[x3d-public] [x3d] V4.0 Open discussion/workshop on X3D HTML integration

Wed Jun 8 19:56:54 PDT 2016

Leonard, please review the HTML5 Recommendation again for answers to some of your issues.

1. Similar to X3D, HTML5 defines functionality in an abstract way before Two encodings are defined, in adjacent chapters: loose HTML syntax and strict XML/XHTML syntax.  Both are compatible because they have reconciled idiosyncrasies by aligning each with the DOM.  Indeed this dual nature appears in the title of the W3C Recommendation.

These links have been posted multiple times in the past:

	HTML5: A vocabulary and associated APIs for HTML and XHTML
	https://www.w3.org/TR/html5/

	8 The HTML syntax
	https://www.w3.org/TR/html5/syntax.html#syntax

	9 The XHTML syntax
	https://www.w3.org/TR/html5/the-xhtml-syntax.html#the-xhtml-syntax

Of note is that X3DOM itself works with both encodings.  Most of the Fraunhofer examples use HTML syntax.  Over 3000 Web3D examples use the XHTML syntax, where the XML is directly inserted into the HTML page.  Both work fine.

X3D version 4 merely needs to allow alignment with HTML5 rules & relaxations when running in an HTML5 browser.  Since HTML browsers parse page and scene data, it seems unlikely that anything we might define would override that.

Regarding events:
-  DOM events pass a value from one element/node to another, always as a string.
- X3D events pass a value from one element/node to another, always as timestamped typed value - which have defined expressions as a string.
- Reconcilable.

Given the stability of browser environments, which took 14 years to achieve when going from HTML4 to HTML5, we have a better environment for achieving excellent compatibility than at any time in our history.

Regarding implementations: it is not reasonable to ask X3D players to always act in a DOM way.  They are different environments.  Those that want to use DOM for operations are welcome to.

2. Regarding X3D Script and X3D prototype: don't use them if you don't want them.  But don't forbid others from using so much great work, repeatedly implemented with success.  X3D would be much smaller and poorer without prototype extensibility, it allowed us to build large portions of the language.

3. Regarding Consortium:  you seem to think that some kind of decision is needed.  We have a strategy, and we have lots of eyes on it, and we have steady progress, and we can use lots more.  Encouraging activity is not accomplished by opinions or subjective insider decisions.  We have goals, requirements, process and proven track record across 2.5 versions of VRML, 4 versions of X3D, H-Anim, multiple encodings, multiple language bindings, all of which continue to grow compatibly with increasing quality & consistency in each passing month.  None (I repeat, none) of that was achieved by "leadership decisions" that told volunteers how to spend their time.  All of that progress was achieved by cooperative engagement, building consensus, and working hard to implement and evaluate.  Specifications, example scenes and software implementations are the proof points.

Not listening to repeated answers makes repetition of questions of limited use.  "Too long didn't read" indeed.

Using your issues to help define issues/pros + cons/resolutions can contribute to a constructive working group process that has a lot of usefulness.

Traits like "dominant" or popular or common or whatever can be good guidelines, but they are not the bottom line.  Well-defined, repeatable functional correctness is.  This is why we have specifications, examples, implementation and evaluation - for HTML as well as X3D.  This is why we have cooperation between standards development organizations like W3C and Web3D.  That is why we have standardization strategies for HTML5, MAR/VR etc. all worked out collaboratively and posted online.  That is why today we are NOT saying "well a couple of people made a personal decision 5-10-20 years ago that we are forced to live with."

I hope that this note helps explain to everyone how we continue to make progress.

