Prevent crashes due to freed references

game/project.godot

@@ -15,12 +15,18 @@ _global_script_classes=[ {
 "path": "res://scenes/combat/combat.gd"
 }, {
 "base": "Spatial",
+"class": "DraggablePart",
+"language": "GDScript",
+"path": "res://scenes/draggable_parts/DraggablePart.gd"
+}, {
+"base": "Spatial",
 "class": "Ghoul",
 "language": "GDScript",
 "path": "res://scenes/ghoul/Ghoul.gd"
 } ]
 _global_script_class_icons={
 "Combat": "",
+"DraggablePart": "",
 "Ghoul": ""
 }
 

game/scenes/Main.tscn

@@ -1,4 +1,4 @@
-[gd_scene load_steps=8 format=2]
+[gd_scene load_steps=9 format=2]
 
 [ext_resource path="res://scenes/ghoul_assembly/Ghoul Assembly.tscn" type="PackedScene" id=1]
 [ext_resource path="res://scenes/ground/Ground.tscn" type="PackedScene" id=2]
@@ -7,12 +7,12 @@
 [ext_resource path="res://scenes/Decorative/AssemblyDecorations.tscn" type="PackedScene" id=5]
 [ext_resource path="res://scenes/GameStateManagerFactoryServiceProvider.gd" type="Script" id=6]
 [ext_resource path="res://scenes/Camera.gd" type="Script" id=7]
+[ext_resource path="res://GameOverText.tscn" type="PackedScene" id=8]
 
 [node name="Main" type="Spatial"]
 
 [node name="Camera" type="Camera" parent="."]
 transform = Transform( -3.78552e-08, 0.5, -0.866025, 2.18557e-08, 0.866025, 0.5, 1, 1.95399e-14, -4.37114e-08, -33.0352, 11.2092, 13.053 )
-far = 1732.5
 script = ExtResource( 7 )
 fight_pos_path = NodePath("../camera_fight_target")
 
@@ -36,4 +36,6 @@ gameStatePath = NodePath("../GameStateManagerFactoryServiceProvider")
 script = ExtResource( 6 )
 
 [node name="camera_fight_target" type="Spatial" parent="."]
-transform = Transform( -1.62921e-07, 0.34202, -0.939693, 0, 0.939693, 0.34202, 1, 5.57222e-08, -1.53095e-07, -28.4427, 13.7961, 18.1236 )
+transform = Transform( -1.62921e-07, 0.34202, -0.939693, 0, 0.939693, 0.34202, 1, 5.57222e-08, -1.53095e-07, -31.9886, 24.9668, 36.6855 )
+
+[node name="GameOverText" parent="." instance=ExtResource( 8 )]

game/scenes/draggable_parts/DraggablePart.gd

@@ -15,6 +15,7 @@ var delivery_index: int;
 var dragged: bool = false
 
 signal select_part(part)
+signal removed(deliver_index)
 
 # Called when the node enters the scene tree for the first time.
 # warning-ignore:return_value_discarded
@@ -49,7 +50,11 @@ func onDeselect():
 #Stuff to do when added to ghoul.
 func onAdd():
 	self.delivery.on_part_used(delivery_index)
-	self.queue_free()
+	remove()
+
+func remove():
+	emit_signal("removed", delivery_index)
+	queue_free()
 
 func _on_DragDetector_input_event(_camera, event, _click_position, _click_normal, _shape_idx):
 	if event is InputEventMouseButton:
@@ -63,6 +68,7 @@ func _on_DragDetector_mouse_exited():
 	tooltip.visible = false
 
 func _process(_delta):
+	global_transform.basis = get_viewport().get_camera().global_transform.basis
 	if tooltip.visible:
 		var pos = get_viewport().get_mouse_position()
 		pos.x -= tooltip.rect_size.x / 2

game/scenes/enemies/EnemySpawner.gd

@@ -21,6 +21,8 @@ var first_in_line = null
 
 func set_next(next):
 	last_spawn = next
+	if next == null:
+		first_in_line = null
 
 # Called when the node enters the scene tree for the first time.
 func _ready():
@@ -33,13 +35,13 @@ func _ready():
 # Called every frame. 'delta' is the elapsed time since the previous frame.
 func _process(delta):
 	currentCooldown -= delta
-	if spawnCount and currentCooldown <= 0:
+	if spawnCount > 0 and currentCooldown <= 0:
 		call_deferred("spawn_enemy")
 		spawnCount -= 1
 		currentCooldown = spawnCooldown + rng.randf() * spawnVariance
 
 func onSpawneeDeath():
-	if spawnCount < 1 and last_spawn == null:
+	if spawnCount <= 0 and last_spawn == null:
 		self.done = true
 		combat.onSpawnerDone()
 

game/scenes/enemies/enemy.gd

@@ -1,5 +1,6 @@
 extends Spatial
 
+signal removed
 
 var kind;
 
