gibberish-dsp/js/filters/filters.js

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

module.exports = function( Gibberish ) {

  const g = Gibberish.genish

  const filters = {
    Filter24Classic : require( './filter24.js'  )( Gibberish ),
    Filter24Moog    : require( './ladder.dsp.js' )( Gibberish ),
    Filter24TB303   : require( './diodeFilterZDF.js' )( Gibberish ),
    Filter12Biquad  : require( './biquad.dsp.js'    )( Gibberish ),
    Filter12SVF     : require( './svf.js'       )( Gibberish ),
    
    // not for use by end-users
    genish: {
      Comb        : require( './combfilter.js' ),
      AllPass     : require( './allpass.js' )
    },

    factory( input, cutoff, saturation, _props, isStereo = false ) {
      let filteredOsc 

      let props = Object.assign({}, filters.defaults, _props )

      switch( props.filterModel ) {
        case 1:
          filteredOsc = g.zd24( input, g.min( g.in('Q'), .9999 ), cutoff, 0 ) // g.max(.005, g.min( cutoff, 1 ) ) )
          break;
        case 2:
          filteredOsc = g.diodeZDF( input, g.min( g.in('Q'), .9999 ), cutoff, saturation, isStereo ) 
          break;
        case 3:
          filteredOsc = g.svf( input, cutoff, g.sub( 1, g.in('Q')), props.filterMode, isStereo, true ) 
          break; 
        case 4:
          filteredOsc = g.biquad( input, cutoff,  g.in('Q'), props.filterMode, isStereo ) 
          break; 
        case 5:
          //isLowPass = g.param( 'lowPass', 1 ),
          filteredOsc = g.filter24( input, g.in('Q'), cutoff, props.filterMode, isStereo )
          break;
        default:
          // return unfiltered signal
          filteredOsc = input //g.filter24( oscWithGain, g.in('resonance'), cutoff, isLowPass )
          break;
      }

      return filteredOsc
    },

    defaults: { filterMode: 0, filterModel:0 }
  }

  filters.export = target => {
    for( let key in filters ) {
      if( key !== 'export' && key !== 'genish' ) {
        target[ key ] = filters[ key ]
      }
    }
  }

return filters

}