Ok, this may be a bit difficult to explain, but I'm looking for a single pass shader that makes all the polygons of a model invisible unless the polygons overlap, then the polygons are shown in black.

I guess you could call it an "overlap" shader, the polys should only be visible when they overlap...I'm not sure how to begin this shader though...

Very difficult. You'd have to specially draw a copy of the scene and somehow figure it out.

What's it for? There may be a better way to solve your problem?

well, i simply want to add it as an "inline" on another model, sort of a "anime" shader, like this one:



notice how the character closest to the scene has a "crease" line across his back, although I don'g have a video to prove it, the lines change as the characters move and as polygons are put over other polys. My guess is that they have a shader that does toon shading, has a small outline and has an "inline" that is the model's polys rendered in this way, where they only show up when they are on top of other polygons.

This is only a guess though, but I really want to get that "inline", I have a good toon shader "thanks to BoH_Havoc" . If you know what it could be I would also like to know

You might be able to get a similar result by using the normals. If the face is over a certain point (facing towards the camera), then it's inline.

For example, anything below 80 degrees from the camera.

I'm not sure how I would do that...I think it would be like a CW culled normal, but that it would be shown all over

I'm going to do some tests. I'll let you know what I come up with...

cool, i look forward to seeing your results. Good Luck

how did it go?

Oh yeah, sorry. I forgot about this...

It looks alright. I don't have any good models to demonstrate toon shading though. If you could send me one, I'll post some screenshots, and if useful, I'll give you the code...

All it needs is a character to show that the lines work, here take this one.