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https://github.com/thestk/stk
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120 lines
3.5 KiB
C++
120 lines
3.5 KiB
C++
/***************************************************/
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/*! \class NRev
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\brief CCRMA's NRev reverberator class.
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This class takes a monophonic input signal and produces a stereo
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output signal. It is derived from the CLM NRev function, which is
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based on the use of networks of simple allpass and comb delay
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filters. This particular arrangement consists of 6 comb filters
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in parallel, followed by 3 allpass filters, a lowpass filter, and
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another allpass in series, followed by two allpass filters in
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parallel with corresponding right and left outputs.
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by Perry R. Cook and Gary P. Scavone, 1995-2012.
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*/
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/***************************************************/
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#include "NRev.h"
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#include <cmath>
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namespace stk {
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NRev :: NRev( StkFloat T60 )
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{
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if ( T60 <= 0.0 ) {
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oStream_ << "NRev::NRev: 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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int lengths[15] = {1433, 1601, 1867, 2053, 2251, 2399, 347, 113, 37, 59, 53, 43, 37, 29, 19};
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double scaler = Stk::sampleRate() / 25641.0;
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int delay, i;
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for ( i=0; i<15; 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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for ( i=0; i<6; i++ ) {
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combDelays_[i].setMaximumDelay( lengths[i] );
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combDelays_[i].setDelay( lengths[i] );
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combCoefficient_[i] = pow(10.0, (-3 * lengths[i] / (T60 * Stk::sampleRate())));
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}
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for ( i=0; i<8; i++ ) {
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allpassDelays_[i].setMaximumDelay( lengths[i+6] );
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allpassDelays_[i].setDelay( lengths[i+6] );
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}
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this->setT60( T60 );
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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 NRev :: clear()
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{
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int i;
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for (i=0; i<6; i++) combDelays_[i].clear();
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for (i=0; i<8; i++) allpassDelays_[i].clear();
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lastFrame_[0] = 0.0;
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lastFrame_[1] = 0.0;
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lowpassState_ = 0.0;
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}
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void NRev :: setT60( StkFloat T60 )
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{
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if ( T60 <= 0.0 ) {
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oStream_ << "NRev::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<6; 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& NRev :: 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_ << "NRev::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& NRev :: 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_ << "NRev::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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