Hi Gianluca, The AutoTransform adjusts it's internal settings based on the eye position, which is acquired during the cull traversal. Have a look at the implementation of the AutoTransform::accept() to see what is going. If you want to find the value of the AutoTransform for a given camera position prior to the cull traversal then you'll need to do a dummy cull traversal by creating your own cull visitor.
Robert. On Mon, Aug 10, 2009 at 11:42 AM, Gianluca Natale<[email protected]> wrote: > Hi All. > I have this problem, with OSG 2.8.0. > > > > In my scenegraph there is some object attached as a child of an > Autotransform matrix > (I need to keep its size constant on the screen, wherever is the camera). > > I have also to fit the model in the screen, using the global bounding sphere > of the model. > I’ve seen that the bounding sphere is computed during the rendering > traversal. > > And that the bounding sphere of “auto-transformed” objects changes as the > camera position > changes, while the bounding sphere of the other objects is constant. This is > what I expected, since > the size on the screen must be constant. > > So, I thought that I can compute the global bounding sphere of my model by > multiple iterative redraws, > > until the global bounding sphere at step n is almost the same as that at > step n-1. > And it works. > > > > Is there a way to update the bounding sphere of autotransformed object > without redrawing? > I mean, I would need to show directly the model fit in the screen, without > showing the user all the single steps. > Or, at least, may I avoid the swap of back and front buffers at the end of > redraw? In this way I could > make the back and front buffers be swapped only at the end of fit. > > > > Thanks in advance > > Gianluca Natale > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
