;;; -*- Syntax: Common-Lisp; Package: COMMON-MUSIC; Base: 10; Mode: Lisp -*-

;;;  Streaming showing the tendency of the ear to group lines of music by register.
;;;  This example plays a monophonic line with notes in alternating register, 
;;;  first slow then fast. The streaming effect occurs at higher tempos only. 

;;; we define a violin player that's going to play our melody. 
;;; to communicate with the player we use the following parameters:
;;; start-time -> when in time to start the melody
;;; events     -> number of notes we want the player to play
;;; tempo      -> the tempo in bps
;;; octaves    -> a pattern with the octave offsets

(defun one-violin (start-time events tempo octaves)
  (let* (;; "shadow" the global tempo variable
	 (*tempo* tempo)
	 ;; our pitch stream
	 (pitch (new cycle c3 d e parsing #'hertz))
	 ;; our rhythm stream (which will double as duration control)
	 (rhythm (new cycle q parsing #'rhythm))
	 ;; the time counter, starts at "start-time"
	 (time start-time))
    (loop
      ;; we go through the loop "events" times
      repeat events
      ;; this is going to be the duration for the current note
      for dur = (next rhythm)
      ;; this is going to be the frequency of the note
      for freq = (* (next pitch)(next octaves))
      do
      (fm-violin time dur freq 0.1)
      ;; increment out time counter _after_ the note is played
      ;; as we use the rhytm as duration, notes will be "legato"
      (incf time dur))))

#|
 A simple example of streaming...

 (with-sound()
    (one-violin 0 15 (* 60 2) (new cycle 2 4))
    (one-violin (/ 15 2.0) 60 (* 60 7)(new cycle 2 4)))      
|#