Demo: Implement skirmisher AI

demo/demo/agents/agent_skirmisher.tscn

@@ -1,17 +1,35 @@
-[gd_scene load_steps=3 format=3 uid="uid://co6yeafaljbq0"]
+[gd_scene load_steps=5 format=3 uid="uid://co6yeafaljbq0"]
 
 [ext_resource type="PackedScene" uid="uid://ooigbfhfy4wa" path="res://demo/agents/agent_base.tscn" id="1_2ir76"]
 [ext_resource type="Texture2D" uid="uid://l042ovqqsy3l" path="res://demo/assets/agent_skirmisher.png" id="2_w8tqw"]
+[ext_resource type="BehaviorTree" uid="uid://qqmjvbeibatn" path="res://demo/ai/trees/enemy_melee_skirmisher.tres" id="3_bhfkv"]
 
-[node name="Bobby" instance=ExtResource("1_2ir76")]
+[sub_resource type="BlackboardPlan" id="BlackboardPlan_vjbry"]
+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/fast_speed/name = "fast_speed"
+var/fast_speed/type = 3
+var/fast_speed/value = 600.0
+var/fast_speed/hint = 1
+var/fast_speed/hint_string = "10,1000,10"
+var/slow_speed/name = "slow_speed"
+var/slow_speed/type = 3
+var/slow_speed/value = 300.0
+var/slow_speed/hint = 1
+var/slow_speed/hint_string = "10,1000,10"
 
-[node name="LegL" parent="Root/Rig" index="0"]
+[node name="AgentSkirmisher" instance=ExtResource("1_2ir76")]
+
+[node name="LegL" parent="Root/Rig" index="1"]
 texture = ExtResource("2_w8tqw")
 
-[node name="LegR" parent="Root/Rig" index="1"]
+[node name="LegR" parent="Root/Rig" index="2"]
 texture = ExtResource("2_w8tqw")
 
-[node name="Body" parent="Root/Rig" index="2"]
+[node name="Body" parent="Root/Rig" index="3"]
 texture = ExtResource("2_w8tqw")
 
 [node name="Hat" parent="Root/Rig/Body" index="0"]
@@ -22,3 +40,7 @@ texture = ExtResource("2_w8tqw")
 
 [node name="HandR" parent="Root/Rig/Body" index="2"]
 texture = ExtResource("2_w8tqw")
+
+[node name="BTPlayer" type="BTPlayer" parent="." index="4"]
+behavior_tree = ExtResource("3_bhfkv")
+blackboard_plan = SubResource("BlackboardPlan_vjbry")

demo/demo/agents/player/player.tscn

@@ -12,8 +12,6 @@ collision_mask = 1
 script = ExtResource("2_24nyi")
 
 [node name="WeaponNinjaStar" parent="Root" index="2"]
-position = Vector2(-55, -76)
-rotation = 0.0
 scale = Vector2(0.999983, 0.999976)
 
 [node name="Hitbox" parent="Root" index="3"]

demo/demo/ai/tasks/arrive_pos.gd

@@ -13,7 +13,7 @@ extends BTAction
 ## Arrive to a position, with a bias to horizontal movement.
 
 
-@export var target_position_var := "target_position"
+@export var target_position_var := "pos"
 @export var speed_var := "speed"
 @export var tolerance := 50.0
 

demo/demo/ai/tasks/back_away.gd

@@ -0,0 +1,35 @@
+#*
+#* back_away.gd
+#* =============================================================================
+#* Copyright 2021-2024 Serhii Snitsaruk
+#*
+#* Use of this source code is governed by an MIT-style
+#* license that can be found in the LICENSE file or at
+#* https://opensource.org/licenses/MIT.
+#* =============================================================================
+#*
+@tool
+extends BTAction
+## BackAway
+## Returns RUNNING always.
+
+@export var speed_var: String = "speed"
+@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:
+	_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)
+	_desired_velocity = _dir.rotated(rand_angle) * speed
+
+
+# Called each time this task is ticked (aka executed).
+func _tick(_delta: float) -> Status:
+	agent.velocity = lerp(agent.velocity, _desired_velocity, 0.2)
+	agent.move_and_slide()
+	agent.face_dir(-signf(_dir.x))
+	return RUNNING

