如果之前的视图控制器不是根视图控制器，也没有导航控制器，我如何从SKScene访问它？

guard let window = UIApplication.shared.windows.first,
      let rootViewController = window.rootViewController else {
    return
}

var currentViewController = rootViewController
while let presentedViewController = currentViewController.presentedViewController {
    currentViewController = presentedViewController
}

if let previousViewController = currentViewController.presentingViewController {
    // 在这里可以访问到之前的视图控制器
}

if let scene = self.scene as? YourSKSceneClass {
    scene.previousViewController = previousViewController
}