Dio said:
The funny thing is I'd agree that Xbox isn't that much more powerful than PS2, but I'd disagree that nobody notices the difference. I find the texture quality on PS2 games is generally poor. Not licensing S3TC was a truly massive mistake.
(I was astonished to find that a texture palettisation utility reviewed in Develop was used "on 90% of last year's top fifty games". Palettisation should be dead as the dodo, given that DXTC is half the size and - in the vast majority of cases - hugely better quality.)
AFAIK it is not as black and white as the above quote claims.
CLUT textures have some abilities the other compression schemes does not.
* Even 4bit CLUT has alpha.
* The result of the compression is very predictable.
* Pulsing and wave animations can be done by only reloading the small LUT, even bump-mapping can be done on static geometry that way.
* 8bit CLUTs can look better than 16bit or even 24bit textures (with alpha), because you can assign up to 256 hues to a single colour if so desired, something that is not possible with only 4 or 6 bits for RGB.
The disadvantages of CLUTs on PS2, is that they are slow to load, that size of the LUT (a disadvantage that become smaller the larger the texture is), and then of course, the limited amount of colours/entries.
The first disadvantage can be alleviated to a large extent by swizzeling the texture (as I understand it, it involves basically preparing the texture so it fits the geometry without the need for conversion).
The third disadvantage is most serious for 4bit, but most realworld textures, such as wood or skin only have very few colour variations anyway (any gradual changes in tone can be more efficiently with vertex shading).
8bit textures shouldn’t need to much dithering, if the texture is below 512x512 (try to make a GIF file of an arbitrary lo-res picture)
From what I can see S3TC or DXTC, only has significant advantages if the source material is a large photo or similar.
Another thing is that geForce up to GF3 (that includes NV2a) is known to have a broken implementation of the DXT1 compression mode.
From what I've read, the disadvantage ranges from unusable to flawed, so I'm not so sure xboxs texture compression is a significant advantage if it can only realistically use DXT5 (8bit).
Fafalada said:
And like noted before, working within memory constraints as small as 32MB 8bit maps are a luxury that you can rarely afford.
Why not? A 256x256 8bit only take up ~ 65Kb. Even if you only have, say 4Mb per frame, that's sixty-three high resolution textures in one frame!
), but if it will continue to cost them $50 (or howevermuch), and be primarily useful to the Live service, they may yet want to excise the cost from the base console, and attach it to Live's requirements instead--since everyone signing up already has to purchase an extra package.
