Killer Game Programming in Java

The Animation Framework

JackPanel is a subclass of JPanel and implements the animation framework described in Chapters 2 and 3; JackPanel resembles the BugPanel class of Chapter 11.

The JackPanel() constructor in Example 12-1 creates the game entities: the RibbonsManager, BricksManager, JumperSprite, and FireBallSprite objects. It prepares the explosion animation and the title/help screen.

Example 12-1. The JackPanel constructor

    // some of the globals
    private JumpingJack jackTop;
    private JumperSprite jack;          // the sprites
    private FireBallSprite fireball;
    private RibbonsManager ribsMan;     // the ribbons manager
    private BricksManager bricksMan;    // the bricks manager

    // to display the title/help screen
    private boolean showHelp;
    private BufferedImage helpIm;

    // explosion-related
    private ImagesPlayer explosionPlayer = null;
    private boolean showExplosion = false;
    private int explWidth, explHeight;   // image dimensions
    private int xExpl, yExpl;   // coords where image is drawn


    public JackPanel(JumpingJack jj, long period)
    {
      jackTop = jj;
      this.period = period;

      setDoubleBuffered(false);
      setBackground(Color.white);
      setPreferredSize( new Dimension(PWIDTH, PHEIGHT));

      setFocusable(true);
      requestFocus();    // so receives key events

      addKeyListener( new KeyAdapter() {
        public void keyPressed(KeyEvent e)
        { processKey(e); }
      });

      // initialise the loaders
      ImagesLoader imsLoader = new ImagesLoader(IMS_INFO);
      clipsLoader = new ClipsLoader(SNDS_FILE);

      // initialise the game entities bricksMan = new BricksManager(PWIDTH, ...