Sprites in Java

/*
 * Created on 06.02.2005@14:00:31
 *
 * TODO Licence info
 */
package de.tutorials;

import java.awt.Graphics2D;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.awt.image.VolatileImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.JFrame;

/**
 * @author Administrator
 *
 * TODO Explain me
 */
public class TilesTest extends JFrame {

    int screenWidth, screenHeight;

    final int TILE_WIDTH = 32;

    final int TILE_HEIGHT = TILE_WIDTH;

    int tilePosX;

    int tilePosY;

    final int TILE_COLUMN_CNT = 7;

    final int TILE_ROW_CNT = 6;

    VolatileImage[] tiles;

    BufferStrategy strategy;

    private Thread renderer = new Thread() {
        public void run() {
            int i = 0;
            while (true) {
                Graphics2D g = (Graphics2D) strategy.getDrawGraphics();
                g.clipRect(0, 0, screenWidth, screenHeight);
                g.drawImage(tiles[i], tilePosX, tilePosY, TilesTest.this);
                i = ++i % tiles.length;
                g.dispose();
                strategy.show();
                try {
                    Thread.sleep(100L);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    };

    public TilesTest() {
        super("TilesTest");
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        screenWidth = 320;
        screenHeight = 240;

        tilePosX = (screenWidth - TILE_WIDTH) / 2;
        tilePosY = (screenHeight - TILE_HEIGHT) / 2;
        setSize(screenWidth, screenHeight);
        setResizable(false);
        setVisible(true);
        initGFX();
        createBufferStrategy(2);
        strategy = getBufferStrategy();
    }

    /**
     * 
     */
    private void initGFX() {
        try {
            BufferedImage tilesMap = ImageIO
                    .read(new File("c:/dg_humans32.gif"));
            int width = tilesMap.getWidth();
            int height = tilesMap.getHeight();

            tiles = new VolatileImage[TILE_ROW_CNT * TILE_COLUMN_CNT];

            for (int i = 0, y = 0; i < TILE_ROW_CNT; i++) {
                for (int j = 0, x = 0; j < TILE_COLUMN_CNT; j++) {
                    VolatileImage vImg = this.createVolatileImage(TILE_WIDTH,
                            TILE_HEIGHT);
                    vImg.getGraphics()
                            .drawImage(
                                    tilesMap.getSubimage(x, y, TILE_WIDTH,
                                            TILE_HEIGHT), 0, 0, this);
                    tiles[i * TILE_ROW_CNT + j] = vImg;
                    x += TILE_WIDTH;
                }
                y += TILE_HEIGHT;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

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

    /**
     * 
     */
    private void start() {
        renderer.start();
    }
}