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

public class AnimationTwoThread extends Applet {

//----------------------------------------------------
/** Sequence through an array of 15 images to perform
 *  the anmimation. A seperate Thread controls each
 *  tumbling Duke. The Applet's stop method calls a
 *  public service of the Duke class to terminate
 *  the thread. Override update to avoid flicker
 *  problems.
 */

  private static final int NUMIMAGES = 15;
  private static final int NUMDUKES  = 2;
  private Image[] images;
  private Duke[]  dukes;


  public void init() {
    dukes = new Duke[NUMDUKES];
    images = new Image[ NUMIMAGES ];
    for (int i=0; i<NUMIMAGES; i++)
      images[i] = getImage(getCodeBase(),
                           "images/T" + i + ".gif");
    setBackground(Color.white);
  }

  //--------------------------------------------------
  /** Start each thread, specifing a direction to
   *  sequence through the array of images.
   */
  public void start() {
    int tumbleDirection = 1;        
    for (int i=0; i<NUMDUKES ; i++) {
      if (i%2 == 1) tumbleDirection = -1;
        dukes[i] = new Duke(tumbleDirection, 
                               NUMIMAGES, this);
      dukes[i].start();
    }
  }

  //----------------------------------------------------
  /** Skip the usual screen-clearing step of update
   *  so that there is no "flicker" between each 
   *  drawing step.
   */
  public void update(Graphics g) {
    paint(g);
  }
    
  public void paint(Graphics g) {
    if (dukes[0] != null)
      g.drawImage(images[ dukes[0].getIndex() ],
                                          0, 0, this);
    if (dukes[1] != null)
      g.drawImage(images[ dukes[1].getIndex() ],
                                        200, 0, this);
  }

  //----------------------------------------------------
  /** When the Applet's stop method is called, use the
   *  public service, setState, of the Duke class
   *  to set a flag and terminate run method of the 
   *  thread.
   */
  public void stop() {
    for (int i=0; i<NUMDUKES ; i++) 
      if (dukes[i] != null)
        dukes[i].setState(Duke.STOP);
  }
}