fix

core/biome_generator/biome_generator.gd

@@ -25,32 +25,32 @@ const RIVER_NEIGHBOUR_OFFSETS: Dictionary = {
 }
 
 @export_group("Rails")
-@export var rail_path: Path3D 
+@export var rail_path: Path3D #rail path
 
 @export_group("Biomes")
-@export var biome_list: Array[Biome]
+@export var biome_list: Array[Biome] #list of scenes for the biome
 
 @export_group("Grid and Area")
-@export var chunk_size: float = 20.0
-@export var eye_line: int = 3 
-@export var district_scale: float = 0.05 
+@export var chunk_size: float = 20.0	#size of a cell; default 20 (global position is defined dividing x and z for this value) 
+@export var eye_line: int = 3 #cells to be considerated around the train (e.g. 3 => a square of cells from -3 to 3 around train cell)
+@export var district_scale: float = 0.05 #noise value to distribuite biome; low values create large area, high values create biome with more variants
 
 @export_group("Lamppost")
 @export var lamppost_wire_material: ShaderMaterial 
 @export_range(0.01, 1.0) var wire_thickness: float = 0.05
-@export var lamppost_dist_factor: int = 10
+@export var lamppost_dist_factor: int = 10 #max distance of connections
 
 var board: Dictionary = {}
 var last_pos_train: Vector2i = Vector2i(999999, 999999) 
 var noise_generator: FastNoiseLite 
 var altitude_generator: FastNoiseLite
 var wire_connections: Dictionary = {}
-var chunk_candidate_cache: Dictionary = {}
+var chunk_candidate_cache: Dictionary = {} #node cache (metadata)
 var pending_generation_cells: Array[Vector2i] = []
 var pending_cleanup_cells: Array[Vector2i] = []
 var pending_wire_cells: Array[Vector2i] = []
 var pending_wire_lookup: Dictionary = {}
-var rail_chunk_catalogue: Dictionary = {}
+var rail_chunk_catalogue: Dictionary = {} #rails chunk list
 
 var manual_biome: Biome = null
 
@@ -59,7 +59,8 @@ func _ready() -> void:
 
 	#connect events
 	UIEvents.update_rail_chunks.connect(_update_rail_chunks)
-		
+	
+	#noise generator for biome and altitute
 	noise_generator = FastNoiseLite.new()
 	noise_generator.noise_type = FastNoiseLite.TYPE_PERLIN
 	noise_generator.seed = randi() 
@@ -70,8 +71,10 @@ func _ready() -> void:
 	altitude_generator.seed = randi() 
 	altitude_generator.frequency = district_scale * 0.5 
 	
+	#fill cache with available chunk
 	_warm_chunk_candidate_cache()
 	_warm_rail_chunk_catalogue()
+	#set unique pieces
 	_update_set_pieces()
 
 func _update_set_pieces() -> void:
@@ -128,6 +131,7 @@ func _destroy_and_regenrate_world() -> void:
 		_refresh_world(current_pos)
 
 func _process(_delta: float) -> void:
+	#based on constant values the queue are evalutated by frame and not all together
 	_drain_cleanup_queue()
 	_drain_generation_queue()
 	_drain_wire_queue()
@@ -153,6 +157,15 @@ func collect_all_chunkinfo(root: Node, list: Array[Node]) -> void:
 	for child in root.get_children():
 		collect_all_chunkinfo(child, list)
 
+func collect_all_propinfo(root: Node, list: Array[Node]) -> void:
+	if root == null: return
+
+	if "available_props" in root:
+		list.append(root)
+
+	for child in root.get_children():
+		collect_all_propinfo(child, list)
+
 func _warm_chunk_candidate_cache() -> void:
 	var unique_scenes: Dictionary = {}
 
@@ -514,6 +527,30 @@ func _pick_backup_scene(zone_catalogue: Array[PackedScene], grid_pos: Vector2i)
 			return scene
 	return zone_catalogue[0]
 
+func _spawn_props_for_chunk(root: Node) -> void:
+	var prop_markers: Array[Node] = []
+	collect_all_propinfo(root, prop_markers)
+
+	for marker in prop_markers:
+		_spawn_prop_for_marker(marker)
+
+func _spawn_prop_for_marker(marker: Node) -> void:
+	if marker.available_props.is_empty():
+		return
+
+	var prop_scene = marker.available_props.pick_random()
+	if prop_scene == null:
+		return
+
+	var prop_instance = prop_scene.instantiate()
+	var prop_node = prop_instance as Node3D
+	if prop_node == null:
+		prop_instance.queue_free()
+		return
+
+	marker.add_child(prop_node)
+	prop_node.transform = Transform3D.IDENTITY
+
 func _register_cell_with_ray(grid_pos: Vector2i) -> bool:
 	if board.has(grid_pos): return true 
 	
@@ -681,6 +718,7 @@ func _add_compatible_biome(grid_pos: Vector2i) -> void:
 		new_chunk.position = Vector3(grid_pos.x * chunk_size, 0, grid_pos.y * chunk_size)
 		new_chunk.rotation.y = choise.rotation * (-PI / 2.0)
 		add_child(new_chunk)
+		_spawn_props_for_chunk(new_chunk)
 		
 		var info_new = _get_cached_chunk_info(new_chunk, choise.scene)
 		
@@ -711,6 +749,7 @@ func _add_compatible_biome(grid_pos: Vector2i) -> void:
 		var backup = backup_scene.instantiate()
 		backup.position = Vector3(grid_pos.x * chunk_size, 0, grid_pos.y * chunk_size)
 		add_child(backup)
+		_spawn_props_for_chunk(backup)
 		
 		var info_backup = _get_cached_chunk_info(backup, backup_scene)
 		var backup_uniqueness = _get_chunk_uniqueness_from_info(info_backup)

core/biome_generator/prop_info.gd

@@ -0,0 +1,4 @@
+extends Marker3D
+class_name PropInfo
+
+@export var available_props: Array[PackedScene]

core/biome_generator/prop_info.gd.uid

@@ -0,0 +1 @@
+uid://dg6ngy4pmtsyc