PitShift.h

#ifndef STK_PITSHIFT_H
#define STK_PITSHIFT_H
 
#include "Effect.h"
#include "DelayL.h"
 
namespace stk {
 
/***************************************************/
/***************************************************/
 
const int maxDelay = 5024;
 
class PitShift : public Effect
{
 public:
  PitShift( void );
 
  void clear( void );
 
  void setShift( StkFloat shift );
 
  StkFloat lastOut( void ) const { return lastFrame_[0]; };
 
  StkFloat tick( StkFloat input );
 
 
  StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
 
 
  StkFrames& tick( StkFrames& iFrames, StkFrames &oFrames, unsigned int iChannel = 0, unsigned int oChannel = 0 );
 
 protected:
 
  DelayL delayLine_;
  StkFloat delay_[2];
  StkFloat env_[2];
  StkFloat rate_;
  unsigned long delayLength_;
  unsigned long halfLength_;
 
};
 
inline StkFloat PitShift :: tick( StkFloat input )
{
  // Calculate the two delay length values, keeping them within the
  // range 12 to maxDelay-12.
  delay_[0] += rate_;
  while ( delay_[0] > maxDelay-12 ) delay_[0] -= delayLength_;
  while ( delay_[0] < 12 ) delay_[0] += delayLength_;
 
  delay_[1] = delay_[0] + halfLength_;
  while ( delay_[1] > maxDelay-12 ) delay_[1] -= delayLength_;
  while ( delay_[1] < 12 ) delay_[1] += delayLength_;
 
  // Set the new delay line lengths.
  delayLine_.setDelay( delay_[0] );
 
  // Calculate a triangular envelope.
  env_[1] = fabs( ( delay_[0] - halfLength_ + 12 ) * ( 1.0 / (halfLength_ + 12 ) ) );
  env_[0] = 1.0 - env_[1];
 
  // Delay input and apply envelope.
  lastFrame_[0] = env_[1] * delayLine_.tapOut( delay_[1] );
  lastFrame_[0] =  +env_[0] * delayLine_.tick( input );
 
  // Compute effect mix and output.
  lastFrame_[0] *= effectMix_;
  lastFrame_[0] += ( 1.0 - effectMix_ ) * input;
 
  return lastFrame_[0];
}
 
} // stk namespace
 
#endif