Difference between revisions of "X3D and HTML5 Summary"

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== Simple [[X3D and HTML5 examples]] ==
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== Simple X3D and HTML5 examples ==
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Detailed example source is provided on the [[X3D and HTML5 examples]] page.
 
* X3D scene as external reference (Anchor link)
 
* X3D scene as external reference (Anchor link)
 
   HTML source:  Here is my <a href='[http://www.web3d.org/x3d/content/examples/HelloWorld.x3d HelloWorld.x3d]' title='Link to new X3D document'>[http://www.web3d.org/x3d/content/examples/HelloWorld.x3d HelloWorld example]</a> in X3D.
 
   HTML source:  Here is my <a href='[http://www.web3d.org/x3d/content/examples/HelloWorld.x3d HelloWorld.x3d]' title='Link to new X3D document'>[http://www.web3d.org/x3d/content/examples/HelloWorld.x3d HelloWorld example]</a> in X3D.

Revision as of 15:35, 6 November 2009

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


Family of X3D Specifications

  • X3D Abstract Specification describes basic functionality of how X3D works
  • Three file formats are available: XML (.x3d), ClassicVRML (x3dv), and Compressed Binary Encoding (.x3db)
  • High-performance Application Programming Interfaces (APIs) are defined for Ecmascript-264 (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


Web3D Consortium has formal liaisons and working partnerships with other key organizations


Relationships between 3D 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, perhaps WebGL or O3D)
  • Render layers are low-level software libraries that expose the functionality of graphics hardware (e.g. OpenGL and DirectX)
  • Numerous other 3D technologies exist at each these other layers, often in the form of codebases
  • 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 functionally consistent standardized high-performance APIs
  • 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 (.x3d, .x3dv, .x3db)
  • Document Object Model (DOM) is also legal (X3D is XML after all) but historically has been infrequently used because of low performance


Differences with underlying render layers

  • OpenGL, DirectX, others are used as render layers for output of X3D player which parses .x3d XML files and draws them
  • Unlikely that all browsers will implement the same render layer (OpenGL ≠ DirectX)
  • A Canvas3D layer might be helpful to unify calls to the underlying render layer - but how will it evolve over time?
  • Not clear that Web authors are clamoring for ability to program low-level OpenGl (or similar) source code in Javascript, such models are not interoperable or composable
  • X3D avoids these problems as a declarative scene-graph language available in XML


Simple X3D and HTML5 examples

Detailed example source is provided on the X3D and HTML5 examples page.

  • X3D scene as external reference (Anchor link)
  HTML source:  Here is my <a href='HelloWorld.x3d' title='Link to new X3D document'>HelloWorld example</a> in X3D.
  • X3D embedded in object tag
  HTML Object Tag for X3D shows how to place X3D objects within an HTML page
  • HTML5 with embedded X3D as mixed-namespace document
  X3Dom demonstration

Lessons learned from years developing the FreeWrl X3D player

  • Experience: FreeWRL was originally interpreted Perl with specialized "C" functions. Hoped that hardware would improve faster than size of models; that was not the case.
  • Interpreted was not the way to go, rewritten in C for performance
  • Differing OpenGL capabilities: X3D Browsers can handle these, so older models can run efficiently on new hardware (write once, run anytime; even VRML1 models from NASA run fast now)
  • X3D models are not tied to specific hardware, can run over OpenGL-ES, OpenGL-3.2, DirectX11, older standards like OpenGL-1.0...
  • OpenGL requires significant programming skills. Don't know why the average web author would want to code in OpenGL.
  • What does FreeWRL require from Web browser or window? An OpenGL Context (i.e. a number); mouse and keyboard events, window size events, that's about it.


Action items for X3D and HTML5

  • Ensure proper X3D references in HTML5 specifications - what happened, what happens next?
  • How to allow X3D scene to either reserve screen space or float over the page? Presumably CSS, X3D elements include the class attribute
  • X3D version 3.3 draft is considering SVG and HTML as source for image textures; how to pass events?
  • X3D compression will likely evolve to use Efficient XML Interchange (EXI)
  • Web Accessibility is a future interest
  • Continue to document correct integration and best practices for X3D and HTML5


Conclusions

  • X3D Graphics is a natural fit for HTML5
  • We want to maximize capabilities and deployment
  • Further collaboration welcome