[x3d-public] X3D JSON encoding: refactoring, simplifying handling of #comment and #ROUTE

[Don Brutzman]

Argh.  Trying again.

Roy spotted an error:

On 12/19/2015 1:09 PM, Don Brutzman wrote:
> =========================================
> *alternative JSON encoding*
> =========================================
> "-children":[
>    { "#comment":"Shape begin"},
>    { "Shape":
>      {
>        "#comment":[
>          "Sphere begin",
>          "Sphere complete, Appearance begin",
>          "Appearance complete"
>        ],

Corrected excerpt:

=========================================
*alternative JSON encoding*
=========================================
"-children":[
   { "#comment":"Shape begin"},
   { "Shape":
     {
       "-children":[
         { "#comment":"Sphere begin"},
         { "#comment":"Sphere complete, Appearance begin"},
         { "#comment":"Appearance complete"}
       ],

This is a good snippet because it shows benefits and drawbacks:

++ Comment is always a standalone object
++ Reduced loss of ordering when a parent node has -children fields
-  Use of -children inside Shape etc. is a partial misnomer; the comment is not a children field, but it is a child
+  This improves on prior encoding, but still does not preserve order perfectly with Shape and other non-grouping nodes.

The prior alternative JSON did have these comments within the Shape correctly included - again attached.

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
-------------- next part --------------
{ "X3D": {
    "@profile":"Immersive",
    "@version":3.3,
    "@xsd:noNamespaceSchemaLocation":"http://www.web3d.org/specifications/x3d-3.3.xsd",
    "head": {
        "meta": [
          {
            "@name":"title",
            "@content":"HelloWorldCommented.x3d"
          },
          {
            "@name":"description",
            "@content":"Numerous comments added to simple X3D scene example for testing JSON encoding alternatives."
          },
          {
            "@name":"created",
            "@content":"19 December 2015"
          },
          {
            "@name":"modified",
            "@content":"19 December 2015"
          },
          {
            "@name":"creator",
            "@content":"Don Brutzman"
          },
          {
            "@name":"reference",
            "@content":"HelloWorldCommentedOriginalEncoding.json"
          },
          {
            "@name":"reference",
            "@content":"HelloWorldCommentedAlternativeEncoding.json"
          },
          {
            "@name":"identifier",
            "@content":"http://X3dGraphics.com/examples/X3dForAdvancedModeling/HelloWorldScenes/HelloWorldCommented.x3d"
          },
          {
            "@name":"license",
            "@content":"http://www.web3d.org/x3d/content/examples/license.html"
          },
          {
            "@name":"generator",
            "@content":"X3D-Edit 3.3, https://savage.nps.edu/X3D-Edit"
          }
        ]
    },
    "Scene": {
        "-children":[
          { "#comment":"Example scene to illustrate comments interspersed among X3D nodes and fields (XML elements and attributes)"},
          { "#comment":"WorldInfo begin"},
          { "WorldInfo":
            {
              "@title":"Hello world!"
            }
          },
          { "#comment":"WorldInfo complete, Group begin"},
          { "Group":
            {
              "-children":[
                { "#comment":"Viewpoint begin"},
                { "Viewpoint":
                  {
                    "@DEF":"ViewUpClose",
                    "@centerOfRotation":[0,-1,0],
                    "@description":"Hello world!",
                    "@position":[0,-1,7]
                  }
                },
                { "#comment":"Viewpoint complete, Transform begin"},
                { "Transform":
                  {
                    "@rotation":[0,1,0,3],
                    "-children":[
                      { "#comment":"Shape begin"},
                      { "Shape":
                        {
                          "-children":[
                            { "#comment":"Sphere begin"},
                            { "#comment":"Sphere complete, Appearance begin"},
                            { "#comment":"Appearance complete"}
                          ],
                          "-geometry":[
                            { "Sphere":
                              {
                              }
                            }
                          ],
                          "-appearance":[
                            { "Appearance":
                              {
                                "-children":[
                                 { "#comment":"Material begin"},
                                 { "#comment":"Material complete, ImageTexture begin"},
                                 { "#comment":"ImageTexture complete"}
                                ],
                                "-material":[
                                  { "Material":
                                    {
                                      "@DEF":"MaterialLightBlue",
                                      "@diffuseColor":[0.1,0.5,1]
                                    }
                                  }
                                ],
                                "-texture":[
                                  { "ImageTexture":
                                    {
                                      "@DEF":"ImageCloudlessEarth",
                                      "@url":["earth-topo.png","earth-topo.jpg","earth-topo-small.gif","http://www.web3d.org/x3d/content/examples/Basic/earth-topo.png","http://www.web3d.org/x3d/content/examples/Basic/earth-topo.jpg","http://www.web3d.org/x3d/content/examples/Basic/earth-topo-small.gif"]
                                    }
                                  }
                                ]
                              }
                            }
                          ]
                        }
                      },
                      { "#comment":"Shape complete"}
                    ]
                  }
                },
                { "#comment":"Transform complete, Transform begin"},
                { "Transform":
                  {
                    "@translation":[0,-2,0],
                    "-children":[
                      { "#comment":"Shape begin"},
                      { "Shape":
                        {
                          "-children":[
                            { "#comment":"Text begin"},
                            { "#comment":"Text complete, Appearance begin"},
                            { "#comment":"Appearance complete"}
                          ],
                          "-geometry":[
                            { "Text":
                              {
                                "@DEF":"TextMessage",
                                "@string":["Hello","world!"],
                                "-children":[
                                  { "#comment":"FontStyle begin"},
                                  { "#comment":"FontStyle complete"}
                                ],
                                "-fontStyle":[
                                  { "FontStyle":
                                    {
                                      "@justify":["MIDDLE","MIDDLE"]
                                    }
                                  }
                                ]
                              }
                            }
                          ],
                          "-appearance":[
                            { "Appearance":
                              {
                                "-children":[
                                  { "#comment":"Material begin"},
                                  { "#comment":"Material complete"}
                                ],
                                "-material":[
                                  { "Material":
                                    {
                                      "@USE":"MaterialLightBlue"
                                    }
                                  }
                                ]
                              }
                            }
                          ]
                        }
                      },
                      { "#comment":"Shape complete"}
                    ]
                  }
                },
                { "#comment":"Transform complete"}
              ]
            }
          },
          { "#comment":"Group complete"}
        ]
    }
  }
}