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POWhat is wrong with this applet gameloop?
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copied!<p>It seems like this applet will only draw and update DRAWS when the window is resized or minimized. So the applet will not repaint all the time, but only when manipulating the window. </p> <p>Am I doing something wrong here?</p> <p>I am following the gameloop presented here: <a href="http://www3.ntu.edu.sg/home/ehchua/programming/java/J8d_Game_Framework.html" rel="nofollow">http://www3.ntu.edu.sg/home/ehchua/programming/java/J8d_Game_Framework.html</a></p> <p>The code is here:</p> <pre><code>package newapplet; import java.awt.*; import java.awt.event.*; import javax.swing.*; public class GameApplet extends JApplet { // main class for the game as a Swing application // Define constants for the game static final int CANVAS_WIDTH = 493; // width and height of the game screen static final int CANVAS_HEIGHT = 411; static final int UPDATE_RATE = 4; // number of game update per second static final long UPDATE_PERIOD = 1000000000L / UPDATE_RATE; // nanoseconds static int DRAWS = 0; // ...... // Enumeration for the states of the game. public enum gameState { INITIALIZED, CONNECTING, PLAYING, DISCONNECTED } private gameState state; // Define instance variables for the game objects // ...... // ...... // Handle for the custom drawing panel private GameCanvas canvas; // Constructor to initialize the UI components and game objects public GameApplet() { // Initialize the game objects gameInit(); // UI components canvas = new GameCanvas(); canvas.setPreferredSize(new Dimension(CANVAS_WIDTH, CANVAS_HEIGHT)); this.setContentPane(canvas); // Other UI components such as button, score board, if any. // ...... this.setVisible(true); } // All the game related codes here // Initialize all the game objects, run only once in the constructor of the main class. public void gameInit() { // ...... state = gameState.INITIALIZED; } // Shutdown the game, clean up code that runs only once. public void gameShutdown() { // ...... state = gameState.DISCONNECTED; } // To start and re-start the game. public void gameStart() { // Create a new thread Thread gameThread = new Thread() { // Override run() to provide the running behavior of this thread. @Override public void run() { gameLoop(); } }; // Start the thread. start() calls run(), which in turn calls gameLoop(). gameThread.start(); } // Run the game loop here. private void gameLoop() { // Regenerate the game objects for a new game // ...... //state = State.PLAYING; // Game loop long beginTime, timeTaken, timeLeft; while (true) { beginTime = System.nanoTime(); if (state == gameState.DISCONNECTED) break; // break the loop to finish the current play if (state == gameState.PLAYING) { // Update the state and position of all the game objects, // detect collisions and provide responses. gameUpdate(); } // Refresh the display repaint(); // Delay timer to provide the necessary delay to meet the target rate timeTaken = System.nanoTime() - beginTime; timeLeft = (UPDATE_PERIOD - timeTaken) / 1000000L; // in milliseconds if (timeLeft < 10) timeLeft = 10; // set a minimum try { // Provides the necessary delay and also yields control so that other thread can do work. Thread.sleep(timeLeft); } catch (InterruptedException ex) { } } } // Update the state and position of all the game objects, // detect collisions and provide responses. public void gameUpdate() { } // Refresh the display. Called back via rapaint(), which invoke the paintComponent(). private void gameDraw(Graphics2D g2d) { switch (state) { case INITIALIZED: g2d.setColor (Color.red); g2d.drawString ("init",20,20); break; case PLAYING: g2d.setColor (Color.red); g2d.drawString ("play",20,20); break; case CONNECTING: g2d.setColor (Color.red); g2d.drawString ("connecting",20,20); break; case DISCONNECTED: g2d.setColor (Color.red); g2d.drawString ("disconnect",20,20); break; } g2d.setColor (Color.GREEN); g2d.drawString ("Re-paint: " + DRAWS,30,30); this.DRAWS++; // ...... } // Process a key-pressed event. Update the current state. public void gameKeyPressed(int keyCode) { switch (keyCode) { case KeyEvent.VK_UP: // ...... break; case KeyEvent.VK_DOWN: // ...... break; case KeyEvent.VK_LEFT: // ...... break; case KeyEvent.VK_RIGHT: // ...... break; } } // Process a key-released event. public void gameKeyReleased(int keyCode) { } // Process a key-typed event. public void gameKeyTyped(char keyChar) { } // Other methods // ...... // Custom drawing panel, written as an inner class. class GameCanvas extends JPanel implements KeyListener { // Constructor public GameCanvas() { setFocusable(true); // so that can receive key-events requestFocus(); addKeyListener(this); } // Override paintComponent to do custom drawing. // Called back by repaint(). @Override public void paintComponent(Graphics g) { Graphics2D g2d = (Graphics2D)g; super.paintComponent(g2d); // paint background setBackground(Color.BLACK); // may use an image for background // Draw the game objects gameDraw(g2d); } // KeyEvent handlers @Override public void keyPressed(KeyEvent e) { gameKeyPressed(e.getKeyCode()); } @Override public void keyReleased(KeyEvent e) { gameKeyReleased(e.getKeyCode()); } @Override public void keyTyped(KeyEvent e) { gameKeyTyped(e.getKeyChar()); } } // main public static void main(String[] args) { // Use the event dispatch thread to build the UI for thread-safety. SwingUtilities.invokeLater(new Runnable() { @Override public void run() { new GameApplet(); } }); } } </code></pre>

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