/***************************************************/
/*! \class BiQuad
    \brief STK biquad (two-pole, two-zero) filter class.

    This protected Filter subclass implements a
    two-pole, two-zero digital filter.  A method
    is provided for creating a resonance in the
    frequency response while maintaining a constant
    filter gain.

    by Perry R. Cook and Gary P. Scavone, 1995 - 2002.
*/
/***************************************************/

#if !defined(__BIQUAD_H)
#define __BIQUAD_H

#include "Filter.h"

class BiQuad : protected Filter
{
public:

  //! Default constructor creates a second-order pass-through filter.
  BiQuad();

  //! Class destructor.
  virtual ~BiQuad();

  //! Clears all internal states of the filter.
  void clear(void);

  //! Set the b[0] coefficient value.
  void setB0(MY_FLOAT b0);

  //! Set the b[1] coefficient value.
  void setB1(MY_FLOAT b1);

  //! Set the b[2] coefficient value.
  void setB2(MY_FLOAT b2);

  //! Set the a[1] coefficient value.
  void setA1(MY_FLOAT a1);

  //! Set the a[2] coefficient value.
  void setA2(MY_FLOAT a2);

  //! Sets the filter coefficients for a resonance at \e frequency (in Hz).
  /*!
    This method determines the filter coefficients corresponding to
    two complex-conjugate poles with the given \e frequency (in Hz)
    and \e radius from the z-plane origin.  If \e normalize is true,
    the filter zeros are placed at z = 1, z = -1, and the coefficients
    are then normalized to produce a constant unity peak gain
    (independent of the filter \e gain parameter).  The resulting
    filter frequency response has a resonance at the given \e
    frequency.  The closer the poles are to the unit-circle (\e radius
    close to one), the narrower the resulting resonance width.
  */
  void setResonance(MY_FLOAT frequency, MY_FLOAT radius, bool normalize = FALSE);

  //! Set the filter coefficients for a notch at \e frequency (in Hz).
  /*!
    This method determines the filter coefficients corresponding to
    two complex-conjugate zeros with the given \e frequency (in Hz)
    and \e radius from the z-plane origin.  No filter normalization
    is attempted.
  */
  void setNotch(MY_FLOAT frequency, MY_FLOAT radius);

  //! Sets the filter zeroes for equal resonance gain.
  /*!
    When using the filter as a resonator, zeroes places at z = 1, z
    = -1 will result in a constant gain at resonance of 1 / (1 - R),
    where R is the pole radius setting.

  */
  void setEqualGainZeroes();

  //! Set the filter gain.
  /*!
    The gain is applied at the filter input and does not affect the
    coefficient values.  The default gain value is 1.0.
   */
  void setGain(MY_FLOAT theGain);

  //! Return the current filter gain.
  MY_FLOAT getGain(void) const;

  //! Return the last computed output value.
  MY_FLOAT lastOut(void) const;

  //! Input one sample to the filter and return one output.
  MY_FLOAT tick(MY_FLOAT sample);

  //! Input \e vectorSize samples to the filter and return an equal number of outputs in \e vector.
  MY_FLOAT *tick(MY_FLOAT *vector, unsigned int vectorSize);
};

#endif