Re: The random colour changing bug

• To: Curtis Rueden <ctrueden@xxxxxxxx>
• Subject: Re: The random colour changing bug
• From: Bill Hibbard <billh@xxxxxxxxxxxxx>
• Date: Mon, 21 Nov 2005 12:27:57 -0600 (CST)

Hi Curtis,

> I tried it on my machine (Linux running Java 1.4.2_09 and Java3D 1.3.1
> with an nVidia graphics card), and saw the bug. The yellow box gets
> slightly darker once the middle button is pressed and the cursor is
> moved at all.
>
> I tried a few other tests. The problem occurs regardless of texture
> mapping on or off. It does not occur with Java2D, or with a color
> mapping to RGB instead of ConstantMaps to Red, Green and Blue. I've
> included a modified version of the test program that uses a mapping to
> Display.RGB to avoid the problem.

Thanks for these experiments. It sounds like a
Java3DD problem, but one that we may be able to
avoid by some small change.

> Bill, any ideas how I could continue investigating this issue? I can
> just dig into the ConstantMap logic, since that seems likely. The fact
> that you aren't seeing the problem on your machine suggests that it's
> either specific to newer versions of Java3D, or dependent on graphics
> card hardware.

You might try my Bounds suggestion, but I doubt
that will fix the problem. I used your modified
version of Andrew's test program to see if there
were any differences in the calls to staticMakeAppearance()
in visad/java3d/ShadowTypeJ3D.java between the
ConstantMap to color and the ScalarMap to RGB.
But as far as I could tell, in both cases the
ColoringAttributes argument was null, the
TransparencyAttributes argument was generated
from alpha = 0.0, and no_material was false. I
guess the thing to do is to determine what could
be different between the ConstantMap case and the
ScalarMap to RGB case, in either the GeometryArray
or the Appearance.

Cheers,
Bill

• References:
  • Re: The random colour changing bug
    • From: Curtis Rueden