Game AI Pro 3

12

A Reusable, Light-Weight Finite-State Machine

David “Rez” Graham

12.1    Introduction

12.2    Finite-State Machine Architecture

12.3    State Transitions

12.4    Hierarchies of State Machines and Metastates

12.5    Data-Driving the State Machine

12.6    Performance and Memory Improvements

12.7    Conclusion

References

12.1  Introduction

Finite-state machines are an architectural structure used to encapsulate the behavior of discrete states within a system and are commonly used in games for AI, animation, managing game states, and a variety of other tasks (Fu 2004).

For example, consider a guard character that can walk to different waypoints. When he or she sees the player, he or she starts shooting. The guard can be in one of the two states: ...