[x3d-public] Problem in x3dviewscene: ROUTE placement
GPU Group
gpugroup at gmail.com
Mon Jun 12 12:10:59 PDT 2023
ROUTES apply in a context: Scene/ProtoBody. If you were developing an
authoring tool, and you read in a scene with ROUTEs anywhere in the
context, you'll be scraping the ROUTES out of anywhere and putting them in
a context-specific routes list. Then when you write out the scene, at the
end of the context you'll spit out the list of ROUTEs.
So there's no reason not to put ROUTES at the root level of the context.
Except if you are re-DEFing (using the same DEF name multiple times down
the scenegraph, thereby re-defining what the DEF name refers to) then you
would want the ROUTEs close / just after the DEF is applied to the node you
want to ROUTE to/from. I think.
On Mon, Jun 12, 2023 at 1:00 PM GPU Group <gpugroup at gmail.com> wrote:
> FreeWRL - OK (Scene root node list is a node list, as is proto root node
> list, and in general node lists OK placement for ROUTEs in classic file for
> freeWRL. Parser scrapes them out of MFlist so they don't show in the MFNode
> list in scenegraph)
> InstantPlayer - OK
> Octaga - OK
> H3D - syntax error, unexpected ROUTE, expecting identifier or SCRIPT or
> DEF or USE
> WDune - syntax error
>
>
>
> On Mon, Jun 12, 2023 at 12:08 PM Vincent Marchetti <vmarchetti at kshell.com>
> wrote:
>
>> My understanding of these results is:
>>
>> > On Jun 12, 2023, at 1:41 PM, Joseph D Williams <joedwil at earthlink.net>
>> wrote:
>> >
>> > No, not tool-generated code. This has run like I show with all
>> available players for 15 or more years without the need to fix.
>> > Found this problem in view3dscene when I began to use it when skin
>> started working; looking forward to displacer.
>> >
>> > Interesting enough, the sequences:
>> >
>> > Group {
>> > Children [
>> > Node { … ]
>> > ]
>> > ROUTE …
>> > }
>>
>> In this case, the ROUTE statement is in the body of the Group node,
>> alongside the fields of the Group node, as clearly allowed by
>> the Architecture specification and the ClassicVRML grammar.
>>
>>
>>
>>
>> > And
>> >
>> > Group {
>> > Children [
>> > Node { … ]
>> > ] }
>> > ROUTE …
>>
>> In this case, the ROUTE statement is at the root level of the Scene,
>> alongside the Group node, as allowed by
>> the Architecture specification and the ClassicVRML grammar.
>>
>>
>>
>> > Are both ok by view3dscene.
>> >
>> > Just does not like:
>> >
>> > Group {
>> > Children [
>> > Node { … ]
>> > ROUTE …
>> > ] }
>>
>> In this case the ROUTE statement appears as one item in the MFNode-typed
>> Children field. The validity of this has been under discussion in this
>> thread. I believe the Architecture prose is ambiguous at best, but that
>> this is forbidden by the ClassciVRML formal grammar.
>>
>> It appears to me that other implementors of the ClassicVRML reading chose
>> to accept the invalid placement of the ROUTE statement. I can't speak for
>> Michalis' intentions, but the view3dscene ClassicVRML import does reject
>> what I judge to be invalid syntax.
>>
>> Vince Marchetti
>>
>>
>>
>> > Thanks,
>> > Joe
>> >
>> >
>> >
>> >
>> >
>> > From: Vincent Marchetti
>> > Sent: Monday, June 12, 2023 6:55 AM
>> > To: X3D-Public
>> > Subject: Re: [x3d-public] Problem in x3dviewscene: ROUTE placement
>> >
>> > Thank you for identifying the relevant seection of the X3D V4
>> Architecture. The relevant sentence from section 4.4.8.2 is:
>> >
>> > ROUTE statements may either appear at the top level of an X3D file or
>> inside a node wherever fields may appear.
>> >
>> > It declares the intent of allowing a ROUTE statement inside a node
>> definition in close proximity to a field that the ROUTE modifies, for
>> purpose of readability, but other than that purpose this placement of the
>> ROUTE statement does not change the semantics of a ROUTE statement. I
>> don't think this sentence bears being taken literally to an extreme;
>> otherwise we are obligated to define a additional XML encoding of the ROUTE
>> statement which allows the ROUTE statement to be included as an XML
>> attribute; so that, for example, it can be placed adjacent to the XML
>> encoding of the SFVec3f "translation" field of the Transform element. I am
>> not trying to argue by exaggeration;t I am argujng that the sentence need
>> to be interpreted in accordance with the syntax of a specific encoding.
