57 lines
2 KiB
GDScript
57 lines
2 KiB
GDScript
## Virtual base class for all nodes that deal directly with states.
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## Extend this class and override its methods to implement a state machine.
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class_name StateMachine extends Node
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## The initial state of the state machine. If not set, the first child node is used.
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@export var initial_state: State
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## The state machine's current loaded state
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@onready var state: State = _get_initial_state()
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func _ready() -> void:
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assert(state != null, "initial state is null")
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for state_node: State in find_children("*", "State"):
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# fixes duplicate connections (not sure why)
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if not state_node.finished.is_connected(_transition_to_next_state):
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state_node.finished.connect(_transition_to_next_state)
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await owner.ready
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state.enter("")
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func _unhandled_input(event: InputEvent) -> void:
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state.handle_input(event)
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func _process(delta: float) -> void:
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state.state_update(delta)
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func _physics_process(delta: float) -> void:
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state.state_physics_update(delta)
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## Called when initial state is not specified.
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## Returns the first child node by default.
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## Override if necessary, but don't call it directly.
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func _get_initial_state() -> State:
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return initial_state if initial_state != null else get_child(0)
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## Transitions the active state out after receiving a finished signal.
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func _transition_to_next_state(target_state_path: String, data: Dictionary[StringName, Variant] = {}) -> void:
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print(owner.name+"+++ TRANSITION CALLED: ", target_state_path)
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print(owner.name+"+++ has node? ", has_node(target_state_path))
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print(owner.name+"+++ all children: ", get_children().map(func(c: Node) -> StringName: return c.name))
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assert(has_node(target_state_path), owner.name + ": Trying to transition to state " + target_state_path + " but it does not exist.")
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if not has_node(target_state_path):
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printerr(owner.name + ": Trying to transition to state " + target_state_path + " but it does not exist.")
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return
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var previous_state_path: StringName = state.name
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state.exit()
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state = get_node(target_state_path)
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state.enter(previous_state_path, data)
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