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DelayA.h

00001 #ifndef STK_DELAYA_H
00002 #define STK_DELAYA_H
00003 
00004 #include "Filter.h"
00005 
00006 namespace stk {
00007 
00008 /***************************************************/
00026 /***************************************************/
00027 
00028 class DelayA : public Filter
00029 {
00030 public:
00031 
00033 
00038   DelayA( StkFloat delay = 0.5, unsigned long maxDelay = 4095 );
00039 
00041   ~DelayA();
00042 
00044   void clear( void );
00045   
00047 
00054   void setMaximumDelay( unsigned long delay );
00055 
00057 
00060   void setDelay( StkFloat delay );
00061 
00063   StkFloat getDelay( void ) const { return delay_; };
00064 
00066 
00071   StkFloat contentsAt( unsigned long tapDelay );
00072 
00074   StkFloat lastOut( void ) const { return lastFrame_[0]; };
00075 
00077 
00080   StkFloat nextOut( void );
00081 
00083   StkFloat tick( StkFloat input );
00084 
00086 
00094   StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
00095 
00097 
00105   StkFrames& tick( StkFrames& iFrames, StkFrames &oFrames, unsigned int iChannel = 0, unsigned int oChannel = 0 );
00106 
00107 protected:  
00108 
00109   unsigned long inPoint_;
00110   unsigned long outPoint_;
00111   StkFloat delay_;
00112   StkFloat alpha_;
00113   StkFloat coeff_;
00114   StkFloat apInput_;
00115   StkFloat nextOutput_;
00116   bool doNextOut_;
00117 };
00118 
00119 inline StkFloat DelayA :: nextOut( void )
00120 {
00121   if ( doNextOut_ ) {
00122     // Do allpass interpolation delay.
00123     nextOutput_ = -coeff_ * lastFrame_[0];
00124     nextOutput_ += apInput_ + ( coeff_ * inputs_[outPoint_] );
00125     doNextOut_ = false;
00126   }
00127 
00128   return nextOutput_;
00129 }
00130 
00131 inline StkFloat DelayA :: tick( StkFloat input )
00132 {
00133   inputs_[inPoint_++] = input * gain_;
00134 
00135   // Increment input pointer modulo length.
00136   if ( inPoint_ == inputs_.size() )
00137     inPoint_ = 0;
00138 
00139   lastFrame_[0] = nextOut();
00140   doNextOut_ = true;
00141 
00142   // Save the allpass input and increment modulo length.
00143   apInput_ = inputs_[outPoint_++];
00144   if ( outPoint_ == inputs_.size() )
00145     outPoint_ = 0;
00146 
00147   return lastFrame_[0];
00148 }
00149 
00150 inline StkFrames& DelayA :: tick( StkFrames& frames, unsigned int channel )
00151 {
00152 #if defined(_STK_DEBUG_)
00153   if ( channel >= frames.channels() ) {
00154     errorString_ << "DelayA::tick(): channel and StkFrames arguments are incompatible!";
00155     handleError( StkError::FUNCTION_ARGUMENT );
00156   }
00157 #endif
00158 
00159   StkFloat *samples = &frames[channel];
00160   unsigned int hop = frames.channels();
00161   for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
00162     inputs_[inPoint_++] = *samples * gain_;
00163     if ( inPoint_ == inputs_.size() ) inPoint_ = 0;
00164     *samples = nextOut();
00165     lastFrame_[0] = *samples;
00166     doNextOut_ = true;
00167     apInput_ = inputs_[outPoint_++];
00168     if ( outPoint_ == inputs_.size() ) outPoint_ = 0;
00169   }
00170 
00171   return frames;
00172 }
00173 
00174 inline StkFrames& DelayA :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
00175 {
00176 #if defined(_STK_DEBUG_)
00177   if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
00178     errorString_ << "DelayA::tick(): channel and StkFrames arguments are incompatible!";
00179     handleError( StkError::FUNCTION_ARGUMENT );
00180   }
00181 #endif
00182 
00183   StkFloat *iSamples = &iFrames[iChannel];
00184   StkFloat *oSamples = &oFrames[oChannel];
00185   unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
00186   for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
00187     inputs_[inPoint_++] = *iSamples * gain_;
00188     if ( inPoint_ == inputs_.size() ) inPoint_ = 0;
00189     *oSamples = nextOut();
00190     lastFrame_[0] = *oSamples;
00191     doNextOut_ = true;
00192     apInput_ = inputs_[outPoint_++];
00193     if ( outPoint_ == inputs_.size() ) outPoint_ = 0;
00194   }
00195 
00196   return iFrames;
00197 }
00198 
00199 } // stk namespace
00200 
00201 #endif

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