That's basically what I've been trying so far. I managed to get code that works when the sprite is facing 0. It fades just right depending on the cameras angle. However when the sprite is facing a direction other than 0, the fade messes up when the camera angle hits certian points (like 1~360, or 179~-180 it seems)

Got a lot more debugging in place now so I can watch my vars closely, maybe now I can rewrite it again and get it working.