%%% Title = "XR Fragments" area = "Internet" workgroup = "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" %%% .# Abstract This draft is a specification for 4D URLs & navigation, which links together space, time & text together, for hypermedia browsers with- or without a network-connection.
The specification promotes spatial addressibility, sharing, navigation, query-ing and annotating interactive (text)objects across for (XR) Browsers.
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.
> 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?
Historically, there's many attempts to create the ultimate markuplanguage or 3D fileformat.
Their lowest common denominator is: (co)authoring using plain text.
XR Fragments allows us to enrich/connect existing dataformats, by recursive use of existing technologies:
1. addressibility and navigation of 3D scenes/objects: [URI Fragments](https://en.wikipedia.org/wiki/URI_fragment) + src/href spatial metadata 1. Interlinking text/& 3D by collapsing space into a Word Graph (XRWG) (and augmenting text with [bibs](https://github.com/coderofsalvation/tagbibs) / [BibTags](https://en.wikipedia.org/wiki/BibTeX) appendices (see [visual-meta](https://visual-meta.info) e.g.) 1. extend the hashtag-to-browser-viewport paradigm beyond 2D documents (XR documents) > 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.
This also means that the repair-ability of machine-matters should be human friendly too (not too complex).
XR Fragments tries to seek to connect the world of text (semantical web / RDF), and the world of pixels.
Instead of combining them (in a game-editor e.g.), XR Fragments is opting for a more integrated path **towards** them, by describing how to make browsers **4D URL-ready**: | principle | XR 4D URL | HTML 2D URL | |----------------------|----------------------------------------------|---------------------------------------| | the XRWG | wordgraph (collapses 3D scene to tags) | Ctrl-F (find) | | the hashbus | hashtags map to camera/scene-projections | hashtags map to document positions | | spacetime hashtags | positions camera, triggers scene-preset/time | jumps/scrolls to chapter | > XR Fragments does not look at XR (or the web) thru the lens of HTML.
But approaches things from a higherlevel browser-perspective: ``` +----------------------------------------------------------------------------------------------+ | | | the soul of any URL: ://macro /meso ?micro #nano | | | | 2D URL: ://library.com /document ?search #chapter | | | | 4D URL: ://park.com /4Dscene.fbx --> ?search --> #view ---> hashbus | | │ | | | XRWG <---------------------<------------+ | | │ | | | ├─ objects --------------->------------| | | └─ text --------------->------------+ | | | | | +----------------------------------------------------------------------------------------------+ ``` Traditional webbrowsers can become 4D document-ready by: * loading 3D assets (gltf/fbx e.g.) natively (not thru HTML). * allowing assets to publish hashtags to themselves (the scene) using the hashbus (like hashtags controlling the scrollbar). * collapsing the 3D scene to an wordgraph (for essential navigation purposes) controllable thru a hash(tag)bus XR Fragments itself is HTML-agnostic, though pseudo-XR Fragment browsers **can** be implemented on top of HTML/Javascript. # Conventions and Definitions See appendix below in case certain terms are not clear. ## 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 | > this is already implemented in all browsers # 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-or-tagname) | > 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 | | `tag` | string | `"tag": "cubes geo"` | available through custom property in 3D fileformats | | `href` | string | `"href": "b.gltf"` | available through custom property in 3D fileformats | | `src` | string | `"src": "#cube"` | available through custom property in 3D fileformats | Popular compatible 3D fileformats: `.gltf`, `.obj`, `.fbx`, `.usdz`, `.json` (THREE.js), `.dae` 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`.
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 `◻` with/out using queries: ``` +--------------------------------------------------------+ +-------------------------+ | | | | | index.gltf | | ocean.com/aquarium.fbx | | │ | | │ | | ├── ◻ canvas | | └── ◻ fishbowl | | │ └ src: painting.png | | ├─ ◻ bass | | │ | | └─ ◻ tuna | | ├── ◻ aquariumcube | | | | │ └ src: ://rescue.com/fish.gltf#bass%20tuna | +-------------------------+ | │ | | ├── ◻ bedroom | | │ └ src: #canvas | | │ | | └── ◻ livingroom | | └ src: #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).
Also, after lazy-loading `ocean.com/aquarium.gltf`, only the queried objects `bass` and `tuna` will be instanced inside `aquariumcube`.
Resizing will be happen accordingly to its placeholder object `aquariumcube`, see chapter Scaling.
