Demo: Refactoring, docstrings and tweaks

demo/demo/agents/02_agent_charger.tscn

@@ -4,7 +4,7 @@
 [ext_resource type="Texture2D" uid="uid://ce16nc0wy2s8" path="res://demo/assets/agent_charger.png" id="2_y7pic"]
 [ext_resource type="BehaviorTree" uid="uid://ylife72ym5et" path="res://demo/ai/trees/02_agent_charger.tres" id="3_nacc3"]
 
-[sub_resource type="BlackboardPlan" id="BlackboardPlan_b4r3u"]
+[sub_resource type="BlackboardPlan" id="BlackboardPlan_pmyhf"]
 var/speed/name = "speed"
 var/speed/type = 3
 var/speed/value = 400.0
@@ -12,7 +12,7 @@ var/speed/hint = 1
 var/speed/hint_string = "10,1000,10"
 var/charge_speed/name = "charge_speed"
 var/charge_speed/type = 3
-var/charge_speed/value = 800.0
+var/charge_speed/value = 1000.0
 var/charge_speed/hint = 1
 var/charge_speed/hint_string = "10,1000,10"
 
@@ -38,4 +38,4 @@ texture = ExtResource("2_y7pic")
 
 [node name="BTPlayer" type="BTPlayer" parent="." index="4"]
 behavior_tree = ExtResource("3_nacc3")
-blackboard_plan = SubResource("BlackboardPlan_b4r3u")
+blackboard_plan = SubResource("BlackboardPlan_pmyhf")

demo/demo/agents/06_agent_melee_combo.tscn

@@ -4,12 +4,17 @@
 [ext_resource type="Texture2D" uid="uid://bo0ibp7tvjbba" path="res://demo/assets/agent_combo.png" id="2_4rqld"]
 [ext_resource type="BehaviorTree" uid="uid://cpncl1db8j12f" path="res://demo/ai/trees/06_agent_melee_combo.tres" id="3_l805q"]
 
-[sub_resource type="BlackboardPlan" id="BlackboardPlan_78rmu"]
+[sub_resource type="BlackboardPlan" id="BlackboardPlan_67ric"]
 var/speed/name = "speed"
 var/speed/type = 3
 var/speed/value = 400.0
 var/speed/hint = 1
 var/speed/hint_string = "10,1000,10"
+var/charge_speed/name = "charge_speed"
+var/charge_speed/type = 3
+var/charge_speed/value = 1000.0
+var/charge_speed/hint = 0
+var/charge_speed/hint_string = ""
 
 [node name="AgentMeleeCombo" instance=ExtResource("1_dny3b")]
 
@@ -31,11 +36,9 @@ texture = ExtResource("2_4rqld")
 [node name="HandR" parent="Root/Rig/Body" index="2"]
 texture = ExtResource("2_4rqld")
 
-[node name="WeaponNinjaStar" parent="Root" index="2"]
+[node name="WeaponNinjaStar" parent="Root" index="1"]
-position = Vector2(-55, -76)
-rotation = 0.0
 scale = Vector2(0.999983, 0.999976)
 
 [node name="BTPlayer" type="BTPlayer" parent="." index="4"]
 behavior_tree = ExtResource("3_l805q")
-blackboard_plan = SubResource("BlackboardPlan_78rmu")
+blackboard_plan = SubResource("BlackboardPlan_67ric")

demo/demo/agents/scripts/agent_base.gd

@@ -10,9 +10,12 @@
 #*
 extends CharacterBody2D
 
-## Base agent script.
+## Base agent script that is shared by all agents.
 
