Module behavior

Everything related to AI behavior and behavior trees.

Behavior trees are simple but very powerful mechanism to implement artificial intelligence for games. The main concept is in its name. Tree is a set of connected nodes, where each node could have single parent and zero or more children nodes. Execution path of the tree is defined by the actions of the nodes. Behavior tree has a set of hard coded nodes as well as leaf nodes with user-defined logic. Hard coded nodes are: Sequence, Selector, Leaf. Leaf is special - it has custom method tick that can contain any logic you want.

For more info see:

• Wikipedia article
• Gamasutra

Modules

composite

Composite node is a container for children nodes. Composite node could be either Sequence or Selector. Sequence node will execute children nodes consecutively until Status::Failure is returned from any descendant node. In other words Sequence implement AND logical function. Selector node will execute children until Status::Success is returned from any descendant node. In other worlds Selector implement OR logical function.

inverter

A node, that inverts its child state (super::Status::Failure becomes super::Status::Success and vice versa, super::Status::Running remains unchanged)

leaf

Leaf is a “final” node of a behavior tree. It contains user-defined action which is able to mutate given context.

Structs

BehaviorTree

See module docs.

RootNode

Root node of the tree.

Enums

BehaviorNode

Possible variations of behavior nodes.

Status

Status of execution of behavior tree node.

Traits

Behavior

A trait for user-defined actions for behavior tree.

Functions

inverter

Creates a new inverter.

leaf

Creates a new leaf.

selector

Creates a new selector.

sequence

Creates a new sequence.