al_rotate_transform(3)     Library Functions Manual     al_rotate_transform(3)

NAME
       al_rotate_transform - Allegro 5 API

SYNOPSIS
              #include <allegro5/allegro.h>

              void al_rotate_transform(ALLEGRO_TRANSFORM *trans, float theta)

DESCRIPTION
       Apply a rotation to a transformation.

       Parameters:

       o trans - Transformation to alter

       o theta - Rotation angle in radians

SEE ALSO
       al_translate_transform(3), al_scale_transform(3), al_build_transform(3)

Allegro reference manual                                al_rotate_transform(3)