Sorry, one more chime in. Kevin, you make it sound like you guys will
fix it if there is enough interest. I think that this is a design flaw
that should be addressed because future J3D prospectors will ask "how do
I optimize", and the answer (in the case of indexed data) will be "you
can't".
I really wish you guys could go open-source on this. J3D has some great
potential, and "little" glitches like this might scare away some
customers. I can't personally do J3D development on my customer's dime,
but it sounds like there are a fair number of ppl (students, etc) that
might be willing to help out.
Okay, that was my $0.02.
-Lee
J. Lee Dixon
SAIC - Celebration, FL
407-566-1438
[EMAIL PROTECTED] AOL: LeeOrlando
> > -----Original Message-----
> > From: Discussion list for Java 3D API
> > [mailto:[EMAIL PROTECTED]]On Behalf Of Kevin Rushforth
> > Sent: Monday, November 06, 2000 11:29 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: [JAVA3D] Memory Issues: same number of normals and
> > coordinate s, even for indexed Geometry?
> >
> > This is a known limitation of the IndexedGeometryArray API. The
> > lengths of the coordinates, colors, normal, texcoord arrays must be
the
> > same even for IndexedGeometryArray objects.
> >
> > We could look into addressing this in Java 3D 1.3, but it will
require
> > additional API, at a minimum separate counts for each of
coordinates,
> > colors, normal, texcoord. It will also require significant changes
to
> > the implementation; currently, all of the set/get methods for vertex
> > data are in the GeometryArray base class. These would either have
to
> > be modified to know about the separate counts for each component or
> > they would have to be overridden in the IndexedGeometryArray class.
If
> > there is enough demand for this, we could look into doing it (at
least
> > for the by-ref case).
> >
> > --
> > Kevin Rushforth
> > Java 3D Team
> > Sun Microsystems
> >
> > [EMAIL PROTECTED]
> >
> > >Date: Mon, 6 Nov 2000 08:22:10 -0500
> > >From: "J. Lee Dixon" <[EMAIL PROTECTED]>
> > >Subject: Re: [JAVA3D] Memory Issues: same number of normals
and
> > coordinate
> > > s,
> > > even for indexed Geometry?
> > >To: [EMAIL PROTECTED]
> > >
> > >Yep, I can definitely agree with you there. If you are using an
> > >IndexedGeometryArray subclass, it would make sense to be able to
have
> > >multiple faces that point the same direction (i.e. share the same
> > >normal).
> > >
> > >Yet, the API spec says that if your normals.length <
(3*vertexcount),
> > >you will get an exception. This makes no sense for indexing.
> > >
> > >Can somebody at Sun PLEASE address this design issue???
> > >
> > >-Lee
> > >
> > >-----Original Message-----
> > >From: Adam Tegen [mailto:[EMAIL PROTECTED]]
> > >Sent: Friday, November 03, 2000 5:34 PM
> > >To: [EMAIL PROTECTED]
> > >Subject: Re: [JAVA3D] Memory Issues: same number of normals and
> > >coordinate s, even for indexed Geometry?
> > >
> > >
> > >Thanks very much for the reply.
> > >
> > >One thing though:
> > >
> > >I am using setNormalRefFloat(), so in this example I have to create
> > >
> > >float[] locations = new float[24];
> > >float[] normals = new float[24]; //not 18, because its by ref.
> > >
> > >so I waste the space for 6 floats (4 bytes each) for 24 bytes.
> > >
> > >Since I am doing cad data, dealing with possibly hundreds of megs
of
> > >data,
> > >this wasted space can amount to a lot.
> > >
> > >If anyone at sun could chime in, I would appreciate it. The part I
> > >don't
> > >understand is why there is this issue in the first place. Indexed
data
> > >shouldn't care, unless I am missing something. XSG, for instance,
> > >doesn't
> > >care.
> > >
> > >Thanks much,
> > >
> > >Adam
> > >
> > >
> > >-----Original Message-----
> > >From: Discussion list for Java 3D API
> > >[mailto:[EMAIL PROTECTED]]On Behalf Of J. Lee Dixon
> > >Sent: Friday, November 03, 2000 4:55 PM
> > >To: [EMAIL PROTECTED]
> > >Subject: Re: [JAVA3D] Memory Issues: same number of normals and
> > >coordinate s, even for indexed Geometry?