> Instead of cherrypicking objects with `#bass&tuna` thru `src`, queries can be used to import the whole scene (and filter out certain objects). See next chapter below. # XR Fragment queries Include, exclude, hide/shows objects using space-separated strings: | example | outcome | |----------------------------------|------------------------------------------------------------------------------------| | `#q=-sky` | show everything except object named `sky` | | `#q=-.language .english` | hide everything with tag `language`, but show all tag `english` objects | | `#q=price:>2 price:<5` | of all objects with property `price`, show only objects with value between 2 and 5 | It's simple but powerful syntax which allows css-like tag/id-selectors with a searchengine prompt-style feeling: 1. queries are a way to traverse a scene, and filter objects based on their tag- or property-values. 1. words starting with `.` like `.german` match tag-metadata of 3D objects like `"tag":"german"` 1. words starting with `.` like `.german` match tag-metadata of (BibTeX) tags in XR Text objects like `@german{KarlHeinz, ...` e.g. > **For example**: `#q=.foo` is a shorthand for `#q=tag:foo`, which will select objects with custom property `tag`:`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 | |----------|-------------------------------------------------------------------------------------------------------------------------------| | `-` | removes/hides object(s) | | `:` | indicates an object-embedded custom property key/value | | `.` | alias for `"tag" :".foo"` equals `tag:foo` | | `>` `<` | compare float or int number | | `/` | reference to root-scene.
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)
`#q=-cube` hides both object `cube` in the root-scene AND 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 tag selectors like `.foo` (reference regex: `/^[-]?tag$/` ) 1. detect number values like `foo:1` (reference regex: `/^[0-9\.]+$/` ) 1. expand aliases like `.foo` into `tag: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) # Embedding local/remote content (instancing) `src` is the 3D version of the iframe.
It instances content (in objects) in the current scene/asset. | fragment | type | example value | |----------|------|---------------| |`src`| string (uri or [[predefined view|predefined_view]] or [[query|queries]]) | `#cube`
`#q=-ball_inside_cube`
`#q=-/sky -rain`
`#q=-.language .english`
`#q=price:>2 price:<5`
`https://linux.org/penguin.png`
`https://linux.world/distrowatch.gltf#t=1,100`
`linuxapp://conference/nixworkshop/apply.gltf#q=flyer`
`androidapp://page1?tutorial#pos=0,0,1&t1,100`| 1. local/remote content is instanced by the `src` (query) value (and attaches it to the placeholder mesh containing the `src` property) 1. local `src` values (URL **starting** with `#`, like `#cube&foo`) means **only** the mentioned objectnames will be copied to the instanced scene (from the current scene) while preserving their names (to support recursive selectors). [[(example code)|https://github.com/coderofsalvation/xrfragment/blob/main/src/3rd/js/three/xrf/src.js]] 1. local `src` values indicating a query (`#q=`), means that all included objects (from the current scene) will be copied to the instanced scene (before applying the query) while preserving their names (to support recursive selectors). [[(example code)|https://github.com/coderofsalvation/xrfragment/blob/main/src/3rd/js/three/xrf/src.js]] 1. the instanced scene (from a `src` value) should be scaled accordingly to its placeholder object or scaled relatively based on the scale-property (of a geometry-less placeholder, an 'empty'-object in blender e.g.). For more info see Chapter Scaling. 1. external `src` (file) values should be served with appropriate mimetype (so the XR Fragment-compatible browser will now how to render it). The bare minimum supported mimetypes are: 1. when only one object was cherrypicked (`#cube` e.g.), set its position to `0,0,0` * `model/gltf+json` * `image/png` * `image/jpg` * `text/plain;charset=utf-8;bib=^@` ## Scaling instanced content # Text in XR (tagging,linking to spatial objects) How does XR Fragments interlink text with objects? > The XR Fragments does this by collapsing space into a **Word Graph** (the **XRWG**), augmented by Bib(s)Tex. Instead of just throwing together all kinds media types into one experience (games), what about the intrinsic connections between them?
Why is HTML adopted less in games outside the browser? Through the lens of game-making, ideally metadata must come **with** that text, but not **obfuscate** the text, or **spawning another request** to fetch it.