+# Resource file to use in summon_minion() method.
 const MINION_RESOURCE := "res://demo/agents/03_agent_imp.tscn"
+
+# Projectile resource.
 const NinjaStar := preload("res://demo/agents/ninja_star/ninja_star.tscn")
 const Fireball := preload("res://demo/agents/fireball/fireball.tscn")
 
@@ -22,21 +25,21 @@ const Fireball := preload("res://demo/agents/fireball/fireball.tscn")
 @onready var collision_shape_2d: CollisionShape2D = $CollisionShape2D
 @onready var summoning_effect: GPUParticles2D = $FX/Summoned
 
-
 var _frames_since_facing_update: int = 0
 var _is_dead: bool = false
 
+
 func _ready() -> void:
 	health.damaged.connect(_damaged)
 	health.death.connect(die)
 
-
+## Update agent's facing in the velocity direction.
 func update_facing() -> void:
 	_frames_since_facing_update += 1
 	if _frames_since_facing_update > 3:
 		face_dir(velocity.x)
 
-
+## Face specified direction.
 func face_dir(dir: float) -> void:
 	if dir > 0.0 and root.scale.x < 0.0:
 		root.scale.x = 1.0;
@@ -72,6 +75,7 @@ func summon_minion(p_position: Vector2) -> void:
 	minion.play_summoning_effect()
 
 
+## Method is used when this agent is summoned from the dungeons of the castle AaaAaaAAAAAaaAAaaaaaa
 func play_summoning_effect() -> void:
 	summoning_effect.emitting = true
 
@@ -86,6 +90,7 @@ func is_good_position(p_position: Vector2) -> bool:
 	return collision.is_empty()
 
 
+## When agent is damaged...
 func _damaged(_amount: float, knockback: Vector2) -> void:
 	apply_knockback(knockback)
 	animation_player.play(&"hurt")
@@ -102,6 +107,7 @@ func _damaged(_amount: float, knockback: Vector2) -> void:
 		hsm.set_active(true)
 
 
+## Push agent in the knockback direction for the specified number of physics frames.
 func apply_knockback(knockback: Vector2, frames: int = 10) -> void:
 	if knockback.is_zero_approx():
 		return

demo/demo/agents/scripts/health.gd

@@ -12,10 +12,13 @@ class_name Health
 extends Node
 ## Tracks health and emits signal when damaged or dead.
 
-
+## Emitted when health is reduced to 0.
 signal death
+
+## Emitted when health is damaged.
 signal damaged(amount: float, knockback: Vector2)
 
+## Initial health value.
 @export var max_health: float = 10.0
 
 var _current: float
@@ -38,5 +41,6 @@ func take_damage(amount: float, knockback: Vector2) -> void:
 		damaged.emit(amount, knockback)
 
 
+## Returns current health.
 func get_current() -> float:
 	return _current

demo/demo/agents/scripts/hitbox.gd

@@ -12,10 +12,16 @@ class_name Hitbox
 extends Area2D
 ## Area that deals damage.
 
+## Damage value to apply.
 @export var damage: float = 1.0
+
+## Push back the victim.
 @export var knockback_enabled: bool = false
+
+## Desired pushback speed.
 @export var knockback_strength: float = 500.0
 
+
 func _ready() -> void:
 	area_entered.connect(_area_entered)
 

demo/demo/agents/scripts/hurtbox.gd

@@ -12,7 +12,6 @@ class_name Hurtbox
 extends Area2D
 ## Area that registers damage.
 
-
 @export var health: Health
 
 var last_attack_vector: Vector2

demo/demo/ai/tasks/arrive_pos.gd

@@ -10,11 +10,17 @@
 #*
 @tool
 extends BTAction
-## Arrive to a position, with a bias to horizontal movement.
+## ArrivePos: Arrive to a position, with a bias to horizontal movement.
-
+## Returns SUCCESS when close to the target position (see tolerance);
+## otherwise returns RUNNING.
 
