X3D and HTML5 Summary

Status: these are draft slides for the X3D and HTML5 effort that will be provided to the Technical Plenary Week (TPAC) 2009.

• Family of X3D Specifications;
  • X3D Abstract Specification describes basic functionality
  • Three file formats are available: XML (.x3d), ClassicVRML (x3dv), and Compressed Binary Encoding (.x3db)
  • High-performance Application Programming Interfaces (APIs) are defined for Ecmascript (Javascript) and Java

• X3D Strengths
  • Non-profit Web3D Consortium maintains and extends X3D via working groups
  • Set of International Standards certified over 12-year period by multiple national bodies in ISO
  • Multiple implementations are available (open and commercial source)
  • Numerous resources available online, including specifications themselves
  • Third-generation 3D graphics language that extends predecessor Virtual Reality Modeling Language (VRML97)
  • Long-time W3C member and contributor
  • Formal liaisons and working partnerships with International Organization for Standardization (ISO), Open Geospatial Consortium (OGC), The Khronos Group, and Digital Imaging and Communications in Medicine (DICOM)

• Relationships between scene graphs, APIs and render layers;
  • Scene graphs are high-level declarative models about how geometry is constructed, colored and animated; these can be expressed as an XML tree
  • APIs are mid-level libraries for programmers to create imperative source code about geometry and animation (various proprietary codebases, O3D, perhaps WebGL)
  • Render layers are low-level software libraries that expose the functionality of graphics hardware (e.g. OpenGL, DirectX)
  • Numerous other 3D technologies exist at each of the other layers
  • The X3D Specifications include both declarative models and strongly typed APIs

• Similarities between MathML, SVG, and X3D;
  • MathML describes mathematical expressions and then renders a presentation of them
  • Scalable Vector Graphics (SVG) describes and presents renderings of 2D shapes, with optional animation and interaction
  • Extensible 3D (X3D) describes and presents renderings of 3D shapes, with optional animation and interaction
  • All three languages are formally specified and have well-developed XML encodings
  • Authors want to use these languages for multimedia content in HTML pages

• X3D scene graph APIs
  • X3D Scene Access Interface (SAI) provides a consistent standardized high-performance API
  • X3D SAI has Ecmascript and Java bindings, other programming languages can be added
  • X3D SAI is functionally equivalent and has same expressive power as file formats
  • Document Object Model (DOM) is also legal (X3D is XML after all) but infrequently used because of low performance

• Simple X3D + HTML5 examples;
  • X3D scene as external reference (Anchor link)
  • X3D embedded in object tag
  • HTML5 with embedded X3D as mixed-namespace document
  • Forthcoming InstantReality X3DOM javascript demo: html5+x3d with event passing connections
  • (Can we structure our non-scripted examples to correspond to MathML and SVG examples?)
  • (We likely need multiple examples corresponding to DOM/SAI approaches)

• Recommendation actions for HTML5 Recommendation
  • Ensure proper X3D references in HTML5 specifications
  • Document correct integration and best practices
  • What about XHTML?
  • Other recommendations?

• Joe - draft Example #1, served as application/xhtml+xml

      (how current integration looks like via object model then to html5)

      <za href='aScene.x3d' title='A new X3D document window'>Enter My Scene</a>
      (html anchor link; z is artifact).
      In this case the host browser uses whatever it has access to in order to create a new window browsing context for the target .x3d resource. 

• Joe - draft Example #2, embedd using object element. <object name='x3d' type='model/x3d+xml' allow-same-origin allow-scripts>

         <param name='src' value='aScene.x3d'>
        <ztable>...</table>
      </object>
      Opens nested browsing context in parent block element.
      Fallback to html table. (s z is artifact). 
      Connections with DOM via event listeners (DOM<=>SAI). 
      Set of negotiated <param> pairs: initialization and runtime.

• Joe - draft Example #2, served as application/xhtml+xml

      <?xml version="1.0" encoding="utf-8" ?>
      <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
      <html xmlns="http://www.w3.org/1999/xhtml">
        <head>
          <style type=text/css'>
            x3d:X3D { height:200px;width:200px; }
          </style>
        </head>
        <body>
          <x3d:x3d xmlns:x3d="http://www.web3d.org/specifications/x3d-3.2.xsd">
            <x3d:Scene>
              <x3d:Shape>
                <x3d:Box x3d:size="4 4 4" />
              </x3d:Shape>
              <x3d:Shape>
                <x3d:Text x3d:string='"This is X3D Text"' />
              <x3d:/Shape>
          </x3d:Scene>
        </x3d:x3d>
      </body>
      </html>

• Joe - draft Example #3, served as text/html

      <!DOCTYPE html>
      <html>
        <head>
          <style type=text/css'>
            X3D { height:200px;width:200px; }
          </style>
        </head>
        <body>
          <X3D>
            <Scene>
              <Shape>
                <Box size="4 4 4" />
              </Shape>
              <Shape>
                <Text string='"This is X3D Text"' />
              </Shape>
            </Scene>
          </X3D>
        </body>
      </html>