1259 lines
67 KiB
XML
1259 lines
67 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
|
||
<!-- name="GENERATOR" content="github.com/mmarkdown/mmark Mmark Markdown Processor - mmark.miek.nl" -->
|
||
<rfc version="3" ipr="trust200902" docName="draft-XRFRAGMENTS-leonvankammen-00" submissionType="IETF" category="info" xml:lang="en" xmlns:xi="http://www.w3.org/2001/XInclude" indexInclude="true" consensus="true">
|
||
|
||
<front>
|
||
<title>XR Fragments</title><seriesInfo value="draft-XRFRAGMENTS-leonvankammen-00" stream="IETF" status="informational" name="XR-Fragments"></seriesInfo>
|
||
<author initials="L.R." surname="van Kammen" fullname="L.R. van Kammen"><organization></organization><address><postal><street></street>
|
||
</postal></address></author><date/>
|
||
<area>Internet</area>
|
||
<workgroup>Jens & Leon Internet Engineering Task Force</workgroup>
|
||
|
||
<abstract>
|
||
<t>Version: 0.5</t>
|
||
<t>An open specification for hyperlinking & deeplinking 3D fileformats.
|
||
This draft is a specification for interactive URI-controllable 3D files, enabling <eref target="https://github.com/coderofsalvation/hypermediatic">hypermediatic</eref> navigation, to enable a spatial web for hypermedia browsers with- or without a network-connection.<br />
|
||
|
||
XR Fragments allows us to better use implicit metadata inside 3D scene(files), by mapping it to proven technologies like <eref target="https://en.wikipedia.org/wiki/URI_fragment">URI Fragments</eref>.<br />
|
||
</t>
|
||
<t>Almost every idea in this document is demonstrated at <eref target="https://xrfragment.org">https://xrfragment.org</eref></t>
|
||
</abstract>
|
||
|
||
</front>
|
||
|
||
<middle>
|
||
|
||
<section anchor="quick-reference"><name>Quick reference</name>
|
||
|
||
<ol spacing="compact">
|
||
<li><eref target="#abstract">Abstract</eref></li>
|
||
<li><eref target="#index">Index</eref></li>
|
||
<li><eref target="#introduction">Introduction</eref></li>
|
||
<li><eref target="#how-does-it-work">How does it work</eref></li>
|
||
<li><eref target="#what-does-it-solve">What does it solve</eref></li>
|
||
<li><eref target="#hfl-hypermediatic-feedback-loop-for-xr-browsers">HFL (Hypermediatic Feedback Loop) for XR Browsers</eref></li>
|
||
<li><t><eref target="#conventions-and-definitions">Conventions and Definitions</eref></t>
|
||
|
||
<ol spacing="compact">
|
||
<li><eref target="#xr-fragment-url-grammar">XR Fragment URL Grammar</eref></li>
|
||
</ol></li>
|
||
<li><eref target="#spatial-referencing-3d">Spatial Referencing 3D</eref></li>
|
||
<li><t><eref target="#level0-files">Level0: Files</eref></t>
|
||
|
||
<ol spacing="compact">
|
||
<li><eref target="#via-href-metadata">via href metadata</eref></li>
|
||
<li><eref target="#via-chained-extension">via chained extension</eref></li>
|
||
<li><eref target="#via-subdocuments-xattr">via subdocuments/xattr</eref></li>
|
||
<li><eref target="#json-sidecar-file">JSON sidecar-file</eref></li>
|
||
</ol></li>
|
||
<li><t><eref target="#level1-uri">Level1: URI</eref></t>
|
||
|
||
<ol spacing="compact">
|
||
<li><eref target="#list-of-uri-fragments">List of URI Fragments</eref></li>
|
||
<li><eref target="#list-of-explicit-metadata">List of explicit metadata</eref></li>
|
||
</ol></li>
|
||
<li><t><eref target="#level2-href-links">Level2: href links</eref></t>
|
||
|
||
<ol spacing="compact">
|
||
<li><eref target="#interaction-behaviour">Interaction behaviour</eref></li>
|
||
<li><eref target="#xr-viewer-implementation">XR Viewer implementation</eref></li>
|
||
</ol></li>
|
||
<li><t><eref target="#level3-media-fragments">Level3: Media Fragments</eref></t>
|
||
|
||
<ol spacing="compact">
|
||
<li><eref target="#animation-s-timeline">Animation(s) timeline</eref></li>
|
||
<li><eref target="#specify-playback-loopmode">Specify playback loopmode</eref></li>
|
||
<li><eref target="#controlling-embedded-content">Controlling embedded content</eref></li>
|
||
</ol></li>
|
||
<li><t><eref target="#level4-prefix-operators">Level4: prefix operators</eref></t>
|
||
|
||
<ol spacing="compact">
|
||
<li><eref target="#object-teleports">Object teleports</eref></li>
|
||
<li><eref target="#object-multipliers">Object multipliers</eref></li>
|
||
<li><eref target="#de-selectors-and">De/selectors (+ and -)</eref></li>
|
||
<li><eref target="#sharing-object-or-file">Sharing object or file (#|)</eref></li>
|
||
<li><eref target="#xrf-uri-scheme">xrf:// URI scheme</eref></li>
|
||
</ol></li>
|
||
<li><eref target="#level5-uri-templates-rfc6570">Level5: URI Templates (RFC6570)</eref></li>
|
||
<li><t><eref target="#top-level-url-processing">Top-level URL processing</eref></t>
|
||
|
||
<ol spacing="compact">
|
||
<li><eref target="#ux">UX</eref></li>
|
||
</ol></li>
|
||
<li><t><eref target="#example-navigating-content-href-portals">Example: Navigating content href portals</eref></t>
|
||
|
||
<ol spacing="compact">
|
||
<li><eref target="#walking-surfaces">Walking surfaces</eref></li>
|
||
</ol></li>
|
||
<li><eref target="#example-virtual-world-rings">Example: Virtual world rings</eref></li>
|
||
<li><eref target="#additional-scene-metadata">Additional scene metadata</eref></li>
|
||
<li><t><eref target="#accessibility-interface">Accessibility interface</eref></t>
|
||
|
||
<ol spacing="compact">
|
||
<li><eref target="#two-button-navigation">Two-button navigation</eref></li>
|
||
<li><eref target="#overlap-with-fileformat-specific-extensions">Overlap with fileformat-specific extensions</eref></li>
|
||
</ol></li>
|
||
<li><eref target="#vendor-prefixes">Vendor Prefixes</eref></li>
|
||
<li><eref target="#security-considerations">Security Considerations</eref></li>
|
||
<li><eref target="#faq">FAQ</eref></li>
|
||
<li><eref target="#authors">Authors</eref></li>
|
||
<li><eref target="#iana-considerations">IANA Considerations</eref></li>
|
||
<li><eref target="#acknowledgments">Acknowledgments</eref></li>
|
||
<li><eref target="#appendix-definitions">Appendix: Definitions</eref></li>
|
||
</ol>
|
||
</section>
|
||
|
||
<section anchor="introduction"><name>Introduction</name>
|
||
<iref item="Introduction"/><t>How can we add more control to existing text and 3D scenes, without introducing new dataformats?<br />
|
||
|
||
Historically, there's many attempts to create the ultimate 3D fileformat.<br />
|
||
|
||
The lowest common denominator is: designers describing/tagging/naming things using <strong>plain text</strong>.<br />
|
||
|
||
XR Fragments exploits the fact that all 3D models already contain such metadata:</t>
|
||
<t><strong>XR Fragments allows deeplinking of 3D objects by mapping objectnames to URI fragments</strong></t>
|
||
</section>
|
||
|
||
<section anchor="how-does-it-work"><name>How does it work</name>
|
||
<iref item="What is XR Fragments"/><t>XR Fragments utilizes URLs:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li>for 3D viewers/browser to manipulate the camera or objects (via URI fragments)</li>
|
||
<li>implicitly: by mapping 3D objectnames (of a 3D scene/file) to URI fragments (3D deeplinking)</li>
|
||
<li>explicitly: by scanning <tt>href</tt> metadata <strong>inside</strong> 3D scene-files to enable interactions</li>
|
||
<li>externally: progressively enhance a 3D (file) into an experience via <eref target="https://en.wikipedia.org/wiki/Sidecar_file">sidecarfiles</eref></li>
|
||
</ol>
|
||
</section>
|
||
|
||
<section anchor="what-does-it-solve"><name>What does it solve</name>
|
||
<t>It solves:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li>addressibility and <eref target="https://github.com/coderofsalvation/hypermediatic">hypermediatic</eref> navigation of 3D scenes/objects: <eref target="https://en.wikipedia.org/wiki/URI_fragment">URI Fragments</eref> using src/href spatial metadata</li>
|
||
<li>Interlinking text & spatial objects by collapsing space into a Word Graph (XRWG) to show <eref target="#visible-links">visible links</eref></li>
|
||
<li>unlocking spatial potential of the (originally 2D) hashtag (which jumps to a chapter) for navigating XR documents</li>
|
||
<li>refraining from introducing scripting-engines for mundane tasks (and preventing its inevitable security-headaches)</li>
|
||
<li>the gap between text an 3d objects: object-names directly map to hashtags (=fragments), which allows 3D to text transcription.</li>
|
||
</ol>
|
||
<blockquote><t>NOTE: The chapters in this document are ordered from highlevel to lowlevel (technical) as much as possible</t>
|
||
</blockquote><t>XR Fragments views XR experiences through the lens of 3D deeplinked URI's, rather than thru code(frameworks) or protocol-specific browsers (webbrowser e.g.).
