Game AI vs Traditional AI

> Why is it that we aren't seeing the bot approach to AI implanted into single player games? Why aren't we facing opponents who have their own missions/agendas in single player games, who are bound to the same controls/restrictions/exploits as yourself?

It is hard to put difficulty curves on those kind of AI, and they often are implemented to use full scale path searching to find objectives, so in games with larger maps they would either need to blind to things in the distance or consume excessive processing power.

I remember the Skarr in the original Unreal would be hunting the Nali until you came around and they would attack you. Their behaviors were amazing at the time (and honestly, they still are better than 99% of game AI) in that they would dodge, feign death, hide in cover, and act as packs when in groups to fight you.

They were also distinctly harder at the time than almost any other AI opponent. So much so that I remember a tremendous amount of complaining that their AI was too good.

> I want AI that wants to do something, like another player would, that isn't concerned with me in particular, that has it's own goals/rewards instead of just fighting me or spouting dialogue at me.

The problem with this is that not enough people would pay for the complex AI. Game are about profit motive, and sadly making sophisticated artificial worlds of intelligent bots doesn't bring home the bacon. It is absolutely possible, especially in an MMO kind of setting, since you can just throw more CPU cores to do all the complex logic for whatever fancy AI your NPCs are using, but nobody seems interested.

There's very little logic evidenced in human intelligence. What's there is a tangled web of heuristics that gets us to a good enough approximation of a reasonable action to keep us from killing ourselves (usually), but also brings calculation time way down compared to if we had to explicitly determine the rational action.

Irrational behavior is the norm. It's explicitly rational behavior that is artificial, and we choose when to mentally crunch the numbers of rationality based on our good-enough old heuristics.

It depends on your definition of fun. It can be hilarious!

I would guess that all of these bugs were known by the developer at the time of ship and not seen to be important enough to 'fix'. Bug #4 may even have been an authored response. As a player, that's exactly what I want to see happen when I throw in a flaming barrel.

> When people want AI in video games they want the AI to be truly smart.

Yes! This statement made me think immediately of Team Fortress 2 and how impressive talented spy-players are. They're so impressive that I can be in awe of a good player whether he's my ally or my opponent. Of course, the latter also comes with some frustration.

For those unfamiliar, the spy in TF2 has the ability to cloak (turn invisible) for a few seconds as well as indefinitely disguise himself as a member of the enemy team. Subtle cues give away a disguised spy--he can't run 'through' team members of the same color like true allies can; he un-disguises if he attacks. His deadliest attack is the backstab--knife someone in the back to instantly kill.

What makes good spy players so impressive is that they've anticipated how other people behave and have thought of effective countermeasures.

A troll-ish, albeit intelligent, example of such intelligence involves a spy spraying a provocative out-of-game image on a wall at a corner. He cloaks when an enemy approaches and waits near the corner. Most new players will pause when running past the image to have a closer look. The spy then uncloaks and backstabs the player.

Example: http://youtu.be/zOR3snVKW0E?t=18s

Pre-programming this sort of behavior makes it quickly predictable, unless the AI has enough variety in its 'bag of tricks' that it would take a long time to learn it all...just like playing against a skilled opponent for a long time. I'd love to see the day when game AI could discover such behaviors on its own, searching for new ones when old techniques become too common.

A hat-tip for mentioning Keldon's RFTG AI.

It's surprisingly brutal and even against good players it wins a good proportion of games. It does though show the downside of the machine learning and neural net approach (it uses a trained neural net) in that it can take a very long time to train the network and when it exhibits unexpected behavior it's almost impossible to tell why.

For those interested, all the source for the AI is on Keldon's website (linked above) - the only thing missing is the art for the cards at the publisher's request.