VolatileImage vs. Automatic Images or something.

Java 2D
#1

I’ve seen a lot about ‘Automatic Images’ . . . I think that’s the term, but all these discussions seem to be long-running ones so I’m not sure I follow it.

Basically from what I understand this . . .


BufferedImage autoImage=gc.createCompatibleImage(width,height);

. . . creates an image which is hardware accelerated, provided I don’t modify it in any way. If I paste anything onto it with . . .


Graphics2D g2 = autoImage.createGraphics();
g2.drawImage(someImage,x,y,null);

. . . makes it so it’s not hardware accellerated. Is that right, or am I off somewhere?

I’m not doing it this way ATM. I’m using BufferedImages to hold raw images so that I can composite them and still preserve any transparency. So I take and composite them all onto a VolatileImage. If the contents change, or I lose the contents of the VolatileImage, I rebuild the background, but as it happens so infrequently, each refresh I’m just pasting the VolatileImage Background . . . for sure accellerated . . . and slapping foreground stuff on top of it. (don’t need transparency for that stuff yet.)

The reason I ask is that I’m hitting a slow framerate and I think it’s 'cause I’m doing something wrong. I’m trying to figure out if using these ‘automatic images’ might be faster, or if I might be hitting a bottleneck somewhere I don’t know about.

So . . . here’s a rough outline of the code I’m using.


public class ContentWindow extends Component
{
  VolatileImage myBG;
  
  private void buildBG()
  {
    Graphics2D g2=myBG.createGraphics();
    //Bunch of draw operations
    g2.dispose();
  }

  public void render(Graphics2D g2)
  {
    if(myBG.contentsLost())
    {
           buildBG();
    }
    g2.drawImage(myBG,getX(),getY(),null);
    g2.setColor(Color.yellow);
    g2.fillRect(mouseX-5,mouseY-5,mouseX+5,mouseY+5);
  }
}

Right now, this component is 640x430 . . . running in windowed mode, and it’s the ONLY component being redrawn. I’ve limited the framerate to 20 refreshes per second and STILL it chunks every half-second or so. Is there something I’m doing wrong here? Some way to optimize this?

I’m running on some sort of P3 (not sure what) a TON of memory, but a piece of crap graphics card. Still . . . not doing anything OVERLY taxing. Anybody with advice, I’d be more than happy to hear it.

#2

the chunk is most likely the GC kicking in. profile your code to see where you create a lot of garbage.

#3

What version of JVM are you using? Garbage collection pauses have become pretty much unnoticeable in 1.4, unless you are creating really huge amounts of garbage.

Also, if you have a lot of large textures out then you could be suffering from texture swapping on the video card. How much video memory do you have and how big and/or numerous are your textures?

#4

JVM version is . . . 1.4.2beta

Memory on card is . . . I think 16MB, but it’s a POS card. Right now I’m using a 640x430 VolatileImage, a 640x50 VolatileImage and three 30X30 VolatileImages.

That’s it. Really, it should be able to handle that much, I would think. I dunno . . . another thing I noticed. There’s only one chunk when I run it in fullscreen mode then it’s smooth at 30 fps after that.

sigh I’m stumped.