|
||
To aid adoption, the standard comprises of various (optional) support-levels, which incorporate existing standards like <eref target="https://www.w3.org/TR/media-frags/">W3C Media Fragments</eref> and <eref target="https://www.rfc-editor.org/rfc/rfc6570">URI Templates (RFC6570)</eref> to promote spatial addressibility, sharing, navigation, filtering and databinding objects for (XR) Browsers.<br />
|
||
</t>
|
||
<blockquote><t>XR Fragments is in a sense, a <b>heuristical 3D format</b> or meta-format, which leverages heuristic rules derived from any 3D scene or well-established 3D file formats, to extract meaningful features from scene hierarchies.<br />
|
||
|
||
These heuristics, enable features that are both meaningful and consistent across different scene representations, allowing <b>higher interop</b> between fileformats, 3D editors, viewers and game-engines.</t>
|
||
</blockquote></section>
|
||
|
||
<section anchor="hfl-hypermediatic-feedback-loop-for-xr-browsers"><name>HFL (Hypermediatic Feedback Loop) for XR Browsers</name>
|
||
<t><iref item="HFL (Hypermediatic Feedback Loop"/> for XR Browsers)</t>
|
||
<t><tt>href</tt> metadata traditionally implies <strong>click</strong> AND <strong>navigate</strong>, however XR Fragments adds stateless <strong>click</strong> (<tt>xrf://....</tt>) via the <tt>xrf://</tt> scheme, which does not change the top-level URL-adress (of the browser).
|
||
This allows for many extra interactions via URLs, which otherwise needs a scripting language.
|
||
These are called <strong>hashbus</strong>-only events/</t>
|
||
<blockquote><t>Being able to use the same URI Fragment DSL for navigation (<tt>href: #foo</tt>) as well as interactions (<tt>href: xrf://#foo</tt>) greatly simplifies implementation, increases HFL, and reduces need for scripting languages.</t>
|
||
</blockquote><t>This opens up the following benefits for traditional & future webbrowsers:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li><eref target="https://github.com/coderofsalvation/hypermediatic">hypermediatic</eref> loading/clicking 3D assets (gltf/fbx e.g.) natively (with or without using HTML).</li>
|
||
<li>potentially allowing 3D assets/nodes to publish XR Fragments to themselves/eachother using the <tt>xrf://</tt> hashbus (<tt>xrf://#person=walk</tt> to trigger <tt>walk</tt>-animation for object <tt>person</tt>)</li>
|
||
<li>potentially collapsing the 3D scene to an wordgraph (for essential navigation purposes) controllable thru a hash(tag)bus</li>
|
||
<li>completely bypassing the security-trap of loading external scripts (by loading 3D model-files, not HTML-javascriptable resources)</li>
|
||
</ul>
|
||
<t>XR Fragments itself are <eref target="https://github.com/coderofsalvation/hypermediatic">hypermediatic</eref> and HTML-agnostic, though pseudo-XR Fragment browsers <strong>can</strong> be implemented on top of HTML/Javascript.</t>
|
||
<table>
|
||
<thead>
|
||
<tr>
|
||
<th>principle</th>
|
||
<th>3D URL</th>
|
||
<th>HTML 2D URL</th>
|
||
</tr>
|
||
</thead>
|
||
|
||
<tbody>
|
||
<tr>
|
||
<td>the XRWG</td>
|
||
<td>wordgraph (collapses 3D scene to tags)</td>
|
||
<td>Ctrl-F (find)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>the hashbus</td>
|
||
<td>hashtags alter camera/scene/object-projections</td>
|
||
<td>hashtags alter document positions</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>src metadata</td>
|
||
<td>renders content and offers sourceportation</td>
|
||
<td>renders content</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>href metadata</td>
|
||
<td>teleports to other XR document</td>
|
||
<td>jumps to other HTML document</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>href metadata</td>
|
||
<td>triggers predefined view</td>
|
||
<td>Media fragments</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>href metadata</td>
|
||
<td>triggers camera/scene/object/projections</td>
|
||
<td>n/a</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>href metadata</td>
|
||
<td>draws visible connection(s) for XRWG 'tag'</td>
|
||
<td>n/a</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>href metadata</td>
|
||
<td>filters certain (in)visible objects</td>
|
||
<td>n/a</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>href metadata</td>
|
||
<td>href="xrf://#-foo&bar"</td>
|
||
<td>href="javascript:hideFooAndShowBar()`</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td></td>
|
||
<td>(this does not update topLevel URI)</td>
|
||
<td>(this is non-standard, non-hypermediatic)</td>
|
||
</tr>
|
||
</tbody>
|
||
</table><blockquote><t>An important aspect of HFL is that URI Fragments can be triggered without updating the top-level URI (default href-behaviour) thru their own 'bus' (<tt>xrf://#.....</tt>). This decoupling between navigation and interaction prevents non-standard things like (<tt>href</tt>:<tt>javascript:dosomething()</tt>).</t>
|
||
</blockquote></section>
|
||
|
||
<section anchor="conventions-and-definitions"><name>Conventions and Definitions</name>
|
||
<iref item="Conventions and Definitions"/><t>See appendix below in case certain terms are not clear.</t>
|
||
|
||
<section anchor="xr-fragment-url-grammar"><name>XR Fragment URL Grammar</name>
|
||
<iref item="XR Fragment URL Grammar"/><t>For typical HTTP-like browsers/applications:</t>
|
||
|
||
<artwork><![CDATA[reserved = gen-delims / sub-delims
|
||
gen-delims = "#" / "&"
|
||
sub-delims = "," / "="
|
||
]]>
|
||
</artwork>
|
||
<blockquote><t>Example: <tt>://foo.com/my3d.gltf#room1&prio=-5&t=0,100</tt></t>
|
||
</blockquote><table>
|
||
<thead>
|
||
<tr>
|
||
<th>Demo</th>
|
||
<th>Explanation</th>
|
||
</tr>
|
||
</thead>
|
||
|
||
<tbody>
|
||
<tr>
|
||
<td><tt>room1</tt></td>
|
||
<td>vector/coordinate argument e.g.</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><tt>room1&cam1</tt></td>
|
||
<td>combinators</td>
|
||
</tr>
|
||
</tbody>
|
||
</table><blockquote><t>this is already implemented in all browsers</t>
|
||
</blockquote><t>Pseudo (non-native) browser-implementations (supporting XR Fragments using HTML+JS e.g.) can use the <tt>?</tt> search-operator to address outbound content.<br />
|
||
|
||
In other words, the URL updates to: <tt>https://me.com?https://me.com/other.glb</tt> when navigating to <tt>https://me.com/other.glb</tt> from inside a <tt>https://me.com</tt> WebXR experience e.g.<br />
|
||
|
||
That way, if the link gets shared, the XR Fragments implementation at <tt>https://me.com</tt> can load the latter (and still indicates which XR Fragments entrypoint-experience/client was used).</t>
|
||
</section>
|
||
</section>
|
||
|
||
<section anchor="spatial-referencing-3d"><name>Spatial Referencing 3D</name>
|
||
<iref item="Spatial Referencing 3D"/><t>3D files contain an hierarchy of objects.<br />
|
||
|
||
XR Fragments assumes the following objectname-to-URI-Fragment mapping, in order to deeplink 3D objects:</t>
|
||
|
||
<artwork><![CDATA[
|
||
my.io/scene.fbx
|
||
+─────────────────────────────+
|
||
│ sky │ src: http://my.io/scene.fbx#sky (includes building,mainobject,floor)
|
||
│ +─────────────────────────+ │
|
||
│ │ building │ │ src: http://my.io/scene.fbx#building (includes mainobject,floor)
|
||
│ │ +─────────────────────+ │ │
|
||
│ │ │ mainobject │ │ │ src: http://my.io/scene.fbx#mainobject (includes floor)
|
||
│ │ │ +─────────────────+ │ │ │
|
||
│ │ │ │ floor │ │ │ │ src: http://my.io/scene.fbx#floor (just floor object)
|
||
│ │ │ │ │ │ │ │
|
||
│ │ │ +─────────────────+ │ │ │
|
||
│ │ +─────────────────────+ │ │
|
||
│ +─────────────────────────+ │
|
||
+─────────────────────────────+
|
||
|
||
]]>
|
||
</artwork>
|
||
<blockquote><t>Every 3D fileformat supports named 3D object, and this name allows URLs (fragments) to reference them (and their children objects).</t>
|
||
</blockquote><t>Clever nested design of 3D scenes allow great ways for re-using content, and/or previewing scenes.<br />
|
||
|
||
For example, to render a portal with a preview-version of the scene, create an 3D object with:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li>href: <tt>https://scene.fbx</tt></li>
|
||
</ul>
|
||
<blockquote><t>It also allows <strong>sourceportation</strong>, which basically means the enduser can teleport to the original XR Document of an <tt>src</tt> embedded object, and see a visible connection to the particular embedded object. Basically an embedded link becoming an outbound link by activating it.</t>
|
||
</blockquote></section>
|
||
|
||
<section anchor="level0-files"><name>Level0: Files</name>
|
||
<iref item="Level0: Files"/><iref item="Level0: Files"/><t>Compatible 3D fileformats: <eref target="https://www.khronos.org/gltf/">glTF</eref>, <eref target="https://openusd.org/release/spec_usdz.html">usdz</eref>, <eref target="https://en.wikipedia.org/wiki/Wavefront_.obj_file">obj</eref>, <eref target="https://www.khronos.org/collada">collada</eref>, <eref target="https://github.com/mrdoob/three.js/wiki/JSON-Object-Scene-format-4">THREE.json</eref>, <eref target="https://en.wikipedia.org/wiki/X3D">X3D</eref> e.g.
