[x3d-public] Script Illustrative Example [was: X3D Specification Relationships diagram]
Leonard Daly
Leonard.Daly at realism.com
Mon Aug 14 09:47:19 PDT 2017
Andreas,
This is very interesting. Cobweb's Script node has access to HTML
functions. In this case the calculation of the Y position is done in
HTML script code, while passing values is done in X3D Script code. Since
JavaScript interprets anything of the form label(...) as a function with
the name 'label', handles line 69 ("value_changed.y =
changeY(value_changed.y, time - time0, time);//time is in seconds") just
fine.
This method appears to create a subset of the JavaScript environment
where the functions all take two arguments (event-data, event-time) and
return one or more values ('value-changed' in this example). I think
this could also be implemented where each X3D Script function was an
internal method of some (HTML) JavaScript object and the object provided
control and data handling.
Does Cobweb keep the script names in a protected environment, e.g., as
an anonymous script stored in a variable. IOW, would it be possible to
overwrite an X3D Script code by storing another script in an
appropriately labeled variable?
Leonard Daly
> And here is a version which mixes x3d and html scripting:
>
> https://x3d-v4-mixed-scripting.glitch.me/
> <https://x3d-v4-mixed-scripting.glitch.me/>
> forkable source:
> https://glitch.com/edit/#!/x3d-v4-mixed-scripting?path=index.html:69:4
> <https://glitch.com/edit/#%21/x3d-v4-mixed-scripting?path=index.html:69:4>
>
> The idea to use a redefinable global function in a x3d field function
> worked fine.
>
> Above now uses regular x3d animation via timesensor and routes. The
> x3d script acts as an interpolator accepting set_fraction input. It
> does end up not using the fraction since the original animation was
> defined in terms of clock time. So the script also uses timestamps and
> the original changeY and linearX global html script functions. The
> redefinition of changeY via button names is unchanged.
>
> It would be nicer to define the interpolators in terms of a fraction
> but that is secondary.
>
> The x3dom approach would be to use its onOutputChange event:
> https://doc.x3dom.org/tutorials/animationInteraction/onoutputchange/index.html
>
> for defining a custom interpolator.
>
> -Andreas
>
> On Sat, Aug 12, 2017 at 10:40 AM, Andreas Plesch
> <andreasplesch at gmail.com <mailto:andreasplesch at gmail.com>> wrote:
>
> Hi Leonard,
>
> here is a version of the example which uses cobweb with cobweb-dom
> for DOM API use.
>
> https://x3d-v4-scripting-cobweb.glitch.me/
> <https://x3d-v4-scripting-cobweb.glitch.me/>
> and
> https://glitch.com/edit/#!/x3d-v4-scripting-cobweb?path=index.html:63:1
> <https://glitch.com/edit/#%21/x3d-v4-scripting-cobweb?path=index.html:63:1>
>
> The necessary changes were minor:
> - The display area div needed to be replaced with a x3d canvas
> - The ball div needed to become a sphere shape transform
> - The ball position is set via the translation attribute rather
> than position style properties.
>
> The viewpoint is at a distance such that 1px in the original div
> rectangle corresponds to about 1m in the x3d scene when viewed
> from the viewpoint.
>
> Otherwise no changes are needed since full control via the DOM API
> is possible.
>
> I also found that I need to update cobweb-dom to work with the
> latest cobweb since there were some changes in the cobweb parser.
> The current cobweb-dom only works with cobweb < 3.0.
>
> I suppose the next question is if one can use x3d scripts instead
> of the html scripts or somehow mix and match. What functionality
> should be provided in an x3d script ? The tricky thing to try
> maybe to do the animation inside x3d but replace the x3d
> interpolator with a custom interpolator from an html script ?
> Maybe I can think of something.
