/* Shader for blitting of the luminance channel (red channel):
 * (w)2006 by Mario Kleiner. Licensed under MIT license.
 */

#extension GL_ARB_texture_rectangle : enable

uniform sampler2DRect Image;

void main()
{
    vec4 incolor = texture2DRect(Image, gl_TexCoord[0].st);
    gl_FragColor.a = incolor.a;
    gl_FragColor.rgb = incolor.r;
}