;;;
;;; Chapter 12
;;; Etudes, Op. 4: Score Generation
;;;
;;; Examples and Interactions from scores.html
;;; generated from Common Music 2.4.1 on 19 Jan 2004, 08:23:15.
;;;


;;;
;;; Interaction 1: Using the pwd and cd functions.
;;;

(pwd)
(cd "/tmp/")
(pwd)

;;;
;;; Interaction 2: Generating a MIDI event to a MIDI file.
;;;

(define one (new midi :time 0
                :keynum 60 :duration 2))
(events one "myscore.mid")
(midi-file-print "myscore.mid")

;;;
;;; Interaction 3: Listening to a MIDI file on OSX.
;;;

;;; (osx-play-midi-file "myscore.mid")

;;;
;;; Interaction 4: Activating file versioning and setting an output hook for automatic playback.
;;;

;;; (set-midi-file-versions! true)
;;; (set-midi-output-hook! #'osx-play-midi-file)

;;;
;;; Example 1: Definition of a list of events.
;;;

(define up
  (loop for key from 60 to 72 
        for beg from 0 by .1
        collect (new midi :time beg
                     :keynum key
                     :duration 1)))

;;;
;;; Interaction 5: Generating a score from a list of events.
;;;

(events up "myscore.mid")

;;;
;;; Example 2: Create a list of midi events between two key numbers.
;;;

;; see this thread for why the simple "for key from key1 by step" does not work in sbcl
;; http://ccrma-mail.stanford.edu/pipermail/cmdist/2005-October/002697.html

(define (strums key1 key2 rate dur amp)
    (let ((step (if (< key2 key1) -1 1))
          (diff (abs (- key1 key2))))
      (loop repeat (+ diff 1)
            for key = key1 then (+ key step)
            for beg from 0 by rate
	    collect (new midi
                      :time beg
                      :duration dur
                      :amplitude amp
                      :keynum key))))

;;;
;;; Interaction 6: Generating strum data.
;;;

(pprint (strums 60 61 .1 1 .2))

;;;
;;; Interaction 7: Creating two strum sequences.
;;;

(new seq :name 'ups
     :subobjects (strums 48 60 .1 1 .4))
(new seq :name 'downs
     :subobjects (strums 84 72 .1 1 .4))
(events (list #&ups #&downs) "myscore.mid")

;;;
;;; Interaction 8: The effect of start time offsets.
;;;

(events (list #&ups #&downs) "myscore.mid" 5)
(events (list #&ups #&downs) "myscore.mid" '(0 .5))
(events (list #&ups #&downs #&ups #&downs )
        "myscore.mid"
        '(0 .5 1 1.5))