[x3d-public] Thoughts for x3d.py str() calls

Mon Oct 16 22:36:35 PDT 2023

The python "scenegraph" is being constructed on the fly.  There's really no
scenegraph, we are exporting XML and VRML from Blender.  The exported XML
and VRML is not acceptable to X3D viewer.  Have you ever seen an exported
scenegraph?

On Mon, Oct 16, 2023 at 10:08 PM Joe D Williams <joedwil at earthlink.net>
wrote:

> > Q3. Do you acknowledge x3d.py controls the order fields of a node are
> exported?
>
>
>
> Is that it? .py may control, but  you control .py.
>
> It is the author's call what to put out there. It is the  syntax rules
> that define whether it is right or not.
>
> If the.py code is out of order then the browser that reads it should issue
> warning.
>
> I don't see what the problem is. Maybe the .py code result needs to be
> checked by a real browser. The .py  code should not take the step of
> reordering code, unless it is also doing a validation in coordination with
> the author.
>
> But I'm not the slightest bit familiar with the .py code. What is it
> supposed to do?
>
> Joe
>
> -----Original Message-----
> From: John Carlson <yottzumm at gmail.com>
> Sent: Oct 16, 2023 7:59 PM
> To: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
> Cc: GPU Group <gpugroup at gmail.com>, Joe D Williams <joedwil at earthlink.net>,
> Peitso, Loren (CIV) <lepeitso at nps.edu>, X3D Graphics public mailing list <
> x3d-public at web3d.org>
> Subject: Re: Thoughts for x3d.py str() calls
>
>
> Joe, read bullet point 3 carefully, then tell me where all the extra DEFs
> you added to Doug’s example went.
>
> On Mon, Oct 16, 2023 at 8:15 PM Brutzman, Donald (Don) (CIV) <
> brutzman at nps.edu> wrote:
>
>> John, if you are asking whether duplicate DEF names are allowed in a
>> single X3D model, the answer is no.
>>
>>
>>
>>
>>
>>    - *X3D 4.0 Architecture, clause 4 Concepts, 4.4.3 DEF/USE semantics*
>>    - Node DEF names are limited in scope to a single X3D file, prototype
>>    definition, or string submitted to either CreateX3DFromString,
>>    CreateX3DFromStream, or CreateX3DFromURL X3D browser service (as specified
>>    in ISO/IEC 19775-2).
>>    - The USE statement does not create a copy of the node identified by
>>    a DEF name. Instead, the same node is inserted into the scene graph a
>>    second time, resulting in the node having multiple parents (see 4.3.5
>>    Transformation hierarchy, for restrictions on self-referential nodes).
>>    - Node names shall be unique in the context within which the
>>    associated DEF name occurs.
>>    -
>>    https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-IS.proof/Part01/concepts.html
>>
>>
>>
>>
>>
>>
>>
>> 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:* John Carlson <yottzumm at gmail.com>
>> *Sent:* Monday, October 16, 2023 5:42 PM
>> *To:* Joe D Williams <joedwil at earthlink.net>
>> *Cc:* Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>; GPU Group <
>> gpugroup at gmail.com>; Peitso, Loren (CIV) <lepeitso at nps.edu>; X3D
>> Graphics public mailing list <x3d-public at web3d.org>
>> *Subject:* Re: Thoughts for x3d.py str() calls
>>
>>
>>
>> Here’s a python example from Doug:
>>
>>
>>
>>
>>
>> trans = Transform(DEF='C')
>>
>> grpb.children.append(trans)
>>
>> grpa.children.append(trans)
>>
>>
>>
>> Is the author doing the wrong thing?