|
||
<br />
|
||
</t>
|
||
<t>A 3D scene-file can be considered <b>XR Fragment-compatible</b> when it contains metadata:
|
||
1. implicit: there's at least one object with a name (*)
|
||
2. explicit: (optional) object(s) have (level2) href extras.</t>
|
||
<blockquote><t>* = last wins in case of non-unique names</t>
|
||
</blockquote><t>There are <strong>optional</strong> auto-loaded <eref target="">side-car files</eref> to enable hasslefree <eref target="#XR%20Movies">XR Movies</eref>.<br />
|
||
|
||
they can accomodate developers or applications who (for whatever reason) must not modify the 3D scene-file (a <tt>.glb</tt> e.g.).</t>
|
||
|
||
<section anchor="via-href-metadata"><name>via href metadata</name>
|
||
|
||
<artwork><![CDATA[scene.glb <--- 'href' extra [heuristic] detected inside!
|
||
scene.png (preview thumbnail)
|
||
scene.ogg (soundtrack to plays when global 3D animation starts)
|
||
scene.vtt (subtitles for accessibility or screenreaders)
|
||
scene.json (sidecar JSON-file with explicit metadata)
|
||
]]>
|
||
</artwork>
|
||
<t><strong>heuristics</strong>:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li>if at least one <tt>href</tt> custom property/extra is found in a 3D scene</li>
|
||
<li>The viewer should poll for the above mentioned sidecar-file extensions (and present accordingly)</li>
|
||
</ul>
|
||
</section>
|
||
|
||
<section anchor="via-chained-extension"><name>via chained extension</name>
|
||
|
||
<artwork><![CDATA[scene.xrf.glb <--- '.xrf.' sidecar file heuristic detected!
|
||
scene.xrf.png (preview thumbnail)
|
||
scene.xrf.ogg (soundtrack to plays when global 3D animation starts)
|
||
scene.xrf.vtt (subtitles for accessibility or screenreaders)
|
||
scene.xrf.json (sidecar JSON-file with explicit metadata)
|
||
]]>
|
||
</artwork>
|
||
<blockquote><t>A fallback-mechanism to turn 3D files into <eref target="#XR%20Movies">XR Movies</eref> without editing them.</t>
|
||
</blockquote><t><strong>heuristics</strong>:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li>the chained-extension heuristic <tt>.xrf.</tt> should be present in the filename (<tt>scene.xrf.glb</tt> e.g.)</li>
|
||
</ul>
|
||
</section>
|
||
|
||
<section anchor="via-subdocuments-xattr"><name>via subdocuments/xattr</name>
|
||
<t>More secure protocols (Nextgraph e.g.) don't allow for simply polling files.
|
||
In such case, subdocuments or extended attributes should be polled:</t>
|
||
<blockquote><t>NOTE: in the examples below we use the href-heuristic, but also the <tt>.xrf.</tt> chained-extension applies here.</t>
|
||
</blockquote>
|
||
<artwork><![CDATA[myspreadsheet.ods
|
||
└── explainer.glb <--- 'href' extra [heuristic] detected inside!
|
||
├── explainer.ogg (soundtrack to play when global 3D animation starts)
|
||
├── explainer.png (preview thumnbnail)
|
||
├── explainer.json (sidecar JSON-file with explicit metadata)
|
||
└── explainer.vtt (subtitles for accessibility or screenreaders)
|
||
]]>
|
||
</artwork>
|
||
<t>If only extended attributes (xattr) are available, the respective referenced file can be embedded:</t>
|
||
|
||
<artwork><![CDATA[$ setfattr -n explainer.ogg -v "soundtrack.ogg" explainer.glb
|
||
$ setfattr -n explainer.png -v "thumbnail.png" explainer.glb
|
||
$ setfattr -n explainer.vtt -v "subtitles.vtt" explainer.glb
|
||
]]>
|
||
</artwork>
|
||
<blockquote><t>NOTE: Linux's <tt>setfattr/getfattr</tt> is <tt>xattr</tt> on mac, and <tt>Set-Content/Get-content</tt> on Windows. See <eref target="https://www.lesbonscomptes.com/pxattr/index.html">pxattr</eref> for lowlevel access.</t>
|
||
</blockquote></section>
|
||
|
||
<section anchor="json-sidecar-file"><name>JSON sidecar-file</name>
|
||
<t>For developers, sidecar-file can allow for defining <strong>explicit</strong> XR Fragments links (>level1), outside of the 3D file.<br />
|
||
|
||
This can be done via (objectname/metadata) key/value-pairs in a JSON <eref target="https://en.wikipedia.org/wiki/Sidecar_file">sidecar-file</eref>:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li>experience.glb</li>
|
||
<li>experience.json <tt><----</tt></li>
|
||
</ul>
|
||
|
||
<sourcecode type="json"><![CDATA[{
|
||
"aria-description": "description of scene",
|
||
"button": {
|
||
"href": "#roomB",
|
||
"aria-description": "description of room"
|
||
}
|
||
}
|
||
]]>
|
||
</sourcecode>
|
||
<blockquote><t>This will make object <tt>button</tt> clickable, and teleport the user to object <tt>roomB</tt>.</t>
|
||
</blockquote><t>So after loading <tt>experience.glb</tt> the existence of <tt>experience.json</tt> is detected, to apply the explicit metadata.<br />
|
||
|
||
The sidecar will define (or <strong>override</strong> already existing) extras, which can be handy for multi-user platforms (offer 3D scene customization/personalization to users).</t>
|
||
<blockquote><t>In THREE.js-code this would boil down to:</t>
|
||
</blockquote>
|
||
<sourcecode type="javascript"><![CDATA[ scene.userData['aria-description'] = "description of scene"
|
||
scene.getObjectByName("button").userData.href = "#roomB"
|
||
|
||
// now the XR Fragments parser can process the XR Fragments userData 'extras' in the scene
|
||
]]>
|
||
</sourcecode>
|
||
</section>
|
||
</section>
|
||
|
||
<section anchor="level1-uri"><name>Level1: URI</name>
|
||
<iref item="Level1: URI"/><blockquote><t><strong>XR Fragments allows deeplinking of 3D objects by mapping objectnames to URI fragments</strong></t>
|
||
</blockquote><t>XR Fragments tries to seek to connect the world of text (semantical web / RDF), and the world of pixels.<br />
|
||
|
||
Instead of forcing authors to combine 3D/2D objects programmatically (publishing thru a game-editor e.g.), XR Fragments <strong>integrates all</strong> which allows a universal viewing experience.<br />
|
||
</t>
|
||
|
||
<artwork><![CDATA[ +───────────────────────────────────────────────────────────────────────────────────────────────+
|
||
│ │
|
||
│ U R N │
|
||
│ U R L | │
|
||
│ | |-----------------+--------| │
|
||
│ +--------------------------------------------------| │
|
||
│ | │
|
||
│ + https://foo.com/some/foo/scene.glb#someview <-- http URI (=URL and has URN) │
|
||
│ | │
|
||
│ + ipfs://cfe0987ec9r9098ecr/cats.fbx#someview <-- an IPFS URI (=URL and has URN) │
|
||
│ │
|
||
│ ec09f7e9cf8e7f09c8e7f98e79c09ef89e000efece8f7ecfe9fe <-- an interpeer URI │
|
||
│ │
|
||
│ │
|
||
│ |------------------------+-------------------------| │
|
||
│ | │
|
||
│ U R I │
|
||
│ │
|
||
+───────────────────────────────────────────────────────────────────────────────────────────────+
|
||
|
||
]]>
|
||
</artwork>
|
||
<t>Fact: our typical browser URL's are just <strong>a possible implementation</strong> of URI's (for untapped humancentric potential of URI's <eref target="https://interpeer.io">see interpeer.io</eref> or <eref target="https://nextgraph.org">NextGraph</eref> )</t>
|
||
<blockquote><t>XR Fragments does not look at XR (or the web) thru the lens of HTML or URLs.<br />
|
||
But approaches things from a higherlevel local-first 3D hypermedia browser-perspective.</t>
|
||
</blockquote><t>Below you can see how this translates back into good-old URLs:</t>
|
||
|
||
<artwork><![CDATA[ +───────────────────────────────────────────────────────────────────────────────────────────────+
|
||
│ │
|
||
│ the soul of any URL: ://macro /meso ?micro #nano │
|
||
│ │
|
||
│ 2D URL: ://library.com /document ?search #chapter │
|
||
│ xrf:// │
|
||
│ 4D URL: ://park.com /4Dscene.fbx ─> ?other.glb ─> #object ─> hashbus │
|
||
│ │ #filter │ │
|
||
│ │ #tag │ │
|
||
│ │ (hypermediatic) #material │ │
|
||
│ │ ( feedback ) #animation │ │
|
||
│ │ ( loop ) #texture │ │
|
||
│ │ #variable │ │
|
||
│ │ │ │
|
||
│ XRWG <─────────────────────<─────────────+ │
|
||
│ │ │ │
|
||
│ └─ objects ──────────────>─────────────+ │
|
||
│ │
|
||
│ │
|
||