On 6/7/2016 9:29 PM, Leonard Daly wrote:
> Wednesday (8 June 2016) X3D WG call is dedicated to discussion X3D V4. Several people (including myself) have commented on the ideas over the last couple of years. I am going to state my current position here. I don't think it differs much from my position a year ago; however, I'm sure there have been some clarifications.
>
> tl;dr
>
>     X3D needs to run in the HTML5/DOM environment. A few nodes need to be removed, but all capabilities remain.
>
>     Preliminary proposed V4 document at: http://tools.realism.com/specification/x3d-v40
>
>
> I am going to start my position with a response to a question asked by John Carlson on a different list (x3dom-users): are we adding HTML5 capabilities to X3D or 3D (X3D in particular) capabilities to HTML5?
>
> HTML is the dominant environment world-wide. It provides text, image, 2D graphics (SVG), video, and other capabilities. The size of the HTML5 development community far exceeds the total of the entire X3D community. Forcing HTML5 into X3D is a losing game right from the start -- whether you want all of HTML5 or just a portion. So in my mind, the only choice with a future is to add 3D to HTML5. Running in the HTML5 environment means full integration with the HTML5 DOM (or later versions when they happen). BTW, there are already a number of non-Web3D Consortium efforts to do so. We are not out in front of the effort and are about to be made irrelevant. There is no more time for delays or debates.
>
> So now that the environment is settled, it is important to identify what in current X3D (V3.3) is incompatible with HTML5. There are only three obvious features - Script node, event handling, and case sensitivity. There are other capabilities that are dependent on these capabilities -- I'll discuss those later.
>
> Starting with the easiest one first - case sensitivity. HTML5 is case insensitive. Relaxing X3D's rules on that allows existing X3D code to run in a browser. If everything gets converted to lower-case prior to handling (except quoted strings), then there is not a problem.
>
> There is an obvious naming incompatibility with Script -- the name. HTML5 is already using that name. Under my initial condition there cannot be an X3D Script node. That does not mean all scripting functions are given up. HTML5 provides a wonderful script interface a more flexible structure. In X3D, Scripts are meant to process events, so the function argument is always an event (except for X3D-Script internal functions). Functions in HTML5 are a lot more flexible and can include events, objects, scalars, arrays, etc. So there is no loss of functionality by giving up X3D-Script.
>
> Event handling is different between HTML5 and X3D. In X3D events are "routed" from one node to another. They allow one part of the scene graph to "talk" to another part. In HTML5, events "bubble-up" from the originator to the event through any handler that may be attached to any parent node of the originator until the event is cancelled. In all of my design work on V4 I have not found any instance where HTML5-Scripts could not provide the same functionality as X3D-Script+ROUTE. It requires a little different mind-set, but the HTML5 mind-set is very familiar to JavaScript programmers and other front-end developers. I also believe that a graphical development interface can be built that completely simplifies the differences.
>
> The biggest issue I have seen with event handling is scene graph updating. X3D updates the scene graph once all non-looping events in the cascade have completed. After the scene graph is updated, a new frame is rendered. This can cause a large delay between rendered frames. HTML5 renders as it goes. Rendering happens asynchronously to changes to the DOM. There is no concept of accessing the DOM before or after all events for that frame. X3D worlds that depend on that feature will probably not be able to be ported to X3D V4.
>
> Summarizing the three incompatibilities - with the exception of some event processing, none will prevent X3D from doing what it currently can do and all can be easily migrated to the HTML5 environment.
>
>
> There are a number of features that I think should not be included in X3D V4, but these are just features and not fundamental capabilities. These include all nodes that generate geometry (e.g., Extrusion, ElevationGrid, Text) with the exception of simple solids and perhaps a couple of additions. My view here is based on the availability of free modeling software (e.g., Blender) that does all of the above, and a lot more efficiently than X3D can. Also by not including these nodes, the resultant models will look better.
>
> Lastly (for now), I believe that there is no purpose for a PROTO node. Without a X3D-Script node, PROTOs just become convenience generators. To replace that feature, I am proposing a MACRO node that takes X3D and does string substitution prior to inserting the result into the scene graph (and DOM). I have a partial implementation of this for X3DOM.
>
> Summarizing: The Consortium needs to get out and lead the way for 3D on the web (and this includes VR) or it will be by-passed and left with the relics of history like blinking text, and Flash. The environment must be HTML5/DOM and X3D must stay current with the web environment. There will always be someone who needs something specialized that does not use a web environment, but those will be individual cases and not worth significant volunteer efforts.
>
> --
> *Leonard Daly*
> 3D Systems & Cloud Consultant
> X3D Co-Chair on Sabbatical
> LA ACM SIGGRAPH Chair
> President, Daly Realism - /Creating the Future/

all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman