i’m looking for an advice about the 3 existing bump mapping techniques: emboss bump mapping, dot3 and environment-mapped bump mapping. i’ve read some articles about this issue, but i have to know which technique i can implement with OpenGL API, i think that is only Emboss Bump Mapping, but maybe i’m wrong?!?!
You can do all three. Emboss bumpmapping can be done on pretty much all cards, Dot3 only on the GeForce and up, and EMBM only the GF3 and up. All Radeons can do Dot3 as well – not sure which ones support EMBM.
Note that the original Radeon actually supports specular+diffuse bump mapping; it can configure its three texture units to do that. GF2 only has two tex units, so it can’t do that. It can do it in two passes, though.