add uniqueness par for props

core/biome_generator/biome_generator.gd

@@ -46,6 +46,7 @@ var noise_generator: FastNoiseLite
 var altitude_generator: FastNoiseLite
 var wire_connections: Dictionary = {}
 var chunk_candidate_cache: Dictionary = {} #node cache (metadata)
+var prop_candidate_cache: Dictionary = {}
 var pending_generation_cells: Array[Vector2i] = []
 var pending_cleanup_cells: Array[Vector2i] = []
 var pending_wire_cells: Array[Vector2i] = []
@@ -89,7 +90,7 @@ func _update_set_pieces() -> void:
 
 		var local_biome = ""
 		if manual_biome != null:
-			local_biome = manual_biome.nome
+			local_biome = manual_biome.name
 		else:
 			var grid_x = roundi(sp.global_position.x / chunk_size)
 			var grid_z = roundi(sp.global_position.z / chunk_size)
@@ -115,7 +116,7 @@ func _destroy_and_regenrate_world() -> void:
 	#Destroy all models
 	for pos in board.keys():
 		var cella = board[pos]
-		if cella["type"] != "obstacle":
+		if not _is_persistent_obstacle(cella):
 			if cella.has("node") and is_instance_valid(cella["node"]):
 				cella["node"].queue_free()
 				
@@ -349,6 +350,8 @@ func _replace_rail_chunk_instance(chunk_root: Node3D) -> bool:
 	chunk_root.queue_free()
 	return true
 
+#rebuild the scene catalogue from res://tgcc/chunk/railway/scene,
+#than serach on the current scene which chunks can be changed and for each one chose a new scene (the same kind)
 func _refresh_rail_chunks() -> void:
 	print("update rail chunks")
 	_warm_rail_chunk_catalogue()
@@ -376,6 +379,9 @@ func _refresh_world(center: Vector2i) -> void:
 	_rebuild_generation_queue(center)
 	_rebuild_cleanup_queue(center)
 
+#check cells around the train by rings:
+#first the center, then borders with distance = 1, the distance = 2 and so to eye_line.
+#Use maxi(abs(x), abs(z)) to know the border of the ring. Cells closest to the train have more priority
 func _rebuild_generation_queue(center: Vector2i) -> void:
 	pending_generation_cells.clear()
 
@@ -390,13 +396,16 @@ func _rebuild_generation_queue(center: Vector2i) -> void:
 					continue
 				pending_generation_cells.append(grid_pos)
 
+#For each cells add to cleanup queue the cells too far
+#Use eye_line plus a margin value to hide chunks not instantly when go out of the eye line
+#Persistent obstacle cells are not deleted (rails or set_pieces)
 func _rebuild_cleanup_queue(center: Vector2i) -> void:
 	pending_cleanup_cells.clear()
 	var safe_margin = 2
 
 	for grid_pos in board.keys():
 		var cell = board[grid_pos]
-		if cell["type"] == "obstacle":
+		if _is_persistent_obstacle(cell):
 			continue
 
 		var dist_x = abs(grid_pos.x - center.x)
@@ -424,7 +433,7 @@ func _drain_cleanup_queue() -> void:
 			continue
 
 		var cell = board[grid_pos]
-		if cell["type"] == "obstacle":
+		if _is_persistent_obstacle(cell):
 			continue
 
 		if cell.has("node") and is_instance_valid(cell["node"]):
@@ -462,6 +471,8 @@ func _generate_pieces_around_train(center: Vector2i) -> void:
 				if not ce_obstacle:
 					_add_compatible_biome(grid_pos)
 
+#Decice which catalogue of chunks use for a cell. If manual_biome is set use always it
+#Otherwise read noise_generator.get_noise_2d to give an index for biome_list
 func _choose_catalogue_by_cell(grid_pos: Vector2i) -> Array[PackedScene]:
 	if manual_biome != null:
 		return manual_biome.available_chunks
@@ -484,6 +495,14 @@ func _get_chunk_uniqueness_from_info(info_node: Node) -> int:
 		return clampi(info_node.uniqueness, 0, MAX_CHUNK_UNIQUENESS)
 	return 0
 
+func _get_prop_uniqueness_from_info(info_node: Node) -> int:
+	if info_node != null and "uniqueness" in info_node:
+		return clampi(info_node.uniqueness, 0, MAX_CHUNK_UNIQUENESS)
+	return -1
+
+func _is_persistent_obstacle(cell: Dictionary) -> bool:
+	return cell.get("type", "") == "obstacle" and cell.get("persistent", true)
+
 func _has_nearby_unique_chunk(grid_pos: Vector2i, uniqueness: int) -> bool:
 	if uniqueness <= 0:
 		return false
@@ -527,6 +546,61 @@ func _pick_backup_scene(zone_catalogue: Array[PackedScene], grid_pos: Vector2i)
 			return scene
 	return zone_catalogue[0]
 
