gibberish-dsp/js/instruments/clap.dsp.js

Gibberish is designed to be an optimized API for audio synthesis using per-sample techniques.

const g = require( 'genish.js' ),
      instrument = require( './instrument.js' )

const genish = g
  
module.exports = function( Gibberish ) {

  const Clap = argumentProps => {
    'use jsdsp' 

    const clap = Object.create( instrument ),
          decay = g.in( 'decay' ), // 0-1 input value
          scaledDecay = decay * (g.gen.samplerate * 2 ),
          gain  = g.in( 'gain' ),
          spacing = g.in( 'spacing' ), // spacing between clap, in Hzs
          loudness = g.in( 'loudness' ),
          triggerLoudness = g.in( '__triggerLoudness' ),
          cutoff = g.in('cutoff'),
          Q      = g.in('Q')

    const props = Object.assign( {}, Clap.defaults, argumentProps )

    const eg = g.decay( scaledDecay, { initValue:0 } ), 
          check = g.gt( eg, .0005 ),
          noise = -1 + g.noise() * 2,
          rnd = noise,//g.gtp( noise, 0 ),// * eg,
          b   = g.bang(),
          saw = g.phasor( spacing, b, { min:0 }),
          rsaw = 1 - saw,
          saw_env = g.ad( 0, .035 * g.gen.samplerate, { shape:'linear' }), 
          b2 = g.bang(),
          count = g.accum( 1,b2,{ max:Infinity, min:0, initialValue:0 }),
          delayedNoise = g.switch( g.gte( count, g.gen.samplerate * .035 ), rnd, 0 ),
          bpf1 = g.svf( delayedNoise, 1000, .5, 2, false ),

          scaledOut = ( bpf1 * eg + ( rnd * rsaw * saw_env ) ) * gain * loudness * triggerLoudness,
          out = g.svf( scaledOut, cutoff, Q, 1, false )
    
    // XXX TODO : make this work with ifelse. the problem is that poke ugens put their
    // code at the bottom of the callback function, instead of at the end of the
    // associated if/else block.
    const ife = g.switch( check, out, 0 )
    
    clap.env = {
      trigger( vol ) {
        b.trigger()
        eg.trigger( vol )
        b2.trigger()
        saw_env.trigger()
      }
    } 
    
    return Gibberish.factory( clap, ife, ['instruments','clap'], props  )
  }
  
  Clap.defaults = {
    gain: 1,
    spacing:100,
    decay:.2,
    loudness:1,
    __triggerLoudness:1,
    cutoff:900,
    Q:.85
  }

  return Clap

}