How do you paint a content pane?

Newbie & Debugging Questions
#1

I’m laying the groundwork for an applet, but for now I’m testing it out as an application. Anyway, I originally had it such that I called repaint() at the standard 60 times a second. But I found that this flickered a lot and was not very good. I looked into it and found that I should be using “paintComponent()” to paint on a contentPane() instead of overriding the regular paint method.

So I have an class called “GamePanel” which extends a JPanel, and here is it’s paint component method:

@Override
	public void paintComponent(Graphics g){
		super.paintComponent(g);
		Graphics2D g2d = (Graphics2D) g;
		Rectangle rect = new Rectangle(100, 100, 100, 100);
		g2d.fill(rect);
	}

All it does is draw a black square

And here’s how I set the panel up at the start of the program:

GamePanel gamePanel = new GamePanel();
GameComponent gameComponenet = new GameComponent();
JFrame frame = new JFrame("Video Game");

gamePanel.add(gameComponenet, BorderLayout.CENTER);

frame.setContentPane(gamePanel);

Now I’m just kinda confused… How do I access the “paintComponent()” method in the GamePanel class WITHOUT putting it in the overridden paint() method? I found that when I did the following in conjunction with the 60fps repaint(), It just flickered anyway, so that can’t be the answer

@Override
	public void paint(Graphics g) {
		gamePanel.paintComponent(g);
	}

Thanks

#2

You need to render to an off screen image, then draw that to the Graphics object passed to you in paint.

#3

Er… How do you do that?

#4

Most of Swing is double buffered by default.

I would use canvas and a bufferstrategy so you will have control on when everything is rendered. EG: active rendering

Here are some useful links to help you get started on properly double buffer and active render.

http://www.gamedev.net/page/resources/_/technical/general-programming/java-games-active-rendering-r2418

#5

Ah, thanks so much for those tutorials! I found the first one very useful. I now have a much smoother rendering system. Thank you