+func _get_prop_scene_cache_key(scene: PackedScene) -> String:
+	if scene == null:
+		return ""
+	if scene.resource_path != "":
+		return scene.resource_path
+	return "prop_scene_%s" % scene.get_instance_id()
+
+func _get_prop_scene_uniqueness(scene: PackedScene) -> int:
+	if scene == null:
+		return -1
+
+	var key = _get_prop_scene_cache_key(scene)
+	if prop_candidate_cache.has(key):
+		return prop_candidate_cache[key]
+
+	var preview_prop = scene.instantiate()
+	var uniqueness = _get_prop_uniqueness_from_info(preview_prop)
+	if uniqueness == -1:
+		var prop_info_list: Array[Node] = []
+		collect_all_propinfo(preview_prop, prop_info_list)
+		if not prop_info_list.is_empty():
+			uniqueness = _get_prop_uniqueness_from_info(prop_info_list[0])
+	preview_prop.queue_free()
+
+	prop_candidate_cache[key] = uniqueness
+	return uniqueness
+
+func _get_marker_prop_uniqueness(marker: Node) -> int:
+	var uniqueness = _get_prop_uniqueness_from_info(marker)
+	if uniqueness == -1:
+		return 0
+	return uniqueness
+
+func _pick_weighted_prop_scene(marker: Node) -> PackedScene:
+	var candidates = []
+	var fallback_uniqueness = _get_marker_prop_uniqueness(marker)
+
+	for prop_scene in marker.available_props:
+		if prop_scene == null:
+			continue
+
+		var uniqueness = _get_prop_scene_uniqueness(prop_scene)
+		if uniqueness == -1:
+			uniqueness = fallback_uniqueness
+
+		candidates.append({
+			"scene": prop_scene,
+			"weight": _get_uniqueness_pick_weight(uniqueness),
+			"uniqueness": uniqueness
+		})
+
+	if candidates.is_empty():
+		return null
+	return _pick_weighted_candidate(candidates).scene
+
 func _spawn_props_for_chunk(root: Node) -> void:
 	var prop_markers: Array[Node] = []
 	collect_all_propinfo(root, prop_markers)
@@ -538,7 +612,7 @@ func _spawn_prop_for_marker(marker: Node) -> void:
 	if marker.available_props.is_empty():
 		return
 
-	var prop_scene = marker.available_props.pick_random()
+	var prop_scene = _pick_weighted_prop_scene(marker)
 	if prop_scene == null:
 		return
 
@@ -551,6 +625,8 @@ func _spawn_prop_for_marker(marker: Node) -> void:
 	marker.add_child(prop_node)
 	prop_node.transform = Transform3D.IDENTITY
 
+#Using a vertical raycast from the top to the bottom at the center of the cell
+#If there is a collision search for a new chunk node
 func _register_cell_with_ray(grid_pos: Vector2i) -> bool:
 	if board.has(grid_pos): return true 
 	
@@ -623,7 +699,8 @@ func _register_cell_with_ray(grid_pos: Vector2i) -> bool:
 			"node": root_chunk,  
 			"info": right_info_node,     
 			"have_lamppost": have_lamppost,
-			"uniqueness": uniqueness
+			"uniqueness": uniqueness,
+			"persistent": true
 		}
 		
 		if have_lamppost:
@@ -632,6 +709,11 @@ func _register_cell_with_ray(grid_pos: Vector2i) -> bool:
 		return true 
 	return false 
 
+#For the cell to fill check the contrains for the four neighbors:
+#If the neighbor at north have and exit on south then new chunk should have exit to north (the same for east and ovest)
+#Contrains: 1 -> connection is mandatory; 0 -> no connection; -1 -> no contrain because there is no neighbor or it already exits
+#When generator know the contrains take all chunks and try all different rotations
+#A candidate is valid only if all contrains are correct
 func _add_compatible_biome(grid_pos: Vector2i) -> void:
 	var req_conn_north = _needed_connection(grid_pos + Vector2i(0, -1), "south")
 	var req_conn_est = _needed_connection(grid_pos + Vector2i(1, 0), "west")
@@ -730,7 +812,7 @@ func _add_compatible_biome(grid_pos: Vector2i) -> void:
 		_apply_river_flow_direction(new_chunk, river_flow_direction)
 			
 		board[grid_pos] = {
-			"type": "bioma", 
+			"type": "biome", 
 			"exit": choise.data["connections"], 
 			"river_exit": choise.data["river_connections"],
 			"river_flow_direction": river_flow_direction,
@@ -772,6 +854,8 @@ func _add_compatible_biome(grid_pos: Vector2i) -> void:
 			"uniqueness": backup_uniqueness
 		}
 
+#Check if a neighbors have a river direction: if yes try to continue it,
+#otherwise create a direction based on connections
 func _calculate_river_flow_direction(grid_pos: Vector2i, river_connections: Dictionary) -> Vector2:
 	var connected_sides: Array[String] = []
 	for side in RIVER_SIDE_ORDER:
@@ -1006,7 +1090,7 @@ func _connect_lamppost_wires(new_board_pos: Vector2i) -> void:
 		if not wire_connections.has(closest_id): wire_connections[closest_id] = 0
 		wire_connections[closest_id] += 1
 
-#draw lamppost
+#draw lamppost wires
 func _draw_parable(p1: Vector3, p2: Vector3, parent: Node3D) -> void:
 	var segments = 15
 	var lowering = 1.5 

core/biome_generator/prop_info.gd

@@ -2,3 +2,4 @@ extends Marker3D
 class_name PropInfo
 
 @export var available_props: Array[PackedScene]
+@export_range(0, 5, 1) var uniqueness: int = 0 #0=common; 5=unique