java - Java 中的十字准线

Question

我正在制作一款需要十字准线的游戏。我一直在玩 java.awt.cursor 类，这很容易，但问题是我不希望十字准线能够离开我为游戏创建的窗口，所以我尝试了这个:

  private void drawCrossHair(Graphics g){
    Ellipse2D ellipse = new Ellipse2D.Float();
    ellipse.setFrame(crossHair.x, crossHair.y, 36, 36);
    Color yellow = new Color (0xEDFF62);
    g.setColor(yellow);            
    g.fillOval(crossHair.x, crossHair.y, 40, 40);
    g.setClip(ellipse);
    g.clip(ellipse);

基本上，我试图从“g”中删除“椭圆”，只留下一个小环。这里的问题是“g.clip(ellipse);”给我一个错误。我使用这段代码的目的是创建一个中心透明的圆，就像一个 donut 。创建 donut 后，我将在其内部添加一些小点，使其看起来更像十字准线。可能会或可能不会成为问题的一件事是，我计划使用操纵杆而不是鼠标来移动十字准线……我不知道这是否会限制我对十字准线可以是哪种对象的选择。

编辑:

这是一个 SSCCE 版本(好吧几乎...由于“g2 = bf.getDrawGraphics()”而无法编译)

package game;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Toolkit;
import java.awt.image.BufferStrategy;
import javax.swing.JFrame;
import java.awt.geom.Ellipse2D;

public class Game extends JFrame {

    private int windowWidth = 1280;
    private int windowHeight = 1024;
        private Ball crossHair;

    public static void main(String[] args) {
        new Game();
    }
    public Game() {
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setSize(windowWidth, windowHeight);
        this.setResizable(false);
        this.setLocation(0,0);
        this.setVisible(true);
        this.createBufferStrategy(2);
        initGame();
        gameLoop();
    }
    private void initGame() {
            crossHair = new Ball (windowWidth/2, windowHeight/2, 3, 3);
    }

        private void gameLoop() {
            //game logic
            drawFrame();              
        }

        private void drawFrame() {

            //Setting up Double Buffering
            BufferStrategy bf = this.getBufferStrategy();
            Graphics2D g2 = (Graphics2D)bf.getDrawGraphics();

            try {
                g2 = bf.getDrawGraphics();
                Color darkBlue = new Color(0x010040);

                g2.setColor(darkBlue);
                g2.fillRect(0, 0, windowWidth, windowHeight);

                drawCrossHair(g2);
            } finally {
                // dispose of graphic.
                g2.dispose();
            }

            // show contents of backbuffer on screen
            bf.show();

            Toolkit.getDefaultToolkit().sync();
        }

        private void drawCrossHair(Graphics2D g2){
            Color yellow = new Color (0xEDFF62);
            g2.setColor(yellow);            
            g2.fillOval(crossHair.x, crossHair.y, 40, 40);
            Ellipse2D ellipse = new Ellipse2D.Float();
            ellipse.setFrame(crossHair.x, crossHair.y, 36, 36);
            g2.setClip(ellipse);
            g2.clip(ellipse);
        }  
}

这是同一个包中的另一个类:

打包游戏；

public class Ball {
    public int x;
    public int y;
    public int dx;
    public int dy;

    public Ball(int x, int y, int dx, int dy) {
        this.x = x;
        this.y = y;
        this.dx = dx;
        this.dy = dy;
    }
}

编辑 2:

这是我最近的尝试，这似乎工作正常...如果这是错误的编码请告诉我(我知道了 here ):

private void drawCrossHair(Graphics g){
    Color yellow = new Color (0xEDFF62);
    g.setColor(yellow);
    for (int i = 0; i < 1; i++) {
    g.drawOval(crosshair.x + i, crosshair.y + i, 40 - i - i, 40 - i - i);
    }
    g.fillArc(crosshair.x + 10, crosshair.y + 21 , 20, 20, -45, -90);
    g.fillArc(crosshair.x - 1, crosshair.y + 10, 20, 20, -135, -90);
    g.fillArc(crosshair.x + 10, crosshair.y - 1, 20, 20, -225, -90);
    g.fillArc(crosshair.x + 21, crosshair.y + 10, 20, 20, -315, -90);
}

Answer 1

but the problem is that I do not want the crosshairs to be able to leave the window I create for my game,

事实并非如此。当鼠标移出框架或组件时，光标会重置。

再次，发布显示问题的 SSCCE。