mirror of
https://github.com/thestk/stk
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138 lines
3.9 KiB
C++
138 lines
3.9 KiB
C++
/***************************************************/
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/*! \class JCRev
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\brief John Chowning's reverberator class.
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This class takes a monophonic input signal and
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produces a stereo output signal. It is derived
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from the CLM JCRev function, which is based on
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the use of networks of simple allpass and comb
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delay filters. This class implements three
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series allpass units, followed by four parallel
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comb filters, and two decorrelation delay lines
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in parallel at the output.
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Although not in the original JC reverberator,
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one-pole lowpass filters have been added inside
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the feedback comb filters.
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by Perry R. Cook and Gary P. Scavone, 1995-2011.
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*/
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/***************************************************/
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#include "JCRev.h"
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#include <cmath>
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namespace stk {
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JCRev :: JCRev( StkFloat T60 )
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{
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if ( T60 <= 0.0 ) {
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oStream_ << "JCRev::JCRev: argument (" << T60 << ") must be positive!";
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handleError( StkError::FUNCTION_ARGUMENT );
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}
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lastFrame_.resize( 1, 2, 0.0 ); // resize lastFrame_ for stereo output
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// Delay lengths for 44100 Hz sample rate.
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// {1116, 1188, 1356, 1277, 1422, 1491, 1617, 1557} // FreeVerb comb delays
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int lengths[9] = {1116, 1356, 1422, 1617, 225, 341, 441, 211, 179};
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double scaler = Stk::sampleRate() / 44100.0;
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int delay, i;
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if ( scaler != 1.0 ) {
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for ( i=0; i<9; i++ ) {
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delay = (int) floor( scaler * lengths[i] );
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if ( (delay & 1) == 0) delay++;
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while ( !this->isPrime(delay) ) delay += 2;
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lengths[i] = delay;
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}
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}
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for ( i=0; i<3; i++ ) {
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allpassDelays_[i].setMaximumDelay( lengths[i+4] );
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allpassDelays_[i].setDelay( lengths[i+4] );
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}
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for ( i=0; i<4; i++ ) {
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combDelays_[i].setMaximumDelay( lengths[i] );
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combDelays_[i].setDelay( lengths[i] );
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combFilters_[i].setPole( 0.2 );
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}
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this->setT60( T60 );
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outLeftDelay_.setMaximumDelay( lengths[7] );
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outLeftDelay_.setDelay( lengths[7] );
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outRightDelay_.setMaximumDelay( lengths[8] );
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outRightDelay_.setDelay( lengths[8] );
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allpassCoefficient_ = 0.7;
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effectMix_ = 0.3;
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this->clear();
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}
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void JCRev :: clear()
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{
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allpassDelays_[0].clear();
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allpassDelays_[1].clear();
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allpassDelays_[2].clear();
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combDelays_[0].clear();
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combDelays_[1].clear();
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combDelays_[2].clear();
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combDelays_[3].clear();
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outRightDelay_.clear();
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outLeftDelay_.clear();
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lastFrame_[0] = 0.0;
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lastFrame_[1] = 0.0;
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}
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void JCRev :: setT60( StkFloat T60 )
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{
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if ( T60 <= 0.0 ) {
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oStream_ << "JCRev::setT60: argument (" << T60 << ") must be positive!";
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handleError( StkError::WARNING ); return;
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}
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for ( int i=0; i<4; i++ )
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combCoefficient_[i] = pow(10.0, (-3.0 * combDelays_[i].getDelay() / (T60 * Stk::sampleRate())));
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}
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StkFrames& JCRev :: tick( StkFrames& frames, unsigned int channel )
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{
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#if defined(_STK_DEBUG_)
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if ( channel >= frames.channels() - 1 ) {
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oStream_ << "JCRev::tick(): channel and StkFrames arguments are incompatible!";
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handleError( StkError::FUNCTION_ARGUMENT );
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}
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#endif
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StkFloat *samples = &frames[channel];
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unsigned int hop = frames.channels();
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for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
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*samples = tick( *samples );
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*(samples+1) = lastFrame_[1];
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}
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return frames;
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}
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StkFrames& JCRev :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
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{
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#if defined(_STK_DEBUG_)
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if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() - 1 ) {
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oStream_ << "JCRev::tick(): channel and StkFrames arguments are incompatible!";
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handleError( StkError::FUNCTION_ARGUMENT );
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}
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#endif
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StkFloat *iSamples = &iFrames[iChannel];
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StkFloat *oSamples = &oFrames[oChannel];
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unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
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for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
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*oSamples = tick( *iSamples );
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*(oSamples+1) = lastFrame_[1];
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}
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return iFrames;
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}
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} // stk namespace
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