Added demo for behavior tree

project/main-scenes/island.tscn

@@ -1,4 +1,4 @@
-[gd_scene load_steps=8 format=4 uid="uid://b88asko1ugyd2"]
+[gd_scene load_steps=10 format=4 uid="uid://b88asko1ugyd2"]
 
 [ext_resource type="Script" path="res://scripts/global/GameManager.gd" id="1_eeg2d"]
 [ext_resource type="Script" path="res://scripts/tilemap/World.gd" id="1_k0rw8"]
@@ -7,6 +7,8 @@
 [ext_resource type="Script" path="res://scripts/player/PlayerManager.gd" id="4_1xqo1"]
 [ext_resource type="Script" path="res://scripts/player/tree/BehaviorTree.gd" id="6_efs30"]
 [ext_resource type="Script" path="res://scripts/player/tree/impl/base/TaskSelector.gd" id="7_1jajd"]
+[ext_resource type="Script" path="res://scripts/player/tree/impl/context/Task5050Success.gd" id="8_xrswf"]
+[ext_resource type="Script" path="res://scripts/player/tree/impl/context/Task5050Running.gd" id="9_r13cd"]
 
 [node name="Island-scene" type="Node2D"]
 script = ExtResource("1_eeg2d")
@@ -41,3 +43,9 @@ script = ExtResource("6_efs30")
 
 [node name="sl_Root" type="Node" parent="PlayerManager/BehaviorTree"]
 script = ExtResource("7_1jajd")
+
+[node name="5050Success" type="Node" parent="PlayerManager/BehaviorTree/sl_Root"]
+script = ExtResource("8_xrswf")
+
+[node name="5050Running" type="Node" parent="PlayerManager/BehaviorTree/sl_Root"]
+script = ExtResource("9_r13cd")

project/scripts/player/tree/BehaviorTree.gd

@@ -25,5 +25,7 @@ func populate_blackboard():
 
 
 func game_tick() -> void:
+    print("game_tick:")
     populate_blackboard()
     behavior_tree.internal_run(blackboard)
+    print(" ==> [active state=", blackboard["current_task"], "] [status=", behavior_tree.status, "]")

project/scripts/player/tree/Task.gd

@@ -5,19 +5,40 @@ enum {FAILURE = -1, SUCCESS = 1, RUNNING = 0}
 var status: int = FAILURE
 
 
+func _ready() -> void:
+    for c in get_children():
+        if not c is Task:
+            push_error("Child is not a task: " + c.name + " in " + name)
+            return
+
+
 func internal_run(p_blackboard: Dictionary) -> void:
     p_blackboard["current_task"] = self
 
     if status == RUNNING:
-        for c in self.get_children():
-            if not c.status == RUNNING:
-                continue
-            c.internal_run(p_blackboard)
-            if c.status != SUCCESS:
-                status = c.status
+        var running_child: Task = find_running_child()
+        if running_child != null:
+            running_child.internal_run(p_blackboard)
+            status = running_child.status
             return
-
+        else:
             run(p_blackboard)
+    else:
+        run(p_blackboard)
+    print(" - ", name, " ", status)
+
+
+func find_running_child() -> Task:
+    for c in get_children():
+        if c.status == RUNNING:
+            return c
+    return null
+
+
+func run_child(p_blackboard: Dictionary, p_child: Task) -> void:
+    p_child.internal_run(p_blackboard)
+    if p_child.status != RUNNING:
+        status = RUNNING
 
 
 func run(p_blackboard: Dictionary) -> void:

project/scripts/player/tree/impl/base/TaskSelector.gd

@@ -3,7 +3,7 @@ extends Task
 
 func run(blackboard: Dictionary) -> void:
     for c in self.get_children():
-        c.internal_run(blackboard)
+        run_child(blackboard, c)
         if c.status != FAILURE:
             status = c.status
             return

project/scripts/player/tree/impl/base/TaskSequence.gd

@@ -3,7 +3,7 @@ extends Task
 
 func run(blackboard: Dictionary) -> void:
     for c in self.get_children():
-        c.internal_run(blackboard)
+        run_child(blackboard, c)
         if c.status != SUCCESS:
             status = c.status
             return

project/scripts/player/tree/impl/context/Task5050Running.gd

@@ -0,0 +1,9 @@
+class_name Task5050Running
+extends Task
+
+func run(blackboard: Dictionary) -> void:
+    var random: int = randi() % 2
+    if random == 0:
+        status = RUNNING
+    else:
+        status = SUCCESS

project/scripts/player/tree/impl/context/Task5050Success.gd

@@ -0,0 +1,9 @@
+class_name Task5050Success
+extends Task
+
+func run(blackboard: Dictionary) -> void:
+    var random: int = randi() % 2
+    if random == 0:
+        status = SUCCESS
+    else:
+        status = FAILURE