> > >
> > >
> > >Each "vertex" has a location (or coordinate), and optionally a
normal,
> > >color, and texture coordinate.
> > >
> > >After looking at the API specs for IndexedGeometryArray, I think it
> > >works like this (somebody at Sun feel free to chime in):
> > >
> > >Vector3d[] locations = new Vector3d[8] { ... 8 locations ... };
> > >Vector3d[] normals = new Vector3d[6] { ... 6 normals ... };
> > >
> > >int index_count = 4 (vertices_per_face) * 6 (faces) = 24;
> > >cube = new IndexedQuadArray(locations.length, COORDINATES |
NORMALS,
> > > index_count);
> > >
> > >// Now, set the locations.
> > >cube.setCoordinates(0, locations);
> > >
> > >// Now, set the normals. I think what happens here is that
> > >// the GeometryArray has allocated space for *pointers* to 8
normals,
> > >// but we only fill 6 of them.
> > >cube.setNormals(0, normals)
> > >
> > >int[] location_indices = new int[index_count]
> > >{
> > > 0, 1, 2, 3, // the quad for the first face,
> > > 1, 3, 7, 4, // the quad for the second face,
> > > 5, 4, 7, 6, // the quad for the third face,
> > > etc....
> > >};
> > >
> > >int[] normal_indices = new int[index_count]
> > >{
> > > 0, 0, 0, 0, // the normals for the vertices in the first face
are the
> > >same
> > > 1, 1, 1, 1, // second face
> > > 2, 2, 2, 2, // third face
> > > 3, 3, 3, 3, // etc...
> > > 4, 4, 4, 4,
> > > 5, 5, 5, 5
> > >};
> > >
> > >So, I think the only *wasted* space is the two normal pointers in
the
> > >normal array that are not used... Does this sound right to ppl at
> > >Sun?????
> > >The GeometryArray is (hopefully) allocating the array space, but
not the
> > >actual members of the normal array. I mean:
> > >
> > > // They have to do this because the max possible normals the
> > > // user will want is a normal for each vertex.
> > > myNormals = new Vector3d[vertex_count];
> > >
> > > // But hopefully not doing this:
> > > int i;
> > > for(i=0; i<myNormals.length; i++)
> > > {
> > > myNormals[i] = new Vector3d();
> > > }
> > >
> > >*whew*
> > >-Lee
> > >
> > >-----Original Message-----
> > >From: Adam Tegen [mailto:[EMAIL PROTECTED]]
> > >Sent: Friday, November 03, 2000 2:18 PM
> > >To: [EMAIL PROTECTED]
> > >Subject: Re: [JAVA3D] Memory Issues: same number of normals and
> > >coordinate s, even for indexed Geometry?
> > >
> > >
> > >A further question:
> > >
> > >A "Vertex" is a combination of coordinate, normal, etc. right? If
you
> > >have
> > >an IndexedGeometryArray, why does the number of normals need to
equal
> > >the
> > >number of coordinates? The number of indices for each does need to
be
> > >the
> > >same for each, though.
> > >
> > >Can you explain this to me further? Other scene graphs use
per-vertex
> > >shading and do not have this restriction.
> > >
> > >Adam
> > >
> > >-----Original Message-----
> > >From: Discussion list for Java 3D API
> > >[mailto:[EMAIL PROTECTED]]On Behalf Of J. Lee Dixon
> > >Sent: Friday, November 03, 2000 1:28 PM
> > >To: [EMAIL PROTECTED]
> > >Subject: Re: [JAVA3D] Memory Issues: same number of normals and
> > >coordinate s, even for indexed Geometry?
> > >
> > >
> > >The reason for the number of normals equalling the number of
coordinates
> > >is that Java3D does per-vertex shading. This allows for smooth
shading
> > >of curved surfaces, but yes it is a little wasteful for objects
like
> > >cubes.
> > >
> > >-Lee
> > >
> > >-----Original Message-----
> > >From: Adam Tegen [mailto:[EMAIL PROTECTED]]
> > >Sent: Friday, November 03, 2000 12:11 PM
> > >To: [EMAIL PROTECTED]
> > >Subject: [JAVA3D] Memory Issues: same number of normals and
coordinates,
> > >even for indexed Geometry?
