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<div class="moz-cite-prefix">Hi,<br>
<br>
+1 for Cecile's proposal with explicit containers.<br>
<br>
Two remarks:<br>
- I think there shouldn't be a default type. Otherwise an
application needs to know these default values, which again makes
it harder to implement tools.<br>
- MFFields should be encoded as simple arrays (not array of
arrays). Typical multi-value fields such as normals, keyValues
would be trnalsted to TypedArrays of GLBuffers anyway and for
these operations arrays of array is only degrade the performance
and have very little added value<br>
<br>
Just my 2 cents,<br>
Kristian<br>
<br>
<br>
</div>
<blockquote
cite="mid:CAO=4Q_Q1bsfiYqdMBBkvV+RYaju4sPOtv1BNQeBptPx8dHt-2A@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>Hi everyone,</div>
<div><br>
</div>
<div><br>
</div>
<div>> JSON is a built-in JavaScript object. This works out
of the box: the parse method simply creates a valid JS object
from a JSON string.</div>
<div>> The resulting object tree however still has to be
traversed to attach meaning and behavior.</div>
<div><br>
</div>
<div>Exactly: the way the engine chooses to render the
scenegraph is up to it, the JSON data is only meant to
initialize the scenegraph in the 3D engine (and optionally
export its state at a given moment if needed).</div>
<div><br>
</div>
<div><br>
</div>
<div>Which is actually why it would feel redundant to have
prototypes inside JSON if you use it in for Javascript because
in real life I'd use real JS modules if I need a custom object
type with properties and methods (CommonJS, AMD, ES6 modules,
typescript modules, factories or whatever the author prefers)
because:</div>
<div> - it's the same scripting language as the rest of the
application</div>
<div> - it can be optimized with the rest of the application</div>
<div> - it can be tested with the rest of the application</div>
<div> - it can refer to and interact with non-3D modules (e.g. a
thirdparty library for formatting Date timestamps)</div>
<div> - no eval()</div>
<div><br>
</div>
<div><br>
</div>
<div>My goals for a scenegraph format are:</div>
<div> - lightweight to parse</div>
<div> - meaningful and low complexity because it's simpler to
think with, easier to read, easier to diff between two states,
and easier to sync between devices</div>
<div> - easy to require(), to use the same package management as
the rest of the application code and assets</div>
<div><br>
</div>
<div>However I'm fine not having feature parity with XML if it
keeps it lightweight and straightforward, so this is more a
VRML/X3D-inspired format, not "real X3D".</div>
<div><br>
</div>
<div><br>
</div>
<div>Example (the "_type" is omitted in some nodes because I
also have a concept of "Default type" for some fields, e.g.
how most of the time the value in "Shape.appearance.material"
is a Material node):</div>
<div><br>
</div>
<div><span class="" style="white-space:pre"> </span>[</div>
<div><span class="" style="white-space:pre"> </span>{</div>
<div><span class="" style="white-space:pre"> </span>"_type":
"Shape",</div>
<div><span class="" style="white-space:pre"> </span>"appearance":
{</div>
<div><span class="" style="white-space:pre"> </span>"material":
{</div>
<div><span class="" style="white-space:pre"> </span>"transparency":
0.5,</div>
<div><span class="" style="white-space:pre"> </span>"diffuseColor":
[0.8, 1, 0.8]</div>
<div><span class="" style="white-space:pre"> </span>}</div>
<div><span class="" style="white-space:pre"> </span>},</div>
<div><span class="" style="white-space:pre"> </span>"geometry":
{</div>
<div><span class="" style="white-space:pre"> </span>"_type":
'Box',</div>
<div><span class="" style="white-space:pre"> </span>"size": [2,
1, 2]</div>
<div><span class="" style="white-space:pre"> </span>}</div>
<div><span class="" style="white-space:pre"> </span>},</div>
<div><span class="" style="white-space:pre"> </span>{</div>
<div><span class="" style="white-space:pre"> </span>"_type":
"MyCustomObjectType",</div>
<div><span class="" style="white-space:pre"> </span>"translation":
[0, 0, 1],</div>
<div><span class="" style="white-space:pre"> </span>"scale":
[2, 2, 2]</div>
<div><span class="" style="white-space:pre"> </span>}</div>
<div><span class="" style="white-space:pre"> </span>]</div>
