Fix #35 : behavior trees and blackboard can be reset

Author: Earewien

README.md

@@ -45,6 +45,8 @@ Data in blackboard can be isolated in so-called *namespaces*. A data key can exi
 Some well-known properties are already fed by the root tree during execution :
 - `delta` : the float value of delta from *process* or *physics process* (depending on root tree process mode).
 
+A blackboard can also be reset using `reset` method. This method will erase all blackboard content, except well-known properties. The initial data is also restored after resetting the blackboard.
+
 ![image](documentation/assets/nodes/btblackboard.png)
 
 🔑 Properties list:
@@ -63,6 +65,8 @@ Its the entry point of your behavior tree. It can only have a unique child of ty
 - `blackboard` : path to the blackboard node. This allows to share a same blackboard between several trees, for example to code a group of enemies acting together, or to specify some default entries using the editor. If empty, a default empty blackboard will be used during tree execution. Default is *empty*,
 - `enable_monitor` (*debug option*) : indicates if, in debug mode, a custom monitor should be created for this tree. Custom monitor allows to track performances in Debugger Monitors view.
 
+`BTRoot` can be reset, allowinf to resuse the node for another usage. Resetting the tree ensures that all its nodes will be reset too (recursively). Resetting the tree does *not* reset the associated blackboard, since blackboards can be shared among multiple trees. To reset the blackboard, use its reset function.
+
 ###  ![icon](addons/yet_another_behavior_tree/src/Assets/Icons/btselector.png) BTSelector
 
 The selector node is a *composite node* that executes its children from the first one to the last one, in order, until one of them returns *SUCCESS*. If a selector child succeeds, the selector succeed too. If all selector children failed, the selector fails too.

addons/yet_another_behavior_tree/src/Blackboard/BTBlackboard.gd

@@ -50,8 +50,7 @@ var _default_namespace_data:Dictionary
 
 func _ready() -> void:
     # On copie le dico défini par l'utilisateur dans le dico privé
-    _default_namespace_data = _get_namespace_board(DEFAULT_NAMESPACE)
-    _default_namespace_data.merge(data)
+    _init_default_namespace()
 
 #------------------------------------------
 # Fonctions publiques
@@ -81,10 +80,24 @@ func delete_data(key:Variant, board_namespace:String = DEFAULT_NAMESPACE) -> Var
     namespace_dico.erase(key)
     return old_value.get_ref() if old_value is WeakRef else old_value
 
+## Reset the whole blackboard, erasing all data from it.
+## Data set in node configuration through [data] field is restored
+func reset() -> void:
+    # To prevent tree from just stop working, we preserve delta value into the blackboard
+    # It's an internal state, shoumd never be erased by user
+    var delta:float = get_delta()
+    _execution_data.clear()
+    _init_default_namespace()
+    _unsafe_set_delta(delta)
+
 #------------------------------------------
 # Fonctions privées
 #------------------------------------------
 
+func _init_default_namespace() -> void:
+    _default_namespace_data = _get_namespace_board(DEFAULT_NAMESPACE)
+    _default_namespace_data.merge(data)
+
 func _get_namespace_board(board_namespace:String) -> Dictionary:
     if not _execution_data.has(board_namespace):
         _execution_data[board_namespace] = {}

addons/yet_another_behavior_tree/src/Nodes/BTNode.gd

@@ -69,6 +69,10 @@ func stop(blackboard:BTBlackboard) -> void:
 func exit(blackboard:BTBlackboard) -> void:
     pass
 
+## Reset node state, as it is was just instantiated
+func reset() -> void:
+    pass
+
 #------------------------------------------
 # Fonctions privées
 #------------------------------------------

addons/yet_another_behavior_tree/src/Nodes/BTRoot.gd

@@ -127,6 +127,14 @@ func _get_configuration_warnings() -> PackedStringArray:
 # Fonctions publiques
 #------------------------------------------
 
+## Reset behavior tree state, and children states too
+## This method should never be called when tree is used. It is intended to recycle the
+## tree for other usage, so it should be called outside tree execution
+## Tree associated blackboard is NOT reset. To do it, call reset function on blackboard itself.
+func reset() -> void:
+    _internal_state.clear()
+    _children[0].reset()
+
 #------------------------------------------
 # Fonctions privées
 #------------------------------------------

addons/yet_another_behavior_tree/src/Nodes/Composite/BTComposite.gd

@@ -42,6 +42,10 @@ func _get_configuration_warnings() -> PackedStringArray:
 # Fonctions publiques
 #------------------------------------------
 
+func reset() -> void:
+    for child in _children:
+        child.reset()
+
 #------------------------------------------
 # Fonctions privées
 #------------------------------------------

addons/yet_another_behavior_tree/src/Nodes/Composite/BTSelector.gd

@@ -53,6 +53,10 @@ func tick(actor:Node, blackboard:BTBlackboard) -> int:
 # Fonctions publiques
 #------------------------------------------
 
+func reset() -> void:
+    _running_child_index = -1
+    super.reset()
+
 #------------------------------------------
 # Fonctions privées
 #------------------------------------------

addons/yet_another_behavior_tree/src/Nodes/Composite/BTSequence.gd

@@ -53,6 +53,10 @@ func tick(actor:Node, blackboard:BTBlackboard) -> int:
 # Fonctions publiques
 #------------------------------------------
 
+func reset() -> void:
+    _running_child_index = -1
+    super.reset()
+
 #------------------------------------------
 # Fonctions privées
 #------------------------------------------

addons/yet_another_behavior_tree/src/Nodes/Decorators/BTDecorator.gd

@@ -41,6 +41,10 @@ func _get_configuration_warnings() -> PackedStringArray:
 # Fonctions publiques
 #------------------------------------------
 
+func reset() -> void:
+    for child in _children:
+        child.reset()
+
 #------------------------------------------
 # Fonctions privées
 #------------------------------------------

addons/yet_another_behavior_tree/src/Nodes/Decorators/BTLimiter.gd

@@ -55,6 +55,10 @@ func tick(actor:Node, blackboard:BTBlackboard) -> int:
         _invocation_count += 1
     return result
 
+func reset() -> void:
+    _invocation_count = 0
+    super.reset()
+
 #------------------------------------------
 # Fonctions privées
 #------------------------------------------

addons/yet_another_behavior_tree/src/Nodes/Leaves/BTActionWait.gd

@@ -55,6 +55,10 @@ func start(blackboard:BTBlackboard) -> void:
     if random_deviation_ms != 0:
         _time_to_reach_ms += randi_range(0, random_deviation_ms)
 
+func reset() -> void:
+    _current_time_ms = 0
+    _time_to_reach_ms = 0
+
 #------------------------------------------
 # Fonctions privées
 #------------------------------------------