Doom3 Rendering Techniques: Meshes Casting Shadows on themselves...
 

and their environments.

Does anyone know the technique used to do this? I have been searching for it with no luck for a while now. I know how to do regular shadows, but only in limited situations. IE I can have a mesh cast an accurate shadow on the floor, but when I draw each triangle of the mesh itself I have no idea whether it is obstructed from a light source by some other triangle in that mesh...

It's a farking cool trick...