Compositor: obtain facing from normals pass to affect glare? Is there a way to obtain the "facing" of individual pixels on a rendered image by using the normals pass?  IE: if a surface's angle points away from the camera, it becomes darker, and when a surface's angle points towards the camera, it will become brighter.

Edit: The reason I'm asking is because I'm trying to develop a custom glare node in the compositor.  Bright areas will get weak fog glow, but I also want to produce a star-like glare over bright points which are facing the camera.  I don't know whether this is accurate to reality or not, though.  If there is a better method for doing so, or to realistically accomplish the effect, I'm all ears.
This works like a dream. ridiculously simple too. the normal node can be found under vector in the add node menu(shift-a).