Hi John,
don't know whether this helps you:
my ImageRenderCanvas works for rendering offscreen images, using a seprate
Thread (see attachment). It worked under win2k 1.21 and 1.3 beat 1,2 and
under linux with 1.2.1 with -Dj3d.sharedctx=false option (bad performance).
unfortunally there is another bug with the perspective (Mark from Java3D team
told me, he submitted it), but in case your onscreen canvas is of a squared
dimension it worked fine for me..
regards
-Michael
On Thursday 27 June 2002 20:26, John Barrus wrote:
> Kelvin,
>
> Is there no workaround right now? I don't mind rebuilding part of the
> scene graph or something if I need to.
>
> Do you know anything about the trigger? It seems like it just started
> happening a week ago, but I made several changes and I'm not sure which
> ones might have affected it.
>
> Sincerely,
>
> John B.
>
>
> -----Original Message-----
> From: Discussion list for Java 3D API
> [mailto:[EMAIL PROTECTED]] On Behalf Of Kelvin Chung
> Sent: Thursday, June 27, 2002 10:49 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [JAVA3D] Problems with off-screen rendering
>
>
> Hi John,
>
> This is bug 4701430 -
> Infrequent NPE at RenderBin.java:544
>
> which has a workaround in the upcoming v1.3 release.
>
> - Kelvin
> ----------------
> Java 3D Team
> Sun Microsystems Inc.
>
> >Date: Thu, 27 Jun 2002 09:43:41 -0700
>
> From: John Barrus <[EMAIL PROTECTED]>
>
> >Subject: [JAVA3D] Problems with off-screen rendering
> >To: [EMAIL PROTECTED]
> >MIME-version: 1.0
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> >
> >I have an application that renders to an image offscreen and then
>
> combines
>
> >the rendered image with a photograph. Unfortunately, there are times
>
> when
>
> >the render thread dies and I get the following error:
> >
> >java.lang.NullPointerException
> > at javax.media.j3d.RenderBin.updateObject (RenderBin.java:544)
> > at javax.media.j3d.MasterControl.updateMirrorObjects
> >(MasterControl.java:2633)
> > at javax.media.j3d.MasterControl.runMonitor
> >(MasterControl.java:3321)
> > at javax.media.j3d.MasterControl.doWork
>
> (MasterControl.java:2890)
>
> > at javax.media.j3d.MasterControlThread.run
> >(MasterControlThread.java:28)
>
> From then on, I cannot render any more. I get the following
>
> >error every time I try to render the image again:
> >
> >javax.media.j3d.RestrictedAccessException: Canvas3D: Off-
> >screening rendering is in progress
> > at javax.media.j3d.Canvas3D.renderOffScreenBuffer
> >(Canvas3D.java:1868)
> > at app.MeshRenderer.getImage(MeshRenderer.java:716)
> > at app.PerspectiveGrid$ImageThread.run
>
> (PerspectiveGrid.java:805)
>
> >I figured out how to detect the error, but I can't figure out how to
>
> restart
>
> >the renderer. I get an error when I try to apply stopRenderer() or
> >startRenderer() to the Canvas3D.
> >
> >Any suggestions?
> >
> >I filed a bug report with Sun.
> >
> >John Barrus
> >
> >=======================================================================
>
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>
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import java.awt.GraphicsConfiguration;
import java.awt.image.BufferedImage;
import javax.media.j3d.*;
/**
*
* @author zero
*/
public class ImageRenderCanvas3D extends Canvas3D {
private BufferedImage buffer;
private boolean printing = false;
private boolean started = false;
/** Creates a new instance of OffCanvas3D */
public ImageRenderCanvas3D(java.awt.GraphicsConfiguration graphicsConfiguration, BufferedImage buffer) {
super(graphicsConfiguration, true);
this.buffer = buffer;
int width = buffer.getWidth();
int height = buffer.getWidth();
BufferedImage bImage = new BufferedImage(
width, height , BufferedImage.TYPE_INT_ARGB);
ImageComponent2D imgBuffer = new ImageComponent2D(
ImageComponent.FORMAT_RGBA, bImage);
imgBuffer.setCapability(ImageComponent2D.ALLOW_IMAGE_READ);
buffer.setCapability(ImageComponent2D.ALLOW_IMAGE_WRITE);
this.setOffScreenBuffer(imgBuffer);
}
public void start() {
if(!started) {
new Ready().start();
started = true;
}
}
public void postSwap() {
super.postSwap();
drawOffScreenBuffer();
}
private void drawOffScreenBuffer() {
BufferedImage bImage = this.getOffScreenBuffer().getImage();
buffer.getGraphics().drawImage(bImage, 0, 0, this);
}
private class Ready extends Thread {
public void run() {
while(true) {
waitForOffScreenRendering();
}
}
}
}