+## Blackboard variable that stores the target position (Vector2)
 @export var target_position_var := "pos"
+
+## Variable that stores desired speed (float)
 @export var speed_var := "speed"
+
+## How close should the agent be to the target position to return SUCCESS.
 @export var tolerance := 50.0
 
 
@@ -30,10 +36,13 @@ func _tick(_delta: float) -> Status:
 
 	var speed: float = blackboard.get_var(speed_var, 10.0)
 	var dist: float = absf(agent.global_position.x - target_pos.x)
+	var dir: Vector2 = agent.global_position.direction_to(target_pos)
+
+	# Prefer horizontal movement:
 	var vertical_factor: float = remap(dist, 200.0, 500.0, 1.0, 0.0)
 	vertical_factor = clampf(vertical_factor, 0.0, 1.0)
-	var dir: Vector2 = agent.global_position.direction_to(target_pos)
 	dir.y *= vertical_factor
+
 	var desired_velocity: Vector2 = dir.normalized() * speed
 	agent.velocity = lerp(agent.velocity, desired_velocity, 0.2)
 	agent.move_and_slide()

demo/demo/ai/tasks/back_away.gd

@@ -13,14 +13,19 @@ extends BTAction
 ## BackAway
 ## Returns RUNNING always.
 
+## Blackboard variable that stores desired speed.
 @export var speed_var: String = "speed"
+
+## How much can we deviate from the "away" direction (in radians).
 @export var max_angle_deviation: float = 0.7
 
 var _dir: Vector2
 var _desired_velocity: Vector2
 
+
 # Called each time this task is entered.
 func _enter() -> void:
+	# Determine "away" direction and desired velocity
 	_dir = Vector2.LEFT * agent.get_facing()
 	var speed: float = blackboard.get_var(speed_var, 200.0)
 	var rand_angle = randf_range(-max_angle_deviation, max_angle_deviation)

demo/demo/ai/tasks/face_target.gd

@@ -10,8 +10,10 @@
 #*
 @tool
 extends BTAction
-## FaceTarget
+## FaceTarget and return SUCCESS.
+## Returns FAILURE if target is not a valid Node2D instance.
 
+## Blackboard variable that stores our target (expecting Node2D).
 @export var target_var: String = "target"
 
 # Display a customized name (requires @tool).

demo/demo/ai/tasks/get_first_in_group.gd

@@ -10,10 +10,13 @@
 #*
 @tool
 extends BTAction
-
 ## Get first node in group and save it to the blackboard.
+## Returns FAILURE if group contains 0 nodes.
 
+## Name of the SceneTree group.
 @export var group: StringName
+
+## Blackboard variable in which the task will store the acquired node.
 @export var output_var: String = "target"
 
 
@@ -24,6 +27,8 @@ func _generate_name() -> String:
 		]
 
 func _tick(_delta: float) -> Status:
-	var node = agent.get_tree().get_first_node_in_group(group)
+	var nodes: Array[Node] = agent.get_tree().get_nodes_in_group(group)
-	blackboard.set_var(output_var, node)
+	if nodes.size() == 0:
+		return FAILURE
+	blackboard.set_var(output_var, nodes[0])
 	return SUCCESS

demo/demo/ai/tasks/in_range.gd

@@ -16,8 +16,13 @@ extends BTCondition
 ## Returns SUCCESS if the agent is within the defined range;
 ## otherwise, returns FAILURE.
 
+## Minimum distance to target.
 @export var distance_min: float
+
+## Maximum distance to target.
 @export var distance_max: float
+
+## Blackboard variable that holds the target (expecting Node2D).
 @export var target_var := "target"
 
 var _min_distance_squared: float
@@ -32,6 +37,7 @@ func _generate_name() -> String:
 
 # Called to initialize the task.
 func _setup() -> void:
+	## Small performace optimization
 	_min_distance_squared = distance_min * distance_min
 	_max_distance_squared = distance_max * distance_max
 

demo/demo/ai/tasks/move_forward.gd

@@ -1,5 +1,5 @@
 #*
-#* leap_forward.gd
+#* move_forward.gd
 #* =============================================================================
 #* Copyright 2021-2024 Serhii Snitsaruk
 #*
@@ -10,22 +10,27 @@
 #*
 @tool
 extends BTAction
-## LeapForward: Applies force each tick until duration is exceeded.
+## MoveForward: Applies velocity each tick until duration is exceeded.
 ## Returns SUCCESS if elapsed time exceeded duration.
 ## Returns RUNNING if elapsed time didn't exceed duration.
 