>>
>>
>>
>> John
>>
>>
>>
>> On Mon, Oct 16, 2023 at 7:37 PM John Carlson <yottzumm at gmail.com> wrote:
>>
>> If we keep a reference around to place in both skin coordinate and
>> skinCoord, will x3d.py be smart enough to output DEF in the first case and
>> USE in the second case, or will it just output whatever DEF or USE is
>> currently stored for the node?  Will it gladly print out both USE and DEF
>> plus all the fields along with USE and DEF?  A simple python example would
>> use a a reference more than once.  I don’t have that yet, but it should be
>> easy to create one.
>>
>>
>>
>> No, I don’t want to override the str function, because my new function
>> will use it.
>>
>>
>>
>> On Mon, Oct 16, 2023 at 5:32 PM Joe D Williams <joedwil at earthlink.net>
>> wrote:
>>
>> I don't know if this helps, but just from memory, every loader I have
>> ever seen that deep into will assign a unique def if a DEFable field does
>> not have a DEF. I think a DEF always helps the runtime. The SAI can
>> discover the assignment if you need it.
>>
>> Joe
>>
>>
>>
>> -----Original Message-----
>> From: GPU Group <gpugroup at gmail.com>
>> Sent: Oct 16, 2023 2:36 PM
>> To: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
>> Cc: John Carlson <yottzumm at gmail.com>, Joe D Williams <
>> joedwil at earthlink.net>, Peitso, Loren (CIV) <lepeitso at nps.edu>, X3D
>> Graphics public mailing list <x3d-public at web3d.org>
>> Subject: Re: Thoughts for x3d.py str() calls
>>
>>
>>
>> Don,
>>
>> Q1. Do you acknowledge x3d.py makes no attempt to conjugate DEF and USE
>> of the same name?
>>
>> Q2. Do you acknowledge some nodes in x3d can have multiple fields using
>> the same node?
>>
>> Q3. Do you acknowledge x3d.py controls the order fields of a node are
>> exported?
>>
>> Q4. Do you acknowledge there may be use-cases when a script using x3d.py
>> will instance DEF and USE x3d.py nodes of the same name in a different
>> order than x3d.py may export?
>>
>> In HAnimHumanoid 2 fields take the same Coordinate node: a) .coordinate
>> b) .skin (in descendent nodes)
>>
>> The blender exporter traverses the blender scenegraph in a systematic
>> order convenient to that script. The first time it encounters the
>> Coordinate node it instances an x3d.py Coordinate node with a DEF. The
>> subsequent times it encounters the same node it instances an x3d.py node
>> with a USE of the same name.
>>
>> x3d.py exports the HAnimHumanoid.coordinate field before .skin. That's a
>> different order than the user script visits blender nodes.
>>
>> That 2-field-same-node scenario may not occur frequently in web3d, or a
>> using-script may be lucky in its case to instance the DEF and USE in the
>> same order as x3d.py happens to export. So many successful Examples don't
>> help this case.
>>
>> -Doug
>>
>>
>>
>>
>>
>> On Mon, Oct 16, 2023 at 2:47 PM Brutzman, Donald (Don) (CIV) <
>> brutzman at nps.edu> wrote:
>>
>> The x3d.py makes no effort to correct author errors.  That is up to the
>> author.  Trying to “fix” things further can lead to further problems and a
>> corrupted model.
>>
>>
>>
>> There are a great many models in X3D Examples with DEF and USE which run
>> properly in unit tests.
>>
>>
>>
>> There are several diagnostics built in for reporting errors.  Have you
>> tested your erroneous scene to see what you get?  If a further error
>> diagnostic is needed, we can add it to the  X3DPSAIL TODO list.  If you
>> write a python method to do that, we can test it further and possibly
>> integrate it.
>>
>>
>>
>>    - X3D Python Scene Access Interface Library (X3DPSAIL), TODO
>>    - https://www.web3d.org/x3d/stylesheets/python/python.html#TODO
>>
>>
>>
>> If a correct model is getting exported into another form incorrectly,
>> then we can diagnose and fix the conversion.  As ever, use-case examples of
>> such errors are essential to continuing progress.
>>
>>
>>
>> Thanks for all efforts with X3D Python.
