JDK 1.4.2 and full-screen mode

Question

Hi all,
I'm messing around with a 2D-elite clone using Java 1.4 full-screen mode. After a few hours of work I am happily zapping asteroids and aliens at a zippy 140 FPS.
I then switch from JDK 1.4.0_01 to 1.4.2_01 in the hope of getting some extra speed. Without making any other changes to the code, things suddenly start crawling along at <30 FPS.
I am using BufferStrategy in combination with a VolatileImage to draw everything on. Did I miss any important changes in the newest release of the JDK or am I doing something fundamentally wrong?
Raf

Answer 1

Hi Abuse,
Thanks for answering. First of all, my speed calculations are a bit crufty. In my main thread, I do a System.currentTimeMillis() every 1000th call. I consider 10^6 / (this time in ms - last time in ms) to be the speed in FPS. It's probably wildly off, but the difference in speed between the two JDKs is noticeable even without the numbers.
Posting all of the code is going to be a bit difficult because there's quite a few classes in the project. However, I'll try to isolate the relevant code below.
At this point, I'm not entirely convinced that the drawing is the problem. I'm using a shoddy integrated video card which may be causing the issues, but even if I only draw the background starfield I see a significant drop in speed. I'll try to disable some code here and there in the hope of finding something more specific.
I'm playing some music in the background and there is rather a lot of collision-handling code going on, maybe that's the bottle-neck. When you bump into stuff, the trajectory of your ship and whatever you rammed is altered depending on weight, velocity and angle. It's a lot of fun to watch but still quite buggy at this point. (I've got a planet on-screen which acts rather like a beach-ball when I ram it).
Anyhow, here's the rendering code:
This class takes care of the initialization of the full-screen mode.
Actual drawing is done in the Level class below.
public class Main implements Runnable {
    private long lastTime = System.currentTimeMillis();
    double frameCount = 0;
    public static final int BUFFER_COUNT = 1;
    private JFrame frame;
    BufferStrategy bufferStrategy;
    GraphicsDevice device;
    private BigScreen screen;
    private static final int DRAW_DELAY = 5;
    public static void main(String[] args) {
        Main main = new Main();
    public Main() {
        this.initializeSettings();
        this.initializeGUI();
        new Thread(this).start();
        new Thread(new HouseKeeping()).start();
    private void initializeSettings() {
        Tools.loadEntityTypes();
        SoundManager.getHandle().playMusic();
    private void initializeGUI() {
        GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();
        device = env.getDefaultScreenDevice();
        GraphicsConfiguration gc = device.getDefaultConfiguration();
        frame = new JFrame(gc);
        frame.setTitle("Elite 2D");
        frame.setUndecorated(true);
        frame.setResizable(false);
        frame.setIgnoreRepaint(true);
        frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        device.setFullScreenWindow(frame);
        Level.getHandle().setDimensions((int) device.getDefaultConfiguration().getBounds().getWidth(),
                (int) device.getDefaultConfiguration().getBounds().getHeight());
        BufferCapabilities bc = new BufferCapabilities(new ImageCapabilities(true),
                new ImageCapabilities(true),
                BufferCapabilities.FlipContents.BACKGROUND
        try {
            frame.createBufferStrategy(BUFFER_COUNT, bc);
        } catch (AWTException e) {
            e.printStackTrace();
        bufferStrategy = frame.getBufferStrategy();
        int width = device.getDisplayMode().getWidth();
        int height = device.getDisplayMode().getHeight();
        screen = new BigScreen(width, height, gc.createCompatibleVolatileImage(width, height));
        frame.getContentPane().add(screen);
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            public void windowDeiconified(WindowEvent e) {
                GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();
                device = env.getDefaultScreenDevice();
                GraphicsConfiguration gc = device.getDefaultConfiguration();
                device.setFullScreenWindow(null);
                device.setFullScreenWindow(frame);
                BufferCapabilities bc = new BufferCapabilities(new ImageCapabilities(true),
                        new ImageCapabilities(true),
                        BufferCapabilities.FlipContents.COPIED
                try {
                    frame.createBufferStrategy(BUFFER_COUNT, bc);
                } catch (AWTException awt) {
                    awt.printStackTrace();
        // Set the cursor to a transparent image
        Image image = Toolkit.getDefaultToolkit().createImage(
                new MemoryImageSource(16, 16, new int[16 * 16], 0, 16));
        Cursor transparentCursor = Toolkit.getDefaultToolkit().createCustomCursor(image,
                new Point(0, 0), "invisiblecursor");
        frame.setCursor(transparentCursor);
        screen.setFocusable(false);
        frame.addKeyListener(getKeyListener());
    public KeyAdapter getKeyListener() {
        return new KeyAdapter() {
            public void keyPressed(KeyEvent e) {
                Level.getHandle().getPlayer().handleKeyUp(e.getKeyCode());
            public void keyReleased(KeyEvent e) {
                Level.getHandle().getPlayer().handleKeyDown(e.getKeyCode());
    public void run() {
        while (true) {
            if (frameCount++ % 1000 == 0) {
                long thisTime = System.currentTimeMillis();
                // aantal ms voor 1000 frames
                // 1000 * (aantal frames / seconde)
                double fps = thisTime - lastTime;
                lastTime = thisTime;
                Level.getHandle().getConsole().addConsoleMessage("FPS : " + 1000000 / fps);
            Graphics g = bufferStrategy.getDrawGraphics();
            screen.paintSurroundings();
            g.drawImage(screen.background, 0, 0, null);
            g.dispose();
            bufferStrategy.show();
            try {
                Thread.sleep(DRAW_DELAY);
            } catch (InterruptedException e) {
            } catch (IllegalStateException i) {
    public Rectangle getScreenDimensions() {
        return frame.getGraphicsConfiguration().getBounds();
    public void exitFullScreen() {
        device.setFullScreenWindow(null);
} // End class Main// The rendering-code in Level is done in the updateStatus-method.
