I have got the polygon representation of one NURBS surface by gl feedback mechanism. Could I convert these polygons into triangles or directly convert NURBS surface into triangles?
I believe that such polygons will be convex, so you can split them easily in triangles.
i.e : polygon with vertices 0,1,2,3,4 (pentagon)
-> triangle 1 : 0,1,2
-> triangle 2 : 0,2,3
-> triangle 3 : 0,3,4
and you are done.