[x3d-public] X3DParticleEmitter node inherit fromX3DChildNode(rather than X3DNode)
Brutzman, Donald (Don) (CIV)
brutzman at nps.edu
Thu Mar 10 18:41:05 PST 2022
Sorry I thought we were talking about Metadata examples, not DEF/USE
id/idref identifier/copy-by-reference kinds of reuse.
BTW am puzzled by glTF example, it looks like "bufferViews" is intended to
point to "buffers" but actually points at something called "buffer" which
does not appear to be defined. Is "buffer" a reserved term for a different
data structure, or a misspelling?
all the best, Don
--
Don Brutzman Naval Postgraduate School, Code USW/Br brutzman at nps.edu
Watkins 270, MOVES Institute, Monterey CA 93943-5000 USA +1.831.656.2149
X3D graphics, virtual worlds, Navy robotics https://
faculty.nps.edu/brutzman
From: Andreas Plesch <andreasplesch at gmail.com>
Sent: Thursday, March 10, 2022 2:29 PM
To: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
Cc: Joseph D Williams <joedwil at earthlink.net>; X3D Graphics public mailing
list <x3d-public at web3d.org>; Jakub Flotyński <flotynski at kti.ue.poznan.pl>
Subject: Re: [x3d-public] X3DParticleEmitter node inherit
fromX3DChildNode(rather than X3DNode)
NPS WARNING: *external sender* verify before acting.
Likely we should create a set of examples from each of the languages you've
listed (and more) to show how to do it.
Here is a start:
- svg
https://developer.mozilla.org/en-US/docs/Web/SVG/Element/defs
<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdeveloper
.mozilla.org%2Fen-US%2Fdocs%2FWeb%2FSVG%2FElement%2Fdefs&data=04%7C01%7Cbrut
zman%40nps.edu%7C71b726f7803c4453578608da02e56444%7C6d936231a51740ea9199f757
8963378e%7C0%7C0%7C637825481566341786%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLj
AwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=SnVCDx91lJ
dcpdtElaeY7q8EuqvklS1%2FtJHE%2BY%2F3IEo%3D&reserved=0>
https://www.w3.org/html/wiki/SVGElements/defs
<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.w3.or
g%2Fhtml%2Fwiki%2FSVGElements%2Fdefs&data=04%7C01%7Cbrutzman%40nps.edu%7C71b
726f7803c4453578608da02e56444%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C6
37825481566341786%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMz
IiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=aUiYIRLUZnwwEQokDtQBjCRKLP0P7t
peqGpnBEfbqX0%3D&reserved=0>
- glTF
https://www.khronos.org/registry/glTF/specs/2.0/glTF-2.0.html#indices-and-na
mes
<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.khron
os.org%2Fregistry%2FglTF%2Fspecs%2F2.0%2FglTF-2.0.html%23indices-and-names&d
ata=04%7C01%7Cbrutzman%40nps.edu%7C71b726f7803c4453578608da02e56444%7C6d9362
31a51740ea9199f7578963378e%7C0%7C0%7C637825481566341786%7CUnknown%7CTWFpbGZs
b3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C300
0&sdata=WXsL2sAj5x5O0qXplpV7fsRW6aR0an0r4X4jKvSmiEw%3D&reserved=0>
by index into a library array
- a-frame
https://aframe.io/docs/1.3.0/core/asset-management-system.html
<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Faframe.io
%2Fdocs%2F1.3.0%2Fcore%2Fasset-management-system.html&data=04%7C01%7Cbrutzma
n%40nps.edu%7C71b726f7803c4453578608da02e56444%7C6d936231a51740ea9199f757896
3378e%7C0%7C0%7C637825481566341786%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwM
DAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=ZSoNXKKQcGNEo
MoE%2FQPJZOY3b2kH%2B4Q2ySULFfyzJ6k%3D&reserved=0>
https://aframe.io/docs/1.3.0/core/mixins.html
<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Faframe.io
%2Fdocs%2F1.3.0%2Fcore%2Fmixins.html&data=04%7C01%7Cbrutzman%40nps.edu%7C71b
726f7803c4453578608da02e56444%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C6
37825481566341786%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMz
IiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=27kABl7V5hTwUd9IjVHXH3zqIsFMfW
FveJettlVdPuo%3D&reserved=0>
- collada
https://www.khronos.org/files/collada_reference_card_1_4.pdf
<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.khron
os.org%2Ffiles%2Fcollada_reference_card_1_4.pdf&data=04%7C01%7Cbrutzman%40np
s.edu%7C71b726f7803c4453578608da02e56444%7C6d936231a51740ea9199f7578963378e%
7C0%7C0%7C637825481566341786%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJ
QIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=vwKXCN5ZEmHLt6mImNr
cCvkoAh0ibEoBgSyhx%2BflXKM%3D&reserved=0> : The library_* elements
(modules)
All of those have examples, except for collada. Perhaps I can collect the
examples and put them onto a wiki page.
