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JetTable.h

00001 #ifndef STK_JETTABL_H
00002 #define STK_JETTABL_H
00003 
00004 #include "Function.h"
00005 
00006 namespace stk {
00007 
00008 /***************************************************/
00021 /***************************************************/
00022 
00023 class JetTable : public Function
00024 {
00025 public:
00026 
00028   StkFloat tick( StkFloat input );
00029 
00031 
00039   StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
00040 
00042 
00050   StkFrames& tick( StkFrames& iFrames, StkFrames &oFrames, unsigned int iChannel = 0, unsigned int oChannel = 0 );
00051 
00052 };
00053 
00054 inline StkFloat JetTable :: tick( StkFloat input )
00055 {
00056   // Perform "table lookup" using a polynomial
00057   // calculation (x^3 - x), which approximates
00058   // the jet sigmoid behavior.
00059   lastFrame_[0] = input * (input * input - 1.0);
00060 
00061   // Saturate at +/- 1.0.
00062   if ( lastFrame_[0] > 1.0 ) lastFrame_[0] = 1.0;
00063   if ( lastFrame_[0] < -1.0 ) lastFrame_[0] = -1.0; 
00064   return lastFrame_[0];
00065 }
00066 
00067 inline StkFrames& JetTable :: tick( StkFrames& frames, unsigned int channel )
00068 {
00069 #if defined(_STK_DEBUG_)
00070   if ( channel >= frames.channels() ) {
00071     errorString_ << "JetTable::tick(): channel and StkFrames arguments are incompatible!";
00072     handleError( StkError::FUNCTION_ARGUMENT );
00073   }
00074 #endif
00075 
00076   StkFloat *samples = &frames[channel];
00077   unsigned int hop = frames.channels();
00078   for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
00079     *samples = *samples * (*samples * *samples - 1.0);
00080     if ( *samples > 1.0) *samples = 1.0;
00081     if ( *samples < -1.0) *samples = -1.0;
00082   }
00083 
00084   lastFrame_[0] = *(samples-hop);
00085   return frames;
00086 }
00087 
00088 inline StkFrames& JetTable :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
00089 {
00090 #if defined(_STK_DEBUG_)
00091   if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
00092     errorString_ << "JetTable::tick(): channel and StkFrames arguments are incompatible!";
00093     handleError( StkError::FUNCTION_ARGUMENT );
00094   }
00095 #endif
00096 
00097   StkFloat *iSamples = &iFrames[iChannel];
00098   StkFloat *oSamples = &oFrames[oChannel];
00099   unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
00100   for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
00101     *oSamples = *oSamples * (*oSamples * *oSamples - 1.0);
00102     if ( *oSamples > 1.0) *oSamples = 1.0;
00103     if ( *oSamples < -1.0) *oSamples = -1.0;
00104   }
00105 
00106   lastFrame_[0] = *(oSamples-oHop);
00107   return iFrames;
00108 }
00109 
00110 } // stk namespace
00111 
00112 #endif

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