// Once again, rendering is delegated to the current SolarSystem class.
public class Level {
    private static Level handle;
    public SolarSystem currentSolarSystem;
    private Console console;
    private int width, height;
    private Ship player;
    // All ships within this radius of the player get to act
    private static final int ACTION_RADIUS = 5000;
    // All entities within this radius of the player qualify for drawing
    private static final int VISIBILITY_RADIUS = 2000;
    private Level() {
        console = new Console();
        currentSolarSystem = new SolarSystem();
        Equipment[] weapons = new Equipment[3];
        weapons[0] = new BeamWeapon(Color.red, 1000, 0.02, 0.1);
        weapons[1] = new PulseWeapon(Color.blue, 500, 0, 400, 1);
        weapons[2] = new MissileLauncher();
        player = new Ship(100, 100, weapons, currentSolarSystem);
        currentSolarSystem.addEntity(new Entity(1000, 1000, Tools.getEntityType("planet"), currentSolarSystem));
        for (int i = 0; i < 20; i++) {
            Entity asteroid = Tools.getEntityType("asteroid").createEntity(200 * i, 0, currentSolarSystem);
            asteroid.setSpeed(Tools.getRandom(asteroid.getMaxSpeed()));
            asteroid.setAccelerationAngle(Tools.getRandom(Tools.TWOPI));
            currentSolarSystem.addEntity(asteroid);
        for (int i = 0; i < 5; i++) {
            currentSolarSystem.addEntity(Tools.getEntityType("enemy").createEntity(
                    Tools.getRandom(-1000, 1000), Tools.getRandom(-1000, 1000), currentSolarSystem));
    public SolarSystem getActiveSolarSystem() {
        return this.currentSolarSystem;
    public Console getConsole() {
        return this.console;
    public void setDimensions(int x, int y) {
        this.width = x;
        this.height = y;
    public int getWidth() {
        return this.width;
    public int getHeight() {
        return this.height;
    public static Level getHandle() {
        if (handle == null) {
            handle = new Level();
        return handle;
    public ArrayList getEntitiesInRectangle(int x1, int y1, int w1, int h1) {
        ArrayList intersects = new ArrayList();
        for (int i = 0; i < currentSolarSystem.getEntities().size(); i++) {
            Entity e = (Entity) currentSolarSystem.getEntities().get(i);
            if ((x1 + w1 > e.getX()) && (e.getX() + e.getWidth() > x1) && (y1 + h1 > e.getHeight())
                    && (e.getY() + e.getHeight() > y1)) {
                intersects.add(e);
        return intersects;
    public ArrayList getEntitiesInLine(double x1, double y1, double x2, double y2) {
        ArrayList intersects = new ArrayList();
        Line2D line = new Line2D.Double(x1, y1, x2, y2);
        for (int i = 0; i < currentSolarSystem.getEntities().size(); i++) {
            Entity e = (Entity) currentSolarSystem.getEntities().get(i);
            // System.out.println(e.getBoundingShape() + " vs " + x1 + "x" + y1 + ", " + x2 + "x" + y2);
            if (line.intersects(e.getBoundingShape().getBounds2D())) {
                intersects.add(e);
        return intersects;
    public Entity getNearestEntityToLineOrigin(double x1, double y1, double x2, double y2) {
        double closestIndex = 0;
        Entity closestEntity = null;
        Line2D line = new Line2D.Double(x1, y1, x2, y2);
        for (int i = 0; i < currentSolarSystem.getEntities().size(); i++) {
            Entity e = (Entity) currentSolarSystem.getEntities().get(i);
            // System.out.println(e.getBoundingShape() + " vs " + x1 + "x" + y1 + ", " + x2 + "x" + y2);
            if (line.intersects(e.getBoundingShape().getBounds2D())) {
                double distance = Tools.getDistance(x1, y1, e);
                if (closestEntity == null) {
                    closestEntity = e;
                    closestIndex = distance;
                } else if (distance < closestIndex) {
                    closestEntity = e;
        return closestEntity;
    public Ship getPlayer() {
        return player;
    public void updateStatus(Graphics g, int width, int height) {
        getActiveSolarSystem().updateStatus(g, getPlayer(), width, height);
        getConsole().showConsoleMessages(g);
}Draws a starfield and all visible entities in sight. So far I'm just
drawing all entities in the solar system. Seems to be faster than
figuring out whether objects are near the player for <100 objects.
