The Design And Implementation Of Game Characters Control System Based On Behavior Tree

Due to the rapid growth of gaming industry, more and more game companies begin to develop their own games. The programmers spend lots of time developing the complex control logic module of game characters while the game designers can hardly participate in the game development. The reason is that most games use finite-state machine solution to control the logic of their game characters, so this paper analyzes the advantages and disadvantades of using finite-state machine in game industry, and in order to lift the efficiency of game development up, translate the work of game characters controlling development from programmers to game designers, this paper presents a solution based on behavior tree, then designs and implements the system.Using Windows Presentation Foundation along with the data binding technology, the system provides user with a visual behavior three editor so that game designers can edit the logic of game characters visually with the editor. The system defines a set of rules to describe a behavior tree using XML, and provides a responding XML parsing library. Meanwhile, the main part of the system is the behavior tree library, which is developed by C# using blackboard technology, and driven by the event system which is also built by this system. The library provides user with some basic components like data structure of behavior tree, runtime environment, behavior tree service and so on, and it is able to parse and execute th e behavior tree described by XML correctly. Last but not least, the solution encapsulate the behavior tree library in a framework so that game programmers can easily integrate this solution into their own game development.This paper describes the implementation of the system in detail. And the system has been used in one large client game developed by Tencent. It turns out to be a nice result by using this system, because it can apply the control logic, which is configured by game designers in the behavior tree editor, correctly to game characters, and meanwhile effectively reduce the burden on the programmers and increases the participation of game designers during game developing. That means the system improve the efficiency of game development. At Last, this paper develops a small game DEMO to test the system, and the result is that this system has good performance, all features are correct.