Lab6

// 2110101 : Lab6 (2545)
// dept. of computer engineering
// Chulalongkorn Univ.
import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class XBall1 extends Applet implements Runnable {
  Thread ballThread;
  double x, y, dx, dy;
  int radius;
  
  public void run() {
    int frameWidth, frameHeight;
    setBallProperties();
    
    // add your local variable declarations here
    
    while (ballThread == Thread.currentThread()) {
      frameWidth = getSize().width;
      frameHeight = getSize().height;
      // add your code here
      // (x, y) is the ball's position
      // (dx, dy) is the velocity vector
      // frameWidth and frameWidth are width and height of the bounding frame.
      //
      // The following code makes the ball bouncing inside the frame
      // forever with no gravity and no loss of energy
      if (x <= radius || x >= frameWidth - radius) dx = -dx;
      if (y <= radius || y >= frameHeight - radius) dy = -dy;
      else dy+= 1;
         
      x += dx;
      y += dy;

      repaint();    // paint the screen
      try {         // wait for 30msec
        Thread.sleep(30);
      } catch (InterruptedException e) {}
    }

  } // end of run method
 
  public void init() {
    this.addMouseListener(new java.awt.event.MouseAdapter() {
      public void mouseClicked(MouseEvent e) {
        this_mouseClicked(e);
      }
    });
  }

  void this_mouseClicked(MouseEvent e) {
    this.stop();
    this.start();
  }
    
  public void start() {
    ballThread = new Thread(this);
    ballThread.start();
  }
  public void stop() {
    ballThread = null;
  }

  private void setBallProperties() {
    radius = 5 + (int) (15 * Math.random());
    x = radius + (int) ((getSize().width - 2 * radius) * Math.random());
    y = radius + 1 + (int) (50 * Math.random());
    dx = 1 + (2 * Math.random());
    dy = 1 + (2 * Math.random());
    if (Math.random() < 0.5) dx = -dx;
  }

  public void paint(Graphics g) {
    g.setColor(Color.black);
    g.fillOval((int) x - radius, (int) y - radius, 2 * radius, 2 * radius);
  }

  // main method
  public static void main(String[] args) {
    Frame frame = new Frame("XBall1");
    XBall1 applet = new XBall1();

    frame.addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
          System.exit(0);
        }
      }
    );
    frame.add(applet, BorderLayout.CENTER);
    frame.setSize(200, 200);
    frame.setVisible(true);
    applet.init();
    applet.start();
  }
}

// 2110101 : Lab6 (2545)
// dept. of computer engineering
// Chulalongkorn Univ.
import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class XBall2 extends Applet implements Runnable {
  Thread ballThread;
  double x, y, dx, dy;
  int radius;
  
  public void run() {
    int frameWidth, frameHeight;
    setBallProperties();
    
    // add your local variable declarations here
    
    while (ballThread == Thread.currentThread()) {
      frameWidth = getSize().width;
      frameHeight = getSize().height;
      // add your code here
      // (x, y) is the ball's position
      // (dx, dy) is the velocity vector
      // frameWidth and frameWidth are width and height of the bounding frame.
      //
      // The following code makes the ball bouncing inside the frame
      // forever with no gravity and no loss of energy
            
      if (x <= radius || x >= frameWidth - radius) dx = -dx;
      if (y <= radius || y >= frameHeight - radius) dy = -dy;
      if (y < frameHeight - radius) dy = dy + 1;
      x += dx;
      y += dy;
      double le = 0.95;
      if (x <= radius || x >= frameWidth - radius) dx = -dx;
      if (y <= radius || y >= frameHeight - radius) {
        dy = -dy *.8;
        dx = dx;
      } else dy+= 9.8*0.3;


      repaint();    // paint the screen
      try {         // wait for 30msec
        Thread.sleep(30);
      } catch (InterruptedException e) {}
    }

  } // end of run method
 
  public void init() {
    this.addMouseListener(new java.awt.event.MouseAdapter() {
      public void mouseClicked(MouseEvent e) {
        this_mouseClicked(e);
      }
    });
  }

  void this_mouseClicked(MouseEvent e) {
    this.stop();
    this.start();
  }
    
  public void start() {
    ballThread = new Thread(this);
    ballThread.start();
  }
  public void stop() {
    ballThread = null;
  }

  private void setBallProperties() {
    radius = 5 + (int) (15 * Math.random());
    x = radius + (int) ((getSize().width - 2 * radius) * Math.random());
    y = radius + 1 + (int) (50 * Math.random());
    dx = 1 + (2 * Math.random());
    dy = 1 + (2 * Math.random());
    if (Math.random() < 0.5) dx = -dx;
  }

  public void paint(Graphics g) {
    g.setColor(Color.black);
    g.fillOval((int) x - radius, (int) y - radius, 2 * radius, 2 * radius);
  }

  // main method
  public static void main(String[] args) {
    Frame frame = new Frame("XBall2");
    XBall2 applet = new XBall2();

    frame.addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
          System.exit(0);
        }
      }
    );
    frame.add(applet, BorderLayout.CENTER);
    frame.setSize(200, 200);
    frame.setVisible(true);
    applet.init();
    applet.start();
  }
}