Thank you very much for the answers :)

Dave Yazel

----- Original Message -----
From: Uma Sabada <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, June 19, 2001 12:17 PM
Subject: Re: [JAVA3D] GeometryUpdater and ByRef geometry


> 1. Does by-ref geometry get sent over to the card every frame even if a
> GeometryUpdater has not been used to change it?
> 2. If so, why?  Since it the only time you are supposed to update the
> geometry is inside the GeometryUpdater, which you have knowledge of.  Is
it
> because you don't put it into a DisplayList assuming it might be
frequently
> changed?  Is there advantage in frames where you *didn't* make a change?

Java3D currently *always* uses Vertex Array to render geometry by-reference
and
therefore the geometry will be sent down every frame. In future, we are
contemplating an API by which application can tell Java3D the
memory/performance trade-off as well as "very infrequently changed" hint.
These
hints will help us determine whether to use display list or VertexArray.

>Is there advantage in frames where you *didn't* make a change?

There are some advantages if you didn't make a change. For example, if any
of
the Shape3D that use this geometry have autoBoundsCompute set to "true",
then
boundingBox of this geometry will be computed every time you change the
geometry and if you are using non-basic types such as Point3f there is
additional work that is done everytime you change the geometry data.


> 3. Is the GeometryUpdater run at the same time and in the same thread as
the
> one invoking updateData()?  Is it guarenteed to be processed in the same
> frame as all the other scene changes done in the same behavior?
>
All changes made through a behavior are guaranteed to be processed in the
same
frame.


-Uma




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> Date: Mon, 18 Jun 2001 19:51:27 -0400
> From: David Yazel <[EMAIL PROTECTED]>
> Subject: [JAVA3D] GeometryUpdater and ByRef geometry
> To: [EMAIL PROTECTED]
>
> Couple of questions for the Sun folks:
>
> 1. Does by-ref geometry get sent over to the card every frame even if a
> GeometryUpdater has not been used to change it?
>
> 2. If so, why?  Since it the only time you are supposed to update the
> geometry is inside the GeometryUpdater, which you have knowledge of.  Is
it
> because you don't put it into a DisplayList assuming it might be
frequently
> changed?  Is there advantage in frames where you *didn't* make a change?
>
> 3. Is the GeometryUpdater run at the same time and in the same thread as
the
> one invoking updateData()?  Is it guarenteed to be processed in the same
> frame as all the other scene changes done in the same behavior?
>
> 4. If the answer to the above is no, then how would you make absolutely
sure
> that two different by-ref geometries can be correctly updated within the
> same frame?
>
> Sincerely,
>
> Dave Yazel
>
>
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