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//===========================================================================
//
// DeicsOnze an emulator of the YAMAHA DX11 synthesizer
//
// Version 0.5.5
//
// deicsonzefilter.cpp
//
//
// Copyright (c) 2004-2006 Nil Geisweiller
//
//
//
// 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., 51 Franklin Street, Fifth Floor, Boston, MA
// 02111-1301, USA or point your web browser to http://www.gnu.org.
//===========================================================================
#include "deicsonzefilter.h"
LowFilter::LowFilter() {
_li = 0.0;
_ri = 0.0;
_lo = 0.0;
_ro = 0.0;
}
void LowFilter::setSamplerate(int sr) {
_samplerate = sr;
}
void LowFilter::setCutoff(double cut) {
_cutoff = cut;
float w = 2.0 * (float)_samplerate;
float fCut = _cutoff * 2.0 * M_PI;
float norm = 1.0 / (fCut + w);
_a = fCut * norm;
_b = (w - fCut) * norm;
}
void LowFilter::process(float* leftSamples, float* rightSamples, unsigned n) {
float cl, cr;
for(unsigned i = 0; i < n; i++) {
cl = leftSamples[i];
cr = rightSamples[i];
leftSamples[i] = _a * (cl + _li) + _b * _lo;
rightSamples[i] = _a * (cr + _ri) + _b * _ro;
_li = cl;
_ri = cr;
_lo = leftSamples[i];
_ro = rightSamples[i];
}
}
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