   normals
  I am confused between these two methods of defining normals:1) 3 triangle vertices, all have the same normal, which is the same as the face normal.2) 3 triangle vertices, all have thier own normals, which is a direction relevant to the origin. When averaged the result is the face normal.I've always used 1 and it seems to have proper results in my lighting. When do we use 2?Reason I ask, is if I use 2 for my generated sphere, I can use use a index buffer to save on data passed, where I cannot if I use 1. Method 1 results in the shared edges needing seperate vertices.   
  Use 2 when the surface is curved like the case of a sphere.In the case of a sphere, each normal is normalize(vertex_pos - center_pos)   