[osg-users] Animating vertices in a Geode

Muller, L.Y.L. L.Y.L.Muller at uva.nl
Mon Mar 23 13:44:56 PDT 2009

Hi Cedric,

hmm for some reason the post of Guy wasn't added to the right thread in the maillist ( http://lists.openscenegraph.org/pipermail/osg-users-openscenegraph.org/2009-March/025337.html )
I tried out his suggestion and got something like a self-deleting callback working (Demo file is attached). I just need to figure out how to measure the time between the callback calls. For now it just increments the 'time' value with a fixed number.
It would ofcourse be nicer if I could use an exciting class that handles the scheduling/timeline.

About your request, I do not know how to create a stacktrace here with Visual Studio 2005, but that would require the debug libraries of OSG right? I could try stepping through the code with the debugger later this week and see where it locks up/crashes.
I also noticed that there are some other issues with the (animation?) demos. After building the OSG 2.9.1 package (svn), I tried out a few of the animation demos. Running the demos is not a problem, but if you try to close them, it usually result in a crash. I'm not sure if its the osgAnimation part thats causing it or the viewer.

Kind regards,
- Laurence 

P.S.: Sorry about the previous reply, I made a mistake while attaching the file... ;\

-----Original Message-----
From: Cedric Pinson [mailto:mornifle at plopbyte.net]
Sent: Mon 3/23/2009 4:27 PM
To: OpenSceneGraph Users
Subject: Re: [osg-users] Animating vertices in a Geode
Hi Laurence,
Before i dig into can you give the stacktrace to have an idea where it 
crashes ?


Laurence Muller wrote:
> Hi Cedric,
> I tried to create a simple project based on the 'osganimationmorph' 
> demo as Robert Osfield suggested.
> Instead of loading the geometries from a *.osg file, I define two new 
> geometries (both quads but on a different position). These geometries 
> are added as a drawable to the MorphGeometry.
> However, for some reason OSG doesn't allows me to swap the old geom0 
> and geom1 geometry objects with the ones I create. The application 
> crashes when you try to run it.
> Any suggestions?
> Kind regards,
> - Laurence
> Cedric Pinson wrote:
>> <div class="moz-text-flowed" style="font-family: -moz-fixed">Hi 
>> Laurence,
>> You can easily do it with morphgeometry:
>> - define two geometry with morphgeometry
>> - use an custom update callback that use an ease motion to control 
>> the ratio of geometry to use
>> Would be great to make an example with it, it will help others users.
>> Cheers,
>> Cedric
>> Laurence Muller wrote:
>>> 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/osgAnimation 
>>> 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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>>> osg-users mailing list
>>> osg-users at lists.openscenegraph.org
>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org 
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+33 (0) 6 63 20 03 56  Cedric Pinson mailto:mornifle at plopbyte.net http://www.plopbyte.net

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