+───────────────────────────────────────────────────────────────────────────────────────────────+
|
||
|
||
]]>
|
||
</artwork>
|
||
<blockquote><t>?-linked and #-linked navigation are JUST one possible way to implement XR Fragments: the essential goal is to allow a Hypermediatic FeedbackLoop (HFL) between external and internal 4D navigation.</t>
|
||
</blockquote>
|
||
<section anchor="list-of-uri-fragments"><name>List of URI Fragments</name>
|
||
<table>
|
||
<thead>
|
||
<tr>
|
||
<th>fragment</th>
|
||
<th>type</th>
|
||
<th>example</th>
|
||
<th>info</th>
|
||
</tr>
|
||
</thead>
|
||
|
||
<tbody>
|
||
<tr>
|
||
<td><tt>#......</tt></td>
|
||
<td>vector3</td>
|
||
<td><tt>#room1</tt> <tt>#room2</tt> <tt>#cam2</tt></td>
|
||
<td>positions/parents camera(rig) (or XR floor) to xyz-coord/object/camera and upvector</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><eref target="https://www.w3.org/TR/media-frags/">Media Fragments</eref></td>
|
||
<td><eref target="#media%20fragments%20and%20datatypes">media fragment</eref></td>
|
||
<td><tt>#t=0,2&loop</tt></td>
|
||
<td>play (and loop) 3D animation from 0 seconds till 2 seconds</td>
|
||
</tr>
|
||
</tbody>
|
||
</table></section>
|
||
|
||
<section anchor="list-of-explicit-metadata"><name>List of *<em>explicit</em> metadata</name>
|
||
<t>These are the possible 'extras' for 3D nodes and sidecar-files</t>
|
||
<table>
|
||
<thead>
|
||
<tr>
|
||
<th>key</th>
|
||
<th>type</th>
|
||
<th>example (JSON)</th>
|
||
<th>function</th>
|
||
<th>existing compatibility</th>
|
||
</tr>
|
||
</thead>
|
||
|
||
<tbody>
|
||
<tr>
|
||
<td><tt>href</tt></td>
|
||
<td>string</td>
|
||
<td><tt>"href": "b.gltf"</tt></td>
|
||
<td>XR teleport</td>
|
||
<td>custom property in 3D fileformats</td>
|
||
</tr>
|
||
</tbody>
|
||
</table></section>
|
||
</section>
|
||
|
||
<section anchor="level2-href-links"><name>Level2: href links</name>
|
||
<iref item="Level2: href links"/><t>Explicit href metadata ('extras') in a 3D object (of a 3D file), hint the viewer that the user ''can interact'' with that object :</t>
|
||
<t>| fragment | type | example value |
|
||
|<tt>href</tt>| string (uri or predefined view) | <tt>#pyramid</tt><br />
|
||
<tt>#lastvisit</tt><br />
|
||
<tt>xrf://#-someobject</tt><br />
|
||
<tt>://somefile.gltf#foo</tt><br />
|
||
|</t>
|
||
|
||
<section anchor="interaction-behaviour"><name>Interaction behaviour</name>
|
||
<t>When clicking an ''href''-value, the user(camera) is teleport to the referenced object.</t>
|
||
<t>The imported/teleported destination can be another object in the same scene-file, or a different file.</t>
|
||
</section>
|
||
|
||
<section anchor="xr-viewer-implementation"><name>XR Viewer implementation</name>
|
||
<t>| <strong>spec</strong> | <strong>action</strong> | <strong>feature</strong> |
|
||
|-|-|-|
|
||
| level0+1 | hover 3D file <eref target="#via-href-metadata">href</eref> | show the preview PNG thumbnail (if any). |
|
||
| level0+1 | launch 3D file <eref target="#via-href-metadata">href</eref> | replace the current scene with a new 3D file (<tt>href: other.glb</tt> e.g.) |
|
||
| level2 | click internal 3D file <eref target="#via-href-metadata">href</eref> (<tt>#roomB</tt> e.g.) | teleport the camera to the origin of object(name <tt>roomB</tt>). See [[teleport camera]].|
|
||
| level2 | click external 3D file <eref target="#via-href-metadata">href</eref> (<tt>foo.glb</tt> e.g.) | replace the current scene with a new 3D file (<tt>href: other.glb</tt> e.g.) |
|
||
| level2 | hover external 3D file <eref target="#via-href-metadata">href</eref> | show the preview PNG thumbnail (if any sidecar, see level0) |
|
||
| level2 | click <eref target="#via-href-metadata">href</eref> | hashbus: execute without changing the toplevel URL location (<tt>href: xrf://#someObjectName</tt> e.g.) |
|
||
| level3 | click <eref target="#via-href-metadata">href</eref> | set the global 3D animation timeline to its Media Fragment value (<tt>#t=2,3</tt> e.g.) |</t>
|
||
<blockquote><t>NOTE: hashbus links (<tt>xrf://#foo&bar</tt>) don't change the toplevel URL, which makes it ideal for interactions (in contrast to typical <tt>#roomC</tt> navigation, which benefit back/forward browser-buttons), see <a href="#hashbus">hashbus</a> for more info.</t>
|
||
</blockquote></section>
|
||
</section>
|
||
|
||
<section anchor="level3-media-fragments"><name>Level3: Media Fragments</name>
|
||
<iref item="Level3: Media Fragments"/><blockquote><t>these allow for XR Movies with a controllable timeline using <tt>href</tt> URI's with Media Fragments</t>
|
||
</blockquote><t>Just like with 2D media-files, W3C mediafragments (<tt>#t=1,2</tt>) can be used to control a timeline via the <eref target="##t">#t</eref> primitive.
|
||
XR Fragments Level3 makes the 3D timeline, as well as URL-referenced files <strong>controllable</strong> via Media Fragments like:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li>level2 hrefs (<tt>href: #t=4</tt> e.g. to control 3D timeline)</li>
|
||
<li><t>level4: <tt>xrf:</tt> URI scheme:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li><tt>href: xrf:foo.wav#t=0</tt> to play a wav</li>
|
||
<li><tt>href: xrf:news.glb?clone#t=0</tt> to instance and play another experience</li>
|
||
</ul></li>
|
||
</ul>
|
||
|
||
<section anchor="animation-s-timeline"><name>Animation(s) timeline</name>
|
||
<t>controls the animation(s) of the scene (or <tt>src</tt> resource which contains a timeline)</t>
|
||
<t>| fragment | type | functionality |
|
||
| <b>#t</b>=start,stop | <eref target="default:`#t=0`">[vector2]</eref> | start,stop (in seconds |</t>
|
||
<t>| Example Value | Explanation |
|
||
| <tt>#t=1</tt> | play (3D) animations from 1 seconds till end (and stop) |
|
||
| <tt>#t=1,100</tt> | play (3D) animations from 1 till 100 seconds (and stop) |</t>
|
||
</section>
|
||
|
||
<section anchor="specify-playback-loopmode"><name>Specify playback loopmode</name>
|
||
<t>This compensates a missing element from Media Fragments to enable/disable temporal looping. .</t>
|
||
<t>| fragment | type | functionality |
|
||
| <b>#loop</b> | string | enables animation/video/audio loop |
|
||
| <b>#-loop</b> | string | disables animation/video/audio loop |</t>
|
||
</section>
|
||
|
||
<section anchor="controlling-embedded-content"><name>Controlling embedded content</name>
|
||
<t>use [[URI Templates]] to control embedded media, for example a simple video-player:</t>
|
||
|
||
<artwork><![CDATA[ foo.usdz
|
||
│
|
||
├── ◻ loopbutton_enable
|
||
│ └ href: #loop <-- enable global loop
|
||
│
|
||
├── ◻ loopbutton_enable
|
||
│ └ href: #-loop <-- disable global loop
|
||
│
|
||
├── ◻ playbutton
|
||
│ └ href: #t=10&loop <-- play global 3D timeline (all anims) (looped)
|
||
│
|
||
└── ◻ playbutton_external
|
||
└ href: https://my.org/animation.glb#!&t=3,10 <-- import & play external anim
|
||
|
||
]]>
|
||
</artwork>
|
||
</section>
|
||
</section>
|
||
|
||
<section anchor="level4-prefix-operators"><name>Level4: prefix operators</name>
|
||
<iref item="Level4: prefix operators"/><t>Prefixing objectnames with the following simple operators allow for <strong>extremely powerful</strong> XR interactions:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li>#!</li>
|
||
<li>#*</li>
|
||
<li>#+ or #-</li>
|
||
<li>#|</li>
|
||
<li>xrf: URI scheme</li>
|
||
</ul>
|
||
<blockquote><t><strong>Examples:</strong> <tt>#+menu</tt> to show a object, <tt>#-menu</tt> to hide a menu, <tt>#!menu</tt> to teleport a menu, <tt>#*block</tt> to clone a grabbable block, <tt>#|object</tt> to share an object</t>
|
||
</blockquote>
|
||
<section anchor="object-teleports"><name>Object teleports (!)</name>
|
||
<t>Prefixing an object with an exclamation-symbol, will teleport a (local or remote) referenced object from/to its original/usercamera location.<br />
|
||
</t>
|
||
<t>[img[objecteleport.png]]</t>
|
||
<t>Usecases:
