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%%%
Title = "XR Fragments"
area = "Internet"
workgroup = "Jens & Leon Internet Engineering Task Force"
[seriesInfo]
name = "XR-Fragments"
value = "draft-XRFRAGMENTS-leonvankammen-00"
stream = "IETF"
status = "informational"
date = 2023-04-12T00:00:00Z
[[author]]
initials="L.R."
surname="van Kammen"
fullname="L.R. van Kammen"
%%%
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<br>
<h1>XR Fragments</h1>
<br>
<pre>
stream: IETF
area: Internet
status: informational
author: Leon van Kammen
date: 2023-04-12T00:00:00Z
workgroup: Internet Engineering Task Force
value: draft-XRFRAGMENTS-leonvankammen-00
</pre>
}-->
.# Abstract
> Version: 0.5
An open specification for hyperlinking & deeplinking 3D fileformats.
This draft is a specification for interactive URI-controllable 3D files, enabling [hypermediatic](https://github.com/coderofsalvation/hypermediatic) 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 [URI Fragments](https://en.wikipedia.org/wiki/URI_fragment).<br>
> Almost every idea in this document is demonstrated at [https://xrfragment.org](https://xrfragment.org)
{mainmatter}
# Quick reference
1. [Abstract](#abstract)
1. [Index](#index)
1. [Introduction](#introduction)
1. [How does it work](#how-does-it-work)
1. [What does it solve](#what-does-it-solve)
1. [HFL (Hypermediatic Feedback Loop) for XR Browsers](#hfl-hypermediatic-feedback-loop-for-xr-browsers)
1. [Conventions and Definitions](#conventions-and-definitions)
1. [XR Fragment URL Grammar](#xr-fragment-url-grammar)
1. [Spatial Referencing 3D](#spatial-referencing-3d)
1. [Level0: Files](#level0-files)
1. [via href metadata](#via-href-metadata)
1. [via chained extension](#via-chained-extension)
1. [via subdocuments/xattr](#via-subdocuments-xattr)
1. [JSON sidecar-file](#json-sidecar-file)
1. [Level1: URI](#level1-uri)
1. [List of URI Fragments](#list-of-uri-fragments)
1. [List of explicit metadata](#list-of-explicit-metadata)
1. [Level2: href links](#level2-href-links)
1. [Interaction behaviour](#interaction-behaviour)
1. [XR Viewer implementation](#xr-viewer-implementation)
1. [Level3: Media Fragments](#level3-media-fragments)
1. [Animation(s) timeline](#animation-s-timeline)
1. [Specify playback loopmode](#specify-playback-loopmode)
1. [Controlling embedded content](#controlling-embedded-content)
1. [Level4: prefix operators](#level4-prefix-operators)
1. [Object teleports](#object-teleports)
1. [Object multipliers](#object-multipliers)
1. [De/selectors (+ and -)](#de-selectors-and)
1. [Sharing object or file (#|)](#sharing-object-or-file)
1. [xrf:// URI scheme](#xrf-uri-scheme)
1. [Level5: URI Templates (RFC6570)](#level5-uri-templates-rfc6570)
1. [Top-level URL processing](#top-level-url-processing)
1. [UX](#ux)
1. [Example: Navigating content href portals](#example-navigating-content-href-portals)
1. [Walking surfaces](#walking-surfaces)
1. [Example: Virtual world rings](#example-virtual-world-rings)
1. [Additional scene metadata](#additional-scene-metadata)
1. [Accessibility interface](#accessibility-interface)
1. [Two-button navigation](#two-button-navigation)
1. [Overlap with fileformat-specific extensions](#overlap-with-fileformat-specific-extensions)
1. [Vendor Prefixes](#vendor-prefixes)
1. [Security Considerations](#security-considerations)
1. [FAQ](#faq)
1. [Authors](#authors)
1. [IANA Considerations](#iana-considerations)
1. [Acknowledgments](#acknowledgments)
1. [Appendix: Definitions](#appendix-definitions)
# Introduction
(!Introduction)
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 **plain text**.<br>
XR Fragments exploits the fact that all 3D models already contain such metadata:
**XR Fragments allows deeplinking of 3D objects by mapping objectnames to URI fragments**
# How does it work
(!What is XR Fragments )
XR Fragments utilizes URLs:
1. for 3D viewers/browser to manipulate the camera or objects (via URI fragments)
2. implicitly: by mapping 3D objectnames (of a 3D scene/file) to URI fragments (3D deeplinking)
3. explicitly: by scanning `href` metadata **inside** 3D scene-files to enable interactions
4. externally: progressively enhance a 3D (file) into an experience via [sidecarfiles](https://en.wikipedia.org/wiki/Sidecar_file)
# What does it solve
It solves:
1. addressibility and [hypermediatic](https://github.com/coderofsalvation/hypermediatic) navigation of 3D scenes/objects: [URI Fragments](https://en.wikipedia.org/wiki/URI_fragment) using src/href spatial metadata
1. Interlinking text & spatial objects by collapsing space into a Word Graph (XRWG) to show [visible links](#visible-links)
1. unlocking spatial potential of the (originally 2D) hashtag (which jumps to a chapter) for navigating XR documents
1. refraining from introducing scripting-engines for mundane tasks (and preventing its inevitable security-headaches)
1. the gap between text an 3d objects: object-names directly map to hashtags (=fragments), which allows 3D to text transcription.
> NOTE: The chapters in this document are ordered from highlevel to lowlevel (technical) as much as possible
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 [W3C Media Fragments](https://www.w3.org/TR/media-frags/) and [URI Templates (RFC6570)](https://www.rfc-editor.org/rfc/rfc6570) to promote spatial addressibility, sharing, navigation, filtering and databinding objects for (XR) Browsers.<br>
> 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.
# HFL (Hypermediatic Feedback Loop) for XR Browsers
(!HFL (Hypermediatic Feedback Loop) for XR Browsers)
`href` metadata traditionally implies **click** AND **navigate**, however XR Fragments adds stateless **click** (`xrf://....`) via the `xrf://` 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 **hashbus**-only events/
> Being able to use the same URI Fragment DSL for navigation (`href: #foo`) as well as interactions (`href: xrf://#foo`) greatly simplifies implementation, increases HFL, and reduces need for scripting languages.
This opens up the following benefits for traditional & future webbrowsers:
* [hypermediatic](https://github.com/coderofsalvation/hypermediatic) loading/clicking 3D assets (gltf/fbx e.g.) natively (with or without using HTML).
* potentially allowing 3D assets/nodes to publish XR Fragments to themselves/eachother using the `xrf://` hashbus (`xrf://#person=walk` to trigger `walk`-animation for object `person`)
* potentially collapsing the 3D scene to an wordgraph (for essential navigation purposes) controllable thru a hash(tag)bus
* completely bypassing the security-trap of loading external scripts (by loading 3D model-files, not HTML-javascriptable resources)
XR Fragments itself are [hypermediatic](https://github.com/coderofsalvation/hypermediatic) and HTML-agnostic, though pseudo-XR Fragment browsers **can** be implemented on top of HTML/Javascript.
| principle | 3D URL | HTML 2D URL |
|-----------------------------|-------------------------------------------------|---------------------------------------|
| the XRWG | wordgraph (collapses 3D scene to tags) | Ctrl-F (find) |
| the hashbus | hashtags alter camera/scene/object-projections | hashtags alter document positions |
| src metadata | renders content and offers sourceportation | renders content |
| href metadata | teleports to other XR document | jumps to other HTML document |
| href metadata | triggers predefined view | Media fragments |
| href metadata | triggers camera/scene/object/projections | n/a |
| href metadata | draws visible connection(s) for XRWG 'tag' | n/a |
| href metadata | filters certain (in)visible objects | n/a |
| href metadata | href="xrf://#-foo&bar" | href="javascript:hideFooAndShowBar()` |
| | (this does not update topLevel URI) | (this is non-standard, non-hypermediatic) |
> 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' (`xrf://#.....`). This decoupling between navigation and interaction prevents non-standard things like (`href`:`javascript:dosomething()`).
# Conventions and Definitions
(!Conventions and Definitions)
See appendix below in case certain terms are not clear.
## XR Fragment URL Grammar
(! XR Fragment URL Grammar )
For typical HTTP-like browsers/applications:
```
reserved = gen-delims / sub-delims
gen-delims = "#" / "&"
sub-delims = "," / "="
```
> Example: `://foo.com/my3d.gltf#room1&prio=-5&t=0,100`
| Demo | Explanation |
|-------------------------------|---------------------------------|
| `room1` | vector/coordinate argument e.g. |
| `room1&cam1` | combinators |
> this is already implemented in all browsers
Pseudo (non-native) browser-implementations (supporting XR Fragments using HTML+JS e.g.) can use the `?` search-operator to address outbound content.<br>
In other words, the URL updates to: `https://me.com?https://me.com/other.glb` when navigating to `https://me.com/other.glb` from inside a `https://me.com` WebXR experience e.g.<br>
That way, if the link gets shared, the XR Fragments implementation at `https://me.com` can load the latter (and still indicates which XR Fragments entrypoint-experience/client was used).
# Spatial Referencing 3D
(!Spatial Referencing 3D )
3D files contain an hierarchy of objects.<br>
XR Fragments assumes the following objectname-to-URI-Fragment mapping, in order to deeplink 3D objects:
```
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)
│ │ │ │ │ │ │ │
│ │ │ +─────────────────+ │ │ │
│ │ +─────────────────────+ │ │
│ +─────────────────────────+ │
+─────────────────────────────+
```
> Every 3D fileformat supports named 3D object, and this name allows URLs (fragments) to reference them (and their children objects).
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:
* href: `https://scene.fbx`
> It also allows **sourceportation**, which basically means the enduser can teleport to the original XR Document of an `src` embedded object, and see a visible connection to the particular embedded object. Basically an embedded link becoming an outbound link by activating it.
# Level0: Files
(!Level0: Files )
(!Level0: Files)
Compatible 3D fileformats: [glTF](https://www.khronos.org/gltf/), [usdz](https://openusd.org/release/spec_usdz.html), [obj](https://en.wikipedia.org/wiki/Wavefront_.obj_file), [collada](https://www.khronos.org/collada), [THREE.json](https://github.com/mrdoob/three.js/wiki/JSON-Object-Scene-format-4), [X3D](https://en.wikipedia.org/wiki/X3D) e.g.
<br>
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.
> \* = last wins in case of non-unique names
There are **optional** auto-loaded [side-car files]() to enable hasslefree [XR Movies](#XR%20Movies).<br>
they can accomodate developers or applications who (for whatever reason) must not modify the 3D scene-file (a `.glb` e.g.).
## via href metadata
```
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)
```
**heuristics**:
* if at least one `href` custom property/extra is found in a 3D scene
* The viewer should poll for the above mentioned sidecar-file extensions (and present accordingly)
## via chained extension
```
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)
```
> A fallback-mechanism to turn 3D files into [XR Movies](#XR%20Movies) without editing them.
**heuristics**:
* the chained-extension heuristic `.xrf.` should be present in the filename (`scene.xrf.glb` e.g.)
## via subdocuments/xattr
More secure protocols (Nextgraph e.g.) don't allow for simply polling files.
In such case, subdocuments or extended attributes should be polled:
> NOTE: in the examples below we use the href-heuristic, but also the `.xrf.` chained-extension applies here.
```
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)
```
If only extended attributes (xattr) are available, the respective referenced file can be embedded:
```
$ 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
```
> NOTE: Linux's `setfattr/getfattr` is `xattr` on mac, and `Set-Content/Get-content` on Windows. See [pxattr](https://www.lesbonscomptes.com/pxattr/index.html) for lowlevel access.
## JSON sidecar-file
For developers, sidecar-file can allow for defining **explicit** XR Fragments links (>level1), outside of the 3D file.<br>
This can be done via (objectname/metadata) key/value-pairs in a JSON [sidecar-file](https://en.wikipedia.org/wiki/Sidecar_file):
* experience.glb
* experience.json `<----`
```json
{
"aria-description": "description of scene",
"button": {
"href": "#roomB",
"aria-description": "description of room"
}
}
```
> This will make object `button` clickable, and teleport the user to object `roomB`.
So after loading `experience.glb` the existence of `experience.json` is detected, to apply the explicit metadata.<br>
The sidecar will define (or **override** already existing) extras, which can be handy for multi-user platforms (offer 3D scene customization/personalization to users).
> In THREE.js-code this would boil down to:
```javascript
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
```
# Level1: URI
(!Level1: URI)
> **XR Fragments allows deeplinking of 3D objects by mapping objectnames to URI fragments**
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 **integrates all** which allows a universal viewing experience.<br>
```
+───────────────────────────────────────────────────────────────────────────────────────────────+
│ │
│ 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 │
│ │
+───────────────────────────────────────────────────────────────────────────────────────────────+
```
Fact: our typical browser URL's are just **a possible implementation** of URI's (for untapped humancentric potential of URI's [see interpeer.io](https://interpeer.io) or [NextGraph](https://nextgraph.org) )
> 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.
Below you can see how this translates back into good-old URLs:
```
+───────────────────────────────────────────────────────────────────────────────────────────────+
│ │
│ 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 ──────────────>─────────────+ │
│ │
│ │
+───────────────────────────────────────────────────────────────────────────────────────────────+
```
> ?-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.
## List of URI Fragments
| fragment | type | example | info |
|-------------------|------------|--------------------|----------------------------------------------------------------------|
| `#......` | vector3 | `#room1` `#room2` `#cam2` | positions/parents camera(rig) (or XR floor) to xyz-coord/object/camera and upvector |
| [Media Fragments](https://www.w3.org/TR/media-frags/) | [media fragment](#media%20fragments%20and%20datatypes) | `#t=0,2&loop` | play (and loop) 3D animation from 0 seconds till 2 seconds|
## List of **explicit* metadata
These are the possible 'extras' for 3D nodes and sidecar-files
| key | type | example (JSON) | function | existing compatibility |
|--------------|----------|------------------------|---------------------|----------------------------------------|
| `href` | string | `"href": "b.gltf"` | XR teleport | custom property in 3D fileformats |
# Level2: href links
(!Level2: href links)
Explicit href metadata ('extras') in a 3D object (of a 3D file), hint the viewer that the user ''can interact'' with that object :
| fragment | type | example value |
|`href`| string (uri or predefined view) | `#pyramid`<br>`#lastvisit`<br>`xrf://#-someobject`<br>`://somefile.gltf#foo`<br> |
## Interaction behaviour
When clicking an ''href''-value, the user(camera) is teleport to the referenced object.
The imported/teleported destination can be another object in the same scene-file, or a different file.
