Question

我正在开发一款2D赛车游戏。这是XNA游戏的截图; http://oi41.tinypic.com/vxhy5y.jpg。我想知道如何创建一个计时器。因此，例如，“如果car1blue / car2red与方格旗启动计时器碰撞，如果它们再次发生碰撞，则停止计时器。”这会在理论上起作用吗？如果它在理论上有用，我该如何在XNA中进行？

如果你愿意，我可以提供我迄今为止所做的代码。

非常感谢！

EDIT; 是否有可能告诉我代码在哪里？

Answer 1

如果不知道如何将它们放在一起，你能不能只在它们通过线路的某个时间存储一个DateTime，所以当它开始时你会这样做：

public MyGame
{
    DateTime lastLapTimestamp = DateTime.Now;
    TimeSpan lastLapTime = new TimeSpan();
    // other stuff

    public void Update(TimeSpan elapsedTime)
    {
        if(HasCompletedLap)
        {
            var currentLapTimestamp = DateTime.Now;
            lastLapTime = currentLapTimestamp - lastLapTimestamp;
            lastLapTimestamp = currentLaptimeStamp;
        }
        // Other stuff
    }
}

然后只需显示你的lastLapTime，无论你想看看它需要多长时间。

Answer 2

这里要求的是您的示例空XNA项目中需要的实现，我再次回答您在上面提出的关于单圈时间的问题：

/* 
    NEW MEMBERS FOR YOU TO IMAGINE YOU HAVE SOME MEANINGFUL RACING GAME 
*/
private Vector2 yourPosition;
private Texture2D yourCar;
private Texture2D yourTrack;
private Rectangle yourStartingLine;

private DateTime currentLapTimestamp = DateTime.Now();
private TimeSpan currentLapTime = new TimeSpan();

public Game1()
{
    graphics = new GraphicsDeviceManager(this);
    Content.RootDirectory = "Content";
}

protected override void Initialize()
{
    // Put your starting line somewhere
    yourStartingLine = new Rectangle(100,100,10,100)

    base.Initialize();  
}

protected override void LoadContent()
{
    yourCar = Content.Load<Texture2D>("YourCarAssetName")
    yourTrack = Content.Load<Texture2D>("YourTrackAssetName")
}

protected override void UnloadContent()
{
    // TODO: Unload any non ContentManager content here
}

protected override void Update(GameTime gameTime)
{
    // Check your keyboard input
    UpdatePosition(Keyboard.GetState());
    if(HasPassedStartingLine())
    { UpdateLapTime(); }
    base.Update(gameTime);
}

protected override void Draw(GameTime gameTime)
{
    GraphicsDevice.Clear(Color.CornflowerBlue);
    DrawTrack();
    DrawCar();
    DrawLapTime();
    base.Draw(gameTime);
}

/* 
    NEW METHODS FOR YOU TO PRETEND DO STUFF
*/  

private void UpdateLapTime()
{
    var newTimestamp = DateTime.Now;
    currentLapTime = newTimestamp - currentLapTimestamp;
}

private bool HasPassedStartingLine()
{
    // Work out if you have passed the starting line
    // and make sure you dont register it again until
    // they have passed the finish line
}

private void UpdatePosition(KeyboardState keyboardState)
{
    // Assumes you work out how to handle your players
    // controls to move the position of the car
}

private void DrawTrack()
{
    // Your rendering logic for the track
}

private void DrawCar()
{
    // Your rendering logic for the car
}

private void DrawLapTime()
{
    // your rendering logic for the lap time
}

如何在XNA中添加一个计时器？

2 个答案: