First London Clojurians Clojure Dojo and dabble with Overtone - in honor of St Patrick's Day

diddly.clj

; Authors - Greg Hawkins, Patrick Gallagher, Dan Osborne
(ns diddly.core
  (:use [overtone.core]
        [overtone.inst.piano]
        [overtone.inst.synth]))

(boot-external-server)

(definst saw-wave [freq 440 attack 0.01 sustain 0.2 release 0.05 vol 0.4]
  (* (env-gen (env-lin attack sustain release) 1 1 0 1 FREE)
     (saw freq)
     vol))

(defn saw-note [n]
  (saw-wave (midi->hz (note n))))

(defn play-chord [c]
  (doseq [note c] (saw-note note)))

(def kick (sample (freesound-path 2086)))
(def bodhrun (sample (freesound-path 65833)))

(def progression [[:D3 :major]
                  [:G3 :major]
                  [:D3 :major]
                  [:A3 :major]
                  [:B3 :minor]
                  [:A3 :major]
                  [:G3 :major]
                  [:D3 :major]])

(defn looper [nome tick bass bod play-note]
  (let [beat (nome)]
    
    (case (mod tick 3)
      0 (do (at (nome beat) (bass)) (at (nome beat) (play-note))) 
      1 (when (> 0.5 (rand)) (at (nome beat) (play-note)))
      2 (do (at (nome beat) (bod)) (at (nome beat) (play-note))))
    
    (when (zero? (mod tick 12))
      (at (nome beat) (play-chord (apply chord (nth progression (mod (/ tick 12) 4))))))
    
    (apply-at (nome (inc beat)) looper nome (inc tick) bass bod play-note [])))

(def D-ISH [:D4 :D4 :D4 :E4 :F#4 :F#4 :G4 :A4 :A4 :A4 :B4 :C#4 :D5])

(defn play-note []
  (saw-note (rand-nth D-ISH)))

(def irish-tempo (metronome (* 250 3)))

(defn play-tune []
  (looper irish-tempo 0 
          (fn [] (kick 1 :amp 5.0)) 
          (fn [] (bodhrun 1 :amp 7.0))
          play-note))

(defn -main[& args]
  (play-tune))

project.clj

(defproject diddly "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :dependencies [[org.clojure/clojure "1.5.1"]
                 [overtone "0.9.1"]]
  :main diddly.core)