>>
>>
>>
>> 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:* GPU Group <gpugroup at gmail.com>
>> *Sent:* Monday, October 16, 2023 9:49 AM
>> *To:* John Carlson <yottzumm at gmail.com>
>> *Cc:* Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>; Joe D Williams <
>> joedwil at earthlink.net>; Peitso, Loren (CIV) <lepeitso at nps.edu>; X3D
>> Graphics public mailing list <x3d-public at web3d.org>
>> *Subject:* Re: Thoughts for x3d.py str() calls
>>
>>
>>
>> correction first output is
>>
>>   <Scene>
>>
>>     <Group DEF='A'>
>>
>>       <Transform DEF='C'/>
>>
>>     </Group>
>>
>>     <Group DEF='B'>
>>
>>       <Transform DEF='C'/>
>>
>>     </Group>
>>
>>
>>
>> On Mon, Oct 16, 2023 at 10:32 AM GPU Group <gpugroup at gmail.com> wrote:
>>
>> That may relate to the DEF USE issue with X3D.py:
>>
>> x x3d.py makes no effort to conjugate DEF and USE and properly order DEF
>> before USE in its export stream
>>
>> - not a common problem unless a node has 2 fields that take the same node
>> (directly SF or indirectly in MFNode descendent field)
>>
>> x it's a problem with HAnimHumanoid which has coordinate and skin fields,
>> which typically involve the same Coordinate node
>>
>> - tinkering can be done in the blender exporter, to do a USE before a
>> DEF,  but with inconvenience and messy code
>>
>> If a call can be made in x3d.py before exporting a DEF or USE, then that
>> function can be over-ridden to take responsibility for DEF USE conjugation
>> and correct output ordering something like this:
>>
>> node = getDefOrUse(node, node.DEF, node.USE)
>>
>> and for the x3d.py default it would just return the same element (or
>> node), and overrides can do something more sophisticated.
>>
>>
>>
>> more..
>>
>> DEF USE NON-CONJUGATION IN X3D.PY
>>
>> test_def.py
>>
>> x3d = X3D()
>>
>> scene = Scene()
>>
>> x3d.Scene = scene
>>
>> grpa = Group(DEF='A')
>>
>> grpb = Group(DEF='B')
>>
>> scene.children.append(grpa)
>>
>> scene.children.append(grpb)
>>
>> trans = Transform(DEF='C')
>>
>> grpb.children.append(trans)
>>
>> grpa.children.append(trans)
>>
>> blob = x3d.XML()
>>
>> fp = open("dump.x3d","w+")
>>
>> fp.write(blob)
>>
>> fp.close()
>>
>>
>>
>> output:
>>
>> <?xml version="1.0" encoding="UTF-8"?>
>>
>> <!DOCTYPE X3D PUBLIC "ISO//Web3D//DTD X3D 4.0//EN" "
>> https://www.web3d.org/specifications/x3d-4.0.dtd">
>>
>> <X3D profile='Full' version='4.0' xmlns:xsd='
>> http://www.w3.org/2001/XMLSchema-instance
>> <https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.w3.org%2F2001%2FXMLSchema-instance&data=05%7C01%7Cbrutzman%40nps.edu%7C89d7f7485cd84f8b903608dbcea9d716%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C638331001111259651%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=Wuo4vUbsIurLvuOtQluXwClFaf7DbgnvyoTw8vvWPGo%3D&reserved=0>'
>> xsd:noNamespaceSchemaLocation='
>> https://www.web3d.org/specifications/x3d-4.0.xsd'>
>>
>>   <Scene>
>>
>>     <Group DEF='A'>
>>
>>       <Transform USE='C'/>
>>
>>     </Group>
>>
>>     <Group DEF='B'>
>>
>>       <Transform DEF='C'/>
>>
>>     </Group>
>>
>>   </Scene>
>>
>> </X3D>
>>
>>
>>
