VRML 2.0 Scene Graph Structure

1. VRML 2.0 Scene Graph Structure Nodes Group Transformation Shape

2. Shape Node:Contained Nodes Shape appearance Appearance geometry Box Cone Cylinder Sphere Extrusion material textureTransform texture Image, Movie PixelTexture Texture Transform Material Indexed Face Set Point Set Indexed Line Set Elevation Grid Text color coord color coord fontStyle texCoord normal coord color color texCoord normal Texture Coordinate FontStyle Coordinate Color Normal

3. Text Node DefinitionfontStyle Node Definition Text { exposedField MFString string[] exposedField SFNode fontStyle NULL exposedField MFFloat length [] exposedField SFFloat maxExtent 0.0 } FontStyle { field MFString family “SERIF” field SFBool horizontal TRUE field MFString justify “BEGIN” field SFSring language ““ field SFFloat size 1.0 field SFFloat spacing 1.0 field SFString style “PLAIN” field SFBool topToBottom TRUE field SFBool leftToRight TRUE }

4. Appearance & Material Nodes Appearance { exposedField SFNode material NULL exposedField SFNode texture NULL exposedField SFNode textureTransform NULL } Material { exposedField SFFloat ambientIntensity 0.2 exposedField SFColor diffuseColor 0.8 0.8 0.8 exposedField SFColor emissiveColor 0 0 0 exposedField SFFloat shininess 0.2 exposedField SFColor specularColor 0 0 0 exposedField SFFloat transparency 0 }

5. Texture Node Definitions ImageTexture { exposedField MFString url [] field SFBool repeatS TRUE feild SFBool repeatT TRUE } PixelTexture { exposedField SFImage image 0 0 0 field SFBool repeatS TRUE feild SFBool repeatT TRUE }

6. Texture Node Definitions,Continued MovieTexture { exposedField SFBool loop FALSE exposedField SFFloat speed 1 exposedField SFTime startTime 0 exposedField SFTime stopTime 0 exposedField MFString url [] field SFBool repeatS TRUE field SFBool repeatT TRUE eventOut SFFloat duration_changed eventOut SFBool isActive }

7. Lighting in VRML 2.0Directional Light Source DirectionalLight { exposedField SFFloat ambientIntensity 0 exposedField SFColor color 1 1 1 exposedField SFVec3f direction 0 0 -1 exposedField SFFloat intensity 1 exposedField SFBool on TRUE } Directional lights are “scoped” to illuminate only objects in their group.

8. Lighting in VRML 2.0Point Light Sources PointLight { exposedField SFFloat ambientIntensity 0 exposedField SFVec3f attenuation 1 0 0 exposedField SFColor color 1 1 1 exposedField SFFloat intensity 1 exposedField SFVec3f location 0 0 0 exposedField SFBool on TRUE exposedField SFFloat radius 100 } Scoping for the PointLight is given by the radius field, beyond which no objects are illuminated

9. Lighting in VRML 2.0Spotlights SpotLight { exposedField SFFloat ambientIntensity 0 exposedField SFVec3f attenuation 1 0 0 exposedField SFFloat beamwidth 1.570796 exposedField SFColor color 1 1 1 exposedField SFFloat cutOffAngle 0.785398 exposedField SFVec3f direction 0 0 -1 exposedField SFFloat intensity 1 exposedField SFVec3f location 0 0 0 exposedField SFBool on TRUE exposedField SFFloat radius 100 }

10. Transform Node Definition Transform { enventIn MFNode addChildren eventIn MFNode removeChildren exposedField SFVec3f center 0 0 0 exposedField MFNode children [] exposedField SFRotation rotation 0 0 1 0 exposedField SFVec3f scale 1 1 1 exposedField SFRotation scaleOrientation 0 0 1 0 exposedField SFVec3f translation 0 0 0 field SFVec3f bboxCenter 0 0 0 field SFVec3f bboxSize -1 -1 -1 } Order of application: T(translation) • T(rotation) • T(scale) {children}

11. GroupNode Definition Transform { enventIn MFNode addChildren eventIn MFNode removeChildren exposedField MFNode children [] field SFVec3f bboxCenter 0 0 0 field SFVec3f bboxSize -1 -1 -1 }

12. Viewing in VRML 2.0 Viewpoint { eventIn SFBool set_bind exposedField SFFloat fieldOfView 0.785396 exposedField SFBool jump TRUE exposedField SFRotation orientation 0 0 1 0 exposedField SFVec3f position 0 0 10 field SFString description ““ eventOut SFTime bindTime eventOut SFBool isBound }

13. Sound in VRML 2.0Definition of Sound Node Sound { exposedField SFVec3f direction 0 0 1 exposedField SFFloat intensity 1 exposedField SFVec3f location 0 0 0 exposedField SFFloat maxBack 10 exposedField SFFloat maxFront 10 exposedField SFFloat minBack 1 exposedField SFFloat minFront 1 exposedField SFFloat priority 0 exposedField SFNode source NULL field SFBool spatialize TRUE }

14. Sound in VRML2.0Definition of AudioClip Node AudioClip { exposedField SFString description ““ exposedField SFBool loop FALSE exposedField SFFloat pitch 1.0 exposedField SFTime startTime 0 exposedField SFTime stopTime 0 exposedField MFString url [] eventOut duration_changed eventOut isActive }

15. Spatial Sound Pattern in VRML 2.0 Constant intensity location Linear Attenuation direction minBack minFront maxFront maxBack

16. Internode Communication:Events eventOut Node A Node B Node C eventIn Connection by a ROUTE

17. field Private node member exposedField Public node member eventIn Event received by node eventOut Event sent by node set_<fieldNname> Event received by node <fieldName>_changed Event sent by node Internode CommunicationNode Field Classes Type and value of events correspond to type and value of node fields.

