I feel like an idiot. What im trying to do is light a terrain using per-surface shading. Ive looked in MANY other posts and sites but none of them clear up my confusion, maybe you can help.

To draw my terrain I use triangle strips but only declare 2 verticies, to be honest I dont know how you get a triangle from 2 vertices but its on most sites and it works so I use it.

Ive read to get normals to get a 2 vectors from 3 different verticies on a triangle, but im confused. You're supposed to do v[0] = v1 - v2 and so on. But I thought a vertice consisted of 3 variables - a x, y, and z coord. So how would you subtract 2 vertices consisting of 3 coords each?!?! or is it supposed to be v[0] = x - y: like that?

Ill do whatever it takes; if you think posting my code up here would help let me know!

THANK YOU!!!