>> test_def_use.py
>>
>> from x3d import *
>>
>>
>>
>> x3d = X3D()
>>
>> scene = Scene()
>>
>> x3d.Scene = scene
>>
>> grpa = Group(DEF='A')
>>
>> grpb = Group(DEF='B')
>>
>> scene.children.append(grpa)
>>
>> scene.children.append(grpb)
>>
>> trans = Transform(DEF='C')
>>
>> grpb.children.append(trans)
>>
>> grpa.children.append(trans)
>>
>> blob = x3d.XML()
>>
>> fp = open("dump.x3d","w+")
>>
>> fp.write(blob)
>>
>> fp.close()
>>
>>
>>
>> output:
>>
>> <?xml version="1.0" encoding="UTF-8"?>
>>
>> <!DOCTYPE X3D PUBLIC "ISO//Web3D//DTD X3D 4.0//EN" "
>> https://www.web3d.org/specifications/x3d-4.0.dtd">
>>
>> <X3D profile='Full' version='4.0' xmlns:xsd='
>> http://www.w3.org/2001/XMLSchema-instance
>> <https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.w3.org%2F2001%2FXMLSchema-instance&data=05%7C01%7Cbrutzman%40nps.edu%7C89d7f7485cd84f8b903608dbcea9d716%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C638331001111259651%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=Wuo4vUbsIurLvuOtQluXwClFaf7DbgnvyoTw8vvWPGo%3D&reserved=0>'
>> xsd:noNamespaceSchemaLocation='
>> https://www.web3d.org/specifications/x3d-4.0.xsd'>
>>
>>   <Scene>
>>
>>     <Group DEF='A'>
>>
>>       <Transform USE='C'/>
>>
>>     </Group>
>>
>>     <Group DEF='B'>
>>
>>       <Transform DEF='C'/>
>>
>>     </Group>
>>
>>   </Scene>
>>
>> </X3D>
>>
>>
>>
>>
>>
>>
>>
>> On Mon, Oct 16, 2023 at 10:09 AM GPU Group <gpugroup at gmail.com> wrote:
>>
>> It seems possible to override functions in python, if there are just a
>> few to override.
>>
>> And one suggestion for x3d.py imperfections is to apply fixes at runtime
>> in some initialization function.
>>
>> - that assumes/requires just a few target functions, not 480 functions
>> that need to be repaired
>>
>> - so for some fixes it may be helpful to change the upstream x3d.py to
>> call a function that can be easily replaced.
>>
>> -Doug
>>
>> Example:
>>
>> file myclass.py
>>
>> class Wonky:
>>
>>   def __init__(self):
>>
>>     self.color = "Red"
>>
>>   def func1(self, color :str) -> bool:
>>
>>     if color == self.color:
>>
>>       return True
>>
>>     return False
>>
>>
>>
>> file override.py
>>
>> from myclass import *
>>
>>
>>
>> mc = Wonky()
>>
>> print("match with Blue? "+str(mc.func1("Blue")))
>>
>>
>>
>> def func2(self, color: str) -> bool:
>>
>>   if self.color != color:
>>
>>     return True
>>
>>   return False
>>
>> Wonky.func1 = func2 # <<<<<<<<<<<< OVERRIDE
>>
>> print("don't match with Blue? "+str(mc.func1("Blue")))
>>
>>
>>
>> output:
>>
>> match with Blue? False
>>
>> don't match with Blue? True
>>
>> -Doug
>>
>>
>>
>> On Mon, Oct 16, 2023 at 9:55 AM John Carlson <yottzumm at gmail.com> wrote:
>>
>> Instead of calling str() to print out a value, call a function that does
>> precision floating point formatting on floats according to a user’s
>> wishes.  If the value is a list, call the function recursively with a list
>> comprehension, otherwise, call str.
>>
>>
>>
>> I think this is doable by mere humans.
>>
>>
>>
>> Thanks,
>>
>>
>>
>> John
>>
>>
>>
>>
>
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