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Diffstat (limited to 'sound/mods/paula.cpp')
| -rw-r--r-- | sound/mods/paula.cpp | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/sound/mods/paula.cpp b/sound/mods/paula.cpp new file mode 100644 index 0000000000..90d247096c --- /dev/null +++ b/sound/mods/paula.cpp @@ -0,0 +1,167 @@ +/* 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) { + if (voice >= 4) + return; + + _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; + int8 *data; + + _mutex.lock(); + + memset(buffer, 0, numSamples * 2); + if (!_playing) + { + _mutex.unlock(); + 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 < 4; 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 &= 0x3F; + 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)) { + 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; + } + _mutex.unlock(); + return numSamples; +} + +} // End of namespace Audio |