XR Fragments does this by detecting Bib(s)Tex, without introducing a new language or fileformat
> Why Bib(s)Tex? Because its seems to be the lowest common denominator for an human-curated XRWG (extendable by speech/scanner/writing/typing e.g, see [further motivation here](https://github.com/coderofsalvation/hashtagbibs#bibs--bibtex-combo-lowest-common-denominator-for-linking-data)) Hence: 1. XR Fragments promotes (de)serializing a scene to the XRWG 2. XR Fragments primes the XRWG, by collecting words from the `tag` and name-property of 3D objects. 3. XR Fragments primes the XRWG, by collecting words from **optional** metadata **at the end of content** of text (see default mimetype & Data URI) 4. [Bib's](https://github.com/coderofsalvation/hashtagbibs) and BibTex are first tag citizens for priming the XRWG with words (from XR text) 5. Like Bibs, XR Fragments generalizes the BibTex author/title-semantics (`author{title}`) into **this** points to **that** (`this{that}`) 6. The XRWG should be recalculated when textvalues (in `src`) change 7. HTML/RDF/JSON is still great, but is beyond the XRWG-scope (they fit better in the application-layer) 8. Applications don't have to be able to access the XRWG programmatically, as they can easily generate one themselves by traversing the scene-nodes. 9. The XR Fragment focuses on fast and easy-to-generate end-user controllable word graphs (instead of complex implementations that try to defeat word ambiguity) Example: ``` http://y.io/z.fbx | Derived XRWG (shown as BibTex) ----------------------------------------------------------------------------+-------------------------------------- | @house{castle, +-[src: data:.....]----------------------+ +-[3D mesh]-+ | url = {https://y.io/z.fbx#castle} | Chapter one | | / \ | | } | | | / \ | | @baroque{castle, | John built houses in baroque style. | | / \ | | url = {https://y.io/z.fbx#castle} | | | |_____| | | } | #john@baroque | +-----│-----+ | @baroque{john} | | │ | | | ├─ name: castle | | | └─ tag: house baroque | +----------------------------------------+ | [3D mesh ] | | O ├─ name: john | | /|\ | | | / \ | | +--------+ | ``` > the `#john@baroque`-bib associates both text `John` and objectname `john`, with tag `baroque` ``` Another example: ``` http://y.io/z.fbx | Derived XRWG (printed as BibTex) ----------------------------------------------------------------------------+-------------------------------------- | +-[src: data:.....]----------------------+ +-[3D mesh]-+ | @house{castle, | Chapter one | | / \ | | url = {https://y.io/z.fbx#castle} | | | / \ | | } | John built houses in baroque style. | | / \ | | @baroque{castle, | | | |_____| | | url = {https://y.io/z.fbx#castle} | #john@baroque | +-----│-----+ | } | @baroque{john} | │ | @baroque{john} | | ├─ name: castle | | | └─ tag: house baroque | +----------------------------------------+ | @house{baroque} [3D mesh ] | @todo{baroque} +-[remotestorage.io / localstorage]------+ | O + name: john | | #baroque@todo@house | | /|\ | | | ... | | / \ | | +----------------------------------------+ +--------+ | ``` > both `#john@baroque`-bib and BibTex `@baroque{john}` result in the same XRWG, however on top of that 2 tages (`house` and `todo`) are now associated with text/objectname/tag 'baroque'. As seen above, the XRWG can expand [bibs](https://github.com/coderofsalvation/hashtagbibs) (and the whole scene) to BibTeX.
This allows hasslefree authoring and copy-paste of associations **for and by humans**, but also makes these URLs possible: | URL example | Result | |---------------------------------------|---------------------------------------------------------------------------| | `https://my.com/foo.gltf#.baroque` | highlights mesh `john`, 3D mesh `castle`, text `John built(..)` | | `https://my.com/foo.gltf#john` | highlights mesh `john`, and the text `John built (..)` | | `https://my.com/foo.gltf#house` | highlights mesh `castle`, and other objects with tag `house` or `todo` | > [hashtagbibs](https://github.com/coderofsalvation/hashtagbibs) potentially allow the enduser to annotate text/objects by **speaking/typing/scanning associations**, which the XR Browser saves to remotestorage (or localStorage per toplevel URL). As well as, referencing BibTags per URI later on: `https://y.io/z.fbx#@baroque@todo` e.g. The XRWG allows XR Browsers to show/hide relationships in realtime at various levels: * wordmatch **inside** `src` text * wordmatch **inside** `href` text * wordmatch object-names * wordmatch object-tagnames Spatial wires can be rendered, words/objects can be highlighted/scaled etc.
