1 files changed, 277 insertions, 0 deletions
diff --git a/engines/sci/sound/drivers/pcjr.cpp b/engines/sci/sound/drivers/pcjr.cpp
new file mode 100644
index 0000000000..eb264fb9dd
--- /dev/null
+++ b/engines/sci/sound/drivers/pcjr.cpp
@@ -0,0 +1,277 @@
+/* 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 "sci/sound/drivers/mididriver.h"
+
+namespace Sci {
+
+#define VOLUME_SHIFT 3
+
+#define BASE_NOTE 129	// A10
+#define BASE_OCTAVE 10	// A10, as I said
+
+const static int freq_table[12] = { // A4 is 440Hz, halftone map is x |-> ** 2^(x/12)
+	28160, // A10
+	29834,
+	31608,
+	33488,
+	35479,
+	37589,
+	39824,
+	42192,
+	44701,
+	47359,
+	50175,
+	53159
+};
+
+static inline int get_freq(int note) {
+	int halftone_delta = note - BASE_NOTE;
+	int oct_diff = ((halftone_delta + BASE_OCTAVE * 12) / 12) - BASE_OCTAVE;
+	int halftone_index = (halftone_delta + (12 * 100)) % 12 ;
+	int freq = (!note) ? 0 : freq_table[halftone_index] / (1 << (-oct_diff));
+
+	return freq;
+}
+
+class MidiDriver_PCJr : public MidiDriver_Emulated {
+public:
+	friend class MidiPlayer_PCJr;
+
+	enum {
+		kMaxChannels = 3
+	};
+
+	MidiDriver_PCJr(Audio::Mixer *mixer) : MidiDriver_Emulated(mixer) { }
+	~MidiDriver_PCJr() { }
+
+	// MidiDriver
+	int open() { return open(kMaxChannels); }
+	void close();
+	void send(uint32 b);
+	MidiChannel *allocateChannel() { return NULL; }
+	MidiChannel *getPercussionChannel() { return NULL; }
+
+	// AudioStream
+	bool isStereo() const { return false; }
+	int getRate() const { return _mixer->getOutputRate(); }
+
+	// MidiDriver_Emulated
+	void generateSamples(int16 *buf, int len);
+
+	int open(int channels);
+private:
+	int _channels_nr;
+	int _global_volume; // Base volume
+	int _volumes[kMaxChannels];
+	int _notes[kMaxChannels]; // Current halftone, or 0 if off
+	int _freq_count[kMaxChannels];
+	int _channel_assigner;
+	int _channels_assigned;
+	int _chan_nrs[kMaxChannels];
+};
+
+void MidiDriver_PCJr::send(uint32 b) {
+	byte command = b & 0xff;
+	byte op1 = (b >> 8) & 0xff;
+	byte op2 = (b >> 16) & 0xff;
+	int i;
+	int mapped_chan = -1;
+	int chan_nr = command & 0xf;
+
+	// First, test for channel having been assigned already
+	if (_channels_assigned & (1 << chan_nr)) {
+		// Already assigned this channel number:
+		for (i = 0; i < _channels_nr; i++)
+			if (_chan_nrs[i] == chan_nr) {
+				mapped_chan = i;
+				break;
+			}
+	} else if ((command & 0xe0) == 0x80) {
+		// Assign new channel round-robin
+
+		// Mark channel as unused:
+		if (_chan_nrs[_channel_assigner] >= 0)
+			_channels_assigned &= ~(1 << _chan_nrs[_channel_assigner]);
+
+		// Remember channel:
+		_chan_nrs[_channel_assigner] = chan_nr;
+		// Mark channel as used
+		_channels_assigned |= (1 << _chan_nrs[_channel_assigner]);
+
+		// Save channel for use later in this call:
+		mapped_chan = _channel_assigner;
+		// Round-ropin iterate channel assigner:
+		_channel_assigner = (_channel_assigner + 1) % _channels_nr;
+	}
+
+	if (mapped_chan == -1)
+		return;
+
+	switch (command & 0xf0) {
+
+	case 0x80:
+		if (op1 == _notes[mapped_chan])
+			_notes[mapped_chan] = 0;
+		break;
+
+	case 0x90:
+		if (!op2) {
+			if (op1 == _notes[mapped_chan])
+				_notes[mapped_chan] = 0;
+		} else {
+			_notes[mapped_chan] = op1;
+			_volumes[mapped_chan] = op2;
+		}
+		break;
+
