VRML Basic Syntax

1
VRML Basic Syntax

• Lee, Chan Su
• chansu_at_caip.rutgers.edu

2
File Syntax and Structure(I)

• Component of VRML file

• head

• prototypesPROTO, EXTERNPROTO

• nodes, field, script

• DEF/USE statements

• Route statements

Floops.wrl
Floops.txt
3
File Syntax and Structure(II)

• Syntax Basics
• illegal character
• First Character - 0-9 , . \
  0x-0x20
• All other Character , . \ 0x-0x20

• Reserved Keywords DEF, PROTO,..

4
Head

• Head
• VRML V2.0 ltencoding typegt comment ltline
  terminatorgt
• VRML V2.0 utf8

utf8Universal Character Set Transform Format
Comment to the end of the line is comment
5
Node(I)

• Node
• analogous to object , or function

• If you make a scene with node, it makes object in
  the virtual environment

DEF ltnamegt ltnodeTypegt ltbodygt
6
Node(II)

• Nodes Body consists of any number of

• field statements,

• IS statements,

• ROUTE statements,

• PROTO statements or EXTERNPROTO statements

in any order
7
Node(III)

• Nodes are commonly supplied to fields of other
  nodes.

Node1 fieldName Node2 Node2
fields set here
8
Node(IV)

• Group NodeAnchor, Billboard, Collision, Group,
  Inline, LOD(Level of Detail), Switch, Transform

• nodes that can contain and manage other nodes

9
Node(V)
Group children Nodename1 node1
., Nodename2 node2 .,
...
10
Field(I)

• 3 Kinds of Field Type

• field A private member of the nodeno access to
  and from other node

• eventIn An event received by the Nodeother node
  can set this field

• eventOut An event sent by the nodeother nodes
  can receive values form this field, but not set
  them

11
Field(II)

• Field Type-exposedField

• A public member of the nodeother nodes are free
  to set this field and also receive them

• eventInfieldeventOut

• in general set_nodeName for eventIn

• nodeName_changed for eventOut

12
Field(III)

• Data Type

• SF-/MF

• -Bool/ -Int32/ -Float/ -Color/ -Node/ -String/
  -Time/ -Vec2f/ -Vec3f/ -IMage

SFFloat/ MFFloat SFString, MFVec3f
13
Field(IV)

• class_specifier data_type field_name default
  range
• field SFFloat radius
  1 0 to ?

• Exception of name in exposedField
• Boolean eventOuts isNodeName
• SFTime exitTime, startTime

14
DEF/USE statement

• A node given a name using DEF keyword may later
  be referenced by name with USE or ROUTE
  statements

• The USE statement does not create a copy of the
  node

DEF ltnamegt ltnodeTypegt ltbodygt
DEF Red Material diffuseColor 1 0 0
USE ltnamegt
15
Example of Node Definition
Transform eventIn MFNode
addChildren eventIn MFNode
removeChildren exposedField SFVec3f center
0 0 0 (-,) exposedField MFNode
children exposedField
SFRotation rotation 0 0 1 0
-1,1,(-,) exposedField SFVec3f scale
1 1 1 (0,) exposedField SFRotation
scaleOrientation 0 0 1 0 -1,1,(-,)
exposedField SFVec3f translation 0 0 0
(-,) field SFVec3f bboxCenter
0 0 0 (-,) field SFVec3f
bboxSize -1 -1 -1 (0,) or -1,-1,-1
16
Coordinate System

• Cartesian, right-handed, 3D coordinate System

• Standard Units

• Viewing Model-Viewport
• define specific location of viewer

17
Building Predefined Shapes(I)

• Shape Node Syntax

Shape exposedField SFNode appearance NULL
exposedField SFNode geometry NULL
18
Building Predefined Shapes(II)

• Appearance Node Syntax

Appearance exposedField SFNode material
NULL exposedField SFNode texture
NULL exposedField SFNode textureTransform
NULL
19
Building Predefined Shapes(III)