>
> -Andreas
>
>
>
> On Sat, Aug 12, 2017 at 1:13 AM, Andreas Plesch
> <andreasplesch at gmail.com <mailto:andreasplesch at gmail.com>> wrote:
>
> I went back to the cobweb repo to very carefully read through
> the rather mind bending script node code in
>
> https://github.com/create3000/cobweb/blob/master/cobweb.js/cobweb/Components/Scripting/Script.js
> <https://github.com/create3000/cobweb/blob/master/cobweb.js/cobweb/Components/Scripting/Script.js>
>
> and came to the conclusion that the x3d scripts are only
> evaled once during initialization, contrary to what I had
> thought. The script text is cleverly appended with an array of
> all defined named functions which then becomes the return
> value of the eval call. These functions are then stored in a
> local scope this.context object, essentially as methods. Then,
> whenever a lifecycle function or a field function needs to be
> executed, the context method is called.
>
> One could probably expose this context object and then
> redefine its methods from Dom scripts. However, one would lose
> the cobweb constructed "with" "global" object which allows
> easy and standard access to x3d functions and user defined
> fields. It could be probably reconstructed if needed.
>
> I may try to convert the example to cobweb dom.
>
> Andreas
>
> -The formatting survived the direct mail but not the route
> through the list probably because I receive digests.
>
>
> On Aug 11, 2017 9:03 PM, "Leonard Daly"
> <Leonard.Daly at realism.com <mailto:Leonard.Daly at realism.com>>
> wrote:
>
> I was asked by John to construct an example illustrating
> the items listed below. I also have replies to Andreas'
> comments. The original message is at the bottom (for
> reference). I've copied the relevant questions/statements
> to the top to make reading easier.
>
> First to the example. It is located at
> http://tools.realism.com/development/WG-Support/2017-08-09/ScriptIllustration.html
> <http://tools.realism.com/development/WG-Support/2017-08-09/ScriptIllustration.html>
> It does not use Cobweb since I can't begin to figure out
> how to do this in Cobweb. OTOH, if X3D is DOM integrated,
> then the it shouldn't matter where various functions and
> methods are located.
>
> The example is strictly 2D, but I think it clearly
> illustrates the goal. The default Y interpolator is
> nothing (no change). Selecting different buttons change
> the interpolator in real-time. Each interpolator is
> defined as a function. The variable 'changeY' holds the
> current interpolator. When a button is pressed, the value
> of 'changeY' is set to the selected interpolator. There is
> no 'case' statement the uses the correct interpolator on
> each pass through the animation loop.
>
> John if this doesn't illustrate the concept, please
> explain what you need to see.
>
> Andreas, you have done and continue to do a lot in support
> of web 3D, especially wrt to X3DOM. I continue to be
> impressed with your solutions to problems presented to
> that list. [I'll have one soon, with a potential solution.]
>
>
> AP: Mixing DOM and x3d scripts is inherently problematic
> since x3d scripts expect their own environment (scope).
> But let's see.
> AP: Not sure if x3d scripts should be available globally,
> eg. as window.foo which means foo is global. This would
> mean that any other script or framework needs to be
> careful not to use the same function names.
>
> AP: window.x3d should be nicer, as a dedicated namespace.
> x3dom uses the x3dom namespace.
>
> If X3D and HTML are fully integrated then they will be
> mixed. It is now common practice to put library methods
> into their own namescope. This namescope is not limited,
> but is prefixed by a known library label (e.g., x3dom,
> THREE, etc.). Mandating that X3D in HTML use the 'x3d'
> namescope would cause problems if someone wanted to run
> two different libraries from the same HTML context. iframe
> can fix that, but it seems overly restrictive.
>
>
> function bar(event, time) {
> window.foo = bar; // I would (perhaps) settle for
> window.x3d.foo = bar;
> }
>
>
> AP: This currently does not work since cobweb goes back to
> the original function source each time the script is run.
> But the x3d script could probably use internally a global
> HTML script function which can be redefined at will, to
> enable a hook into an x3d script.
>
> [1]
>
> <Script ...> <!-- X3D Script node -->
> function foo (event, time) {
> window.bar = foo;
> }
> </script>
>
>
> AP: This probably already works since cobweb evals the
> function text almost as is.
>
> Is this the same as
>
> [2]
>
> var foo = function (event, time) {do_work;};
> window.bar = foo;
>
> ?
