;nyquist plug-in
;version 4
;type process
;preview linear
;name "Filter Sweep (Track Input)..."
;action "Filtering..."
;author "dm"

;control type "Filter Type" choice "Low-Pass,High-Pass,Band-Pass" 0
;control intensity "Intensity" int-text "" 1 1 50
;control max-cu-freq "Maximum Cutoff Frequency" float "" 15000 1 22030

;clip to halfwave, scale to max cutoff freq, downsample to control rate, store,
;compute
(defun store-as-cutoff (signal)
  (setf to-store 
    (sim (s-rest 0)
      (force-srate *control-srate* 
        (scale max-cu-freq
          (s-min (const 1) 
            (s-max (s-rest 1) signal))))))
  (putprop '*SCRATCH* (sim (s-rest 0) to-store) 'DM-FSWEEP-CUTOFF)
  *TRACK*)

(defun clear-storage ()
  (remprop '*SCRATCH* 'DM-SWEEP-CUTOFF))

(defun iter-lp (signal cutoff iter)
  (print (snd-length cutoff ny:all))
  (dotimes (n iter signal)
    (setf signal (lp signal cutoff))))

(defun iter-hp (signal cutoff iter)
  (dotimes (n iter signal)
    (setf signal (hp signal cutoff))))

(defun apply-filter (cutoff)
  (let* ((bandwidth (/ *sound-srate* (float intensity) 5.0)))
    (case type
      (0 (iter-lp *TRACK* cutoff intensity))
      (1 (iter-hp *TRACK* cutoff intensity))
      (2 (reson *TRACK* cutoff bandwidth 1)))))

(setq index (get '*TRACK* 'INDEX))
(setq tracks (length (get '*SELECTION* 'TRACKS)))
(if (< tracks 2) 
  (print "Select 2 tracks")
  (if (< index tracks)
      (store-as-cutoff *TRACK*)
      (let ((cutoff (get '*SCRATCH* 'DM-FSWEEP-CUTOFF)))
        (if (= index tracks) (clear-storage))
        (multichan-expand #'apply-filter cutoff))))