#version 330
#extension GL_ARB_shader_subroutine : require
#extension GL_ARB_explicit_uniform_location : require

out vec4 fragColor;
subroutine vec4 color_t();

layout(location = 5) subroutine uniform color_t Color;

subroutine(color_t)
vec4 ColorRed()
{
  return vec4(1, 0, 0, 1);
}

subroutine(color_t)
vec4 ColorBlue()
{
  return vec4(0, 0, 1, 1);
}

void main()
{
    fragColor = Color();
}