>
> It seems to me that eval the script text each time,
> especially in an animation loop, is needlessly expensive.
> The two examples (indented if that works in your mail
> reader) are not the same. The first example sets
> window.bar to be 'foo' each time it runs. The second
> example only sets window.bar to be 'foo' after the
> definition is processed. If there is something else
> setting window.bar after the 'foo' function definition is
> processed, then that definition to 'foo' is never used.
>
>
> AP: What does the SAI say about manipulating or calling
> x3d script functions from the outside ? You may only be
> able to remove and add complete script nodes but not work
> with the script functions ?
>
> AP: Proposed text would be great. For now, it may be
> productive to settle for slightly less integration by
> keeping x3d scripts pretty much internal to the x3d
> context but allow x3d scene control via the DOM, eg. make
> x3d nodes similar to svg/html elements.
>
>
> This is my main point. DOM is an API. If X3D chooses to
> define an API in HTML, then it must be done so as not to
> interfere with the DOM API. Developers will use the DOM
> API to do things anyway. X3D should only expand on that,
> not restrict that. Anything less would not be full
> integration. There is no such thing as an SVG Script tag.
> It is located in the same space all all HTML scripts.
>
>
> Leonard Daly
>
> P.S. I hope all of the formatting and styling worked.
>
>
>
>
>
>
> On 8/11/2017 7:33 AM, Andreas Plesch wrote:
>>
>> Date: Thu, 10 Aug 2017 18:31:25 -0700
>> From: Leonard Daly <Leonard.Daly at realism.com
>> <mailto:Leonard.Daly at realism.com>>
>> To: John Carlson <yottzumm at gmail.com
>> <mailto:yottzumm at gmail.com>>, X3D Graphics public mailing
>> list <x3d-public at web3d.org
>> <mailto:x3d-public at web3d.org>>, Web3D Consortium
>> <consortium at web3d.org <mailto:consortium at web3d.org>>
>> Cc: X3D Graphics Working Group <x3d at web3d.org
>> <mailto:x3d at web3d.org>>
>> Subject: Re: [x3d-public] [x3d] X3D Specification
>> Relationships
>> diagram
>>
>>
>> Leonard, thanks for raising this, and I appreciate your
>> attempt to rally broader support around v4 and web
>> compatibility. I continue to do what I can which is not
>> too much these days.
>>
>> On 8/10/2017 5:17 PM, John Carlson wrote:
>> >
>> > Leonard wrote:
>> >
>> > >and node name collisions (i.e., Script).
>> >
>> > There has been quite a bit of progress with this
>> and X3DJSONLD and
>> > X3DOM. It?s been under the covers because I have
>> not advertised it
>> > much. I have several scripts running, but not the
>> full complement of
>> > my examples. It does not run the X3D event model
>> yet, except for
>> > initialize().
>> >
>> > Cobweb of course, already handles this, so quit
>> bellyaching.
>> >
>>
>> Cobweb even with Andreas' DOM interface extensions
>> does not integrate
>> with the DOM regarding Scripts. A full integration
>> would allow the
>> following:
>>
>>
>> Mixing DOM and x3d scripts is inherently problematic
>> since x3d scripts expect their own environment (scope).
>> But let's see.
>>
>> X3D Script function called 'foo'
>> HTML script function called 'bar'
>>
>> In the body of bar, I should be able to redefine
>> 'foo'. It is (in a
>> fully integrated system) available as window.foo.
>> Similarly for inside
>> of 'foo' to change 'bar'.
>>
>>
>> Not sure if x3d scripts should be available globally, eg.
>> as window.foo which means foo is global. This would mean
>> that any other script or framework needs to be careful
>> not to use the same function names.
>>
>> function bar(event, time) {
>> window.foo = bar; // I would (perhaps)
>> settle for
>> window.x3d.foo = bar;
>> }
>>
>>
>> window.x3d should be nicer, as a dedicated namespace.
>> x3dom uses the x3dom namespace.
>>
>> This currently does not work since cobweb goes back to
>> the original function source each time the script is run.
>> But the x3d script could probably use internally a global
>> HTML script function which can be redefined at will, to
>> enable a hook into an x3d script.
