al_set_shader_bool - Allegro 5 API

       Sets a boolean uniform of the target bitmap’s shader.

       Returns true on success.  Otherwise returns false, e.g. if the uniform by that name does not exist in the
       shader.

       al_set_shader_bool - Allegro 5 API

al_use_shader(3alleg5)

Allegro reference manual                                                             al_set_shader_bool(3alleg5)

       5.1.6

              #include <allegro5/allegro.h>

              bool al_set_shader_bool(const char *name, bool b)