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/*
ZynAddSubFX - a software synthesizer
SV Filter.h - Several state-variable filters
Copyright (C) 2002-2005 Nasca Octavian Paul
Author: Nasca Octavian Paul
This program is free software; you can redistribute it and/or modify
it under the terms of version 2 of the GNU General Public License
as published by the Free Software Foundation.
This program 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 (version 2) for more details.
You should have received a copy of the GNU General Public License (version 2)
along with this program; if not, write to the Free Software Foundation,
Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef SV_FILTER_H
#define SV_FILTER_H
#include "../globals.h"
#include "Filter_.h"
class SVFilter:public Filter_{
public:
SVFilter(unsigned char Ftype,REALTYPE Ffreq, REALTYPE Fq,unsigned char Fstages);
~SVFilter();
void filterout(REALTYPE *smp);
void setfreq(REALTYPE frequency);
void setfreq_and_q(REALTYPE frequency,REALTYPE q_);
void setq(REALTYPE q_);
void settype(int type_);
void setgain(REALTYPE dBgain);
void setstages(int stages_);
void cleanup();
private:
struct fstage{
REALTYPE low,high,band,notch;
} st[MAX_FILTER_STAGES+1];
struct parameters{
REALTYPE f,q,q_sqrt;
}par,ipar;
void singlefilterout(REALTYPE *smp,fstage &x,parameters &par);
void computefiltercoefs();
int type;//The type of the filter (LPF1,HPF1,LPF2,HPF2...)
int stages;//how many times the filter is applied (0->1,1->2,etc.)
REALTYPE freq;//Frequency given in Hz
REALTYPE q; //Q factor (resonance or Q factor)
REALTYPE gain;//the gain of the filter (if are shelf/peak) filters
int abovenq;//this is 1 if the frequency is above the nyquist
int oldabovenq;
int needsinterpolation,firsttime;
};
#endif
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