## XR Viewer implementation
| **spec** | **action** | **feature** |
|-|-|-|
| level0+1 | hover 3D file [href](#via-href-metadata) | show the preview PNG thumbnail (if any). |
| level0+1 | launch 3D file [href](#via-href-metadata) | replace the current scene with a new 3D file (`href: other.glb` e.g.) |
| level2 | click internal 3D file [href](#via-href-metadata) (`#roomB` e.g.) | teleport the camera to the origin of object(name `roomB`). See [[teleport camera]].|
| level2 | click external 3D file [href](#via-href-metadata) (`foo.glb` e.g.) | replace the current scene with a new 3D file (`href: other.glb` e.g.) |
| level2 | hover external 3D file [href](#via-href-metadata) | show the preview PNG thumbnail (if any sidecar, see level0) |
| level2 | click [href](#via-href-metadata) | hashbus: execute without changing the toplevel URL location (`href: xrf://#someObjectName` e.g.) |
| level3 | click [href](#via-href-metadata) | set the global 3D animation timeline to its Media Fragment value (`#t=2,3` e.g.) |
> NOTE: hashbus links (`xrf://#foo&bar`) don't change the toplevel URL, which makes it ideal for interactions (in contrast to typical `#roomC` navigation, which benefit back/forward browser-buttons), see <a href="#hashbus">hashbus</a> for more info.
# Level3: Media Fragments
(!Level3: Media Fragments )
> these allow for XR Movies with a controllable timeline using `href` URI's with Media Fragments
Just like with 2D media-files, W3C mediafragments (`#t=1,2`) can be used to control a timeline via the [#t](##t) primitive.
XR Fragments Level3 makes the 3D timeline, as well as URL-referenced files **controllable** via Media Fragments like:
* level2 hrefs (`href: #t=4` e.g. to control 3D timeline)
* level4: `xrf:` URI scheme:
* `href: xrf:foo.wav#t=0` to play a wav
* `href: xrf:news.glb?clone#t=0` to instance and play another experience
## Animation(s) timeline
controls the animation(s) of the scene (or `src` resource which contains a timeline)
| fragment | type | functionality |
| <b>#t</b>=start,stop | [[vector2]] (default:`#t=0`) | start,stop (in seconds |
| Example Value | Explanation |
| `#t=1` | play (3D) animations from 1 seconds till end (and stop) |
| `#t=1,100` | play (3D) animations from 1 till 100 seconds (and stop) |
## Specify playback loopmode
This compensates a missing element from Media Fragments to enable/disable temporal looping. .
| fragment | type | functionality |
| <b>#loop</b> | string | enables animation/video/audio loop |
| <b>#-loop</b> | string | disables animation/video/audio loop |
## Controlling embedded content
use [[URI Templates]] to control embedded media, for example a simple video-player:
```
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
```
# Level4: prefix operators
(!Level4: prefix operators)
Prefixing objectnames with the following simple operators allow for **extremely powerful** XR interactions:
* #!
* #*
* #+ or #-
* #|
* xrf: URI scheme
> **Examples:** `#+menu` to show a object, `#-menu` to hide a menu, `#!menu` to teleport a menu, `#*block` to clone a grabbable block, `#|object` to share an object
## Object teleports (!)
Prefixing an object with an exclamation-symbol, will teleport a (local or remote) referenced object from/to its original/usercamera location.<br>
[img[objecteleport.png]]
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
<div class="border padding" style="border:4px solid #888">
<span class="big hi1">#!menu</span>
</div>
<br>
Clicking the [href](#via-href-metadata)-value above will:
1. **reposition the referenced object** (menu) to the usercamera's-coordinates.
2. **zoom** in case of (non-empty) mesh-object: rescale to 1 m³, and position 1m in front of the camera
3. toggle behaviour: revert values if 1/2 were already applied
4. `#+` is always implied (objects are always made visible)
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.).
* href: `#whiteroom&!explainer&!exitmenu`
> This will teleport the user to `whiteroom` and moves object `explainer` and `exitmenu` in front of the user.
* href: `https://my.org/foo.glb#!
Clicking the [href](#via-href-metadata)-value above will:
1. import `foo.glb` from `my.org`'s webserver
2. show it in front of the user (because `#!` indicates object teleport)
* href: `https://foo.glb#roomB&!bar`
Clicking the [href](#via-href-metadata)-value above will:
1. replace the current scene with `foo.glb`
2. teleport the user to #roomB inside `foo.glb`
3. **instance the referenced object** (bar inside foo.glb) in front of the user.
4. it will update the top-Level URL (because `xrf:` was not used)
5. hide the **instanced object** when clicked again (toggle visibility)
> **NOTE**: level2 teleportation links, as well as instancing mitigates the 'broken embedded image'-issue of HTML: **always** attaching the href-values to **a 3D (preview) object** (that way broken links will not break the design).
**Example:** clicking a 3D button with title 'menu' and [href](#href)-value `xrf:menu.glb?instance#t=4,5` would instance a 3D menu (`menu.glb`) in front of the user, and loop its animation between from 4-5 seconds (`t=4,5`)
> **NOTE**: combining instance-operators allows dynamic construction of 3D scenes (`#london&!welcomeMenu&!fadeBox` e.g.)
## Object multipliers (*)
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)
> **NOTE**: this is basically the [#! operator](#%23%21) which infinitely **clones** the referenced object (instead of repositioning the object).
## De/selectors (+ and -)
* href: `#-welcome` (or `#+welcome`)
Clicking href-value above will do:
1. show/hide the target object (and children)
* href: `#https://my.org/foo.glb/#bar&-welcome`
> **NOTE:** the latter shows that (de)selectors can also be with regular [href](#href)-values
## Sharing object or file (#|)
The pipe-symbol (`|`) sends a (targeted) object to the OS.
Clicking the href-value below will:
1. share the (targeted object in the) file to a another application
> This URL can be fed straight into [Web Share API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Share_API) or [xdg-open](https://www.freedesktop.org/wiki/Software/xdg-utils/)
* href: `xrf://#|bar`
> **NOTE**: sharing is limited to (internal objects) via `xrf:` scheme-only
## xrf:// URI scheme
Prefixing the `xrf:` to [href](#href)-values **will prevent** [level2](#📜%20level2:%20explicit%20links) [href](#href)-values from changing the top-Level URL.
> **Usecase**: for non-shareable URLs like `href: xrf:#t=4,5`, to display a stateful msg e.g.).
**Reason:** XR Fragments is inspired by HTML's [href-attribute](https://en.wikipedia.org/wiki/Hyperlink), which does various things:
1. it updates the browser-location
2. it makes something clickable
3. it jumps to another document / elsewhere in the same document
4. and more
The `xrf:` scheme will just do 2 & 3 (so the URL-values will not leak into the top-level URL).
> **compliance with RFC 3986**: unimplemented/unknown URI schemes (`xrf:...` e.g.) will not update the top-level URL
# Level5: URI Templates (RFC6570)
(!Level5: URI Templates (RFC6570))
XR Fragments adopts Level1 URI **Fragment** expansion to provide safe interactivity.<br>
This is non-normative, and the draft spec is available on request.
# Top-level URL processing
(!Top-level URL processing)
> Example URL: `://foo/world.gltf#room1&t=10&cam`
The URL-processing-flow for hypermedia browsers goes like this:
1. IF scene operators and/or animation operator (`t`) are present in the URL then (re)position the camera (to `room1`) and/or animation-range (`10`) accordingly.
2. IF no camera-position has been set in <b>step 1 or 2</b> assume `0,0,0` as camera coordinate (XR: add user-height) ([example](https://github.com/coderofsalvation/xrfragment/blob/main/src/3rd/js/three/navigator.js#L31]]))
3. IF a camera-object exists with name `cam` assume that user(camera) position
## UX
End-users should always have read/write access to:
1. the current (toplevel) <b>URL</b> (an URLbar etc)
2. URL-history (a <b>back/forward</b> button e.g.)
3. Clicking/Touching an `href` navigates (and updates the URL) to another scene/file (and coordinate e.g. in case the URL contains XR Fragments).
# Example: Navigating content href portals
(!Example: Navigating content href portals)
navigation, portals & mutations
| fragment | type | example value |
|----------|---------------------------------|---------------------------------------------------------------------------------------------------------------------------|
|`href` | string (uri or predefined view) | `#room1`<br>`#room1`<br>`://somefile.gltf#room1`<br> |
1. clicking an outbound ''external''- or ''file URI'' fully replaces the current scene and assumes `room2` by default (unless specified)
2. relocation/reorientation should happen locally for local URI's (`#....`)
3. 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.)
4. URL navigation should always be reflected in the client URL-bar (in case of javascript: see [[here](https://github.com/coderofsalvation/xrfragment/blob/dev/src/3rd/js/three/navigator.js) for an example navigator), and only update the URL-bar after the scene (default fragment `#`) has been loaded.
5. In immersive XR mode, the navigator back/forward-buttons should be always visible (using a wearable e.g., see [[here](https://github.com/coderofsalvation/xrfragment/blob/dev/example/aframe/sandbox/index.html#L26-L29) for an example wearable)
6. make sure that the ''back-button'' of the ''browser-history'' always refers to the previous position (see [[here](https://github.com/coderofsalvation/xrfragment/blob/main/src/3rd/js/three/xrf/href.js#L97))
7. ignore previous rule in special cases, like clicking an `href` using camera-portal collision (the back-button could cause a teleport-loop if the previous position is too close)
8. 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.
9. the end-user navigator back/forward buttons should repeat a back/forward action until a `#...` primitive is found (the stateless xrf:// href-values should not be pushed to the url-history)
[» example implementation](https://github.com/coderofsalvation/xrfragment/blob/main/src/3rd/js/three/xrf/href.js)<br>
[» example 3D asset](https://github.com/coderofsalvation/xrfragment/blob/main/example/assets/href.gltf#L192)<br>
[» discussion](https://github.com/coderofsalvation/xrfragment/issues/1)<br>
## Walking surfaces
> By default position `0,0,0` of the 3D scene represents the walkable plane, however this is overridden when the following applies:
XR Fragment-compatible viewers can infer this data based scanning the scene for:
1. materialless (nameless & textureless) mesh-objects (without `href` and >0 faces)
> optionally the viewer can offer thumbstick, mouse or joystick teleport-tools for non-roomscale VR/AR setups.
# Example: Virtual world rings
(!Example: Virtual world rings )
Consider 3D scenes linking to eachother using these `href` values, attached to 3D button-objects:
* `href: schoolA.edu/projects.gltf#math`
* `href: schoolB.edu/projects.gltf#math`
* `href: university.edu/projects.gltf#math`
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:
* href: workgroup.edu/webrings.glb#!webringmenu
This would allow displaying the (remote 3D file) webring menu with various href-buttons inside, all centrally curated by the workgroup.
# Additional scene metadata
(!Additional scene metadata )
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:
* [SPDX](https://spdx.dev/) license information
* [ARIA](https://www.w3.org/WAI/standards-guidelines/aria/) attributes (`aria-*: .....`)
* [datapackage.json](https://datapackage.org) findability, accessibility, interoperability, and reusability of data
ARIA's `aria-description`-metadata is normative, to aid accessibility and scene transcripts
> **NOTE**: please always start `aria-description` with a verb to aid transcripts.
The following metadata are non-normative but encouraged, since they are popular and cheap to parse:
* [RDF/JSON-LD](https://json-ld.org) like [this example](https://mvmd.org/standards/gltf/) or via glTF's [KHR_xmp_json_ld extension](https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_xmp_json_ld)
* [Open Graph](https://ogp.me) attributes (`og:*: .....`)
* [Dublin-Core](https://www.dublincore.org/specifications/dublin-core/application-profile-guidelines/) attributes(`dc:*: .....`)
* [BibTex](https://bibtex.eu/fields) when known bibtex-keys exist with values enclosed in `{` and `},`
> Example: object 'tryceratops' with `aria-description: is a huge dinosaurus standing on a #mountain` generates transcript `#tryceratops is a huge dinosaurus standing on a #mountain`, where the hashtags are clickable XR Fragments (activating the visible-links in the XR browser).
Individual nodes can be enriched with such metadata, but most importantly the scene node:
| metadata key | example value |
|--------------------------------------------------------|-------------------------------------------------|
| `aria-description`, `og:description`, `dc:description` | `An immersive experience about Triceratops` (*) |
| `SPDX` | `CC0-1.0` |
| `dc:creator` | `John Doe` |
| `dc:title`, `og:title` | 'Triceratops` (*) |
| `og:site_name` | `https://xrfragment.org` |
| `dc.publisher` | `NLNET` |
| `dc.date` | `2024-01-01` |
| `dc.identifier` | `XRFRAGMENT-001` |
| `journal` (bibTeX) | `{Future Of Text Vol 3},` |
> \* = these are interchangable (only one needs to be defined)
There's no silver bullet when it comes to metadata, so XR Fragment-implementations should support where the metadata is/goes.
> These attributes can be scanned and presented during an `href` or `src` eye/mouse-over.
# Accessibility interface
(!Accessibility interface)
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>
1. The enduser must be able to enable an accessibility-mode (which persists across application/webpage restarts)
2. Accessibility-mode must contain a text-input for the user to enter text
3. Accessibility-mode must contain a flexible textlog for the user to read (via screenreader, screen, or TTS e.g.)
4. the textlog contains `aria-descriptions`, and its narration (Screenreader e.g.) can be skipped (via 2-button navigation)
5. The `back` command should navigate back to the previous URL (alias for browser-backbutton)
6. The `forward` command should navigate back to the next URL (alias for browser-nextbutton)
7. A destination is a 3D node containing an `href` with a `#...` XR fragment (which matches a 3d object name)
8. The `go` command should list all possible destinations
9. The `go left` command should move the camera around 0.3 meters to the left
10. The `go right` command should move the camera around 0.3 meters to the right
11. The `go forward` command should move the camera 0.3 meters forward (direction of current rotation).
12. The `rotate left` command should rotate the camera 0.3 to the left
13. The `rotate left` command should rotate the camera 0.3 to the right
14. The (dynamic) `go abc` command should navigate to `#scene2` in case there's a 3D node with name `abc` and `href` value `#scene2`
15. The `look` command should give an (contextual) 3D-to-text transcript, by scanning the `aria-description` values of the current `#...` (3D object) value (including its children)
16. The `do` command should list all possible `href` values which don't contain an `#...` XR Fragment
17. The (dynamic) `do abc` command should navigate/execute `https://.../...` in case a 3D node exist with name `abc` and `href` value `https://.../...`
## Two-button navigation
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:
1. objects with href metadata can be cycled via a key (tab on a keyboard)
2. objects with href metadata can be activated via a key (enter on a keyboard)
3. the TTS reads the href-value (and/or aria-description if available)
## Overlap with fileformat-specific extensions
Some 3D scene-fileformats have support for extensions.