>> >
>> > The ClassicVRML encoding does allow a ROUTE to be defined in the body
>> of a X3D node; the specific issue we are discussing is whether this
>> includes placing the ROUTE definition inside the ClassicVRML encoding of an
>> MFNode value. We could have a continued discussion about whether inclusion
>> as an item in a MFNode value is included in the text phrase "..wherever
>> fields may appear", but we can also refer to the formal grammar definition
>> of the ClassicVRML appendix which, in my judgement, does not allow that.
>> >
>> > Taking a step back, and asuming that the JoeLevel2LOA3SSPYRWRJKHud.x3dv
>> example was generated by a tool; we have one tool that generates an x3dv
>> file which does not conform to the ClassicVRML formal geometry published in
>> X3D V3.3 . If I understand Don's email report of June 9, the X3D conversion
>> of the x3dv file passed validation, but this was not direct validation of
>> the original x3dv file. So I see the validation situation as:
>> >
>> > 1) The view3dscene code identifies the ClassicVRML error in
>> JoeLevel2LOA3SSPYRWRJKHud.x3dv when asked to render it,'
>> > 2) The conversion code, from x3dv -> x3d, offered by view3dscene, does
>> not flag an error in JoeLevel2LOA3SSPYRWRJKHud.x3dv but does generate a
>> valid x3d scene from it,
>> >
>> > In the example archives, we have not yet identified a ClassicVRML
>> encoding that includes this very specific feature, a ROUTE statement
>> included within an MFNode value of an X3D field, so it is not yet possible
>> to use our example archive for guidance.
>> >
>> > I think these considerations make it premature to change the
>> ClassicVRML grammar definition in the standard.
>> >
>> > Vince Marchetti
>> >
>> >
>> >
>> > > On Jun 12, 2023, at 1:36 AM, Brutzman, Donald (Don) (CIV) <
>> brutzman at nps.edu> wrote:
>> > >
>> > > • Sorry to be unclear, that was not the relevant
>> reference, rather the prior email in the thread.
>> > >
>> > > My mail of 9 June 16:30:04 PDT 2023 holds the relevant reference.
>> Excerpt follows, quoting a quote, and have provided yellow highlights to
>> key phrasing this time.
>> > >
>> > >
>> > > • [x3d-public] Problem in x3dviewscene: ROUTE placement
>> > > •
>> http://web3d.org/pipermail/x3d-public_web3d.org/2023-June/018836.html
>> > >
>> > > The intent for ROUTE is that it might appear within other nodes. The
>> > > phrasing in X3D4 Architecture is quite explicit about this:
>> > >
>> > > * X3D 4.0 Part 1: Architecture and base components, clause 4
>> Concepts, 4.4.8.2 Routes
>> > > *
>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-IS.proof/Part01/concepts.html#Routes
>> > >
>> > > * Routes allows an author to declaratively connect the output
>> events
>> > > of a node to input events of other nodes, providing a way to implement
>> > > complex behaviors without imperative programming. When a routed
>> output event
>> > > is fired, the corresponding destination input event receives
>> notification
>> > > and can process a response to that change. This processing can change
>> the
>> > > state of the node, generate additional events, or change the
>> structure of
>> > > the scene graph. Routes may be created declaratively in an X3D file or
>> > > programmatically via an SAI call.
>> > > * Routes are not nodes. The ROUTE statement is a construct for
>> > > establishing event paths between specified fields of nodes. ROUTE
>> statements
>> > > may either appear at the top level of an X3D file or inside a node
>> wherever
>> > > fields may appear. A ROUTE statement shall only appear after the
>> definition
>> > > of the source and destination nodes. Placing a ROUTE statement within
>> a node
>> > > does not associate it with that node in any way. A ROUTE statement
>> does
>> > > follow the name scoping rules as described in 4.4.7 Run-time name
>> scope.
>> > >
>> > >
>> > > • I next took the offered example scene
>> > > •
>> https://www.web3d.org/x3d/content/examples/Vrml2Sourcebook/Chapter08AnimatingPositionOrientationScale/Figure08_3PositionInterpolator.x3d
>> > >
>> > > and moved entire scene graph within Scene inside a Group, i.e.
>> > > • <Scene><Group><!—everything including ROUTE statements
>> --></Group></Scene>
>> > > • Thus nothing remains in top-level MFNode list of the
>> scene, except for single parent Group
>> > >
>> > > Then tested the modified example.
>> > > • All validation tests passed.
>> > > • Xj3D worked.
>> > > • X3DOM worked.
>> > > • After 10 minutes of reporting to Microsoft that
>> view3dscene was legitimate, and coercing Windows 10 to accept it,
>> view3dscene.exe worked on this modified example too.
>> > > • Searching for “<ROUTE” found 4989 matches in first 500
>> scenes searched (out of 4060 total archived scenes) so no doubt there are
>> more.
>> > >
>> > > • To my prior list of benefits for flexible placement of
>> ROUTE statements, here is another:
>> > > • Simplifies author and tool addition of code-block
>> patterns and templates within a scene (this a feature used numerous times
>> as an optional authoring assist for event tracing by X3D-Edit, likely to be
>> added as utility features in X3DJSAIL and X3DPSAIL someday as well.)
