add scenes

core/biome_generator/biome_generator.gd

@@ -1,8 +1,13 @@
 extends Node3D
 
+const CHUNK_TYPE_BIOME: int = 0
+const CHUNK_TYPE_STRAIGHT_TRACK: int = 1
+const CHUNK_TYPE_CURVED_TRACK: int = 2
+
 const CHUNK_GENERATION_STEPS_PER_FRAME: int = 2
 const CHUNK_CLEANUP_STEPS_PER_FRAME: int = 4
 const LAMPPOST_WIRE_STEPS_PER_FRAME: int = 1
+const RAILWAY_SCENE_DIRECTORY: String = "res://tgcc/chunk/railway/scene"
 
 @export_group("Rails")
 @export var rail_path: Path3D 
@@ -31,11 +36,15 @@ var pending_cleanup_cells: Array[Vector2i] = []
 var pending_wire_cells: Array[Vector2i] = []
 var pending_wire_lookup: Dictionary = {}
 var pending_radar_update: bool = false
+var rail_chunk_catalogue: Dictionary = {}
 
 var manual_biome: Biome = null
 
 func _ready() -> void:
 	if biome_list.is_empty() or rail_path == null: return
+
+	#connect events
+	UIEvents.update_rail_chunks.connect(_update_rail_chunks)
 		
 	noise_generator = FastNoiseLite.new()
 	noise_generator.noise_type = FastNoiseLite.TYPE_PERLIN
@@ -48,6 +57,7 @@ func _ready() -> void:
 	altitude_generator.frequency = district_scale * 0.5 
 	
 	_warm_chunk_candidate_cache()
+	_warm_rail_chunk_catalogue()
 	_update_set_pieces()
 
 func _update_set_pieces() -> void:
@@ -154,6 +164,28 @@ func _warm_chunk_candidate_cache() -> void:
 	for scene in unique_scenes.values():
 		_get_chunk_scene_metadata(scene)
 
+func _warm_rail_chunk_catalogue() -> void:
+	rail_chunk_catalogue.clear()
+
+	var directory := DirAccess.open(RAILWAY_SCENE_DIRECTORY)
+	if directory == null:
+		return
+
+	directory.list_dir_begin()
+	var file_name := directory.get_next()
+	while file_name != "":
+		if not directory.current_is_dir() and file_name.ends_with(".tscn"):
+			var scene_path := "%s/%s" % [RAILWAY_SCENE_DIRECTORY, file_name]
+			var scene := load(scene_path) as PackedScene
+			if scene != null:
+				var chunk_type = _get_chunk_type_from_scene(scene)
+				if chunk_type == CHUNK_TYPE_STRAIGHT_TRACK or chunk_type == CHUNK_TYPE_CURVED_TRACK:
+					if not rail_chunk_catalogue.has(chunk_type):
+						rail_chunk_catalogue[chunk_type] = []
+					rail_chunk_catalogue[chunk_type].append(scene)
+		file_name = directory.get_next()
+	directory.list_dir_end()
+
 func _get_chunk_scene_cache_key(scene: PackedScene) -> String:
 	if scene == null:
 		return ""
@@ -209,6 +241,20 @@ func _get_cached_chunk_info(instance: Node, scene: PackedScene) -> Node:
 		return instance
 	return instance.get_node_or_null(info_path)
 
+func _get_chunk_type_from_scene(scene: PackedScene) -> int:
+	if scene == null:
+		return CHUNK_TYPE_BIOME
+
+	var preview_chunk = scene.instantiate()
+	var info_list: Array[Node] = []
+	collect_all_chunkinfo(preview_chunk, info_list)
+	var info_node = info_list[0] if info_list.size() > 0 else null
+	var chunk_type = CHUNK_TYPE_BIOME
+	if info_node != null and "chunk_type" in info_node:
+		chunk_type = info_node.chunk_type
+	preview_chunk.queue_free()
+	return chunk_type
+
 func _clear_pending_world_work() -> void:
 	pending_generation_cells.clear()
 	pending_cleanup_cells.clear()
@@ -216,6 +262,94 @@ func _clear_pending_world_work() -> void:
 	pending_wire_lookup.clear()
 	pending_radar_update = false
 
