AM Posted May 21, 2018 Share Posted May 21, 2018 (edited) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;; rnd-walk in a pitchfield - with interval-control ;;; ;;; this is a little function which does an rnd-walk in a special way ;;; the function is checking all possible interval-pairs first inside the pitchfield ;;; so that is on one hand all the time "inside" the pitchfield/sieve, but also only ;;; uses the :POSSIBLE-INTERVALS, so you could control the "interval-color" of the walk ;;; in an non-chromatic-pitchfield/sieve ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; (defun enlarge-intervals (possible-intervals &key (octaves 2)) (let ((possible-intervals (append possible-intervals (loop repeat octaves for i = 12 then (incf i 12) append (x+b possible-intervals i))))) (append possible-intervals (neg! possible-intervals)))) ;(enlarge-intervals '(2 3 4)) ;;;;;;;;;;; (defun special-rnd-walk (n &key pitchfield startpitch possible-intervals (interval-octaves 2)) (let ((int-list (loop for i in pitchfield collect (list (pitch-to-midi i) (loop for x in pitchfield with int do (setf int (car (pitch-to-interval (list i x)))) when (/= int 0) collect int)))) (possible-intervals (enlarge-intervals possible-intervals :octaves interval-octaves))) (append (list startpitch) (midi-to-pitch (loop repeat n with int with pitch = (pitch-to-midi startpitch) do (setf int (rnd-pick (filter-preserve possible-intervals (cadr (assoc pitch int-list))))) when (null int) do (setf int (rnd-pick (cadr (assoc pitch int-list)))) collect (setf pitch (pitch-to-midi (cadr (interval-to-pitch (list int) :start (midi-to-pitch pitch)))))))))) ;;;;;;;;;;; EXAMPLES ;;; rnd-walk in a "chromatic-field" - as the most easiest example/way ;;; => so all possible-intervals could be used -> THE ORDINARY WAY... (special-rnd-walk 20 :startpitch 'cs4 :pitchfield '(gs3 a3 bb3 b3 c4 cs4 d4 ds4 e4 f4 fs4 g4 gs4 a4) :possible-intervals '(1 2 3)) ;;; BUT have a look to the next examples!!! ;;; rnd-walk in a PITCHFIELD -> the function is checking all possible interval-pairs inside the pitchfield ;;; so that the rnd-walk INSIDE the PITCHFIELD could be done with specific intervals (if they are inside the field) ;;; COMPARE THE RESULT with the PITCHFIELD!!! ;;; (setf pitchfield '(gs3 cs4 ds4 g4 a4 b4 d5 e5 fs5 bb5 c6 f6)) ;;; "interval-color" of the walk is made with :possible-intervals (special-rnd-walk 5 :startpitch 'ds4 :pitchfield '(gs3 cs4 ds4 g4 a4 b4 d5 e5 fs5 bb5 c6 f6) :possible-intervals '(1 2 3)) ; + octaves of this intervals (special-rnd-walk 10 :startpitch 'ds4 :pitchfield '(gs3 cs4 ds4 g4 a4 b4 d5 e5 fs5 bb5 c6 f6) :possible-intervals '(1 3 4 5) :interval-octaves 0) ;;; reduced interval-span (special-rnd-walk 10 :startpitch 'ds4 :pitchfield '(gs3 cs4 ds4 g4 a4 b4 d5 e5 fs5 bb5 c6 f6) :possible-intervals '(5 6 7)) ; + octaves of this intervals more examples -> SOUND ;;; rnd-versions so you will here the different interval-colors inside the pitchfield (setf seq (gen-sieve '(f3 fs6) '(4 2 1 1 1 2 4 7) :type :pitch)) ;(setf seq (gen-sieve '(f3 fs6) '(7 4 2 1 1 1 2 4) :type :pitch)) ;(setf seq '(gs3 cs4 ds4 g4 a4 b4 d5 e5 fs5 bb5 c6 f6)) (setf pitchlist (special-rnd-walk (rnd-pick '(3 5 7 11)) :startpitch (rnd-pick seq) :pitchfield seq :possible-intervals (rnd-pick '((1 2) (3 4) (5 6 7))) :interval-octaves 3)) (def-score intervals (:title "walk" :key-signature 'atonal :time-signature '(4 4) :tempo 90) (instrument :omn (make-omn :pitch pitchlist :length '(t) :span :pitch) :channel 1 :sound 'gm :program 'acoustic-grand-piano)) ;;; rnd-walk in SIEVE only with intervals '(5 6 8) (setf seq (gen-sieve '((c4 g7) (c2 g7)) '((2 1 10) (3 5)) :type :pitch)) (setf pitchlist (special-rnd-walk 30 :startpitch (rnd-pick seq) :pitchfield seq :possible-intervals '(5 6 8))) (def-score intervals (:title "intervals" :key-signature 'atonal :time-signature '(4 4) :tempo 90) (instrument :omn (make-omn :pitch pitchlist :length '(t) :span :pitch) :channel 1 :sound 'gm :program 'acoustic-grand-piano)) (setf seq (gen-sieve '((c2 g7) (c2 g7)) '((2 1 10) (3 5)) :type :pitch)) ;;; EXAMPLE with changes -> all inside the same SIEVE (setf pitchlist (append (special-rnd-walk 50 :startpitch (rnd-pick seq) :pitchfield seq :possible-intervals '(1)) ; minor second (special-rnd-walk 50 :startpitch (rnd-pick seq) :pitchfield seq :possible-intervals '(2)) ; major second (special-rnd-walk 50 :startpitch (rnd-pick seq) :pitchfield seq :possible-intervals '(3 4)) ;thirds (special-rnd-walk 50 :startpitch (rnd-pick seq) :pitchfield seq :possible-intervals '(5 7)))) ; fourth-fifth (def-score intervals (:title "intervals" :key-signature 'atonal :time-signature '(4 4) :tempo 90) (instrument :omn (make-omn :pitch pitchlist :length '(t) :span :pitch) :channel 1 :sound 'gm :program 'acoustic-grand-piano)) Edited May 21, 2018 by AM examples + new version Stephane Boussuge and RST 2 Quote Link to comment Share on other sites More sharing options...
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