mirror of
https://github.com/thestk/stk
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87 lines
2.4 KiB
C++
87 lines
2.4 KiB
C++
#ifndef STK_FILTER_H
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#define STK_FILTER_H
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#include "Stk.h"
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#include <vector>
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namespace stk {
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/***************************************************/
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/*! \class Filter
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\brief STK abstract filter class.
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This class provides limited common functionality for STK digital
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filter subclasses. It is general enough to support both
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monophonic and polyphonic input/output classes.
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by Perry R. Cook and Gary P. Scavone, 1995 - 2010.
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*/
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/***************************************************/
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class Filter : public Stk
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{
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public:
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//! Class constructor.
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Filter( void ) { gain_ = 1.0; channelsIn_ = 1; lastFrame_.resize( 1, 1, 0.0 ); };
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//! Return the number of input channels for the class.
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unsigned int channelsIn( void ) const { return channelsIn_; };
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//! Return the number of output channels for the class.
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unsigned int channelsOut( void ) const { return lastFrame_.channels(); };
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//! Clears all internal states of the filter.
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virtual void clear( void );
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//! Set the filter gain.
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/*!
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The gain is applied at the filter input and does not affect the
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coefficient values. The default gain value is 1.0.
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*/
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void setGain( StkFloat gain ) { gain_ = gain; };
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//! Return the current filter gain.
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StkFloat getGain( void ) const { return gain_; };
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//! Return an StkFrames reference to the last output sample frame.
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const StkFrames& lastFrame( void ) const { return lastFrame_; };
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//! Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.
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/*!
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The StkFrames argument reference is returned. The \c channel
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argument must be less than the number of channels in the
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StkFrames argument (the first channel is specified by 0).
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However, range checking is only performed if _STK_DEBUG_ is
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defined during compilation, in which case an out-of-range value
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will trigger an StkError exception.
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*/
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virtual StkFrames& tick( StkFrames& frames, unsigned int channel = 0 ) = 0;
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protected:
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unsigned int channelsIn_;
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StkFrames lastFrame_;
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StkFloat gain_;
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std::vector<StkFloat> b_;
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std::vector<StkFloat> a_;
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StkFrames outputs_;
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StkFrames inputs_;
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};
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inline void Filter :: clear( void )
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{
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unsigned int i;
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for ( i=0; i<inputs_.size(); i++ )
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inputs_[i] = 0.0;
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for ( i=0; i<outputs_.size(); i++ )
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outputs_[i] = 0.0;
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for ( i=0; i<lastFrame_.size(); i++ )
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lastFrame_[i] = 0.0;
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}
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} // stk namespace
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#endif
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