Jon,
Yes, I've seen this as well with multiple views. My scenario isn't simple
so it's hard to nail down exactly what the problem is, but multiple views
is the key that starts the jitters. I've seen it in TransformGroup objects
which I am modifying or have modified with a mouse drag...
I also have some issues with code that uses
Canvas3D.getCenterEyeInImagePlate(), but I can't say that I have a problem
with that method in particular. It seems that if I use the functions for
ray casting (generatePickRay and pickQuad) I get a VERY jittery effect on a
TransformGroup 'above' the ViewPlatform. This happens with only one
canvas. The idea is that when the mouse is dragged with the right button
down I project a ray onto a plane perpendicular to the view at the location
of the 'selected' object. Over two frames this gives me a delta to move
the viewpoint so I can 'pan' in the view plane relative to an object. I
print out the 3D points that I calculate on that plane each frame an
smoothly run the mouse across the window. I get values that jump pos and
neg and big and small, it may be that the sign is the only thing that gets
flipped but I haven't studied the data enough to say for sure. I'm not
sure why yet, but this 'jitter bug' may have something to do with it...
If I find anything I'll let you know.
Roger
At 06:53 PM 3/2/99 -0800, Jon Barrilleaux wrote:
>I think there is a problem with the J3D computation of the
>view-to-world transformation. I've seen the problem so far in
>Canvas3D.getCenterEyeInImagePlate(), View.getUserHeadToVworld(), and
>and, Node.getLocalToVworld().
>
>What is happening is that the value returned seems to "lag" what the
>ViewPlatform is actually doing, but its not just a simple lag. There
>seems to be a pronounced "jitter" to it; and if the ViewPlatform stops
>moving often the lag will remain until the view-to-world transform is
>read a second time.
>
>Although this is only a guess, perhaps this is related to the problem
>I reported last month (which no one at Sun seemed interested in)
>concerning jitter which occurs when multiple views are used. That
>seemed to be view related also.
>
>Has anyone seen similar problems with any of the view-to-world
>transforms? (I know other people have complained about jitter in
>multiple views.)
>
>--jon
>____________________ Peculiar Technologies ____________________
>Jon Barrilleaux 3800 Lake Shore Ave. Purveyors of
>[EMAIL PROTECTED] Oakland, CA 94610 Alternate Reality
>510.444.4370 voc Augmented Simulation
>510.444.0231 fax www.augsim.com and 3D Solutions
>=====================================================================
>To subscribe/unsubscribe, send mail to [EMAIL PROTECTED]
>Java 3D Home Page: http://java.sun.com/products/java-media/3D/
=====================================================================
To subscribe/unsubscribe, send mail to [EMAIL PROTECTED]
Java 3D Home Page: http://java.sun.com/products/java-media/3D/
