normalize_vector, normalize_vector_f - Converts the vector to a unit
vector. Allegro game programming library.
#include <allegro.h>
void normalize_vector(fixed *x, fixed *y, fixed *z);
void normalize_vector_f(float *x, float *y, float *z);
Converts the vector (*x, *y, *z) to a unit vector. This points in the
same direction as the original vector, but has a length of one.
vector_length(3alleg), dot_product(3alleg), cross_product(3alleg),
exstars(3alleg)