Re: [Algorithms] S3TC decompression software (LONG)

[Conor S. <cs...@tp...>]

> Chroma-keying worked great back in the old DOS days when everything was
> point sampled.  When you start doing filtering on your textures you start
> blending towards your key color before you actually get there, and
generate
> halos around the transparent areas.  A one-bit alpha mask can be smoothly
> blended while a key color cannot.  Generally palletized textures are a
> performance problem if you have many palettes, because you end up having
to
> load the palettes into the hardware in addition to making sure the texture
> is available.  There are trade-offs everywhere, and palletized textures
> generally end up being more of a hassle than they are worth from a
hardware
> view-point.  I also believe that nVidia is not alone in not supporting
> palletized textures, I know Rendition did not support them either, but I
> don't know about other more current hardware.

Well, there are cards that don't support S3TC that do support palettes :)
Its a nice option to have around. And not only that, I'm pretty sure you can
have alpha in the palette (OGL's paletted texture extension allows it).
Which means that one of the problems are gone. On many hardware
configurations (particularily older ones) paletted textures can give a
performance boost as well.

Sure, its a legacy feature, but it is useful (and some of us think support
for older cards is still needed).

Conor Stokes