ABSTRACT
This chapter looks at building robust and reusable world interfaces using two different techniques: event passing and polling. The event passing system will be extended to include simulation of sensory perception, a hot topic in generation game artificial intelligence (AI). With a special-purpose, single-game AI, there may be no dividing line between the world interface and the AI code: if the AI needs some information it can go and find it there and then. In an engine designed to support AI in multiple games, however, it is essential for stability and reusability to have a single central world interface system. The simplest implementation of polling is for each AI algorithm to request the information it needs, whenever it needs it. AI software used in the film industry and military simulation use more comprehensive models of perception to drive very sophisticated group behaviors.