What if the functionality of those overlap?
For example, GLTF has the `OMI_LINK` extension which might overlap with XR Fragment's `href`:
> Priority Order and Precedence, otherwise fallback applies
1.**Extensions Take Precedence**: Since glTF-specific extensions are designed with the formats
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.
2. **Fallback Fall-through Mechanism**:
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.
> **Example 1** In case of the OMI_LINK glTF extension (`href: https://nlnet.nl`) and an XR Fragment (`href: #otherroom` or `href: otherplanet.glb`), it is clear that `https://nlnet.nl` should open in a browsertab, whereas the XR Fragment links should teleport the user. If the OMI_LINK contains an XR Fragment (`#room1` e.g.) a teleport should be performed only (and other [overlapping] metadata should be ignored).
> **Example 2** If an Extensions uses XR Fragments in URI's (`href: #otherroom` or `href: xrf://-walls` 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.
# Vendor Prefixes
(!Vendor Prefixes )
Vendor-specific metadata in a 3D scenefiles, are similar to vendor-specific [CSS-prefixes](https://en.wikipedia.org/wiki/CSS#Vendor_prefixes) (`-moz-opacity: 0.2` e.g.).
This allows popular 3D engines/frameworks, to initialize specific features when loading a scene/object, in a progressive enhanced way.
Vendor Prefixes allows embedding 3D engines/framework-specific features a 3D file via metadata:
| what | XR metadata | Lowest common denominator |
|------------------|---------------------|-------------------------------------------------------|
| CSS | vendor-agnostic | 2D canvas + object referencing/styling |
| XR Fragments | vendor-agnostic | 3D camera + object(file) load/embed/click/referencing |
| Vendor prefixs | vendor-**specific** | Specialized Entity-Component implementation |
> 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.
For example, the following metadata can be added to a .glb file, to make an object grabbable in AFRAME:
```
+────────────────────────────────────────────────────────────────────────────────────────────────────────+
│ 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' │
│ | │
+────────────────────────────────────────────────────────────────────────────────────────────────────────+
```
* key/value syntax: -`<vendorname>`-`<component|version>`.`<key>` `[string/boolean/float/int]`-value
String-templatevalues are evaluated as per [URI Templates (RFC6570)](https://www.rfc-editor.org/rfc/rfc6570) Level 1.
> This 'separating of mechanism from policy' (unix rule) does **somewhat** 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.
# Security Considerations
(!Security Considerations)
The only dynamic parts are [W3C Media Fragments](https://www.w3.org/TR/media-frags/) and [URI Templates (RFC6570)](https://www.rfc-editor.org/rfc/rfc6570).<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.
# FAQ
(!FAQ )
**Q:** Why is everything HTTP GET-based, what about POST/PUT/DELETE HATEOS<br>
**A:** 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 `src` values)
---
**Q:** Why isn't there support for scripting, URI Template Fragments are so limited compared to WASM & javascript
**A:** 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 [W3C Media Fragments](https://www.w3.org/TR/media-frags/) and [URI Templates (RFC6570)](https://www.rfc-editor.org/rfc/rfc6570), 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).
# authors
(!authors)
* Leon van Kammen (@lvk@mastodon.online)
* Jens Finkhäuser (@jens@social.finkhaeuser.de)
# IANA Considerations
(!IANA Considerations)
This document has no IANA actions.
# Acknowledgments
(!Acknowledgments)
* [NLNET](https://nlnet.nl)
* [Future of Text](https://futureoftext.org)
* [visual-meta.info](https://visual-meta.info)
* Michiel Leenaars
* Gerben van der Broeke
* Mauve
* Jens Finkhäuser
* Marc Belmont
* Tim Gerritsen
* Frode Hegland
* Brandel Zackernuk
* Mark Anderson
# Appendix: Definitions
(!Appendix: Definitions )
|definition | explanation |
|----------------------|--------------------------------------------------------------------------------------------------------------------------------------|
|human | a sentient being who thinks fuzzy, absorbs, and shares thought (by plain text, not markuplanguage) |
|scene | a (local/remote) 3D scene or 3D file (index.gltf e.g.) |
|3D object | an object inside a scene characterized by vertex-, face- and customproperty data. |
|URI | some resource at something somewhere via someprotocol (`http://me.com/foo.glb#foo` or `e76f8efec8efce98e6f` [see interpeer.io](https://interpeer.io))|
|URL | something somewhere via someprotocol (`http://me.com/foo.glb`) |
|URN | something at some domain (`me.com/foo.glb`) |
|metadata | custom properties of text, 3D Scene or Object(nodes), relevant to machines and a human minority (academics/developers) |
|XR fragment | URI Fragment with spatial hints (which match the name of a 3D object-, camera-, animation-object) |
|the XRWG | wordgraph (collapses 3D scene to tags) |
|the hashbus | hashtags map to camera/scene-projections |
|spacetime hashtags | positions camera, triggers scene-preset/time |
|teleportation | repositioning the enduser to a different position (or 3D scene/file) |
|sourceportation | teleporting the enduser to the original XR Document of an `src` embedded object. |
|placeholder object | a 3D object which with src-metadata (which will be replaced by the src-data.) |
|src | (HTML-piggybacked) metadata of a 3D object which instances content |
|href | (HTML-piggybacked) metadata of a 3D object which links to content |
|filter | URI Fragment(s) which show/hide object(s) in a scene based on name/tag/property (`#cube&-price=>3`) |
|visual-meta | [visual-meta](https://visual.meta.info) data appended to text/books/papers which is indirectly visible/editable in XR. |
|requestless metadata | metadata which never spawns new requests (unlike RDF/HTML, which can cause framerate-dropping, hence not used a lot in games) |
|FPS | frames per second in spatial experiences (games,VR,AR e.g.), should be as high as possible |
|introspective | inward sensemaking ("I feel this belongs to that") |
|extrospective | outward sensemaking ("I'm fairly sure John is a person who lives in oklahoma") |
|`◻` | ascii representation of an 3D object/mesh |
|(un)obtrusive | obtrusive: wrapping human text/thought in XML/HTML/JSON obfuscates human text into a salad of machine-symbols and words |
|flat 3D object | a 3D object of which all verticies share a plane |
|BibTeX | simple tagging/citing/referencing standard for plaintext |
|BibTag | a BibTeX tag |
|(hashtag)bibs | an easy to speak/type/scan tagging SDL ([see here](https://github.com/coderofsalvation/hashtagbibs) which expands to BibTex/JSON/XML |

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Title = "XR Fragments"
area = "Internet"
workgroup = "Internet Engineering Task Force"
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value = "draft-XRFRAGMENTS-leonvankammen-00"
stream = "IETF"
status = "informational"
date = 2023-04-12T00:00:00Z
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initials="L.R."
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fullname="L.R. van Kammen"
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stream: IETF
area: Internet
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.# Abstract
This draft offers a specification for 4D URLs & navigation, to link 3D scenes and text together with- or without a network-connection.<br>
The specification promotes spatial addressibility, sharing, navigation, query-ing and tagging interactive (text)objects across for (XR) Browsers.<br>
XR Fragments allows us to enrich existing dataformats, by recursive use of existing proven technologies like [URI Fragments](https://en.wikipedia.org/wiki/URI_fragment) and BibTags notation.<br>
> Almost every idea in this document is demonstrated at [https://xrfragment.org](https://xrfragment.org)
{mainmatter}
# Introduction
How can we add more features to existing text & 3D scenes, without introducing new dataformats?<br>
Historically, there's many attempts to create the ultimate markuplanguage or 3D fileformat.<br>
However, thru the lens of authoring, their lowest common denominator is still: plain text.<br>
XR Fragments allows us to enrich/connect existing dataformats, by recursive use of existing technologies:<br>
1. addressibility and navigation of 3D scenes/objects: [URI Fragments](https://en.wikipedia.org/wiki/URI_fragment) + src/href spatial metadata
1. hasslefree tagging across text and spatial objects using [BibTags](https://en.wikipedia.org/wiki/BibTeX) as appendix (see [visual-meta](https://visual-meta.info) e.g.)
> NOTE: The chapters in this document are ordered from highlevel to lowlevel (technical) as much as possible
# Core principle
XR Fragments strives to serve (nontechnical/fuzzy) humans first, and machine(implementations) later, by ensuring hasslefree text-vs-thought feedback loops.<br>
This also means that the repair-ability of machine-matters should be human friendly too (not too complex).<br>
> "When a car breaks down, the ones **without** turbosupercharger are easier to fix"
Let's always focus on average humans: the 'fuzzy symbolical mind' must be served first, before serving the greater ['categorized typesafe RDF hive mind'](https://en.wikipedia.org/wiki/Borg)).
> Humans first, machines (AI) later.
# Conventions and Definitions
|definition | explanation |
|----------------------|-------------------------------------------------------------------------------------------------------------------------------|
|human | a sentient being who thinks fuzzy, absorbs, and shares thought (by plain text, not markuplanguage) |
|scene | a (local/remote) 3D scene or 3D file (index.gltf e.g.) |
|3D object | an object inside a scene characterized by vertex-, face- and customproperty data. |
|metadata | custom properties of text, 3D Scene or Object(nodes), relevant to machines and a human minority (academics/developers) |
|XR fragment | URI Fragment with spatial hints like `#pos=0,0,0&t=1,100` e.g. |
|src | (HTML-piggybacked) metadata of a 3D object which instances content |
|href | (HTML-piggybacked) metadata of a 3D object which links to content |
|query | an URI Fragment-operator which queries object(s) from a scene like `#q=cube` |
|visual-meta | [visual-meta](https://visual.meta.info) data appended to text/books/papers which is indirectly visible/editable in XR. |
|requestless metadata | opposite of networked metadata (RDF/HTML requests can easily fan out into framerate-dropping, hence not used a lot in games). |
|FPS | frames per second in spatial experiences (games,VR,AR e.g.), should be as high as possible |
|introspective | inward sensemaking ("I feel this belongs to that") |
|extrospective | outward sensemaking ("I'm fairly sure John is a person who lives in oklahoma") |
|`◻` | ascii representation of an 3D object/mesh |
|(un)obtrusive | obtrusive: wrapping human text/thought in XML/HTML/JSON obfuscates human text into a salad of machine-symbols and words |
|BibTeX | simple tagging/citing/referencing standard for plaintext |
|BibTag | a BibTeX tag |
# List of URI Fragments
| fragment | type | example | info |
|--------------|----------|-------------------|-------------------------------------------------------------------|
| `#pos` | vector3 | `#pos=0.5,0,0` | positions camera to xyz-coord 0.5,0,0 |
| `#rot` | vector3 | `#rot=0,90,0` | rotates camera to xyz-coord 0.5,0,0 |
| `#t` | vector2 | `#t=500,1000` | sets animation-loop range between frame 500 and 1000 |
| `#......` | string | `#.cubes` `#cube` | object(s) of interest (fragment to object name or class mapping) |
> xyz coordinates are similar to ones found in SVG Media Fragments
# List of metadata for 3D nodes
| key | type | example (JSON) | info |
|--------------|----------|--------------------|--------------------------------------------------------|
| `name` | string | `"name": "cube"` | available in all 3D fileformats & scenes |
| `class` | string | `"class": "cubes"` | available through custom property in 3D fileformats |
| `href` | string | `"href": "b.gltf"` | available through custom property in 3D fileformats |
| `src` | string | `"src": "#q=cube"` | available through custom property in 3D fileformats |
Popular compatible 3D fileformats: `.gltf`, `.obj`, `.fbx`, `.usdz`, `.json` (THREEjs), `COLLADA` and so on.
> NOTE: XR Fragments are file-agnostic, which means that the metadata exist in programmatic 3D scene(nodes) too.
# Navigating 3D
Here's an ascii representation of a 3D scene-graph which contains 3D objects `◻` and their metadata:
```
+--------------------------------------------------------+
| |
| index.gltf |
| │ |
| ├── ◻ buttonA |
| │ └ href: #pos=1,0,1&t=100,200 |
| │ |
| └── ◻ buttonB |
| └ href: other.fbx | <-- file-agnostic (can be .gltf .obj etc)
| |
+--------------------------------------------------------+
```
An XR Fragment-compatible browser viewing this scene, allows the end-user to interact with the `buttonA` and `buttonB`.<br>
In case of `buttonA` the end-user will be teleported to another location and time in the **current loaded scene**, but `buttonB` will
**replace the current scene** with a new one, like `other.fbx`.
# Embedding 3D content
Here's an ascii representation of a 3D scene-graph with 3D objects `◻` which embeds remote & local 3D objects `◻` (without) using queries:
```
+--------------------------------------------------------+ +-------------------------+
| | | |
| index.gltf | | ocean.com/aquarium.fbx |
| │ | | │ |
| ├── ◻ canvas | | └── ◻ fishbowl |
| │ └ src: painting.png | | ├─ ◻ bass |
| │ | | └─ ◻ tuna |
| ├── ◻ aquariumcube | | |
| │ └ src: ://rescue.com/fish.gltf#q=bass%20tuna | +-------------------------+
| │ |
| ├── ◻ bedroom |
| │ └ src: #q=canvas |
| │ |
| └── ◻ livingroom |
| └ src: #q=canvas |
| |
+--------------------------------------------------------+
```
An XR Fragment-compatible browser viewing this scene, lazy-loads and projects `painting.png` onto the (plane) object called `canvas` (which is copy-instanced in the bed and livingroom).<br>
Also, after lazy-loading `ocean.com/aquarium.gltf`, only the queried objects `bass` and `tuna` will be instanced inside `aquariumcube`.<br>
Resizing will be happen accordingly to its placeholder object `aquariumcube`, see chapter Scaling.<br>
# XR Fragment queries
Include, exclude, hide/shows objects using space-separated strings:
* `#q=cube`
* `#q=cube -ball_inside_cube`
* `#q=* -sky`
* `#q=-.language .english`
* `#q=cube&rot=0,90,0`
* `#q=price:>2 price:<5`
It's simple but powerful syntax which allows <b>css</b>-like class/id-selectors with a searchengine prompt-style feeling:
1. queries are showing/hiding objects **only** when defined as `src` value (prevents sharing of scene-tampered URL's).
1. queries are highlighting objects when defined in the top-Level (browser) URL (bar).
1. search words like `cube` and `foo` in `#q=cube foo` are matched against 3D object names or custom metadata-key(values)
1. search words like `cube` and `foo` in `#q=cube foo` are matched against tags (BibTeX) inside plaintext `src` values like `@cube{redcube, ...` e.g.
