The only way (i can see) you're going to do that is by processing everything that cam can see and chopping up faces, it would be a nightmare.
The reason why I say this is imagine you're looking at a T junction where you've got a corridor going to a corridor that crosses it. The back wall that you're seeing may only be a couple of triangles so there is hidden and visible stuff on the same triangles. This means working out what parts are visible and what parts aren't and rebuilding the mesh and sorting the uvs as necessary...
Good luck!
I'm sure Swift will be on the end of this post soon to give you a 14 screen explainatio :)
The reason why I say this is imagine you're looking at a T junction where you've got a corridor going to a corridor that crosses it. The back wall that you're seeing may only be a couple of triangles so there is hidden and visible stuff on the same triangles. This means working out what parts are visible and what parts aren't and rebuilding the mesh and sorting the uvs as necessary...
Good luck!
I'm sure Swift will be on the end of this post soon to give you a 14 screen explainatio :)