Diffuse Color in Post Processing for Mobile


I’m trying to achieve a cel shaded look for a mobile game. But all tutorials for cel shading post processing materials use “Diffuse Color” which isn’t available on mobile. Do you have an idea for a workaround?
Maybe through the dot product method. But I can’t find any tutorials on how to make a cel shader using the dot product.

Thank you very much!

I’am also very interested in a workaround for this.

Did anyone end up finding a workaround?