I'm working on a shader that uses Tonal Art Mapping to create non-photorealistic effects. I'm able to blend the tone textures with the light intensity and map it all to screen space UV, but of course I've got the shower door effect where the tone texturing looks like an overlay on the screen. I'd like to lock the texture by applying an offset based on the object's position in screen space. I've tried a few things but I'm stumped. Can you recommend the best approach?