For the last few days I've taken some time off from the AI work to mess around with some graphical effects, and in particular I've been experimenting with a 2d ambient shadows effect. This is inspired by the Screen Space Ambient Occulsion (SSAO) effect which has gotten popular lately, and is largely a translation and adaptation of it into a 2d world.
To start with, here's my test scene (unrelated to the current platformer/ai work):
More images and shader code at my new journal location...