[x3d-public] Immersive Web Device API Specification

Wed Feb 6 06:02:09 PST 2019

AR - after skim reading the webXR AR blog, a few questions and thoughts
popped to mind:
-Doug Sanden

1) when asking for the next frame, will the frame already be appropriately
cleared and backfilled?
- some AR may need a transparent background
- some AR may have a front facing camera, and fill the background with that
2) for Hit Test how complicated can we get?
a) simple hit test: take the head height aka 'level' from the pose, and
project a ray and where it intersects horizontal 1.7m below current pose,
that's the floor
b) more complex: if there's a machine vision system that can recognize
objects, then
-- a declarative list of objects to look for, and when found, judge their
distance for hit testing
-- a declarative list of horizontal surfaces to recognize, by height
-- and hit test would include those objects
c) more complex: if there's a machine vision system or laser range finder
that can find all surfaces along the hit ray, then return that distance,
even if there's no recognizable object ie generic terrain, for avoidance
and placing virtual objects

On Tue, Feb 5, 2019 at 10:25 PM Leonard Daly <Leonard.Daly at realism.com>
wrote:

> Andreas,
>
> This version (V1.0) of the device API does not attempt to address
> augmented reality (where a portion of the displayed scene is provided by
> the "real world"). That will be address in V1.1 (planned for Summer 2020).
> This version is strictly for virtual reality where the entire scene is
> computer generated. It is difficult to use at the moment because it
> requires support from the browser environment. It might be possible to
> extend the WebVR polyfill to support this API for much (but probably not
> all) features.
>
> There is an issue in the Immersive Web Community Group to address
> declarative languages. The issue was recently opened and is accepting
> comments.
>
> This may be a time for X3D to really clarify how it is going to fit into
> the web eco-system by answering the questions:
>
>    - Does X3D handle AR content/scenes?
>    - If not, where in XR spectrum does X3D apply?
>    - Will X3D be compliant with the Immersive Web specification?
>       - If so, what has to change in X3D?
>       - What will happen when X3D is used in a non-browser environment?
>          - If not, in what environments will X3D operate?
>       - How does the SAI need to change? (If X3D is not going to be IW
>       spec compliant, there may be no changes necessary.)
>       - What happens to non-ECMAScript/JavaScript language bindings?
>
> This article that Andreas links below describes what is necessary to test
> WebXR in Chrome. You will need to sign up.
>
> Leonard Daly
>
>
> Thanks, good to see. I found this summary helpful as well.
> https://developers.google.com/web/updates/2018/05/welcome-to-immersive
>
> WebXR is actually available now, but web developers have to request a
> revocable permission token to use the API with Chrome.
>
> Easiest to use for experimentation is a polyfill using the now
> superceded WebVR API. I feel only actually trying to use it will be
> able to discover issues.
>
> I see Layers are still there. In WebVR they were never supported, I think.
>
> X3D was not designed for AR (or perhaps it was ?) but the SAI would
> provides a way to feed in the real world into a Scene, using a
> backend.
>
> There just does not seem be to a declarative interface to the real
> world, if that even would make sense.
>
> How do you best/declaratively provide a floor or a tracked table as
> recognized by a smart camera to a X3D scene which then lets you
> interact (see how a new couch would fit) ?
>
> -Andreas
>
> On Tue, Feb 5, 2019 at 3:25 PM <x3d-public-request at web3d.org> <x3d-public-request at web3d.org> wrote:
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>    1. Immersive Web Device API Specification (Leonard Daly)
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> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 5 Feb 2019 08:49:38 -0800
> From: Leonard Daly <Leonard.Daly at realism.com> <Leonard.Daly at realism.com>
> To: X3D Public <x3d-public at web3d.org> <x3d-public at web3d.org>
> Subject: [x3d-public] Immersive Web Device API Specification
> Message-ID: <6f0e735b-21f6-748f-9bf6-14f3ebee247f at realism.com> <6f0e735b-21f6-748f-9bf6-14f3ebee247f at realism.com>
> Content-Type: text/plain; charset="utf-8"; Format="flowed"
>
> The W3C has just published the first public WORKING DRAFT of the WebXR
> Device API (https://www.w3.org/TR/2019/WD-webxr-20190205/). This is not
> intended to be a fully fleshed out specification, but an early draft to
> elicit comments from the public.
>
> The API is the interface expressed in JavaScript between the user code
> and the browser that controls much of the WebXR device functionality or
> information. This includes things like setting up the session, handling
> device orientation data, etc. It does not include the rendering
> pipeline, and you still must call window.requestAnimationFrame for each
> change to the display.
>
> A very useful document is the WebXR Device API Explainer
> (https://github.com/w3c/webvr/blob/master/explainer.md). This document
> describes in non-spec language the philosophy behind the spec document
> and may include more information than the spec WD in areas that are not
> fully written.
>
> If you find an issue (or more than one) with the spec document you can
> report to the public-immersive-web at w3.org list (you need to be a member
> of the list (seehttps://lists.w3.org/Archives/Public/public-immersive-web/) or to any
> Immersive Web WG member
> (https://www.w3.org/2000/09/dbwg/details?group=109735&order=org&public=1).
> Of particular interest are
>
>  1. items that differ from the Explainer
>  2. items that cannot be done in JavaScript
>  3. items that are inconsistent within the WD specification
>  4. items that conflict with other W3C standards.
>
> --
> *Leonard Daly*
> 3D Systems & Cloud Consultant
> LA ACM SIGGRAPH Past Chair
> President, Daly Realism - /Creating the Future/
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> *Leonard Daly*
> 3D Systems & Cloud Consultant
> LA ACM SIGGRAPH Past Chair
> President, Daly Realism - *Creating the Future*
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