1. `#` equals `#q=*`
1. words starting with `.` like `.german` match class-metadata of 3D objects like `"class":"german"`
1. words starting with `.` like `.german` match class-metadata of (BibTeX) tags in XR Text objects like `@german{KarlHeinz, ...` e.g.
> **For example**: `#q=.foo` is a shorthand for `#q=class:foo`, which will select objects with custom property `class`:`foo`. Just a simple `#q=cube` will simply select an object named `cube`.
* see [an example video here](https://coderofsalvation.github.io/xrfragment.media/queries.mp4)
## including/excluding
| operator | info |
|----------|-------------------------------------------------------------------------------------------------------------------------------|
| `*` | select all objects (only useful in `src` custom property) |
| `-` | removes/hides object(s) |
| `:` | indicates an object-embedded custom property key/value |
| `.` | alias for `"class" :".foo"` equals `class:foo` |
| `>` `<` | compare float or int number |
| `/` | reference to root-scene.<br>Useful in case of (preventing) showing/hiding objects in nested scenes (instanced by `src`) (*) |
> \* = `#q=-/cube` hides object `cube` only in the root-scene (not nested `cube` objects)<br> `#q=-cube` hides both object `cube` in the root-scene <b>AND</b> nested `skybox` objects |
[» example implementation](https://github.com/coderofsalvation/xrfragment/blob/main/src/3rd/js/three/xrf/q.js)
[» example 3D asset](https://github.com/coderofsalvation/xrfragment/blob/main/example/assets/query.gltf#L192)
[» discussion](https://github.com/coderofsalvation/xrfragment/issues/3)
## Query Parser
Here's how to write a query parser:
1. create an associative array/object to store query-arguments as objects
1. detect object id's & properties `foo:1` and `foo` (reference regex: `/^.*:[><=!]?/` )
1. detect excluders like `-foo`,`-foo:1`,`-.foo`,`-/foo` (reference regex: `/^-/` )
1. detect root selectors like `/foo` (reference regex: `/^[-]?\//` )
1. detect class selectors like `.foo` (reference regex: `/^[-]?class$/` )
1. detect number values like `foo:1` (reference regex: `/^[0-9\.]+$/` )
1. expand aliases like `.foo` into `class:foo`
1. for every query token split string on `:`
1. create an empty array `rules`
1. then strip key-operator: convert "-foo" into "foo"
1. add operator and value to rule-array
1. therefore we we set `id` to `true` or `false` (false=excluder `-`)
1. and we set `root` to `true` or `false` (true=`/` root selector is present)
1. we convert key '/foo' into 'foo'
1. finally we add the key/value to the store like `store.foo = {id:false,root:true}` e.g.
> An example query-parser (which compiles to many languages) can be [found here](https://github.com/coderofsalvation/xrfragment/blob/main/src/xrfragment/Query.hx)
## XR Fragment URI Grammar
```
reserved = gen-delims / sub-delims
gen-delims = "#" / "&"
sub-delims = "," / "="
```
> Example: `://foo.com/my3d.gltf#pos=1,0,0&prio=-5&t=0,100`
| Demo | Explanation |
|-------------------------------|---------------------------------|
| `pos=1,2,3` | vector/coordinate argument e.g. |
| `pos=1,2,3&rot=0,90,0&q=.foo` | combinators |
# Text in XR (tagging,linking to spatial objects)
We still think and speak in simple text, not in HTML or RDF.<br>
The most advanced human will probably not shout `<h1>FIRE!</h1>` in case of emergency.<br>
Given the new dawn of (non-keyboard) XR interfaces, keeping text as is (not obscuring with markup) is preferred.<br>
Ideally metadata must come **later with** text, but not **obfuscate** the text, or **in another** file.<br>
> Humans first, machines (AI) later ([core principle](#core-principle)
This way:
1. XR Fragments allows <b id="tagging-text">hasslefree XR text tagging</b>, using BibTeX metadata **at the end of content** (like [visual-meta](https://visual.meta.info)).
1. XR Fragments allows hasslefree <a href="#textual-tag">textual tagging</a>, <a href="#spatial-tag">spatial tagging</a>, and <a href="#supra-tagging">supra tagging</a>, by mapping 3D/text object (class)names using BibTeX 'tags'
1. Bibs/BibTeX-appendices is first-choice **requestless metadata**-layer for XR text, HTML/RDF/JSON is great (but fits better in the application-layer)
1. Default font (unless specified otherwise) is a modern monospace font, for maximized tabular expressiveness (see [the core principle](#core-principle)).
1. anti-pattern: hardcoupling a mandatory **obtrusive markuplanguage** or framework with an XR browsers (HTML/VRML/Javascript) (see [the core principle](#core-principle))
1. anti-pattern: limiting human introspection, by immediately funneling human thought into typesafe, precise, pre-categorized metadata like RDF (see [the core principle](#core-principle))
This allows recursive connections between text itself, as well as 3D objects and vice versa, using **BibTags** :
```
+---------------------------------------------+ +------------------+
| My Notes | | / \ |
| | | / \ |
| The houses here are built in baroque style. | | /house\ |
| | | |_____| |
| | +---------|--------+
| @house{houses, >----'house'--------| class/name match?
| url = {#.house} >----'houses'-------` class/name match?
| } |
+---------------------------------------------+
```
> The enduser can add connections by speaking/typing/scanning [hashtagbibs](https://github.com/coderofsalvation/hashtagbibs) which the XR Browser can expand to BibTags.
This allows instant realtime tagging of objects at various scopes:
| scope | matching algo |
|---------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| <b id="textual-tagging">textual</b> | text containing 'houses' is now automatically tagged with 'house' (incl. plaintext `src` child nodes) |
| <b id="spatial-tagging">spatial</b> | spatial object(s) with `"class":"house"` (because of `{#.house}`) are now automatically tagged with 'house' (incl. child nodes) |
| <b id="supra-tagging">supra</b> | text- or spatial-object(s) (non-descendant nodes) elsewhere, named 'house', are automatically tagged with 'house' (current node to root node) |
| <b id="omni-tagging">omni</b> | text- or spatial-object(s) (non-descendant nodes) elsewhere, containing class/name 'house', are automatically tagged with 'house' (too node to all nodes) |
| <b id="infinite-tagging">infinite</b> | text- or spatial-object(s) (non-descendant nodes) elsewhere, containing class/name 'house' or 'houses', are automatically tagged with 'house' (too node to all nodes) |
This empowers the enduser spatial expressiveness (see [the core principle](#core-principle)): spatial wires can be rendered, words can be highlighted, spatial objects can be highlighted/moved/scaled, links can be manipulated by the user.<br>
The simplicity of appending BibTeX 'tags' (humans first, machines later) is also demonstrated by [visual-meta](https://visual-meta.info) in greater detail.
1. The XR Browser needs to adjust tag-scope based on the endusers needs/focus (infinite tagging only makes sense when environment is scaled down significantly)
1. The XR Browser should always allow the human to view/edit the metadata, by clicking 'toggle metadata' on the 'back' (contextmenu e.g.) of any XR text, anywhere anytime.
> NOTE: infinite matches both 'house' and 'houses' in text, as well as spatial objects with `"class":"house"` or name "house". This multiplexing of id/category is deliberate because of [the core principle](#core-principle).
## Default Data URI mimetype
The `src`-values work as expected (respecting mime-types), however:
The XR Fragment specification bumps the traditional default browser-mimetype
`text/plain;charset=US-ASCII`
to a hashtagbib(tex)-friendly one:
`text/plain;charset=utf-8;bib=^@`
This indicates that:
* utf-8 is supported by default
* [hashtagbibs](https://github.com/coderofsalvation/hashtagbibs) are expanded to [bibtags](https://en.wikipedia.org/wiki/BibTeX)
* lines matching regex `^@` will automatically get filtered out, in order to:
* links between textual/spatial objects can automatically be detected
* bibtag appendices ([visual-meta](https://visual-meta.info) can be interpreted e.g.
> for more info on this mimetype see [bibs](https://github.com/coderofsalvation/hashtagbibs)
Advantages:
* out-of-the-box (de)multiplex human text and metadata in one go (see [the core principle](#core-principle))
* no network-overhead for metadata (see [the core principle](#core-principle))
* ensuring high FPS: HTML/RDF historically is too 'requesty'/'parsy' for game studios
* rich send/receive/copy-paste everywhere by default, metadata being retained (see [the core principle](#core-principle))
* netto result: less webservices, therefore less servers, and overall better FPS in XR
> This significantly expands expressiveness and portability of human tagged text, by **postponing machine-concerns to the end of the human text** in contrast to literal interweaving of content and markupsymbols (or extra network requests, webservices e.g.).
For all other purposes, regular mimetypes can be used (but are not required by the spec).<br>
## URL and Data URI
```
+--------------------------------------------------------------+ +------------------------+
| | | author.com/article.txt |
| index.gltf | +------------------------+
| │ | | |
| ├── ◻ article_canvas | | Hello friends. |
| │ └ src: ://author.com/article.txt | | |
| │ | | @friend{friends |
| └── ◻ note_canvas | | ... |
| └ src:`data:welcome human\n@...` | | } |
| | +------------------------+
| |
+--------------------------------------------------------------+
```
The enduser will only see `welcome human` and `Hello friends` rendered spatially.
The beauty is that text (AND visual-meta) in Data URI promotes rich copy-paste.
In both cases, the text gets rendered immediately (onto a plane geometry, hence the name '_canvas').
The XR Fragment-compatible browser can let the enduser access visual-meta(data)-fields after interacting with the object (contextmenu e.g.).
> additional tagging using [bibs](https://github.com/coderofsalvation/hashtagbibs): to tag spatial object `note_canvas` with 'todo', the enduser can type or speak `@note_canvas@todo`
The mapping between 3D objects and text (src-data) is simple (the :
Example:
```
+------------------------------------------------+
| |
| index.gltf |
| │ |
| └── ◻ rentalhouse |
| └ class: house <----------------- matches -------+
| └ ◻ note | |
| └ src:`data: todo: call owner | hashtagbib |
| #owner@house@todo | ----> expands to @house{owner,
| | bibtex: }
| ` | @contact{
+------------------------------------------------+ }
```
Bi-directional mapping between 3D object names and/or classnames and text using bibs,BibTags & XR Fragments, allows for rich interlinking between text and 3D objects:
1. When the user surfs to https://.../index.gltf#rentalhouse the XR Fragments-parser points the enduser to the rentalhouse object, and can show contextual info about it.
2. When (partial) remote content is embedded thru XR Fragment queries (see XR Fragment queries), indirectly related metadata can be embedded along.
## Bibs & BibTeX: lowest common denominator for linking data
> "When a car breaks down, the ones **without** turbosupercharger are easier to fix"
Unlike XML or JSON, BibTex is typeless, unnested, and uncomplicated, hence a great advantage for introspection.<br>
It's a missing sensemaking precursor to extrospective RDF.<br>
BibTeX-appendices are already used in the digital AND physical world (academic books, [visual-meta](https://visual-meta.info)), perhaps due to its terseness & simplicity.<br>
In that sense, it's one step up from the `.ini` fileformat (which has never leaked into the physical world like BibTex):
1. <b id="frictionless-copy-paste">frictionless copy/pasting</b> (by humans) of (unobtrusive) content AND metadata
1. an introspective 'sketchpad' for metadata, which can (optionally) mature into RDF later
| characteristic | UTF8 Plain Text (with BibTeX) | RDF |
|------------------------------------|-------------------------------|---------------------------|
| perspective | introspective | extrospective |
| structure | fuzzy (sensemaking) | precise |
| space/scope | local | world |
| everything is text (string) | yes | no |
| voice/paper-friendly | [bibs](https://github.com/coderofsalvation/hashtagbibs) | no |
| leaves (dictated) text intact | yes | no |
| markup language | just an appendix | ~4 different |
| polyglot format | no | yes |
| easy to copy/paste content+metadata| yes | up to application |
| easy to write/repair for layman | yes | depends |
| easy to (de)serialize | yes (fits on A4 paper) | depends |
| infrastructure | selfcontained (plain text) | (semi)networked |
| freeform tagging/annotation | yes, terse | yes, verbose |
| can be appended to text-content | yes | up to application |
| copy-paste text preserves metadata | yes | up to application |
| emoji | yes | depends on encoding |
| predicates | free | semi pre-determined |
| implementation/network overhead | no | depends |
| used in (physical) books/PDF | yes (visual-meta) | no |
| terse non-verb predicates | yes | no |
| nested structures | no (but: BibTex rulers) | yes |
> To keep XR Fragments a lightweight spec, BibTeX is used for rudimentary text/spatial tagging (not JSON, RDF or a scripting language because they're harder to write/speak/repair.).
Applications are also free to attach any JSON(LD / RDF) to spatial objects using custom properties (but is not interpreted by this spec).
## XR Text example parser
1. The XR Fragments spec does not aim to harden the BiBTeX format
2. respect multi-line BibTex values because of [the core principle](#core-principle)
3. Expand hashtag(bibs) and rulers (like `${visual-meta-start}`) according to the [hashtagbibs spec](https://github.com/coderofsalvation/hashtagbibs)
4. BibTeX snippets should always start in the beginning of a line (regex: ^@), hence mimetype `text/plain;charset=utf-8;bib=^@`
Here's an XR Text (de)multiplexer in javascript, which ticks all the above boxes:
```
xrtext = {
expandBibs: (text) => {
let bibs = { regex: /(#[a-zA-Z0-9_+@\-]+(#)?)/g, tags: {}}
text.replace( bibs.regex , (m,k,v) => {
tok = m.substr(1).split("@")
match = tok.shift()
if( tok.length ) tok.map( (t) => bibs.tags[t] = `@${t}{${match},\n}` )
else if( match.substr(-1) == '#' )
bibs.tags[match] = `@{${match.replace(/#/,'')}}`
else bibs.tags[match] = `@${match}{${match},\n}`
})
return text.replace( bibs.regex, '') + Object.values(bibs.tags).join('\n')
},
decode: (str) => {
// bibtex: ↓@ ↓<tag|tag{phrase,|{ruler}> ↓property ↓end
let pat = [ /@/, /^\S+[,{}]/, /},/, /}/ ]
let tags = [], text='', i=0, prop=''
let lines = xrtext.expandBibs(str).replace(/\r?\n/g,'\n').split(/\n/)
for( let i = 0; i < lines.length && !String(lines[i]).match( /^@/ ); i++ )
text += lines[i]+'\n'
bibtex = lines.join('\n').substr( text.length )
bibtex.split( pat[0] ).map( (t) => {
try{
let v = {}
if( !(t = t.trim()) ) return
if( tag = t.match( pat[1] ) ) tag = tag[0]
if( tag.match( /^{.*}$/ ) ) return tags.push({ruler:tag})
t = t.substr( tag.length )
t.split( pat[2] )
.map( kv => {
if( !(kv = kv.trim()) || kv == "}" ) return
v[ kv.match(/\s?(\S+)\s?=/)[1] ] = kv.substr( kv.indexOf("{")+1 )
})
tags.push( { k:tag, v } )
}catch(e){ console.error(e) }
})
return {text, tags}
},
encode: (text,tags) => {
let str = text+"\n"
for( let i in tags ){
let item = tags[i]
if( item.ruler ){
str += `@${item.ruler}\n`
continue;
}
str += `@${item.k}\n`
for( let j in item.v ) str += ` ${j} = {${item.v[j]}}\n`
str += `}\n`
}
return str
}
}
```
The above functions (de)multiplexe text/metadata, expands bibs, (de)serialize bibtex (and all fits more or less on one A4 paper)
> above can be used as a startingpoint for LLVM's to translate/steelman to a more formal form/language.
