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////////////////////////////////////////////////////////////////////////
// This file is part of the SndObj library
//
// This program 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 2 of the License, or
// (at your option) any later version.
//
// 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 for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// Copyright (c)Victor Lazzarini, 1997-2004
// See License.txt for a disclaimer of all warranties
// and licensing information
//************************************************************//
// filter.h: interface of the Filter abstract base class //
// //
// //
// //
//************************************************************//
#ifndef _FILTER_H
#define _FILTER_H
#include "SndObj.h"
class Filter : public SndObj {
protected:
float m_fr;
float m_bw;
double* m_delay; // filter delay
void inline SetParam(float fr, float bw);
double m_a;
double m_b1;
double m_b2;
public:
Filter();
Filter(float fr, float bw, SndObj* inObj, int vecsize=DEF_VECSIZE, float sr=DEF_SR);
~Filter();
virtual void SetFreq(float fr);
virtual void SetBW(float bw);
int Set(char* mess, float value);
void SetSr(float sr){
m_sr = sr;
SetParam(m_fr, m_bw);
}
char* ErrorMessage();
short DoProcess();
};
void
Filter::SetParam(float fr, float bw){
double R, thecos, rsq, rr; // coefficient vars
rr = 2*(R = (1 - PI*(bw/m_sr)));
rsq = R*R;
thecos = (rr/(1+(rsq)))*cos(PI*(fr/(m_sr/2)));
m_a = (1 - (rsq))*sin(acos(thecos));
m_b1 = rr*thecos;
m_b2 = rsq;
}
#endif
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