[x3d-public] second round of X3D JSON conversion support using X3dToJson.xslt

[Don Brutzman]

We had a really great hour-long discussion on the X3D call today.  Thank you Cecile, John, Roy, Leonard, Dick, Anita and Nicholas for participating.

I heard a number of really interesting points:

a. Priorities include round trip support and programmer usefulness
b.comments support remains possible but needs work, despite omission in JSON spec.
c. following VRML97/ClassicVRML encoding patterns can really help
d. handling child nodes has three choices:  always an JSON array, JSON array or JSON object depending on what is present, or "deep knowledge" of X3D node types (e.g. containerField field names)
e. handling of USE field
f. excluding or including default attribute values - both may have merit
g. can someone compare with Collada JSON and glTF approaches?
h. D3.js integration is an excellent test case
i. Javascript function to write X3D JSON back out to .x3d is useful, also enables round-trip testing
j. Script/field and Prototype/field representations are interesting, perhaps not of everyday interest but might become really useful for X3DOM
k. Others please?

Meanwhile last night saw a few more improvements in the X3dToJson.xslt stylesheet:
- integration of jsonlint into build suite regression tests, providing comprehensive error checking of JSON X3D for thousands of example scenes
- alternative handling of field, fieldValue similar to contained nodes in X3D, improved but still testing

Further improvements to follow based on the above.  I an really encouraged and think that a simple useful JSON X3D is possible, but only through continued group collaboration and compare/contrast/implement/evaluate.

We will include x3dom list on major summary points, and issues that can be of direct benefit, but will conduct most design discussions on x3d-public list.

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 http://faculty.nps.edu/brutzman