```
str = `
hello world
here are some hashtagbibs followed by bibtex:
#world
#hello@greeting
#another-section#
@{some-section}
@flap{
asdf = {23423}
}`
var {tags,text} = xrtext.decode(str) // demultiplex text & bibtex
tags.find( (t) => t.k == 'flap{' ).v.asdf = 1 // edit tag
tags.push({ k:'bar{', v:{abc:123} }) // add tag
console.log( xrtext.encode(text,tags) ) // multiplex text & bibtex back together
```
This expands to the following (hidden by default) BibTex appendix:
```
hello world
here are some hashtagbibs followed by bibtex:
@{some-section}
@flap{
asdf = {1}
}
@world{world,
}
@greeting{hello,
}
@{another-section}
@bar{
abc = {123}
}
```
# HYPER copy/paste
The previous example, offers something exciting compared to simple copy/paste of 3D objects or text.
XR Text according to the XR Fragment spec, allows HYPER-copy/paste: time, space and text interlinked.
Therefore, the enduser in an XR Fragment-compatible browser can copy/paste/share data in these ways:
1. time/space: 3D object (current animation-loop)
1. text: TeXt object (including BibTeX/visual-meta if any)
1. interlinked: Collected objects by visual-meta tag
# Security Considerations
Since XR Text contains metadata too, the user should be able to set up tagging-rules, so the copy-paste feature can :
* filter out sensitive data when copy/pasting (XR text with `class:secret` e.g.)
# IANA Considerations
This document has no IANA actions.
# Acknowledgments
TODO acknowledge.

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<!DOCTYPE html>
<html>
<head>
<title>XR Macros</title>
<meta name="GENERATOR" content="github.com/mmarkdown/mmark Mmark Markdown Processor - mmark.miek.nl">
<meta charset="utf-8">
</head>
<body>
<!-- for annotated version see: https://raw.githubusercontent.com/ietf-tools/rfcxml-templates-and-schemas/main/draft-rfcxml-general-template-annotated-00.xml -->
<style type="text/css">
body{
font-family: monospace;
max-width: 1000px;
font-size: 15px;
padding: 0% 20%;
line-height: 30px;
color:#555;
background:#F0F0F3
}
h1 { margin-top:40px; }
pre{ line-height:18px; }
a,a:visited,a:active{ color: #70f; }
code{
border: 1px solid #AAA;
border-radius: 3px;
padding: 0px 5px 2px 5px;
}
pre{
line-height: 18px;
overflow: auto;
padding: 12px;
}
pre + code {
background:#DDD;
}
pre>code{
border:none;
border-radius:0px;
padding:0;
}
blockquote{
padding-left: 30px;
margin: 0;
border-left: 5px solid #CCC;
}
th {
border-bottom: 1px solid #000;
text-align: left;
padding-right:45px;
padding-left:7px;
background: #DDD;
}
td {
border-bottom: 1px solid #CCC;
font-size:13px;
}
</style>
<br>
<h1>XR Macros</h1>
<br>
<pre>
stream: IETF
area: Internet
status: informational
author: Leon van Kammen
date: 2023-04-12T00:00:00Z
workgroup: Internet Engineering Task Force
value: draft-XRMACROS-leonvankammen-00
</pre>
<h1 class="special" id="abstract">Abstract</h1>
<p>This draft offers a specification for embedding macros in existing 3D scenes/assets, to offer simple interactions and configure the renderer further.<br>
Together with URI Fragments, it allows for rich immersive experiences without the need of a complicated sandboxed scripting languages.</p>
<blockquote>
<p>Almost every idea in this document is demonstrated at <a href="https://xrfragment.org">https://xrfragment.org</a>, as this spec was created during the <a href="https://xrfragment.org">XR Fragments</a> spec.</p>
</blockquote>
<section data-matter="main">
<h1 id="introduction">Introduction</h1>
<p>How can we add more features to existing text &amp; 3D scenes, without introducing new dataformats?<br>
Historically, there&rsquo;s many attempts to create the ultimate markuplanguage or 3D fileformat.<br>
Their lowest common denominator is: (co)authoring using plain text.<br>
Therefore, XR Macros allows us to enrich/connect existing dataformats, by offering a polyglot notation based on existing notations:<br></p>
<ol>
<li>getting/setting common used 3D properties using querystring- or JSON-notation</li>
<li>targeting 3D properties using the lightweight query notation present in <a href="https://xrfragment.org">XR Fragments</a></li>
</ol>
<blockquote>
<p>NOTE: The chapters in this document are ordered from highlevel to lowlevel (technical) as much as possible</p>
</blockquote>
<h1 id="core-principle">Core principle</h1>
<ol>
<li>XR Macros use querystrings, but are HTML-agnostic (though pseudo-XR Fragment browsers <strong>can</strong> be implemented on top of HTML/Javascript).</li>
<li>An XR Macro is 3D metadata which starts with &lsquo;!&rsquo; (<code>!clickme: fog=0,10</code> e.g.)</li>
<li>Metadata-values can contain the <code>|</code> symbol to 🎲 roundrobin variable values (<code>!toggleme: fog=0,10|fog=0,1000</code> e.g.)</li>
<li>XR Macros acts as simple eventhandlers for URI Fragments: they are automatically published on the (<a href="https://xrfragment.org">XR Fragments</a>) hashbus, to act as events (so more serious scripting languages can react to them as well).</li>
<li>XR Macros can assign object metadata (<code>!setlocal: foo=1</code> writes <code>foo:1</code> metadata to the object containing the <code>!setlocal</code> metadata)</li>
<li>XR Macros can assign global metadata (<code>!setfoo: #foo=1</code> writes <code>foo:1</code> metadata to the root scene-node)</li>
</ol>
<blockquote>
<p>These very simple principles allow for rich interactions and dynamic querying</p>
</blockquote>
<h1 id="conventions-and-definitions">Conventions and Definitions</h1>
<p>See appendix below in case certain terms are not clear.</p>
<h1 id="list-of-xr-macros">List of XR Macros</h1>
<p>(XR) Macros can be embedded in 3D assets/scenes.<br>
Macros enrich existing spatial content with a lowcode, limited logic-layer, by recursive (economic) use of the querystring syntax (which search engines and <a href="https://xrfragment.org">XR Fragments</a> already uses.<br>
This is done by allowing string/integer variables, and the <code>|</code> symbol to roundrobin variable values.<br>
Macros also act as events, so more serious scripting languages can react to them as well.<br></p>
<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><code>@bg</code></td>
<td>string</td>
<td><code>&quot;@bg&quot;:&quot;#cube&quot;</code></td>
<td>bg: binds fog near/far based to cube x/y/z (anim) values</td>
<td>custom property in 3D fileformats</td>
</tr>
<tr>
<td><code>@fog</code></td>
<td>string</td>
<td><code>&quot;@fog&quot;:&quot;#cube&quot;</code></td>
<td>fog: binds fog near/far based to cube x/y (anim) values</td>
<td>custom property in 3D fileformats</td>
</tr>
<tr>
<td><code>@scroll</code></td>
<td>string</td>
<td><code>&quot;@scroll&quot;:&quot;#cube&quot;</code></td>
<td>texturescrolling: binds texture x/y/rot based to cube x/y/z (anim) values</td>
<td>custom property in 3D fileformats</td>
</tr>
<tr>
<td><code>@emissive</code></td>
<td>string</td>
<td><code>&quot;@emissive&quot;:&quot;#cube&quot;</code></td>
<td>day/night/mood: binds material&rsquo;s emissive value to cube x/y/z (anim) values</td>
<td>custom property in 3D fileformats</td>
</tr>
</tbody>
</table>
<h2 id="usecase-click-object">Usecase: click object</h2>
<table>
<thead>
<tr>
<th>custom property</th>
<th>value</th>
<th>trigger when</th>
</tr>
</thead>
<tbody>
<tr>
<td>!clickme</td>
<td>bg=1,1,1&amp;foo=2</td>
<td>object clicked</td>
</tr>
</tbody>
</table>
<h2 id="usecase-conditional-click-object">Usecase: conditional click object</h2>
<table>
<thead>
<tr>
<th>custom property</th>
<th>value</th>
<th>trigger when</th>
</tr>
</thead>
<tbody>
<tr>
<td>#</td>
<td>foo=1</td>
<td>scene</td>
</tr>
<tr>
<td>!clickme</td>
<td>q=foo&gt;2&amp;bg=1,1,1</td>
<td>object clicked and foo &gt; 2</td>
</tr>
</tbody>
</table>
<blockquote>
<p>when a user clicks an object with the custom properties above, it should set the backgroundcolor to <code>1,1,1</code> when <code>foo</code> is greater than <code>2</code> (see previous example)</p>
</blockquote>
<h2 id="usecase-click-object-roundrobin">Usecase: click object (roundrobin)</h2>
<table>
<thead>
<tr>
<th>custom property</th>
<th>value</th>
<th>trigger when</th>
</tr>
</thead>
<tbody>
<tr>
<td>!cycleme</td>
<td>day|noon|night</td>
<td>object clicked</td>
</tr>
<tr>
<td>day</td>
<td>bg=1,1,1</td>
<td>roundrobin</td>
</tr>
<tr>
<td>noon</td>
<td>bg=0.5,0.5,0.5</td>
<td>roundrobin</td>
</tr>
<tr>
<td>night</td>
<td>bg=0,0,0&amp;foo=2</td>
<td>roundrobin</td>
</tr>
</tbody>
</table>
<blockquote>
<p>when a user clicks an object with the custom properties above, it should trigger either <code>day</code> <code>noon</code> or <code>night</code> in roundrobin fashion.</p>
</blockquote>
<h2 id="usecase-click-object-or-uri-fragment-and-scene-load-trigger">Usecase: click object or URI fragment, and scene load trigger</h2>
<table>
<thead>
<tr>
<th>custom property</th>
<th>value</th>
<th>trigger when</th>
</tr>
</thead>
<tbody>
<tr>
<td>#</td>
<td>random</td>
<td>scene loaded</td>
</tr>
<tr>
<td>#random</td>
<td>random</td>
<td>URL contains #random</td>
</tr>
<tr>
<td>!random</td>
<td>day|noon|night</td>
<td>#random, # or click</td>
</tr>
<tr>
<td>day</td>
<td>bg=1,1,1</td>
<td>roundrobin</td>
</tr>
<tr>
<td>noon</td>
<td>bg=0.5,0.5,0.5</td>
<td>roundrobin</td>
</tr>
<tr>
<td>night</td>
<td>bg=0,0,0&amp;foo=2</td>
<td>roundrobin</td>
</tr>
</tbody>
</table>
<h2 id="usecase-present-context-menu-with-options">Usecase: present context menu with options</h2>
<table>
<thead>
<tr>
<th>custom property</th>
<th>value</th>
<th>trigger when</th>
</tr>
</thead>
<tbody>
<tr>
<td>!random</td>
<td>!day</td>
<td>!noon</td>
</tr>
<tr>
<td>!day</td>
<td>bg=1,1,1</td>
<td>clicked in contextmenu</td>
</tr>
<tr>
<td>!noon</td>
<td>bg=0.5,0.5,0.5</td>
<td>clicked in contextmenu</td>
</tr>
<tr>
<td>!night</td>
<td>bg=0,0,0&amp;foo=2</td>
<td>clicked in contextmenu</td>
</tr>
</tbody>
</table>
<blockquote>
<p>When interacting with an object with more than one <code>!</code>-macro, the XR Browser should offer a contextmenu to execute a macro.</p>
</blockquote>
<p>In a similar way, when <strong>any</strong> <code>!</code>-macro is present on the sceneroot, the XR Browser should offer a context-menu to execute those macro&rsquo;s.</p>
<h2 id="event-bubble-flow">Event Bubble-flow</h2>
<p>click object with (<code>!clickme</code>:<code>AR</code> or <code>!clickme</code>: <code>!reset</code> e.g.)</p>
<pre><code>
└── does current object contain this property-key (`AR` or `!reset` e.g.)?
└── no: is there any (root)object containing property `AR`
└── yes: evaluate its (roundrobin) XR macro-value(s) (and exit)
└── no: trigger URL: #AR
</code></pre>
<p>click object with (<code>!clickme</code>:<code>#AR|#VR</code> e.g.)</p>
<pre><code>
└── apply the roundrobin (rotate the options, value `#AR` becomes `#VR` upon next click)
└── is there any object with property-key (`#AR` e.g.)?
└── no: just update the URL to `#AR`
└── yes: apply its value to the scene, and update the URL to `#AR`
click object with (`!clickme`:`!foo|!bar|!flop` e.g.)
</code></pre>
<p>
<br>
└── apply the roundrobin (rotate the options, value <code>!foo</code> becomes <code>!bar</code> upon next click)
└── is there any object with property-key (<code>!foo</code> e.g.)?
└── no: do nothing
└── yes: apply its value to the scene
&ldquo;`</p>
<blockquote>
<p>Note that only macro&rsquo;s can trigger roundrobin values or contextmenu&rsquo;s, as well as roundrobin values never ending up in the toplevel URL.</p>
</blockquote>
<h1 id="security-considerations">Security Considerations</h1>
<h1 id="iana-considerations">IANA Considerations</h1>
<p>This document has no IANA actions.</p>
<h1 id="acknowledgments">Acknowledgments</h1>
<ul>
<li><a href="https://nlnet.nl">NLNET</a></li>
<li><a href="https://futureoftext.org">Future of Text</a></li>
<li><a href="https://visual-meta.info">visual-meta.info</a></li>
</ul>
<h1 id="appendix-definitions">Appendix: Definitions</h1>
<table>
<thead>
<tr>
<th>definition</th>
<th>explanation</th>
</tr>
</thead>
<tbody>
<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>XR fragments</td>
<td>URI Fragment with spatial hints like <code>#pos=0,0,0&amp;t=1,100</code> e.g.</td>
</tr>
<tr>
<td>query</td>
<td>an URI Fragment-operator which queries object(s) from a scene like <code>#q=cube</code></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><code></code></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>
</tbody>
</table>
</section>
</body>
</html>

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area = "Internet"
workgroup = "Internet Engineering Task Force"
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value = "draft-XRMACROS-leonvankammen-00"
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status = "informational"
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<h1>XR Macros</h1>
<br>
<pre>
stream: IETF
area: Internet
status: informational
author: Leon van Kammen
date: 2023-04-12T00:00:00Z
workgroup: Internet Engineering Task Force
value: draft-XRMACROS-leonvankammen-00
</pre>
}-->
.# Abstract
This draft offers a specification for embedding macros in existing 3D scenes/assets, to offer simple interactions and configure the renderer further.<br>
Together with URI Fragments, it allows for rich immersive experiences without the need of a complicated sandboxed scripting languages.
