Hi, I have some questions about offset bumpmapping.
What I have understod so far is that you need a heightmap in this algorithm, but what if you generate a normalmap from a hi-res model? Then you just got a normalmap and no heightmap?
To see the effect of this technique I should use the offset texcoord to lookup the diffuse texture. But I don’t have a diffuse texture, I just use the normalmap alone. Can this technique improve my work anyway?
Yep, you need a height map for it to work. You calculate the offset and then sample whatever textures you’ve got with the new tex coords (so it’s useful even if you only have a normal map).
I have never tried this with just a normal map, but I don’t think you’ll get as much benefit as you would if you use a diffuse texture. After all, you don’t directly see a normal map; you only see its effect in the lighting. But you do directly see the diffuse texture.
But don’t worry, you can use ORB to generate the height maps too.