Fixed Turret incorrectly using references to freed objects

.gitignore

@@ -22,4 +22,5 @@ export_presets.cfg
 
 # Mono-specific ignores
 .mono/
-data_*/
+data_*/
+.vscode/launch.json

.vscode/launch.json

@@ -8,7 +8,7 @@
       "name": "GDScript Godot",
       "type": "godot",
       "request": "launch",
-      "project": "C:\\Users\\jakob\\Documents\\Godot\\Wumper",
+      "project": "C:\\Users\\Jakob F\\Documents\\Godot\\Wumper",
       "port": 6007,
       "address": "127.0.0.1",
       "launch_game_instance": true,

src/Actors/Enemies/Machines/Turret.gd

@@ -3,7 +3,7 @@ extends KinematicBody2D
 # Declare member variables here. Examples:
 # var a: int = 2
 # var b: String = "text"
-onready var sightline: RayCast2D = $RayCast2D
+onready var sightline: RayCast2D = $Sightline
 onready var turret_state_machine = $TurretStateMachine
 onready var lock_on_timer = $LockOnTimer
 onready var sight_lost_timer = $SightLostTimer
@@ -19,8 +19,8 @@ onready var original_rotation = rotation
 onready var rotation_speed_divider = 80
 # TODO causes oscilation
 onready var min_rotation_speed = deg2rad(0.3)
-
-var prey = null
+# TODO Bug when dying in the wrong state, missing prey instance
+var prey_ref = weakref(null)
 # Ray that goes from the turret to the target
 var target_ray
 
@@ -29,13 +29,18 @@ var target_ray
 func _ready() -> void:
 	$AnimationPlayer.play("Turret Rotation")
 
+func prey():
+	return prey_ref.get_ref()
 
 func searching():
+	$AnimationPlayer.play("Turret Rotation")
 	if sightline.is_colliding():
 		# The collider returns not the area or body it hit, but the parent of them
 		var collider = sightline.get_collider()
 		if collider.is_in_group("player"):
-			prey = collider
+			print_debug(is_tracking_prey())
+			prey_ref = weakref(collider)
+			print_debug(is_tracking_prey())
 
 
 # TODO should this stand still?
@@ -44,7 +49,8 @@ func start_locking():
 	add_child(target_ray)
 	target_ray.enabled = true
 	target_ray.exclude_parent = true
-	target_ray.set_cast_to(to_local(prey.position))
+	if(prey() != null):
+		target_ray.set_cast_to(to_local(prey().position))
 	$AnimationPlayer.stop(false)
 
 	lock_on_timer.start()
@@ -53,6 +59,8 @@ func start_locking():
 func is_locked_on_target():
 	return lock_on_timer.is_stopped()
 
+func is_tracking_prey():
+	return true if(prey() != null) else false
 
 # TODO simplify/split this method
 func shooting():
@@ -69,22 +77,23 @@ func shooting():
 	)
 	if sightline.is_colliding():
 		# The collider returns not the area or body it hit, but the parent of them
+		# TODO Sight could be a cone instead of a ray
 		var collider = sightline.get_collider()
 		if collider.is_in_group("player"):
 			sight_lost_timer.stop()
-			target_ray.cast_to = to_local(prey.position)
+			target_ray.cast_to = to_local(prey().position)
 		else:
 			if (
 				sight_lost_timer.get_time_left() < 0.1
 				&& sight_lost_timer.get_time_left() > 0
 			):
-				prey = null
+				prey_ref = weakref(null)
 				target_ray.queue_free()
 				return
 			if sight_lost_timer.is_stopped():
 				sight_lost_timer.start()
-			else:
-				target_ray.cast_to = to_local(prey.position)
+			elif(prey() != null):
+				target_ray.cast_to = to_local(prey().position)
 
 	spawn_projectile()
 

src/Actors/Enemies/Machines/Turret.tscn

@@ -39,7 +39,7 @@ position = Vector2( 0, -0.103346 )
 scale = Vector2( 0.310271, 1.02855 )
 shape = SubResource( 1 )
 
-[node name="RayCast2D" type="RayCast2D" parent="."]
+[node name="Sightline" type="RayCast2D" parent="."]
 enabled = true
 cast_to = Vector2( 0, 1e+07 )
 collision_mask = 59

src/Actors/Enemies/Machines/TurretRayCast.gd

@@ -1,14 +0,0 @@
-extends RayCast2D
-
-# Declare member variables here. Examples:
-# var a: int = 2
-# var b: String = "text"
-
-
-# Called when the node enters the scene tree for the first time.
-func _ready() -> void:
-	pass  # Replace with function body.
-
-# Called every frame. 'delta' is the elapsed time since the previous frame.
-func _process(delta: float) -> void:
-	

src/Actors/Enemies/Machines/TurretStateMachine.gd

@@ -52,10 +52,11 @@ func _get_transition(_delta):
 	# TODO why only this way?
 	parent.get_node("StateLabel").text = self.state
 	var new_state
-	if parent.prey != null && self.state == "searching":
+	if parent.is_tracking_prey() && self.state == "searching":
 		parent.start_locking()
 		new_state = "locking"
-	if parent.prey == null && self.state == "shooting":
+	# TODO Helper function with null check and reference check
+	if !parent.is_tracking_prey() && self.state == "shooting":
 		new_state = "searching"
 	if self.state == "locking" && parent.is_locked_on_target():
 		new_state = "shooting"

src/Levels/Plattforms Level.tscn

@@ -5,8 +5,8 @@
 [ext_resource path="res://src/Contraptions/Platform/Spring.tscn" type="PackedScene" id=3]
 [ext_resource path="res://src/Environment/Background.tscn" type="PackedScene" id=4]
 [ext_resource path="res://src/Contraptions/Platform/Track.tscn" type="PackedScene" id=5]
+[ext_resource path="res://src/Actors/Enemies/Machines/Turret.tscn" type="PackedScene" id=6]
 [ext_resource path="res://src/UserInterface/Buttons/UI.tscn" type="PackedScene" id=7]
-[ext_resource path="res://src/Actors/Enemies/Machines/Turret.tscn" type="PackedScene" id=8]
 
 [sub_resource type="NavigationPolygon" id=1]
 vertices = PoolVector2Array( 16, 16, 0, 16, 0, 0, 16, 0 )
@@ -78,9 +78,9 @@ scale = Vector2( 2.83999, 0.56 )
 [node name="KinematicBody2D" parent="Track" index="0"]
 position = Vector2( 8, 0 )
 
-[node name="Turret" parent="." instance=ExtResource( 8 )]
-position = Vector2( 479.52, 464 )
-scale = Vector2( 0.5, 0.5 )
+[node name="Turret" parent="." instance=ExtResource( 6 )]
+position = Vector2( 479, 520 )
+scale = Vector2( 0.4, 0.4 )
 
 [editable path="Spring4"]
 [editable path="Track"]