>>
>> and
>>
>> <Script ...> <!-- X3D Script node -->
>> function foo (event, time) {
>> window.bar = foo;
>> }
>> </script>
>>
>>
>> This probably already works since cobweb evals the
>> function text almost as is.
>>
>> Is this the same as
>>
>> var foo = function (event, time) {do_work;};
>> window.bar = foo;
>> ?
>>
>> I should be able to construct an object with 'foo' as
>> a method. E.g.,
>>
>> var globalVar = {};
>> globalVar.x3d = foo;
>>
>> // should call the X3D script passing it a reference
>> to the current
>> value of 'event' and 'time'.
>> globalVar.x3d(event, time);
>>
>>
>> It may be possible to 'export' named x3d script functions
>> to window.x3d, so they can be called. cobweb would
>> currently redefine a named function each time an x3d
>> script is executed.
>>
>>
>> Inside 'foo' I should be able to access any DOM
>> element to get it's
>> current state or even establish an event listener.
>>
>>
>> You should be able to do that in cobweb now although it
>> would be strange to find DOM code in an X3D script.
>> Perhaps for HUD of GUI purposes it could be useful, actually.
>>
>>
>> I know there are some things that Cobweb can do, but
>> there has been no
>> discussions in the WG for the language that would be
>> necessary to ensure
>> HTML/DOM/X3D interaction like I described above.
>>
>>
>> What does the SAI say about manipulating or calling x3d
>> script functions from the outside ? You may only be able
>> to remove and add complete script nodes but not work with
>> the script functions ?
>>
>>
>> Unrolling scripts on the server (or at least not in
>> the runtime of the
>> browser) is all fine and good, but again there has
>> been no discussion in
>> the WG as to how to even approach writing that up.
>>
>> I will be happy to be (relatively) quiet on these
>> points if someone can
>> show me working examples and proposed text to make
>> this work.
>>
>>
>> Proposed text would be great. For now, it may be
>> productive to settle for slightly less integration by
>> keeping x3d scripts pretty much internal to the x3d
>> context but allow x3d scene control via the DOM, eg. make
>> x3d nodes similar to svg/html elements.
>>
>> -Andreas
>>
>>
>>
>> --
>> *Leonard Daly*
>> 3D Systems & Cloud Consultant
>> LA ACM SIGGRAPH Chair
>> President, Daly Realism - /Creating the Future/
>> -------------- next part --------------
>> An HTML attachment was scrubbed...
>> URL:
>> <http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20170810/93cc05ca/attachment.html
>> <http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20170810/93cc05ca/attachment.html>>
>>
>> ------------------------------
>>
>> Subject: Digest Footer
>>
>> _______________________________________________
>> x3d-public mailing list
>> x3d-public at web3d.org <mailto:x3d-public at web3d.org>
>> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>> <http://web3d.org/mailman/listinfo/x3d-public_web3d.org>
>>
>>
>> ------------------------------
>>
>> End of x3d-public Digest, Vol 101, Issue 9
>> ******************************************
>>
>>
>> --
>> Andreas Plesch
>> 39 Barbara Rd.
>> Waltham, MA 02453
>>
>>
>> _______________________________________________
>> x3d-public mailing list
>> x3d-public at web3d.org <mailto:x3d-public at web3d.org>
>> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>> <http://web3d.org/mailman/listinfo/x3d-public_web3d.org>
>
>
> --
> *Leonard Daly*
> 3D Systems & Cloud Consultant
> LA ACM SIGGRAPH Chair
> President, Daly Realism - /Creating the Future/
>
>
>
>
> --
> Andreas Plesch
> 39 Barbara Rd.
> Waltham, MA 02453
>
>
>
>
> --
> Andreas Plesch
> 39 Barbara Rd.
> Waltham, MA 02453
--
*Leonard Daly*
3D Systems & Cloud Consultant
LA ACM SIGGRAPH Chair
President, Daly Realism - /Creating the Future/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20170814/65cafd9c/attachment-0001.html>
More information about the x3d-public
mailing list