Live demo

fugue is...

• a tool for making music with a web browser
• a library and bootstrapped ClojureScript IDE for audio/midi applications
• Overtone on the web

...and lets you...

• quickly prototype musical programming experiments without installation or setup
• rapidly develop user interfaces with Reagent, live in the browser
• control a modular synthesizer from the web (if you have a DC-coupled audio interface)
• get the most out of the Web Audio and Web MIDI APIs

...with some nifty features

• operators are just functions that return synthdefs, and can be composed (e.g. with ->)
• parameters for operators can be other synthdefs, Watchables (like Reagent atoms), or just values
• synthdefs are just values, implemented with directed loom graphs
• synthdefs are constructed using a context (audio in/out or midi, which requires browser permission)
• discrete signals (like midi) are implemented with core.async channels
• midi effects, gates, envelopes, ramps, and other transformations are modeled with transducers

(def tempo (reagent.core/atom 120))
(def decay (midi-ctrl "FaderFox" 33 0.3 0.8))
(def cutoff (lfo 400 200 0.2))

(def m (metro tempo))

(def freq-env
  (->> m
       (sequencer [64 62 60 62 64 64 64 64])
       hz
       (env-gen (slide 0.01)))
       
 (def gain-env
   (env-gen (perc 0.1 decay) (sequencer [1 1 1 1 1 1 1 0] m) 0.5))

(def mary-had-a-little-synth
  (-> (saw freq-env)
      (gain gain-env)
      (lpf cutoff 2)
      (panner 0)
      (out))))

(make-synth (make-ctx) mary-had-a-little-synth)

• These operators match the Web Audio API AudioNodes.
• All arguments to these functions (except the ones called "in", which must be a synthdef) can be numbers, Watchables (like Reagent atoms), or other synthdefs

(out node channel)
(in channel)
(gain in & gains)
(mix & ins)
(const & offsets)
(sin-osc freq detune)
(saw freq detune)
(sqare freq detune)
(tri-osc freq detune)
(lpf in frequency q)
(bpf in frequency q)
(hpf in frequency q)
(delay-node in time)
(panner in amt)
(compressor threshold knee ratio reduction attack release)

• MIDI in/out requires a browser permission, and the context is loaded separately via midi/make-context
• These operators return synthdefs, which are built into core.async channels and transducers upon construction
• Transducers are a natural way to model MIDI effects, as they are potentially stateful transformers agnostic of their carriers

(midi-in name)           ; Acquires a midi channel
(ctrl midi note min max) ; Maps the control value at note to range [min, max)
(note midi)              ; Gets the "current" note as defined by a priority function (by default, `last`)
(hz midi)                ; Produces a frequency channel from a note channel
(gate midi)              ; Produces a gate channel from a midi channel
(kb)                     ; A midi channel controlled by the computer keyboard (a is C, w is C#, s is D, etc; z is octave down, x is octave up) 

• Envelopes control audio parameters over time.
• Envelopes are just synthdefs, and are defined by an envdef and triggered by a gate channel, sort of like how Overtone does it.
• envdefs like adsr are transducers that map their parameters (attack, decay, etc) to a function on a gate value that returns a sequence of stages
• env-gen is a transducer that takes these envdefs and, when it receives a new gate, uses the stages defined by the envdef to produce ramps that control the parameters

(adsr a d s r)
(perc a d)
(env-gen env gate scale bias)

• AudioBuffers must be loaded ahead of time, and included in the context when building a synthdef
• Fugue provides tools for uploading and decoding files to AudioBuffers and caching them for playback.
• Samplers can be 1-shot (trigger) or gate
• Samples can be tuned using the detune parameter, which is in cents so it can be played like an instrument with a midi signal (offset from middle C, midi note 60)

(sampler buffer-name trigger detune)

The convolver node (used primarily for reverbs) also uses audio buffers, and can be passed an audio buffer name in the same way:

(convolver in buffer-name)

• Metronomes are channels that fire repeatedly with a given interval
• Metronomes can be used as gate values, to fire an envelope or trigger a sequencer
• To get over the "Tale of Two Clocks" problem, metronomes deliberately fire early, but use the AudioContext's clock to determine how early they are and provide a delay in their payload. This delay is accounted for by envelopes, which will push back their ramps accordingly.

(bpm tempo) ; converts beats-per-minute to period
(metro period-ms)

• Uses cljs.js/eval-str to evaluate on changes
• If the last expression is a Hiccup vector, it is rendered
• The fugue.api is imported into the environment, and contains aliases for the various operators
• fugue.ctx-ctrls contains tooling for managing the AudioContext, which must be done manually.

Uses Leiningen

lein figwheel

starts a development server at localhost:3449.

lein do clean, cljsbuild once
cd resources/public
python3 -m http.server 8000

to preview a build production at localhost:8000.

GitHub Actions are set up to build to GitHub pages.

• Klangmeister - same concept, different execution
• Overtone - uses the powerful SuperCollider engine

Copyright © 2020 pdv

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.