java简单实现桌球滚动效果

package pers.javacode.lzw.ballgame;

import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;

import javax.swing.JFrame;

public class BallGame extends JFrame {
 //加载图片
 Image ball=Toolkit.getDefaultToolkit().getImage("images/ball.png");
 Image desk=Toolkit.getDefaultToolkit().getImage("images/desk.jpg");
 
 public void frameLunch()
 {
 this.setSize(856,500);
 this.setLocation(50,50);
 this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 this.setVisible(true);
 while(true)
 {
 repaint();
 try {
 Thread.sleep(40);
 } catch (InterruptedException e) {
 
 e.printStackTrace();
 }
 }
 
 }
 double x=100;
 double y=100;
 double degree=3.14/4;//对应的是60度
 public void paint(Graphics g)
 {
 
 g.drawImage(desk,0,0,null);
 g.drawImage(ball,(int)x,(int)y,null);
 //创建动态的小球滚动的状态
 x = (x+ 10*Math.cos(degree));
  y = y +10*Math.sin(degree); 
  
  //碰到上下边界
  if(y>500-40-30||y<40+40){//500是窗口高度；40是桌子边框，30是球直径；最后一个40是标题栏的高度
  degree = -degree;
  }
  
  //碰到左右边界
  if(x<40||x>856-40-30){
  degree = 3.14 - degree;
  }
 
 
 }
 public static void main(String[] args) {
 BallGame ba=new BallGame();
 ba.setTitle("Ball Game");
 ba.frameLunch();
 }

 
}