<div><br>
</div>
<div>And an example (without messaging or engine-specific code)
of one of many ways to create something similar to Protos:</div>
<div><br>
</div>
<div><span class="" style="white-space:pre"> </span>var
MyCustomObjectType = function(data){</div>
<div><span class="" style="white-space:pre"> </span>'use
strict';</div>
<div><span class="" style="white-space:pre"> </span>var _data =
data || {};</div>
<div><span class="" style="white-space:pre"> </span>var _json =
{</div>
<div><span class="" style="white-space:pre"> </span>_type:
'Transform',</div>
<div><span class="" style="white-space:pre"> </span>translation:
_data.translation || [0, 0, 0],</div>
<div><span class="" style="white-space:pre"> </span>scale:
_data.scale || [1, 1, 1],</div>
<div><span class="" style="white-space:pre"> </span>children: [</div>
<div><span class="" style="white-space:pre"> </span>{</div>
<div><span class="" style="white-space:pre"> </span>_type:
'Shape',</div>
<div><span class="" style="white-space:pre"> </span>appearance:
{</div>
<div><span class="" style="white-space:pre"> </span>material: {</div>
<div><span class="" style="white-space:pre"> </span>transparency:
0.5,</div>
<div><span class="" style="white-space:pre"> </span>diffuseColor:
[0.8, 1, 0.8]</div>
<div><span class="" style="white-space:pre"> </span>}</div>
<div><span class="" style="white-space:pre"> </span>},</div>
<div><span class="" style="white-space:pre"> </span>geometry: {</div>
<div><span class="" style="white-space:pre"> </span>_type:
'Sphere',</div>
<div><span class="" style="white-space:pre"> </span>radius: 5</div>
<div><span class="" style="white-space:pre"> </span>}</div>
<div><span class="" style="white-space:pre"> </span>}</div>
<div><span class="" style="white-space:pre"> </span>]</div>
<div><span class="" style="white-space:pre"> </span>};</div>
<div><span class="" style="white-space:pre"> </span>Object.defineProperty(</div>
<div><span class="" style="white-space:pre"> </span>this,</div>
<div><span class="" style="white-space:pre"> </span>'json',</div>
<div><span class="" style="white-space:pre"> </span>{</div>
<div><span class="" style="white-space:pre"> </span>configurable:
false,</div>
<div><span class="" style="white-space:pre"> </span>enumerable:
true,</div>
<div><span class="" style="white-space:pre"> </span>writable:
false,</div>
<div><span class="" style="white-space:pre"> </span>value:
function(){</div>
<div><span class="" style="white-space:pre"> </span>return
_json;</div>
<div><span class="" style="white-space:pre"> </span>}</div>
<div><span class="" style="white-space:pre"> </span>}</div>
<div><span class="" style="white-space:pre"> </span>);</div>
<div><span class="" style="white-space:pre"> </span>};</div>
<div><br>
</div>
<div><span class="" style="white-space:pre"> </span>MyCustomObjectType.prototype.modifySomething
= function(){</div>
<div><span class="" style="white-space:pre"> </span>'use
strict';</div>
<div><span class="" style="white-space:pre"> </span>//</div>
<div><span class="" style="white-space:pre"> </span>//</div>
<div><span class="" style="white-space:pre"> </span>};</div>
<div><br>
</div>
<div><span class="" style="white-space:pre"> </span>module.exports
= MyCustomObjectType;</div>
<div><br>
</div>
<div><br>
</div>
<div>See you,</div>
<div>Cecile</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
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</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
_______________________________________________________________________________
Kristian Sons
Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI
Agenten und Simulierte Realität
Campus, Geb. D 3 2, Raum 0.77
66123 Saarbrücken, Germany
Phone: +49 681 85775-3833
Phone: +49 681 302-3833
Fax: +49 681 85775–2235
<a class="moz-txt-link-abbreviated" href="mailto:kristian.sons@dfki.de">kristian.sons@dfki.de</a>
<a class="moz-txt-link-freetext" href="http://www.xml3d.org">http://www.xml3d.org</a>
Geschäftsführung: Prof. Dr. Dr. h.c. mult. Wolfgang Wahlster (Vorsitzender)
Dr. Walter Olthoff
Vorsitzender des Aufsichtsrats: Prof. Dr. h.c. Hans A. Aukes
Amtsgericht Kaiserslautern, HRB 2313
_______________________________________________________________________________</pre>
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