/***************************************************/
/*! \class StifKarp
    \brief STK plucked stiff string instrument.

    This class implements a simple plucked string
    algorithm (Karplus Strong) with enhancements
    (Jaffe-Smith, Smith, and others), including
    string stiffness and pluck position controls.
    The stiffness is modeled with allpass filters.

    This is a digital waveguide model, making its
    use possibly subject to patents held by
    Stanford University, Yamaha, and others.

    Control Change Numbers:
       - Pickup Position = 4
       - String Sustain = 11
       - String Stretch = 1

    by Perry R. Cook and Gary P. Scavone, 1995 - 2005.
*/
/***************************************************/

#ifndef STK_STIFKARP_H
#define STK_STIFKARP_H

#include "Instrmnt.h"
#include "DelayL.h"
#include "DelayA.h"
#include "OneZero.h"
#include "Noise.h"
#include "BiQuad.h"

class StifKarp : public Instrmnt
{
 public:
  //! Class constructor, taking the lowest desired playing frequency.
  StifKarp(StkFloat lowestFrequency);

  //! Class destructor.
  ~StifKarp();

  //! Reset and clear all internal state.
  void clear();

  //! Set instrument parameters for a particular frequency.
  void setFrequency(StkFloat frequency);

  //! Set the stretch "factor" of the string (0.0 - 1.0).
  void setStretch(StkFloat stretch);

  //! Set the pluck or "excitation" position along the string (0.0 - 1.0).
  void setPickupPosition(StkFloat position);

  //! Set the base loop gain.
  /*!
    The actual loop gain is set according to the frequency.
    Because of high-frequency loop filter roll-off, higher
    frequency settings have greater loop gains.
  */
  void setBaseLoopGain(StkFloat aGain);

  //! Pluck the string with the given amplitude using the current frequency.
  void pluck(StkFloat amplitude);

  //! Start a note with the given frequency and amplitude.
  void noteOn(StkFloat frequency, StkFloat amplitude);

  //! Stop a note with the given amplitude (speed of decay).
  void noteOff(StkFloat amplitude);

  //! Perform the control change specified by \e number and \e value (0.0 - 128.0).
  void controlChange(int number, StkFloat value);

 protected:

  StkFloat computeSample( void );

  DelayA  delayLine_;
  DelayL  combDelay_;
  OneZero filter_;
  Noise   noise_;
  BiQuad  biquad_[4];

  unsigned long length_;
  StkFloat loopGain_;
  StkFloat baseLoopGain_;
  StkFloat lastFrequency_;
  StkFloat lastLength_;
  StkFloat stretching_;
  StkFloat pluckAmplitude_;
  StkFloat pickupPosition_;

};

#endif