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/*
Copyright (C) 2000 Stefan Westerfeld
[email protected]
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 "debug.h"
#include "stdsynthmodule.h"
using namespace Arts;
class Synth_ENVELOPE_ADSR_impl : virtual public Synth_ENVELOPE_ADSR_skel,
virtual public StdSynthModule
{
protected:
enum { NOOUT, ATTACK, SUSTAIN, DECAY, RELEASE } currentphase;
float level,increment,decrement;
public:
void streamInit()
{
currentphase = NOOUT;
level = 0;
}
void calculateBlock(unsigned long samples);
};
void Synth_ENVELOPE_ADSR_impl::calculateBlock(unsigned long samples)
{
/* FIXME:
* should be rewritten as generic envelope, would certainly
* be faster & more flexible
*/
unsigned long i;
for(i=0;i<samples;i++)
{
done[i] = 0;
if(active[i] < 0.5)
{
if(currentphase == NOOUT)
{
level = 0;
done[i] = 1;
}
else
{
if(currentphase != RELEASE) {
artsdebug("ADSR: entering release phase\n");
currentphase = RELEASE;
decrement = level / (release[i] * samplingRateFloat);
}
level -= decrement;
if(level <= 0)
{
level = 0;
currentphase = NOOUT;
}
}
}
else
{
switch(currentphase)
{
//quickly kill the note that is still there (channel busy ;)
case RELEASE:
level -= 1/200;
if(level <= 0) {
currentphase = NOOUT;
level = 0;
}
break;
case NOOUT:
artsdebug("ADSR: entering attack\n");
increment = 1 / (attack[i] * samplingRateFloat);
currentphase = ATTACK;
break;
case ATTACK:
level += increment;
if (level >= 1)
{
level = 1;
currentphase = DECAY;
decrement = (1-sustain[i]) /
(decay[i] * samplingRateFloat);
}
break;
case DECAY:
level -= decrement;
if (level <= sustain[i])
{
level = sustain[i];
currentphase = SUSTAIN;
}
break;
case SUSTAIN:
level = sustain[i];
break;
}
}
outvalue[i] = invalue[i] * level;
}
}
REGISTER_IMPLEMENTATION(Synth_ENVELOPE_ADSR_impl);
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