18. Internode CommunicationRoute Syntax DEF T1 Transform { . . . } DEF T2 Transform { . . . } DEF T3 Transform { . . . } . . . ROUTE T1.translation_changed TO T2.set_translation ROUTE T2.translation_changed TO T3.set_translation T1 T2 T3 translation translation translation

19. Event Generators:Touch Sensor = Shapes Sensed

20. Event Generators:Touch Sensor TouchSensor { exposedField SFBool enabled TRUE eventOut SFVec3f hitNormal_changed eventOut SFVec3f hitPoint_changed eventOut SFVec2f hitTexCoord_changed eventOut SFBool isActive eventOut SFBool isOver eventOut SFTime touchTime }

21. Touch SensorExample Group { children [ DEF TS TouchSensor { } Shape { appearance Appearance { material Material { diffuseColor 0 0.5 0 } } geometry Sphere {} } DEF Highlight DirectionalLight { color 1 0 0 on FALSE } DEF ActiveLight DirectionalLight { color 0 0 1 on FALSE } ] ROUTE TS.isOver TO Highlight.set_on ROUTE TS.isActive TO ActiveLight.set_on }

22. Touch SensorExample Group { children [ DEF TS TouchSensor { } Shape { appearance Appearance { material Material { diffuseColor 0 0.5 0 } } geometry Sphere {} } Sound { maxBack 1000 maxFront 1000 source DEF Audio AudioClip { url “horse.wav” } } ] ROUTE TS.touchTime TO Audio.startTime }

23. Adding Behavior to Objects TimeSensor Interpolator General Node Generates time vary- ing scalar in range [0,1] Maps [0,1] to field data type values. [0,1] ScalarInterpolator PositionInterpolator OrientationInterpolator CoordinateInterpolator ColorInterpolator

24. Time Sensor TimeSensor { exposedField SFTime cycleInterval 1 exposedField SFBool enabled TRUE exposedField SFBool loop FALSE exposedField SFTime startTime 0 exposedField SFTime stopTime 0 eventOut SFTime cycleTime eventOut SFFloat fraction_changed eventOut SFBool isActive eventOut SFTime time } loop=TRUE loop=FALSE startTime cycleInterval stopTime

25. Position Interpolator PositionInterpolator { eventIn SFFloat set_fraction exposedField MFFloat key [] exposedField MFVec3f keyValue [] eventOut SFVec3f value_changed } y x Input: [ 0 1 ] z

26. Position AnimationExample Def T Transform { translation 0 5 0 children [ Shape { geometry Cone {} appearance Appearance { material Material { diffuseColor 1 0 0 } } } ] } Def P PositionInterpolator { key [0, 0.5, 1] keyValue [ 0 0 0, 4 0 0, 0 0 0] } Def TS TimeSensor { stopTime -1 loop TRUE } ROUTE TS.fraction_changed TO P.set_fraction ROUTE P.value_changed TO T.set_translation

27. Java 3D:Class Hierarchy

28. Java 3D:Viewing Classes Contains information about physical screen Contains most of view state Locates a view within scene 3D version of Abstract Windowing Toolkit

29. Java 3D:Sample Code to Build Scene Graph Shape3D myShape1 = new Shape3D(myGeometry1, myAppearance1); Shape3D myShape2 = new Shape3D(myGeometry2, myAppearance2); BranchGroup myBranch = new BranchGroup(); myBranch.addChild(myShape1); myBranch.addChild(myShape2); myBranch.compile(); VirtualUniverse myUniverse = new VirtualUniverse(); Locale myLocale = new Locale(myUniverse); myLocale.addBranchGraph(myBranch);

30. Java 3D:Scene Graph Built

31. Java 3D;Node Class Hierarchy

32. Java 3D “Hello Universe” Program public class HelloUniverse extends Applet { public BranchGroup createSceneGraph() { // Create the root of the branch graph BranchGroup objRoot = new BranchGroup(); // Create the TransformGroup node and initialize it to the // identity. Enable the TRANSFORM_WRITE capability so that // our behavior code can modify it at run time. Add it to // the root of the subgraph. TransformGroup objTrans = new TransformGroup(); objTrans.setCapability( TransformGroup.ALLOW_TRANSFORM_WRITE); objRoot.addChild(objTrans); // Create a simple Shape3D node; add it to the scene graph. objTrans.addChild(new ColorCube(0.4)); // Create a new Behavior object that will perform the // desired operation on the specified transform and add // it into the scene graph.

33. Java 3D“Hello Universe” Program, contd. Transform3D yAxis = new Transform3D(); Alpha rotationAlpha = new Alpha(-1, 4000); RotationInterpolator rotator = new RotationInterpolator( rotationAlpha, objTrans, yAxis, 0.0f, (float) Math.PI*2.0f); BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0); rotator.setSchedulingBounds(bounds); objRoot.addChild(rotator); // Have Java 3D perform optimizations on this scene graph. objRoot.compile(); return objRoot; } public HelloUniverse() { <set layout of applet, construct canvas3d, add canvas3d> // Create the scene; attach it to the virtual universe BranchGroup scene = createSceneGraph(); SimpleUniverse u = new SimpleUniverse(canvas3d); u.getViewingPlatform().setNominalViewingTransform(); u.addBranchGraph(scene); } }