Yeah, I was doing some more poking around and found this article on AMD’s website. They’re using a kind of light probe system that measures the incoming light and then reflects it back into the environment, which fits with my original assumption that it was a fairly generalized system.
But even so, the generalized light bounces in enclosed indoor spaces like that work pretty darn well even if they’re not able to handle points of contact (plus it runs smooth as butter and is a nice example of something that a game has actually shipped with).
I’m still interested if some kind of generalized system like this based off light probes (or reflection captures?) could be implemented.
Left has no radiosity/GI, while the right has it enabled.
https://community.amd.com/servlet/JiveServlet/showImage/38-1134-2064/ai_radiosity.png
https://community.amd.com/servlet/JiveServlet/showImage/38-1134-2062/ai_radiosity2.png