[JAVA] (펌)자바 게임 제작 예제

[JAVA] (펌)자바 게임 제작 예제
짧지만 정말 강력한 코드.
책에는 퓨어 자바로 게임을 만들어도 빠르다던데, 왜 내가 짠 게임은 느릴까 늘 좌절해왔다.
알고 보니 딱 한 가지 포인트였다. 허탈하지만 이제라도 알게 되어서 다행이다.
* 예제코드는 아래 유튜브의 내용을 그대로 퍼온 것임.

package ca.vanzenben.game;

import java.awt.BorderLayout;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;

import javax.swing.JFrame;

public class Game extends Canvas implements Runnable {

    private static final long serialVersionUID = 1L;

    public static final int WIDTH = 160;
    public static final int HEIGHT = WIDTH / 12 * 9;
    public static final int SCALE = 3;
    public static final String NAME = “Game”;

    private JFrame frame;

    public boolean running = false;
    public int tickCount = 0;

    private BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
    private int[] pixels = ((DataBufferInt) image.getRaster().getDataBuffer()).getData();

    public Game() {
        setMinimumSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));
        setMaximumSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));
        setPreferredSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));

        frame = new JFrame(NAME);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new BorderLayout());

        frame.add(this, BorderLayout.CENTER);
        frame.pack();

        frame.setResizable(false);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public synchronized void start() {
        running = true;
        new Thread(this).start();
    }

    public synchronized void stop() {
        running = false;
    }

    public void run() {
        long lastTime = System.nanoTime();
        double nsPerTick = 1000000000D / 60D;

        int frames = 0;
        int ticks = 0;

        long lastTimer = System.currentTimeMillis();
        double delta = 0;

        while (running) {
            long now = System.nanoTime();
            delta += (now – lastTime) / nsPerTick;
            lastTime = now;
            boolean shouldRender = true;
            while (delta >= 1) {
                ticks++;
                tick();
                delta -= 1;
                shouldRender = true;
            }

            try {
                Thread.sleep(2);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            if (shouldRender) {
                frames++;
                render();
            }

            if (System.currentTimeMillis() – lastTimer >= 1000) {
                lastTimer += 1000;
                System.out.println(ticks + ” ticks, ” + frames + ” frames”);
                frames = 0;
                ticks = 0;
            }
        }
    }

    public void tick() {
        tickCount++;

        for (int i = 0; i < pixels.length; i++) {
            pixels[i] = i + tickCount;
        }
    }

    public void render() {
        BufferStrategy bs = getBufferStrategy();
        if (bs == null) {
            createBufferStrategy(3);
            return;
        }

        Graphics g = bs.getDrawGraphics();

        g.setColor(Color.BLACK);
        g.fillRect(0, 0, getWidth(), getHeight());

        g.drawImage(image, 0, 0, getWidth(), getHeight(), null);

        g.dispose();
        bs.show();
    }

    public static void main(String[] args) {
        new Game().start();
    }
}