Introducing Script Use

Motivation

Many actions are too complex for animation nodes:

• Computed animation paths (eg. gravity)
• Algorithmic shapes (eg. fractals)
• Collaborative environments (eg. games)

You can create new sensors, interpolators, etc., using program scripts written in:

• JavaScript - easy-to-learn language
• ECMAScript - same as JavaScript

Syntax: Script

A Script node selects a program script to run:

• url - choice of program script

XML Encoding

<Script DEF='Bouncer'>
<![CDATA[ecmascript:
...
]]>
</Script>

<!-- or -->

<Script DEF='Bouncer'
    url='"bouncer.js"'/>

Classic VRML Encoding

DEF Bouncer Script {
  url "ecmascript: ..."
  #or...
  url "bouncer.js"
}

Defining the program script interface

A Script node also declares the program script interface:

• initializeOnly, inputOnly, outputOnly, inputOutput - inputs and outputs
  • Each has a name and data type
  • Fields have an initial value

XML Encoding

<Script DEF='Bouncer'>
  <field accessType='initializeOnly' type='SFFloat' name='bounceHeight' value='3'/>
  <field accessType='inputOnly' type='SFFloat' name='set_fraction'/>
  <field accessType='outputOnly' type='SFVec3f' name='value_changed'/>
  <field accessType='inputOutput' type='SFBool' name='enabled' value='true'/>
</Script>

Classic VRML Encoding

DEF Bouncer Script {
  initializeOnly  SFFloat bounceHeight 3.0
  inputOnly       SFFloat set_fraction
  outputOnly      SFVec3f value_changed
  inputOutput     SFBool  enabled TRUE
}

A sample using a program script

XML Encoding

<TimeSensor DEF='Clock' ... />

<Transform DEF='Ball' ... />

<Script DEF='Bouncer'>
  <field accessType='initializeOnly' type='SFFloat' name='bounceHeight' value='3'/>
  <field accessType='inputOnly' type='SFFloat' name='set_fraction'/>
  <field accessType='outputOnly' type='SFVec3f' name='value_changed'/>
  <field accessType='inputOutput' type='SFBool' name='enabled' value='true'/>
<![CDATA[ecmascript:
...
]]>
</Script>

<ROUTE fromNode='Clock' fromField='fraction_changed' toNode='Bouncer' toField='set_fraction'/>
<ROUTE fromNode='Bouncer' fromField='value_changed' toNode='Ball' toField='set_translation'/>

Classic VRML Encoding

DEF Clock TimeSensor { ... }

DEF Ball Transform { ... }

DEF Bouncer Script {
  initializeOnly  SFFloat bounceHeight 3.0
  inputOnly       SFFloat set_fraction
  outputOnly      SFVec3f value_changed
  inputOutput     SFBool  enabled TRUE
  url "ecmascript: ..."
}

ROUTE Clock.fraction_changed TO Bouncer.set_fraction
ROUTE Bouncer.value_changed  TO Ball.set_translation

Summary

The Script node selects a program script, specified by a URL.

Program scripts have field and event interface declarations, each with:

• A data type
• A name
• An initial value (fields only)