demo/demo/ai/tasks/in_range.gd

@@ -0,0 +1,49 @@
+#*
+#* in_range.gd
+#* =============================================================================
+#* Copyright 2021-2024 Serhii Snitsaruk
+#*
+#* Use of this source code is governed by an MIT-style
+#* license that can be found in the LICENSE file or at
+#* https://opensource.org/licenses/MIT.
+#* =============================================================================
+#*
+@tool
+extends BTCondition
+
+## InRange condition checks if the agent is within a range of target,
+## defined by distance_min and distance_max.
+## Returns SUCCESS if the agent is within the defined range;
+## otherwise, returns FAILURE.
+
+@export var distance_min: float
+@export var distance_max: float
+@export var target_var := "target"
+
+var _min_distance_squared: float
+var _max_distance_squared: float
+
+
+# Called to generate a display name for the task.
+func _generate_name() -> String:
+    return "InRange (%d, %d) of %s" % [distance_min, distance_max,
+        LimboUtility.decorate_var(target_var)]
+
+
+# Called to initialize the task.
+func _setup() -> void:
+    _min_distance_squared = distance_min * distance_min
+    _max_distance_squared = distance_max * distance_max
+
+
+# Called when the task is executed.
+func _tick(_delta: float) -> Status:
+    var target: Node2D = blackboard.get_var(target_var, null)
+    if not is_instance_valid(target):
+        return FAILURE
+
+    var dist_sq: float = agent.global_position.distance_squared_to(target.global_position)
+    if dist_sq >= _min_distance_squared and dist_sq <= _max_distance_squared:
+        return SUCCESS
+    else:
+        return FAILURE

demo/demo/ai/tasks/select_flanking_pos.gd

@@ -13,12 +13,21 @@ extends BTAction
 ## SelectFlankingPos on the side of a target, and return SUCCESS.
 ## Returns FAILURE, if the target is not valid.
 
+enum AgentSide {
+	CLOSEST,
+	FARTHEST,
+	BACK,
+	FRONT,
+}
+
 ## Blackboard variable that holds current target (should be a Node2D instance).
 @export var target_var: String = "target"
 
 ## Should closest side be selected?
 @export var closest_side: bool = false
 
+@export var flank_side: AgentSide = AgentSide.CLOSEST
+
 ## Minimum range relative to the target.
 @export var range_min: int = 300
 
@@ -26,15 +35,15 @@ extends BTAction
 @export var range_max: int = 400
 
 ## Blackboard variable that will be used to store selected position.
-@export var position_var: String = "flank_pos"
+@export var position_var: String = "pos"
 
 # Display a customized name (requires @tool).
 func _generate_name() -> String:
-	return "SelectFlankingPos  target: %s  range: [%s, %s]  closest: %s  ➜%s" % [
+	return "SelectFlankingPos  target: %s  range: [%s, %s]  side: %s  ➜%s" % [
 		LimboUtility.decorate_var(target_var),
 		range_min,
 		range_max,
-		closest_side,
+		AgentSide.keys()[flank_side],
 		LimboUtility.decorate_var(position_var)]
 
 # Called each time this task is ticked (aka executed).
@@ -43,10 +52,19 @@ func _tick(_delta: float) -> Status:
 	if not is_instance_valid(target):
 		return FAILURE
 
-	var dir: float = signf(target.global_position.x - agent.global_position.x)
+	var dir: float
-	if closest_side:
+	match flank_side:
-		dir *= -1.0
+		AgentSide.FARTHEST:
+			dir = signf(target.global_position.x - agent.global_position.x)
+		AgentSide.CLOSEST:
+			dir = -signf(target.global_position.x - agent.global_position.x)
+		AgentSide.BACK:
+			dir = -target.get_facing()
+		AgentSide.FRONT:
+			dir = target.get_facing()
+
 	var flank_pos: Vector2 = target.global_position
 	flank_pos.x += dir * randf_range(range_min, range_max)
 	blackboard.set_var(position_var, flank_pos)
 	return SUCCESS
+

demo/demo/ai/trees/enemy_melee_combo.tres

@@ -39,6 +39,7 @@ children = [SubResource("BTPlayAnimation_qiw21"), SubResource("BTRandomWait_xlud
 script = ExtResource("2_ifiw3")
 target_var = "target"
 closest_side = true
+flank_side = 0
 range_min = 300
 range_max = 400
 position_var = "pos"

