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-rw-r--r-- | engines/sword1/vag.cpp | 114 | ||||
-rw-r--r-- | engines/sword1/vag.h | 58 |
2 files changed, 172 insertions, 0 deletions
diff --git a/engines/sword1/vag.cpp b/engines/sword1/vag.cpp new file mode 100644 index 0000000000..afd064ad4a --- /dev/null +++ b/engines/sword1/vag.cpp @@ -0,0 +1,114 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * 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 "sword1/vag.h" + +namespace Sword1 { + +VagStream::VagStream(Common::SeekableReadStream *stream, bool loop) : _stream(stream) { + _samplesRemaining = 0; + _predictor = 0; + _s1 = _s2 = 0.0; + _loop = loop; +} + + +VagStream::~VagStream() { +} + +double f[5][2] = { { 0.0, 0.0 }, + { 60.0 / 64.0, 0.0 }, + { 115.0 / 64.0, -52.0 / 64.0 }, + { 98.0 / 64.0, -55.0 / 64.0 }, + { 122.0 / 64.0, -60.0 / 64.0 } }; + +int VagStream::readBuffer(int16 *buffer, const int numSamples) { + int32 samplesDecoded = 0; + + if (_samplesRemaining) { + byte i = 0; + + for (i = 28 - _samplesRemaining; i < 28 && samplesDecoded < numSamples; i++) { + _samples[i] = _samples[i] + _s1 * f[_predictor][0] + _s2 * f[_predictor][1]; + _s2 = _s1; + _s1 = _samples[i]; + int16 d = (int) (_samples[i] + 0.5); + buffer[samplesDecoded] = d; + samplesDecoded++; + } + + assert(i == 28); // We're screwed if this fails :P + _samplesRemaining = 0; + } + + while (samplesDecoded < numSamples) { + byte i = 0; + + _predictor = _stream->readByte(); + byte shift = _predictor & 0xf; + _predictor >>= 4; + + if (_stream->readByte() == 7) + return samplesDecoded; + + for (i = 0; i < 28; i += 2) { + byte d = _stream->readByte(); + int16 s = (d & 0xf) << 12; + if (s & 0x8000) + s |= 0xffff0000; + _samples[i] = (double)(s >> shift); + s = (d & 0xf0) << 8; + if (s & 0x8000) + s |= 0xffff0000; + _samples[i + 1] = (double)(s >> shift); + } + + for (i = 0; i < 28 && samplesDecoded < numSamples; i++) { + _samples[i] = _samples[i] + _s1 * f[_predictor][0] + _s2 * f[_predictor][1]; + _s2 = _s1; + _s1 = _samples[i]; + int16 d = (int) (_samples[i] + 0.5); + buffer[samplesDecoded] = d; + samplesDecoded++; + } + + if (i != 27) + _samplesRemaining = 28 - i; + } + + if(_loop && _stream->eos()) + rewind(); + + return samplesDecoded; +} + +void VagStream::rewind() { + _stream->seek(0); + _samplesRemaining = 0; + _predictor = 0; + _s1 = _s2 = 0.0; +} + +} diff --git a/engines/sword1/vag.h b/engines/sword1/vag.h new file mode 100644 index 0000000000..e9f429a599 --- /dev/null +++ b/engines/sword1/vag.h @@ -0,0 +1,58 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * 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. + * + * $URL$ + * $Id$ + * + */ + +#ifndef SWORD1_VAG_H +#define SWORD1_VAG_H + +#include "sound/audiostream.h" +#include "common/stream.h" + +namespace Sword1 { + +class VagStream : public Audio::AudioStream { +public: + VagStream(Common::SeekableReadStream *stream, bool loop = false); + ~VagStream(); + + bool isStereo() const { return false; } + bool endOfData() const { return _stream->pos() == _stream->size(); } + int getRate() const { return 11025; } + int readBuffer(int16 *buffer, const int numSamples); + + void rewind(); + +private: + Common::SeekableReadStream *_stream; + + bool _loop; + byte _predictor; + double _samples[28]; + byte _samplesRemaining; + double _s1, _s2; +}; + +} // End of namespace Sword1 + +#endif |