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tdemultimedia/arts/modules/synth/synth_shelve_cutoff_impl.cpp

72 lines
2.0 KiB

/*
Copyright (C) 2000 Stefan Westerfeld
stefan@space.twc.de
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include "artsmodulessynth.h"
#include "stdsynthmodule.h"
#include "c_filter_stuff.h"
using namespace Arts;
class Synth_SHELVE_CUTOFF_impl : virtual public Synth_SHELVE_CUTOFF_skel,
virtual public StdSynthModule
{
protected:
filter f;
public:
void streamInit();
void calculateBlock(unsigned long samples);
};
REGISTER_IMPLEMENTATION(Synth_SHELVE_CUTOFF_impl);
void Synth_SHELVE_CUTOFF_impl::streamInit()
{
initfilter(&f);
}
void Synth_SHELVE_CUTOFF_impl::calculateBlock(unsigned long samples)
{
float filterfrequency = frequency[0];
// the shelve-lowpass-filter is extremely sensitive to frequencies which
// are out of it's range (it produces NaN's then) so we'll be careful ;)
if(filterfrequency > 22000.0) filterfrequency = 22000.0;
if(filterfrequency < 1.0) filterfrequency = 1.0;
setfilter_shelvelowpass(&f,filterfrequency,80.0);
unsigned long i;
for(i=0;i<samples;i++)
{
// better paste applyfilter here instead of:
// *outsig++ = 0.95 * applyfilter(&f,*insig++);
f.x = invalue[i];
f.y = f.cx * f.x + f.cx1 * f.x1 + f.cx2 * f.x2
+ f.cy1 * f.y1 + f.cy2 * f.y2;
f.x2 = f.x1;
f.x1 = f.x;
f.y2 = f.y1;
f.y1 = f.y;
outvalue[i] = 0.95 * f.y;
}
}