OMG it is still flickering.

Conflux

Senior Newbie

Java games rock!

OMG it is still flickering.

« Posted 2003-11-18 10:03:26 »

Hi folks!

I was trying to create a small space-shooter (pong style) to get some experience with java 2D and realtime rendering.

a jar containing a runnable version can be found at: http://www.hdm-stuttgart.de/~ml18/jumat/jumat.zip

My problem is, that the movement of the ships is still flickering although I am using double-buffering.

Further implementations should be socket or RMI based multiplayer so I decided to run the game in a seperate thread (perhaps this could be useful later, but don't know exactly)

But even if I remove the Thread and run the game in the main Thread (it gets up to 30000fps) the flickering still exists Sad

Here's the main part of the code:

The Frame containg a JPanel in the center:

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public class GameWindow extends JFrame implements Runnable {

  private ScenePanel pScene = new ScenePanel(this);
  BorderLayout borderLayout1 = new BorderLayout();
  boolean running = true;
  boolean left = false;
  boolean right = false;
  boolean fire = false;
  boolean lock = false;

  int screenwidth = 800;
  int screenheight = 600;
  int fps;
  int dir = 1; // TEST: Player2 automove direction
  float frameduration;
  Ship player1 = new Ship("gfx/bat.gif", 368, 480, 300, 800, 100);
  Ship player2 = new Ship("gfx/cow.gif", 368, 40, 250, 850, 100);

  public GameWindow() {
    this.setResizable(false);
    this.setTitle("Spacefight");
    this.addKeyListener(new java.awt.event.KeyAdapter() {
      public void keyPressed(KeyEvent e) {
        this_keyPressed(e);
      }
    });
    this.addKeyListener(new java.awt.event.KeyAdapter() {
      public void keyReleased(KeyEvent e) {
        this_keyReleased(e);
      }
    });
    this.getContentPane().setLayout(borderLayout1);
    this.getContentPane().add(pScene,  BorderLayout.CENTER);
    setSize(screenwidth, screenheight);
      
      Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
      Dimension size = getSize();
      screenSize.height = screenSize.height/2;
      screenSize.width = screenSize.width/2;
      size.height = size.height/2;
      size.width = size.width/2;
      int y = screenSize.height - size.height;
      int x = screenSize.width - size.width;
      setLocation(x, y);

      
    setVisible(true);
    addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });
  }
  void this_keyPressed(KeyEvent e) {
    if (e.getKeyCode() == KeyEvent.VK_SPACE) {
      if(!lock) {
        lock = true;
        fire = true;
        player1.shot.x = player1.posX+player1.w/2 - player1.shot.w/2;
      }
    }
    if (e.getKeyCode() == KeyEvent.VK_LEFT) {
      right = false;
      left = true;
    }
    if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
      right = true;
      left = false;
    }
  }
  void this_keyReleased(KeyEvent e) {
    if (e.getKeyCode() == KeyEvent.VK_LEFT) {
      left = false;
    }
    if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
      right = false;
    }
  }

  public void run() {
    int count = 0;
    long fpsStartTime = System.currentTimeMillis();
    long  startTime;

    synchronized (this) {
      while (running) {
        startTime = System.currentTimeMillis();
        {try {this.wait(1);}  catch (Exception e) {}}
        pScene.repaint();
        count++;
        if (System.currentTimeMillis() > (fpsStartTime + 999)) {
          fps = count;
          count = 0;
          fpsStartTime = System.currentTimeMillis();
        }
        frameduration = (System.currentTimeMillis() - startTime) / 1000.000f;
        // Begin of Player2 automove
        if (dir==0) {
          if (player2.posX > 8) {
            player2.posX -= player2.movespeed * frameduration;
          }
          else {
            player2.posX = 8;
            dir = 1;
          }
        }
        if (dir==1) {
          if (player2.posX < screenwidth-player2.w-12) {
            player2.posX += player2.movespeed * frameduration;
          }
          else {
            player2.posX = screenwidth-player2.w-12;
            dir = 0;
          }
        }
        // End of Player2 automove
        if (left) {
          if (player1.posX > 8) {
            player1.posX -= player1.movespeed * frameduration;
          }
          else {
            player1.posX = 8;
          }
        }
        if (right) {
          if (player1.posX < screenwidth-player1.w-12) {
            player1.posX += player1.movespeed * frameduration;
          }
          else {
            player1.posX = screenwidth-player1.w-12;
          }
        }
        if (fire) {
          player1.shot.y -= player1.firespeed * frameduration;
          if (player2.checkHit(player1.shot)) {
            player2.hitpoints -= player1.shot.dmg;
            player1.shot.y = player1.shot.initY;
            fire = false;
            lock = false;
            if (player2.hitpoints <= 0) {
              player2.hitpoints = 100; // TEST: explosion will follow. GAME OVER
            }
          }
          if (player1.shot.y <= 0) {
            player1.shot.y = player1.shot.initY;
            fire = false;
            lock = false;
          }
        }
      }
    }
  }

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

}

The JPanel where the drawing takes place

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class ScenePanel extends JPanel {

   GameWindow gw;
   Image back = loadImage("gfx/stars0001.jpg");
   private int bufferWidth;
   private int bufferHeight;
   private Image bufferImage;
   private Graphics bufferGraphics;

   private MediaTracker mt;

   ScenePanel(GameWindow gw) {
     this.gw = gw;
   }

   public Image loadImage(String file) {
     Image img = Toolkit.getDefaultToolkit().getImage(file);
     mt = new MediaTracker(this);
     mt.addImage(img, 0);
     try {
       mt.waitForAll();
     }
     catch (InterruptedException e) { e.printStackTrace(); }
     return img;
   }

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

   public void paint(Graphics g){
     if(bufferWidth!=getSize().width || bufferHeight!=getSize().height || bufferImage==null || bufferGraphics==null)
       resetBuffer();
     if(bufferGraphics!=null){
       bufferGraphics.clearRect(0,0,bufferWidth,bufferHeight);
       paintBuffer(bufferGraphics);
       g.drawImage(bufferImage,0,0,this);
     }
   }

   private void resetBuffer(){
     bufferWidth=getSize().width;
     bufferHeight=getSize().height;
     if(bufferGraphics!=null){
       bufferGraphics.dispose();
       bufferGraphics=null;
     }
     if(bufferImage!=null){
       bufferImage.flush();
       bufferImage=null;
     }
     System.gc();
     bufferImage=createImage(bufferWidth,bufferHeight);
     bufferGraphics=bufferImage.getGraphics();
   }


   public void paintBuffer(Graphics g) {
     g.drawImage(back, 0, 0, this);
     g.drawImage(gw.player1.img, gw.player1.posX, gw.player1.posY, this);
     g.drawImage(gw.player2.img, gw.player2.posX, gw.player2.posY, this);
     g.setColor(Color.green);
     g.drawRect(gw.player2.posX, gw.player2.posY, gw.player2.w, gw.player2.h);
     g.drawRect(gw.player1.posX, gw.player1.posY, gw.player1.w, gw.player1.h);
     if (gw.fire) {
       g.drawImage(gw.player1.shot.img, gw.player1.shot.x, gw.player1.shot.y, this);
     }
     g.setColor(Color.red);
     g.fillRect(636,10,(int)(gw.player2.hitpoints*1.5),10);
     g.fillRect(636,553,(int)(gw.player1.hitpoints*1.5),10);
     g.setColor(Color.orange);
     g.drawString("FPS: " + gw.fps, 4, 16);

   }
 }

Would be really cool if someone could help me figure out where the flicker comes from

kevglass

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