Added a StateMachine interface

src/StateMachines/StateMachine.gd

@@ -1,18 +1,39 @@
- extends Node
- class_name StateMachine
+extends Node
+class_name StateMachine
 
- var state = null
- var previous_state = null
+var state = null setget set_state
+var previous_state = null
+var states = {}
 
- onready var parent = get_parent()
+onready var parent = get_parent()
 
- func _state_logic(delta):
+func _physics_process(delta):
+	if state != null:
+		_state_logic(delta)
+		var transition = _get_transition(delta)
+		if transition != null:
+			set_state(transition)
+
+func _state_logic(_delta):
 	pass
 
- func _get_transition(delta):
+func _get_transition(_delta):
 	return null
 
- func _enter_state(new_state, old_state):
+func _enter_state(_new_state, _previous_state):
 	pass
 
- func _exit_state
+func _exit_state(_previous_state, _new_state):
+	pass
+
+func set_state(new_state):
+	previous_state = state
+	state = new_state
+
+	if previous_state != null:
+		_exit_state(previous_state, new_state)
+	if new_state != null:
+		_enter_state(new_state, previous_state)
+
+func add_state(state_name):
+	states[states.size()] = state_name