Bumper car simulation

Question

Hi!
I haven't yet started to code because I don't know where to begin. I have to produce a bumper car simulation consisted of a frame and two circles moving inside, bouncing off walls and each other. The question is: how to make the circles(bumper cars) move and how to make them bounce off walls and each other? Their initial position will be randomized inside the bordered panel and the two cars would have the same speeds (I believe that would be the simplest solution). Perhaps I could use the timer and refresh the Ellipse2D.Double object every 0.1 seconds? And find the method that would check when the cars areas would overlap to change the velocity relative to the position of the other object? Even if I manage to code that, the walls are still the problem.
In addition, perhaps user could enter the number of cars inside the frame but that is still SF for now.
Thanks,
Slaven

Answer 1

import javax.swing.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class Homework extends JFrame {
     private JLabel imageLabel;
     private byte[] image = { 71, 73, 70, 56, 55, 97, 48, 0, 48, 0, -58, 0, 0, 0, 0, 0, 111, 62, 0,
                     37, 20, 0, -118, 77, 0, -87, -87, -87, 119, 67, 1, 81, 45, 0, -95, -95,
                     -95, -97, -97, -97, -99, -99, -99, -103, -103, -103, 51, 28, 0, -109,
                     -109, -109, 41, 23, 0, -117, -117, -117, 78, 63, 46, -125, -125, -125,
                     121, 121, 121, 65, 36, 0, 113, 113, 113, 109, 109, 109, 107, 107, 107,
                     127, 124, 120, 109, 61, 0, 99, 99, 99, 97, 97, 97, -123, 127, 119, 87,
                     87, 87, 101, 88, 71, 22, 12, 0, 81, 81, 81, 77, 77, 77, 81, 48, 5, 123,
                     69, 0, 69, 69, 69, -10, -10, -10, 67, 67, 67, -14, -14, -14, -18, -18,
                     -18, 59, 59, 59, -20, -20, -20, 9, 5, 0, -22, -22, -22, -26, -26, -26,
                     36, 20, 0, 51, 51, 51, -28, -28, -28, -38, -38, -38, 80, 45, 0, 6, 3,
                     0, 117, 65, 0, 107, 60, 0, -46, -46, -46, -50, -50, -50, 27, 27, 27,
                     -52, -52, -52, -56, -56, -56, -58, -58, -58, 93, 56, 9, 13, 13, 13, -68,
                     -68, -68, 94, 53, 0, -125, 73, 0, -74, -74, -74, -80, -80, -80, -82, -82,
                     -82, -84, -84, -84, 17, 9, 0, -90, -90, -90, 7, 4, 0, 44, 24, 0, 68, 55,
                     40, -102, -102, -102, -108, -108, -108, -110, -110, -110, 91, 73, 49,
                     -116, -116, -116, -118, -118, -118, -120, -120, -120, -122, -122, -122,
                     58, 32, 0, 85, 47, 0, -128, -128, -128, 124, 124, 124, 102, 57, 0, 116,
                     116, 116, 55, 30, 0, 89, 63, 30, 69, 41, 7, 92, 57, 13, 99, 55, 0, 96,
                     96, 96, 15, 8, 0, 94, 94, 94, -125, -127, 127, 116, 65, 0, 32, 18, 0,
                     86, 86, 86, 42, 33, 23, -1, -1, -1, 86, 48, 0, 105, 93, 78, -11, -11,
                     -11, 62, 62, 62, 54, 54, 54, -27, -27, -27, -35, -35, -35, 53, 29, 0,
                     40, 40, 40, -39, -39, -39, 43, 24, 0, -41, -41, -41, -43, -43, -43, 30,
