How can I speed up my Java game's FPS?

Question

I am making a Java game, and the game lags a lot when I paint out the graphics. The way I am currently painting out the graphics is to make a BufferedImage, get the Graphics2D from it, then do a whole bunch of:

g2d.drawImage(loadedImages.getImage(),x,y,null);

After I print all of the images to the BufferedImage, I paint the BufferedImage to the screen.

There are a lot of images I paint to the BufferedImage. Is there a better way to do this that would speed up the painting time? I do not know much about graphics and graphic cards. Should I use a graphics card? Should I paint directly to the screen? Should I use something entirely different than drawImage()?

Perhaps it's a good idea to look into OpenGL. You can use it for the same purposes (perhaps with a bit more effort), but it can be accelerated much better than `Graphics2D`. — , Oct 12 '11 at 22:56
I enjoyed using LWJGL (Light Weight Java Game Library, an OpenGL wrapper) directly -- have to write a thin wrapper, but then it's great for 2D ;-) There are other existing game libraries including Slick2D. Java does support *some* 2D acceleration, but I always felt it hit or miss. — , Oct 12 '11 at 22:57
For better help sooner, post an [SSCCE](http://pscode.org/sscce.html). Generate the 'lot of images' in the code. — Andrew Thompson, Oct 12 '11 at 23:07
The only real advantage of using a 'background' image in a double buffered component is if there is a complex scene in it which either does not change, or changes only rarely. — Andrew Thompson, Oct 12 '11 at 23:12

skyuzo · Accepted Answer · 2011-10-12T23:15:06.757

4

The performance should be good if you're drawing a reasonable amount of images.

Make sure you're not creating new BufferedImages every time you draw to the screen. For example, you might have a Resources singleton in which you manage all of your images so that you only load and unload each image once.

If you really want more performance, you'll want to use OpenGL. See LWJGL, libgdx, or JOGL. You may also want to consider 2D graphics libraries like Slick.

edited Oct 12 '11 at 23:15

answered Oct 12 '11 at 22:57

skyuzo

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What is the difference between LWJGL and LibGDX? – Steven Rogers Dec 02 '11 at 00:33
LWJGL is better for desktop development, while libgdx can work on both Android and desktop. – skyuzo Dec 02 '11 at 01:39

score 1 · Answer 2 · answered Feb 08 '17 at 01:53

I've found it useful to extend java.awt.Canvas and use

BufferStrategy bs;
void init() {
    createBufferStrategy(2);// or 3 for triple-buffering
    bs = getBufferStrategy();
}

and then the actual draw() method looks like

void draw() {
    Graphics g = bs.getDrawGraphics();
    g.drawImage(image, x, y, w, h, null);
    // Draw more things here...
    // You can also make calls like `myObject.draw(g)` and whatever
    //    you draw onto `g` within those calls will show up.
    bs.show();
    g.dispose();
}

This is what I use for drawing a lot of things. And then within each myObject.draw(g) call, there are sometimes multiple other similar calls all chained up. Most often my main draw() method has one or two for loops in it that just say for(Entity e: entities) e.draw(g); or something similar. Then the whole drawing chain is kicked off from there.

How can I speed up my Java game's FPS?

2 Answers2