[osg-users] Trackball and view question

Poirier, Guillaume Guillaume.Poirier at nrc-cnrc.gc.ca
Wed Sep 19 06:35:01 PDT 2007


Thanks Robert and Christophe,

I guess my question is once I have a trackball manipulator on my main camera and
read the camera's eye and center in the post draw callback, what is the transformation
needed to convert those eye and center vectors to the vectors I would get if there was
no trackball manipulator on the main camera ? Hope this is a bit clearer on what
I want to do...

Bill

-----Original Message-----
From: osg-users-bounces at lists.openscenegraph.org on behalf of Robert Osfield
Sent: Tue 9/18/2007 11:28 AM
To: OpenSceneGraph Users
Subject: Re: [osg-users] Trackball and view question
 
Hi Bill,

The camera manipulators role is to modifying the view matrix so I'm a
bit perplexed that you are suprised by this.

Also please considering move from SimpleViewer up to osgViewer::Viewer
working as an embedded viewer in 2.x rather than using SimpleViewer as
it only existed for a short while and has been totally superseded.

Robert.

On 9/18/07, Poirier, Guillaume <Guillaume.Poirier at nrc-cnrc.gc.ca> wrote:
>
>
>
>
> Hello everyone,
>
>  I am using a SimpleViewer. I set up a post draw callback on its main
> camera. In it
>  I read the camera eye, center, and up vectors. Initially, this give me (0,
> 0, 0),
>  (0, 0, -1), and (0, 1, 0) respectively. This is what I expect and it gives
> me a
>  particular view of my scene.
>
>  Now I add a trackball manipulator to the main camera and set up the view
> similar
>  to what I had previously. When I read back the data it is quite different.
> I would have
>  expected the same camera position / orientation than before since what I
> see is
>  similar. Unless the trackball affects the model position / orientation and
> not just
>  the view ? How can I use a trackball and read back in the post draw
> callback the
>  values I want ?
>
>
>  sincerely,
>
>
>  Bill
> _______________________________________________
> osg-users mailing list
> osg-users at lists.openscenegraph.org
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>
>
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