// In an effort to make the toon filter look more like Borderlands (which does not in fact use filters to create its aesthetic) I created this. Invert the sobel, multiply it by the existing toon shader. vec4 blackEdgeToon(vec4 sobel_colour, vec4 cel_colour) { vec4 ism = vec4(1.0 - sobel_colour.r, 1.0 - sobel_colour.g, 1.0 - sobel_colour.b, 1.0);// inverse sobel multiplier return cel_colour * ism; }