out of
the AA algorithm are at a much lower depth at so you get the bands.

I would be very interested to know if you find any solutions..

Nigel

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Nigel Jenkins

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