add random start for train o start from a stop

core/biome_generator/rails.gd

@@ -47,15 +47,112 @@ var next_stop_index: int = 0
 var stop_multiply: float = 1.0
 var is_restarting: bool = false
 var tween_restart: Tween
+var environment_config: EnvironmentConfig
 
 func _ready() -> void:
+	_cache_environment_config()
 	if curve != null and curve.get_baked_length() > 0:
 		build_rails()
 		build_train()
 		_plan_stops()
+		_apply_initial_train_start()
 	else:
 		print("WARNING: Draw Path3D for rails!")
 
+func _cache_environment_config() -> void:
+	var parent_node: Node = get_parent()
+	if parent_node != null:
+		var day_night_node := parent_node.get_node_or_null("DayNight") as EnvironmentManagerRoot
+		if day_night_node != null:
+			environment_config = day_night_node.environment_config
+			return
+
+	var current_scene: Node = get_tree().current_scene
+	if current_scene == null:
+		return
+
+	for child in current_scene.get_children():
+		var environment_manager := child as EnvironmentManagerRoot
+		if environment_manager != null:
+			environment_config = environment_manager.environment_config
+			return
+
+func _apply_initial_train_start() -> void:
+	if train_instance == null or curve == null:
+		return
+
+	var total_length: float = curve.get_baked_length()
+	if total_length <= 0.0:
+		return
+
+	#start from a random position
+	if environment_config != null and environment_config.train_start_from_random_position:
+		train_progress = randf() * total_length
+		_update_next_stop_index_from_progress()
+	elif environment_config != null and not stop_offset.is_empty():
+		#start from a specific stop
+		var stop_index: int = clampi(environment_config.train_start_stop_index, 0, stop_offset.size() - 1)
+		train_progress = stop_offset[stop_index]
+		_set_next_stop_index_from_current(stop_index)
+	else:
+		train_progress = wrapf(train_progress, 0.0, total_length)
+		_update_next_stop_index_from_progress()
+
+	_snap_train_to_progress()
+
+func _set_next_stop_index_from_current(current_stop_index: int) -> void:
+	if stop_offset.is_empty():
+		next_stop_index = 0
+		return
+
+	if train_speed >= 0.0:
+		next_stop_index = (current_stop_index + 1) % stop_offset.size()
+	else:
+		next_stop_index = current_stop_index - 1
+		if next_stop_index < 0:
+			next_stop_index = stop_offset.size() - 1
+
+func _update_next_stop_index_from_progress() -> void:
+	if stop_offset.is_empty():
+		next_stop_index = 0
+		return
+
+	if train_speed >= 0.0:
+		next_stop_index = 0
+		for i in range(stop_offset.size()):
+			if stop_offset[i] > train_progress + 0.001:
+				next_stop_index = i
+				return
+		return
+
+	next_stop_index = stop_offset.size() - 1
+	for i in range(stop_offset.size() - 1, -1, -1):
+		if stop_offset[i] < train_progress - 0.001:
+			next_stop_index = i
+			return
+
+func _snap_train_to_progress() -> void:
+	if train_instance == null or curve == null:
+		return
+
+	var total_length: float = curve.get_baked_length()
+	if total_length <= 0.0:
+		return
+
+	train_progress = wrapf(train_progress, 0.0, total_length)
+	var center_position: Vector3 = to_global(curve.sample_baked(train_progress, true))
+	var prog_forward: float = wrapf(train_progress + 2.0, 0.0, total_length)
+	var forward_position: Vector3 = to_global(curve.sample_baked(prog_forward, true))
+
+	train_instance.global_position = center_position
+	if center_position.distance_to(forward_position) > 0.01:
+		train_instance.look_at(forward_position, Vector3.UP)
+		train_instance.rotate_y(PI)
+
+	if cameras:
+		cameras.global_position = center_position
+		cameras.global_basis = train_instance.global_basis
+
 func build_rails() -> void:
 	var mat_wood = StandardMaterial3D.new()
 	mat_wood.albedo_color = Color(0.35, 0.2, 0.1)