//Drifter - a modified Java Applet
//Clay Graham

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

public class Drifter extends java.applet.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 init() {
  resize(500,500);              // Set bubble window size
}

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*(int)Math.random(), y + (int)(Math.sqrt( r*r - ( (i+x)*(i-x) ))));
    g.drawLine(y,i,y*(int)Math.random() * 255,i);
    g.fillRect(y,i,(int)Math.random()*25,(int)Math.random()*20);
 }
}

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*(int)Math.random()*10 - ( (i-x)*(i-x) ))));
  }
  for (i=x-r; i<=x+r; i++) {     // Draws the lower edge of the circle

    //g.setColor(Color.lightGray);
    Color c = new java.awt.Color((int)Math.random()*255,(int)Math.random()*255,(int)Math.random()*255);
    g.setColor(c);
    g.drawLine(i, y + (int)(Math.sqrt( r*r*(int)Math.random()*10 - ( (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]=550;
    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], 25), g);
    if (bubble < MAXBUBBLES) {
      bubble++; thisbubble++;
    }
    else
      thisbubble = MAXBUBBLES;
  }
  for (i=0; i<bubble; i++) {
    if (i%5 <= stepper) { // Steps each bubble at a different speed
      record[i][1] -= 1;
      move_bubble(record[i][0], record[i][1], record[i][2], 
                  new java.awt.Color(record[i][3], record[i][4], 255), 1, g);
      for (j=0; j<i; j++) {   // Checks for touching bubbles, pops one
        tmp = ( (record[i][1]-record[j][1])*(record[i][1]-record[j][1]) +
                (record[i][0]-record[j][0])*(record[i][0]-record[j][0]) );
        if (j != i && Math.sqrt(tmp) < record[i][2] + record[j][2]) {
          for (tmp = record[i][2]; tmp >= -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()*12);
  }
}

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

public void start() {
  if (artist == null) {
    artist = new Thread(this);
    artist.start();
  }
}

public void stop() {
    artist = null;
}
public void run() {
  while (artist != null) {
    try {Thread.sleep(100);} catch (InterruptedException e){}
    repaint();
  }
  artist = null;
}
}