// Aliased checkboard pattern discarding "white"
// loosely based on orange book chapter 11.3

void main() {
	if (gl_TexCoord[0].x > .5) {
		if (gl_TexCoord[0].y > .5) {
			gl_FragColor = mix( gl_Color, vec4( 0,0,0,1 ), .5);
		} else {
			discard;
		}
	} else {
		if (gl_TexCoord[0].y > .5) {
			discard;
		} else {
			gl_FragColor = mix( gl_Color, vec4( 0,0,0,1 ), .5);
		}
	}
}