+	case 0xb0:
+		if ((op1 == SCI_MIDI_CHANNEL_NOTES_OFF) || (op1 == SCI_MIDI_CHANNEL_SOUND_OFF))
+			_notes[mapped_chan] = 0;
+		break;
+
+	default:
+		debug(2, "Unused MIDI command %02x %02x %02x", command, op1, op2);
+		break; /* ignore */
+	}
+}
+
+void MidiDriver_PCJr::generateSamples(int16 *data, int len) {
+	int i;
+	int chan;
+	int freq[kMaxChannels];
+	int frequency = getRate();
+
+	for (chan = 0; chan < _channels_nr; chan++)
+		freq[chan] = get_freq(_notes[chan]);
+
+	for (i = 0; i < len; i++) {
+		int16 result = 0;
+
+		for (chan = 0; chan < _channels_nr; chan++)
+			if (_notes[chan]) {
+				int volume = (_global_volume * _volumes[chan])
+				             >> VOLUME_SHIFT;
+
+				_freq_count[chan] += freq[chan];
+				while (_freq_count[chan] >= (frequency << 1))
+					_freq_count[chan] -= (frequency << 1);
+
+				if (_freq_count[chan] - freq[chan] < 0) {
+					/* Unclean rising edge */
+					int l = volume << 1;
+					result += -volume + (l * _freq_count[chan]) / freq[chan];
+				} else if (_freq_count[chan] >= frequency
+				           && _freq_count[chan] - freq[chan] < frequency) {
+					/* Unclean falling edge */
+					int l = volume << 1;
+					result += volume - (l * (_freq_count[chan] - frequency)) / freq[chan];
+				} else {
+					if (_freq_count[chan] < frequency)
+						result += volume;
+					else
+						result += -volume;
+				}
+			}
+		data[i] = result;
+	}
+}
+
+int MidiDriver_PCJr::open(int channels) {
+	if (_isOpen)
+		return MERR_ALREADY_OPEN;
+
+	if (channels > kMaxChannels)
+		return -1;
+
+	_channels_nr = channels;
+	_global_volume = 100;
+	for (int i = 0; i < _channels_nr; i++) {
+		_volumes[i] = 100;
+		_notes[i] = 0;
+		_freq_count[i] = 0;
+		_chan_nrs[i] = -1;
+	}
+	_channel_assigner = 0;
+	_channels_assigned = 0;
+
+	MidiDriver_Emulated::open();
+
+	_mixer->playInputStream(Audio::Mixer::kPlainSoundType, &_mixerSoundHandle, this, -1, _mixer->kMaxChannelVolume, 0, DisposeAfterUse::NO);
+
+	return 0;
+}
+
+void MidiDriver_PCJr::close() {
+	_mixer->stopHandle(_mixerSoundHandle);
+}
+
+class MidiPlayer_PCJr : public MidiPlayer {
+public:
+	MidiPlayer_PCJr() { _driver = new MidiDriver_PCJr(g_system->getMixer()); }
+	int open(ResourceManager *resMan) { return static_cast<MidiDriver_PCJr *>(_driver)->open(getPolyphony()); }
+	byte getPlayId(SciVersion soundVersion);
+	int getPolyphony() const { return 3; }
+	bool hasRhythmChannel() const { return false; }
+	void setVolume(byte volume) { static_cast<MidiDriver_PCJr *>(_driver)->_global_volume = volume; }
+};
+
+byte MidiPlayer_PCJr::getPlayId(SciVersion soundVersion) {
+	switch (soundVersion) {
+	case SCI_VERSION_0_EARLY:
+		return 0x02;
+	case SCI_VERSION_0_LATE:
+		return 0x10;
+	default:
+		return 0x13;
+	}
+}
+
+MidiPlayer *MidiPlayer_PCJr_create() {
+	return new MidiPlayer_PCJr();
+}
+
+class MidiPlayer_PCSpeaker : public MidiPlayer_PCJr {
+public:
+	byte getPlayId(SciVersion soundVersion);
+	int getPolyphony() const { return 1; }
+};
+
+byte MidiPlayer_PCSpeaker::getPlayId(SciVersion soundVersion) {
+	switch (soundVersion) {
+	case SCI_VERSION_0_EARLY:
+		return 0x04;
+	case SCI_VERSION_0_LATE:
+		return 0x20;
+	default:
+		return 0x12;
+	}
+}
+
+MidiPlayer *MidiPlayer_PCSpeaker_create() {
+	return new MidiPlayer_PCSpeaker();
+}
+
+} // End of namespace Sci