Java2D Performance Issues

I think I found a solution by researching and putting bits and pieces together from too many Google searches.

Here it is, comments and all:

private BufferedImage toCompatibleImage(BufferedImage image)
{
    // obtain the current system graphical settings
    GraphicsConfiguration gfxConfig = GraphicsEnvironment.
        getLocalGraphicsEnvironment().getDefaultScreenDevice().
        getDefaultConfiguration();

    /*
     * if image is already compatible and optimized for current system 
     * settings, simply return it
     */
    if (image.getColorModel().equals(gfxConfig.getColorModel()))
        return image;

    // image is not optimized, so create a new image that is
    BufferedImage newImage = gfxConfig.createCompatibleImage(
            image.getWidth(), image.getHeight(), image.getTransparency());

    // get the graphics context of the new image to draw the old image on
    Graphics2D g2d = newImage.createGraphics();

    // actually draw the image and dispose of context no longer needed
    g2d.drawImage(image, 0, 0, null);
    g2d.dispose();

    // return the new optimized image
    return newImage; 
}

In my previous post, GraphicsConfiguration was what held the information needed to create optimized images on a system. It seems to work pretty well, but I would have thought Java would automatically do this for you. Obviously you can't get too comfortable with Java. :) I guess I ended up answering my own question. Oh well, hopefully it'll help some of you I've seen trying to make use of Java for 2D games.

Well, this is old post but I'd like to share my findings about direct drawing with Swing/AWT, without BufferedImage.

Some kind of drawing, as 3D, are better done when painting directly to a int[] buffer. Once done the images, you can use an ImageProducer instance, like MemoryImageSource, to produce images. I'm assuming you know how to perform your drawings directly, without help of Graphics/Graphics2.

    /**
* How to use MemoryImageSource to render images on JPanel
* Example by A.Borges (2015)
*/
public class MyCanvas extends JPanel implements Runnable {

public int pixel[];
public int width;
public int height;
private Image imageBuffer;   
private MemoryImageSource mImageProducer;   
private ColorModel cm;    
private Thread thread;


public MyCanvas() {
    super(true);
    thread = new Thread(this, "MyCanvas Thread");
}

/**
 * Call it after been visible and after resizes.
 */
public void init(){        
    cm = getCompatibleColorModel();
    width = getWidth();
    height = getHeight();
    int screenSize = width * height;
    if(pixel == null || pixel.length < screenSize){
        pixel = new int[screenSize];
    }        
    mImageProducer =  new MemoryImageSource(width, height, cm, pixel,0, width);
    mImageProducer.setAnimated(true);
    mImageProducer.setFullBufferUpdates(true);  
    imageBuffer = Toolkit.getDefaultToolkit().createImage(mImageProducer);        
    if(thread.isInterrupted() || !thread.isAlive()){
        thread.start();
    }
}
/**
* Do your draws in here !!
* pixel is your canvas!
*/
public /* abstract */ void render(){
    // rubisch draw
    int[] p = pixel; // this avoid crash when resizing
    if(p.length != width * height) return;        
    for(int x=0; x < width; x++){
        for(int y=0; y<height; y++){
            int color =  (((x + i) % 255) & 0xFF) << 16; //red
                color |= (((y + j) % 255) & 0xFF) <<  8; //green
                color |= (((y/2 + x/2 - j) % 255) & 0xFF) ;   //blue         
            p[ x + y * width] = color;
        }
    }        
    i += 1;
    j += 1;          
}    
private int i=1,j=256;

@Override
public void run() {
    while (true) {
        // request a JPanel re-drawing
        repaint();                                  
        try {Thread.sleep(5);} catch (InterruptedException e) {}
    }
}

@Override
public void paintComponent(Graphics g) {
    super.paintComponent(g);
    // perform draws on pixels
    render();
    // ask ImageProducer to update image
    mImageProducer.newPixels();            
    // draw it on panel          
    g.drawImage(this.imageBuffer, 0, 0, this);  
}

/**
 * Overrides ImageObserver.imageUpdate.
 * Always return true, assuming that imageBuffer is ready to go when called
 */
@Override
public boolean imageUpdate(Image image, int a, int b, int c, int d, int e) {
    return true;
}
}// end class

Note we need unique instance of MemoryImageSource and Image. Do not create new Image or new ImageProducer for each frames, unless you have resized your JPanel. See init() method above.

In a rendering thread, ask a repaint(). On Swing, repaint() will call the overridden paintComponent(), where it call your render() method and then ask your imageProducer to update image. With Image done, draw it with Graphics.drawImage().

To have a compatible Image, use proper ColorModel when you create your Image. I use GraphicsConfiguration.getColorModel():

/**
 * Get Best Color model available for current screen.
 * @return color model
 */
protected static ColorModel getCompatibleColorModel(){        
    GraphicsConfiguration gfx_config = GraphicsEnvironment.
            getLocalGraphicsEnvironment().getDefaultScreenDevice().
            getDefaultConfiguration();        
    return gfx_config.getColorModel();
}

From what I remember when I was thinking about doing graphics programming in Java, the built in libraries are slow. I was advised on GameDev.Net that anyone doing anything serious would have to use something like jogl