aboutsummaryrefslogtreecommitdiff
path: root/engines/agi/sound_midi.cpp
blob: d2c99171e2940f4a5c2baa876f7f612fe410c6ed (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
/* 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.
 *
 */

// Code is based on:
//
// A very simple program, that converts an AGI-song into a MIDI-song.
// Feel free to use it for anything.
//
// The default instrument is "piano" for all the channels, what gives
// good results on most games. But I found, that some songs are interesting
// with other instruments. If you want to experiment, modify the "instr"
// array.
//
// Timing is not perfect, yet. It plays correct, when I use the
// Gravis-Midiplayer, but the songs are too fast when I use playmidi on
// Linux.
// 
// Original program developed by Jens. Christian Restemeier
//

// MIDI and digital music class

#include "audio/audiostream.h"
#include "audio/mididrv.h"
#include "audio/midiparser.h"
#include "common/config-manager.h"
#include "common/file.h"
#include "common/memstream.h"
#include "common/stream.h"
#include "common/textconsole.h"

#include "agi/agi.h"

#include "agi/sound.h"
#include "agi/sound_midi.h"

#define SPEED_FACTOR 6

namespace Agi {

static uint32 convertSND2MIDI(byte *snddata, byte **data);

MIDISound::MIDISound(uint8 *data, uint32 len, int resnum, SoundMgr &manager) : AgiSound(manager) {
	_data = data; // Save the resource pointer
	_len  = len;  // Save the resource's length
	_type = READ_LE_UINT16(data); // Read sound resource's type
	_isValid = (_type == AGI_SOUND_4CHN) && (_data != NULL) && (_len >= 2);

	if (!_isValid) // Check for errors
		warning("Error creating MIDI sound from resource %d (Type %d, length %d)", resnum, _type, len);
}

SoundGenMIDI::SoundGenMIDI(AgiEngine *vm, Audio::Mixer *pMixer) : SoundGen(vm, pMixer), _isGM(false) {
	MidiPlayer::createDriver(MDT_MIDI | MDT_ADLIB);

	int ret = _driver->open();
	if (ret == 0) {
		if (_nativeMT32)
			_driver->sendMT32Reset();
		else
			_driver->sendGMReset();

		// FIXME: We need to cast "this" here due to the effects of
		// multiple inheritance. This hack can go away once this
		// setTimerCallback() has been moved inside Audio::MidiPlayer code.
		_driver->setTimerCallback(static_cast<Audio::MidiPlayer *>(this), &timerCallback);
	}
}

void SoundGenMIDI::send(uint32 b) {
	if ((b & 0xF0) == 0xC0 && !_isGM && !_nativeMT32) {
		b = (b & 0xFFFF00FF) | MidiDriver::_mt32ToGm[(b >> 8) & 0xFF] << 8;
	}

	Audio::MidiPlayer::send(b);
}

void SoundGenMIDI::sendToChannel(byte channel, uint32 b) {
	if (!_channelsTable[channel]) {
		_channelsTable[channel] = (channel == 9) ? _driver->getPercussionChannel() : _driver->allocateChannel();
		// If a new channel is allocated during the playback, make sure
		// its volume is correctly initialized.
		if (_channelsTable[channel])
			_channelsTable[channel]->volume(_channelsVolume[channel] * _masterVolume / 255);
	}

	if (_channelsTable[channel])
		_channelsTable[channel]->send(b);
}

void SoundGenMIDI::endOfTrack() {
	stop();
	_vm->_sound->soundIsFinished();
}

void SoundGenMIDI::play(int resnum) {
	MIDISound *track;
 
	stop();

	_isGM = true;

	track = (MIDISound *)_vm->_game.sounds[resnum];

	// Convert AGI Sound data to MIDI
	int midiMusicSize = convertSND2MIDI(track->_data, &_midiData);

	MidiParser *parser = MidiParser::createParser_SMF();
	if (parser->loadMusic(_midiData, midiMusicSize)) {
		parser->setTrack(0);
		parser->setMidiDriver(this);
		parser->setTimerRate(_driver->getBaseTempo());
		parser->property(MidiParser::mpCenterPitchWheelOnUnload, 1);

		_parser = parser;

		syncVolume();

		_isPlaying = true;
	} else {
		delete parser;
	}
}

/* channel / intrument setup: */

/* most songs are good with this: */
unsigned char instr[] = {0, 0, 0};

/* cool for sq2:
unsigned char instr[] = {50, 51, 19};
*/

static void writeDelta(Common::MemoryWriteStreamDynamic *st, int32 delta) {
	int32 i;

	i = delta >> 21; if (i > 0) st->writeByte((i & 127) | 128); 
	i = delta >> 14; if (i > 0) st->writeByte((i & 127) | 128);
	i = delta >> 7;  if (i > 0) st->writeByte((i & 127) | 128);
	st->writeByte(delta & 127);
}

static uint32 convertSND2MIDI(byte *snddata, byte **data) {
	int32 lp, ep;
	int n;
	double ll;

	Common::MemoryWriteStreamDynamic st;

	ll = log10(pow(2.0, 1.0 / 12.0));

	/* Header */
	st.write("MThd", 4);
	st.writeUint32BE(6);
	st.writeUint16BE(1);    /* mode */
	st.writeUint16BE(3);    /* number of tracks */
	st.writeUint16BE(192);  /* ticks / quarter */

	for (n = 0; n < 3; n++) {
		uint16 start, end, pos;

		st.write("MTrk", 4);
		lp = st.pos();
		st.writeUint32BE(0);        /* chunklength */
		writeDelta(&st, 0);       /* set instrument */
		st.writeByte(0xc0 + n);
		st.writeByte(instr[n]);
		start = snddata[n * 2 + 0] | (snddata[n * 2 + 1] << 8);
		end = ((snddata[n * 2 + 2] | (snddata[n * 2 + 3] << 8))) - 5;

		for (pos = start; pos < end; pos += 5) {
			uint16 freq,  dur;
			dur = (snddata[pos + 0] | (snddata[pos + 1] << 8)) * SPEED_FACTOR;
			freq = ((snddata[pos + 2] & 0x3F)  <<  4)  +  (snddata[pos + 3] & 0x0F);
			if (snddata[pos + 2] > 0) {
				double fr;
				int note;
				/* I don't know,  what frequency equals midi note 0 ... */
				/* This moves the song 4 octaves down: */
				fr = (log10(111860.0 / (double)freq) / ll) - 48; 
				note = (int)floor(fr + 0.5);
				if (note < 0) note = 0;
				if (note > 127) note = 127;
				/* note on */
				writeDelta(&st, 0);
				st.writeByte(144 + n);
				st.writeByte(note);
				st.writeByte(100);
				/* note off */
				writeDelta(&st, dur);
				st.writeByte(128 + n);
				st.writeByte(note);
				st.writeByte(0);
			} else {
				/* note on */
				writeDelta(&st, 0);
				st.writeByte(144 + n);
				st.writeByte(0);
				st.writeByte(0);
				/* note off */
				writeDelta(&st, dur);
				st.writeByte(128 + n);
				st.writeByte(0);
				st.writeByte(0);
			}
		}       
		writeDelta(&st, 0);
		st.writeByte(0xff);
		st.writeByte(0x2f);
		st.writeByte(0x0);
		ep = st.pos();
		st.seek(lp, SEEK_SET);
		st.writeUint32BE((ep - lp) - 4);
		st.seek(ep, SEEK_SET);
	}

	*data = st.getData();

	return st.pos();
}

} // End of namespace Agi