QuoteYou are drawing the edges of the cube and not the faces of the cube what i wanted to say is that you have to draw each edge twice. otherwise you dont know wich normal you have to assign to the vertices of the edge. have a look at how glut does it. (Link).by AlfredMantalini - Coding
I think the problem is how you draw the wireframe cube. You are drawing the edges of the cube and not the faces of the cube. See, the way you draw it each line (edge) is shared between two different faces of the cube. That makes 2 normals (actually 4, one pointing inside and one pointing outside for each face) to choose from for your vertices. What ever normal you choose, it will look wrong for oby AlfredMantalini - Coding