flickering problem

[dimril]

I write a game (Lunar lander) and I've got a problem with flickering, but when I put it in double buffer, everything becomes screwed - it just doesn't show or flickers so badly that nothing is visible.

I paint in a panel, it looks like this:

    	Graphics g = bf.getDrawGraphics();
        super.paint(g);
        
        RenderingHints rh =
            new RenderingHints(RenderingHints.KEY_ANTIALIASING,
                               RenderingHints.VALUE_ANTIALIAS_ON);

        rh.put(RenderingHints.KEY_RENDERING,
             RenderingHints.VALUE_RENDER_QUALITY);

        ((Graphics2D) g).setRenderingHints(rh);
		
        
        Graphics2D g2d = (Graphics2D)g;

        currentLevel.draw(g2d);

        if (craft.isVisible())
            g2d.drawImage(craft.getImage(), craft.getX(), craft.getY(),
                              this);
        else if (craft.isCrashing())
        	g2d.drawImage(craft.getImage(), craft.getX(), craft.getY(),
                    this);
        
        if (ingame) {
            craft.drawClocks(g2d);
        } else if (timeBuffer < 0){
        	String msg = "Game over";
        	setBackground(Color.BLACK);
            g.setColor(Color.WHITE);
            
            if(craft.isVisible())
            {
            	msg = "Congratulations!";
            	setBackground(Color.WHITE);
                g.setColor(Color.BLACK);
                
            }
        	Font small = new Font("Helvetica", Font.BOLD, 14);
            FontMetrics metr = this.getFontMetrics(small);

            
            g.setFont(small);
            g.drawString(msg, (getWidth() - metr.stringWidth(msg)) / 2,
                         getHeight() / 2);
        }

        g.dispose();
        
        bf.show();
        Toolkit.getDefaultToolkit().sync();

full code in attachment, binaries in rapidshare:
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[mrmatt1111]

All drawing should be done within the overwritten paintComponent(...) method of your JPanel.

[dimril]

using paintComponent() unfortunately did nothing to help :/

[edit] I put setDoubleBuffered(true) in a constructor, but I don't know if it ensures doublebuffering. I need it only to be, because it's my semester project on Java.

[Maxideon]

Take that code snippet you posted and place it in the paintComponent method.

public void paintComponent(Graphics g) {
   ...
}

Delete the first line

Graphics g = bf.getDrawGraphics();

Change the next line to

super.paintComponent(g);

And delete the last three lines,

g.dispose();
bf.show();
Toolkit.getDefaultToolkit().sync();

Basically, get rid or your BufferStrategy. You're not doing active rendering so it's not needed. And it's intertwining with Swing's own repaint mechanism to cause the flicker.

[camickr]

I'll just add that Swing is double buffered by default.

[dimril]

Thanks, guys :) You've helped a lot :)