Java 2D Game drawing performance

Question

I created a 2D game in java and am trying to get it to 60 fps with a resolution of 1920x1080 pixels. My game logic is performing fine in less than 1 millisecond. But the drawing takes up to over 10 milliseconds. This might be sufficient on my rather strong desktop (intel i5-4670K @ 3.40 Ghz), but on my laptop (intel i5-6300HQ @2.30 Ghz) the game is already slowing down quite a bit. The drawing is separated into two main steps:

draw every component of the game onto a BufferedImage
draw the BufferedImage in my extended JPanel class

The corresponding code is this:

@Override
public void run() {

    init();

    long startTime;
    long elapsedTime;
    long waitTime;

    while(running) {

        startTime = System.nanoTime();

        update();
        long updateTime = (System.nanoTime() - startTime) / 1000000;
        draw();
        long drawTime = (System.nanoTime() - startTime) / 1000000;
        drawToScreen();
        long drawscreenTime = (System.nanoTime() - startTime) / 1000000;

        elapsedTime = System.nanoTime() - startTime;
        waitTime = targetTime - elapsedTime / 1000000;
        if(waitTime < 0) {
            waitTime = 0;
        }

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

public void init() {

    GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();
    GraphicsDevice device = env.getDefaultScreenDevice();
    GraphicsConfiguration config = device.getDefaultConfiguration();
    image = config.createCompatibleImage(1920, 1080, Transparency.TRANSLUCENT);

    g2d = (Graphics2D) image.getGraphics();
    running = true;
    gsm = new GameStateManager(this);
}

public void update() {
    gsm.update();
    Keys.update();
}

public void draw() {
    gsm.draw(g2d);
}

public void drawToScreen() {
    Graphics g = getGraphics();
    g.drawImage(image, 0, startDrawY, scaledWidth, scaledHeight, null);
    g.dispose();
}

Both the draw and drawToScreen methods take up to 5 milliseconds. inside the draw method, the slowest parts are drawing the background image (1920x1080 image) and drawing the level (consisting of several 135x135 images), which both take a few milliseconds.

Now i have two questions: Is this draw-speed normal for large images like that? And if not what might I be doing wrong here or how can I improve the drawing-performance?

Java 2D Game drawing performance

1 Answers