/*******************************************/
/*  One Pole Filter Class,                 */
/*  by Perry R. Cook, 1995-96              */ 
/*  The parameter gain is an additional    */
/*  gain parameter applied to the filter   */  
/*  on top of the normalization that takes */
/*  place automatically.  So the net max   */
/*  gain through the system equals the     */
/*  value of gain.  sgain is the combina-  */
/*  tion of gain and the normalization     */
/*  parameter, so if you set the poleCoeff */
/*  to alpha, sgain is always set to       */
/*  gain * (1.0 - fabs(alpha)).            */
/*******************************************/

#include "OnePole.h"

OnePole :: OnePole() : Filter()
{
  poleCoeff = (MY_FLOAT) 0.9;
  gain = (MY_FLOAT) 1.0;
  sgain = (MY_FLOAT) 0.1;
  outputs = (MY_FLOAT *) malloc(sizeof(MY_FLOAT));
  outputs[0] = (MY_FLOAT) 0.0;
}

OnePole :: ~OnePole()    
{
  free(outputs);
}

void OnePole :: clear()
{
  outputs[0] = (MY_FLOAT) 0.0;
  lastOutput = (MY_FLOAT) 0.0;
}

void OnePole :: setPole(MY_FLOAT aValue)
{
  poleCoeff = aValue;
  if (poleCoeff > 0.0)                   // Normalize gain to 1.0 max
    sgain = gain * ((MY_FLOAT) 1.0 - poleCoeff);
  else
    sgain = gain * ((MY_FLOAT) 1.0 + poleCoeff);
}

void OnePole :: setGain(MY_FLOAT aValue)
{
  gain = aValue;
  if (poleCoeff > 0.0)        
    sgain = gain * ((MY_FLOAT) 1.0 - poleCoeff);  // Normalize gain to 1.0 max
  else
    sgain = gain * ((MY_FLOAT) 1.0 + poleCoeff);
}

MY_FLOAT OnePole :: tick(MY_FLOAT sample)  // Perform Filter Operation
{
  outputs[0] = (sgain * sample) + (poleCoeff * outputs[0]);              
  lastOutput = outputs[0];
  return lastOutput;
}