• Material Node Syntax

Material exposedField SFFloat
ambientIntensity 0.2 0,1
exposedField SFColor diffuseColor 0.8 0.8
0.8 0,1 exposedField SFColor emissiveColor
0 0 0 0,1 exposedField SFFloat
shininess 0.2 0,1
exposedField SFColor specularColor 0 0 0
0,1 exposedField SFFloat transparency
0 0,1
20
Building Predefined Shapes(IV)

• Primitive Geometry node

• Box, Cone, Cylinder, Sphere

• Syntax for Box node

Box field SFVec3f size 2 2 2
(0, )
21
Building Predefined Shapes(V)

• Syntax for Cone

Cone field SFFloat bottomRadius 1
(0,) field SFFloat height 2
(0,) field SFBool side
TRUE field SFBool bottom TRUE
22
Building Predefined Shapes(VI)

• Syntax for Cylinder

Cylinder field SFBool bottom TRUE
field SFFloat height 2 (0,)
field SFFloat radius 1 (0,)
field SFBool side TRUE field SFBool
top TRUE
23
Example of VRML File(I)

• Simple VRML File
• Cone.txt
• Cone.wrl

• If you change the field, the scene will be changed

24
Route/Sensors

• Lee, Chan Su
• chansu_at_caip.rutgers.edu

25
Event Route(I)

• Event
• allow objects to have and express
• more realistic and life like virtual experience

26
Event Route(II)

• Route
• The connection between the node generating the
  event and the node receiving the event

• Routes are not nodes, but merely a syntactic
  construct to field naming conventions

Type Matching In eventIn and eventOut
27
Event Route(III)
ROUTE NodeName.eventOutName TO NodeName.eventInNam
e
28
Sensor Nodes(I)

• Change of the State of an Input Device

• Anchor

• TouchSensor

• CylinderSensor

• PlaneSensor

• SphereSensor

29
Sensor Nodes(II)

• Change of Viewer or Object

• ProximitySensor

• VisibilitySensor

• Collision Group

• Change in Time

• TimeSensor

30
Execution Model
ROUTE A.touchTime TO B.toggleNow ROUTE
A.touchTime TO C.set_startTime ROUTE
B.toggle_changed TO C.set_enabled
Event Cascade, Fan-in and Fan-out
31
Sensing Viewer Actions(I)

• 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
32
Sensing Viewer Actions(I)

• 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
33
Sensing Viewer Actions(II)

• PlaneSensor

PlaneSensor exposedField SFBool autoOffset
TRUE exposedField SFBool enabled
TRUE exposedField SFVec2f maxPosition
-1 -1 (-,) exposedField SFVec2f
minPosition 0 0 (-,)
exposedField SFVec3f offset 0 0 0
(-,) eventOut SFBool isActive
eventOut SFVec3f trackPoint_changed
eventOut SFVec3f translation_changed
34
Sensing Viewer Actions(III)

• SphereSensor

SphereSensor exposedField SFBool
autoOffset TRUE exposedField SFBool
enabled TRUE exposedField SFRotation
offset 0 1 0 0 -1,1,(-,)
eventOut SFBool isActive eventOut
SFRotation rotation_changed eventOut
SFVec3f trackPoint_changed
35
Sensing Viewer Actions(IV)

• CylinderSensor

CylinderSensor exposedField SFBool
autoOffset TRUE exposedField SFFloat
diskAngle 0.262 (0,/2) exposedField
SFBool enabled TRUE exposedField SFFloat
maxAngle -1 -2,2 exposedField
SFFloat minAngle 0 -2,2
exposedField SFFloat offset 0
(-,) eventOut SFBool isActive
eventOut SFRotation rotation_changed
eventOut SFVec3f trackPoint_changed
36
Sensor Route Example
route_test.txt
route_test.wrl
ROUTE Shape1Sensor.rotation_changed TO
Shape1.set_rotation ROUTE Shape2Sensor.rotation_ch
anged TO Shape2.set_rotation
37
Program Project I

• interaction in VRML
• using Sensor
• using ROUTE
• using primitive geometry
• changing according to user action

• Email to each person