ALLEGRO_SHADER_PLATFORM(3) ALLEGRO_SHADER_PLATFORM(3)

ALLEGRO_SHADER_PLATFORM - Allegro 5 API

#include <allegro5/allegro.h>
typedef enum ALLEGRO_SHADER_PLATFORM ALLEGRO_SHADER_PLATFORM;

The underlying platform which the ALLEGRO_SHADER(3) is built on top of, which dictates the language used to program the shader.

ALLEGRO_SHADER_AUTO - Pick a platform automatically given the current display flags.
ALLEGRO_SHADER_GLSL - OpenGL Shading Language
ALLEGRO_SHADER_HLSL - High Level Shader Language (for Direct3D)
ALLEGRO_SHADER_AUTO_MINIMAL - Like ALLEGRO_SHADER_AUTO, but pick a more minimal implementation that may not support alpha testing.
ALLEGRO_SHADER_GLSL_MINIMAL - Minimal GLSL shader.
ALLEGRO_SHADER_HLSL_MINIMAL - Minimal HLSL shader.
ALLEGRO_SHADER_HLSL_SM_3_0 - HLSL shader using shader model 3_0.

5.1.0

Allegro reference manual