Heuristic algorithms have been used in the arcade games. The common method of controlling an NPC in the game was by scripting.
‘Path finding’ is another common A.I. system that has been used in the real time strategy games. ‘Path finding’ works by calculating how to get an NPC from one place to another after considering the terrain and obstacles.
Games like Quake and Pursuit based all the enemy actions on particular stored patterns. The space invaders further refined this movement, by adding in-game events which were dependent on the hash functions.
This resulted in more varied and complex enemy movements.
Pac-Man incorporated this technology, at the same time jazzing it up by providing different personalities for each ghosts.
Although the ghost movements in Pac-Man felt random, it was a cleverly scripted and well disguised action.
The 1990’s saw the emergence of finite state machines. The arcade racing games were powered by a ‘rubber banding’ A.I. system.
If the computer controlled the opponents “fall behind”,
they received a superb boost allowing them to catch up.
The system too, works the other way around, enabling the human players to catch up if they fall behind. The arcade shooting games should ideally have a large rule base which is basically the list of NPC options like attack long range, call for help, flee etc.
The trick lies in using a random factor to choose from this base factor. This has displayed an enhanced feeling of intellect and developed the fun factor.