A problem with normals and lighting
Hi;
I'm using vb.net express and the june 2005 sdk.
I've created a simple landscape mesh in the x-z plane with a light directly overhead pointing down (vector(0,-1,0) like the sun.
I generate the normals by using mesh.computenormals.
The problem is, when I display the mesh, everything is completely lit -- there are no variations of brightness on the hills as you'd expect. So it's hard to see anything at all; the only way you know it's not completely flat is by looking at the edges.
I know the normals are there, because if I comment out mesh.computenormals the mesh is very faint, just lit by ambient light.
It's as if each normal is set to (0,1,0) -- yet I know they're not. (I examined the values; they're computed correctly. In fact I'm even calculating weighted vertex normals for very accurate lighting.)
Am I misunderstanding lighting somehow? If I change the light direction to (0,0,1) (along the +Z axis )suddenly I can see hills and valleys. But surely even directly overhead there should be some variation?
I'm really puzzled by this ....