> Almost every idea in this document is demonstrated at [https://xrfragment.org](https://xrfragment.org), as this spec was created during the [XR Fragments](https://xrfragment.org) spec.
{mainmatter}
# Introduction
How can we add more features to existing text & 3D scenes, without introducing new dataformats?<br>
Historically, there's many attempts to create the ultimate markuplanguage or 3D fileformat.<br>
Their lowest common denominator is: (co)authoring using plain text.<br>
Therefore, XR Macros allows us to enrich/connect existing dataformats, by offering a polyglot notation based on existing notations:<br>
1. getting/setting common used 3D properties using querystring- or JSON-notation
1. targeting 3D properties using the lightweight query notation present in [XR Fragments](https://xrfragment.org)
> NOTE: The chapters in this document are ordered from highlevel to lowlevel (technical) as much as possible
# Core principle
1. XR Macros use querystrings, but are HTML-agnostic (though pseudo-XR Fragment browsers **can** be implemented on top of HTML/Javascript).
1. An XR Macro is 3D metadata which starts with '!' (`!clickme: fog=0,10` e.g.)
1. Metadata-values can contain the `|` symbol to 🎲 roundrobin variable values (`!toggleme: fog=0,10|fog=0,1000` e.g.)
1. XR Macros acts as simple eventhandlers for URI Fragments: they are automatically published on the ([XR Fragments](https://xrfragment.org)) hashbus, to act as events (so more serious scripting languages can react to them as well).
1. XR Macros can assign object metadata (`!setlocal: foo=1` writes `foo:1` metadata to the object containing the `!setlocal` metadata)
1. XR Macros can assign global metadata (`!setfoo: #foo=1` writes `foo:1` metadata to the root scene-node)
> These very simple principles allow for rich interactions and dynamic querying
# Conventions and Definitions
See appendix below in case certain terms are not clear.
# List of XR Macros
(XR) Macros can be embedded in 3D assets/scenes.<br>
Macros enrich existing spatial content with a lowcode, limited logic-layer, by recursive (economic) use of the querystring syntax (which search engines and [XR Fragments](https://xrfragment.org) already uses.<br>
This is done by allowing string/integer variables, and the `|` symbol to roundrobin variable values.<br>
Macros also act as events, so more serious scripting languages can react to them as well.<br>
| key | type | example (JSON) | function | existing compatibility |
|--------------|----------|------------------------|---------------------|----------------------------------------|
| `@bg` | string | `"@bg":"#cube"` | bg: binds fog near/far based to cube x/y/z (anim) values | custom property in 3D fileformats |
| `@fog` | string | `"@fog":"#cube"` | fog: binds fog near/far based to cube x/y (anim) values | custom property in 3D fileformats |
| `@scroll` | string | `"@scroll":"#cube"` | texturescrolling: binds texture x/y/rot based to cube x/y/z (anim) values | custom property in 3D fileformats |
| `@emissive` | string | `"@emissive":"#cube"` | day/night/mood: binds material's emissive value to cube x/y/z (anim) values | custom property in 3D fileformats |
## Usecase: click object
| custom property | value | trigger when |
|-----------------|--------------------------|------------------------|
| !clickme | bg=1,1,1&foo=2 | object clicked |
## Usecase: conditional click object
| custom property | value | trigger when |
|-----------------|--------------------------|-----------------------------|
| # | foo=1 | scene |
| !clickme | q=foo>2&bg=1,1,1 | object clicked and foo > 2 |
> when a user clicks an object with the custom properties above, it should set the backgroundcolor to `1,1,1` when `foo` is greater than `2` (see previous example)
## Usecase: click object (roundrobin)
| custom property | value | trigger when |
|-----------------|--------------------------|------------------------|
| !cycleme | day&#124;noon&#124;night | object clicked |
| day | bg=1,1,1 | roundrobin |
| noon | bg=0.5,0.5,0.5 | roundrobin |
| night | bg=0,0,0&foo=2 | roundrobin |
> when a user clicks an object with the custom properties above, it should trigger either `day` `noon` or `night` in roundrobin fashion.
## Usecase: click object or URI fragment, and scene load trigger
| custom property | value | trigger when |
|-----------------|--------------------------|------------------------|
| # | random | scene loaded |
| #random | random | URL contains #random |
| !random | day&#124;noon&#124;night | #random, # or click |
| day | bg=1,1,1 | roundrobin |
| noon | bg=0.5,0.5,0.5 | roundrobin |
| night | bg=0,0,0&foo=2 | roundrobin |
## Usecase: present context menu with options
| custom property | value | trigger when |
|-----------------|--------------------------|------------------------|
| !random | !day|!noon|!night | clicked in contextmenu |
| !day | bg=1,1,1 | clicked in contextmenu |
| !noon | bg=0.5,0.5,0.5 | clicked in contextmenu |
| !night | bg=0,0,0&foo=2 | clicked in contextmenu |
> When interacting with an object with more than one `!`-macro, the XR Browser should offer a contextmenu to execute a macro.
In a similar way, when **any** `!`-macro is present on the sceneroot, the XR Browser should offer a context-menu to execute those macro's.
## Event Bubble-flow
click object with (`!clickme`:`AR` or `!clickme`: `!reset` e.g.)
```
└── does current object contain this property-key (`AR` or `!reset` e.g.)?
└── no: is there any (root)object containing property `AR`
└── yes: evaluate its (roundrobin) XR macro-value(s) (and exit)
└── no: trigger URL: #AR
```
click object with (`!clickme`:`#AR|#VR` e.g.)
```
└── apply the roundrobin (rotate the options, value `#AR` becomes `#VR` upon next click)
└── is there any object with property-key (`#AR` e.g.)?
└── no: just update the URL to `#AR`
└── yes: apply its value to the scene, and update the URL to `#AR`
click object with (`!clickme`:`!foo|!bar|!flop` e.g.)
```
└── apply the roundrobin (rotate the options, value `!foo` becomes `!bar` upon next click)
└── is there any object with property-key (`!foo` e.g.)?
└── no: do nothing
└── yes: apply its value to the scene
```
> Note that only macro's can trigger roundrobin values or contextmenu's, as well as roundrobin values never ending up in the toplevel URL.
# Security Considerations
# IANA Considerations
This document has no IANA actions.
# Acknowledgments
* [NLNET](https://nlnet.nl)
* [Future of Text](https://futureoftext.org)
* [visual-meta.info](https://visual-meta.info)
# Appendix: Definitions
|definition | explanation |
|----------------------|-------------------------------------------------------------------------------------------------------------------------------|
|scene | a (local/remote) 3D scene or 3D file (index.gltf e.g.) |
|3D object | an object inside a scene characterized by vertex-, face- and customproperty data. |
|XR fragments | URI Fragment with spatial hints like `#pos=0,0,0&t=1,100` e.g. |
|query | an URI Fragment-operator which queries object(s) from a scene like `#q=cube` |
|FPS | frames per second in spatial experiences (games,VR,AR e.g.), should be as high as possible |
|`◻` | ascii representation of an 3D object/mesh |
|(un)obtrusive | obtrusive: wrapping human text/thought in XML/HTML/JSON obfuscates human text into a salad of machine-symbols and words |

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Internet Engineering Task Force L.R. van Kammen
Internet-Draft 1 September 2025
Intended status: Informational
XR Macros
draft-XRMACROS-leonvankammen-00
Abstract
This draft offers a specification for embedding macros in existing 3D
scenes/assets, to offer simple interactions and configure the
renderer further.
Together with URI Fragments, it allows for rich immersive experiences
without the need of a complicated sandboxed scripting languages.
Almost every idea in this document is demonstrated at
https://xrfragment.org (https://xrfragment.org), as this spec was
created during the XR Fragments (https://xrfragment.org) spec.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 5 March 2026.
Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
van Kammen Expires 5 March 2026 [Page 1]
Internet-Draft XR Macros September 2025
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Core principle . . . . . . . . . . . . . . . . . . . . . . . 2
3. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
4. List of XR Macros . . . . . . . . . . . . . . . . . . . . . . 3
4.1. Usecase: click object . . . . . . . . . . . . . . . . . . 4
4.2. Usecase: conditional click object . . . . . . . . . . . . 4
4.3. Usecase: click object (roundrobin) . . . . . . . . . . . 5
4.4. Usecase: click object or URI fragment, and scene load
trigger . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.5. Usecase: present context menu with options . . . . . . . 6
4.6. Event Bubble-flow . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7
8. Appendix: Definitions . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
How can we add more features to existing text & 3D scenes, without
introducing new dataformats?
Historically, there's many attempts to create the ultimate
markuplanguage or 3D fileformat.
Their lowest common denominator is: (co)authoring using plain text.
Therefore, XR Macros allows us to enrich/connect existing
dataformats, by offering a polyglot notation based on existing
notations:
1. getting/setting common used 3D properties using querystring- or
JSON-notation
2. targeting 3D properties using the lightweight query notation
present in XR Fragments (https://xrfragment.org)
| NOTE: The chapters in this document are ordered from highlevel to
| lowlevel (technical) as much as possible
2. Core principle
1. XR Macros use querystrings, but are HTML-agnostic (though pseudo-
XR Fragment browsers *can* be implemented on top of HTML/
Javascript).
2. An XR Macro is 3D metadata which starts with '!' (!clickme:
fog=0,10 e.g.)
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3. Metadata-values can contain the | symbol to 🎲 roundrobin variable
values (!toggleme: fog=0,10|fog=0,1000 e.g.)
4. XR Macros acts as simple eventhandlers for URI Fragments: they
are automatically published on the (XR Fragments
(https://xrfragment.org)) hashbus, to act as events (so more
serious scripting languages can react to them as well).
5. XR Macros can assign object metadata (!setlocal: foo=1 writes
foo:1 metadata to the object containing the !setlocal metadata)
6. XR Macros can assign global metadata (!setfoo: #foo=1 writes
foo:1 metadata to the root scene-node)
| These very simple principles allow for rich interactions and
| dynamic querying
3. Conventions and Definitions
See appendix below in case certain terms are not clear.
4. List of XR Macros
(XR) Macros can be embedded in 3D assets/scenes.
Macros enrich existing spatial content with a lowcode, limited logic-
layer, by recursive (economic) use of the querystring syntax (which
search engines and XR Fragments (https://xrfragment.org) already
uses.
This is done by allowing string/integer variables, and the | symbol
to roundrobin variable values.
Macros also act as events, so more serious scripting languages can
react to them as well.
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+=========+======+===================+=================+=============+
|key |type |example (JSON) |function |existing |
| | | | |compatibility|
+=========+======+===================+=================+=============+
|@bg |string|"@bg":"#cube" |bg: binds fog |custom |
| | | |near/far based to|property in |
| | | |cube x/y/z (anim)|3D |
| | | |values |fileformats |
+---------+------+-------------------+-----------------+-------------+
|@fog |string|"@fog":"#cube" |fog: binds fog |custom |
| | | |near/far based to|property in |
| | | |cube x/y (anim) |3D |
| | | |values |fileformats |
+---------+------+-------------------+-----------------+-------------+
|@scroll |string|"@scroll":"#cube" |texturescrolling:|custom |
| | | |binds texture |property in |
| | | |x/y/rot based to |3D |
| | | |cube x/y/z (anim)|fileformats |
| | | |values | |
+---------+------+-------------------+-----------------+-------------+
|@emissive|string|"@emissive":"#cube"|day/night/mood: |custom |
| | | |binds material's |property in |
| | | |emissive value to|3D |
| | | |cube x/y/z (anim)|fileformats |
| | | |values | |
+---------+------+-------------------+-----------------+-------------+
Table 1
4.1. Usecase: click object
+=================+================+================+
| custom property | value | trigger when |
+=================+================+================+
| !clickme | bg=1,1,1&foo=2 | object clicked |
+-----------------+----------------+----------------+
Table 2
4.2. Usecase: conditional click object
+=================+==================+============================+
| custom property | value | trigger when |
+=================+==================+============================+
| # | foo=1 | scene |
+-----------------+------------------+----------------------------+
| !clickme | q=foo>2&bg=1,1,1 | object clicked and foo > 2 |
+-----------------+------------------+----------------------------+
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Table 3
| when a user clicks an object with the custom properties above, it
| should set the backgroundcolor to 1,1,1 when foo is greater than 2
| (see previous example)
4.3. Usecase: click object (roundrobin)
+=================+================+================+
| custom property | value | trigger when |
+=================+================+================+
| !cycleme | day|noon|night | object clicked |
+-----------------+----------------+----------------+
| day | bg=1,1,1 | roundrobin |
+-----------------+----------------+----------------+
| noon | bg=0.5,0.5,0.5 | roundrobin |
+-----------------+----------------+----------------+
| night | bg=0,0,0&foo=2 | roundrobin |
+-----------------+----------------+----------------+
Table 4
| when a user clicks an object with the custom properties above, it
| should trigger either day noon or night in roundrobin fashion.
4.4. Usecase: click object or URI fragment, and scene load trigger
+=================+================+======================+
| custom property | value | trigger when |
+=================+================+======================+
| # | random | scene loaded |
+-----------------+----------------+----------------------+
| #random | random | URL contains #random |
+-----------------+----------------+----------------------+
| !random | day|noon|night | #random, # or click |
+-----------------+----------------+----------------------+
| day | bg=1,1,1 | roundrobin |
+-----------------+----------------+----------------------+
| noon | bg=0.5,0.5,0.5 | roundrobin |
+-----------------+----------------+----------------------+
| night | bg=0,0,0&foo=2 | roundrobin |
+-----------------+----------------+----------------------+
Table 5
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4.5. Usecase: present context menu with options
+=================+================+========================+
| custom property | value | trigger when |
+=================+================+========================+
| !random | !day | !noon |
+-----------------+----------------+------------------------+
| !day | bg=1,1,1 | clicked in contextmenu |
+-----------------+----------------+------------------------+
| !noon | bg=0.5,0.5,0.5 | clicked in contextmenu |
+-----------------+----------------+------------------------+
| !night | bg=0,0,0&foo=2 | clicked in contextmenu |
+-----------------+----------------+------------------------+
Table 6
| When interacting with an object with more than one !-macro, the XR
| Browser should offer a contextmenu to execute a macro.