public class SolarSystem {
    private static final int BIG_STARS = 20;
    private static final int MAX_STARS = 1000;
    private static final int STAR_AREA = 1400;
    private int[][] stars;
    private ArrayList entities;
    private ArrayList explosions;
    public SolarSystem() {
        entities = new ArrayList();
        explosions = new ArrayList();
        this.initializeStarField();
    public ArrayList getEntities() {
        return entities;
    public ArrayList getExplosions() {
        return explosions;
    public void addEntity(Entity e) {
        entities.add(e);
    public void removeEntity(Entity e) {
        entities.remove(e);
    public void addExplosion(int x, int y, int size, int max) {
        // System.out.println("Adding explosion at " + x + " " + y);
        explosions.add(new Explosion(x, y, size, max));
    public void updateStatus(Graphics g, Ship player, int width, int height) {
        this.pollEntities(player);
        this.drawScene(g, player, width, height);
    private void drawScene(Graphics g, Ship player, int width, int height) {
        // Make sure nothing extraneous gets drawn
        g.clipRect(0, 0, width, height);
        // Clear the surface and set the background
        g.setColor(Color.black);
        g.fillRect(0, 0, width, height);
        // Draw explosions & remove from the buffer if needed
        Explosion[] expl = (Explosion[]) getExplosions().toArray(new Explosion[explosions.size()]);
        int centerX = (int) player.getX();
        int centerY = (int) player.getY();
        int widthOffset = centerX + width / 2;
        int heightOffset = centerY + height / 2;
        this.drawStarField(g, player);
        for (int i = expl.length - 1; i >= 0; i--) {
            Explosion ex = expl;
g.setColor(new Color(Math.max(255 - ex.size, 0), 0, 0));
g.drawOval(ex.x - widthOffset, ex.y - heightOffset, ex.size, ex.size);
if (ex.size < ex.max) {
ex.size += 2;
ex.x--;
ex.y--;
explosions.set(i, ex);
} else {
explosions.remove(i);
// todo - can we re-use the active entities table here?
Entity[] entities = getVisibleEntities(player);
for (int i = 0; i < entities.length; i++) {
entities[i].drawEntity((int) (entities[i].getX() - player.getX() + width / 2),
(int) (entities[i].getY() - player.getY() + height / 2), g);
player.drawEntity(width / 2, height / 2, g, entities, width, height);
private void drawStarField(Graphics g, Ship player) {
g.setColor(new Color(255, 255, 255));
int starX = ((int) player.getX() % STAR_AREA);
int starY = ((int) player.getY() % STAR_AREA);
for (int i = 0; i < BIG_STARS; i++) {
g.fillOval((stars[i][0] - starX) % STAR_AREA, (stars[i][1] - starY) % STAR_AREA, 3, 3);
for (int i = BIG_STARS; i < MAX_STARS; i++) {
g.drawLine((stars[i][0] - starX) % STAR_AREA, (stars[i][1] - starY) % STAR_AREA,
(stars[i][0] - starX) % STAR_AREA, (stars[i][1] - starY) % STAR_AREA);
* Includes the player as an active entity
* @param player
* @return
private Entity[] getActiveEntities(Ship player) {
Entity[] activeEntities = (Entity[]) entities.toArray(new Entity[entities.size() + 1]);
activeEntities[activeEntities.length - 1] = player;
return activeEntities;
private void pollEntities(Ship player) {
this.purgeDestroyedObjects();
Entity[] activeEntities = this.getActiveEntities(player);
for (int i = 0; i < activeEntities.length; i++) {
activeEntities[i].resolveAction();
// todo - Handle gravitational pull
//if (activeEntities[i].hasGravitationalPull()) {
// Handle collisions
for (int i = activeEntities.length - 1; i >= 0; i--) {
if (activeEntities[i] != null && !activeEntities[i].isTransparent() && !activeEntities[i].isDestroyed()) {
for (int j = i - 1; j >= 0; j--) {
if (activeEntities[i] != null && activeEntities[j] != null &&
!activeEntities[j].isTransparent() && Tools.entitiesCollide(activeEntities[i], activeEntities[j])) {
handleCollision(activeEntities[i], activeEntities[j]);
// todo - seems redundant - remove by avoiding player ?
