/***************************************************/
/*! \class MoogVCF
  \brief STK MoogVCF filter

  This class implements Tim Stilson's MoogVCF filter
  that was used in SynthBuilder.

  2007 Nick Porcaro
*/
/***************************************************/

#include "MoogVCF.h"
#include <cmath>
#define UNITCLIP(x) ((x) > 1.0 ? (1.0) : ((x) < -1.0 ? -1.0 :(x)))
#define SATURATE(x) (UNITCLIP(x))
#define CLAMP_ZERO(a) ((((a)<(StkFloat)1e-12)&&((a)>(StkFloat)-1e-12))?(StkFloat)0.0:(a))

// This separation table is intended for use with the compromise version 
// of the MoogVCF (i.e. with the open-loop zeros on 0.3).  
// The range of the p coef is [-1.0, 0.1].  
// The start of the list corresponsds to p=-1, and the end with p=0.1

#define DEFAULT_SEPARATION_TABLE_LEN 111
static StkFloat defaultSeparationTable[DEFAULT_SEPARATION_TABLE_LEN] = {
  1.0,
  1.000759196,
  1.001498153,
  1.002216252,
  1.002913029,
  1.003587982,
  1.004240607,
  1.004870396,
  1.005476844,
  1.006059443,
  1.006617686,
  1.007151068,
  1.007659081,
  1.008141221,
  1.008596986,
  1.009025875,
  1.009427389,
  1.009801035,
  1.010146319,
  1.010462756,
  1.010749862,
  1.011007158,
  1.011234173,
  1.011430441,
  1.0115955,
  1.011728898,
  1.01183019,
  1.011898939,
  1.011934715,
  1.011937099,
  1.011905681,
  1.01184006,
  1.011739847,
  1.011604663,
  1.011434142,
  1.011227929,
  1.010985682,
  1.01070707,
  1.010391779,
  1.010039506,
  1.009649964,
  1.00922288,
  1.008757996,
  1.008255069,
  1.007713873,
  1.007134198,
  1.00651585,
  1.005858653,
  1.005162446,
  1.004427088,
  1.003652454,
  1.002838436,
  1.001984947,
  1.001091916,
  1.00015929,
  0.999187036,
  0.9981751393,
  0.9971236034,
  0.9960324505,
  0.9949017219,
  0.9937314773,
  0.9925217953,
  0.9912727731,
  0.9899845263,
  0.988657189,
  0.9872909138,
  0.9858858712,
  0.9844422498,
  0.9829602557,
  0.981440113,
  0.9798820625,
  0.9782863624,
  0.9766532874,
  0.9749831287,
  0.9732761933,
  0.9715328041,
  0.9697532993,
  0.9679380319,
  0.9660873695,
  0.9642016937,
  0.9622813998,
  0.9603268964,
  0.9583386048,
  0.9563169585,
  0.9542624029,
  0.9521753946,
  0.9500564013,
  0.9479059007,
  0.9457243805,
  0.9435123377,
  0.941270278,
  0.9389987157,
  0.9366981724,
  0.9343691773,
  0.9320122663,
  0.9296279815,
  0.9272168706,
  0.9247794867,
  0.9223163876,
  0.9198281353,
  0.9173152954,
  0.914778437,
  0.9122181316,
  0.9096349535,
  0.9070294785,
  0.9044022837,
  0.9017539476,
  0.8990850488,
  0.8963961661,
  0.8936878782,
  0.8909607627
};

MoogVCF :: MoogVCF() : Function()
{
  this->clear();
}

MoogVCF :: ~MoogVCF()
{
}

void MoogVCF :: clear()
{
  int i = 4;
  sfb_ = 0;
  while (i--) {
    s[0] = 0;
  }
}

void MoogVCF :: getDefaultSeparationTable(StkFloat **ptr)
{
  *ptr = defaultSeparationTable;
}

int MoogVCF :: defaultSeparationTableLen()
{
  return DEFAULT_SEPARATION_TABLE_LEN;
}

StkFloat MoogVCF :: computeSample(StkFloat input)
{
  printf ("Invalid call to MoogVCF::computeSample");
  return 0;
}

StkFloat MoogVCF :: tick(StkFloat input, StkFloat gain, StkFloat freq)
{
  int j;
  StkFloat A;
  StkFloat tmp;
  StkFloat pval;

  A = sfb_;
  pval = ((StkFloat)0.55)*(freq)-((StkFloat)0.45);
  A = (StkFloat)0.25*(input - A);

  for (j=0; j<4; j++) {
    tmp = s[j];
    A =  SATURATE(((StkFloat)1.538461538461538*((StkFloat)1.0+pval)*A) - pval*tmp);
    s[j] = (StkFloat)CLAMP_ZERO(A);
    A = SATURATE((StkFloat)0.3*tmp + A);
  }
  lastOutput_ = (StkFloat)A;
  A *= gain;
  sfb_ = (StkFloat)A;
  return lastOutput_;
}