@@ -59,11 +60,15 @@ func set_prev(prev):
 func take_damage(damage):
 	health -= damage
 	if health <= 0:
-		prev_in_line.set_next(next_in_line)
-		if (next_in_line != null):
-			next_in_line.set_prev(prev_in_line)
-		self.spawner.onSpawneeDeath()
-		queue_free()
+		remove()
+
+func remove():
+	prev_in_line.set_next(next_in_line)
+	if next_in_line != null:
+		next_in_line.set_prev(prev_in_line)
+	self.spawner.onSpawneeDeath()
+	emit_signal("removed")
+	queue_free()
 
 # Called when the node enters the scene tree for the first time.
 func _ready():
@@ -116,5 +121,5 @@ func _process(delta):
 
 		if global_transform.origin.z <= 0:
 			combat.damage_castle(1)
-			take_damage(health)
+			remove()
 

game/scenes/ghoul/Ghoul.gd

@@ -3,6 +3,7 @@ extends Spatial
 class_name Ghoul
 
 signal select_ghoul(ghoul)
+signal removed
 
 onready var selectionSprite = $SelectionSprite
 onready var healthbar = $Healthbar
@@ -14,6 +15,7 @@ var lane = 0
 var column = 0
 var enemy_spawner = null
 var parts: Array = []
+var body
 
 var damage_taken = 0
 var attack_cooldown_left = 0.0
@@ -88,15 +90,23 @@ func take_damage(amount: int, ranged = false):
 	healthbar.transform = initial_health_transform.scaled(Vector3(health_factor, 1, 1))
 
 var target = null
-var is_attacking = false
+
+func invalidate_target():
+	target = null
+
+func set_target(enemy):
+	if enemy != target:
+		target = enemy
+		target.connect("removed", self, "invalidate_target")
+
+func clear_target():
+	target.disconnect("removed", self, "invalidate_target")
+	target = null
 
 func try_attack():
-	if attack_cooldown_left <= 0.0 && !is_attacking:
-		if is_instance_valid(enemy_spawner.first_in_line):
-			target = enemy_spawner.first_in_line
-		else:
-			target = null
-		if target != null and target.has_method("get_global_transform"):
+	if attack_cooldown_left <= 0.0 && target == null:
+		if enemy_spawner.first_in_line != null:
+			set_target(enemy_spawner.first_in_line)
 			var target_pos = target.global_transform.origin 
 			var d = target_pos - global_transform.origin
 			if d.length() < MELEE_RANGE:
@@ -106,14 +116,14 @@ func try_attack():
 				if attack_cooldown_left < animation_length:
 					var animation_speed = animation_length/attack_cooldown_left
 					$AnimationPlayer.play("attack", -1, animation_speed)
-				is_attacking = true
+			else:
+				clear_target()
 
 func deal_damage():
-	if !is_instance_valid(target):
-		target = null
 	if target != null:
-		target.take_damage(melee)
-	is_attacking = false
+		var to_damage = target # Since take_damage may remove
+		clear_target() # Must be done bevore removal
+		to_damage.take_damage(melee)
 
 func add_ability(ability):
 	abilities.append(ability)
@@ -124,14 +134,21 @@ func add_ability(ability):
 	if ability.has_method("process_stats_third_pass"):
 		third_pass_abilities.append(ability)
 
+func add_body(ghoul_body):
+	body = ghoul_body
+	add_child(body)
+
 func _process(delta):
+	body.global_transform.basis = get_viewport().get_camera().global_transform.basis
+
 	if !active:
 		return
 
 	if damage_taken >= max_health: # max_health can vary
 		for ability in abilities:
 			Abilities.on_ability_removed(ability)
 		combat.remove_ghoul(lane, column)
+		emit_signal("removed")
 		queue_free()
 		return
 

game/scenes/ghoul_assembly/GhoulAssembly.gd

@@ -71,7 +71,7 @@ func try_add_part(part_name):
 
 			# Body
 			ghoul_body = part
-			ghoul_in_progress.add_child(ghoul_body)
+			ghoul_in_progress.add_body(ghoul_body)
 			ghoul_body.transform.origin.x = -0.7
 			return true
 	elif ghoul_in_progress != null:
@@ -94,27 +94,38 @@ func on_ghoul_deployed():
 	ghoul_body = null	
 	ghoul_in_progress = null
 
-func _on_part_select_event(part):
-	if is_instance_valid(selected_part):
-		selected_part = null
 
+func invalidate_selected_part(_i):
+	selected_part = null
+
+func set_selected_part(part):
+	if part != selected_part:
+		selected_part = part
+		selected_part.connect("removed", self, "invalidate_selected_part")
+		selected_part.onSelect()
+
+func clear_selected_part():
+	selected_part.disconnect("removed", self, "invalidate_selected_part")
+	selected_part = null
+
+
+func _on_part_select_event(part):
 	if selected_part != null:
 		selected_part.onDeselect()
 		if selected_part == part:
-			selected_part = null
+			clear_selected_part()
 		else:
-			selected_part = part
-			selected_part.onSelect()
+			set_selected_part(part)
 	else:
-		selected_part = part
-		selected_part.onSelect()
+		set_selected_part(part)
 
 func _on_AssemblyArea_input_event(_camera, event, _click_position, _click_normal, _shape_idx):
 	if selected_part != null:
 		if event is InputEventMouseButton:
 			if event.button_index == BUTTON_LEFT and event.pressed:
 				if try_add_part(selected_part.partType):
-					selected_part.onAdd()
-					selected_part = null #Clear selection when adding
+					var part_to_add = selected_part # Since onAdd removes
+					clear_selected_part() # Must be done bevore removal
+					part_to_add.onAdd()
 					if ghoul_body.is_complete():
 						ghoul_in_progress.init(combat)

game/scenes/part_delivery/PartDelivery.gd

@@ -77,32 +77,22 @@ func create_part(partType, index):
 	var newPart: Spatial = packed_part.instance()
 	var ghoulAssembly = get_node(ghoulAssemblyPath)
 	newPart.initialize(newPartSprite, partType, ghoulAssembly, self, index)
-	get_tree().root.call_deferred("add_child", newPart)
 	return newPart
 
 func fillDropOffs():
-	var seeded_parts = []
-	seeded_parts.append(arm_types[rng.randi() % arm_types.size()])
-	seeded_parts.append(body_types[rng.randi() % body_types.size()])
-	seeded_parts.append(head_types[rng.randi() % head_types.size()])
-	seeded_parts.append(leg_types[rng.randi() % leg_types.size()])
-	seeded_parts.shuffle()
-
 	var i = 0
 	for dropOff in dropOffs:
-		add_part_at_dropoff(i, dropOff)
+		add_part_at_dropoff(i)
 
 		i += 1
 
 
-func add_part_at_dropoff(i: int, dropOff):
+func add_part_at_dropoff(i: int):
 	var has_legs = false
 	var has_head = false
 	var has_body = false
 	var has_arms = false
 	for slot in slots:
-		if !is_instance_valid(slot):
-			slot = null
 		if slot is DraggablePart and slot != null:
 			if "ARM" in slot.partType:
 				has_arms = true
@@ -115,34 +105,48 @@ func add_part_at_dropoff(i: int, dropOff):
 
 	if parts_to_give > 0:
 		var part_type
-		if not has_arms:
-			part_type = arm_types[rng.randi() % arm_types.size()]
+		if not has_body:
+			part_type = body_types[rng.randi() % body_types.size()]
 		elif not has_legs:
 			part_type = leg_types[rng.randi() % leg_types.size()]
-		elif not has_body:
-			part_type = body_types[rng.randi() % body_types.size()]
 		elif not has_head:
 			part_type = head_types[rng.randi() % arm_types.size()]
+		elif not has_arms:
+			part_type = arm_types[rng.randi() % arm_types.size()]
 		else:
 			part_type = packedSpriteScenes.keys()[rng.randi() % packedSpriteScenes.keys().size()]
-
-		var newDraggablePart = create_part(part_type, i)
-		newDraggablePart.global_transform = dropOff.global_transform.translated(Vector3(0, 2.5, 0))
-		slots[i] = newDraggablePart
+
+		set_slot(i, create_part(part_type, i))
 		parts_to_give -= 1
 
+func invalidate_slot(i: int):
+	slots[i] = null
 
-func on_part_used(part_index: int):
-	add_part_at_dropoff(part_index, dropOffs[part_index])
+func set_slot(i: int, part):
+	if part != slots[i]:
+		slots[i] = part
+		get_tree().root.add_child(slots[i])
+		slots[i].global_transform = dropOffs[i].global_transform.translated(Vector3(0, 2.5, 0))
+		slots[i].global_transform.basis = get_viewport().get_camera().global_transform.basis
+		slots[i].connect("removed", self, "invalidate_slot")
 
+func clear_slot(i: int):
+	if slots[i] != null:
+		get_tree().root.remove_child(slots[i])
+		slots[i].disconnect("removed", self, "invalidate_slot")
+		slots[i] = null
 
+func on_part_used(part_index: int):
+	clear_slot(part_index)
+	add_part_at_dropoff(part_index)
 
 func clear_current_parts():
 	var i = 0
 	for dropOff in dropOffs:
-		if slots[i] != null and is_instance_valid(slots[i]):
-			slots[i].queue_free()
-			slots[i] = null
+		if slots[i] != null:
+			var to_remove = slots[i] # Since remove removes
+			clear_slot(i) # Must be done bevore removal
+			to_remove.remove()
 		i += 1
 
 func on_assembly_start():