if (activeEntities[i].isDestroyed()) {
// System.out.println("Removing " + activeEntities[i]);
activeEntities[i] = null;
if (activeEntities[j].isDestroyed()) {
// System.out.println("Removing " + activeEntities[j]);
activeEntities[j] = null;
private void purgeDestroyedObjects() {
for (int i = entities.size() - 1; i >= 0; i--) {
if (((Entity) entities.get(i)).isDestroyed()) {
entities.remove(i);
private void handleCollision(Entity one, Entity two) {
// Base damage is a factor of total speed & angle.
double collisionFactor = Math.abs(Math.sin((one.getAccelerationAngle() - two.getAccelerationAngle()) / 2));
double explosiveDamage = 0;
if (one.explodesOnImpact()) {
one.onDestroy();
explosiveDamage += one.getExplosiveDamage();
if (two.explodesOnImpact()) {
two.onDestroy();
explosiveDamage += two.getExplosiveDamage();
one.applyDamage(explosiveDamage + (collisionFactor * two.getMass() / one.getMass()));
two.applyDamage(explosiveDamage + (collisionFactor * one.getMass() / two.getMass()));
// Introducing the FACTOR-variable also causes stickiness (two objects glued together after collision)
// FACTOR determines how much of the energy is transfered from entity 1 to 2, and how much remains
double FACTOR = 0.9;
// Don't delete v1 and a1!
double v1 = one.getSpeed();
double a1 = one.getAccelerationAngle();
double spinFactor = Math.cos(one.getAccelerationAngle() - two.getAccelerationAngle());
if (!one.isDestroyed()) {
one.setSpeed(two.getSpeed() * FACTOR + one.getSpeed() * (1 - FACTOR));
one.setAccelerationAngle(two.getAccelerationAngle());
one.applySpin(spinFactor);
if (!two.isDestroyed()) {
two.setSpeed(v1 * FACTOR + two.getSpeed() * (1 - FACTOR));
two.setAccelerationAngle(a1);
two.applySpin(-spinFactor);
public Entity[] getVisibleEntities(Entity center) {
return (Entity[]) entities.toArray(new Entity[entities.size()]);
private void initializeStarField() {
stars = new int[MAX_STARS][2];
for (int i = 0; i < MAX_STARS; i++) {
setStar(i);
private void setStar(int index) {
stars[index][0] = Tools.getRandom(STAR_AREA) + STAR_AREA;
stars[index][1] = Tools.getRandom(STAR_AREA) + STAR_AREA;
Finally, the Entity class. All in-game objects extend Entity. Rendering is done in the drawEntity-method. Each Entity has an EntityType which contains parameters like the weight, maximum acceleration and turn rate etc... Images are also stored in EntityType.
public class Entity {
    public static final double TWOPI = Math.PI * 2;
    protected double speed;
    protected double turnRate;
    protected double x, y;
    protected double heading;
    protected double accelerationAngle;
    protected boolean destroyed = false;
    protected double energy;
    protected EntityType type;
    private Equipment activeEquipment;
    private SolarSystem solar;
    public Entity(int xPos, int yPos, EntityType type, SolarSystem solar) {
        this.x = xPos;
        this.y = yPos;
        this.type = type;
        this.energy = this.getEntityType().getEnergy();
        this.solar = solar;
     * Basic entity drawing function doesn't taken rotation into account
    public void drawEntity(int xLocation, int yLocation, Graphics g) {
        if (this.getActiveEquipment() != null && this.getActiveEquipment().isActive()) {
            this.getActiveEquipment().applyEffect(this, g);
//        Level.getHandle().getConsole().addConsoleMessage(xLocation + "x" + yLocation);
        g.drawImage(getIcon(), xLocation, yLocation, null);
    public Shape getBoundingShape() {
        return new Rectangle((int) getX(), (int) getY(), getWidth(), getHeight());