Cheers, Andreas
PS: Here is a collada conversion of the simple gltf box at
https://github.com/KhronosGroup/glTF-Sample-Models/blob/master/2.0/Box/glTF/
Box.gltf
<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.co
m%2FKhronosGroup%2FglTF-Sample-Models%2Fblob%2Fmaster%2F2.0%2FBox%2FglTF%2FB
ox.gltf&data=04%7C01%7Cbrutzman%40nps.edu%7C71b726f7803c4453578608da02e56444
%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C637825481566341786%7CUnknown%7
CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0
%3D%7C3000&sdata=QpxauQKjQWMX6h8gkImVz3bBwgWPwIUaSDGglygdFiA%3D&reserved=0>
<?xml version="1.0" encoding="utf-8"?>
<COLLADA version="1.5.0" xmlns="http://www.collada.org/2008/03/COLLADASchema
<https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.collad
a.org%2F2008%2F03%2FCOLLADASchema&data=04%7C01%7Cbrutzman%40nps.edu%7C71b726
f7803c4453578608da02e56444%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C6378
25481566341786%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiL
CJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=Qva0eEoVLsNK7oSp6aq51cMcKFG%2By7X
klLsyYY3PW94%3D&reserved=0> ">
<asset>
<contributor />
<unit meter="1" />
</asset>
<library_lights />
<library_materials>
<material id="Red" name="Red">
<instance_effect url="#effect-Red" />
</material>
</library_materials>
<library_effects>
<effect id="effect-Red" />
</library_effects>
<library_cameras />
<library_geometries>
<geometry id="mesh_1">
<mesh>
<source id="mesh_1-position" name="position">
<float_array id="mesh_1-position-array" count="72">-0.5 -0.5 0.5
0.5 -0.5 0.5 -0.5 0.5 0.5 0.5 0.5 0.5 0.5 -0.5 0.5 -0.5 -0.5 0.5 0.5 -0.5
-0.5 -0.5 -0.5 -0.5 0.5 0.5 0.5 0.5 -0.5 0.5 0.5 0.5 -0.5 0.5 -0.5 -0.5 -0.5
0.5 0.5 0.5 0.5 0.5 -0.5 0.5 -0.5 0.5 0.5 -0.5 -0.5 -0.5 0.5 -0.5 0.5 0.5
-0.5 -0.5 -0.5 -0.5 0.5 -0.5 -0.5 -0.5 -0.5 -0.5 0.5 -0.5 0.5 -0.5 -0.5 0.5
0.5 -0.5 </float_array>
<technique_common>
<accessor source="#mesh_1-position-array" count="24" stride="3">
<param name="X" type="float" />
<param name="Y" type="float" />
<param name="Z" type="float" />
</accessor>
</technique_common>
</source>
<source id="mesh_1-normal" name="normal">
<float_array id="mesh_1-normal-array" count="72">0 0 1 0 0 1 0 0 1
0 0 1 0 -1 0 0 -1 0 0 -1 0 0 -1 0 1 0 0 1 0 0 1 0 0 1 0 0 0 1 0 0 1 0 0 1 0
0 1 0 -1 0 0 -1 0 0 -1 0 0 -1 0 0 0 0 -1 0 0 -1 0 0 -1 0 0 -1 </float_array>
<technique_common>
<accessor source="#mesh_1-normal-array" count="24" stride="3">
<param name="X" type="float" />
<param name="Y" type="float" />
<param name="Z" type="float" />
</accessor>
</technique_common>
</source>
<vertices id="mesh_1-vertices">
<input semantic="POSITION" source="#mesh_1-position" />
</vertices>
<triangles material="default" count="12">
<input semantic="VERTEX" source="#mesh_1-vertices" offset="0" />
<input semantic="NORMAL" source="#mesh_1-normal" offset="1" />
<p>0 0 1 1 2 2 3 3 2 2 1 1 4 4 5 5 6 6 7 7 6 6 5 5 8 8 9 9 10 10
11 11 10 10 9 9 12 12 13 13 14 14 15 15 14 14 13 13 16 16 17 17 18 18 19 19
18 18 17 17 20 20 21 21 22 22 23 23 22 22 21 21</p>
</triangles>
</mesh>
</geometry>
</library_geometries>
