Construct y axis rotation matrices. allegro game programming library.
#include <allegro.h>
void get_y_rotate_matrix(MATRIX *m, fixed r);
void get_y_rotate_matrix_f(MATRIX_f *m, float r);
Construct Y axis rotation matrices, storing them in m. When applied to a point, these matrices will rotate it about the Y axis by the specified angle (given in binary, 256 degrees to a circle format).
apply_matrix(3alleg4), get_rotation_matrix(3alleg4), get_x_rotate_matrix(3alleg4), get_z_rotate_matrix(3alleg4)