In a similar way, when *any* !-macro is present on the sceneroot, the
XR Browser should offer a context-menu to execute those macro's.
4.6. Event Bubble-flow
click object with (!clickme:AR or !clickme: !reset e.g.)
└── does current object contain this property-key (`AR` or `!reset` e.g.)?
└── no: is there any (root)object containing property `AR`
└── yes: evaluate its (roundrobin) XR macro-value(s) (and exit)
└── no: trigger URL: #AR
click object with (!clickme:#AR|#VR e.g.)
└── apply the roundrobin (rotate the options, value `#AR` becomes `#VR` upon next click)
└── is there any object with property-key (`#AR` e.g.)?
└── no: just update the URL to `#AR`
└── yes: apply its value to the scene, and update the URL to `#AR`
click object with (`!clickme`:`!foo|!bar|!flop` e.g.)
◻ │
└── apply the roundrobin (rotate the options, value !foo becomes !bar
upon next click) └── is there any object with property-key (!foo
e.g.)? └── no: do nothing └── yes: apply its value to the scene ```
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| Note that only macro's can trigger roundrobin values or
| contextmenu's, as well as roundrobin values never ending up in the
| toplevel URL.
5. Security Considerations
6. IANA Considerations
This document has no IANA actions.
7. Acknowledgments
* NLNET (https://nlnet.nl)
* Future of Text (https://futureoftext.org)
* visual-meta.info (https://visual-meta.info)
8. Appendix: Definitions
+===============+===================================================+
| definition | explanation |
+===============+===================================================+
| scene | a (local/remote) 3D scene or 3D file |
| | (index.gltf e.g.) |
+---------------+---------------------------------------------------+
| 3D object | an object inside a scene characterized by |
| | vertex-, face- and customproperty data. |
+---------------+---------------------------------------------------+
| XR fragments | URI Fragment with spatial hints like |
| | #pos=0,0,0&t=1,100 e.g. |
+---------------+---------------------------------------------------+
| query | an URI Fragment-operator which queries |
| | object(s) from a scene like #q=cube |
+---------------+---------------------------------------------------+
| FPS | frames per second in spatial experiences |
| | (games,VR,AR e.g.), should be as high as |
| | possible |
+---------------+---------------------------------------------------+
| ◻ | ascii representation of an 3D object/mesh |
+---------------+---------------------------------------------------+
| (un)obtrusive | obtrusive: wrapping human text/thought in |
| | XML/HTML/JSON obfuscates human text into |
| | a salad of machine-symbols and words |
+---------------+---------------------------------------------------+
Table 7
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doc/RFC_XR_Macros.xml Normal file
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<?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-XRMACROS-leonvankammen-00" submissionType="IETF" category="info" xml:lang="en" xmlns:xi="http://www.w3.org/2001/XInclude" indexInclude="true" consensus="true">
<front>
<title>XR Macros</title><seriesInfo value="draft-XRMACROS-leonvankammen-00" stream="IETF" status="informational" name="XR-Macros"></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>Internet Engineering Task Force</workgroup>
<abstract>
<t>This draft offers a specification for embedding macros in existing 3D scenes/assets, to offer simple interactions and configure the renderer further.<br />
Together with URI Fragments, it allows for rich immersive experiences without the need of a complicated sandboxed scripting languages.</t>
<t>Almost every idea in this document is demonstrated at <eref target="https://xrfragment.org">https://xrfragment.org</eref>, as this spec was created during the <eref target="https://xrfragment.org">XR Fragments</eref> spec.</t>
</abstract>
</front>
<middle>
<section anchor="introduction"><name>Introduction</name>
<t>How can we add more features to existing text &amp; 3D scenes, without introducing new dataformats?<br />
Historically, there's many attempts to create the ultimate markuplanguage or 3D fileformat.<br />
Their lowest common denominator is: (co)authoring using plain text.<br />
Therefore, XR Macros allows us to enrich/connect existing dataformats, by offering a polyglot notation based on existing notations:<br />
</t>
<ol spacing="compact">
<li>getting/setting common used 3D properties using querystring- or JSON-notation</li>
<li>targeting 3D properties using the lightweight query notation present in <eref target="https://xrfragment.org">XR Fragments</eref></li>
</ol>
<blockquote><t>NOTE: The chapters in this document are ordered from highlevel to lowlevel (technical) as much as possible</t>
</blockquote></section>
<section anchor="core-principle"><name>Core principle</name>
<ol spacing="compact">
<li>XR Macros use querystrings, but are HTML-agnostic (though pseudo-XR Fragment browsers <strong>can</strong> be implemented on top of HTML/Javascript).</li>
<li>An XR Macro is 3D metadata which starts with '!' (<tt>!clickme: fog=0,10</tt> e.g.)</li>
<li>Metadata-values can contain the <tt>|</tt> symbol to 🎲 roundrobin variable values (<tt>!toggleme: fog=0,10|fog=0,1000</tt> e.g.)</li>
<li>XR Macros acts as simple eventhandlers for URI Fragments: they are automatically published on the (<eref target="https://xrfragment.org">XR Fragments</eref>) hashbus, to act as events (so more serious scripting languages can react to them as well).</li>
<li>XR Macros can assign object metadata (<tt>!setlocal: foo=1</tt> writes <tt>foo:1</tt> metadata to the object containing the <tt>!setlocal</tt> metadata)</li>
<li>XR Macros can assign global metadata (<tt>!setfoo: #foo=1</tt> writes <tt>foo:1</tt> metadata to the root scene-node)</li>
</ol>
<blockquote><t>These very simple principles allow for rich interactions and dynamic querying</t>
</blockquote></section>
<section anchor="conventions-and-definitions"><name>Conventions and Definitions</name>
<t>See appendix below in case certain terms are not clear.</t>
</section>
<section anchor="list-of-xr-macros"><name>List of XR Macros</name>
<t>(XR) Macros can be embedded in 3D assets/scenes.<br />
Macros enrich existing spatial content with a lowcode, limited logic-layer, by recursive (economic) use of the querystring syntax (which search engines and <eref target="https://xrfragment.org">XR Fragments</eref> already uses.<br />
This is done by allowing string/integer variables, and the <tt>|</tt> symbol to roundrobin variable values.<br />
Macros also act as events, so more serious scripting languages can react to them as well.<br />
</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>@bg</tt></td>
<td>string</td>
<td><tt>&quot;@bg&quot;:&quot;#cube&quot;</tt></td>
<td>bg: binds fog near/far based to cube x/y/z (anim) values</td>
<td>custom property in 3D fileformats</td>
</tr>
<tr>
<td><tt>@fog</tt></td>
<td>string</td>
<td><tt>&quot;@fog&quot;:&quot;#cube&quot;</tt></td>
<td>fog: binds fog near/far based to cube x/y (anim) values</td>
<td>custom property in 3D fileformats</td>
</tr>
<tr>
<td><tt>@scroll</tt></td>
<td>string</td>
<td><tt>&quot;@scroll&quot;:&quot;#cube&quot;</tt></td>
<td>texturescrolling: binds texture x/y/rot based to cube x/y/z (anim) values</td>
<td>custom property in 3D fileformats</td>
</tr>
<tr>
<td><tt>@emissive</tt></td>
<td>string</td>
<td><tt>&quot;@emissive&quot;:&quot;#cube&quot;</tt></td>
<td>day/night/mood: binds material's emissive value to cube x/y/z (anim) values</td>
<td>custom property in 3D fileformats</td>
</tr>
</tbody>
</table>
<section anchor="usecase-click-object"><name>Usecase: click object</name>
<table>
<thead>
<tr>
<th>custom property</th>
<th>value</th>
<th>trigger when</th>
</tr>
</thead>
<tbody>
<tr>
<td>!clickme</td>
<td>bg=1,1,1&amp;foo=2</td>
<td>object clicked</td>
</tr>
</tbody>
</table></section>
<section anchor="usecase-conditional-click-object"><name>Usecase: conditional click object</name>
<table>
<thead>
<tr>
<th>custom property</th>
<th>value</th>
<th>trigger when</th>
</tr>
</thead>
<tbody>
<tr>
<td>#</td>
<td>foo=1</td>
<td>scene</td>
</tr>
<tr>
<td>!clickme</td>
<td>q=foo&gt;2&amp;bg=1,1,1</td>
<td>object clicked and foo &gt; 2</td>
</tr>
</tbody>
</table><blockquote><t>when a user clicks an object with the custom properties above, it should set the backgroundcolor to <tt>1,1,1</tt> when <tt>foo</tt> is greater than <tt>2</tt> (see previous example)</t>
</blockquote></section>
<section anchor="usecase-click-object-roundrobin"><name>Usecase: click object (roundrobin)</name>
<table>
<thead>
<tr>
<th>custom property</th>
<th>value</th>
<th>trigger when</th>
</tr>
</thead>
<tbody>
<tr>
<td>!cycleme</td>
<td>day|noon|night</td>
<td>object clicked</td>
</tr>
<tr>
<td>day</td>
<td>bg=1,1,1</td>
<td>roundrobin</td>
</tr>
<tr>
<td>noon</td>
<td>bg=0.5,0.5,0.5</td>
<td>roundrobin</td>
</tr>
<tr>
<td>night</td>
<td>bg=0,0,0&amp;foo=2</td>
<td>roundrobin</td>
</tr>
</tbody>
</table><blockquote><t>when a user clicks an object with the custom properties above, it should trigger either <tt>day</tt> <tt>noon</tt> or <tt>night</tt> in roundrobin fashion.</t>
</blockquote></section>
<section anchor="usecase-click-object-or-uri-fragment-and-scene-load-trigger"><name>Usecase: click object or URI fragment, and scene load trigger</name>
<table>
<thead>
<tr>
<th>custom property</th>
<th>value</th>
<th>trigger when</th>
</tr>
</thead>
<tbody>
<tr>
<td>#</td>
<td>random</td>
<td>scene loaded</td>
</tr>
<tr>
<td>#random</td>
<td>random</td>
<td>URL contains #random</td>
</tr>
<tr>
<td>!random</td>
<td>day|noon|night</td>
<td>#random, # or click</td>
</tr>
<tr>
<td>day</td>
<td>bg=1,1,1</td>
<td>roundrobin</td>
</tr>
<tr>
<td>noon</td>
<td>bg=0.5,0.5,0.5</td>
<td>roundrobin</td>
</tr>
<tr>
<td>night</td>
<td>bg=0,0,0&amp;foo=2</td>
<td>roundrobin</td>
</tr>
</tbody>
</table></section>
<section anchor="usecase-present-context-menu-with-options"><name>Usecase: present context menu with options</name>
<table>
<thead>
<tr>
<th>custom property</th>
<th>value</th>
<th>trigger when</th>
</tr>
</thead>
<tbody>
<tr>
<td>!random</td>
<td>!day</td>
<td>!noon</td>
</tr>
<tr>
<td>!day</td>
<td>bg=1,1,1</td>
<td>clicked in contextmenu</td>
</tr>
<tr>
<td>!noon</td>
<td>bg=0.5,0.5,0.5</td>
<td>clicked in contextmenu</td>
</tr>
<tr>
<td>!night</td>
<td>bg=0,0,0&amp;foo=2</td>
<td>clicked in contextmenu</td>
</tr>
</tbody>
</table><blockquote><t>When interacting with an object with more than one <tt>!</tt>-macro, the XR Browser should offer a contextmenu to execute a macro.</t>
</blockquote><t>In a similar way, when <strong>any</strong> <tt>!</tt>-macro is present on the sceneroot, the XR Browser should offer a context-menu to execute those macro's.</t>
</section>
<section anchor="event-bubble-flow"><name>Event Bubble-flow</name>
<t>click object with (<tt>!clickme</tt>:<tt>AR</tt> or <tt>!clickme</tt>: <tt>!reset</tt> e.g.)</t>
<artwork><![CDATA[ ◻
└── does current object contain this property-key (`AR` or `!reset` e.g.)?
└── no: is there any (root)object containing property `AR`
└── yes: evaluate its (roundrobin) XR macro-value(s) (and exit)
└── no: trigger URL: #AR
]]>
</artwork>
<t>click object with (<tt>!clickme</tt>:<tt>#AR|#VR</tt> e.g.)</t>
<artwork><![CDATA[ ◻
└── apply the roundrobin (rotate the options, value `#AR` becomes `#VR` upon next click)
└── is there any object with property-key (`#AR` e.g.)?
└── no: just update the URL to `#AR`
└── yes: apply its value to the scene, and update the URL to `#AR`
click object with (`!clickme`:`!foo|!bar|!flop` e.g.)
]]>
</artwork>
<t>
<br />
└── apply the roundrobin (rotate the options, value <tt>!foo</tt> becomes <tt>!bar</tt> upon next click)
└── is there any object with property-key (<tt>!foo</tt> e.g.)?
└── no: do nothing
└── yes: apply its value to the scene
```</t>
<blockquote><t>Note that only macro's can trigger roundrobin values or contextmenu's, as well as roundrobin values never ending up in the toplevel URL.</t>
</blockquote></section>
</section>
<section anchor="security-considerations"><name>Security Considerations</name>
</section>
<section anchor="iana-considerations"><name>IANA Considerations</name>
<t>This document has no IANA actions.</t>
</section>
<section anchor="acknowledgments"><name>Acknowledgments</name>
<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>
</ul>
</section>
<section anchor="appendix-definitions"><name>Appendix: Definitions</name>
<table>
<thead>
<tr>
<th>definition</th>
<th>explanation</th>
</tr>
</thead>
<tbody>
<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>XR fragments</td>
<td>URI Fragment with spatial hints like <tt>#pos=0,0,0&amp;t=1,100</tt> e.g.</td>
</tr>
<tr>
<td>query</td>
<td>an URI Fragment-operator which queries object(s) from a scene like <tt>#q=cube</tt></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><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>
</tbody>
</table></section>
</middle>
</rfc>

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doc/fragments.awk Normal file
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BEGIN{
ROUNDROBIN="🎲"
ASSET="🔒"
OVERRIDE="🔓"
PV_OVERRIDE="💥"
NAVIGATOR="👩"
PROMPT="✋?"
