/***************************************************/
/*! \class Mesh2D
    \brief Two-dimensional rectilinear waveguide mesh class.

    This class implements a rectilinear,
    two-dimensional digital waveguide mesh
    structure.  For details, see Van Duyne and
    Smith, "Physical Modeling with the 2-D Digital
    Waveguide Mesh", Proceedings of the 1993
    International Computer Music Conference.

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

    Control Change Numbers: 
       - X Dimension = 2
       - Y Dimension = 4
       - Mesh Decay = 11
       - X-Y Input Position = 1

    by Julius Smith, 2000 - 2002.
    Revised by Gary Scavone for STK, 2002.
*/
/***************************************************/

#ifndef STK_MESH2D_H
#define STK_MESH2D_H

#include "Instrmnt.h"
#include "OnePole.h"

const short NXMAX = 12;
const short NYMAX = 12;

class Mesh2D : public Instrmnt
{
 public:
  //! Class constructor, taking the x and y dimensions in samples.
  Mesh2D(short nX, short nY);

  //! Class destructor.
  ~Mesh2D();

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

  //! Set the x dimension size in samples.
  void setNX(short lenX);

  //! Set the y dimension size in samples.
  void setNY(short lenY);

  //! Set the x, y input position on a 0.0 - 1.0 scale.
  void setInputPosition(StkFloat xFactor, StkFloat yFactor);

  //! Set the loss filters gains (0.0 - 1.0).
  void setDecay(StkFloat decayFactor);

  //! Impulse the mesh with the given amplitude (frequency ignored).
  void noteOn(StkFloat frequency, StkFloat amplitude);

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

  //! Calculate and return the signal energy stored in the mesh.
  StkFloat energy();

  //! Input a sample to the mesh and compute one output sample.
  StkFloat inputTick( StkFloat input );

  //! 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 );

  StkFloat tick0();
  StkFloat tick1();
  void clearMesh();

  short NX_, NY_;
  short xInput_, yInput_;
  OnePole  filterX_[NXMAX];
  OnePole  filterY_[NYMAX];
  StkFloat v_[NXMAX-1][NYMAX-1]; // junction velocities
  StkFloat vxp_[NXMAX][NYMAX];   // positive-x velocity wave
  StkFloat vxm_[NXMAX][NYMAX];   // negative-x velocity wave
  StkFloat vyp_[NXMAX][NYMAX];   // positive-y velocity wave
  StkFloat vym_[NXMAX][NYMAX];   // negative-y velocity wave

  // Alternate buffers
  StkFloat vxp1_[NXMAX][NYMAX];  // positive-x velocity wave
  StkFloat vxm1_[NXMAX][NYMAX];  // negative-x velocity wave
  StkFloat vyp1_[NXMAX][NYMAX];  // positive-y velocity wave
  StkFloat vym1_[NXMAX][NYMAX];  // negative-y velocity wave

  int counter_; // time in samples
};

#endif