FreeVerb.h

#ifndef STK_FREEVERB_H
#define STK_FREEVERB_H
 
#include "Effect.h"
#include "Delay.h"
#include "OnePole.h"
 
namespace stk {
 
/***********************************************************************/
/***********************************************************************/
 
class FreeVerb : public Effect
{   
 public:
 
  FreeVerb();
 
  ~FreeVerb();
 
  void setEffectMix( StkFloat mix );
 
  void setRoomSize( StkFloat value );
 
  StkFloat getRoomSize( void );
 
  void setDamping( StkFloat value );
 
  StkFloat getDamping( void );
 
  void setWidth( StkFloat value );
 
  StkFloat getWidth( void );
 
  void setMode( bool isFrozen );
 
  StkFloat getMode( void );
 
  void clear( void );
 
 
  StkFloat lastOut( unsigned int channel = 0 );
 
 
  StkFloat tick( StkFloat inputL, StkFloat inputR = 0.0, unsigned int channel = 0 );
 
 
  StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
 
 
  StkFrames& tick( StkFrames& iFrames, StkFrames &oFrames, unsigned int iChannel = 0, unsigned int oChannel = 0 );
 
 protected:
  void update( void );
 
  // Clamp very small floats to zero, version from
  // http://music.columbia.edu/pipermail/linux-audio-user/2004-July/013489.html .
  // However, this is for 32-bit floats only.
  //static inline StkFloat undenormalize( volatile StkFloat s ) { 
  //  s += 9.8607615E-32f; 
  //  return s - 9.8607615E-32f; 
  //}
    
  static const int nCombs = 8;
  static const int nAllpasses = 4;
  static const int stereoSpread = 23;
  static const StkFloat fixedGain;
  static const StkFloat scaleWet;
  static const StkFloat scaleDry;
  static const StkFloat scaleDamp;
  static const StkFloat scaleRoom;
  static const StkFloat offsetRoom;
 
  // Delay line lengths for 44100Hz sampling rate.
  static int cDelayLengths[nCombs];
  static int aDelayLengths[nAllpasses];
 
  StkFloat g_;        // allpass coefficient
  StkFloat gain_;
  StkFloat roomSizeMem_, roomSize_;
  StkFloat dampMem_, damp_;
  StkFloat wet1_, wet2_;
  StkFloat dry_;
  StkFloat width_;
  bool frozenMode_;
 
  // LBFC: Lowpass Feedback Comb Filters
  Delay combDelayL_[nCombs];
  Delay combDelayR_[nCombs];
  OnePole combLPL_[nCombs];
  OnePole combLPR_[nCombs];
        
  // AP: Allpass Filters
  Delay allPassDelayL_[nAllpasses];
  Delay allPassDelayR_[nAllpasses];
};
 
inline StkFloat FreeVerb :: lastOut( unsigned int channel )
{
#if defined(_STK_DEBUG_)
  if ( channel > 1 ) {
    oStream_ << "FreeVerb::lastOut(): channel argument must be less than 2!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  return lastFrame_[channel];
}
 
inline StkFloat FreeVerb::tick( StkFloat inputL, StkFloat inputR, unsigned int channel )
{
#if defined(_STK_DEBUG_)
  if ( channel > 1 ) {
    oStream_ << "FreeVerb::tick(): channel argument must be less than 2!";
    handleError(StkError::FUNCTION_ARGUMENT);
  }
#endif
 
  StkFloat fInput = (inputL + inputR) * gain_;
  StkFloat outL = 0.0;
  StkFloat outR = 0.0;
 
  // Parallel LBCF filters
  for ( int i = 0; i < nCombs; i++ ) {
    // Left channel
    //StkFloat yn = fInput + (roomSize_ * FreeVerb::undenormalize(combLPL_[i].tick(FreeVerb::undenormalize(combDelayL_[i].nextOut()))));
    StkFloat yn = fInput + (roomSize_ * combLPL_[i].tick( combDelayL_[i].nextOut() ) );
    combDelayL_[i].tick(yn);
    outL += yn;
 
    // Right channel
    //yn = fInput + (roomSize_ * FreeVerb::undenormalize(combLPR_[i].tick(FreeVerb::undenormalize(combDelayR_[i].nextOut()))));
    yn = fInput + (roomSize_ * combLPR_[i].tick( combDelayR_[i].nextOut() ) );
    combDelayR_[i].tick(yn);
    outR += yn;
  }
 
  // Series allpass filters
  for ( int i = 0; i < nAllpasses; i++ ) {
    // Left channel
    //StkFloat vn_m = FreeVerb::undenormalize(allPassDelayL_[i].nextOut());
    StkFloat vn_m = allPassDelayL_[i].nextOut();
    StkFloat vn = outL + (g_ * vn_m);
    allPassDelayL_[i].tick(vn);
        
    // calculate output
    outL = -vn + (1.0 + g_)*vn_m;
 
    // Right channel
    //vn_m = FreeVerb::undenormalize(allPassDelayR_[i].nextOut());
    vn_m = allPassDelayR_[i].nextOut();
    vn = outR + (g_ * vn_m);
    allPassDelayR_[i].tick(vn);
 
    // calculate output
    outR = -vn + (1.0 + g_)*vn_m;
  }
 
  // Mix output
  lastFrame_[0] = outL*wet1_ + outR*wet2_ + inputL*dry_;
  lastFrame_[1] = outR*wet1_ + outL*wet2_ + inputR*dry_;
 
  /*
  // Hard limiter ... there's not much else we can do at this point
  if ( lastFrame_[0] >= 1.0 ) {
    lastFrame_[0] = 0.9999;
  }
  if ( lastFrame_[0] <= -1.0 ) {
    lastFrame_[0] = -0.9999;
  }
  if ( lastFrame_[1] >= 1.0 ) {
    lastFrame_[1] = 0.9999;
  }
  if ( lastFrame_[1] <= -1.0 ) {
    lastFrame_[1] = -0.9999;
  }
  */
 
  return lastFrame_[channel];
}
 
}
 
#endif