Texture compression

[vershner 11]

Does anyone know what the pros and cons are of compressing textures? Presumably there must have been a discussion about this somewhere but google doesn't seem to find one.

Obviously uncompressed textures look better and compressed ones are smaller, but beyond that is there any difference? Does it affect performance, or does the game require compression for certain types of texture?

[rsc204 21,814]

Can't be too specific as I don't know all the ins and outs, but I figured someone should respond!

Uncompressed textures will affect performance, but given a modern PC's power, I'm not really sure how much of an issue that would be. I suppose it really matters more how many uncompressed textures you are using, I could see how a complete set of them would perhaps cause trouble, but a handful, probably not. I guess this is much like using HD textures, they take more of a toll on the system as they are a larger size. Speaking as a HD fan, I don't see a huge difference in performance from having all the higher-res textures hanging about.

That said, compression is used by pretty much everybody, when used well this doesn't have a massive difference in what you see. The biggest problems have to do with the way a block of pixels (usually 2x2) is compressed by picking a match in terms of colour from them and using that for all 4.

Really the best advice here is that you aren't going to break anything by trying things out, so just play about a bit and see what happens. If the uncompressed textures look markedly better to you and don't cause the game to throw a wobbly then I'd say go for it. As for releasing them that way, I think if you did it would be better to additionally offer a compressed variant too. Not everyone runs SC4 on a modern PC, so it keeps things compatible for all.

[Null 45 3,044]

That said, compression is used by pretty much everybody, when used well this doesn't have a massive difference in what you see. The biggest problems have to do with the way a block of pixels (usually 2x2) is compressed by picking a match in terms of colour from them and using that for all 4.

The DXT1 and DXT3 formats use 4x4 blocks (16 pixels), the compression checks the color of all 16 pixels and picks the two color extremes which it converts to RGB 565 the remaining two colors are interpolated between the extremes (see Overview of DXT Compression for more information).

The amount of degradation that the compression causes depends on the image and the color matching algorithm that the compressor uses.