+func _collect_replaceable_rail_chunks(root: Node, result: Array[Node3D]) -> void:
+	if root == null:
+		return
+
+	if root is Node3D:
+		var node_3d := root as Node3D
+		if node_3d.scene_file_path.begins_with(RAILWAY_SCENE_DIRECTORY):
+			var info_list: Array[Node] = []
+			collect_all_chunkinfo(node_3d, info_list)
+			var info_node = info_list[0] if info_list.size() > 0 else null
+			if info_node != null and "chunk_type" in info_node:
+				var chunk_type = info_node.chunk_type
+				if chunk_type == CHUNK_TYPE_STRAIGHT_TRACK or chunk_type == CHUNK_TYPE_CURVED_TRACK:
+					result.append(node_3d)
+					return
+
+	for child in root.get_children():
+		_collect_replaceable_rail_chunks(child, result)
+
+func _pick_replacement_rail_scene(chunk_type: int, current_scene_path: String) -> PackedScene:
+	var candidates: Array = rail_chunk_catalogue.get(chunk_type, [])
+	if candidates.is_empty():
+		return null
+
+	var alternatives: Array[PackedScene] = []
+	for candidate in candidates:
+		var scene := candidate as PackedScene
+		if scene != null and scene.resource_path != current_scene_path:
+			alternatives.append(scene)
+
+	if not alternatives.is_empty():
+		return alternatives.pick_random()
+	return candidates.pick_random() as PackedScene
+
+func _replace_rail_chunk_instance(chunk_root: Node3D) -> bool:
+	if chunk_root == null or not is_instance_valid(chunk_root):
+		return false
+
+	var info_list: Array[Node] = []
+	collect_all_chunkinfo(chunk_root, info_list)
+	var info_node = info_list[0] if info_list.size() > 0 else null
+	if info_node == null or not "chunk_type" in info_node:
+		return false
+
+	var replacement_scene = _pick_replacement_rail_scene(info_node.chunk_type, chunk_root.scene_file_path)
+	if replacement_scene == null:
+		return false
+
+	var chunk_parent = chunk_root.get_parent()
+	var replacement = replacement_scene.instantiate() as Node3D
+	if chunk_parent == null or replacement == null:
+		return false
+
+	var chunk_index = chunk_root.get_index()
+	var chunk_name = chunk_root.name
+	chunk_root.name = "%s_old" % chunk_name
+
+	replacement.transform = chunk_root.transform
+	chunk_parent.add_child(replacement)
+	chunk_parent.move_child(replacement, chunk_index)
+	replacement.name = chunk_name
+	replacement.owner = chunk_root.owner
+	chunk_root.queue_free()
+	return true
+
+func _refresh_rail_chunks() -> void:
+	print("update rail chunks")
+	_warm_rail_chunk_catalogue()
+
+	var current_scene: Node = get_tree().current_scene
+	if current_scene == null:
+		return
+
+	var replaceable_chunks: Array[Node3D] = []
+	_collect_replaceable_rail_chunks(current_scene, replaceable_chunks)
+
+	var replaced_count = 0
+	for chunk_root in replaceable_chunks:
+		if _replace_rail_chunk_instance(chunk_root):
+			replaced_count += 1
+
+	if replaced_count > 0:
+		await get_tree().process_frame
+		_destroy_and_regenrate_world()
+
+func _update_rail_chunks() -> void:
+	call_deferred("_refresh_rail_chunks")
+
 func _refresh_world(center: Vector2i) -> void:
 	_rebuild_generation_queue(center)
 	_rebuild_cleanup_queue(center)

core/ui_events.gd

@@ -30,6 +30,10 @@ signal toggle_shadows(value: bool)
 @warning_ignore("unused_signal")
 signal toggle_fog(value: bool)
 
+#railway signals
+@warning_ignore("unused_signal")
+signal update_rail_chunks()
+
 #day cycle signals
 @warning_ignore("unused_signal")
 signal toggle_pause_daytime(value: bool)