import java.awt.AWTEvent;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.event.KeyEvent;
import java.awt.image.BufferStrategy;

import javax.swing.JFrame;

public class Example extends JFrame {
	final int FRAME_TIME = 1000 / 60; // ~60fps
	int font_height = 10;
	int width_in_chars = 80;

	int height_in_chars = 40;
	BufferStrategy strategy;
	boolean keys[] = new boolean[65536];
	boolean mouse[] = new boolean[8];
	int mouseX = 0;

	int mouseY = 0;

	public Example() {
		Font font = new Font(Font.MONOSPACED, Font.PLAIN, font_height);
		int win_width = width_in_chars * getFontMetrics(font).charWidth(' ');
		int win_height = height_in_chars * font_height;

		setTitle("Example Project");
		setResizable(false);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setUndecorated(true);
		setFont(font);
		setSize(win_width, win_height);
		setLocationRelativeTo(null);
		setIgnoreRepaint(true);
		setVisible(true);

		enableEvents(AWTEvent.KEY_EVENT_MASK | AWTEvent.MOUSE_EVENT_MASK
				| AWTEvent.MOUSE_MOTION_EVENT_MASK);
		createBufferStrategy(2);

		strategy = getBufferStrategy();
	}

	void mainLoop() {
		long lastFrame = System.nanoTime();

		while (!keys[KeyEvent.VK_ESCAPE]) {
			drawToBuffer();
			strategy.show();

			do
				try {
					Thread.sleep(FRAME_TIME / 2);
				} catch (InterruptedException e) { }
			while (System.nanoTime() < lastFrame + FRAME_TIME * 1000000);
			lastFrame = System.nanoTime();
		}
		System.exit(0);
	}

	private void drawToBuffer() {
		Graphics2D buffer = (Graphics2D) strategy.getDrawGraphics();
		buffer.drawLine(0, 0, 100, 100);
		buffer.dispose();
	}
	
	@Override
	public void processKeyEvent(KeyEvent e) {
		keys[e.getKeyCode()] = e.getID() == KeyEvent.KEY_PRESSED;
	}
	
	public static void main(String[] args) {
		new Example().mainLoop();
	}
}