Eric,
You wrote:
>Hi.
>If I have multiple ViewPlatforms and multiple Views, one View on each
>different
>view platform, but all in one Locale, is behaviour going
>to work properly in all the views, or not?
>
>For example, the logically correct way for a DistanceLOD to
>work would be to render for each view the appropriate level of detail,
>depending on the distance of each of those views, respectively,
>from the LOD node. Is this what happens?
>
>The presence of the getView() method of Behavior
>Defn: "Returns the primary view of the behaviour"
>makes me suspicious that behaviours will only work properly for
>one view per locale. Is this true?
>
>What's the true situation here in Java3D? This has major consequences on
>ability
>to do multi-POV (multi-agent) virtual worlds properly.
>
>Eric
>
You've seen the problem with implementing such things via Behaviors!
One of the (few) things which Java3D has VERY wrong - the basic problem is
that some things are global when they should be local to views. This
problem doesn't appear in VRML, as you have one "view" per browser.
To quote from an email of February 1998:
***********************************************************************
An issue has been raised as to how multiple views are handled with LOD
and with Billboard behavior. As has been pointed out, the fact that
Billboard and LOD are behaviors that operate on the scene graph makes
it difficult to support multiple views, each with a different
orientation or level of detail.
We realize that this is a hole in the current design and have added
the following new method to the Behavior node object to address this
issue.
protected View getView()
Returns the primary view associated with this behavior. This
method is useful with certain types of behaviors (e.g.,
Billboard, LOD) that rely on per-View information and with
behaviors in general in regards to scheduling (the distance
from the view platform determines the active behaviors). The
"primary" view is defined to be the first View attached to a
live ViewPlatform, if there is more than one active View. So,
for instance, Billboard behaviors would be oriented toward this
primary view, in the case of multiple active views into the
same scene graph.
This method will be part of the impending public early access release.
We will be releasing an updated API specification at the same time.
Subsequent versions of the API will address the issue of providing
more complete support for multiple views, but the current version is
somewhat limited in this respect.
Hope this helps.
--
Kevin Rushforth
Java 3D Team
Sun Microsystems
***********************************************************************
Oh well! Can't have everything, can we?
All the best,
Anthony
******************************************
Imperium Computing Consultants Ltd.
Web and Database solutions at
http://www.imperium.co.uk/
******************************************
=====================================================================
To subscribe/unsubscribe, send mail to [EMAIL PROTECTED]
Java 3D Home Page: http://java.sun.com/products/java-media/3D/
