Question

我只需要在鼠标点击图像时移动图像。

我有这个动作：

if (Mouse.GetState().LeftButton == ButtonState.Pressed &&
    previousMouseState.LeftButton != ButtonState.Pressed)
{
    xpos = rnd.Next(windowWidth - texture.Width);
    ypos = rnd.Next(windowHeight - texture.Height);
}

previousMouseState = Mouse.GetState();

但我需要某种复合if逻辑才能使它只有在点击纹理时才会移动。

Answer 1

我认为您的texture对象不仅仅是Texture2D。

绘制精灵时，你既有位置又有大小。这样的事情应该有效：

var currentMouseState = Mouse.GetState();

if (currentMouseState.LeftButton == ButtonState.Pressed &&
previousMouseState.LeftButton != ButtonState.Pressed)
{
    Vector2 mousePosition = new Vector2(currentMouseState.X,currentMouseState.Y);

    mousePosition-=sprite.Position;

    /// .Bounds is a property of Texture2D, and returns a Rectangle() struct
    var spriteWasClicked = sprite.Bounds.Contains(mousePosition.X,mousePosition.Y);

    if(spriteWasClicked)
    {
        xpos = rnd.Next(windowWidth - texture.Width);
        ypos = rnd.Next(windowHeight - texture.Height);

        // update sprite position with to xpos,ypos here.
    }

}

previousMouseState = currentMouseState;

Answer 2

我认为Reactive Extensions对此非常适合。

您上面的代码可能是基于触发事件的计时器/调度程序调用的。您可以通过调用IObservable<T>将其更改为Observable.FromEvent method实施。

完成后，您可以使用IObservable<T>上的LINQ operators来获取鼠标按下之间的“窗口”。您很可能会像TakeUntil method这样使用：

// Your initial observable.
var timerObservable = Observable.FromEvent(timer, "TimerFired");

// The button pressed.
var pressed = timerObservable.
    Where(t => Mouse.GetState().LeftButton == ButtonState.Pressed);

// The button not pressed.
var notPressed = timer.Observable.
    Where(t => Mouse.GetState().LeftButton != ButtonState.Pressed);

// Observe the not pressed until it is pressed.
// Make sure to repeat.
var pressed = notPressed.SkipUntil(pressed).Repeat();

然后你可以调用Subscribe method并传递一个代表，代码将在按下按钮时被调用。

您甚至可以通过拨打Observable.Timer method来更换计时器，以生成您正在等待的计时器。

在C＃XNA游戏中通过鼠标单击移动图像

2 个答案: