Changing bridge zindex and body set layer and mask from bridge process function to each bridge area on_body_entered and on_body_exited. This change optimize code avoiding to set zindex of bridge and body layers and mask each frame. The script bridge is not necessary anymore.

Interactables/bellow_bridge_area.gd

@@ -1,23 +1,19 @@
 extends Area2D
 class_name BellowBridgeArea
 
-var is_character_bellow_bridge: bool = false
-var character_body: Node2D = null
 
 func _on_body_entered(_body: Node2D) -> void:
-	self._set_character_body_bellow_bridge(_body, true)
+	if _body is BaseCharacter:
+		var bridge: TileMapLayer = self.get_parent()
+		bridge.z_index = 2
+		_body.set_collision_layer_value(4, false)
+		_body.set_collision_mask_value(4, false)
+		print("entering bellow bridge")
 
 func _on_body_exited(_body: Node2D) -> void:
-	self._set_character_body_bellow_bridge(_body, false)
-	
-func _set_character_body_bellow_bridge(_body: Node2D, _state: bool) -> void:
 	if _body is BaseCharacter:
-		self.is_character_bellow_bridge = _state
+		var bridge: TileMapLayer = self.get_parent()
-		self.character_body = _body
+		bridge.z_index = 0
-		print("bellow bridge: " + str(_state))
+		_body.set_collision_layer_value(4, true)
-
+		_body.set_collision_mask_value(4, true)
-func get_character_body_bellow_bridge() -> bool:
+		print("exiting bellow bridge")
-	return self.is_character_bellow_bridge
-	
-func get_body() -> Node2D:
-	return self.character_body

Interactables/on_bridge_area.gd

@@ -1,25 +1,22 @@
 extends Area2D
 class_name BridgeArea
 
-var character_body: Node2D = null
-var is_character_on_bridge: bool = false
-
 func _on_body_entered(_body: Node2D) -> void:
-	#_body.update_collision_layer_mask("in")
+	if _body is BaseCharacter:
-	self._set_character_body_on_bridge(_body, true)
+		_body.set_collision_layer_value(8, false)
+		_body.set_collision_mask_value(8, false)
+		_body.set_collision_layer_value(1, false)
+		_body.set_collision_mask_value(1, false)
+		_body.set_collision_layer_value(2, true)
+		_body.set_collision_mask_value(2, true)
+		print("entering on bridge")
 
 func _on_body_exited(_body: Node2D) -> void:
-	#_body.update_collision_layer_mask("out")
-	self._set_character_body_on_bridge(_body, false)
-
-func _set_character_body_on_bridge(_body: Node2D, _state: bool) -> void:
 	if _body is BaseCharacter:
-		self.character_body = _body
+		_body.set_collision_layer_value(8, true)
-		self.is_character_on_bridge = _state
+		_body.set_collision_mask_value(8, true)
-		print("on bridge: " + str(_state))
+		_body.set_collision_layer_value(1, true)
-
+		_body.set_collision_mask_value(1, true)
-func get_character_body_on_bridge() -> bool:
+		_body.set_collision_layer_value(2, false)
-	return self.is_character_on_bridge
+		_body.set_collision_mask_value(2, false)
-	
+		print("exiting on bridge")
-func get_body() -> Node2D:
-	return self.character_body

Terrain/bridge.gd

@@ -1,39 +0,0 @@
-extends TileMapLayer
-class_name Bridge
-
-@export_category("Objects")
-@export var bellow_bridge_area: Area2D
-@export var on_bridge_area: Area2D
-
-
-func _process(_delta: float) -> void:
-	var character_body_bellow_bridge: Node2D = bellow_bridge_area.get_body()
-	var character_body_on_bridge: Node2D = on_bridge_area.get_body()
-	
-	if character_body_bellow_bridge:
-		if bellow_bridge_area.get_character_body_bellow_bridge():
-			character_body_bellow_bridge.set_collision_layer_value(4, false)
-			character_body_bellow_bridge.set_collision_mask_value(4, false)
-			self.z_index = 2
-		else:
-			character_body_bellow_bridge.set_collision_layer_value(4, true)
-			character_body_bellow_bridge.set_collision_mask_value(4, false)
-			self.z_index = 0
-
-	if character_body_on_bridge:
-		if on_bridge_area.get_character_body_on_bridge():
-			character_body_on_bridge.set_collision_layer_value(8, false)
-			character_body_on_bridge.set_collision_mask_value(8, false)
-			character_body_on_bridge.set_collision_layer_value(1, false)
-			character_body_on_bridge.set_collision_mask_value(1, false)
-			character_body_on_bridge.set_collision_layer_value(2, true)
-			character_body_on_bridge.set_collision_mask_value(2, true)
-
-		else:
-			character_body_on_bridge.set_collision_layer_value(8, true)
-			character_body_on_bridge.set_collision_mask_value(8, true)
-			character_body_on_bridge.set_collision_layer_value(1, true)
-			character_body_on_bridge.set_collision_mask_value(1, true)
-			character_body_on_bridge.set_collision_layer_value(2, false)
-			character_body_on_bridge.set_collision_mask_value(2, false)
-			

