Flashlight?

Does any of the GS guru's know if it's possible to fake a dark/night scene that gets "lit up" by a light source around the player? I was thinking of a mask that follows him around, but that would mean a huge image to use in the level with an alpha hole in it that could cause a lot of overdraw to the scene (?). Thanks!

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*yes I know it's Torch but it's listed as Tourch