void 
FlipLevelTransformer::transform_platform(float height, Platform& platform)
{
  Path& path = platform.get_path();
  for (std::vector<Path::Node>::iterator i = path.nodes.begin(); i != path.nodes.end(); i++) {
    Vector& pos = i->position;
    pos.y = height - pos.y - platform.get_bbox().get_height();
  }
}
void
FlipLevelTransformer::transform_platform(float height, Platform& platform)
{
  transform_path(height, platform.get_bbox().get_height(), platform.get_path());
}