It's been nearly a year since my first article outlining the then-current trends in the game development industry regarding game AI ("Game AI: The State of the Industry," October 1998). Since that time, another Christmas season's worth of releases has come and gone and another Game Developers Conference (GDC) has provided yet another opportunity for AI developers to exchange ideas. While polls taken at the 1999 GDC indicate that most developers (myself included) felt that the last year had seen incremental, rather than revolutionary advances in the field of game AI, it seemed that enough interesting new developments have taken place, which makes an update to my previous article seem natural.

I'm very pleased to say that good game AI is growing in importance within the industry, with both developers and marketeers seeing the value in building better and more capable computer opponents. The fears that multiplayer options on games would make good computer AIs obsolete appear to have blown over in the face of one very practical consideration — sometimes, you just don't have time to play with anybody else. The incredible pace of development in 3D graphics cards and game engines has made awesome graphics an expected feature, not an added one. Developers have found that one discriminator in a crowded marketplace is good computer AI.

As with last year's article, much of the insights presented herein flow directly from the AI roundtable discussions at the 1999 GDC. This interaction with my fellow developers has proven invaluable in the past, and the 1999 AI roundtables proved to be every bit as useful in gaining insight into what other developers are doing, the problems they're facing, and where they're going. I'll touch on some of the topics and concerns broached by developers at the 1999 roundtables. I'll also discuss what AI techniques and developments seem to be gaining favor among developers, the academic world's take on the game AI field, and where some developers think game AI will be headed in the coming year or two.

Is The Resource Battle Over?

Last year there were signs that development teams were beginning to take game AI much more seriously than they had in the past. Developers were getting involved in the design of the AI earlier in the design cycle, and many projects were beginning to dedicate one or more programmers exclusively to AI development. Polls from the AI roundtables showed a substantial increase in the number of developers devoted exclusively to AI programming (see Figure 1).

Resources dedicated to AI development.

It was very apparent at the 1999 GDC that this trend has continued at a healthy clip, with 60 percent of the attendees at my roundtables reporting that their projects included one or more dedicated AI programmers. This number is up from approximately 24 percent in 1997 and 46 percent in 1998 and shows a growing desire on the part of development houses to make AI a more important part of their game design. If the trend continues, we'll see dedicated AI developers become as routine as dedicated 3D engine or sound developers.

AI specialists continue to be a viable alternative for many companies that lack internal resources to dedicate developers exclusively to AI development. Several developers and producers present at the roundtables indicated that they had used independent contractors to roll the AI portions of their process with varying degrees of success. The primary complaints about using contract help were perhaps the universal ones — you never really know what you're getting, and maintaining good communication is, at best, a chore.

The most interesting comments, however, concerned CPU resources available to the AI developers (Figure 1). None of the developers answering the poll questions regarding CPU resources felt that they had too little CPU available. Everybody felt they could use more if they had it, but nobody said that they were having to fight tooth and nail for resources as they had in the past. This is an amazing turn of events, which is in stark contrast to previous years when AI developers complained often and bitterly of fighting the graphics engine guys for CPU cycles. The overall percentages of CPU cycles most developers felt they were getting didn't really change, but developers were feeling much less pinched than they had been in the past. When asked why this was the case, there were a variety of theories. Most developers felt that this was, quite simply, due to the fact that faster hardware is now standard on both PCs and consoles — 5 percent of a 400Mhz Pentium III is a heck of a lot more horsepower than 5 percent of a 200Mhz Pentium I. Others thought that the availability of faster 3D hardware, combined with greater expertise of the 3D engine manufacturers, had simply made 3D engines more efficient than they had been and thus freed up more CPU resources for other tasks. Whatever the reasons, everybody was happy about it, and they thought it would only get better as hardware got faster.

The one great problem mentioned by all was the impending-shipping-date-syndrome. Christmas hasn't moved from its place as an almost magical date for targeting new releases, and the increasing complexity of games in general hasn't made meeting deadlines any easier. While there are more programmers dedicated exclusively to the AI portion of game development now than there had been in the past, most developers felt that the task itself had become more difficult.

Part of the reason for this, of course, is the increasing importance of game AI itself — having made the case that good game AI is important in increasing the odds of a game's success, developers must now actually deliver better game AI. Quite simply, that takes time. When coupled with the fact that most AI testing can't really begin until substantial portions of the game's engine are up and running, you've got a situation wherein dedicated AI developers find themselves making compromises in the face of impending shipping dates.

Some developers also professed that part of the problem was the advances made in competing products. For example, after one real-time strategy (RTS) game introduced production queues, players started looking for all RTS games to do the same, and that means additional AI development for handling such things. There is also a desire on the part of most developers to avoid doing the "same old thing" in a new release.