>> > > Specifically, from X3D-Edit documentation,
>> > > • Trace capabilities are available for ROUTE, sensors,
>> interpolators and other nodes that produce or consume events. Trace output
>> results are logged on the browser console to show the timing and values
>> passed events. When the Trace checkbox is selected by the author, a Script
>> node is inserted immediately after the node to accomplish this task. This
>> is a useful debugging technique.
>> > > •
>> https://savage.nps.edu/X3D-Edit/images/TraceFeatureReportsRoutedEventValuesOnBrowserConsoleViaScriptOutput.png
>> > > •
>> https://x3dgraphics.com/examples/X3dForWebAuthors/Chapter07-EventAnimationInterpolation/Chapter07-EventAnimationInterpolation-EventTracing.pdf
>> > >
>> > > • “Consistency across all file encodings and language
>> bindings is possible.” This is our basic design principle for separation of
>> functionality in X3D architecture from implementation details in all
>> related specifications.
>> > >
>> > > We have immense interoperability already. As promised many times, we
>> will smooth out any mismatches in future X3D 4.0 file encodings and
>> language bindings. Test cases do help too. So stand by for action.
>> > >
>> > > Hopefully the highlighted specification requirement, the ease of
>> creating flexible test cases, and the value of this existing specification
>> capability is presented more clearly now.
>> > >
>> > > Careful consideration, implementation efforts, and consensus-based
>> progress are always appreciated.
>> > >
>> > > Having fun with X3D… I hope that others are too.
>> > >
>> > > 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
>> https://faculty.nps.edu/brutzman
>> > >
>> > > From: vmarchetti at kshell.com <vmarchetti at kshell.com>
>> > > Sent: Sunday, June 11, 2023 4:42 PM
>> > > To: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>; X3D-Public <
>> x3d-public at web3d.org>
>> > > Cc: Michalis Kamburelis <michalis.kambi at gmail.com>
>> > > Subject: Re: [x3d-public] Problem in x3dviewscene: ROUTE placement
>> > >
>> > >
>> > > On Jun 11, 2023, at 5:09 PM, Brutzman, Donald (Don) (CIV) <
>> brutzman at nps.edu> wrote:
>> > >
>> > > Not trying to invent anything here, rather point out what is
>> specified (and also common practice). I already gave the relevant links in
>> the X3D 4.0 Architecture governing what is required.
>> > >
>> > > I do not see this requirement given or even implied in the link you
>> specified:
>> > > •
>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-IS.proof/Part01/fieldTypes.html
>> > >
>> > > is a comprehensive listing of the X3D Field types, with details on
>> SFNode and MFNode therein, and on this page I don't see any mention of the
>> ROUTE statement nor does a text search on that page discover even the terms
>> "route" or "statement" in isolation.
>> > >
>> > > ...
>> > >
>> > >
>> > > Consistency across all file encodings and language bindings is
>> possible.
>> > > I don't this this statement is true, or to the extent that it is
>> true, then long - ago X3D design decisions did not treat it as of primary
>> importance. As Michalis pointed out, in the ClassicVRML encoding the zero
>> or more items in a single MFNode value are syntactically enclosed in square
>> brackets. Moreover, in the ClassicVRML encoding all the field values are
>> explicitly identified with the name of the field. However, in the X3D
>> encoding the XML child elements are in most cases identified as belonging
>> to an X3D field through the node type-inheritance classification; and in
>> the few cases where that is not possible an explicit "containerField" XML
>> attribute is used. To make the X3D encoding consistent with ClassicVRML
>> would entail the use of wrapper XML elements around the element encoding of
>> one node-element for an SFNode value, or the several nodes of MFNode.
>> However, the design decision was made long ago not to use wrapper elements
>> in the XML encoding ( see
>> https://www.web3d.org/x3d/content/examples/Basic/development/WrapperTagsConsideredHarmful.html
>> )
>> > >
>> > > My point is that the consistency among encodings is a useful criteria
>> but should not automatically take precedence over other considerations. One
>> such consideration is maintainging stability of our formal ClassicVRML
>> grammar.
>> > >
>> > > And I think there is little additional benefit in changing the the
>> ClassicVRML to allow ROUTE inside MFNode encodings. Doing so does allow a
>> ROUTE to be placed adjacent to a node whose fields it modifies and you
>> (Don) have pointed out the readability benefits that offers -- but Michalis
>> points out that the ClassicVRML already allows that ROUTE statement to be
>> placed inside the body of a node it modifies, even closer!
>> > >
>> > > Vince Marchetti
>> >
>> >
>> > _______________________________________________
>> > x3d-public mailing list
>> > x3d-public at web3d.org
>> > http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>>
>>
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>
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