Proteus (video game) has procedural mixing of a pre-set score based on which objects the player is near at. I suppose not much in terms of actual composition (harmony etc), but something which continues to irk me (so to speak) to try to think whether more than that is feasibly doable presently (and not only in the future).

Has there been research into this? That's a really cool concept. It's something I'd like to look into, if anyone knows any references.

I heard an interesting talk by someone who explored real-time game soundtrack composition for his dissertation: http://www.danielbrownmusic.com/artificial-musical-intellige...