[Bubbles!] by Rachel Gollub

// author: Rachel Gollub, 1995
// Bubbles!

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

public class test004 extends Applet implements Runnable {
  Thread artist=null;
  int bubble=0, thisbubble=0;   // # of bubbles on screen, and current bubble
  int MAXBUBBLES = 25;           // Maximum bubbles on screen
  int stepper = 4;               // Counter for which bubbles to move when
  int record[][] = new int[MAXBUBBLES][5];  // Array that holds bubbles
  
public void draw_bubble(int x, int y, int r, Color col, Graphics g) {
  int i;
  for (i=x-r; i<=x+r; i++) {     // Draws a circle
    g.setColor(col);
    g.drawLine(i, y - (int)(Math.sqrt( r*r - ( (i-x)*(i-x) ))),
               i, y + (int)(Math.sqrt( r*r - ( (i-x)*(i-x) ))));
  }
}

public void move_bubble(int x, int y, int r, Color col, int step, Graphics g) {
  int i;
  for (i=x-r; i<=x+r; i++) {     // Draws the upper edge of a circle
    g.setColor(col);
    g.drawLine(i, y - (int)(Math.sqrt( r*r - ( (i-x)*(i-x) ))),
               i, y + step - (int)(Math.sqrt( r*r - ( (i-x)*(i-x) ))));
  }
  for (i=x-r; i<=x+r; i++) {     // Draws the lower edge of the circle
    g.setColor(Color.black);
    g.drawLine(i, y + (int)(Math.sqrt( r*r - ( (i-x)*(i-x) ))),
               i, y + step + (int)(Math.sqrt( r*r - ( (i-x)*(i-x) ))));
  }
}

public void paint(Graphics g) {
  int i, j, tmp;
  if (bubble < MAXBUBBLES || thisbubble < MAXBUBBLES) {    
    record[thisbubble][0]=(int)(Math.random() * 500);
    record[thisbubble][1]=230;
    record[thisbubble][2]=(int)(Math.random() * 500)/20;
    record[thisbubble][3]=(int)(Math.random() * 255);
    record[thisbubble][4]=(int)(Math.random() * 255);
    draw_bubble(record[thisbubble][0],record[thisbubble][1],
                record[thisbubble][2],new java.awt.Color(record[thisbubble][3],
                                               record[thisbubble][4], 255), g);
    if (bubble < MAXBUBBLES) {
      bubble++; thisbubble++;
    }
    else
      thisbubble = MAXBUBBLES;
  }
  for (i=0; i= -1; tmp = tmp - 2)
            draw_bubble(record[i][0], record[i][1], record[i][2]-tmp,
                        Color.lightGray, g);
          draw_bubble(record[j][0], record[j][1], record[j][2], 
                      new java.awt.Color(record[j][3], record[j][4], 255), g);
          record[i][1] = -1; record[i][2]=0;
        }
      }
    }
    if (record[i][1]+record[i][2] < 0 && bubble >= MAXBUBBLES) {
      thisbubble = i;
    }
    stepper=(int)(Math.random()*10);
  }
}

public void update(Graphics g) {
  paint(g);
}

public void start() {
  setBackground(Color.black);
  artist = new Thread(this);
  artist.start();
}

public void stop() {
    artist = null;
}

public void run() {
  while (artist != null) {
    try {Thread.sleep(50);} catch (InterruptedException e){}
    repaint();
  }
  artist = null;
}
}