|
||
* show/hide objects/buttons (menu e.g.) in front of user
|
||
* embed remote (object within) 3D file via remote URL
|
||
* instance an interactive object near the user regardless of location
|
||
* instance HUD or semi-transparent-textured-sphere (LUT) around the user</t>
|
||
<t><div class="border padding" style="border:4px solid #888">
|
||
<span class="big hi1">#!menu</span>
|
||
</div>
|
||
<br />
|
||
</t>
|
||
<t>Clicking the <eref target="#via-href-metadata">href</eref>-value above will:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li><strong>reposition the referenced object</strong> (menu) to the usercamera's-coordinates.</li>
|
||
<li><strong>zoom</strong> in case of (non-empty) mesh-object: rescale to 1 m³, and position 1m in front of the camera</li>
|
||
<li>toggle behaviour: revert values if 1/2 were already applied</li>
|
||
<li><tt>#+</tt> is always implied (objects are always made visible)</li>
|
||
</ol>
|
||
<t>This tiny but powerful symbol allows incredible interactive possibilities, by carefully positioning re-usable objects outside of a scene (below the usercamera's floor e.g.).</t>
|
||
|
||
<ul spacing="compact">
|
||
<li>href: <tt>#whiteroom&!explainer&!exitmenu</tt></li>
|
||
</ul>
|
||
<blockquote><t>This will teleport the user to <tt>whiteroom</tt> and moves object <tt>explainer</tt> and <tt>exitmenu</tt> in front of the user.</t>
|
||
</blockquote>
|
||
<ul spacing="compact">
|
||
<li>href: `<eref target="https://my.org/foo.glb#!">https://my.org/foo.glb#!</eref></li>
|
||
</ul>
|
||
<t>Clicking the <eref target="#via-href-metadata">href</eref>-value above will:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li>import <tt>foo.glb</tt> from <tt>my.org</tt>'s webserver</li>
|
||
<li>show it in front of the user (because <tt>#!</tt> indicates object teleport)</li>
|
||
</ol>
|
||
|
||
<ul spacing="compact">
|
||
<li>href: <tt>https://foo.glb#roomB&!bar</tt></li>
|
||
</ul>
|
||
<t>Clicking the <eref target="#via-href-metadata">href</eref>-value above will:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li>replace the current scene with <tt>foo.glb</tt></li>
|
||
<li>teleport the user to #roomB inside <tt>foo.glb</tt></li>
|
||
<li><strong>instance the referenced object</strong> (bar inside foo.glb) in front of the user.</li>
|
||
<li>it will update the top-Level URL (because <tt>xrf:</tt> was not used)</li>
|
||
<li>hide the <strong>instanced object</strong> when clicked again (toggle visibility)</li>
|
||
</ol>
|
||
<blockquote><t><strong>NOTE</strong>: level2 teleportation links, as well as instancing mitigates the 'broken embedded image'-issue of HTML: <strong>always</strong> attaching the href-values to <strong>a 3D (preview) object</strong> (that way broken links will not break the design).</t>
|
||
</blockquote><t><strong>Example:</strong> clicking a 3D button with title 'menu' and <eref target="#href">href</eref>-value <tt>xrf:menu.glb?instance#t=4,5</tt> would instance a 3D menu (<tt>menu.glb</tt>) in front of the user, and loop its animation between from 4-5 seconds (<tt>t=4,5</tt>)</t>
|
||
<blockquote><t><strong>NOTE</strong>: combining instance-operators allows dynamic construction of 3D scenes (<tt>#london&!welcomeMenu&!fadeBox</tt> e.g.)</t>
|
||
</blockquote></section>
|
||
|
||
<section anchor="object-multipliers"><name>Object multipliers (*)</name>
|
||
<t>The star-prefix will clone a (local or remote) referenced object to the usercamera's location, and make it grabbable.<br />
|
||
|
||
Usecases:
|
||
* object-picker (build stuff with objects)</t>
|
||
<blockquote><t><strong>NOTE</strong>: this is basically the <eref target="#%23%21">#! operator</eref> which infinitely <strong>clones</strong> the referenced object (instead of repositioning the object).</t>
|
||
</blockquote></section>
|
||
|
||
<section anchor="de-selectors-and"><name>De/selectors (+ and -)</name>
|
||
<blockquote><t>How to show/hide/group material- or object- or animations by name?</t>
|
||
</blockquote><t>Clicking href-values below will show/hide the targeted material- or animation or object-name (incl. children):</t>
|
||
|
||
<ul spacing="compact">
|
||
<li><tt>#-welcome</tt></li>
|
||
<li><tt>#+welcome</tt></li>
|
||
<li><tt>#-VR*</tt></li>
|
||
<li><tt>https://foo.glb#bar&-welcome</tt></li>
|
||
</ul>
|
||
<t>Matching logic:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li>- and + prefix for exact matches (welcome e.g.)</li>
|
||
<li>* postfix for match beginning (VR_skybox VR_skyboxmat e.g.)</li>
|
||
</ul>
|
||
<blockquote><t>NOTE: to hide a skybox when importing/loading a 3D file (force AR) is possible by linking to `<tt>https://my.org/foo.glb#-skybox</tt> or <tt>https://my.org/foo.glb#-skyboxmaterial</tt></t>
|
||
</blockquote></section>
|
||
|
||
<section anchor="sharing-object-or-file"><name>Sharing object or file (#|)</name>
|
||
<t>The pipe-symbol (<tt>|</tt>) sends a (targeted) object to the OS.
|
||
Clicking the href-value below will:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li>share the (targeted object in the) file to a another application</li>
|
||
</ol>
|
||
<blockquote><t>This URL can be fed straight into <eref target="https://developer.mozilla.org/en-US/docs/Web/API/Web_Share_API">Web Share API</eref> or <eref target="https://www.freedesktop.org/wiki/Software/xdg-utils/">xdg-open</eref></t>
|
||
</blockquote>
|
||
<ul spacing="compact">
|
||
<li>href: <tt>xrf://#|bar</tt></li>
|
||
</ul>
|
||
<blockquote><t><strong>NOTE</strong>: sharing is limited to (internal objects) via <tt>xrf:</tt> scheme-only</t>
|
||
</blockquote></section>
|
||
|
||
<section anchor="xrf-uri-scheme"><name>xrf:// URI scheme</name>
|
||
<t>Prefixing the <tt>xrf:</tt> to <eref target="#href">href</eref>-values <strong>will prevent</strong> <eref target="#📜%20level2:%20explicit%20links">level2</eref> <eref target="#href">href</eref>-values from changing the top-Level URL.</t>
|
||
<blockquote><t><strong>Usecase</strong>: for non-shareable URLs like <tt>href: xrf:#t=4,5</tt>, to display a stateful msg e.g.).</t>
|
||
</blockquote><t><strong>Reason:</strong> XR Fragments is inspired by HTML's <eref target="https://en.wikipedia.org/wiki/Hyperlink">href-attribute</eref>, which does various things:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li>it updates the browser-location</li>
|
||
<li>it makes something clickable</li>
|
||
<li>it jumps to another document / elsewhere in the same document</li>
|
||
<li>and more</li>
|
||
</ol>
|
||
<t>The <tt>xrf:</tt> scheme will just do 2 & 3 (so the URL-values will not leak into the top-level URL).</t>
|
||
<blockquote><t><strong>compliance with RFC 3986</strong>: unimplemented/unknown URI schemes (<tt>xrf:...</tt> e.g.) will not update the top-level URL</t>
|
||
</blockquote></section>
|
||
</section>
|
||
|
||
<section anchor="level5-uri-templates-rfc6570"><name>Level5: URI Templates (RFC6570)</name>
|
||
<t><iref item="Level5: URI Templates (RFC6570"/>)</t>
|
||
<t>XR Fragments adopts Level1 URI <strong>Fragment</strong> expansion to provide safe interactivity.<br />
|
||
|
||
This is non-normative, and the draft spec is available on request.</t>
|
||
</section>
|
||
|
||
<section anchor="top-level-url-processing"><name>Top-level URL processing</name>
|
||
<iref item="Top-level URL processing"/><blockquote><t>Example URL: <tt>://foo/world.gltf#room1&t=10&cam</tt></t>
|
||
</blockquote><t>The URL-processing-flow for hypermedia browsers goes like this:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li>IF scene operators and/or animation operator (<tt>t</tt>) are present in the URL then (re)position the camera (to <tt>room1</tt>) and/or animation-range (<tt>10</tt>) accordingly.</li>
|
||
<li>IF no camera-position has been set in <b>step 1 or 2</b> assume <tt>0,0,0</tt> as camera coordinate (XR: add user-height) (<eref target="https://github.com/coderofsalvation/xrfragment/blob/main/src/3rd/js/three/navigator.js#L31]]">example</eref>)</li>
|
||
<li>IF a camera-object exists with name <tt>cam</tt> assume that user(camera) position</li>
|
||
</ol>
|
||
|
||
<section anchor="ux"><name>UX</name>
|
||
<t>End-users should always have read/write access to:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li>the current (toplevel) <b>URL</b> (an URLbar etc)</li>
|
||
<li>URL-history (a <b>back/forward</b> button e.g.)</li>
|
||
<li>Clicking/Touching an <tt>href</tt> navigates (and updates the URL) to another scene/file (and coordinate e.g. in case the URL contains XR Fragments).</li>
|
||
</ol>
|
||
</section>
|
||
</section>
|
||
|
||
<section anchor="example-navigating-content-href-portals"><name>Example: Navigating content href portals</name>
|
||
<iref item="Example: Navigating content href portals"/><t>navigation, portals & mutations</t>
|
||
<table>
|
||
<thead>
|
||
<tr>
|
||
<th>fragment</th>
|
||
<th>type</th>
|
||
<th>example value</th>
|
||
</tr>
|
||
</thead>
|
||
|
||
<tbody>
|
||
<tr>
|
||
<td><tt>href</tt></td>
|
||
<td>string (uri or predefined view)</td>
|
||
<td><tt>#room1</tt><br />
|
||
<tt>#room1</tt><br />
|
||
<tt>://somefile.gltf#room1</tt><br />
|
||
</td>
|
||
</tr>
|
||
</tbody>
|
||
</table>
|
||
<ol>
|
||
<li><t>clicking an outbound ''external''- or ''file URI'' fully replaces the current scene and assumes <tt>room2</tt> by default (unless specified)</t>
|
||
</li>
|
||
<li><t>relocation/reorientation should happen locally for local URI's (<tt>#....</tt>)</t>
|
||
</li>
|
||
<li><t>navigation should not happen ''immediately'' when user is more than 5 meter away from the portal/object containing the href (to prevent accidental navigation e.g.)</t>
|
||
</li>
|
||
<li><t>URL navigation should always be reflected in the client URL-bar (in case of javascript: see [<eref target="https://github.com/coderofsalvation/xrfragment/blob/dev/src/3rd/js/three/navigator.js">here</eref> for an example navigator), and only update the URL-bar after the scene (default fragment <tt>#</tt>) has been loaded.</t>
|
||
</li>
|
||
<li><t>In immersive XR mode, the navigator back/forward-buttons should be always visible (using a wearable e.g., see [<eref target="https://github.com/coderofsalvation/xrfragment/blob/dev/example/aframe/sandbox/index.html#L26-L29">here</eref> for an example wearable)</t>
|
||
</li>
|
||
<li><t>make sure that the ''back-button'' of the ''browser-history'' always refers to the previous position (see [<eref target="https://github.com/coderofsalvation/xrfragment/blob/main/src/3rd/js/three/xrf/href.js#L97">here</eref>)</t>
|
||
</li>
|
||
<li><t>ignore previous rule in special cases, like clicking an <tt>href</tt> using camera-portal collision (the back-button could cause a teleport-loop if the previous position is too close)</t>
|
||
</li>
|
||
<li><t>href-events should bubble upward the node-tree (from children to ancestors, so that ancestors can also conain an href), however only 1 href can be executed at the same time.</t>
|
||
</li>
|
||
<li><t>the end-user navigator back/forward buttons should repeat a back/forward action until a <tt>#...</tt> primitive is found (the stateless xrf:// href-values should not be pushed to the url-history)</t>
|
||
</li>
|
||
</ol>
|
||
<t><eref target="https://github.com/coderofsalvation/xrfragment/blob/main/src/3rd/js/three/xrf/href.js">» example implementation</eref><br />
|
||
|
||
<eref target="https://github.com/coderofsalvation/xrfragment/blob/main/example/assets/href.gltf#L192">» example 3D asset</eref><br />
|
||
|
||
<eref target="https://github.com/coderofsalvation/xrfragment/issues/1">» discussion</eref><br />
|
||
</t>
|
||
|
||
<section anchor="walking-surfaces"><name>Walking surfaces</name>
|
||
<blockquote><t>By default position <tt>0,0,0</tt> of the 3D scene represents the walkable plane, however this is overridden when the following applies:</t>
|
||
</blockquote><t>XR Fragment-compatible viewers can infer this data based scanning the scene for:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li>materialless (nameless & textureless) mesh-objects (without <tt>href</tt> and >0 faces)</li>
|
||
</ol>
|
||
<blockquote><t>optionally the viewer can offer thumbstick, mouse or joystick teleport-tools for non-roomscale VR/AR setups.</t>
|
||
</blockquote></section>
|
||
</section>
|
||
|
||
<section anchor="example-virtual-world-rings"><name>Example: Virtual world rings</name>
|
||
<iref item="Example: Virtual world rings"/><t>Consider 3D scenes linking to eachother using these <tt>href</tt> values, attached to 3D button-objects:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li><tt>href: schoolA.edu/projects.gltf#math</tt></li>
|
||
<li><tt>href: schoolB.edu/projects.gltf#math</tt></li>
|
||
<li><tt>href: university.edu/projects.gltf#math</tt></li>
|
||
</ul>
|
||
<t>This would teleport users to the math-projects of those universities.<br />
|
||
|
||
Now consider adding a 'webring index'-button to each file, with this href-value:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li>href: workgroup.edu/webrings.glb#!webringmenu</li>
|
||
</ul>
|
||
<t>This would allow displaying the (remote 3D file) webring menu with various href-buttons inside, all centrally curated by the workgroup.</t>
|
||
</section>
|
||
|
||
<section anchor="additional-scene-metadata"><name>Additional scene metadata</name>
|
||
<iref item="Additional scene metadata"/><t>XR Fragments does not aim to redefine the metadata-space or accessibility-space by introducing its own cataloging-metadata fields.
|
||
Instead, it encourages browsers to scan nodes for the following custom properties:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li><eref target="https://spdx.dev/">SPDX</eref> license information</li>
|
||
<li><eref target="https://www.w3.org/WAI/standards-guidelines/aria/">ARIA</eref> attributes (<tt>aria-*: .....</tt>)</li>
|
||
<li><eref target="https://datapackage.org">datapackage.json</eref> findability, accessibility, interoperability, and reusability of data</li>
|
||
</ul>
|
||
<t>ARIA's <tt>aria-description</tt>-metadata is normative, to aid accessibility and scene transcripts</t>
|
||
<blockquote><t><strong>NOTE</strong>: please always start <tt>aria-description</tt> with a verb to aid transcripts.</t>
|
||
</blockquote><t>The following metadata are non-normative but encouraged, since they are popular and cheap to parse:</t>
|
||
|
||
<ul spacing="compact">
|
||
<li><eref target="https://json-ld.org">RDF/JSON-LD</eref> like <eref target="https://mvmd.org/standards/gltf/">this example</eref> or via glTF's <eref target="https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_xmp_json_ld">KHR_xmp_json_ld extension</eref></li>
|
||
<li><eref target="https://ogp.me">Open Graph</eref> attributes (<tt>og:*: .....</tt>)</li>
|
||
<li><eref target="https://www.dublincore.org/specifications/dublin-core/application-profile-guidelines/">Dublin-Core</eref> attributes(<tt>dc:*: .....</tt>)</li>
|
||
<li><eref target="https://bibtex.eu/fields">BibTex</eref> when known bibtex-keys exist with values enclosed in <tt>{</tt> and <tt>},</tt></li>
|
||
</ul>
|
||
<blockquote><t>Example: object 'tryceratops' with <tt>aria-description: is a huge dinosaurus standing on a #mountain</tt> generates transcript <tt>#tryceratops is a huge dinosaurus standing on a #mountain</tt>, where the hashtags are clickable XR Fragments (activating the visible-links in the XR browser).</t>
|
||
</blockquote><t>Individual nodes can be enriched with such metadata, but most importantly the scene node:</t>
|
||
<table>
|
||
<thead>
|
||
<tr>
|
||
<th>metadata key</th>
|
||
<th>example value</th>
|
||
</tr>
|
||
</thead>
|
||
|
||
<tbody>
|
||
<tr>
|
||
<td><tt>aria-description</tt>, <tt>og:description</tt>, <tt>dc:description</tt></td>
