JetTable.h

#ifndef STK_JETTABL_H
#define STK_JETTABL_H
 
#include "Function.h"
 
namespace stk {
 
/***************************************************/
/***************************************************/
 
class JetTable : public Function
{
public:
 
  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 );
 
};
 
inline StkFloat JetTable :: tick( StkFloat input )
{
  // Perform "table lookup" using a polynomial
  // calculation (x^3 - x), which approximates
  // the jet sigmoid behavior.
  lastFrame_[0] = input * (input * input - 1.0);
 
  // Saturate at +/- 1.0.
  if ( lastFrame_[0] > 1.0 ) lastFrame_[0] = 1.0;
  if ( lastFrame_[0] < -1.0 ) lastFrame_[0] = -1.0; 
  return lastFrame_[0];
}
 
inline StkFrames& JetTable :: tick( StkFrames& frames, unsigned int channel )
{
#if defined(_STK_DEBUG_)
  if ( channel >= frames.channels() ) {
    oStream_ << "JetTable::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  StkFloat *samples = &frames[channel];
  unsigned int hop = frames.channels();
  for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
    *samples = *samples * (*samples * *samples - 1.0);
    if ( *samples > 1.0) *samples = 1.0;
    if ( *samples < -1.0) *samples = -1.0;
  }
 
  lastFrame_[0] = *(samples-hop);
  return frames;
}
 
inline StkFrames& JetTable :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
{
#if defined(_STK_DEBUG_)
  if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
    oStream_ << "JetTable::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  StkFloat *iSamples = &iFrames[iChannel];
  StkFloat *oSamples = &oFrames[oChannel];
  unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
  for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
    *oSamples = *oSamples * (*oSamples * *oSamples - 1.0);
    if ( *oSamples > 1.0) *oSamples = 1.0;
    if ( *oSamples < -1.0) *oSamples = -1.0;
  }
 
  lastFrame_[0] = *(oSamples-oHop);
  return iFrames;
}
 
} // stk namespace
 
#endif