Anyway, this solves my problem since I use a constant background color. I
implemented this method in my program. It works.
Thank you very much. I found that this interest group discussion is
particularly useful.
Qiuli Sun
The University of Oklahoma
-----Original Message-----
From: Discussion list for Java 3D API
[mailto:[EMAIL PROTECTED]]On Behalf Of Doug Gehringer
Sent: Friday, December 08, 2000 11:57 AM
To: [EMAIL PROTECTED]
Subject: Re: [JAVA3D] Hidden line problems when using
PolygonAttributes.POLYGON_LINE
> From: Mark Ferneau <[EMAIL PROTECTED]>
>
> Just so that Qiuli understands, I believe the clear side-effect is that
> this only works for objects which are not in front of anything except the
> background.
Correct, this method really mades a solid object with a wireframe
appearance,
not a true hidden-line removed object. MCAD programs used to actually do a
real
hidden line removal, which calcluates the lines that are visible for a given
orientation, but that method is expensive and must be recalculated each time
the
orientation of the object changes.
This method is the practical way to do hidden line removal using modern
hardware, but it has the limitation that the hidden line removed object will
obscure objects behind it (which may be what you want anyway) it will only
match
the background if the background is a constant color.
> Does one also have to disable lighting or set the non-ambient
> values in the material for the filled polygons to be 0,0,0?
Correct. If you look at the example, the solid appearance sets the color,
disables lighting and sets the polygon offset. It also enables back face
culling, which is useful for this example but may not be correct for some
data.
Doug Gehringer
Sun Microsystems
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