SCUMM: Implement original AD AdLib output.

This implements the original AD output and enables it for Indy3 and Loom DOS.
It is not enabled for Monkey Island DOS because it would break multi MIDI
support. However, there are also drawbacks for Indy3. In the catacombs
we were able to play sfx (Indy walking around) and the background music
at once. This was not supported in the original player and thus also does
not work with this reimplementation.

This fixes bug #2027877 "INDY3: Non-Looping Sound Effects".
This fixes bug #1159581 "ADLIB: Adlib Emulation doesn't Respect Volume Settings"
for Indy3 and Loom.

1 files changed, 190 insertions, 0 deletions

diff --git a/engines/scumm/player_ad.h b/engines/scumm/player_ad.h
new file mode 100644
index 0000000000..da6c7177ef
--- /dev/null
+++ b/engines/scumm/player_ad.h
@@ -0,0 +1,190 @@
+/* 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.
+ *
+ */
+
+#ifndef SCUMM_PLAYER_AD_H
+#define SCUMM_PLAYER_AD_H
+
+#include "scumm/music.h"
+
+#include "audio/audiostream.h"
+#include "audio/mixer.h"
+
+#include "common/mutex.h"
+
+namespace OPL {
+class OPL;
+}
+
+namespace Scumm {
+
+class ScummEngine;
+
+/**
+ * Sound output for v3/v4 AdLib data.
+ */
+class Player_AD : public MusicEngine, public Audio::AudioStream {
+public:
+	Player_AD(ScummEngine *scumm, Audio::Mixer *mixer);
+	virtual ~Player_AD();
+
+	// MusicEngine API
+	virtual void setMusicVolume(int vol);
+	virtual void startSound(int sound);
+	virtual void stopSound(int sound);
+	virtual void stopAllSounds();
+	virtual int  getMusicTimer();
+	virtual int  getSoundStatus(int sound) const;
+
+	virtual void saveLoadWithSerializer(Serializer *ser);
+
+	// AudioStream API
+	virtual int readBuffer(int16 *buffer, const int numSamples);
+	virtual bool isStereo() const { return false; }
+	virtual bool endOfData() const { return false; }
+	virtual int getRate() const { return _rate; }
+
+private:
+	ScummEngine *const _vm;
+	Common::Mutex _mutex;
+	Audio::Mixer *const _mixer;
+	const int _rate;
+	Audio::SoundHandle _soundHandle;
+	void setupVolume();
+
+	OPL::OPL *_opl2;
+
+	int _samplesPerCallback;
+	int _samplesPerCallbackRemainder;
+	int _samplesTillCallback;
+	int _samplesTillCallbackRemainder;
+
+	int _soundPlaying;
+	int _engineMusicTimer;
+
+	// AdLib register utilities
+	uint8 _registerBackUpTable[256];
+	void writeReg(int r, int v);
+	uint8 readReg(int r) const;
+
+	// Instrument setup
+	void setupChannel(const uint channel, uint instrOffset) {
+		setupChannel(channel, _resource + instrOffset);
+	}
+	void setupChannel(const uint channel, const byte *instrOffset);
+	void setupOperator(const uint opr, const byte *&instrOffset);
+	static const int _operatorOffsetTable[18];
+
+	// Sound data
+	const byte *_resource;
+
+	// Music handling
+	void startMusic();
+	void updateMusic();
+	void noteOff(uint channel);
+	int findFreeChannel();
+	void setupFrequency(uint channel, int8 frequency);
+	void setupRhythm(uint rhythmInstr, uint instrOffset);
+
+	uint _timerLimit;
+	uint _musicTicks;
+	uint _musicTimer;
+	uint _internalMusicTimer;
+	bool _loopFlag;
+	uint _musicLoopStart;
+	uint _instrumentOffset[16];
+	uint _channelLastEvent[9];
+	uint _channelFrequency[9];
+	uint _channelB0Reg[9];
+
+	uint _mdvdrState;
+	uint _voiceChannels;
+	
+	uint _curOffset;
+	uint _nextEventTimer;
+
+	static const uint _noteFrequencies[12];
+	static const uint _mdvdrTable[6];
+	static const uint _rhythmOperatorTable[6];
+	static const uint _rhythmChannelTable[6];
+
+	// SFX handling
+	void startSfx();
+	void updateSfx();
+	void clearChannel(int channel);
+	void updateChannel(int channel);
+	void parseSlot(int channel);
+	void updateSlot(int channel);
+	void parseNote(int channel, int num, const byte *offset);
+	bool processNote(int note, const byte *offset);
+	void noteOffOn(int channel);
+	void writeRegisterSpecial(int note, uint8 value, int offset);
+	uint8 readRegisterSpecial(int note, uint8 defaultValue, int offset);
+	void setupNoteEnvelopeState(int note, int steps, int adjust);
+	bool processNoteEnvelope(int note, int &instrumentValue);
+
+	int _sfxTimer;
+
+	int _sfxResource[3];
+	int _sfxPriority[3];
+
+	struct Channel {
+		int state;
+		const byte *currentOffset;
+		const byte *startOffset;
+		uint8 instrumentData[7];
+	} _channels[11];
+
+	uint8 _rndSeed;
+	uint8 getRnd();
+
+	struct Note {
+		int state;
+		int playTime;
+		int sustainTimer;
+		int instrumentValue;
+		int bias;
+		int preIncrease;
+		int adjust;
+		
+		struct Envelope {
+			int stepIncrease;
+			int step;
+			int stepCounter;
+			int timer;
+		} envelope;
+	} _notes[22];
+
+	static const uint _noteBiasTable[7];
+	static const uint _numStepsTable[16];
+	static const uint _noteAdjustScaleTable[7];
+	static const uint _noteAdjustTable[16];
+	static const bool _useOperatorTable[7];
+	static const uint _channelOffsetTable[11];
+	static const uint _channelOperatorOffsetTable[7];
+	static const uint _baseRegisterTable[7];
+	static const uint _registerMaskTable[7];
+	static const uint _registerShiftTable[7];
+};
+
+} // End of namespace Scumm
+
+#endif