Parallel

					_PROGRAMMING WITH OPENGL PRIMITIVES_
by Ron Fosner

Listing One

// Pass in three points, and a vector to be filled

void  NormalVector( GLdouble p1[3], GLdouble p2[3],GLdouble p3[3], GLdouble n[3] )
{
    GLdouble v1[3], v2[3], d;
    // calculate two vectors, using the middle point
    // ...