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/*
Copyright (C) 2010-2012 Florian Jung
This file is part of flo's FM synth.
flo's FM synth is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
flo's FM synth is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with flo's FM synth. If not, see <http://www.gnu.org/licenses/>.
*/
#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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