uniform sampler2D texUnit0;
uniform float column_width;
void main(void) {
vec3 color = texture2D(texUnit0, gl_TexCoord[0].xy).rgb; float column_index = gl_TexCoord[0].x / column_width; int ci = int(column_index); while(ci >= 3) { ci -= 3; } // % doesn't seem to work gl_FragColor.rgb = color * 0.125; if(ci==0) { gl_FragColor.r = color.r; } if(ci==1) { gl_FragColor.g = color.g; } if(ci==2) { gl_FragColor.b = color.b; }
}