anchor.diff:               intersect-param)))
   
   ;; newtonworldrayprefiltercallback
  -(defcallback %world-ray-prefilter-cb :float ((body-ptr :pointer)
  -                                             (geom-ptr :pointer)
  -                                             (user-data :pointer))
  +(defcallback %world-ray-prefilter-cb :uint ((body-ptr :pointer)
  +                                            (geom-ptr :pointer)
  +                                            (user-data :pointer))
     (let ((world (%world-by-id (pointer-address user-data)))
           (body (%body-ptr->body body-ptr))
           (shape-hit (%geom-ptr->geom geom-ptr)))
  -    (funcall (%world-ray-filter-callback world) body shape-hit)))
  +    (funcall (%world-ray-prefilter-callback world) body shape-hit)))
   
   ;; newtonworldupdatelistenercallback
   (defcallback %world-update-listener-cb :void ((world-ptr :pointer)
  
positive.code: ;;------------------------------------------------------------
  ;; newtonslidercallback
  
  (defcallback %slider-cb :void
      ((joint-ptr :pointer)
       (data (:pointer NewtonHingeSliderUpdateDesc)))
    (with-foreign-slots ((m-accel m-minFriction m-maxFriction m-timestep)
  
negative.code: ;;------------------------------------------------------------
  ;; newtonuniversalcallback
  
  (defcallback %universal-cb :uint
      ((joint-ptr :pointer)
       (data (:pointer NewtonHingeSliderUpdateDesc)))
    (with-foreign-slots ((m-accel m-minFriction m-maxFriction m-timestep)
  