//BounceBall.java
//Illustrates the animation loop with an image
//Andy Harris, 06/00

import java.awt.*;
import java.applet.*;

public class BounceBall extends Applet implements Runnable {

  int dx = 10;
  int dy = 10;
  int ballX = 0;
  int ballY = 0;
  
  Image imgBall;
  AudioClip sndBoing;
  
  Thread looper;
  boolean keepGoing = false;

  public void init(){
    imgBall = getImage(getCodeBase(), "ball.gif");
    sndBoing = getAudioClip(getCodeBase(), "boing.au");
  } // end if
  
  public void start(){
    if (looper == null){
      looper = new Thread(this);
      keepGoing = true;
      looper.start();
    } // end if
  } // end start

  public void stop(){
    keepGoing = false;
    looper = null;
  } // end stop

  public void run(){
    
    while (keepGoing){
      int appWidth = getSize().width;
      int appHeight = getSize().height;
      
      try {
        looper.sleep(100);
      } catch (InterruptedException exc){
        System.out.println(exc.getMessage());
      } // end try
  
      ballX += dx;
      ballY += dy;
  
      if (ballX > appWidth - imgBall.getWidth(this)){
	dx = -dx;
	sndBoing.play();
      } // end if

      if (ballX < 0){
	dx = -dx;
	sndBoing.play();
      } // end if

      if (ballY > appHeight - imgBall.getHeight(this)){
	dy = -dy;
	sndBoing.play();
      } // end if

      if (ballY < 0){
	dy = - dy;
	sndBoing.play();
      } // end if

      repaint();
    } // end while
  } // end run

  public void paint(Graphics g){
    g.drawImage(imgBall, ballX, ballY, this);
  } // end paint

} // end class def