Barcamp Bangalore Spring 2016 session - Orchestrating from the Command line

101.xtm

;; A demo of Extempore (https://github.com/digego/extempore)
;; Based on tutorials from http://benswift.me/extempore-docs/index.html
;; and tutorials from the source (https://github.com/digego/extempore/tree/master/examples)

;; Step 1 - Fetch source and compile
;; Step 2 - Configure the editor and get a hang of the keyboard shortcuts
;; Step 3 - Evaluate the following code samples one block at a time

;; extempore basics
;; What is the time now
(print (now))

;; What is the unix-time now
(clock:clock)

;; load the instruments file 
(sys:load "libs/core/instruments.xtm")

;; define a synth using the provided components
;; synth_note_c and synth_fx
(bind-instrument synth synth_note_c synth_fx)

;; add the instrument to the DSP output callback
(bind-func dsp:DSP
  (lambda (in time chan dat)
    (synth in time chan dat)))
(dsp:set! dsp)

;; play a single note
(play-note (now) synth 71 80 10000)

;; schedule three nodes to play in succession
(define play-seq
  (lambda ()
    (play-note (now) synth 60 80 10000)
    (play-note (+ (now) 22050) synth 64 80 10000)
    (play-note (+ (now) 44100) synth 67 80 10000)))
;; play
(play-seq)

;; to play a chord, remove the addition to (now) and try evaluating again

;; take play-seq a notch higher and set up an octave
(define play-octave
  (lambda ()
    (play-note (now) synth 69 80 10000)
    (play-note (+ (now) 22000) synth 71 80 10000)
    (play-note (+ (now) 44000) synth 73 80 10000)
    (play-note (+ (now) 66000) synth 74 80 10000)
    (play-note (+ (now) 88000) synth 76 80 10000)
    (play-note (+ (now) 110000) synth 78 80 10000)
    (play-note (+ (now) 132000) synth 80 80 10000)
    (play-note (+ (now) 154000) synth 81 80 10000)
    ))
;; play
(play-octave)

;; an example of temporal recursion
(define temporal_101
  (lambda ()
    (play-note (now) synth 60 100 *second*)
    (callback (+ (now) (* 2 *second*)) 'temporal_101)))

(temporal_101)

;; The next set of files are available in the source, experiment
;; with each one by one to better understand Extempore
;;
;; core/polysynth.xtm
;; core/audio_101.xtm
;; external/electrofunk.xtm
;; external/game-of-life.xtm

;; That's all, folks!