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/* taken and adapted from
* amSynth
* (c) 2001-2005 Nick Dowell
*
* amSynth was released under the GPL2 license, see COPYING.gpl2
*/
#ifndef __FILTER_H__
#define __FILTER_H__
#include "fixed.h"
/**
* A 24 dB/octave resonant low-pass filter.
**/
class LowPassFilter
{
public:
LowPassFilter();
/**
* Reset the filter - clear anything in the delay units of the filter.
*/
void reset();
void set_params(float fc, float res);
void process_sample(fixed_t* smp);
private:
float rate;
float nyquist;
double d1, d2, d3, d4;
double a0, a1, a2, b1, b2;
};
#endif
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