Memory Problem with Java 3D

[eve agostini]

Hi, I'm using an Offscreen Canvas to create an image with Java3D: I render offscreen on an instance of ImageComponent2D, created with a BufferedImage. I need to do that again every time something changes in the model. The problem is that the allocated memory increases every time I render the offscreen canvas for a new rendering, but it never decreases. After a while a get an Out Of Memory exception. If I look at the heap dump there are a lot of ImageComponent2D, ImageComponent2DRetained and RenderedImage objects, which were not deleted.

Here is the piece of code that perform the offscreen rendering:

        
        Dimension dim = new Dimension();
        dim.setSize(1000, 1000);
       
        BufferedImage bImage =
                new BufferedImage(dim.width, dim.height,
                BufferedImage.TYPE_INT_RGB);
        ImageComponent2D buffer =
                new ImageComponent2D(ImageComponent.FORMAT_RGB, bImage);
        offScreenCanvas.setOffScreenBuffer(buffer);
       
        offScreenCanvas.renderOffScreenBuffer();
        offScreenCanvas.waitForOffScreenRendering();
        bImage = offScreenCanvas.getOffScreenBuffer().getImage();
                save (bImage,image); // this method saves the image on file

               
        bImage=null;
        view.removeCanvas3D(offScreenCanvas);
        offScreenCanvas=null;

Thanks for any help
Eve

[August Lammersdorf]

Hi, in my experience it's not easy to get rid of a BufferedImage. In the Java 3D Scala sample program ScCharacterCube (http://www.interactivemesh.org/testspace/j3dmeetsscala.html) it seems to work. Following tips might be helpful:

- Cache and reuse the BufferedImage instance as long as its size or type doesn't change.

- Prevent ImageComponent2D from copying image data by using this constructor
'new ImageComponent2D(myFormat, myWidth, myHeight, true, true)' which creates an instance in 'byReference' and 'yUp'-mode.

- Don't be shy of running the garbage collector (System.gc()) as soon as references are set to null.

Even if the sample is written in Scala see how the object/subclass 'offCanvas3D' in the source code of 'CharacterCubeUniverse.scala' is designed. It includes also the def/method 'flipImageY(bImage: BufferedImage)' to flip your image into 'yDown'-mode.

August, InteractiveMesh

[eve agostini]

Thanks for the advices! Actually I'm giving a try to another 3D lib at the moment, but I'll try to modify my Java3d test following your suggestions.