How do normal maps work?

OpenGL Development
#1

Does anyone know a good tutorial or intro to normal maps?

To get a smooth appearance, does the normal map have to get matched to the geometry? Or is it possible to create a generic ‘smooth normal map’? Is it possible to generate the normal map in a shader? I have semirandom terrain and I want the grass to be smooth and the rock to be rough, so I guess I have to generate the normals for the grass normal map by interpolating the verteces?

#2

I have a tutorial here, although it mostly focuses on 2D. There are some links for 3D at the end of the tutorial.

Typically you might sculpt detail using a program like ZBrush, or simply generate a normal map from something like CrazyBump. Then you apply the normal maps to your low poly terrain to create the high quality look.

#3

Thanks, I’m going to work through the tutorials!