[osg-users] Fwd: CallBack issue

Ulrich Hertlein u.hertlein at sandbox.de
Fri Mar 27 21:04:33 PDT 2009


Hi Sajjad,

On 28/3/09 12:01 PM, ami guru wrote:
> With callbacks we dynamically modify the node during the update
> traversal.So any node that has already gone through some affine
> transformation will be replaced in the call backs, but not concatenated.
>
> On  the other hand if we specify any affine trnasformation after calling
> the callback, the last transformation will be concatenated to the one
> that have been assigned durng callbacks.
>
> And that happens to any type of dynamic transformation , not only with
> the affine one.

I'm not quite sure I follow you.  What you're describing has nothing to do with the update 
traversal as such.

You're setting the transformation matrix of a certain node.  Naturally this overwrites 
whatever was set before.

If you need a certain transformation (e.g. a scale) to be preserved then either put it in 
a parent or child MatrixTransform or include it in the calculated matrix.  Or decompose 
the existing matrix and re-assemble it with the modified values.

Cheers,
/ulrich



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