# $p0 ; amplitude
# $p1 ; wavelength (in pixels)
# $p2 ; velocity 
# $p3 ; outward (TRUE)

&rfx_sendmsg (
  qq{
    (begin
      (if (= $frame $start)
        (define next-phase (make-progressor 0
                                            (if (zero? $p3) 
                                              (* $p2 (/ 360 (- $end $start)))
                                              (* $p2 (/ 360 (- $start $end))) ))))
      (let* ((input-file (string-append "$curtmpdir" DIR-SEPARATOR "$in"))
             (image (car (gimp-file-load RUN-NONINTERACTIVE input-file input-file)))
             (layer (car (gimp-image-get-active-layer image))) )
        (plug-in-waves RUN-NONINTERACTIVE
                       image
                       layer
                       $p0
                       (next-phase)
                       $p1
                       0
                       FALSE)
        (rfx-save-frame image "$out") 
        )
      )
    }
  );

