R. Carassou wrote:
Hi all
I have to Behavior attach to my Universe with
apparently the same wakeUp Condition
a OrbitBehavior and a other behavior (see the code
below)
sometime a Exception is throwed, and I it's difficult
to clearly define the bug context.
is it a Behavior scheduling problem ?a OrbitBehavior
bug? or i' m doing something wrong in my own behavior?
thanks in advance for yours advices
Regards
renaud
Exception occurred during Behavior execution:
javax.media.j3d.BadTransformException: non-congruent
transform above ViewPlatform
at
javax.media.j3d.TransformGroupRetained.setTransform(TransformGroupRetained.java:138)
at
javax.media.j3d.TransformGroup.setTransform(TransformGroup.java:111)
at
prm3d.behavior.OrbitBehavior.integrateTransforms(OrbitBehavior.java:482)
at
prm3d.behavior.ViewPlatformAWTBehavior.processStimulus(ViewPlatformAWTBehavior.java:249)
at
javax.media.j3d.BehaviorScheduler.doWork(BehaviorScheduler.java:172)
at
javax.media.j3d.J3dThread.run(J3dThread.java:250)
The OrbitBehavior in your own prm3d package pass non-congruent transform
to J3D.
This is most likely cause by numerically imprecision that when matrix
rotate/scale/invert
operation accumulate for a while the matrix become non-congruent.
To workaround catch this Exception (or check for it use Transform3D
getType()
before setTransform() above ViewPlatform) and reset/renormalize the
Transform3D
using Transform3D
/**
* Normalizes the rotational components (upper 3x3) of this matrix
* in place using a Singular Value Decomposition (SVD).
* This operation ensures that the column vectors of this matrix
* are orthogonal to each other. The primary use of this method
* is to correct for floating point errors that accumulate over
* time when concatenating a large number of rotation matrices.
* Note that the scale of the matrix is not altered by this method.
*/
public final void normalize()
- Kelvin
---------------
Java 3D Team
Sun Microsystems Inc.
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