double sided lighting


  1. can someone tell me how i code double sided normals which point to both directions on its axis ?

  2. how do i change the shading model for both sides of a polygon? when i draw a bezier mesh with flat shading , one side is flat shaded (i think its the front) and the other side is smooth shaded.


  1. Search for the terms ‘cross product’. This is how you compute the normals of a object. Once you compute the normals going in one direction perpendicular to the object in question it should be easy to calculate the opposite normals by simply negating them.