<library_images />
<library_visual_scenes>
<visual_scene id="Scene">
<node id="Node--0" sid="Node--0" name="Node #0" type="NODE">
<matrix>1 0 0 0 0 0 1 0 0 -1 0 0 0 0 0 1</matrix>
<node id="Node--1" sid="Node--1" name="Node #1" type="NODE">
<matrix>1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1</matrix>
<instance_geometry url="#mesh_1">
<bind_material>
<technique_common>
<instance_material symbol="mat0" target="#Red" />
</technique_common>
</bind_material>
</instance_geometry>
</node>
</node>
</visual_scene>
</library_visual_scenes>
<library_animations />
<scene>
<instance_visual_scene url="#Scene" />
</scene>
</COLLADA>
Test cases welcome.
all the best, Don
--
Don Brutzman Naval Postgraduate School, Code USW/Br brutzman at nps.edu
<mailto:brutzman at nps.edu>
Watkins 270, MOVES Institute, Monterey CA 93943-5000 USA +1.831.656.2149
X3D graphics, virtual worlds, Navy robotics https://
faculty.nps.edu/brutzman <http://faculty.nps.edu/brutzman>
From: Andreas Plesch <andreasplesch at gmail.com
<mailto:andreasplesch at gmail.com> >
Sent: Thursday, March 10, 2022 1:08 PM
To: Joseph D Williams <joedwil at earthlink.net <mailto:joedwil at earthlink.net>
>
Cc: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu <mailto:brutzman at nps.edu>
>; X3D Graphics public mailing list <x3d-public at web3d.org
<mailto:x3d-public at web3d.org> >
Subject: Re: [x3d-public] X3DParticleEmitter node inherit
fromX3DChildNode(rather than X3DNode)
Good comments.
* MetadataSet to have X3DNode nodes
If I understand it, the idea of ending meta to include actual user code for
the scenegraph is exactly the sort of extension wanting to be "worthwhile to
deviate a bit and be more permissive than the spec" that dooms the long-term
validation operation. Maybe good for something with simple structure that
looks convenient and logical and seemingly convenient to implement at first
thought and elementary usage, then ends up making something definitely not
to be best practice. Please delineate the "worthwhile" parts that make a
case.
I only know that this construction shows up in most of x-ite examples, and
is how the Titania editor saves a scene, simple or complex. I can only
deduce that this decision was deliberate but cannot speak to the specific
motivation by the author. Speculating, the feature seems to be valuable for
authoring. It should be possible to convert to standard x3d automatically by
moving the DEF node from the MetadataSet to the first USE node, perhaps by
xslt.
Not quite sure how validation would be affected.
I agree that Metadata nodes should be limited to actual metadata but a
library node seems sensible.
Here is a list of other, well established scene graph systems which do have
a concept of a non-renderable library which is separate and can then be
referenced as needed:
- svg
- glTF
- a-frame
- collada (I believe)
it is a natural concept and perhaps allows for cleaner user code
organization. Having two alternative ways to define a DEF node (in a
library, and as a first scene graph node) does seem to invite friction, and
would need to be carefully considered.
