The TrackballManipulator does not support a zoom function. Rather, the right mouse button pans the Camera along the view direction vector. This is a different effect from zoom, which is a change to the field of view without changing the Camera position. With an orthographic Projection matrix, moving the Camera along the view direction vector obviously has no visual effect; the Camera does not have a distance in an orthographic Projection.
So the short answer is that the TrackballManipulator doesn't support the zoom function that you require. Your options? Create a new Manipulator that supports zoom by changing the field of view. To do this correctly, you need to support both changing the field of view in a perspective Projection matrix, as well as changing the left/right/bottom/top values for an orthographic Projection. Hope that helps, -Paul > > Hello Everyone, > I'm trying to use a TrackballManipulator in conjunction with > an orthographic camera (i.e., I'm using > osg::Camera::setProjectionMatrixAsOrtho()). The problem is > that model scaling (with right mouse button) does not work. > This is because TrackballManipulator achieves a scaling > effect by changing the distance between the camera and the > model. Unfortunately, this doesn't have the desired effect > when using an orthographic camera. The model does not change > size at all in the display window. Then, when I zoom far > enough, I start to see parts disappear due to clipping issues. > > Is there a way for me to use TrackballManipulator (with an > ortho camera) more effectively such that I don't see this > behavior? If not, is there another built-in manipulator that > would work better for my purposes? If not, what are your > other recommendations? > > Thank you very much! > Rob > > PS - I'm using OSG v 2.2 but, from a code inspection, (I > think) I've determined that the behavior is the same in version 2.6. > _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
