Re: [www-vrml] X3D EXTERNPROTO [was: VRML still the most ...]

[Leonard Daly <daly@realism.com>]

Paul,

A browser-specific node should be identified as belonging to that
particular browser. So BTC calls their nodes BTC_. Xj3D is (already)
using xj3d_. This tells content developers that this node is particular
to that browser. No individual browser builder should call their node
Joystick. That way you don't have "generic" node names that
have browser-specific features. It helps ensure cross-browser
compatibility.

If there is sufficient support or interest in the community (meaning
Web3D members), the X3D Specification WG will take up the matter of
adding the new node to the base specification. The Specification WG will
evaluate the request for a new node. Included in the evaluation will be
breath of interest, compatibility with the specification, and IP issues.
If the WG accepts the need for the new node, then it will be scheduled
into a suitable amendment to the spec. In the example, the new node would
be called Joystick.

There is nothing in this process that would break existing content.
However, a browser builder may choose to drop support for their node
(e.g., BTC_Joystick) at some point in their development cycle. If that
were to happen, then (obviously) existing content that depended upon that
node would fail.

It is important for content developers to choose the right environment
for their material. If the content is intended to be distributed widely
into environments beyond the control of the developer, it is best to
stick with the nodes in the specification. If it is a controlled
environment, then the best browser (by whatever measure you choose) can
be used for the job.

        

Leonard
Daly



At 06:34 AM 9/4/04, Paul Aslin wrote:

Yes but what happens when there are TWO browser builders
which support the same new node as an inbuilt feature ?

Or perhaps more seriously what happens when other companies
add support for the new node to their own products, would
this create problems for content created before that time ?

--- Leonard Daly <daly@realism.com> wrote:

> The spec team had a lot of discussion of EXTERNPROTO. As
> a content
> developer capability, there is no change from VRML97. The
> change does come
> about for browser writers. In X3D you cannot use the
> EXTERNPROTO mechanism
> to provide an interface for new nodes. New nodes are
> built into the browser
> and should not use an EXTERNPROTO interface.
>
> So if the browser builder BTC decides to add a node that
> supports a 6DoF
> joystick, they could add a node (e.g., BTC_Joystick) for
> this purpose.
> There would be no EXTERNPROTO that content developers
> would reference.
> Content developers would access this new node in the
> 'Component' statement
> (e.g., 'Component BTC:1').
>
> This new node would be only available in the BTC browser.
> Support for it
> would not be required (and may actually be prohibited) in
> other browsers.
>
>
> If you are a content developer creating EXTERNPROTO, then
> you can use any
> node available to you (for the Profile and Component that
> you declare). If
> you do choose to refer to a node like BTC_Joystick, then
> it needs to be
> declared in the EXTERNPROTO and in the top level X3D
> file.
>
>
>          Leonard Daly
>
>
>
> At 07:24 AM 9/3/04, George Birbilis wrote:
> > > >   X3D is just integration plus more features.
> > >
> > > <http://www.web3d.org/x3d/faq/index.html#technical-2>
> > >
> > > The abandonment of EXTERNPROTO as a browser extension
> mechanism should
> > > not be trivialized. The text in the above link says
> that, "The way to
> > > provide browser-specific extensions is through custom
> components." But
> > > how do you refer to one of these "custom components"
> over the network?
> >
> >Hi Braden,
> >I believe the idea is that once the browser sees a
> component it doesn't know
> >mentioned in the header of a X3D file, tries to contact
> the browser vendor's
> >host (or some local network repository folder set in
> browser options) and
> >check for a plugin/update to add support for that
> component (say one had
> >installed the browser with minimum components for quick
> download) and if it
> >doesn't find such it shows message to the user...
> >
> >...probably also playing it nice and showing some dialog
> to the user with
> >the other X3D browsers found in the system to chose one
> to use (can do that
> >on Windows using the registry), showing only those
> browsers that have marked
> >in the registry that they support that component
> (supposing W3D group
> >defines the format for such info in the registry and
> what's the min required
> >info to have there for an X3D browser)
> >
> >cheers,
> >George
> >
> >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >George Birbilis <birbilis@kagi.com> [Microsoft MVP J#]
> >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >+ QuickTime VCL and ActiveX controls (for
> PowerPoint/VB/Delphi etc.)
> >+ Plugs VCL and ActiveX controls (InterProcess/Internet
> communication)
> >+ TransFormations, VB6 forms to ASP.net WebForms
> convertion
> >http://www.kagi.com/birbilis
> >+ Robotics
> >http://www.mech.upatras.gr/~robgroup
>
>........................................................................
> >
>
>-------------------------------------------------------------------------
> >for list subscription/unscrubscription,
> >go to
>
http://www.web3d.org/cgi-bin/public_list_signup/lwgate/listsavail.html
>
> +--------
> | Leonard Daly <daly@realism.com>
> | Internet Development http://realism.com/
> | e3D News Technical Editor http://e3dNews.com/
> | SIGGRAPH 2002&2003 X3D Course Organizer
> | Member, Web3D Board of Directors
> +------------------------------
>



                
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+--------
| Leonard Daly <daly@realism.com>
| Internet Development http://realism.com/
| e3D News Technical Editor http://e3dNews.com/
| SIGGRAPH 2002&2003 X3D Course Organizer
| Member, Web3D Board of Directors
+------------------------------