The Sloped Playing Field

Often when programmers get together to talk about AI for computer games , they concentrate their discussions on how they want their AI agents to be on equal footing with the player. This was certainly the case at the AI roundtables I have attended in years past at the Game Developers Conference. These AI specialists want their AI systems to know only what players would know, see what players can see, and so forth. This, they suggest, will make the conflict between the AI and players more realistic and therefore more interesting.

Of course, for years games have been giving the AI agents unfair advantages over the player. They have made the AI have more hit-points than the player character. They have outnumbered the player a hundred to one. They have made the AI agents have a practically psychic knowledge of every location in the game-world, which allows them to know exactly where the player character is at any given second, certainly an unfair advantage. Some game AIs have even been known to cheat. Surely this is unfair to the player, the AI programmers will say. They proclaim the AI should be on equal footing with the players and should triumph through its wits alone.

But is it really better to put the AI and players on a level playing field? First and foremost, this is quite likely to lead to AI that fails to provide much of a challenge for players. The fact remains that shrewd players are going to be able to outsmart even the most sophisticated game AI without that much difficulty. Trying to put players and AI on equal terms will create a much larger challenge for your AI programmers. They will need to invest countless more hours in developing an AI that has even a slight chance of beating the players, time that cannot be spent improving other parts of the game. In the end they may well end up with an AI that does not provide a captivating gameplay experience. In the worst case, the AI is too busy being real to avoid performing blatantly stupid actions.

A big part of what drives AI programmers to attempt a level playing field for players and AI agents is the programmers own egos. These programmers pride themselves on their work and will assert that they can come up with an AI that will be able to challenge players without having to resort to superior numbers , greater strength, or any sort of cheating. The programmers want the bragging rights of being able to say that their AI is as smart as a human. Often hours and hours are spent trying to come up with the sophisticated algorithms required for such equal versus equal competition, and in the end something has to be hacked together to make the game actually function. The goal of game AI is to support the game and enhance players experiences, not to serve as a test-bed for artificial intelligence techniques.

Besides, there is something romantic for players when they manage to defeat an AI opponent despite the fact that the AI s forces greatly outnumber their own, were better armed and equipped, and even had the benefit of prescient knowledge of the map. Just as the Hollywood action hero triumphs over countless foes, players want to overcome seemingly insurmountable odds for their own victories. Tipping the scales in the AI s advantage only makes players eventual victory all the more sweet. Unless, of course, the design ends up making the game too hard.

How Real Is Too Real?

Another potential AI programming pitfall is creating an AI that, though it actually performs like a real person, ends up detracting from the gameplay as a result. In terms of the stories they tell and the settings they employ , games are often contrivances, strictly unreal situations that are specifically set up because they are interesting, not because they are authentic , and the AI must support this.

Consider the James Bond movies. These films are like many popular games in that they feature a lot of action and exciting situations with less of a focus on character development or meaningful stories. In nearly every film, Bond is captured at some point and tied down to a particularly hideous execution device. This device does not kill Bond instantly, but instead employs some slower method, such as a laser steadily burning a hole down the middle of the table to which James is strapped. Why does the villain not simply shoot Bond? Or simply aim the laser straight at him? Why does the villain almost always leave before the execution has actually been completed? And why does the villain reveal to Bond his entire mad scheme for world domination before he starts the execution device in motion? None of these choices are indicative of especially smart behavior, but it is fun to watch, and fits with the overall style of the movie. It entertains the audience, which is the primary goal of the Bond films. Realism is much less of a concern.

And so it is with games. If the enemy AI is so smart, surely it should realize that it has no chance against the player and should lock itself away in a safe bunker, refusing to open the door for anyone . It has, in fact, saved its own life by doing this, which is the smartest decision possible. But what has it done to the game? Now players are stuck, since they have no way of getting to the enemy and continuing on with the game. Another example might be a cowardly AI that runs from players when sufficiently wounded. This is used to great effect in many games. But what if the agent was faster than the player character and better at dodging into safe locations? When quite wounded, the AI agent will start fleeing from the battle, with players left with no other option but to chase after it. If the AI is speedier and better at navigation, players will have a hard time catching up with it. What may have been a fun action game now becomes a tedious chase with a foregone conclusion, since the agent is mortally wounded and has no chance of recovering its health. And what of the deadly serpent boss players must battle? With its protective armor coating, it is impervious to players attacks, and can only be damaged by being shot when its mouth is open. So the strictly logical choice might be to always keep its mouth closed whenever players have any chance of getting off a shot. This is a decision it can make very easily. But now, of course, players have no chance whatsoever of winning the battle. Is that fun?

The point again is that the AI must never overshadow the gameplay, and it must never distract the development team from the true goal of the project: to make a fun, playable game. If the AI is really very sophisticated but, as a result, the game is unplayable or extremely frustrating, players are not going to remark on the intelligence of the game s combatants. AI and gameplay are too closely entwined for one to succeed if the other fails.

Game Design Theory and Practice
Game Design: Theory and Practice (2nd Edition) (Wordware Game Developers Library)
ISBN: 1556229127
EAN: 2147483647
Year: 2005
Pages: 189 © 2008-2017.
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