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/* ScummVM - Scumm Interpreter
* Copyright (C) 2007 The ScummVM project
*
* 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.
*
* $URL$
* $Id$
*
*/
#include "sound/mods/paula.h"
namespace Audio {
Paula::Paula(bool stereo, int rate, int interruptFreq) :
_stereo(stereo), _rate(rate), _intFreq(interruptFreq) {
_playing = false;
clearVoices();
_voice[0].panning = 63;
_voice[1].panning = 191;
_voice[2].panning = 191;
_voice[3].panning = 63;
if (_intFreq <= 0)
_intFreq = _rate;
_curInt = _intFreq;
_end = true;
}
Paula::~Paula() {
}
void Paula::clearVoice(byte voice) {
assert(voice < NUM_VOICES);
_voice[voice].data = 0;
_voice[voice].dataRepeat = 0;
_voice[voice].length = 0;
_voice[voice].lengthRepeat = 0;
_voice[voice].period = 0;
_voice[voice].volume = 0;
_voice[voice].offset = 0;
}
int Paula::readBuffer(int16 *buffer, const int numSamples) {
int voice;
int samples;
int nSamples;
int sLen;
double frequency;
double rate;
double offset;
int16 *p;
const int8 *data;
Common::StackLock lock(_mutex);
memset(buffer, 0, numSamples * 2);
if (!_playing) {
return numSamples;
}
samples = _stereo ? numSamples / 2 : numSamples;
while (samples > 0) {
if (_curInt == _intFreq) {
interrupt();
_curInt = 0;
}
nSamples = MIN(samples, _intFreq - _curInt);
for (voice = 0; voice < NUM_VOICES; voice++) {
if (!_voice[voice].data || (_voice[voice].period <= 0))
continue;
frequency = (7093789.2 / 2.0) / _voice[voice].period;
rate = frequency / _rate;
offset = _voice[voice].offset;
sLen = _voice[voice].length;
data = _voice[voice].data;
p = buffer;
_voice[voice].volume = MIN((byte) 0x40, _voice[voice].volume);
if ((_voice[voice].lengthRepeat > 2) &&
((int)(offset + nSamples * rate) >= sLen)) {
int neededSamples = nSamples;
int end = (int)((sLen - offset) / rate);
for (int i = 0; i < end; i++)
mix(p, data[(int)(offset + rate * i)], voice);
_voice[voice].length = sLen = _voice[voice].lengthRepeat;
_voice[voice].data = data = _voice[voice].dataRepeat;
_voice[voice].offset = offset = 0;
neededSamples -= end;
while (neededSamples > 0) {
if (neededSamples >= (int) ((sLen - offset) / rate)) {
while (rate > (sLen - offset))
rate -= (sLen - offset);
end = (int)((sLen - offset) / rate);
for (int i = 0; i < end; i++)
mix(p, data[(int)(offset + rate * i)], voice);
_voice[voice].data = data = _voice[voice].dataRepeat;
_voice[voice].length = sLen =
_voice[voice].lengthRepeat;
_voice[voice].offset = offset = 0;
neededSamples -= end;
} else {
for (int i = 0; i < neededSamples; i++)
mix(p, data[(int)(offset + rate * i)], voice);
_voice[voice].offset += rate * neededSamples;
if (ceil(_voice[voice].offset) >= sLen) {
_voice[voice].data = data = _voice[voice].dataRepeat;
_voice[voice].length = sLen =
_voice[voice].lengthRepeat;
_voice[voice].offset = offset = 0;
}
neededSamples = 0;
}
}
} else {
if (offset < sLen) {
if ((int)(offset + nSamples * rate) >= sLen) {
// The end of the sample is the limiting factor
int end = (int)((sLen - offset) / rate);
for (int i = 0; i < end; i++)
mix(p, data[(int)(offset + rate * i)], voice);
_voice[voice].offset = sLen;
} else {
// The requested number of samples is the limiting
// factor, not the sample
for (int i = 0; i < nSamples; i++)
mix(p, data[(int)(offset + rate * i)], voice);
_voice[voice].offset += rate * nSamples;
}
}
}
}
buffer += _stereo ? nSamples * 2 : nSamples;
_curInt += nSamples;
samples -= nSamples;
}
return numSamples;
}
} // End of namespace Audio
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