Question

我不明白为什么在我超过球的前半部分后，当我控制的球击中移动球的右半部分时，它不会激活碰撞代码来杀死程序。

我将它设置为测量你控制的球与经过的球之间的距离。我仍然感到困惑，为什么我可以在没有程序自行结束的情况下降落在球的后半段。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.image.BufferedImage;

import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import java.awt.event.ActionListener;
import java.awt.event.KeyListener;
import javax.swing.ImageIcon;

public class JumpingSprite extends JPanel implements KeyListener {

 //public int yPos;

public static void main(String[] args) {
    new JumpingSprite();
}




public JumpingSprite() {


    EventQueue.invokeLater(new Runnable() {
        @Override
        public void run() {



            try {
                             UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
            } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
            }

            JFrame frame = new JFrame("Mr.Baird");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setLayout(new BorderLayout());
            TestPane testPane = new TestPane();
            frame.add(testPane);
            frame.pack();
            frame.setLocationRelativeTo(null);
            frame.setVisible(true);







        }
    });
}

public  class TestPane extends JPanel {

    int getyPos(){

        return yPos;

    }

    protected static final int SPRITE_HEIGHT = 60;
    protected static final int SPRITE_WIDTH = 60;
    private float vDelta; 
    private float rbDelta; 
    private float rbDegDelta; 
    public int yPos; 
    private float gDelta; // Gravity
    private Timer engine;
    private boolean bounce = false;

    int ballx = 1000;
    int bally = 500;
    int ballw = 100;
    int ballh = 100;

    int ball2x = 1500;
    int ball2y = 480;
    int ball2w = 120;
    int ball2h = 120;

    int ball3x = 2500;
    int ball3y = 0;
    int ball3w = 600;
    int ball3h = 600;
    public TestPane() {

        yPos = getPreferredSize().height - SPRITE_HEIGHT;
        vDelta = 0;
        gDelta = 3f;
        rbDegDelta = 30f; //affects how many bounces mang

        InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
        ActionMap am = getActionMap();
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0), "jump");
        am.put("jump", new AbstractAction() {
            @Override
            public void actionPerformed(ActionEvent e) {


                if (yPos + SPRITE_HEIGHT == getHeight()) {
                    vDelta = -40        ;
                    rbDelta = vDelta;
                    bounce = true;
                }
            }
        });

        engine = new Timer(15, new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                int height = getHeight();


                if (height > 0) {

                    if (bounce) {

                        yPos += vDelta;

                        vDelta += gDelta;
                        // If the sprite is not on the ground
                        if (yPos + SPRITE_HEIGHT >= height) {
                            // put on le ground
                            yPos = height - SPRITE_HEIGHT;

                            if (rbDelta >= 0) {
                                // Stop bouncin
                                bounce = false;
                            } else {
                                // Add the re-bound degregation delta to the re-bound delta
                                rbDelta += rbDegDelta;
                                // Set the vDelta...
                                vDelta = rbDelta;
                            }
                        }
                    }
                }
  if (Math.sqrt((Math.pow((500 - (ballx)), 2)) +                   Math.pow((yPos - bally), 2)) <= (50)) {
                    System.exit(0);
                }
                if (Math.sqrt((Math.pow((500 - (ball2x)), 2)) + Math.pow((yPos - ball2y), 2)) <= (60)) {
                    System.exit(0);
                }
                if (Math.sqrt((Math.pow((500 - (ball3x)), 2)) + Math.pow((yPos - ball3y), 2)) <= (350)) {
                    System.exit(0);
                }


                ballx = ballx-8;
                ball2x = ball2x-8;
                ball3x = ball3x-8;
                repaint();


            }
        });
        engine.start();
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(1000, 600);
    }

    @Override
    protected void paintComponent(Graphics g) {
        //addin all them pretty colors to le object
        super.paintComponent(g);
        //Graphics2D g2d = (Graphics2D) g.create();
        g.setColor(Color.black);
        g.fillRect(0,0,1000,1000);
        int width = getWidth() - 1;
        int xPos = (width - SPRITE_WIDTH) / 2;
        g.setColor(Color.blue);
        g.fillOval(xPos, yPos, SPRITE_WIDTH, SPRITE_HEIGHT);
        //g.dispose();


        g.setColor(Color.red);
        g.fillOval(ballx, bally, ballw, ballh);

        g.setColor(Color.green);
        g.fillOval(ball2x, ball2y, ball2w, ball2h);

        g.setColor(Color.pink);
        g.fillOval(ball3x, ball3y, ball3w, ball3h);
    }





}

@Override
public void keyPressed(KeyEvent arg0) {
    // TODO Auto-generated method stub

}

@Override
public void keyReleased(KeyEvent arg0) {
    // TODO Auto-generated method stub

}

@Override
public void keyTyped(KeyEvent arg0) {
    // TODO Auto-generated method stub

}

}

Answer 1

该问题的一般解决方案是计算两个球/圆的中心之间的（欧几里德）距离，并确定该长度是否小于它们的组合半径。另一种方法是从java.awt.Area创建Shape，然后使用Area.intersect(Area)！= null;

球碰撞问题，只有一半球碰撞

1 个答案: