How could i modify texture coordinates to achieve, for example, a fire effect ?

Not sure what you mean. There are many ways of playing around with textures - sphere mapping, blitting. Random changes in tex coordinates could be a solution for what you want to do. But if you want to produce a fire effect i suggust you use a particle engine. You could also do what wetta did (in LOTR) and use an avi mapped to each particle - it produces a fairly convincing effect.

Heres what i mean by avi particle engine - went a bit overboard on the fire though

That would be a nice approach, but is it possible to have an alpha channel so that black spots of the .avi file would be transparent ?

Ive searched the web but i didnt find anything saying that u can use 32bit AVI files. If u really cant, you could have a RGBA texture and modify every frame before upload (when R, G, B are 0, set A to 0 else set A to 1).


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Excuse my poor english!

There is nice fire FX on nvidia''s dev pages. But probably a bit to heavy for you right now.
Or you can load slices(frames) of fire animation in one 3D texture and use 3rd texture component as time. This way you get free smooth blending.

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