[osg-users] Animating vertices in a Geode

Guy guy at dvp.co.il
Sun Mar 22 00:44:49 PDT 2009


I think you just need to use update callback for your geometry, in this
callback you set the vertex array with the new locations and then call
dirty() to ensure the update of the display list.

Guy.

Hi,

In the application I am working on, I am trying to create a smooth 
(transition) animation on the vertices inside an object.

Example:
I have included an illustration to make my problem a bit more clear. The

current scene contains one geode with a geometry attached.
The geometry is filled with 7 quads (4 vertices per quad) and is 
illustrated as red dots in the picture. (The 'edges' are stored in a 
separate geode)

The application allows users to select a specific layout (radial, force 
based, etc) for the quads. In the current implementation this change 
happens immediately.
(It updates the vertex array with new values and uses the dirty() call 
on the vertex array).

On the OSG wiki page I found some information about animating objects in

the scene graph.
http://www.openscenegraph.org/projects/osg/wiki/Community/NodeKits/osgAn
imation
http://www.robertpenner.com/easing/easing_demo.html

However, it seems like this will only work on geode level (by modifying 
the Matrix or PositionAttitudeTransformation).
Another problem with this method is that it seems that you need to 
create a predefined animation.

In my case the new position of a vertex will depend on the current 
position (and the animation only needs to be used once).

Question:
- Is there a way to use the osgAnimation functions on the vertex array 
and is it possible to use it with the transition methods from the 
EaseMotion demo?

Kind regards,
- Laurence

------------------------------------------
Laurence Muller
Website/Blog/Portfolio:
http://www.multigesture.net/




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