al_set_shader_matrix - Man Page

#include <allegro5/allegro.h>

bool al_set_shader_matrix(const char *name,
   const ALLEGRO_TRANSFORM *matrix)

Sets a matrix uniform of the current 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.

5.1.0

al_use_shader(3)

al_use_shader(3).