Terrain/bridge.gd.uid

@@ -1 +0,0 @@
-uid://jqtagkf51o2

Terrain/terrain_manager.tscn

@@ -1,4 +1,4 @@
-[gd_scene load_steps=37 format=4 uid="uid://dkfrltbqlycy0"]
+[gd_scene load_steps=36 format=4 uid="uid://dkfrltbqlycy0"]
 
 [ext_resource type="Texture2D" uid="uid://byqnrxn13bbnp" path="res://Terrain/Water/Water.png" id="1_1aeul"]
 [ext_resource type="Texture2D" uid="uid://b6wic25dxw41l" path="res://Terrain/Water/Foam/Foam.png" id="2_qnvmo"]
@@ -11,7 +11,6 @@
 [ext_resource type="Texture2D" uid="uid://ljb2glg7ikd3" path="res://Terrain/Ground/Shadows.png" id="9_osja2"]
 [ext_resource type="Texture2D" uid="uid://dvdid120sw0q3" path="res://Terrain/Bridge/Bridge_All.png" id="10_v8sh6"]
 [ext_resource type="Script" uid="uid://dirg5mq4y4nk0" path="res://Interactables/on_bridge_area.gd" id="11_oe1b3"]
-[ext_resource type="Script" uid="uid://jqtagkf51o2" path="res://Terrain/bridge.gd" id="11_pko0k"]
 [ext_resource type="Script" uid="uid://bg2dqq8ebhkjs" path="res://Interactables/bellow_bridge_area.gd" id="13_qwqgt"]
 
 [sub_resource type="TileSetAtlasSource" id="TileSetAtlasSource_qnvmo"]
@@ -282,13 +281,10 @@ tile_set = SubResource("TileSet_osja2")
 tile_map_data = PackedByteArray("AAALAAkAAAAAAAAAAAAOAAkAAAACAAAAAAAUAAoAAAACAAAAAAAUAAwAAAACAAIAAAARAAwAAAAAAAIAAAALAAsAAAAAAAIAAAALAAoAAAAAAAEAAAAMAAkAAAABAAAAAAANAAkAAAABAAAAAAAPAAoAAAABAAAAAAAQAAoAAAABAAAAAAARAAoAAAABAAAAAAASAAoAAAABAAAAAAATAAoAAAABAAAAAAASAAwAAAABAAIAAAATAAwAAAABAAIAAAAUAAsAAAACAAEAAAAMAAsAAAABAAIAAAANAAsAAAABAAIAAAAOAAsAAAABAAIAAAAPAAsAAAABAAIAAAAQAAsAAAABAAIAAAAMAAoAAAABAAEAAAANAAoAAAABAAEAAAAOAAoAAAABAAEAAAARAAsAAAABAAEAAAASAAsAAAABAAEAAAATAAsAAAABAAEAAAA=")
 tile_set = SubResource("TileSet_pko0k")
 
-[node name="Bridge" type="TileMapLayer" parent="." node_paths=PackedStringArray("bellow_bridge_area", "on_bridge_area")]
+[node name="Bridge" type="TileMapLayer" parent="."]
 tile_map_data = PackedByteArray("AAAWAAsAAAAAAAAAAAAXAAsAAAABAAAAAAAYAAsAAAABAAAAAAAZAAsAAAABAAAAAAAaAAsAAAABAAAAAAAbAAsAAAABAAAAAAAcAAsAAAABAAAAAAAdAAsAAAABAAAAAAAeAAsAAAABAAAAAAAfAAsAAAABAAAAAAAgAAsAAAABAAAAAAAhAAsAAAABAAAAAAAiAAsAAAABAAAAAAAjAAsAAAABAAAAAAAkAAsAAAABAAAAAAAlAAsAAAABAAAAAAAmAAsAAAABAAAAAAAnAAsAAAABAAAAAAAoAAsAAAABAAAAAAApAAsAAAACAAAAAAA=")
 tile_set = SubResource("TileSet_3cg8g")
 collision_visibility_mode = 1
-script = ExtResource("11_pko0k")
-bellow_bridge_area = NodePath("BellowBridgeArea")
-on_bridge_area = NodePath("OnBridgeArea")
 
 [node name="OnBridgeArea" type="Area2D" parent="Bridge"]
 position = Vector2(1459, 730)
@@ -298,7 +294,7 @@ script = ExtResource("11_oe1b3")
 
 [node name="OnBridgeCollision" type="CollisionPolygon2D" parent="Bridge/OnBridgeArea"]
 position = Vector2(-13.6208, -5.48883)
-polygon = PackedVector2Array(-20, -20, 26, -20, 26, -5, 1180, -5, 1180, -20, 1230, -20, 1230, 50, 1180, 50, 1180, 26, 26, 26, 26, 50, -20, 50)
+polygon = PackedVector2Array(-12, -3, 1220, -3, 1220, 26, -12, 26)
 
 [node name="BellowBridgeArea" type="Area2D" parent="Bridge"]
 collision_layer = 128