basic.clj

;; This is a WIP attempt to convert SuperCollider's PingPong class
;; https://github.com/supercollider/supercollider/blob/cca12ff02a774a9ea212e8883551d3565bb24a6f/SCClassLibrary/Common/Audio/DelayWr.sc#L1
;; into Overtone/clojure code so that it can be used as part of
;; a larger Overtone synthdef.
;; Underneath the ping-pong cgen below is a variation of the beep
;; synthdef used in Sonic Pi, which I am attempting to add ping pong
;; delay to.
;; I've been attempting to compile and test this according to
;; https://github.com/samaaron/sonic-pi/blob/master/SYNTH_DESIGN.md
;; So far, several errors have been temporarily worked around
;; by hardcoding various numbers in to replace several functions,
;; but there are still errors being generated with this design.
;; (Eventually, a way to bring any necessary functions back in
;; Will need to be found).

(ns sonic-pi.synths.basic
  (:use [overtone.live])
  (:require [sonic-pi.synths.core :as core]))

(defn rotation [xs n]
  "Rotate a list N places to the left."
  (let [c (count xs)]
  (take c (drop (mod n c) (cycle xs)))))

(defn wrap-val [x min-x max-x]
  (let [x-range (- (inc max-x) min-x)]
    (-> x (- min-x) (mod x-range) (+ min-x))))

(defcgen ping-pong
    "Create a synth-local buffer."
      [bufnum {:default 0 :doc "The id of the buffer to use."}
       inputs {:doc "The input signals to the effect."}
       delay-time {:default 0.2 :doc "The amount of time to delay between outputs"}
       feedback {:default 0.5 :doc "The amount of feedback for the effect"}
       r {:default 1 :doc "Which output to start the effect on"}
       ]
       (:ar (let [delay-samps (Math/round (max 0 (- (* delay-time 44100) 1024)))
                                 frames (buf-frames:kr bufnum)
                                 phase (phasor:ar 0 1 0 frames)
                                 feedback-channels (* (local-in:ar (count inputs)) feedback)
                                 delayed-signals (buf-rd:ar (count inputs) bufnum (wrap-val ((- phase delay-samps) 0 frames)) 0)]
                                 (local-out:ar delayed-signals)
                                 (buf-wr:ar (rotation (+ inputs feedback-channels) r)))))

(without-namespace-in-synthdef 
  (defsynth sonic-pi-beep [note 52
                          note_slide 0
                          note_slide_shape 1
                          note_slide_curve 0
                          amp 1
                          amp_slide 0
                          amp_slide_shape 1
                          amp_slide_curve 0
                          pan 0
                          pan_slide 0
                          pan_slide_shape 1
                          pan_slide_curve 0
                          attack 0
                          decay 0
                          sustain 0
                          release 1
                          attack_level 1
                          decay_level -1
                          sustain_level 1
                          env_curve 1
                          out_bus 0]
   (let [decay_level (select:kr (= -1 decay_level) [decay_level sustain_level])
         note        (varlag note note_slide note_slide_curve note_slide_shape)
         amp         (varlag amp amp_slide amp_slide_curve amp_slide_shape)
         amp-fudge   1
         pan         (varlag pan pan_slide pan_slide_curve pan_slide_shape)
         freq        (midicps note)
         snd         (sin-osc freq)
         env         (env-gen:kr (core/shaped-adsr attack decay sustain release attack_level decay_level sustain_level env_curve) :action FREE)
         buf         (local-buf (* 44100 2) 2)
         echo_snd    (ping-pong buf [snd snd])
         ]
     (out out_bus (pan2 (* amp-fudge env echo_snd) pan amp)))))

 (core/save-synthdef sonic-pi-beep)