|
||
<td><tt>An immersive experience about Triceratops</tt> (*)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><tt>SPDX</tt></td>
|
||
<td><tt>CC0-1.0</tt></td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><tt>dc:creator</tt></td>
|
||
<td><tt>John Doe</tt></td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><tt>dc:title</tt>, <tt>og:title</tt></td>
|
||
<td>'Triceratops` (*)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><tt>og:site_name</tt></td>
|
||
<td><tt>https://xrfragment.org</tt></td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><tt>dc.publisher</tt></td>
|
||
<td><tt>NLNET</tt></td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><tt>dc.date</tt></td>
|
||
<td><tt>2024-01-01</tt></td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><tt>dc.identifier</tt></td>
|
||
<td><tt>XRFRAGMENT-001</tt></td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><tt>journal</tt> (bibTeX)</td>
|
||
<td><tt>{Future Of Text Vol 3},</tt></td>
|
||
</tr>
|
||
</tbody>
|
||
</table><blockquote><t>* = these are interchangable (only one needs to be defined)</t>
|
||
</blockquote><t>There's no silver bullet when it comes to metadata, so XR Fragment-implementations should support where the metadata is/goes.</t>
|
||
<blockquote><t>These attributes can be scanned and presented during an <tt>href</tt> or <tt>src</tt> eye/mouse-over.</t>
|
||
</blockquote></section>
|
||
|
||
<section anchor="accessibility-interface"><name>Accessibility interface</name>
|
||
<iref item="Accessibility interface"/><t>The addressibility of XR Fragments allows for unique 3D-to-text transcripts, as well as an textual interface to navigate 3D content.<br />
|
||
|
||
Spec:<br />
|
||
<Br></t>
|
||
|
||
<ol spacing="compact">
|
||
<li>The enduser must be able to enable an accessibility-mode (which persists across application/webpage restarts)</li>
|
||
<li>Accessibility-mode must contain a text-input for the user to enter text</li>
|
||
<li>Accessibility-mode must contain a flexible textlog for the user to read (via screenreader, screen, or TTS e.g.)</li>
|
||
<li>the textlog contains <tt>aria-descriptions</tt>, and its narration (Screenreader e.g.) can be skipped (via 2-button navigation)</li>
|
||
<li>The <tt>back</tt> command should navigate back to the previous URL (alias for browser-backbutton)</li>
|
||
<li>The <tt>forward</tt> command should navigate back to the next URL (alias for browser-nextbutton)</li>
|
||
<li>A destination is a 3D node containing an <tt>href</tt> with a <tt>#...</tt> XR fragment (which matches a 3d object name)</li>
|
||
<li>The <tt>go</tt> command should list all possible destinations</li>
|
||
<li>The <tt>go left</tt> command should move the camera around 0.3 meters to the left</li>
|
||
<li>The <tt>go right</tt> command should move the camera around 0.3 meters to the right</li>
|
||
<li>The <tt>go forward</tt> command should move the camera 0.3 meters forward (direction of current rotation).</li>
|
||
<li>The <tt>rotate left</tt> command should rotate the camera 0.3 to the left</li>
|
||
<li>The <tt>rotate left</tt> command should rotate the camera 0.3 to the right</li>
|
||
<li>The (dynamic) <tt>go abc</tt> command should navigate to <tt>#scene2</tt> in case there's a 3D node with name <tt>abc</tt> and <tt>href</tt> value <tt>#scene2</tt></li>
|
||
<li>The <tt>look</tt> command should give an (contextual) 3D-to-text transcript, by scanning the <tt>aria-description</tt> values of the current <tt>#...</tt> (3D object) value (including its children)</li>
|
||
<li>The <tt>do</tt> command should list all possible <tt>href</tt> values which don't contain an <tt>#...</tt> XR Fragment</li>
|
||
<li>The (dynamic) <tt>do abc</tt> command should navigate/execute <tt>https://.../...</tt> in case a 3D node exist with name <tt>abc</tt> and <tt>href</tt> value <tt>https://.../...</tt></li>
|
||
</ol>
|
||
|
||
<section anchor="two-button-navigation"><name>Two-button navigation</name>
|
||
<t>For specific user-profiles, gyroscope/mouse/keyboard/audio/visuals will not be available.<br />
|
||
|
||
Therefore a 2-button navigation-interface is the bare minimum interface:</t>
|
||
|
||
<ol spacing="compact">
|
||
<li>objects with href metadata can be cycled via a key (tab on a keyboard)</li>
|
||
<li>objects with href metadata can be activated via a key (enter on a keyboard)</li>
|
||
<li>the TTS reads the href-value (and/or aria-description if available)</li>
|
||
</ol>
|
||
</section>
|
||
|
||
<section anchor="overlap-with-fileformat-specific-extensions"><name>Overlap with fileformat-specific extensions</name>
|
||
<t>Some 3D scene-fileformats have support for extensions.
|
||
What if the functionality of those overlap?
|
||
For example, GLTF has the <tt>OMI_LINK</tt> extension which might overlap with XR Fragment's <tt>href</tt>:</t>
|
||
<blockquote><t>Priority Order and Precedence, otherwise fallback applies</t>
|
||
</blockquote><t>1.<strong>Extensions Take Precedence</strong>: Since glTF-specific extensions are designed with the format’s
|
||
specific needs and optimizations in mind, they should take precedence over extras metadata
|
||
in cases where both contain overlapping functionality.
|
||
This approach aligns with the idea that extensions are more likely to be interpreted uniformly by glTF-compatible software.</t>
|
||
|
||
<ol spacing="compact" start="2">
|
||
<li><strong>Fallback Fall-through Mechanism</strong>:
|
||
If a glTF implementation does not support a particular extension, the (XRF) extras field can serve as a fallback. This way, metadata provided in extras can still be useful for applications that don't handle certain extensions.</li>
|
||
</ol>
|
||
<blockquote><t><strong>Example 1</strong> In case of the OMI_LINK glTF extension (<tt>href: https://nlnet.nl</tt>) and an XR Fragment (<tt>href: #otherroom</tt> or <tt>href: otherplanet.glb</tt>), it is clear that <tt>https://nlnet.nl</tt> should open in a browsertab, whereas the XR Fragment links should teleport the user. If the OMI_LINK contains an XR Fragment (<tt>#room1</tt> e.g.) a teleport should be performed only (and other [overlapping] metadata should be ignored).</t>
|
||
<t><strong>Example 2</strong> If an Extensions uses XR Fragments in URI's (<tt>href: #otherroom</tt> or <tt>href: xrf://-walls</tt> in OMI_LINK e.g.), then perform them according to XR Fragment spec (teleport user). But only once: ignore further overlapping metadata for that usecase.</t>
|
||
</blockquote></section>
|
||
</section>
|
||
|
||
<section anchor="vendor-prefixes"><name>Vendor Prefixes</name>
|
||
<iref item="Vendor Prefixes"/><t>Vendor-specific metadata in a 3D scenefiles, are similar to vendor-specific <eref target="https://en.wikipedia.org/wiki/CSS#Vendor_prefixes">CSS-prefixes</eref> (<tt>-moz-opacity: 0.2</tt> e.g.).
|
||
This allows popular 3D engines/frameworks, to initialize specific features when loading a scene/object, in a progressive enhanced way.</t>
|
||
<t>Vendor Prefixes allows embedding 3D engines/framework-specific features a 3D file via metadata:</t>
|
||
<table>
|
||
<thead>
|
||
<tr>
|
||
<th>what</th>
|
||
<th>XR metadata</th>
|
||
<th>Lowest common denominator</th>
|
||
</tr>
|
||
</thead>
|
||
|
||
<tbody>
|
||
<tr>
|
||
<td>CSS</td>
|
||
<td>vendor-agnostic</td>
|
||
<td>2D canvas + object referencing/styling</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>XR Fragments</td>
|
||
<td>vendor-agnostic</td>
|
||
<td>3D camera + object(file) load/embed/click/referencing</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>Vendor prefixs</td>
|
||
<td>vendor-<strong>specific</strong></td>
|
||
<td>Specialized Entity-Component implementation</td>
|
||
</tr>
|
||
</tbody>
|
||
</table><blockquote><t>Why? Because not all XR interactions can/should be solved/standardized by embedding XR Fragments into any 3D file.
