apply_quat - Multiplies a point by a quaternion. Allegro game programming library.

       Multiplies  the point (x, y, z) by the quaternion q, storing the result in (*xout, *yout, *zout). This is
       quite a bit slower than apply_matrix_f(), so only use it to translate a few  points.  If  you  have  many
       points, it is much more efficient to call quat_to_matrix() and then use apply_matrix_f().

Allegro                                           version 4.4.3                              apply_quat(3alleg4)

       apply_quat - Multiplies a point by a quaternion. Allegro game programming library.

#include<allegro.h>voidapply_quat(constQUAT*q,floatx,y,z,*xout,*yout,*zout);