1. H3D API Training Part 2.1: X3D

2. Outline  Scene graphs  X3D – XML syntax  X3D components overview

3. Scene Graph Group Transform Shape Box Shape Sphere“gold” children appearance geometry

4. Scene Graph  The scene graph is a directed graph of nodes used to define and manage applications  Hierarchical structure – children/parent. Each node affects its children.

5. What is a Node? ◦ A container for fields: ◦ Manages fields  Allocation, deallocation of fields  Initialisation of fields  Manages internal (and external) routes ◦ Reusable modules of functionality ◦ Simplify application development

6. Nodes

7. X3D  ISO standard for 3D content and interaction  Backwards compatible with VRML  www.web3d.org

8. X3D - XML  “XML encoding” of X3D  Similar in appearance to HTML (technically a subset of XML)  Basic structure: ◦ Header ◦ Statements (scene graph nodes, routes)

9. Example

10. XML  Objects encoded begin with a “<name” and end with either ◦ “/>” for single entities ◦ “ ” for compound entities

11. Comments  Comments are enclosed within

12. X3D – DEF/USE

13. X3D – DEF/USE example  Reference an existing DEFined Node with the USE attribute  Useful to avoid data duplication / redundancy ◦ Especially with appearances ◦ Any mesh geometry that is identical

14. X3D - ROUTE  Dependencies between field are set up with routes:

15. Example DEF/USE/ROUTE

16. X3D - containerField  Indicates the default field that a node should be assigned to ◦ e.g. “child” for Group, Transform, Shape ◦ “appearance” for Appearance ◦ “geometry” for IndexedFaceSet, Sphere  containerField hidden from most X3D and H3D use, but necessary to know about

17. X3D Components

18. Grouping Component  Group ◦ Basic grouping.  Transform ◦ Specifies coordinate system transformation.  Switch ◦ Choose one of many children.

19. Geometry Component  Shape  Appearance  Geometry ◦ Box ◦ Cone ◦ Sphere ◦ IndexedFaceSet ◦ etc

20. Texturing Component  ImageTexture ◦ MultiTexture ◦ PixelTexture ◦ (MovieTexture)  TextureTransform  TextureCoordinate

21. Interpolator Component  Useful for basic animations: ◦ ColorInterpolator ◦ CoordinateInterpolator ◦ NormalInterpolator ◦ OrientationInterpolator ◦ PositionInterpolator

22. Text Component  Text  FontStyle

23. Lighting Component  DirectionalLight  PointLight  SpotLight

24. Other Components  Time  RigidBodyPhysics  Rendering  Sound  Device Sensors  Navigation  Programmable shaders  Particle system

25. X3D Abstract Nodes  X3D specification defines abstract nodes; ◦ Cannot be instantiated / used ◦ Contain common functionality used in certain types of nodes ◦ Nodes inherit from abstract nodes

26. X3D Abstract Nodes  All X3D abstract nodes begin with “x3d” ◦ X3DNode ◦ X3DChildNode ◦ X3DGroupingNode ◦ X3DGeometryNode ◦ X3DLightNode ◦ etc

27. Interface objects  X3D specifies a number of abstract interfaces.  Specifies some functionality that a node should implement.  Examples: X3DBoundedObject X3DUrlObject H3DDisplayListObject

28. H3DLoad and H3DViewer  Settings via H3DLoadSettings program  H3DLoad – console  H3DViewer – window application ◦ Settings for changing different options on the fly.