I am searching for an open source AI engine implemented in C/C++, ActionScript or Java with no success. Do you know any open source implementation?
Update: Thanks for answers! I had no idea how vast the AI field is. I am working on a sample application. I want to add intelligent behavior over a physics engine. I need some sort ai engine designed for games.
"AI engine" can mean an awful lot of different things. What kind of "AI" are you looking for?
Here is a list of some machine learning software. Many of them are open source (the linked page shows the licenses).
Artificial intelligence is a pretty big field. I'm not sure that there's one "engine" that encompasses all of AI. Do you mean a Rete rules engine? Try Drools. Do you mean a neural network approach? Support vector machines? Active or passive learning? There's no one approach.
I really like what I see in "Programming Collective Intelligence". A nice variety of techniques, written in Python.
I assume you are looking for Game AI and not Artificial Intelligence in general.
As far as I know, there is no such thing as AI engine. You have to be more specific. Do you need pathfinding? Do you need FSM? Goal-Oriented?
Other engines include RTS specific engines (OpenRTS is an open source one), first person shooters (new FPS games have their own API such as F.E.A.R.).
The most general purpose engine I can think of is Alive! the AI sandbox designed by AIGameDev.com
You should specify an AI category, anyway this is my favorite link: AI on the Web.
A very interesting presentation on the AI for games can be found here:
The tutorial will give an introduction to the area of applying AI techniques, such as learning, search and planning, to video games. It will focus on past and recent applications, open problems and promising avenues for future research, and on resources available to people who would like to work in this space.
Other than a good coverage of the theory you'll find links to a number of games (some open source like NERO & TORCS) that implement the ideas discussed.