/***************************************************/
/*! \class FMVoices
    \brief STK singing FM synthesis instrument.

    This class implements 3 carriers and a common
    modulator, also referred to as algorithm 6 of
    the TX81Z.

    \code
    Algorithm 6 is :
                        /->1 -\
                     4-|-->2 - +-> Out
                        \->3 -/
    \endcode

    Control Change Numbers: 
       - Vowel = 2
       - Spectral Tilt = 4
       - LFO Speed = 11
       - LFO Depth = 1
       - ADSR 2 & 4 Target = 128

    The basic Chowning/Stanford FM patent expired
    in 1995, but there exist follow-on patents,
    mostly assigned to Yamaha.  If you are of the
    type who should worry about this (making
    money) worry away.

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

#ifndef STK_FMVOICES_H
#define STK_FMVOICES_H

#include "FM.h"

class FMVoices : public FM
{
 public:
  //! Class constructor.
  /*!
    An StkError will be thrown if the rawwave path is incorrectly set.
  */
  FMVoices();

  //! Class destructor.
  ~FMVoices();

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

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

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

 protected:

  StkFloat computeSample( void );

  int currentVowel_;
  StkFloat tilt_[3];
  StkFloat mods_[3];
};

#endif