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# BiQuad.h

    00001 #ifndef STK_BIQUAD_H
    00002 #define STK_BIQUAD_H
    00003
    00004 #include "Filter.h"
    00005
    00006 namespace stk {
    00007
    00008 /***************************************************/
    00018 /***************************************************/
    00019
    00020 class BiQuad : public Filter
    00021 {
    00022 public:
    00023
    00025   BiQuad();
    00026
    00028   ~BiQuad();
    00029
    00031   void ignoreSampleRateChange( bool ignore = true ) { ignoreSampleRateChange_ = ignore; };
    00032
    00034   void setCoefficients( StkFloat b0, StkFloat b1, StkFloat b2, StkFloat a1, StkFloat a2, bool clearState = false );
    00035
    00037   void setB0( StkFloat b0 ) { b_[0] = b0; };
    00038
    00040   void setB1( StkFloat b1 ) { b_[1] = b1; };
    00041
    00043   void setB2( StkFloat b2 ) { b_[2] = b2; };
    00044
    00046   void setA1( StkFloat a1 ) { a_[1] = a1; };
    00047
    00049   void setA2( StkFloat a2 ) { a_[2] = a2; };
    00050
    00052
    00065   void setResonance( StkFloat frequency, StkFloat radius, bool normalize = false );
    00066
    00068
    00075   void setNotch( StkFloat frequency, StkFloat radius );
    00076
    00078
    00084   void setEqualGainZeroes( void );
    00085
    00087   StkFloat lastOut( void ) const { return lastFrame_[0]; };
    00088
    00090   StkFloat tick( StkFloat input );
    00091
    00093
    00101   StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
    00102
    00104
    00112   StkFrames& tick( StkFrames& iFrames, StkFrames &oFrames, unsigned int iChannel = 0, unsigned int oChannel = 0 );
    00113
    00114  protected:
    00115
    00116   virtual void sampleRateChanged( StkFloat newRate, StkFloat oldRate );
    00117 };
    00118
    00119 inline StkFloat BiQuad :: tick( StkFloat input )
    00120 {
    00121   inputs_[0] = gain_ * input;
    00122   lastFrame_[0] = b_[0] * inputs_[0] + b_[1] * inputs_[1] + b_[2] * inputs_[2];
    00123   lastFrame_[0] -= a_[2] * outputs_[2] + a_[1] * outputs_[1];
    00124   inputs_[2] = inputs_[1];
    00125   inputs_[1] = inputs_[0];
    00126   outputs_[2] = outputs_[1];
    00127   outputs_[1] = lastFrame_[0];
    00128
    00129   return lastFrame_[0];
    00130 }
    00131
    00132 inline StkFrames& BiQuad :: tick( StkFrames& frames, unsigned int channel )
    00133 {
    00134 #if defined(_STK_DEBUG_)
    00135   if ( channel >= frames.channels() ) {
    00136     oStream_ << "BiQuad::tick(): channel and StkFrames arguments are incompatible!";
    00137     handleError( StkError::FUNCTION_ARGUMENT );
    00138   }
    00139 #endif
    00140
    00141   StkFloat *samples = &frames[channel];
    00142   unsigned int hop = frames.channels();
    00143   for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
    00144     inputs_[0] = gain_ * *samples;
    00145     *samples = b_[0] * inputs_[0] + b_[1] * inputs_[1] + b_[2] * inputs_[2];
    00146     *samples -= a_[2] * outputs_[2] + a_[1] * outputs_[1];
    00147     inputs_[2] = inputs_[1];
    00148     inputs_[1] = inputs_[0];
    00149     outputs_[2] = outputs_[1];
    00150     outputs_[1] = *samples;
    00151   }
    00152
    00153   lastFrame_[0] = outputs_[1];
    00154   return frames;
    00155 }
    00156
    00157 inline StkFrames& BiQuad :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
    00158 {
    00159 #if defined(_STK_DEBUG_)
    00160   if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
    00161     oStream_ << "BiQuad::tick(): channel and StkFrames arguments are incompatible!";
    00162     handleError( StkError::FUNCTION_ARGUMENT );
    00163   }
    00164 #endif
    00165
    00166   StkFloat *iSamples = &iFrames[iChannel];
    00167   StkFloat *oSamples = &oFrames[oChannel];
    00168   unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
    00169   for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
    00170     inputs_[0] = gain_ * *iSamples;
    00171     *oSamples = b_[0] * inputs_[0] + b_[1] * inputs_[1] + b_[2] * inputs_[2];
    00172     *oSamples -= a_[2] * outputs_[2] + a_[1] * outputs_[1];
    00173     inputs_[2] = inputs_[1];
    00174     inputs_[1] = inputs_[0];
    00175     outputs_[2] = outputs_[1];
    00176     outputs_[1] = *oSamples;
    00177   }
    00178
    00179   lastFrame_[0] = outputs_[1];
    00180   return iFrames;
    00181 }
    00182
    00183 } // stk namespace
    00184
    00185 #endif
    00186

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