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SubTree

The SubTree node lets you reference a standalone behavior tree as a node inside another tree, so you can split up and reuse complex logic.

During loading, a node whose category is "tree" is instantiated as a SubTree (see Load in core/BehaviorTree.go).

Prerequisite​

SubTrees require the dedicated editor branch behavior3editor, which exports nodes with a category field.

How it works​

  • A SubTree node in the parent tree points to a child tree's ID.
  • When the tick reaches the SubTree, it enters the corresponding child tree, runs it, and returns the result to the parent.
  • Memory-node state of each child tree is likewise stored in the blackboard.

Known issue​

Q: Is the blackboard data of identical memory nodes in a subtree duplicated?

A: It is a known issue, but because the next entry resets the node's blackboard data in OnOpen, it does not manifest as an error. If you hit a real bug, please report it.

Examples​

The repository includes subtree-related examples:

  • examples/subtree — subtree usage (requires the dedicated editor branch).
  • examples/memsubtree — memory subtree example.

See Examples.