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tdemultimedia/arts/modules/synth/synth_rc_impl.cc

111 lines
2.6 KiB

/*
Copyright (C) 2000 Jeff Tranter
tranter@pobox.com
(C) 1999 Stefan Westerfeld
stefan@space.twc.de
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 02110-1301, USA.
*/
#include <math.h>
#include "artsmodulessynth.h"
#include "stdsynthmodule.h"
using namespace Arts;
class Synth_RC_impl : virtual public Synth_RC_skel,
virtual public StdSynthModule
{
protected:
float _b, _f;
float B, dB;
float F, dF, oF, oU, U, Fsoll, Bsoll;
float oldvalue;
public:
float b() { return _b; }
void b(float newB) { _b = newB; }
float f() { return _f; }
void f(float newF) { _f = newF; }
void streamInit()
{
oldvalue = 0;
B = 0;
F = 0; oF = 0;
U = 0; oU = 0;
}
void calculateBlock(unsigned long samples)
{
unsigned long i, hits;
const float zero_lower = -0.00000001;
const float zero_upper = 0.00000001;
if (zero_lower < invalue[0] && invalue[0] < zero_upper)
{
/* for comments see equalizer.cc/Synth_STD_EQUALIZER implementation */
/*
* This implementation differs from the implementation there,
* because it is done as a kind of powersafing. If no input is
* found, then no output is generated.
*/
if (zero_lower < oldvalue && oldvalue < zero_upper)
{
oldvalue = 0.0;
B = 0.0;
F = 0.0; oF = 0.0;
U = 0.0; oU = 0.0;
hits = 0;
for (i=0; i<samples; i++)
{
if (zero_lower < invalue[i] && invalue[i] < zero_upper)
{
// try to zero out the whole block
outvalue[i] = 0.0;
hits++;
}
}
if (hits == samples) return;
}
}
for (i=0; i<samples; i++)
{
B = B + (invalue[i] - oldvalue); /* input into RC */
oldvalue = invalue[i];
Bsoll = U - oU;
oU = U;
dB = (Bsoll - B) / _b;
B += dB;
U -= dB;
Fsoll = U;
dF = (Fsoll - F) / _f;
F += dF; /* Energie dF wird ins Feld uebertragen */
U -= dF;
outvalue[i] = (F - oF) * (_b + _f);
oF = F;
}
}
};
REGISTER_IMPLEMENTATION(Synth_RC_impl);