> Presumably because getViewMatrixAsLookAt() doesn't do any > magic, it just takes the Y axis (in this case) of the matrix > as the view vector. This vector will be normalised (otherwise > the camera would do funky things), so all it can do is > subtract this unit vector from the eye position.
The name 'center' is probably a misnomer here, and certainly has nothing to do with the orbital center of the manipulator. getViewMatrixAsLookAt has its roots in the gluLookAt function. The second parameter is a point that your eye is looking at. Of course there are several points that your eye is looking at, all along the view vector, and you could call gluLookAt with any one of those points and still create the same matrix. I've always remembered the three params to gluLookAt as "look" (the eye position), "at" (where your gaze is directed), and "up". Why the second param is called "center" instead of "at", I don't know, probably some kind of historical reason. > I guess the manipulator has some notion of the point about > which it orbits, but I couldn't tell you what that is > off-hand. The header will tell you, no doubt. Yep, read the code. Look for something like "getCenter" in MatrixManipulator, that would be a good start. Paul Martz Skew Matrix Software LLC http://www.skew-matrix.com 303 859 9466 _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