Andreas
From: Andreas Plesch <mailto:andreasplesch at gmail.com>
Sent: Tuesday, March 8, 2022 11:39 AM
To: Brutzman, Donald (Don) (CIV) <mailto:brutzman at nps.edu>
Cc: X3D Graphics public mailing list <mailto:x3d-public at web3d.org>
Subject: Re: [x3d-public] X3DParticleEmitter node inherit
fromX3DChildNode(rather than X3DNode)
Yes, I am pretty sure Holger is aware. I only brought it up because
Titania/x-ite typically stays very close to the spec. But this is a
capability where Titania/x-ite found it worthwhile to deviate a bit and be
more permissive than the spec. This decision may point to the value of
having a way to DEF any X3DNode (not just child nodes) outside of the scene
graph, outweighing strict compliance.
All the best, Andreas
On Tue, Mar 8, 2022 at 2:22 PM Brutzman, Donald (Don) (CIV)
<brutzman at nps.edu <mailto:brutzman at nps.edu> > wrote:
MetadataSet is only allowed to contain other Metadata* nodes or comments.
Other content will fail validation (and will not load or import in the
X3DJSAIL Java and X3DPSAIL Python libraries).
The right way to cache non-rendered content for DEF/USE libraries is to put
them as children nodes within a Switch node with whichChoice='-1'.
all the best, Don
--
Don Brutzman Naval Postgraduate School, Code USW/Br brutzman at nps.edu
<mailto:brutzman at nps.edu>
Watkins 270, MOVES Institute, Monterey CA 93943-5000 USA +1.831.656.2149
X3D graphics, virtual worlds, Navy robotics https://
faculty.nps.edu/brutzman <http://faculty.nps.edu/brutzman>
From: x3d-public <x3d-public-bounces at web3d.org
<mailto:x3d-public-bounces at web3d.org> > On Behalf Of Andreas Plesch
Sent: Tuesday, March 8, 2022 10:11 AM
To: X3D Graphics public mailing list <x3d-public at web3d.org
<mailto:x3d-public at web3d.org> >
Subject: Re: [x3d-public] X3DParticleEmitter node inherit from
X3DChildNode(rather than X3DNode)
Of note is that Titania and x-ite allow MetadataSet to have X3DNode nodes,
eg. any node, in the value field, not just X3DMetadataObject nodes.
This allows MetadataSet to be used as a NodesLibrary for DEF/USE purposes.
In fact, this kind of redirection is the default setup for scenes created in
Titania.
SVG also has a NodesLibrary equivalent, the <defs> element:
https://developer.mozilla.org/en-US/docs/Web/SVG/Element/defs
<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdeveloper
.mozilla.org%2Fen-US%2Fdocs%2FWeb%2FSVG%2FElement%2Fdefs&data=04%7C01%7Cbrut
zman%40nps.edu%7C71b726f7803c4453578608da02e56444%7C6d936231a51740ea9199f757
8963378e%7C0%7C0%7C637825481566498003%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLj
AwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=fWfdIffjmD
jNN%2FLZkZKXD6XecQj%2BHBAlDBeNhIWI%2BjI%3D&reserved=0>
-Andreas
Date: Mon, 7 Mar 2022 21:29:41 +0100
From: Michalis Kamburelis <michalis.kambi at gmail.com
<mailto:michalis.kambi at gmail.com> >
To: Joseph D Williams <joedwil at earthlink.net <mailto:joedwil at earthlink.net>
>
Cc: GPU Group <gpugroup at gmail.com <mailto:gpugroup at gmail.com> >, "X3D
Public Mailing List
(x3d-public at web3d.org <mailto:x3d-public at web3d.org> )"
<x3d-public at web3d.org <mailto:x3d-public at web3d.org> >
Subject: Re: [x3d-public] X3DParticleEmitter node inherit from
X3DChildNode(rather than X3DNode)
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Perhaps I should have written
"""
The nodes within NodesLibrary don't make any effect, they are not
traversed. They are only to be reUSEd (referenced) by other parts of
the graph."
"""
This makes the wording consistent with how e.g. Switch is described.
Sure you have all the nodes in memory, you just don't traverse to
inactive parts of Switch, LOD, NodesLibrary etc.
Regards,
Michalis
--
Andreas Plesch
Waltham, MA 02453
--
Andreas Plesch
Waltham, MA 02453
--
Andreas Plesch
Waltham, MA 02453
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