override func viewDidLoad() {
    super.viewDidLoad()
    var danmuView: XDanMuView = XDanMuView()
    danmuView.frame = .init(x: 0, y: 100, width: self.view.frame.size.width, height: self.view.frame.size.height - 200)
    self.view.addSubview(danmuView)

    // 配置项
    danmuView.minSpeed = 1
    danmuView.maxSpeed = 2
    danmuView.gap = 20
    danmuView.lineHeight = 30

    // 启动弹幕
    danmuView.start()
    // 启动一个定时器灌弹幕
    timer = Timer.scheduledTimer(timeInterval: 0.4, target: self, selector: #selector(addDanMu), userInfo: nil, repeats: false)
}

@objc func addDanMu() {
    let interval = CGFloat.random(in: 0.3...1.0)
    Timer.scheduledTimer(timeInterval: interval, target: self, selector: #selector(addDanMu), userInfo: nil, repeats: false)
    
    var text = ""
    for _ in 0...Int.random(in: 1...30) {
        text += "嘿"
    }
    for _ in 0...Int.random(in: 1...2) {
        danmuView.addDanMu(text: text, isMe: Bool.random())
    }
}