Common Music

;;; Common Music example: random walk melody
;;; Generates a short melody using a random walk algorithm

(in-package :cm)

(defun random-walk (start len step)
  (process repeat len
    with pitch = 60
    output (new midi
                :time (now)
                :keynum pitch
                :duration 0.4
                :amplitude 0.7)
    set pitch = (between (- pitch step) (+ pitch step 1))
    set pitch = (max 48 (min 84 pitch))
    wait 0.5))

(events (random-walk 0 16 3) "walk.mid")