How do games like Rayman Legends or Mario Galaxy 2 do effects like checking your character position to see if it is in a particular light source that is dynamically blocked or unblocked? I'm trying to wrap my head around how to connect the gameplay side vs the graphics side of it. I know at least in Mario Galaxy 2 they use the frame buffer, but I'm not sure what that entails. If anyone can point me to articles or links? I would greatly appreciate it.