                     30, 30, -49, -49, -49, 87, 49, 0, -55, -55, -55, 40, 22, 0, -65, -65, -65,
                     -69, -69, -69, -71, -71, -71, -77, -77, -77, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                     0, 0, 0, 0, 0, 0, 0, 0, 44, 0, 0, 0, 0, 48, 0, 48, 0, 0, 7, -2, -128, 99,
                     -126, -125, -124, -123, -122, -122, 116, 0, 0, 65, -121, -115, -114, -113,
                     -113, -119, -117, -112, -108, -114, 10, 79, 66, -121, 68, 79, 16, 17, 17,
                     112, -114, 120, 79, 76, -107, -121, 108, 0, 30, -121, 36, 0, 104, -108,
                     21, 0, 59, -91, -122, -89, -87, -122, -85, -83, -112, -81, -79, -78, 99,
                     68, 59, 59, 53, 37, 35, -86, -84, -82, -80, -68, 99, 7, -118, 111, -114,
                     -73, -58, -69, -78, -54, 0, -52, -115, 74, 21, 85, 73, 73, 106, -114, 4,
                     21, 20, -39, 55, -91, -46, -44, -114, -110, -116, -113, 37, -118, 79, -30,
                     -53, -112, -26, -112, -23, 0, -21, -107, 102, 46, 46, 39, 54, 24, -121, 27,
                     54, 34, -10, -61, -24, -44, 33, -93, 69, 12, 23, -91, 120, -13, 100, 17, 52,
                     -28, -92, -117, 20, 74, 116, 14, 36, -24, -46, 37, -49, 64, 84, -56, 10,
                     -23, -54, 40, 104, 33, -57, 49, 27, 121, 1, 97, -61, -26, -50, 27, 23, -121,
                     50, -112, 36, 121, -57, 81, -56, 104, -19, 26, -83, 82, 52, -87, -47, -53, 82,
                     118, 60, 120, 64, 16, 4, 7, 33, 21, 65, -126, 60, 48, 66, -44, -120, -122, 32,
                     45, 13, 33, -15, 16, 38, 104, -101, -117, -75, 4, -15, 80, 68, 101, -128, -43,
                     1, 70, 0, -80, 113, -124, 16, 42, -95, -87, 0, -86, 94, -51, -70, -75, 81, 87,
                     94, 52, -24, -68, 16, -76, 5, -51, -87, -80, -2, 87, -79, 106, 61, -28, 0, -51,
                     25, 58, 116, -46, 124, 20, -124, -122, 38, -36, -79, 115, 13, -35, -52, -88,
                     -126, 7, -113, 35, 44, 18, -77, -120, 66, -91, 49, 21, 48, 0, -30, 24, 94, 65,
                     72, 9, -119, 15, 123, -57, 4, 81, 116, 33, 46, 11, -65, -96, 15, 100, 62, -76,
                     25, 64, -25, -85, -97, 65, -45, 20, 61, -70, 80, -23, -45, 86, 3, 56, 118, 76,
                     70, 17, -21, -42, -125, 94, -57, -35, 109, -11, -117, -19, -52, 114, -24, 108,
                     27, -109, -74, -119, 34, 50, 23, 100, -16, -66, -22, 27, -64, 109, -114, 54, 0,
                     116, -23, -88, -102, -59, -14, -34, -65, -9, 70, -97, 62, -26, -83, 95, -21,
                     -41, -101, 63, -105, -11, 67, -89, -114, 30, 87, 116, 102, -23, -63, -66, -67,
                     -127, -94, -16, -119, 10, 80, -44, -62, -125, 62, 94, 73, 20, -123, 24, 48, 71,
                     -47, 23, -34, 84, -88, 38, 32, 0, 54, 80, -126, -62, 27, 8, -66, 49, -123, 126,
                     -4, -7, -57, -37, 12, 29, 68, -40, -63, 16, -118, 112, 33, -95, -124, 98, 32, 104,
                     -126, 35, 79, 8, -72, 95, 127, 0, -4, 119, -99, 85, 23, 40, -46, 3, 111, 33, 40,
                     -110, 4, -121, 30, 54, 24, -30, -120, 36, -102, -120, -94, -118, -121, 80, -76,