> > >
> > >
> > >Hello-
> > >
> > >I'm doing some tests with Java3D and notices something:
> > >
> > >The number of coordinates must equal the number of normals (when
> > >enabled)
> > >etc. At least this is how it seems to be when I use commands like
> > >IndexedTriangleArray.setNormalRefFloat(...)
> > >
> > >While this makes sense for non-indexed geometry, how does this make
> > >sense
> > >for indexed geometry? A cube, for instance has 8 coordinates, and
6
> > >normals.
> > >
> > >Am I understanding this correctly? Does this mean that java3D eats
up
> > >unneeded memory? Is there a good reason for this, or is this an
area
> > >for
> > >improvement for future versions.
> > >
> > >If someone could explain this to me, I would greatly appreciate it.
> > >
> > >Adam
> > >
> >
>=======================================================================
=
> > >===
> > >To unsubscribe, send email to [EMAIL PROTECTED] and include in
the
> > >body
> > >of the message "signoff JAVA3D-INTEREST". For general help, send
email
> > >to
> > >[EMAIL PROTECTED] and include in the body of the message
"help".
> > >
> >
>=======================================================================
=
> > >===
> > >To unsubscribe, send email to [EMAIL PROTECTED] and include in
the
> > >body
> > >of the message "signoff JAVA3D-INTEREST". For general help, send
email
> > >to
> > >[EMAIL PROTECTED] and include in the body of the message
"help".
> > >
> >
>=======================================================================
=
> > >===
> > >To unsubscribe, send email to [EMAIL PROTECTED] and include in
the
> > >body
> > >of the message "signoff JAVA3D-INTEREST". For general help, send
email
> > >to
> > >[EMAIL PROTECTED] and include in the body of the message
"help".
> > >
> >
>=======================================================================
=
> > >===
> > >To unsubscribe, send email to [EMAIL PROTECTED] and include in
the
> > >body
> > >of the message "signoff JAVA3D-INTEREST". For general help, send
email
> > >to
> > >[EMAIL PROTECTED] and include in the body of the message
"help".
> > >
> >
>=======================================================================
=
> > >===
> > >To unsubscribe, send email to [EMAIL PROTECTED] and include in
the
> > >body
> > >of the message "signoff JAVA3D-INTEREST". For general help, send
email
> > >to
> > >[EMAIL PROTECTED] and include in the body of the message
"help".
> > >
> >
>=======================================================================
> ====
> > >To unsubscribe, send email to [EMAIL PROTECTED] and include in
the
> body
> > >of the message "signoff JAVA3D-INTEREST". For general help, send
email to
> > >[EMAIL PROTECTED] and include in the body of the message
"help".
> > >
> >
> >
========================================================================
===
> > To unsubscribe, send email to [EMAIL PROTECTED] and include in
the body
> > of the message "signoff JAVA3D-INTEREST". For general help, send
email to
> > [EMAIL PROTECTED] and include in the body of the message "help".
> >
> >
========================================================================
===
> > To unsubscribe, send email to [EMAIL PROTECTED] and include in
the body
> > of the message "signoff JAVA3D-INTEREST". For general help, send
email to
> > [EMAIL PROTECTED] and include in the body of the message "help".
>
>=======================================================================
====
>To unsubscribe, send email to [EMAIL PROTECTED] and include in the
body
>of the message "signoff JAVA3D-INTEREST". For general help, send email
to
>[EMAIL PROTECTED] and include in the body of the message "help".
Mark Ferneau 240-462-6262 (cell)
Director of Adv. Technology 801-437-4608 (efax)
Xtivia Technologies, Inc. 732-469-5954 x629 (NJ office)
[EMAIL PROTECTED] 301-279-5703 (home office)
http://www.xtivia.com/ [EMAIL PROTECTED] (wireless email)
========================================================================
===
To unsubscribe, send email to [EMAIL PROTECTED] and include in the
body
of the message "signoff JAVA3D-INTEREST". For general help, send email
to
[EMAIL PROTECTED] and include in the body of the message "help".
========================================================================
===
To unsubscribe, send email to [EMAIL PROTECTED] and include in the
body
of the message "signoff JAVA3D-INTEREST". For general help, send email
to
[EMAIL PROTECTED] and include in the body of the message "help".
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff JAVA3D-INTEREST". For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
