piano_coupled_strings.h

#ifndef _PIANO_COUPLED_STRINGS_H_
#define _PIANO_COUPLED_STRINGS_H_

#include "Generator.h" // STK
#include "BiQuad.h"
#include "DelayA.h"
#include "PoleZero.h"
#include "TwoZero.h"
#include "Effect.h"
#include "Asymp.h"

using namespace stk;

class CoupledStrings : public Effect
{
 public:
  CoupledStrings();
  ~CoupledStrings() {}

  virtual void clear() {};

  virtual void noteOn (StkFloat frequency, StkFloat amplitude); // needed?
  virtual void noteOff (StkFloat amplitude); // needed?
  virtual void controlChange (int number, StkFloat value); // needed?
  virtual void setFrequency (StkFloat frequency);

  // Parameters
  void setDetuningFactor(StkFloat factor);
  void setStiffnessFactor(StkFloat factor);

  // Helpers
  static StkFloat AllPassPhase(StkFloat a1, StkFloat wT);
  static StkFloat PoleZeroPhase(StkFloat b0, StkFloat b1, StkFloat a1, StkFloat wT);
  static int FrequencyToNoteNumber(StkFloat frequency);
  static StkFloat NoteNumberToFrequency(int note);

  virtual StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
  virtual StkFloat tick( StkFloat, unsigned int channel = 0 );

 protected:
  StkFloat delayLength(StkFloat freq, StkFloat stiffnessCoefficient);
  void calcCouplingFilter();

  StkFloat computeSample(StkFloat input);

  PoleZero stiffnessAP[6];
  DelayA delay1, delay2;

  PoleZero couplingPoleZero;

  Asymp loopGain;

  StkFloat prev_y1, prev_y2;

  StkFloat detuningFactor;
  StkFloat frequency, freq1, freq2;
  StkFloat stiffnessFactor;
  int noteNumber;

  StkFloat couplingB0;
  StkFloat couplingB1;
  StkFloat couplingA1;
};

#endif // _PIANO_COUPLED_STRINGS_H_