Question

在Monogame（c＃）中，我无法弄清楚如何保持一个物体（在这种情况下是一个汉堡）留在游戏窗口的边界内，这样它就不会在光标移动时离开游戏窗口。或者换句话说，将一个对象“夹住”到游戏窗口。

    public class Burger
{
    #region Fields

    // graphic and drawing info
    Texture2D sprite;
    Rectangle drawRectangle;

    // burger stats
    int health = 100;

    // shooting support
    bool canShoot = true;
    int elapsedCooldownMilliseconds = 0;

    // sound effect
    SoundEffect shootSound;

    #endregion

    #region Constructors

    /// <summary>
    ///  Constructs a burger
    /// </summary>
    /// <param name="contentManager">the content manager for loading content</param>
    /// <param name="spriteName">the sprite name</param>
    /// <param name="x">the x location of the center of the burger</param>
    /// <param name="y">the y location of the center of the burger</param>
    /// <param name="shootSound">the sound the burger plays when shooting</param>
    public Burger(ContentManager contentManager, string spriteName, int x, int y,
        SoundEffect shootSound)
    {
        LoadContent(contentManager, spriteName, x, y);
        this.shootSound = shootSound;
    }

    #endregion

    #region Properties

    /// <summary>
    /// Gets the collision rectangle for the burger
    /// </summary>
    public Rectangle CollisionRectangle
    {
        get { return drawRectangle; }
    }

    #endregion

    #region Public methods

    /// <summary>
    /// Updates the burger's location based on mouse. Also fires 
    /// french fries as appropriate
    /// </summary>
    /// <param name="gameTime">game time</param>
    /// <param name="mouse">the current state of the mouse</param>
    public void Update(GameTime gameTime, MouseState mouse)
    {
        // burger should only respond to input if it still has health

        // move burger using mouse
        if (health > 0)
        {
            drawRectangle.X = mouse.X;
            drawRectangle.Y = mouse.Y;

        }

        // clamp burger in window

        [THIS IS WHERE THE CODE SHOULD GO]

        // update shooting allowed
        // timer concept (for animations) introduced in Chapter 7

        // shoot if appropriate

    }

    /// <summary>
    /// Draws the burger
    /// </summary>
    /// <param name="spriteBatch">the sprite batch to use</param>
    public void Draw(SpriteBatch spriteBatch)
    {
        spriteBatch.Draw(sprite, drawRectangle, Color.CornflowerBlue);
    }

    #endregion

    #region Private methods

    /// <summary>
    /// Loads the content for the burger
    /// </summary>
    /// <param name="contentManager">the content manager to use</param>
    /// <param name="spriteName">the name of the sprite for the burger</param>
    /// <param name="x">the x location of the center of the burger</param>
    /// <param name="y">the y location of the center of the burger</param>
    private void LoadContent(ContentManager contentManager, string spriteName,
        int x, int y)
    {
        // load content and set remainder of draw rectangle
        sprite = contentManager.Load<Texture2D>(spriteName);
        drawRectangle = new Rectangle(x - sprite.Width / 2,
            y - sprite.Height / 2, sprite.Width,
            sprite.Height);
    }

    #endregion
}

我有什么想法可以解决这个问题？我已经尝试过使用mouse.Getstate并尝试将鼠标光标锁定到窗口，但这似乎不起作用。

Answer 1

问题似乎是你正在控制你汉堡课程内的坐标（很好的问题）而且你似乎没有任何对窗口边界的引用。

我看到它的方式是你有两个选择：

选项1.它不错，但在较大的项目中，它可能会适得其反的项目阶段：

public void Update(GameTime gameTime, MouseState mouse)
{
    if (health > 0)
    {
        //Simple version
        //if mouse is within borders, continue with position update.
        if(mouse.X > 0 && mouse.X < windowWidth && mouse.Y > 0 && mouse.Y < windowHeight){
           drawRectangle.X = mouse.X;
           drawRectangle.Y = mouse.Y;
        }else{
           //stuff to do if it it's not updating   
        }

        //a little different (better) version that should trace walls
        if(mouse.X < 0){
           drawRectangle.X = 0;
        }else if(mouse.X + drawRectangle.width > windowWidth){ //if I made no mistakes it should subtract the size of the picture and trace the inside border if mouse is outside
           drawRectangle.X = windowWidth - drawRectangle.width;
        }else{
           drawRectangle.X = mouse.X
        }
        if(mouse.Y < 0){
           drawRectangle.Y = 0;
        }else if(mouse.Y + drawRectangle.height > windowHeight ){
           drawRectangle.Y = windowHeight - drawRectangle.height;
        }else{
           drawRectangle.Y = mouse.Y
        }
    }

}

当鼠标位于边框之外时，选项2限制主更新功能中的更新调用：

class YourApp{
   ....
   public void Update(GameTime gameTime, MouseState mouse)
    {
         if([mouse is within the window]){
            burger.Update(...);
            //+most of your updates here
         }else{
            //pause game or just display a warning that mouse is outside of the window
         }
    }
    ...
}

Answer 2

当您为drawRectangle的X和Y属性赋值时，您应该执行Min和Max函数以确保其位置在窗口内。

drawRectangle.X = Math.Min(Math.Max(mouse.X, 0), GraphicsDevice.Viewport.Width);
drawRectangle.Y = Math.Min(Math.Max(mouse.Y, 0), GraphicsDevice.Viewport.Height);

如果你想让精灵完全受限，你必须考虑精灵/矩形自身的高度和宽度（假设X和Y位置是矩形的左上角，我可以＆＃ 39;记住XNA的矩形是否与System.Drawing中的矩形不同。

drawRectangle.X = Math.Min(Math.Max(mouse.X, 0), (GraphicsDevice.Viewport.Width - drawRectangle.Width));
drawRectangle.Y = Math.Min(Math.Max(mouse.Y, 0), (GraphicsDevice.Viewport.Height - drawRectangle.Height));

Answer 3

您可以使用MathHelper.Clamp()进行裁剪，使用GraphicsDevice.Viewport作为屏幕尺寸：

public void Update(GameTime gameTime, MouseState mouse)
{
    if (health > 0)
    {
        drawRectangle.X = (int) MathHelper.Clamp(mouse.X, 0, 
                  GraphicsDevice.Viewport.Width - drawRectangle.Width);
        drawRectangle.Y = (int) MathHelper.Clamp(mouse.Y, 0,
                  GraphicsDevice.Viewport.Height - drawRectangle.Height);
    }
    // ...
}

C＃将对象粘贴到窗口？

3 个答案: