LimboHSM

Event-based Hierarchical State Machine (HSM).

Description

Event-based Hierarchical State Machine (HSM) that manages LimboState instances and facilitates transitions between them. LimboHSM is a LimboState in itself and can also serve as a child of another LimboHSM node.

Properties

LimboState	ANYSTATE
LimboState	initial_state
UpdateMode	update_mode	`1`

Methods

void	add_transition(from_state: LimboState, to_state: LimboState, event: `StringName`, guard: `Callable` = Callable())
void	change_active_state(state: LimboState)
LimboState	get_active_state() const
LimboState	get_leaf_state() const
LimboState	get_previous_active_state() const
`bool`	has_transition(from_state: LimboState, event: `StringName`) const
void	initialize(agent: `Node`, parent_scope: Blackboard = null)
void	remove_transition(from_state: LimboState, event: `StringName`)
void	set_active(active: `bool`)
void	update(delta: `float`)

Signals

active_state_changed(current: LimboState, previous: LimboState) 🔗

Emitted when the currently active substate is switched to a different substate.

Enumerations

enum UpdateMode: 🔗

UpdateMode IDLE = 0

Update the state machine during the idle process.

UpdateMode PHYSICS = 1

Update the state machine during the physics process.

UpdateMode MANUAL = 2

Manually update the state machine by calling update from a script.

Property Descriptions

LimboState ANYSTATE 🔗

LimboState anystate()

Useful for defining a transition from any state.

LimboState initial_state 🔗

void set_initial_state(value: LimboState)
LimboState get_initial_state()

The substate that becomes active when the state machine is activated using the set_active method. If not explicitly set, the first child of the LimboHSM will be considered the initial state.

UpdateMode update_mode = 1 🔗

void set_update_mode(value: UpdateMode)
UpdateMode get_update_mode()

Specifies when the state machine should be updated. See UpdateMode.

Method Descriptions

void add_transition(from_state: LimboState, to_state: LimboState, event: StringName, guard: Callable = Callable()) 🔗

Establishes a transition from one state to another when event is dispatched. Both from_state and to_state must be immediate children of this LimboHSM.

Optionally, a guard function can be specified, which must return a boolean value. If the guard function returns false, the transition will not occur. The guard function is called immediately before the transition is considered. For a state-wide guard function, check out LimboState.set_guard.

func my_guard() -> bool:
    return is_some_condition_met()

void change_active_state(state: LimboState) 🔗

Changes the currently active substate to state. If state is already active, it will be exited and reentered.

state must be a child of this LimboHSM.

LimboState get_active_state() const 🔗

Returns the currently active substate.

LimboState get_leaf_state() const 🔗

Returns the currently active leaf state within the state machine.

LimboState get_previous_active_state() const 🔗

Returns the previously active substate.

bool has_transition(from_state: LimboState, event: StringName) const 🔗

Returns true if there is a transition from from_state for a given event.

void initialize(agent: Node, parent_scope: Blackboard = null) 🔗

Initiates the state and calls LimboState._setup for both itself and all substates.

void remove_transition(from_state: LimboState, event: StringName) 🔗

Removes a transition from a state associated with specific event.

void set_active(active: bool) 🔗

When set to true, switches the state to initial_state and activates state processing according to update_mode.

void update(delta: float) 🔗

Calls LimboState._update on itself and the active substate, with the call cascading down to the leaf state. This method is automatically triggered if update_mode is not set to MANUAL.