Is It Possible to Have Multiple envmaps? blends? etc?

[CarthOnasty 214]

I'm not sure how to best describe this, but here goes. Can more than one effect be applied to a model in the .txi file?

 

e.g. Can I have envmaptexture CM_Whatever AND blending additive? Can and would more than 1 alpha channel have to be used? TYIA.

[VarsityPuppet 1,085]

I think that will work, thing is it will apply the additive blending to the cm_texture itself. I think I've tried it before, but I don't remember what the result was.

[DarthParametric 3,782]

Blending additive is a semantic used for transparency, not envmaps. Refer to - http://deadlystream.com/forum/topic/5992-tpc-compressed-texture-transparency-alpha-blending/

 

You can only have a single alpha channel. Multiple alphas is really only a thing in programs like Photoshop. I don't know of any game engine that handles that (or even what image format supports it, beyond a PSD or nearest open source equivalent).

[JCarter426 1,214]

Every game I've ever seen that requires multiple channels for something resorts to using an extra texture with the red, green, blue, and alpha channels used for different things as needed. That includes KOTOR, which uses extra RGB channels for bump maps. This is mostly down to, I imagine, there being no general need for an image format with more than four channels. Since you get all the color you want with R, G, and B, and you can get transparency or whatever else you need with alpha, and if you really need more than that you resort to using a second image with up to four additional channels because that requires the least effort. KOTOR resorts to that for the bump maps so it's inconceivable that it would let you conjure up a fifth channel for something else. What it would let you do, though, is apply a second texture to the model, like a bump map or a lightmap, but I imagine you'd have to work within the restrictions for how those work - I'm not sure if you could corral them into applying a second shader... seems unlikely.

 

There are other options depending on what you need. It is possible to make new cube maps. Though there aren't many who have attempted it and I'm not among them. If you're looking to have a shader but you also need transparency, you may be better off editing the model to split the parts you need into two different textures.

[DarthParametric 3,782]

That includes KOTOR, which uses extra RGB channels for bump maps.

That's because they are tangent space normal maps. It's a single RGB map comprising one channel per vector, not three separate greyscale bump maps.

[JCarter426 1,214]

Right - one channel is flat, one raised, one lowered (or something like that). But the point is it does need a second texture for that. 7 channels, 2 files. Sadly there's no mystical 7-channel file.