gibberish-dsp/js/envelopes/envelopes.js

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

const g = require( 'genish.js' )

module.exports = function( Gibberish ) {

  const Envelopes = {
    AD     : require( './ad.js' )( Gibberish ),
    ADSR   : require( './adsr.js' )( Gibberish ),
    Ramp   : require( './ramp.js' )( Gibberish ),

    export : target => {
      for( let key in Envelopes ) {
        if( key !== 'export' && key !== 'factory' ) {
          target[ key ] = Envelopes[ key ]
        }
      }
    },

    factory( useADSR, shape, attack, decay, sustain, sustainLevel, release, triggerRelease=false ) {
      let env

      // deliberate use of single = to accomodate both 1 and true
      if( useADSR != true ) {
        env = g.ad( attack, decay, { shape }) 
      }else {
        env = g.adsr( attack, decay, sustain, sustainLevel, release, { shape, triggerRelease })
        env.advance = env.release
      }

      return env
    }
  } 

  return Envelopes
}