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Behavior Tree Implementation Techniques: Top-Down Polling vs. Bottom-Up Events

Phil Carlisle on September 27, 2008

In this 2h30 session, Phil Carlisle and Alex Champandard discuss the programming details behind behavior trees, and hierarchical logic in general. Two major approaches are covered: the first implementation relies on modular behaviors that get updated regularly in a polling fashion. Here, all the control flow and memory management is distributed. The second approach is rather more centralized with a scheduler responsible for executing behaviors, and a blackboard that stores the task memories. The relative merits of each solution is discussed and analyzed.