demo/demo/ai/trees/enemy_melee_nuanced.tres

@@ -53,6 +53,7 @@ speed = 1.5
 script = ExtResource("2_fl3fr")
 target_var = "_target"
 closest_side = false
+flank_side = 1
 range_min = 400
 range_max = 600
 position_var = "_flank_pos"

demo/demo/ai/trees/enemy_melee_simple.tres

@@ -70,7 +70,7 @@ resource_name = "AnimationPlayer"
 [sub_resource type="BTPlayAnimation" id="BTPlayAnimation_ppmxd"]
 await_completion = 2.0
 animation_player = SubResource("BBNode_s8evu")
-animation_name = &"attack_3"
+animation_name = &"attack_1"
 
 [sub_resource type="BTSequence" id="BTSequence_ww5v2"]
 custom_name = "Melee attack"

demo/demo/ai/trees/enemy_melee_skirmisher.tres

@@ -0,0 +1,156 @@
+[gd_resource type="BehaviorTree" load_steps=36 format=3 uid="uid://qqmjvbeibatn"]
+
+[ext_resource type="Script" path="res://demo/ai/tasks/get_first_in_group.gd" id="1_oiqfa"]
+[ext_resource type="Script" path="res://demo/ai/tasks/select_flanking_pos.gd" id="2_b4wcf"]
+[ext_resource type="Script" path="res://demo/ai/tasks/face_target.gd" id="3_hwbvn"]
+[ext_resource type="Script" path="res://demo/ai/tasks/arrive_pos.gd" id="3_pn7sq"]
+[ext_resource type="Script" path="res://demo/ai/tasks/in_range.gd" id="4_330a2"]
+[ext_resource type="Script" path="res://demo/ai/tasks/back_away.gd" id="5_morrs"]
+
+[sub_resource type="BlackboardPlan" id="BlackboardPlan_46tbn"]
+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/fast_speed/name = "fast_speed"
+var/fast_speed/type = 3
+var/fast_speed/value = 600.0
+var/fast_speed/hint = 1
+var/fast_speed/hint_string = "10,1000,10"
+var/slow_speed/name = "slow_speed"
+var/slow_speed/type = 3
+var/slow_speed/value = 300.0
+var/slow_speed/hint = 1
+var/slow_speed/hint_string = "10,1000,10"
+
+[sub_resource type="BBNode" id="BBNode_nrd4b"]
+saved_value = NodePath("AnimationPlayer")
+resource_name = "AnimationPlayer"
+
+[sub_resource type="BTPlayAnimation" id="BTPlayAnimation_qiw21"]
+animation_player = SubResource("BBNode_nrd4b")
+animation_name = &"idle"
+blend = 0.1
+
+[sub_resource type="BTRandomWait" id="BTRandomWait_xlud8"]
+min_duration = 1.5
+max_duration = 3.0
+
+[sub_resource type="BTAction" id="BTAction_ulbrf"]
+script = ExtResource("1_oiqfa")
+group = &"player"
+output_var = "target"
+
+[sub_resource type="BTSequence" id="BTSequence_yhjh1"]
+custom_name = "Pause before action"
+children = [SubResource("BTPlayAnimation_qiw21"), SubResource("BTRandomWait_xlud8"), SubResource("BTAction_ulbrf")]
+
+[sub_resource type="BBNode" id="BBNode_wpj6d"]
+saved_value = NodePath("AnimationPlayer")
+resource_name = "AnimationPlayer"
+
+[sub_resource type="BTPlayAnimation" id="BTPlayAnimation_olf37"]
+animation_player = SubResource("BBNode_wpj6d")
+animation_name = &"walk"
+blend = 0.1
+speed = 1.2
+
+[sub_resource type="BTAction" id="BTAction_g5ayy"]
+script = ExtResource("2_b4wcf")
+target_var = "target"
+closest_side = false
+flank_side = 2
+range_min = 100
+range_max = 100
+position_var = "flank_pos"
+
+[sub_resource type="BTAction" id="BTAction_tv4lt"]
+script = ExtResource("3_pn7sq")
+target_position_var = "flank_pos"
+speed_var = "fast_speed"
+tolerance = 50.0
+
+[sub_resource type="BTSequence" id="BTSequence_rgwic"]
