bump mapping

bump mapping is not easy at all.

the better it looks, the hard it is. But thats always the case.


Things you should know:

texture tangent spaces. These are one of the most confusing parts by far.
Pixel and vertex shaders more than likly. You need to know these inside out.
Normal mapping. You need to understand the pricinpal of this. Both world and tangent space normal mapping.
light models (diffuse dot products, half vector specular, etc)

A good way to start is to do vertex lighting, but do multi-pass vertex lighting first. So each light does it's own additive pass. This will help later as getting this to work alone isn't easy. (efficiently )

[edit]
this of course is assuming you want quite complex 'real' bump mapping. 'fake' bump mapping - such as emboss bumpmapping is also quite tricky.. Nehe has a tutorial on it somewhere...

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[edited by - RipTorn on November 24, 2003 6:50:41 AM]

Try these sites:

http://www.paulsprojects.net/tutorials/simplebump/simplebump.html
http://tfpsly.planet-d.net/english/3d/pplight_bump.html

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"If it looks good, it is good computer graphics"
"If it looks like computer graphics, it is bad computer graphics"

Corrail
corrail@gmx.at
ICQ#59184081

well effect is so cool that i must learn how to do it...i saw paul''s simple bump mapping example and it satisfies my needs,it aint easy...

People always come to think to make complex 3D effects without really knowing the work needed behind.

First things first.

1- get to master OpenGL''s per-vertex lighting mechanism. You will absolutely need to know exactly how it is done per-vertex before goind into per-pixel lighting otherwise you will mess up everything.

2- learn per-pixel lighting (aka PPL). bump-mapping requires per-pixel lighting, so start with PPL first.

3- learn normal-mapping. There are two kinds of normal-mapping : normal replacement and normal perturbation. bump-mapping approaches use either the former or the latter, so it''s good to know both.

4- bump-mapping should be straight-forward once you know per-pixel lighting and normal-mapping. Just add a little of per-fragment computations like dot3 and you''re done.

I recommend the very good article at http://developer.nvidia.com called Robust Bump-Mapping for today''s hardware (well, ''today'' was two years ago when the article was written).
It is focused on register combiners, but it''s pretty easy to port it to ARB extensions. At least, all the mathematical theory is explained pretty clearly and helps alot understanding how and why it works, and what are the restriction why sometimes it looks a bit unperfect. If all articles were as well written as this one, computer graphics would be much easier