[x3d-public] good example for ECMAScripting and Protos?
Leonard Daly
Leonard.Daly at realism.com
Mon Aug 6 10:41:38 PDT 2018
John,
In HTML a node can only appear once in the DOM. It is not possible for a
DOM node to DEF/USE in the sense that X3D requires it. It is not
required for the 3D scene graph to be in the DOM. That makes the 3D
content, data within the HTML page. From that perspective (and speaking
of X3D here), X3D would be embedded in the HTML page, but not part of
the DOM. This is somewhat equivalent to using a 'data:' URI for an
image. The information would be all there, but the individual nodes
would not be accessible as DOM nodes unless explicitly added by the code
processing the 'data:' URI.
As far as I have been able to tell (and I have been studying this issue
for 3+ years), the choice is
1) Include X3D code (tags, protos, scripts, etc.) as data within the
HTML page and do have it as nodes in the DOM
2) Change X3D so it is compatible with and follows the rules HTML5
making X3D nodes full members of the DOM
3) Change HTML5 so it is compatible with X3D.
4) Decide that X3D and HTML5 exist is two separate spaces and should not
be integrated.
(1) is certainly an option and (I think, perhaps Andreas should comment
here) this is similar to what X_ITE does
(2) has been raised for several years and some people are absolutely
opposed to this
(3) not going to happen
(4) not an expressed desired of the Consortium.
XSeen has taken the (2) approach. It supports the DEF/USE concept for
selected (proper) subset of node capabilities. It also focuses on
assembly / integration of scene components rather than modeling objects.
It is expected that most models will be provided by glTF.
Leonard Daly
> Leonard, I agree my approach may not work in all environments.
>
> Determining a valid or invalid mime type is extremely difficult if
> done semantically, but extremely easy if done syntactically. My guess
> is that many of the X3D tags are semantically invalid, unless someone
> has added them to Apache. I do not know the status of this. I have
> to add mine types to my server for every new extension I add. It is
> not a that big of a deal.
>
> One may not need a script tag around X3D script to execute X3D
> script. One may use eval in a script tag. One may make script
> inconsequential by making the scripts only functions, and move the
> functions to a string which is evaled. Essentially you are parsing twice.
>
> If we want script fields handled by X3DOM, we will have to find
> someway to bring them into X3DOM. X_ITE has shown the way. We can
> take other approaches than X3DOM, like straight DOM. I am beginning
> to think this is preferable, but using DEF to find node which aren’t
> in the scenegraph has kind of been, wtf?
>
> The question has become “Are DEFed SFNodes valid scenegraph objects if
> they are in fields?” This may show a failing of X3DOM, which may need
> to be corrected. I can probably find the scengraph object using USE,
> but I really want to use DEF. Can someone show me how to do it in
> the HTML5 environment?
>
> John
> On Mon, Aug 6, 2018 at 12:24 AM Leonard Daly <Leonard.Daly at realism.com
> <mailto:Leonard.Daly at realism.com>> wrote:
>
> I am replying to an early message in this thread, but I hope to
> capture comments from all messages in the thread. My comments only
> apply to the web browser (HTML5) environment.
>
> First, any Script tag (in any case) will be handled by the web
> browser, and the web browser will parse content before anything
> else. If you really need to independently parse some tags, you
> will need to "read" it into a JavaScript variable and handle it
> that way. If it's in the page file, it will be parsed.
>
> There was a suggestion to use "text/x3dscript" or some other
> string. The W3C has something to say about this at
> https://www.w3.org/TR/html5/scripting-1.html#the-script-element.
> The value of the type attribute must either be
>
> 1. omitted
> 2. JavaScript MIME type
> 3. "module"
> 4. any other valid mime type
>
> So the use of an invalid MIME type is not technically valid HTML.
> This may cause a problem with some browsers or validators; or
> present future problems if that string is ever defined to have a
> particular meaning.
>
> X3DOM does not have X3D scripting. If you need scripting to
> correctly process an X3DOM environment; then you need to do it in
> HTML5 Javascript. X3DOM does not process the Script tag, that is
> done by HTML5. While X3DOM parser could recognize that tag, it
> does not; hence, none of the X3DOM methods are available to handle
> interactions on a Script node (a Script tag parsed into DOM).