EMBEDDED="🔗"
print "| fragment | type | access | scope |"
print "|----------|------|--------------|-------|"
}
END{
print ""
print ASSET" = value(s) can only defined in 3D asset (immutable)<br>"
print OVERRIDE" = value(s) can be overwritten in certain context<br>"
print ROUNDROBIN" = multiple values will be roundrobin'ed (`#pos=0,0,0|1,0,0` e.g.)<br>"
print PV_OVERRIDE" = value(s) can be overwritten by [predefined_view](#predefined_view)<br>"
print NAVIGATOR" = value(s) can be overwritten when user clicks `href` (value) or top-level URL change(see [How it works](#How%20it%20works))<br>"
print EMBEDDED" = value(s) can be overwritten when 3D asset is embedded/linked as `src` value<br>"
print PROMPT" = value(s) can be overwritten by offering confirmation/undo to user<br><br>"
print ""
print "for more info see [How it works](#How%20it%20works)"
}
/category:/ {
$1=$2=""
sub(/^[[:space:]]+/, "", $0 ) # remove leading spaces
sub(/[[:space:]]+$/, "", $0 ) # remove trailing spaces
scope=$0
}
/Frag.*XRF\.*/ {
gsub(/.*\("/,"",$1)
gsub(/".*/,"",$1)
type="string"
perms = $0 ~ /OVERRIDE/ ? OVERRIDE : ASSET
frag=$1
$1=""
if( $0 ~ /T_INT/ ) type="int"
if( $0 ~ /T_STRING_OBJ/ ) type="[string object](string object ) "
if( $0 ~ /T_VECTOR2/ ) type="[vector2](#vector ) "
if( $0 ~ /T_VECTOR3/ ) type="[vector3](#vector ) "
if( $0 ~ /T_URL/ ) type="[url](#url ) "
if( $0 ~ /T_PREDEFINED_VIEW/ ) type="[predefined view](#predefined_view ) "
if( $0 ~ /ROUNDROBIN/ ) perms=perms" "ROUNDROBIN
if( $0 ~ /PV_OVERRIDE/ ) perms=perms" "PV_OVERRIDE
if( $0 ~ /NAVIGATOR/ ) perms=perms" "NAVIGATOR
if( $0 ~ /EMBEDDED/ ) perms=perms" "EMBEDDED
if( $0 ~ /PROMPT/ ) perms=perms" "PROMPT
print "| **"frag"** |" type "|" perms "|" scope "|"
}

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# a no-nonsense source-to-markdown generator which scans for:
#
# /**
# * # foo
# *
# * this is markdown $(cat bar.md)
# */
#
# var foo; // comment with 2 leading spaces is markdown too $(date)
#
# easily refactorable to hash-based languages (py/bash/perl/lua e.g.)
# by changing the regexes
#
/\$\(/ { cmd=$0;
gsub(/^.*\$\(/,"",cmd);
gsub(/\).*/,"",cmd);
cmd | getline stdout; close(cmd);
sub(/\$\(.*\)/,stdout);
}
/\/\*\*/ { doc=1; sub(/^.*\/\*/,""); }
doc && /\*\// { doc=0;
sub(/[[:space:]]*\*\/.*/,"");
sub(/^[[:space:]]*\*[[:space:]]?/,"");
print
}
doc && /^[[:space:]]*\*/ { sub(/^[[:space:]]*\*[[:space:]]?/,"");
print
}
!doc && /\/\/ / { sub(".*// ","");
sub("# ","\n# ");
sub("> ","\n> ");
print
}

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#!/bin/sh
set -e
for topic in Fragments Macros; do
mmark RFC_XR_$topic.md > RFC_XR_$topic.xml
mmark --html RFC_XR_$topic.md | grep -vE '(<!--{|}-->)' > RFC_XR_$topic.html
xml2rfc --v3 RFC_XR_$topic.xml # RFC_XR_$topic.txt
sed -i 's/Expires: .*//g' RFC_XR_$topic.txt
convert -size 700x2400 xc:white -font "FreeMono" +antialias -pointsize 12 -fill black -annotate +15+15 "@RFC_XR_Fragments.txt" -colorspace gray +dither -posterize 6 RF6_XR_Fragments.png
done

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\#static allow client to ignore lower-prio objects in the renderloop, to compensate frame-drop/cpu/gpu-overload scenarios
Q: should `-` be used to indicate 'lowering' priority (css's `z-index` 0-??? range is a bit confusing in that sense)

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{ pkgs ? import <nixos-unstable> {} } :
{
pkgs = import (builtins.fetchGit {
name = "nixos-23.05";
url = "https://github.com/nixos/nixpkgs/";
ref = "refs/heads/nixos-unstable";
rev = "ef99fa5c5ed624460217c31ac4271cfb5cb2502c";
});
foo = pkgs.mkShell {
# nativeBuildInputs is usually what you want -- tools you need to run
nativeBuildInputs = with pkgs.buildPackages; [
mmark
xml2rfc
python312Packages.lxml
wkhtmltopdf-bin
imagemagick
];
};
# to create [markdown] table of contents use LLM with this input: awk '/id="/ { print $0 }' RFC_XR_Fragments.html | grep -v idx
}

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:root {
--color-a: black;
--color-at: #000000CC;
--color-b: #222;
--color-c: #444;
--color-d: #888;
--color-e: #FF0;
--color-f: #CCC;
--color-g: #FFF;
--color-gt: #FFF5;
--params-width: 320px;
--font-1: 'Montserrat', sans-serif;
--font-2: monospace, courier;
--font-size-1: 57px;
--font-size-2: 26px;
--font-size-3: 18px;
--font-size-4: 15px;
--gutter-1: 10%;
--gradient-1: linear-gradient(45deg, #dc2454 0%, #944a9d 51%, #4824dc 100%);
--gradient-2: linear-gradient(45deg, #dc2454 0%, #944a9d 21%, #4824dc 50%,#dc2454 70%, #944a9d 88%, #4824dc 100%);
}
body>h1:nth-child(1) {
display:none;
}
body{
position:relative;
width:100%;
height:100vh;
color: var(--color-d);
line-height: 38px;
margin:0;
padding:0;
font-size: var(--font-size-3);
}
* {
font-family: var(--font-1);
font-size: var(--font-size-3);
font-weight:500;
color: var(--color-c);
}
img,
.img{
image-rendering: -webkit-optimize-contrast;
}
#jumbotron{
margin-top:50px;
}
b{
font-weight: 700;
}
h1 {
color: var(--color-c);
font-size: var(--font-size-1);
font-weight:700;
margin: 0;
line-height: 11vh;
padding-right:40px;
}
h2 {
font-size: var(--font-size-2);
font-weight:400;
padding-right:40px;
}
h3 {
background-image: var(--gradient-1);
color: var(--color-g);
display:inline;
border-radius: 5px;
padding: 2px 10px 2px 10px;
font-weight: 600;
font-size: var(--font-size-4);
text-transform:uppercase;
white-space:nowrap;
}
@media only screen and (max-width: 700px) {
body {
font-size: var(--font-size-3);
line-height: 40px;
}
svg.img{
transform: scale(0.8);
}
.content{
padding-top: 60px;
margin-left: 27px !important;
padding-right: 54px !important;
}
.heading{
transform:scale(0.7);
}
}
table {
border:none;
box-shadow: 0px 0px 10px #0005;
padding:20px;
background: transparent !important;
border-radius:4px;
}
table tr td,
table tr th {
vertical-align:top;
text-align:left;
border-bottom:1px solid #555;
color: var(--color-d);
}
table tr td a:visited,
table tr td a:active,
table tr td a{
color: var(--color-e);
}
table tr:last-child td{
border:none;
}
table tr th {
border-bottom:2px solid var(--color-d);
}
code{
display: inline-block;
unicode-bidi: embed;
font-family: monospace;
white-space: pre;
background: var(--color-c);
margin-bottom: 5px;
padding: 0px 5px;
font-size:16px;
}
.content {
height:99vh;
max-width: 50em;
width: 100%;
margin: 0 auto;
padding-top:25px;
box-sizing:border-box;
}
a,a:visited,a:active{
color: var(--color-a);
display:inline-block;
text-decoration:none;
}
a:hover{
opacity:0.9;
}
/* lato-regular - latin */
@font-face {
font-family: 'Lato';
font-style: normal;
font-weight: 400;
src: url('/assets/font/lato-v17-latin-regular.eot'); /* IE9 Compat Modes */
src: local(''),
url('/assets/font/lato-v17-latin-regular.eot?#iefix') format('embedded-opentype'), /* IE6-IE8 */
url('/assets/font/lato-v17-latin-regular.woff2') format('woff2'), /* Super Modern Browsers */
url('/assets/font/lato-v17-latin-regular.woff') format('woff'), /* Modern Browsers */
url('/assets/font/lato-v17-latin-regular.ttf') format('truetype'), /* Safari, Android, iOS */
url('/assets/font/lato-v17-latin-regular.svg#Lato') format('svg'); /* Legacy iOS */
}
#sidemenu {
position:absolute;
top:0;
left:0;
}
#sidemenu nav {
width: 300px;
box-shadow: 0px 0px 8px #0005;
background:#FFF;
z-index:10;
position: fixed;
top: 0;
left: 0;
z-index: 99;
height:100vh;
}
#sidemenu .sidemenu__btn {
display: block;
width: 50px;
height: 50px;
top:20px;
left:20px;
background: transparent;
border: none;
position: fixed;
z-index: 100;
-webkit-appearance: none;
-moz-appearance: none;
appearance: none;
cursor: pointer;
outline: none;
}
#sidemenu .sidemenu__btn span {
display: block;
width: 30px;
height: 3px;
margin: auto;
background:var(--color-d);
position: absolute;
top: 0;
bottom: 0;
left: 0;
right: 0;
-webkit-transition: all .4s ease;
transition: all .4s ease;
}
#sidemenu .sidemenu__btn span.top {
-webkit-transform: translateY(-8px);
transform: translateY(-8px);
}
#sidemenu .sidemenu__btn span.bottom {
-webkit-transform: translateY(8px);
transform: translateY(8px);
}
#sidemenu .sidemenu__btn.active .top {
-webkit-transform: rotate(-45deg);
transform: rotate(-45deg);
}
#sidemenu .sidemenu__btn.active .mid {
-webkit-transform: translateX(-20px) rotate(360deg);
transform: translateX(-20px) rotate(360deg);
opacity: 0;
}
#sidemenu .sidemenu__btn.active .bottom {
-webkit-transform: rotate(45deg);
transform: rotate(45deg);
}
#sidemenu .sidemenu__wrapper {
padding-top: 70px;
margin-left:20px;
}
#sidemenu .sidemenu__list {
overflow-y: scroll;
max-height: 73vh;
padding-top: 50px;
list-style: none;
padding: 0;
margin: 0;
}
#sidemenu .sidemenu__item {
padding: 0;
}
#sidemenu li > a {
text-decoration: none;
display: inline-block;
-webkit-transition: .4s ease;
transition: .4s ease;
cursor: pointer;
}
nav {
-webkit-transition: .2s ease;
transition: .2s ease;
-webkit-transform: translateX(0px);
transform: translateX(0px);
opacity:1;
}
nav.hide {
-webkit-transform: translateX(-300px);
transform: translateX(-300px);
opacity:0;
}
ul, ol {
margin-left:30px !important;
margin-top: 35px !important;
margin-bottom: 35px !important;
}
ul:nth-child(1){
margin:0;
}
ul,li{
text-decoration:none !important;
/*list-style:none;*/
padding-left:10px;
padding-right:10px;
}
li > a,
li > a.visited,
li > a.active{
color:#555;
padding:5px;
}
li > b {
background:#FFF;
padding:5px;
}
.sidemenu__list > li,
.sidemenu__list > ul > li{
display:inline-block;
}
ul > li {
display:block;
}
.content ul > li::before {content: "•"; padding-right:10px;color: #54F;}
li > b {
font-weight:100;
}
.touchscreen {
border:30px solid #aab5bb;
border-radius:20px;
position:relative;
}
.touchscreen:after {
content:"";
display:block;
position:absolute;
border-radius:50%;
width:15px;
height:15px;
background:#FFF;
top:136px;
right:-22px;
}
div.pretty{
border-radius: 4px;
display: block;
background: #372e42;
overflow-x: scroll;
white-space:pre-wrap;
color:#65e;
}
code.pretty,
div.pretty > pre > code{
background: -webkit-linear-gradient(-70deg,#98a7f0,#0d4e50);
background-clip: border-box;
-webkit-background-clip: text;
-webkit-text-fill-color: transparent;
border: none;
text-shadow: 0px 0px 5px #fff9;
filter: brightness(1.8);
font-size:14px;
width:98%;
padding:0px 15px;
margin:0;
box-sizing:border-box;
line-height:20px;
}
blockquote{
box-sizing: border-box;
background: transparent !important;
border-radius: 7px;
padding: 20px;
width: 100%;
margin: 30px 0px 20px 0px;
color: var(--color-f) !important;
font-weight: bold;
}
blockquote a {
color:#000 !important;
}
blockquote a:hover {
color:#FFF !important;
background:#000;
}
img {
width:100%;
filter: brightness(0.97)
}
/* GRID SYSTEM */
.block{
display: block;
text-align: left;
margin-bottom: var(--gutter-1);
min-height:55vh;
}
.block .img{
border-radius:15px;
width:100%;
height:35vh;
margin-bottom:15px;
background-size: cover;
}
p{ margin:0; padding:0; }
//the grid:
.grid{
width: 90%;
max-width: 900px;
margin: 0 auto;
background-color: $grid-color;
//just for styling:
padding-top: var(--gutter-1);
}
.gutter{
/*
margin-left: calc( var(--gutter-1) /2 );
margin-right: calc( var(--gutter-1) /2 );
*/
margin-right: var(--gutter-1);
}
.col-33{
width: 33.3%;
float: left;
}
.col-50{
width: 50%;
float: left;
}
.clear{
clear: both;
display: block;
}
//responsive
@media all and (max-width:800px) {
.col-33{
width: 50%;
}
}
@media all and (max-width:600px) {
.col-50, .col-33{
width: 100%;
float: none;
}
h1 {
font-size: 50px;
line-height:70px;
}
h2{
font-size: var(--font-size-3);
}
.block.gutter{
margin-right:0;
}
}
.darken{
filter: brightness(0.8);
}
button{
cursor:pointer;
padding: 10px;
border-radius: 6px;
background-image: var(--gradient-1);
border: none;
border-radius: 20px;
display:inline-block;
color: #FFF;
border: none;
opacity:1.0;
font-size: var(--font-size-4);
font-weight:600;
}
button:hover{
opacity:0.8;
}
.gradient{
background-image: var(--gradient-2);
-webkit-background-clip: text;
-webkit-text-fill-color: transparent;
}

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