|
||
The lowest common denominator between 3D engines is the 'entity'-part of their entity-component-system (ECS). The 'component'-part can be progressively enhanced via vendor prefixes.</t>
|
||
</blockquote><t>For example, the following metadata can be added to a .glb file, to make an object grabbable in AFRAME:</t>
|
||
|
||
<artwork><![CDATA[+────────────────────────────────────────────────────────────────────────────────────────────────────────+
|
||
│ http://y.io/z.glb | AFRAME app │
|
||
│-----------------------------------------------+--------------------------------------------------------│
|
||
│ | │
|
||
│ | after loading the glb, john can be placed into the │
|
||
│ +-[3D mesh]-+ | castle via hands, because the author added metadata to │
|
||
│ | / \ | | john via either: │
|
||
│ | / \ | | │
|
||
│ | / \ | | 1. Blender (custom property-box, no plugins needed) │
|
||
│ | |_____| | | │
|
||
│ +-----│-----+ | 2. javascript-code: │
|
||
│ │ | │
|
||
│ ├─ name: castle | for( var com in this.el.components ){ │
|
||
│ └─ tag: house baroque | this.el.object3D.userData[`-AFRAME-${com}`] = '' │
|
||
│ | } │
|
||
│ [3D mesh-+ | // save to z.glb in AFRAME inspector │
|
||
│ | ├─ name: john | │
|
||
│ | O ├─ age: 23 | │
|
||
│ | /|\ ├─ -aframe-grabbable: '' | > inits 'grabbable' component on object john │
|
||
│ | / \ ├─ -aframe-material.color: '#F0A' | > inits 'material' component on object john │
|
||
│ | ├─ -aframe-text.value: '{name}{age}'| > inits 'text' component (*) with value 'john' │
|
||
│ | ├─ -three-material.fog: false | > changes material settings in THREE.js app │
|
||
│ | ├─ -godot-Label3D.text: '{name}{age}'| > inits 'Label3D' component (*) in Godot │
|
||
│ +--------+ | │
|
||
│ | │
|
||
├─ -GODOT-version: '4.3' | > exporters/authors can report targeted version │
|
||
├─ -AFRAME-version: '1.6.0' | and (optionally) hint component-repo│
|
||
├─ -AFRAME-info: 'https://git.benetou.fr/comps' │
|
||
│ | │
|
||
+────────────────────────────────────────────────────────────────────────────────────────────────────────+
|
||
]]>
|
||
</artwork>
|
||
|
||
<ul spacing="compact">
|
||
<li>key/value syntax: -<tt><vendorname></tt>-<tt><component|version></tt>.<tt><key></tt> <tt>[string/boolean/float/int]</tt>-value</li>
|
||
</ul>
|
||
<t>String-templatevalues are evaluated as per <eref target="https://www.rfc-editor.org/rfc/rfc6570">URI Templates (RFC6570)</eref> Level 1.</t>
|
||
<blockquote><t>This 'separating of mechanism from policy' (unix rule) does <strong>somewhat</strong> break portability of an XR experience, but still prevents (E-waste of) handcoded virtual worlds. It allows for (XR experience) metadata to survive in future 3D engines and scene-fileformats.</t>
|
||
</blockquote></section>
|
||
|
||
<section anchor="security-considerations"><name>Security Considerations</name>
|
||
<iref item="Security Considerations"/><t>The only dynamic parts are <eref target="https://www.w3.org/TR/media-frags/">W3C Media Fragments</eref> and <eref target="https://www.rfc-editor.org/rfc/rfc6570">URI Templates (RFC6570)</eref>.<br />
|
||
|
||
The use of URI Templates is limited to pre-defined variables and Level0 fragments-expansion only, which makes it quite safe.<br />
|
||
|
||
n fact, it is much safer than relying on a scripting language (javascript) which can change URN too.</t>
|
||
</section>
|
||
|
||
<section anchor="faq"><name>FAQ</name>
|
||
<iref item="FAQ"/><t><strong>Q:</strong> Why is everything HTTP GET-based, what about POST/PUT/DELETE HATEOS<br />
|
||
|
||
<strong>A:</strong> Because it's out of scope: XR Fragment specifies a read-only way to surf XR documents. These things belong in the application layer (for example, an XR Hypermedia browser can decide to support POST/PUT/DELETE requests for embedded HTML thru <tt>src</tt> values)</t>
|
||
<t><strong>Q:</strong> Why isn't there support for scripting, URI Template Fragments are so limited compared to WASM & javascript
|
||
<strong>A:</strong> This is out of scope as it unhyperifies hypermedia, and this is up to XR hypermedia browser-extensions.<br />
|
||
Historically scripting/Javascript seems to been able to turn webpages from hypermedia documents into its opposite (hyperscripted nonhypermedia documents).<br />
|
||
In order to prevent this backward-movement (hypermedia tends to liberate people from finnicky scripting) XR Fragment uses <eref target="https://www.w3.org/TR/media-frags/">W3C Media Fragments</eref> and <eref target="https://www.rfc-editor.org/rfc/rfc6570">URI Templates (RFC6570)</eref>, to prevent unhyperifying itself by hardcoupling to a particular markup or scripting language. <br />
|
||
|
||
XR Fragments supports filtering objects in a scene only, because in the history of the javascript-powered web, showing/hiding document-entities seems to be one of the most popular basic usecases.<br />
|
||
|
||
Doing advanced scripting & networkrequests under the hood are obviously interesting endavours, but this is something which should not be hardcoupled with XR Fragments or hypermedia.<br />
|
||
This perhaps belongs more to browser extensions.<br />
|
||
|
||
Non-HTML Hypermedia browsers should make browser extensions the right place, to 'extend' experiences, in contrast to code/javascript inside hypermedia documents (this turned out as a hypermedia antipattern).</t>
|
||
</section>
|
||
|
||
<section anchor="authors"><name>authors</name>
|
||
<iref item="authors"/>
|
||
<ul spacing="compact">
|
||
<li>Leon van Kammen (@lvk@mastodon.online)</li>
|
||
<li>Jens Finkhäuser (@jens@social.finkhaeuser.de)</li>
|
||
</ul>
|
||
</section>
|
||
|
||
<section anchor="iana-considerations"><name>IANA Considerations</name>
|
||
<iref item="IANA Considerations"/><t>This document has no IANA actions.</t>
|
||
</section>
|
||
|
||
<section anchor="acknowledgments"><name>Acknowledgments</name>
|
||
<iref item="Acknowledgments"/>
|
||
<ul spacing="compact">
|
||
<li><eref target="https://nlnet.nl">NLNET</eref></li>
|
||
<li><eref target="https://futureoftext.org">Future of Text</eref></li>
|
||
<li><eref target="https://visual-meta.info">visual-meta.info</eref></li>
|
||
<li>Michiel Leenaars</li>
|
||
<li>Gerben van der Broeke</li>
|
||
<li>Mauve</li>
|
||
<li>Jens Finkhäuser</li>
|
||
<li>Marc Belmont</li>
|
||
<li>Tim Gerritsen</li>
|
||
<li>Frode Hegland</li>
|
||
<li>Brandel Zackernuk</li>
|
||
<li>Mark Anderson</li>
|
||
</ul>
|
||
</section>
|
||
|
||
<section anchor="appendix-definitions"><name>Appendix: Definitions</name>
|
||
<iref item="Appendix: Definitions"/><table>
|
||
<thead>
|
||
<tr>
|
||
<th>definition</th>
|
||
<th>explanation</th>
|
||
</tr>
|
||
</thead>
|
||
|
||
<tbody>
|
||
<tr>
|
||
<td>human</td>
|
||
<td>a sentient being who thinks fuzzy, absorbs, and shares thought (by plain text, not markuplanguage)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>scene</td>
|
||
<td>a (local/remote) 3D scene or 3D file (index.gltf e.g.)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>3D object</td>
|
||
<td>an object inside a scene characterized by vertex-, face- and customproperty data.</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>URI</td>
|
||
<td>some resource at something somewhere via someprotocol (<tt>http://me.com/foo.glb#foo</tt> or <tt>e76f8efec8efce98e6f</tt> <eref target="https://interpeer.io">see interpeer.io</eref>)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>URL</td>
|
||
<td>something somewhere via someprotocol (<tt>http://me.com/foo.glb</tt>)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>URN</td>
|
||
<td>something at some domain (<tt>me.com/foo.glb</tt>)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>metadata</td>
|
||
<td>custom properties of text, 3D Scene or Object(nodes), relevant to machines and a human minority (academics/developers)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>XR fragment</td>
|
||
<td>URI Fragment with spatial hints (which match the name of a 3D object-, camera-, animation-object)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>the XRWG</td>
|
||
<td>wordgraph (collapses 3D scene to tags)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>the hashbus</td>
|
||
<td>hashtags map to camera/scene-projections</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>spacetime hashtags</td>
|
||
<td>positions camera, triggers scene-preset/time</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>teleportation</td>
|
||
<td>repositioning the enduser to a different position (or 3D scene/file)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>sourceportation</td>
|
||
<td>teleporting the enduser to the original XR Document of an <tt>src</tt> embedded object.</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>placeholder object</td>
|
||
<td>a 3D object which with src-metadata (which will be replaced by the src-data.)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>src</td>
|
||
<td>(HTML-piggybacked) metadata of a 3D object which instances content</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>href</td>
|
||
<td>(HTML-piggybacked) metadata of a 3D object which links to content</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>filter</td>
|
||
<td>URI Fragment(s) which show/hide object(s) in a scene based on name/tag/property (<tt>#cube&-price=>3</tt>)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>visual-meta</td>
|
||
<td><eref target="https://visual.meta.info">visual-meta</eref> data appended to text/books/papers which is indirectly visible/editable in XR.</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>requestless metadata</td>
|
||
<td>metadata which never spawns new requests (unlike RDF/HTML, which can cause framerate-dropping, hence not used a lot in games)</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>FPS</td>
|
||
<td>frames per second in spatial experiences (games,VR,AR e.g.), should be as high as possible</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>introspective</td>
|
||
<td>inward sensemaking ("I feel this belongs to that")</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>extrospective</td>
|
||
<td>outward sensemaking ("I'm fairly sure John is a person who lives in oklahoma")</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td><tt>◻</tt></td>
|
||
<td>ascii representation of an 3D object/mesh</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>(un)obtrusive</td>
|
||
<td>obtrusive: wrapping human text/thought in XML/HTML/JSON obfuscates human text into a salad of machine-symbols and words</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>flat 3D object</td>
|
||
<td>a 3D object of which all verticies share a plane</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>BibTeX</td>
|
||
<td>simple tagging/citing/referencing standard for plaintext</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>BibTag</td>
|
||
<td>a BibTeX tag</td>
|
||
</tr>
|
||
|
||
<tr>
|
||
<td>(hashtag)bibs</td>
|
||
<td>an easy to speak/type/scan tagging SDL (<eref target="https://github.com/coderofsalvation/hashtagbibs">see here</eref> which expands to BibTex/JSON/XML</td>
|
||
</tr>
|
||
</tbody>
|
||
</table></section>
|
||
|
||
</middle>
|
||
|
||
</rfc>
|