>
> The X3D Script / HTML5 Script tag name conflict is a long-standing
> and known issue. To my knowledge no work has been done to break
> the conflict.
>
> Leonard Daly
>
>
>
>
>
>> Here’s my current code for clearing the ECMAScript out of a X3D
>> file so that it doesn’t show on the screen:
>>
>> $(selector+" Script").contents().filter(function () {
>>
>> return this.nodeType === 3 || this.nodeType === 4;
>>
>> }).remove();
>>
>> This retains the fields. I may change my code to work with
>> fields instead of parsing out the fields into properties (but
>> directOutput is nice). This would mean that X3DOM has to route
>> to and from the script fields (is this possible?).
>>
>> John
>>
>> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986>
>> for Windows 10
>>
>> *From: *John Carlson <mailto:yottzumm at gmail.com>
>> *Sent: *Saturday, August 4, 2018 4:56 AM
>> *To: *vmarchetti at kshell.com <mailto:vmarchetti at kshell.com>;
>> X3D-Public <mailto:x3d-public at web3d.org>; x3dom mlist
>> <mailto:x3dom-users at lists.sourceforge.net>; Andreas Plesch
>> <mailto:andreasplesch at gmail.com>
>> *Subject: *RE: [x3d-public] good example for ECMAScripting and
>> Protos?
>>
>> I have a problem with this file in X3DOM, because as far as I can
>> tell, the SFNode fields (the node, not the field) do not have
>> getFieldValue for point etc. as a function, for example (but one
>> can double check me). In other words, I don’t think this node is
>> an X3DOM node.
>>
>> Thus I cannot take a reasonable length in the script. One would
>> have to parse the string.
>>
>>
>> That’s as clear as I can get. I think this might be because
>> x3dom does not process scripts correctly. We would need a script
>> tag handler, and a field handler inside that.
>>
>> Can you help Andreas? I’ve created a script tag before, but that
>> code is lost. It might be in my GitHub repository somewhere, not
>> sure.
>>
>> We just need a script tag that has fields, but doesn’t execute
>> its CDATA section. I am pretty sure
>>
>> How is V4.0 handling this?
>>
>> Alternatively, I can change my nodeUtil code to look at the type
>> and do the right thing converting a string to the correct type.
>> Suggestions are welcome.
>>
>> Thanks for the great example, Vince,
>>
>> Should I adapt my code to deal with this failing in X3DOM, or
>> should we change X3DOM?
>>
>> John
>>
>> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986>
>> for Windows 10
>>
>> *From: *vmarchetti at kshell.com <mailto:vmarchetti at kshell.com>
>> *Sent: *Wednesday, August 1, 2018 9:04 PM
>> *To: *John Carlson <mailto:yottzumm at gmail.com>; X3D-Public
>> <mailto:x3d-public at web3d.org>
>> *Subject: *Re: [x3d-public] good example for ECMAScripting and
>> Protos?
>>
>> See
>>
>> http://www.kshell.com/pages/pointcloudvisualization/SphereDirectedPointSet.x3d
>>
>> It is a X3D file with with a Prototype + ecmascript definition of
>> a point cloud, with a vector attached to each point of the cloud.
>>
>> Example used is just points randomly distributed on sphere with
>> directs pointed radially outward.
>>
>> Potential uses would be to implement the scanning design pattern
>> at
>> http://x3dgraphics.com/examples/X3dForAdvancedModeling/Scanning/X3dMeshDesignPatternIndex.html
>> , or
>>
>> visualizing fluid flow or electromagnetic field
>>
>> On Jul 31, 2018, at 10:30 PM, John Carlson
>> <yottzumm at gmail.com> <mailto:yottzumm at gmail.com> wrote:
>>
>> Is there a good example of ECMAScripting in X3D that I can
>> use to test my X3D JSON ECMAScript preprocessor? Preferably
>> with Protos
>>
>> Thanks!
>>
>> John
>>
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>
>
> --
> *Leonard Daly*
> 3D Systems & Cloud Consultant
> LA ACM SIGGRAPH Past Chair
> President, Daly Realism - /Creating the Future/
>
--
*Leonard Daly*
3D Systems & Cloud Consultant
LA ACM SIGGRAPH Past Chair
President, Daly Realism - /Creating the Future/
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