question: public void dolly ( double zDelta ) { double distance = camera . getDistanceToCoR ( ) ; zDelta = zDelta * distance * 0.01 ; if ( ( ( distance + zDelta ) < closestDistance ) && ( zDelta < 0 ) ) { return ; } direction . set ( camera . getDirection ( ) ) ; location . set ( camera . getLocation ( ) ) ; location . subtractLocal ( direction . multiplyLocal ( zDelta ) ) ; distance = location . distance ( sceneBounds . getCenter ( ) ) ; if ( ( distance > sceneBounds . getRadius ( ) * 4 ) && ( zDelta > 0 ) ) { return ; } camera . setLocation ( location ) ; updateFromCamera ( ) ; updateCrosshair ( ) ; updateGeometricState ( 0 ) ; changed . set ( true ) ; updateStatus ( ) ; }
target:  Perform a dolly operation