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122 lines
2.8 KiB
122 lines
2.8 KiB
15 years ago
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/*
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Copyright (C) 2000 Stefan Westerfeld
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stefan@space.twc.de
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public License
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along with this library; see the file COPYING.LIB. If not, write to
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15 years ago
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA.
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15 years ago
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*/
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#include "artsmodulessynth.h"
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#include "debug.h"
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#include "stdsynthmodule.h"
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using namespace Arts;
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class Synth_ENVELOPE_ADSR_impl : virtual public Synth_ENVELOPE_ADSR_skel,
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virtual public StdSynthModule
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{
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protected:
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enum { NOOUT, ATTACK, SUSTAIN, DECAY, RELEASE } currentphase;
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float level,increment,decrement;
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public:
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void streamInit()
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{
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currentphase = NOOUT;
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level = 0;
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}
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void calculateBlock(unsigned long samples);
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};
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void Synth_ENVELOPE_ADSR_impl::calculateBlock(unsigned long samples)
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{
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/* FIXME:
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* should be rewritten as generic envelope, would certainly
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* be faster & more flexible
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*/
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unsigned long i;
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for(i=0;i<samples;i++)
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{
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done[i] = 0;
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if(active[i] < 0.5)
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{
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if(currentphase == NOOUT)
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{
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level = 0;
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done[i] = 1;
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}
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else
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{
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if(currentphase != RELEASE) {
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artsdebug("ADSR: entering release phase\n");
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currentphase = RELEASE;
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decrement = level / (release[i] * samplingRateFloat);
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}
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level -= decrement;
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if(level <= 0)
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{
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level = 0;
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currentphase = NOOUT;
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}
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}
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}
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else
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{
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switch(currentphase)
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{
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//quickly kill the note that is still there (channel busy ;)
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case RELEASE:
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level -= 1/200;
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if(level <= 0) {
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currentphase = NOOUT;
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level = 0;
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}
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break;
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case NOOUT:
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artsdebug("ADSR: entering attack\n");
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increment = 1 / (attack[i] * samplingRateFloat);
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currentphase = ATTACK;
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break;
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case ATTACK:
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level += increment;
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if (level >= 1)
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{
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level = 1;
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currentphase = DECAY;
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decrement = (1-sustain[i]) /
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(decay[i] * samplingRateFloat);
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}
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break;
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case DECAY:
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level -= decrement;
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if (level <= sustain[i])
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{
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level = sustain[i];
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currentphase = SUSTAIN;
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}
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break;
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case SUSTAIN:
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level = sustain[i];
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break;
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}
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}
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outvalue[i] = invalue[i] * level;
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}
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}
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REGISTER_IMPLEMENTATION(Synth_ENVELOPE_ADSR_impl);
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