;;; Defining a recursive process with four input args. 
;;; sprout's second arg is the time to start the sprouted object.
;;;
;;; http://serendip.brynmawr.edu/playground/sierpinski.html
;;; http://astronomy.swin.edu.au/~pbourke/fractals/gasket/

;;; using the fm-violin

(define (sierpinski knum ints dur amp depth)
  (let ((len (length ints)))
    (process for i in ints
             for k = (transpose knum i)
             output (new fm-violin :startime (now) :dur dur 
                         :amplitude amp :frequency (hertz k))
             when (> depth 1)
	     ;; sprout a process on output note
	     sprout
             (sierpinski (transpose k 12) ints
                         (/ dur len) amp (- depth 1))
             
             
             wait dur)))

;;; using midi output

(define (sierpinski knum ints dur amp depth)
  (let ((len (length ints)))
    (process for i in ints
             for k = (transpose knum i)
             output (new midi :time (now) :duration dur 
                         :amplitude amp :keynum k)
             when (> depth 1)
	     ;; sprout a process on output note
	     sprout
             (sierpinski (transpose k 12) ints
                         (/ dur len) amp (- depth 1))
             
             
             wait dur)))

(define (sierpinski knum ints dur amp chan depth)
  (let ((len (length ints)))
    (process for i in ints
             for k = (transpose knum i)
             output (new midi :time (now) :duration dur :channel chan
                         :amplitude amp :keynum k)
             when (> depth 1)
	     ;; sprout a process on output note
	     sprout
             (sierpinski (transpose k 12) ints
                         (/ dur len) amp (+ chan 1) (- depth 1))
             
             
             wait dur)))

#|

(defparameter *pm* (portmidi-open :output 0 :input 1))

(rts (sierpinski 'a0 '(0 7 5 ) 3 .1 4) *pm*)
(rts (sierpinski 'a0 '(0 -1 2 13) 6 .1 0 4) *pm*)

(events (sierpinski 'a0 '(0 7 5 ) 3 .1 4) "test.snd")
(events (sierpinski 'a0 '(0 -1 2 13) 6 .1 4) "test.snd")

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