BehaviorTree
Inherits:
Contains Behavior Tree data.
Description
Behavior Trees are hierarchical structures used to model and control the behavior of agents in a game (e.g., characters, enemies, entities). They are designed to make it easier to create complex and highly modular behaviors for your games.
Behavior Trees are composed of tasks that represent specific actions or decision-making rules. Tasks can be broadly categorized into two main types: control tasks and leaf tasks. Control tasks determine the execution flow within the tree. They include BTSequence, BTSelector, and BTInvert. Leaf tasks represent specific actions to perform, like moving or attacking, or conditions that need to be checked. The BTTask class provides the foundation for various building blocks of the Behavior Trees. BT tasks can share data with the help of Blackboard. See BTTask.blackboard and Blackboard.
Note: To create your own actions, extend the BTAction class.
The BehaviorTree is executed from the root task and follows the rules specified by the control tasks, all the way down to the leaf tasks, which represent the actual actions that the agent should perform or conditions that should be checked. Each task returns a status when it is executed. It can be SUCCESS, RUNNING, or FAILURE. These statuses determine how the tree progresses. They are defined in Status.
Behavior Trees handle conditional logic using condition tasks. These tasks check for specific conditions and return either SUCCESS or FAILURE based on the state of the agent or its environment (e.g., “IsLowOnHealth”, “IsTargetInSight”). Conditions can be used together with BTSequence and BTSelector to craft your decision-making logic.
Note: To create your own conditions, extend the BTCondition class.
Check out the BTTask class, which provides the foundation for various building blocks of Behavior Trees.
Properties
String |
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Methods
clone ( ) const |
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void |
copy_other ( BehaviorTree other ) |
get_root_task ( ) const |
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instantiate ( Node agent, Blackboard blackboard, Node scene_root ) const |
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void |
set_root_task ( BTTask task ) |
Signals
plan_changed ( )
Emitted when the BlackboardPlan changes.
Property Descriptions
BlackboardPlan blackboard_plan
void set_blackboard_plan ( BlackboardPlan value )
BlackboardPlan get_blackboard_plan ( )
Stores and manages variables that will be used in constructing new Blackboard instances.
String description = ""
void set_description ( String value )
String get_description ( )
User-provided description of the BehaviorTree.
Method Descriptions
BehaviorTree clone ( ) const
Makes a copy of the BehaviorTree resource.
void copy_other ( BehaviorTree other )
Become a copy of another behavior tree.
BTTask get_root_task ( ) const
Returns the root task of the BehaviorTree resource.
BTTask instantiate ( Node agent, Blackboard blackboard, Node scene_root ) const
Instantiates the behavior tree and returns the root BTTask. scene_root should be the root node of the scene that the Behavior Tree will be used in (e.g., the owner of the node that contains the behavior tree).
void set_root_task ( BTTask task )
Assigns a new root task to the BehaviorTree resource.