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Please note that This document is no longer up-to-date. (Though it is still valid.)
Please note that a more up-to-date document is available. A paper has been published that
covers the topic in a more comprehensive way. It proposes besides the Damper nodes also the
group of Chaser nodes that are usefull in cases where the Dampers fail.
To the paper: Linear Filters - Animating Objects in a Flexible and Pleasing Way
If you decide to continue reading this document, please keep in mind that now some fields on
the Damper nodes have
changed their name.
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The Position2fDamper node is for the
SFVec2f data type what the
PositionDamper is for the
SFVec3f data type. It allows to smoothly
animate 2D coordinates.
EXTERNPROTO Position2fDamper
[
eventIn SFVec2f set_input
field SFVec2f initial_input # 0 0
eventOut SFVec2f output_changed
field SFVec2f initial_output # 0 0
eventIn SFVec2f set_output
exposedField SFFloat tau # 1
field SFInt32 order # 1
field SFFloat eps # .001
eventOut SFBool isActive
eventOut SFBool isLoaded
]
"Dampers.wrl#Position2fDamper"
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Explanation of the fields:
See the page about all Damper PROTOs.
It contains a general description of the fields to which there is nothing to
add to here.
The Demo:
The page provides a TouchSensor
connected with a square. If you move the mouse over that square
the texture coordinates are sent through a
Position2fDamper to
a Script node that
converts it from SFVec2f
to SFVec3f and drives the
position of a little sphere. The
tau field of the
Position2fDamper node
is set to 0.2 and the order
field is set to 3. Thus the sphere smoothly follows the movements
of the mouse pointer.
Surrounding the square there are four buttons. If you click on
one of them the position of the button is sent to the
set_output eventIn
of the Position2fDamper.
This makes the sphere jump to that button and move back to the
position the mouse has left the square.
Please note that while the mouse cursor is outside the square
no texture coordinates are sent from the
TouchSensor to the
Position2fDamper.
If you download the
Test_Position2fDamper.wrl and
Dampers.wrl files
to your local hard disk you can modify it in order to
see the effects of setting
set_output without
setting set_input,
setting set_input without
setting set_output or
setting both to the same value as well as the effects of varying
tau and
order fields.
__.-.__
end of document
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