gibberish-dsp/js/misc/bus.js

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

let g = require( 'genish.js' ),
    ugen = require( '../ugen.js' )(),
    __proxy= require( '../workletProxy.js' )

module.exports = function( Gibberish ) {
  const proxy = __proxy( Gibberish )
  const Bus = Object.create( ugen )

  Object.assign( Bus, {
    gain: {
      set( v ) {
        this.mul.inputs[ 1 ] = v
        Gibberish.dirty( this )
      },
      get() {
        return this.mul[ 1 ]
      }
    },

    __addInput( input ) {
      this.sum.inputs.push( input )
      Gibberish.dirty( this )
    },

    create( _props ) {
      const props = Object.assign({}, Bus.defaults, { inputs:[0] }, _props )

      // MUST PREVENT PROXY
      // Othherwise these binops are created in the worklet and sent
      // across the thread to be instantiated, and then instantiated again
      // when the bus is created in the processor thread, messing up the various
      // uids involved. By preventing proxying the binops are only created
      // a single time when the bus is sent across the thread.
      Gibberish.preventProxy = true
      const sum = Gibberish.binops.Add( ...props.inputs )
      const mul = Gibberish.binops.Mul( sum, props.gain )
      Gibberish.preventProxy = false

      const graph = Gibberish.Panner({ input:mul, pan: props.pan })

      graph.sum = sum
      graph.mul = mul
      graph.disconnectUgen = Bus.disconnectUgen

      graph.__properties__ = props

      const out = props.__useProxy__ === true ? proxy( ['Bus'], props, graph ) : graph

      Object.defineProperty( out, 'gain', Bus.gain )

      if( false && Gibberish.preventProxy === false && Gibberish.mode === 'worklet' ) {
        const meta = {
          address:'add',
          name:['Bus'],
          props, 
          id:graph.id
        }
        Gibberish.worklet.port.postMessage( meta )
        Gibberish.worklet.port.postMessage({ 
          address:'method', 
          object:graph.id,
          name:'connect',
          args:[]
        })
      }

      return out 
    },

    disconnectUgen( ugen ) {
      let removeIdx = this.sum.inputs.indexOf( ugen )

      if( removeIdx !== -1 ) {
        this.sum.inputs.splice( removeIdx, 1 )
        Gibberish.dirty( this )
      }
    },

    // can't include inputs here as it will be sucked up by Gibber,
    // instead pass during Object.assign() after defaults.
    defaults: { gain:1, pan:.5, __useProxy__:true }
  })

  const constructor = Bus.create.bind( Bus )
  constructor.defaults = Bus.defaults

  return constructor
}