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

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).
2. An XR Macro is 3D metadata which starts with ‘!’ (!clickme: fog=0,10 e.g.)
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) 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

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.
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 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.

Usecase: click object

Usecase: conditional click object

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)

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

Usecase: present context menu with options

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
• Future of Text
• visual-meta.info

Appendix: Definitions