Some pointers for good UX (but not necessary to be XR Fragment compatible): 9. 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) 10. 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. 12. respect multi-line BiBTeX metadata in text because of [the core principle](#core-principle) 13. Default font (unless specified otherwise) is a modern monospace font, for maximized tabular expressiveness (see [the core principle](#core-principle)). 14. anti-pattern: hardcoupling an XR Browser with a mandatory **markup/scripting-language** which departs from onubtrusive plain text (HTML/VRML/Javascript) (see [the core principle](#core-principle)) 15. anti-pattern: limiting human introspection, by abandoning plain text as first tag citizen. > The simplicity of appending metadata (and leveling the metadata-playfield between humans and machines) is also demonstrated by [visual-meta](https://visual-meta.info) in greater detail. Fictional chat: ``` Hey what about this: https://my.com/station.gltf#pos=0,0,1&rot=90,2,0&t=500,1000 I'm checking it right now I don't see everything..where's our text from yesterday? Ah wait, that's tagged with tag 'draft' (and hidden)..hold on, try this: https://my.com/station.gltf#.draft&pos=0,0,1&rot=90,2,0&t=500,1000 how about we link the draft to the upcoming YELLO-event? ok I'm adding #draft@YELLO Yesterday I also came up with other usefull assocations between other texts in the scene: #event#YELLO #2025@YELLO thanks, added. Btw. I stumbled upon this spatial book which references station.gltf in some chapters: https://thecommunity.org/forum/foo/mytrainstory.txt interesting, I'm importing mytrainstory.txt into station.gltf ah yes, chapter three points to trainterminal_2A in the scene, cool ``` ## 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 * lines beginning with `@` will not be rendered verbatim by default ([read more](https://github.com/coderofsalvation/hashtagbibs#hashtagbib-mimetypes)) * the XRWG should expand bibs to BibTex occurring in text (`#contactjohn@todo@important` e.g.) By doing so, the XR Browser (applications-layer) can interpret microformats ([visual-meta](https://visual-meta.info) to connect text further with its environment ( setup links between textual/spatial objects automatically e.g.). > for more info on this mimetype see [bibs](https://github.com/coderofsalvation/hashtagbibs) Advantages: * auto-expanding of [hashtagbibs](https://github.com/coderofsalvation/hashtagbibs) associations * 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).
## URL and Data URI ``` +--------------------------------------------------------------+ +------------------------+ | | | author.com/article.txt | | index.gltf | +------------------------+ | │ | | | | ├── ◻ article_canvas | | Hello friends. | | │ └ src: ://author.com/article.txt | | | | │ | | @book{greatgatsby | | └── ◻ note_canvas | | ... | | └ src:`data:welcome human\n@book{sunday...}` | | } | | | +------------------------+ | | +--------------------------------------------------------------+ ``` The enduser will only see `welcome human` and `Hello friends` rendered verbatim (see mimetype). The beauty is that text in Data URI automatically promotes rich copy-paste (retaining metadata). 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` ## XR Text example parser To prime the XRWG with text from plain text `src`-values, here's an example XR Text (de)multiplexer in javascript (which supports inline bibs & bibtex): ``` 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}{${match},\n}` }) return text.replace( bibs.regex, '') + Object.values(bibs.tags).join('\n') }, decode: (str) => { // bibtex: ↓@ ↓ ↓property ↓end let pat = [ /@/, /^\S+[,{}]/, /},/, /}/ ] let tags = [], text='', i=0, prop='' let lines = xrtext.expandBibs(str).replace(/\r?\n/g,'\n').split(/\n/) for( let i = 0; i < lines.length && !String(lines[i]).match( /^@/ ); i++ ) text += lines[i]+'\n' bibtex = lines.join('\n').substr( text.length ) bibtex.split( pat[0] ).map( (t) => { try{ let v = {} if( !(t = t.trim()) ) return if( tag = t.match( pat[1] ) ) tag = tag[0] if( tag.match( /^{.*}$/ ) ) return tags.push({ruler:tag}) if( tag.match( /}$/ ) ) return tags.push({k: tag.replace(/}$/,''), v: {}}) 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 vice versa > 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} } ``` > when an XR browser updates the human text, a quick scan for nonmatching tags (`@book{nonmatchingbook` e.g.) should be performed and prompt the enduser for deleting them. # 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 `tag:secret` e.g.) # 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 | |----------------------|--------------------------------------------------------------------------------------------------------------------------------------| |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. | |the XRWG | wordgraph (collapses 3D scene to tags) | |the hashbus | hashtags map to camera/scene-projections | |spacetime hashtags | positions camera, triggers scene-preset/time | |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 | 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 | |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 |