[x3d-public] Finding more than one use of a DEF in VRML

[John Carlson]

Gotcha.

On Thu, Mar 26, 2020 at 9:50 AM Michalis Kamburelis <
michalis.kambi at gmail.com> wrote:

> There isn't a "name" field general for all nodes. Some specific nodes
> have "name" field, but it's specific to these nodes and their needs
> (MetadataXxx, CADPart, CADLayer, HAnimHumanoid, HAnimJoint,
> X3DVertexAttributeNode etc.). And it has special interpretation (e.g.
> for X3DVertexAttributeNode this "name" is a shader per-vertex
> attribute name).
>
> So when X3D specification (link you posted,
>
> https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/concepts.html#DEFL_USESemantics
> ) talks about """Node names""" -> it means that names assigned using
> DEF. Not names assigned using name="xxx"...
>
> Confusing, I know.
>
> It's an unfortunate collision of terms, the "name of X3D node" can
> indeed be interpreted in various ways, depending on context. When
> someone talks of a general X3D node, then they surely mean "name
> assigned using DEF".
>
> Regards,
> Michalis
>
> czw., 26 mar 2020 o 15:25 John Carlson <yottzumm at gmail.com> napisał(a):
> >
> > Maybe I'm confused.  Are node names
> >
> > name="node name"
> >
> > or
> >
> > DEF="node name"
> >
> > I've been using "DEF value" for "DEF keyword" I think.
> >
> > I think if the DEF keyword is not unique with in a scope, my
> ProtoExpander will blow big chunks, but I'll have to check.
> >
> > There were many discussions on the mailing list about this, and maybe I
> didn't understand because I wasn't phrasing the question properly.
> >
> > In some cases in the wrl previously reported, the DEF keyword is not
> unique in the source file, but I didn't check for the source (that is, I
> didn't inspect the source file very much), there could be additional scope
> stuff like a PROTO.
> >
> > John
> >
> > On Thu, Mar 26, 2020 at 7:25 AM Michalis Kamburelis <
> michalis.kambi at gmail.com> wrote:
> >>
> >> I have to correct myself -- I see x3d 3.3 specification says """Node
> names shall be unique in the context within which the associated DEF
> keyword occurs."""
> >>
> >> All right, that's good. Looks like this rule was improved at some x3d
> version. That's good, it is a better idea to have all names unique (e.g.
> for easy EXPORT).
> >>
> >> It still remains a question why did my converter generate repeated DEF.
> It should not, if source VRML didn't repeat them. I'll look into it --
> please send input to reproduce it:)
> >>
> >> Regards,
> >> Michalis
> >>
> >> W dniu czw., 26.03.2020 o 12:09 Michalis Kamburelis <
> michalis.kambi at gmail.com> napisał(a):
> >>>
> >>> As I mentioned in the other thread, multiple DEF with the same name
> >>> are just allowed by the X3D specification. Last one "wins" (obscuring
> >>> the others with the same name). Maybe they should be disallowed or
> >>> discouraged, it's another discussion. But right now they are allowed
> >>> and proper VRML / X3D reader should understand them.
> >>>
> >>> As to why my exporter created them -- I need to see the relevant input
> >>> file to answer it. There should be a good reason for it :)
> >>>
> >>> Regards,
> >>> Michalis
> >>>
> >>> czw., 26 mar 2020 o 06:30 John Carlson <yottzumm at gmail.com>
> napisał(a):
> >>> >
> >>> > DEF/USE is how multiparent nodes are achieved, but all DEF and USE
> with the same value are the same node, except for a few special cases.
> >>> >
> >>> > This is what one reason why HTML DOM is a poor choice...the nodes
> have only one parent.
> >>> >
> >>> > Or I’m still battling windmills?
> >>> >
> >>> > John
> >>> >
> >>> > On Wed, Mar 25, 2020 at 10:16 PM GPU Group <gpugroup at gmail.com>
> wrote:
> >>> >>
> >>> >> double defining:
> >>> >> - this stymied me too, until I realized the DEF/USE are just for
> the parser, and its the sequence that counts although different for
> different browsers.
> >>> >> - if you redef 3 times, then USE, what will you get?
> >>> >> - that depends on the web3d browser, with some sticking to the
> first DEF, some the last DEF.
> >>> >>
> >>> >> On Wed, Mar 25, 2020 at 9:01 PM John Carlson <yottzumm at gmail.com>
> wrote:
> >>> >>>
> >>> >>> If one DEF specified a shape and another DEF with the same value
> with a different shape, wouldn't the 2 browsers show different shapes if
> they picked different DEFs?
> >>> >>>
> >>> >>> I don't think double DEFs should be allowed within the same
> namespace.
> >>> >>>
> >>> >>> John
> >>> >>>
> >>> >>> On Wed, Mar 25, 2020 at 9:12 PM GPU Group <gpugroup at gmail.com>
> wrote:
> >>> >>>>
> >>> >>>> Chisel? "it was simply put in the public domain by Trapezium when
> they folded many years ago. They didn¹t specify any license" - Louka
> >>> >>>> http://dug9.users.sourceforge.net/web3d/temp/chisel-src.zip
> >>> >>>> But I suspect double-deffing isn't illegal. I think I've been
> through it, and different browsers honored the first or last definition.
> >>> >>>> -Doug
> >>> >>>>
> >>> >>>> On Wed, Mar 25, 2020 at 7:43 PM John Carlson <yottzumm at gmail.com>
> wrote:
> >>> >>>>>
> >>> >>>>> That is, more than one DEF with the same value.
> >>> >>>>>
> >>> >>>>> I realize that separate PROTOs may have the same DEF due to
> namespaces.   Unfortunately writing a Unix script to find this takes
> massive brain power.
> >>> >>>>>
> >>> >>>>> John
> >>> >>>>>
> >>> >>>>> On Wed, Mar 25, 2020 at 8:37 PM John Carlson <yottzumm at gmail.com>
> wrote:
> >>> >>>>>>
> >>> >>>>>> I’m not particular looking for a vrml parser unless it catches
> double use of a DEF.
> >>> >>>>>>
> >>> >>>>>> Thanks,
> >>> >>>>>>
> >>> >>>>>> John
> >>> >>>>>>
> >>> >>>>>> I’m thinking my next project might be a VRML validator if there
> isn’t one handy?  Anyone?
> >>> >>>>>>
> >>> >>>>>> I know I can translate VRML to XML.
> >>> >>>>>>
> >>> >>>>>> John
> >>> >>>>>>
> >>> >>>>>> On Wed, Mar 25, 2020 at 3:38 PM John Carlson <
> yottzumm at gmail.com> wrote:
> >>> >>>>>>>
> >>> >>>>>>> Say, where is a VRML Validator? !!!!
> >>> >>>>>>>
> >>> >>>>>>> On Wed, Mar 25, 2020 at 3:33 PM John Carlson <
> yottzumm at gmail.com> wrote:
> >>> >>>>>>>>
> >>> >>>>>>>> I will download X3D-Edit and do some validation on the files,
> or go to the validation site @ savage
> >>> >>>>>
> >>> >>>>> _______________________________________________
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> >>> >>>>
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> >>> >
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