Missile Command- HELP!

Question

I'm writing a missile command program for a class. I need help getting the enemy missiles(the ones that shoot down towards the city) to recognize the user's missiles and terminate. This seems especially hard since the users missiles are ellipses and not rectanges and the Ellipse2D.Double's I use use bounding boxes. Let me know if you have any ideas (I tried the contains method, didn't really know how it works)
Thanks!
Borismeister
import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.awt.geom.Ellipse2D;
import java.lang.Thread;
import javax.swing.JOptionPane;
public class Screen extends Applet
public void init()
MyListener listener = new MyListener();
addMouseListener(listener);
level = 2;
threads = new ArrayList(level * 10);
shot = 0;
for(int i = 0; i < level * 10; i++)
threads.add(new LaserThread(1, this));
LaserThread p = (LaserThread)threads.get(i);
p.start();
missiles = new ArrayList();
public void paint(Graphics g)
Graphics2D g2 = (Graphics2D)g;
// tryInterrupt();
// public void tryInterrupt()
// for(int i = 0; i < missiles.size() + 1; i++)
// MissileThread mis = (MissileThread)missiles.get(i);
// Missile mos = mis.getMissile();
// for(int j = 0; j < threads.size() + 1; j ++)
// LaserThread thr = (LaserThread)threads.get(j);
// Ellipse2D.Double circ = (Ellipse2D.Double)mos.getEllipse();
// if (circ.getX() > thr.getX())
// thr.interrupt();
private int shots = 20;
Applet a = this;
private ArrayList threads;
private int level;
public static int shot;
public static ArrayList missiles;
class MyListener implements MouseListener
public void mouseClicked(MouseEvent e) {}
public void mousePressed(MouseEvent e)
MissileThread mt = new MissileThread(e.getX(), e.getY(), a, threads);
mt.start();
missiles.add(mt);
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
import java.applet.Applet;
import java.awt.Graphics2D;
import java.util.Random;
import javax.swing.JOptionPane;
import java.awt.geom.Ellipse2D;
A thread that moves a car
The car will run into the wall without stopping.
public class LaserThread extends Thread
Constructs a with a given top left corner
@param x the x coordinate of the top left corner
@param y the y coordinate of the top left corner
@param speed the speed of the car
public LaserThread(int aSpeed, Applet anApplet)
speed = 15 - aSpeed;
a = anApplet;
private int toWait;
public void run()
Random gen = new Random();
try
sleep(gen.nextInt(3000));
shot = new Laser(1, a);
}catch(InterruptedException e) {}
try
while(true)
shot.advance( (Graphics2D)a.getGraphics() );
sleep(speed);
catch (InterruptedException e)//SEX!!!!
public int getX()
return shot.getX();
public int getY()
return shot.getY();
private double dx;
private Applet a;
private int speed; //lower values mean faster
private Laser shot;
import java.util.Random;
import java.applet.Applet;
import java.awt.Graphics2D;
import java.awt.geom.Ellipse2D;
import java.util.ArrayList;
public class Laser
public Laser(int aLevel, Applet a)
Random generator = new Random();
target = generator.nextInt(a.getWidth());
xStart = generator.nextInt(a.getWidth());
slope = (0-a.getHeight())/(xStart - target);
public void advance(Graphics2D g2)
y++;
x = (int)((y + slope * xStart)/slope);
g2.fill(new Ellipse2D.Double(x, y, 2, 2));
public int getX()
return x;
public int getY()
return y;
private int level; //reflects the speed
private int target; // 0 - getWidth(), thus not all will actually hit targets
private int speed; //initialized based on the level
private int xStart;
private int xEnd;
private int downSteps;
private int sideSteps;
private double slope;
private int x, y;
import java.applet.Applet;
import java.awt.Graphics2D;
import java.util.Random;
import java.awt.geom.Ellipse2D;
import java.util.ArrayList;
A thread that moves a car
The car will run into the wall without stopping.
public class MissileThread extends Thread
public MissileThread(int myX, int myY, Applet anApplet, ArrayList threads)
x = myX;
y = myY;
a = anApplet;
private int x, y;
private Applet a;
private Missile myMissile;
public void run()
myMissile = new Missile(x, y, a);
myMissile.shoot();
public Object getCirc()
return myMissile.getEllipse();
public Missile getMissile()
return myMissile;
import java.awt.geom.Ellipse2D;
import java.lang.Thread;
import java.applet.Applet;
import java.awt.Graphics2D;
import java.awt.Color;
public class Missile
public Missile(int myX, int myY, Applet anApp)
x = myX;
y = myY;
a = anApp;
private Applet a;
private int x, y;
public int getX()
return x;
public int getY()
return y;
public Ellipse2D.Double getEllipse()
return circ;
public void shoot()
int myX = x;
int myY = y;
Graphics2D g2 = (Graphics2D)a.getGraphics();
for(int i = 0; i < 60; i++)
circ = new Ellipse2D.Double(myX, myY, 2 * i, 2 * i);
g2.fill(circ);
myX--;
myY--;
try
Thread.sleep(40);
catch(InterruptedException e) {}
g2.setColor(Color.white);
g2.fill(circ);
Ellipse2D.Double circ;
}

Answer 1

the Ellipse2D.Double class has an intersects method, so use it on the adversary's missiles to see if you should terminate.