XNA / Monogame 如何检测鼠标何时悬停在按钮上

Question

我目前正在学习编程，并且正在制作一个单人游戏的小游戏。但是，我的进度在菜单上停止了，我正在尝试找出如何检测我的鼠标是否在按钮上方，但我无法弄清楚如何使用精灵进行检查？

class Menubutton
{
    public Texture2D texture;
    public Vector2 coords;
    bool isClicked = false;
    bool isHovered = false;

    public Menubutton(Texture2D textur, int X, int Y)
    {
        this.texture = textur;
        this.coords.X = X;
        this.coords.Y = Y;
    }

    public void Update(GameWindow window)
    {


    }

    public void Draw(SpriteBatch spriteBatch)
    {
        spriteBatch.Draw(texture, coords, Color.White);
    }
}

}

Answer 1

这样的事情应该可以解决问题：

public void Update(GameWindow window)
{
    var mouseState = Mouse.GetState();
    var mousePoint = new Point(mouseState.X, mouseState.Y);
    var rectangle = new Rectangle(mousePoint.X, mousePoint.Y, this.texture.Width, this.texture.Height);

    if (rectangle.Contains(mousePoint))
    {
        isHovered = true;
        isClicked = mouseState.LeftButton == ButtonState.Pressed;
    }
    else
    {
        isHovered = false;
        isClicked = false;
    }
}

请注意，isClicked 标志实际含义的定义可能会有所不同。在这个简单的实现中，它只是意味着在按钮上方按下鼠标按钮，但从技术上讲，这并不是真正的“点击”，所以如果你想要比这更复杂的东西，我会让你自己考虑。

Answer 2

我通常将尽可能多的 Input 逻辑分离到一个静态 InputManager 类中：

public static class InputManager
{
    // #region #endregion tags are a nice way of blockifying code in VS.
    #region Fields

    // Store current and previous states for comparison. 
    private static MouseState previousMouseState;
    private static MouseState currentMouseState;

    // Some keyboard states for later use.
    private static KeyboardState previousKeyboardState;
    private static KeyboardState currentKeyboardState;

    #endregion



    #region Update

    // Update the states so that they contain the right data.
    public static void Update()
    {
        previousMouseState = currentMouseState;
        currentMouseState = Mouse.GetState();

        previousKeyboardState = currentKeyboardState;
        currentKeyboardState = Keyboard.GetState();
    }

    #endregion



    #region Mouse Methods

    public static Rectangle GetMouseBounds(bool currentState)
    {
        // Return a 1x1 squre representing the mouse click's bounding box.
        if (currentState)
            return new Rectangle(currentMouseState.X, currentMouseState.Y, 1, 1);
        else
            return new Rectangle(previousMouseState.X, previousMouseState.Y, 1, 1);
    }

    public static bool GetIsMouseButtonUp(MouseButton btn, bool currentState)
    {
        // Simply returns whether the button state is released or not.

        if (currentState)
            switch (btn)
            {
                case MouseButton.Left:
                    return currentMouseState.LeftButton == ButtonState.Released;
                case MouseButton.Middle:
                    return currentMouseState.MiddleButton == ButtonState.Released;
                case MouseButton.Right:
                    return currentMouseState.RightButton == ButtonState.Released;
            }
        else
            switch (btn)
            {
                case MouseButton.Left:
                    return previousMouseState.LeftButton == ButtonState.Released;
                case MouseButton.Middle:
                    return previousMouseState.MiddleButton == ButtonState.Released;
                case MouseButton.Right:
                    return previousMouseState.RightButton == ButtonState.Released;
            }

        return false;
    }

    public static bool GetIsMouseButtonDown(MouseButton btn, bool currentState)
    {
        // This will just call the method above and negate.
        return !GetIsMouseButtonUp(btn, currentState);
    }

    #endregion



    #region Keyboard Methods

    // TODO: Keyboard input stuff goes here.

    #endregion
}

// A simple enum for any mouse buttons - could just pass mouseState.ButtonState instead 
public enum MouseButton
{
    Left,
    Middle,
    Right
}

您的 MenuButton 类可能看起来像这样：

public class MenuButton
{
    #region Properties

    // Some properties that might come is handy
    public Rectangle Bounds { get { return bounds; } }

    public MenuButtonState State { get { return currentState; } }

    // Redundant but handy
    public bool IsClicked { get { return currentState == MenuButtonState.Clicked; } }

    #endregion



    #region Fields

    private Texture2D texture;
    private Vector2 position;
    private Rectangle bounds;

    private MenuButtonState currentState;

    #endregion



    #region Constructor

    public MenuButton(Texture2D texture, Vector2 position)
    {
        this.texture = texture;
        this.position = position;
        // Cast position X and Y to ints for the rectangle's constructor.
        bounds = new Rectangle((int)position.X, (int)position.Y, texture.Width, texture.Height);

        // MenuButton starts off as Released.
        currentState = MenuButtonState.Released;
    }

    #endregion



    #region Update

    public void Update()
    {
        // There are much better ways to impliment button interaction than this 
        // but here is a simple example:

        // If the mouse cursor is on our MenuButton...
        if (InputManager.GetMouseBounds(true).Intersects(bounds))
        {
            // And if the Left mouse button is down...
            if (InputManager.GetIsMouseButtonDown(MouseButton.Left, true))
            {
                // Then our MenuButton is down!
                currentState = MenuButtonState.Pressed;
            }
            // Else if the Left mouse button WAS down but isn't any more...
            else if (InputManager.GetIsMouseButtonDown(MouseButton.Left, false))
            {
                // Then our MenuButton has been clicked!
                currentState = MenuButtonState.Clicked;
            }
            // Otherwise...
            else
            {
                // The mouse cursor is simply hovering above our MenuButton!
                currentState = MenuButtonState.Hovered;
            }
        }
        else
        {
            // If the cursor does not intersect with the MenuButton then just set the state to released.
            currentState = MenuButtonState.Released;
        }
    }

    #endregion
}

public enum MenuButtonState
{
    Released,
    Hovered,
    Pressed,
    Clicked
}

当然你会有一个 Draw() 函数，可能还有其他一些函数。

我没有测试过上面的代码，但主要是希望它能帮助你到达你想要的地方。我在尝试实现与按钮交互的不同方式时获得了很多乐趣。例如，当按钮被按住时能够处理点击，然后光标移开，然后移回按钮，然后释放。