void normalize(float v[3]) {
GLfloat d =
sqrt(v[0]*v[0] + v[1]*v[1] + v[2]*v[2]);
v[0] /= d;
v[1] /= d; v[2] /= d;
}
void normCrossProd(float u[3], float v[3], float
out[3]) {
out[0] =
u[1]*v[2] – u[2]*v[1];
out[1] =
u[2]*v[0] – u[0]*v[2];
out[2] =
u[0]*v[1] – u[1]*v[0];
normalize(out);
}