+## Blackboard variable that stores desired speed.
+@export var speed_var: String = "speed"
 
-@export var force: float = 1000.0
+## How long to perform this task (in seconds).
 @export var duration: float = 0.1
 
 # Display a customized name (requires @tool).
 func _generate_name() -> String:
-	return "LeapForward force: " + str(force)
+	return "MoveForward  speed: %s  duration: %ss" % [
+		LimboUtility.decorate_var(speed_var),
+		duration]
 
 # Called each time this task is ticked (aka executed).
 func _tick(_delta: float) -> Status:
 	var facing: float = agent.get_facing()
-	var desired_velocity: Vector2 = Vector2.RIGHT * facing * force
+	var speed: float = blackboard.get_var(speed_var, 100.0)
+	var desired_velocity: Vector2 = Vector2.RIGHT * facing * speed
 	agent.velocity = lerp(agent.velocity, desired_velocity, 0.2)
 	agent.move_and_slide()
 	agent.update_facing()

demo/demo/ai/tasks/pursue.gd

@@ -16,24 +16,32 @@ extends BTAction
 ## Returns SUCCESS, when at the desired position from target (flanking it).
 ## Returns FAILURE, if target is not a valid Node2D instance.
 
-
+## How close should the agent be to the desired position to return SUCCESS.
 const TOLERANCE := 30.0
 
+## Blackboard variable that stores our target (expecting Node2D).
 @export var target_var: String = "target"
+
+## Blackboard variable that stores desired speed.
 @export var speed_var: String = "speed"
+
+## Desired distance from target.
 @export var approach_distance: float = 100.0
 
-#var _side: float
 var _waypoint: Vector2
 
+
 # Display a customized name (requires @tool).
 func _generate_name() -> String:
 	return "Pursue %s" % [LimboUtility.decorate_var(target_var)]
 
 
+# Called each time this task is entered.
 func _enter() -> void:
 	var target: Node2D = blackboard.get_var(target_var, null)
 	if is_instance_valid(target):
+		# Movement is performed in smaller steps.
+		# For each step, we select a new waypoint.
 		_select_new_waypoint(_get_desired_position(target))
 
 
@@ -47,9 +55,10 @@ func _tick(_delta: float) -> Status:
 	if agent.global_position.distance_to(desired_pos) < TOLERANCE:
 		return SUCCESS
 
-	var speed: float = blackboard.get_var(speed_var, 200.0)
 	if agent.global_position.distance_to(_waypoint) < TOLERANCE:
 		_select_new_waypoint(desired_pos)
+
+	var speed: float = blackboard.get_var(speed_var, 200.0)
 	var desired_velocity: Vector2 = agent.global_position.direction_to(_waypoint) * speed
 	agent.velocity = lerp(agent.velocity, desired_velocity, 0.2)
 	agent.move_and_slide()
@@ -57,7 +66,7 @@ func _tick(_delta: float) -> Status:
 	return RUNNING
 
 
-## Get closest flanking position to target.
+## Get the closest flanking position to target.
 func _get_desired_position(target: Node2D) -> Vector2:
 	var side: float = signf(agent.global_position.x - target.global_position.x)
 	var desired_pos: Vector2 = target.global_position

demo/demo/ai/tasks/select_flanking_pos.gd

@@ -23,9 +23,7 @@ enum AgentSide {
 ## Blackboard variable that holds current target (should be a Node2D instance).
 @export var target_var: String = "target"
 
-## Should closest side be selected?
+## Which agent's side should we flank?
-@export var closest_side: bool = false
-
 @export var flank_side: AgentSide = AgentSide.CLOSEST
 
 ## Minimum range relative to the target.
@@ -37,6 +35,7 @@ enum AgentSide {
 ## Blackboard variable that will be used to store selected position.
 @export var position_var: String = "pos"
 
+
 # Display a customized name (requires @tool).
 func _generate_name() -> String:
 	return "SelectFlankingPos  target: %s  range: [%s, %s]  side: %s  ➜%s" % [
@@ -46,17 +45,18 @@ func _generate_name() -> String:
 		AgentSide.keys()[flank_side],
 		LimboUtility.decorate_var(position_var)]
 
