lighting

A good approximation of per vertex normals is averaging the normals of the surfaces which share the vertex. Make each vertex have space for a normal, then do something like this:

for each triangle  get vertices v1, v2, v3  find normal N by cross product (keep the winding order in mind)  add N to the normal of v1, v2, v3for each vertex  normalize the normal

/edit: About understanding how the normals work, draw a surface with normal on a piece of paper and note how the illumination varies with the dot product of the normal and direction of incident light.

Using vertex normals means that the illumination is calculated at each vertex, and the color can be interpolated across the surface of the polygon. This results in smooth (gouraud) shading.

http://nehe.gamedev.net/

still the best source for opengl newbies :)

ok guys, thanks. now I really got the idea.