outline

Justification

• Not enough interpolators
• variable conversion
• complex interactions

Not enough interpolators built into VRML

• float to string?
• translation to rotation?
• Y rotation to Z rotation?
• Circle interpolator?

More complex interactions

• conecting switches
• H2oComp
• Light switch demo

Elements of the script node

• eventIns
• eventOuts
• fields
• url

eventIn

• Name convention: set_something
• Syntax: eventIn type name
• Example: eventIn SFBool set_status
• Receives values, triggers event
• function with same name as eventIn
• value passed as a parameter to function

eventOut

• Name convention: something_changed
• Syntax: eventOut type name
• Example: eventOut SFBool status_changed
• most scripts will assign value to eventOut
• eventOut looks like a variable to script
• the function's output is eventOut(s)

field

• Name convention: any name
• Syntax: field type name
• Example: field SFInt32 count
• Example: field SFNode output USE textbox

URL

• points to script
• javaScript .js file
• java .class file
• "javascript: multiline quote

Using inline JS scripts

• Multiline quote
• use ' or \" inside script
• easiest way for simple scripts
• Our preferred technique

Organization of a script

• Function corresponding to each eventIn
• function will have two parameters,
  • value
  • timestamp

Example:

• 
  eventIn SFBool value_changed
  url " javascript:
    function value_changed(val, time){
      //code goes here
    } // end function
  "