Hmmmmmm.......well, I am just adding a comment, as I know nothing on scripting!
Making a Splinter Cell type game could be nice. But, are you asking this so you can use the dark and the light to your advantage, or your enemies' advantage, right? The light/shadows interpretion (dunno if it's spelled right) depends on gameplay. If you're making an all-out warfare game, then have shadows hiding guns, ammo, objectives, and the like. But in a spy game, the light is your natural enemy, and the shadows conceal you. Shooting out a light produces noise though, so I'd advise you not to carry a Deagle in. Take a suppresed gun, or by any chance, a glass bottle.
Breaking glass DOES make a noise though, so be cautious. If an enemy's nearby, dispose of him, then move on.
I hope this good advice helps.
AI, out.
Automatic: Biological Warfare
Comin' soon, maybe in Jan./Feb. 2007!