AGI: Implement FR #2813133.

FR #2813133: "AGI: Proper Tandy 3-Voice/IBM PCjr Sound Support".
Add proper Tandy music. Heavily based on NAGI source, thus attached
its X11 license.

To run it now use -e pcjr. Old one is still default for adlib but
most likely will be changed in the future.

Also lied ground for further separation of different sound generators.

svn-id: r49755

1 files changed, 112 insertions, 0 deletions

diff --git a/engines/agi/sound_pcjr.h b/engines/agi/sound_pcjr.h
new file mode 100755
index 0000000000..9ef9aa2385
--- /dev/null
+++ b/engines/agi/sound_pcjr.h
@@ -0,0 +1,112 @@
+/* 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 AGI_SOUND_PCJR_H
+#define AGI_SOUND_PCJR_H
+
+namespace Agi {
+
+#define CHAN_MAX 4
+
+#define SAMPLE_RATE 22050
+
+enum GenType {
+	kGenSilence,
+	kGenTone,
+	kGenPeriod,
+	kGenWhite
+};
+
+struct SndGenChan {
+	const byte *data;
+	uint16 duration;
+	uint16 avail;	// turned on (1)  but when the channel's data runs out, it's set to (0)
+	uint16 dissolveCount;
+	byte attenuation;
+	byte attenuationCopy;
+	
+	GenType genType;
+	
+	// for the sample mixer
+	int freqCount;
+};
+
+struct ToneChan {
+	int avail;
+
+	int noteCount; // length of tone.. duration
+
+	int freqCount;
+	int freqCountPrev;
+	int atten;  // volume
+
+	GenType genType;
+	int genTypePrev;
+
+	int count;
+	int scale;
+	int sign;
+	unsigned int noiseState;		/* noise generator      */
+	int feedback;						/* noise feedback mask */
+};
+
+struct Tone {
+	int freqCount;
+	int atten;
+	GenType type;
+};
+
+class SoundGenPCJr : public SoundGen {
+public:
+	SoundGenPCJr(AgiEngine *vm);
+	~SoundGenPCJr();
+
+	void play(int resnum, int flag);
+	void stop(void);
+
+	void premixerCall(int16 *stream, int len);
+
+private:
+	int getNextNote(int ch, Tone *tone);
+	int volumeCalc(SndGenChan *chan);
+
+	int chanGen(int chan, int16 *stream, int len);
+
+	int fillNoise(ToneChan *t, int16 *buf, int len);
+	int fillSquare(ToneChan *t, int16 *buf, int len);
+
+private:
+	AgiEngine *_vm;
+	SndGenChan _channel[CHAN_MAX];
+	ToneChan _tchannel[CHAN_MAX];
+	int16 *_chanData;
+	int _chanAllocated;
+
+	int _dissolveMethod;
+};
+
+} // End of namespace Agi
+
+#endif /* AGI_SOUND_PCJR_H */