+children = [SubResource("BTAction_g5ayy"), SubResource("BTAction_tv4lt")]
+
+[sub_resource type="BTTimeLimit" id="BTTimeLimit_xek5v"]
+time_limit = 4.0
+children = [SubResource("BTSequence_rgwic")]
+
+[sub_resource type="BTAction" id="BTAction_kidxn"]
+script = ExtResource("3_hwbvn")
+target_var = "target"
+
+[sub_resource type="BTCondition" id="BTCondition_uk4dg"]
+script = ExtResource("4_330a2")
+distance_min = 50.0
+distance_max = 170.0
+target_var = "target"
+
+[sub_resource type="BTWait" id="BTWait_tadkc"]
+duration = 0.1
+
+[sub_resource type="BBNode" id="BBNode_s8evu"]
+saved_value = NodePath("AnimationPlayer")
+resource_name = "AnimationPlayer"
+
+[sub_resource type="BTPlayAnimation" id="BTPlayAnimation_ppmxd"]
+await_completion = 2.0
+animation_player = SubResource("BBNode_s8evu")
+animation_name = &"attack_3"
+
+[sub_resource type="BTSequence" id="BTSequence_ww5v2"]
+custom_name = "Melee attack"
+children = [SubResource("BTCondition_uk4dg"), SubResource("BTWait_tadkc"), SubResource("BTPlayAnimation_ppmxd")]
+
+[sub_resource type="BBNode" id="BBNode_wtnf2"]
+saved_value = NodePath("AnimationPlayer")
+resource_name = "AnimationPlayer"
+
+[sub_resource type="BTPlayAnimation" id="BTPlayAnimation_k86qc"]
+animation_player = SubResource("BBNode_wtnf2")
+animation_name = &"idle"
+blend = 0.1
+
+[sub_resource type="BTRandomWait" id="BTRandomWait_m447o"]
+min_duration = 0.3
+max_duration = 0.6
+
+[sub_resource type="BTSequence" id="BTSequence_b00uw"]
+custom_name = "Short break"
+children = [SubResource("BTPlayAnimation_k86qc"), SubResource("BTRandomWait_m447o")]
+
+[sub_resource type="BBNode" id="BBNode_3iqcf"]
+saved_value = NodePath("AnimationPlayer")
+resource_name = "AnimationPlayer"
+
+[sub_resource type="BTPlayAnimation" id="BTPlayAnimation_ee0ff"]
+animation_player = SubResource("BBNode_3iqcf")
+animation_name = &"walk"
+blend = 0.1
+speed = -0.7
+
+[sub_resource type="BTAction" id="BTAction_4ye2y"]
+script = ExtResource("5_morrs")
+speed_var = "slow_speed"
+max_angle_deviation = 0.7
+
+[sub_resource type="BTTimeLimit" id="BTTimeLimit_cns1i"]
+time_limit = 1.5
+children = [SubResource("BTAction_4ye2y")]
+
+[sub_resource type="BTSequence" id="BTSequence_y12eg"]
+custom_name = "Back away"
+children = [SubResource("BTPlayAnimation_ee0ff"), SubResource("BTTimeLimit_cns1i")]
+
+[sub_resource type="BTSequence" id="BTSequence_1xfnq"]
+custom_name = "Skirmish"
+children = [SubResource("BTPlayAnimation_olf37"), SubResource("BTTimeLimit_xek5v"), SubResource("BTAction_kidxn"), SubResource("BTSequence_ww5v2"), SubResource("BTSequence_b00uw"), SubResource("BTSequence_y12eg")]
+
+[sub_resource type="BTSequence" id="BTSequence_pxl2k"]
+children = [SubResource("BTSequence_yhjh1"), SubResource("BTSequence_1xfnq")]
+
+[resource]
+blackboard_plan = SubResource("BlackboardPlan_46tbn")
+root_task = SubResource("BTSequence_pxl2k")

demo/demo/ai/trees/enemy_ranged.tres

@@ -75,6 +75,7 @@ children = [SubResource("BTSequence_0gdqn")]
 script = ExtResource("2_vbh52")
 target_var = "target"
 closest_side = true
+flank_side = 0
 range_min = 400
 range_max = 1000
 position_var = "shoot_pos"