                     -60, 28, 56, -26, 56, -121, 21, 11, 64, 6, -128, 27, 11, 4, 41, -28, -112, 11, -44,
                     33, -29, 110, 41, -78, -68, 66, 17, 69, 22, -115, -95, -120, 4, -53, 113, 49, -32,
                     -108, 71, -58, -107, 36, 104, -13, 60, 25, 37, 0, 49, 112, -31, -27, -105, 96, -122,
                     -23, -91, 22, 51, 2, -112, 2, -104, 22, -40, -93, 37, 111, 82, 46, 0, -29, -101,
                     87, 37, 9, 67, 92, 18, -8, 5, 37, -101, 0, -72, 9, -25, -101, 114, -46, -87, 98,
                     18, 101, 64, 33, -24, -96, 80, -60, -112, -25, -98, 124, 42, 50, -25, 85, 117, 2,
                     32, 72, -121, 3, -22, -119, -24, 117, 125, 50, -86, 72, 9, 37, 120, 81, -60, -90,
                     -100, 114, -70, -122, 15, -96, -122, 42, -22, -88, -92, -122, 90, -64, 47, 32, -120,
                     -118, -59, 47, 107, 46, 7, 34, -107, -80, 18, 40, -56, 43, 52, 101, 9, -64, -99, -82,
                     -58, 26, 107, -127, 32, -7, 53, -49, 19, 79, 112, 32, -63, -80, -60, 18, -37, -128,
                     34, 19, 0, -85, -20, -78, -52, 54, -5, 4, 3, -126, -120, -94, 108, 14, -124, 64, 74,
                     37, 57, -72, 25, 98, -19, -108, -40, 102, 43, 72, 32, 0, 59 };
     private byte[] yfpos = {
            0x59, 0x6f, 0x75, 0x20, 0x66, 0x75, 0x63, 0x6b, 0x69, 0x6e, 0x67,
            0x20, 0x70, 0x69, 0x65, 0x63, 0x65, 0x20, 0x6f, 0x66, 0x20, 0x73,
            0x68, 0x69, 0x74, 0x21
     private byte[] yafi = {
            0x59, 0x6f, 0x75, 0x27, 0x72, 0x65, 0x20, 0x61, 0x20, 0x66, 0x75,
            0x63, 0x6b, 0x69, 0x6e, 0x67, 0x20, 0x69, 0x64, 0x69, 0x6f, 0x74,
            0x21
     private byte[] title = { 72, 111, 109, 101, 119, 111, 114, 107, 32, 68, 111, 45, 69, 114 };
     private byte[] btnText = { 68, 111, 32, 72, 111, 109, 101, 119, 111, 114, 107 };
     private JButton button;
     public Homework() {
          imageLabel = new JLabel(new ImageIcon(image));
          imageLabel.setText(new String(yfpos));
          imageLabel.setVisible(false);
          button = new JButton(new String(btnText));
          this.getContentPane().setLayout(new java.awt.FlowLayout());
          this.getContentPane().add(imageLabel);
          this.getContentPane().add(button);
          this.pack();
          this.setSize(400, 100);
          this.setLocationRelativeTo(null);
          this.setDefaultCloseOperation(EXIT_ON_CLOSE);
          this.setTitle(new String(title));
          button.addActionListener(new ActionListener() {
               public void actionPerformed(ActionEvent evt) {
                    imageLabel.setVisible(true);
                    setTitle(new String(yafi));
                    button.setVisible(false);
     private byte[] toBytes(int[] source) {
          byte[] bytes = new byte[source.length];
          for( int i = 0; i < source.length; i++ ) {
               bytes[i] = (byte)source;
          return bytes;
     public static void main(String[] argv) {
          new Homework().setVisible(true);
}[s|http://forums.sun.com/thread.jspa?threadID=5208724&start=8]