import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;

public class GameFrame extends Frame {
	private Image offscreen;
	
	public GameFrame() {
		addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});
	}
	
	public void paint(Graphics g) {
		if(offscreen == null) {
			offscreen = createImage(getSize().width, getSize().height);
		}
		Graphics og = offscreen.getGraphics();
		og.setClip(0, 0, getSize().width, getSize().height);
		og.clearRect(0, 0, getSize().width, getSize().height);
		super.paint(og);
		og.dispose();
		g.drawImage(offscreen, 0, 0, this);
	}
	
	public void invalidate() {
		super.invalidate();
		offscreen = null;
	}
	
	public void update(Graphics g) {
		paint(g);
	}
}