+
 # Called each time this task is ticked (aka executed).
 func _tick(_delta: float) -> Status:
 	var target := blackboard.get_var(target_var) as Node2D
 	if not is_instance_valid(target):
 		return FAILURE
 
-	var dir: float
+	var dir: float  # 1.0 is right, -1.0 is left (relative to target)
 	match flank_side:
 		AgentSide.FARTHEST:
 			dir = signf(target.global_position.x - agent.global_position.x)
-		AgentSide.CLOSEST:
+		AgentSide.CLOSEST :
 			dir = -signf(target.global_position.x - agent.global_position.x)
 		AgentSide.BACK:
 			dir = -target.get_facing()

demo/demo/ai/tasks/select_random_nearby_pos.gd

@@ -3,23 +3,29 @@ extends BTAction
 ## SelectRandomNearbyPos: Select a position nearby within specified range.
 ## Returns SUCCESS.
 
-## Maximum distance to the desired position.
+## Minimum distance to the desired position.
 @export var range_min: float = 300.0
+
+## Maximum distance to the desired position.
 @export var range_max: float = 500.0
+
+## Blackboard variable that will be used to store the desired position.
 @export var position_var: String = "pos"
 
+
 # Display a customized name (requires @tool).
 func _generate_name() -> String:
 	return "SelectRandomNearbyPos  range: [%s, %s]  ➜%s" % [
 		range_min, range_max,
 		LimboUtility.decorate_var(position_var)]
 
+
 # Called each time this task is ticked (aka executed).
 func _tick(_delta: float) -> Status:
 	var pos: Vector2
 	var is_good_position: bool = false
 	while not is_good_position:
-		# Randomize until we find a good position (in other words, not outside the arena)
+		# Randomize until we find a good position (good position == not outside the arena).
 		var angle: float = randf() * TAU
 		var rand_distance: float = randf_range(range_min, range_max)
 		pos = agent.global_position + Vector2(sin(angle), cos(angle)) * rand_distance

demo/demo/ai/trees/02_agent_charger.tres

@@ -4,7 +4,7 @@
 [ext_resource type="Script" path="res://demo/ai/tasks/select_flanking_pos.gd" id="2_t3udh"]
 [ext_resource type="Script" path="res://demo/ai/tasks/arrive_pos.gd" id="3_u2ra5"]
 [ext_resource type="Script" path="res://demo/ai/tasks/face_target.gd" id="4_xwjl7"]
-[ext_resource type="Script" path="res://demo/ai/tasks/leap_forward.gd" id="5_f6dg8"]
+[ext_resource type="Script" path="res://demo/ai/tasks/move_forward.gd" id="5_ucvak"]
 
 [sub_resource type="BlackboardPlan" id="BlackboardPlan_qd806"]
 var/speed/name = "speed"
@@ -14,7 +14,7 @@ var/speed/hint = 1
 var/speed/hint_string = "10,1000,10"
 var/charge_speed/name = "charge_speed"
 var/charge_speed/type = 3
-var/charge_speed/value = 800.0
+var/charge_speed/value = 1000.0
 var/charge_speed/hint = 1
 var/charge_speed/hint_string = "10,1000,10"
 
@@ -43,7 +43,6 @@ output_var = "target"
 [sub_resource type="BTAction" id="BTAction_pmvd0"]
 script = ExtResource("2_t3udh")
 target_var = "target"
-closest_side = false
 flank_side = 0
 range_min = 500
 range_max = 600
@@ -98,8 +97,8 @@ animation_name = &"charge"
 blend = 0.05
 
 [sub_resource type="BTAction" id="BTAction_o18uk"]
-script = ExtResource("5_f6dg8")
+script = ExtResource("5_ucvak")
-force = 1000.0
+speed_var = "charge_speed"
 duration = 2.0
 
