}
void
-Dart::activate()
+Dart::initialize()
{
physic.set_velocity_x(dir == LEFT ? -::SPEED : ::SPEED);
sprite->set_action(dir == LEFT ? "flying-left" : "flying-right");
+}
+void
+Dart::activate()
+{
sound_source.reset(sound_manager->create_sound_source(SOUNDFILE));
sound_source->set_position(get_pos());
sound_source->set_looping(true);