ALLEGRO_SHADER - Allegro 5 API

       An  ALLEGRO_SHADER(3alleg5)  is  a  program  that runs on the GPU.  It combines both a vertex and a pixel
       shader.  (In OpenGL terms, an ALLEGRO_SHADER(3alleg5) is actually a program which has one or more shaders
       attached.  This can be confusing.)

       The source code for the underlying vertex or pixel shader  can  be  provided  either  as  GLSL  or  HLSL,
       depending on the value of ALLEGRO_SHADER_PLATFORM(3alleg5) used when creating it.

       ALLEGRO_SHADER - Allegro 5 API

       5.1.0

Allegro reference manual                                                                 ALLEGRO_SHADER(3alleg5)

              #include <allegro5/allegro.h>

              typedef struct ALLEGRO_SHADER ALLEGRO_SHADER;