 [sub_resource type="BTSequence" id="BTSequence_8lur1"]

demo/demo/ai/trees/06_agent_melee_combo.tres

@@ -4,7 +4,7 @@
 [ext_resource type="Script" path="res://demo/ai/tasks/select_flanking_pos.gd" id="2_5nwkp"]
 [ext_resource type="Script" path="res://demo/ai/tasks/arrive_pos.gd" id="3_3tom2"]
 [ext_resource type="Script" path="res://demo/ai/tasks/face_target.gd" id="4_hi228"]
-[ext_resource type="Script" path="res://demo/ai/tasks/leap_forward.gd" id="5_fpbac"]
+[ext_resource type="Script" path="res://demo/ai/tasks/move_forward.gd" id="5_au5yc"]
 
 [sub_resource type="BlackboardPlan" id="BlackboardPlan_46tbn"]
 var/speed/name = "speed"
@@ -12,6 +12,11 @@ var/speed/type = 3
 var/speed/value = 400.0
 var/speed/hint = 1
 var/speed/hint_string = "10,1000,10"
+var/charge_speed/name = "charge_speed"
+var/charge_speed/type = 3
+var/charge_speed/value = 1000.0
+var/charge_speed/hint = 0
+var/charge_speed/hint_string = ""
 
 [sub_resource type="BBNode" id="BBNode_nrd4b"]
 saved_value = NodePath("AnimationPlayer")
@@ -38,7 +43,6 @@ children = [SubResource("BTPlayAnimation_qiw21"), SubResource("BTRandomWait_xlud
 [sub_resource type="BTAction" id="BTAction_85keo"]
 script = ExtResource("2_5nwkp")
 target_var = "target"
-closest_side = true
 flank_side = 0
 range_min = 300
 range_max = 400
@@ -83,8 +87,8 @@ animation_player = SubResource("BBNode_s8evu")
 animation_name = &"attack_1"
 
 [sub_resource type="BTAction" id="BTAction_u22bc"]
-script = ExtResource("5_fpbac")
+script = ExtResource("5_au5yc")
-force = 1000.0
+speed_var = "charge_speed"
 duration = 0.1
 
 [sub_resource type="BTParallel" id="BTParallel_ec2e3"]
@@ -104,8 +108,8 @@ animation_player = SubResource("BBNode_3oljv")
 animation_name = &"attack_2"
 
 [sub_resource type="BTAction" id="BTAction_yuxl3"]
-script = ExtResource("5_fpbac")
+script = ExtResource("5_au5yc")
-force = 1000.0
+speed_var = "charge_speed"
 duration = 0.1
 
 [sub_resource type="BTParallel" id="BTParallel_thojy"]
@@ -125,8 +129,8 @@ animation_player = SubResource("BBNode_ot40l")
 animation_name = &"attack_3"
 
 [sub_resource type="BTAction" id="BTAction_rwp18"]
-script = ExtResource("5_fpbac")
+script = ExtResource("5_au5yc")
-force = 1000.0
+speed_var = "charge_speed"
 duration = 0.1
 
 [sub_resource type="BTParallel" id="BTParallel_qmdfb"]

demo/demo/props/dummy.gd

@@ -4,10 +4,12 @@ extends CharacterBody2D
 @onready var hurtbox: Hurtbox = $Hurtbox
 @onready var root: Node2D = $Root
 
+
 func _on_health_damaged(_amount: float, _knockback: Vector2) -> void:
 	root.scale.x = -signf(hurtbox.last_attack_vector.x)
 	animation_player.clear_queue()
 	animation_player.play(&"hurt", 0.1)
 
+
 func get_facing() -> float:
 	return signf(root.scale.x)

demo/demo/scenes/agent_showcase.gd

@@ -77,4 +77,4 @@ func _on_agent_selection_id_pressed(id: int) -> void:
 	_load_agent("res://demo/agents/".path_join(agent_files[id]))
 	agent_selection.text = bt_player.behavior_tree.resource_path.get_file()
 	previous.disabled = id == 0
-	next.disabled = id == 8
+	next.disabled = id == (agent_files.size()-1)