Patch #2638336: Broken Sword PSX Support Part 2 of 2

svn-id: r38957

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