<ramp>

Description

A ramp node is a signal generator. The signal it generates is either a classical sawtooth ( /|/|/| ) or a triangle ( /\/\/\ ), depending on the pingpong value. The shape of the signal can be smoothened using dampening parameters. The signal 'fires' once or loops.

The signal can be used by behavior nodes, either by triggering them periodically, or by feeding a value into them. Behaviors can be either referenced using the behavior attribute, or inlined as a child of the ramp.

Syntax

<tour>
  <scene>
    <panoelement id="nodeID" ...\>
    ...

    <ramp id="rampID" behavior="someBehavior" 
      value1="0" value2="1" duration="5" loop="true" active="false" />
    ...
  </scene>
  ...

</tour>

Attributes

• id

  Unique id to reference the ramp by.

• active

  Turns the signal on or off.
  Values: true or false, defaults to false

• value1

  Specifies one of the two values to interpolate to and from.
  Values: numeric, defaults to 0

• value2

  Specifies one of the two values to interpolate to and from.
  Values: numeric, defaults to value1 + 1

• value

  Specifies the value when the ramp is initialised.
  Values: numeric, between value1 and value2

• minvalue

  Specifies a minimal value for the ramp to generate. If both minvalue and maxvalue are specified, the computed value will be wrapped between these two limits.
  Values: numeric, between value1 and value2

• maxvalue

  Specifies a maximum value for the ramp to generate. If both minvalue and maxvalue are specified, the computed value will be wrapped between these two limits.
  Values: numeric, between value1 and value2

• duration

  Controls the time in seconds it should take to reach value2 from value1 or vice versa.
  Ignored if maxstep or stepincrease are specified.
  Values: >0, defaults to 1

• maxstep

  Controls the maximum step on each iteration for value to reach its destination value (either value1 or value2, depending on direction), effectively setting the maximum steepness of the signal as an alternative to the duration.
  Values: >0

• stepincrease

  Dampens the step on each iteration. The step value is increased on each iteration until it reaches maxstep (if specified) or until step needs to decrease to smoothly reach its destination.
  Values: >0

• direction

  Specifies the (initial) direction of the signal.
  Values: 1 (towards value 2) or -1 (towards value1)

• pingpong

  Specifies whether the signal has a sawtooth or triangle shape.
  Values: true (triangle, /\/\/\/\) or false (sawtooth, /|/|/|/|), defaults to false

• loop

  Specifies whether the signal continues after value reaches either value1 or value2.
  Values: 1 or higher, ot 'true'. If set to 'true', sounds loops indefinately. Defaults to false.

• interrupt

  Specifies whether the signal can be interrupted by pressing a mousebutton, a key and/or moving the mouse. If the ramp is interrupted, value will be reset to the value opposite direction (ie: if direction=1, value will be reset to value1).
  Values: "hover", "press", "key" (or a comma-delimitted combination such as "press,key"

Events

• start

  Fires when value is set to true.

• stop

  Fires when value reaches its target value and loop = false.

• loop

  Fires when value reaches its target value and loop = true.

• change

  Fired when value has changed while the ramp was active (on each iteration).

• interrupt

  Fired when the ramp is interrupted (see interrupt attribute).

Children

• behavior

History

• 18-Dec-07: Added minvalue, maxvalue
• 22-Nov-07: Added loop=n, fixed code example
• 14-Oct-05: Move towards more complete documentation
• 20-Oct-04: Changed name to ramp
• 03-Aug-04: Initial version