Thanks a lot!


-----Message d'origine-----
De : [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] De la part de Robert Osfield
Envoyé : lundi 11 décembre 2006 15:26
À : osg users
Objet : Re: [osg-users] Modif of a geometry

HI Antoine,

On 12/11/06, Antoine Rennuit <[EMAIL PROTECTED]> wrote:
> I have created an osg::Geometry that I display with no problem. At the
> moment I change the color of this Geometry creating a new array of colors
> and calling setColorArray(myNewColorsArray) on the Geometry each time I
> need. But I wondered if the memory was well managed: is the previous array
> of colors (set at the previous call to setColorArray) deleted
automatically
> with my method?

The OSG uses display lists by default, so if you update the data you
need to call geometry->dirtyDisplayList() to ensure that it knows to
update its display lists.  Alternatively just turn off display lists
via geometry->setUseDisplayList(false), particularly if you plan to
update the geometry regularly as display list generation is a slow.

> And last, I have a frame orientation 1 with respect to frame 0, given by
> quaternion 0q1. Now I want to rotate this orientation 1 around its own x
> axis (a rotation of frame 1 around x1) - the rotation around the x axis of
> whatever frame being given by qx. What I have done in most other 3D
> packages, and the theory gives 0q1 * qx for my new orientation (* being
the
> quaternion multiplication). What I had to do in osg to obtain the desired
> final orientation was the commuted multiplication qx * 0q1. Any idea why?

The OSG uses the post multiple form of :

   v' = v * M

Rather than

  v' = M * v

Which you are possibly used to.

Robert.
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