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sound_midi.cpp

/* 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: https://scummvm.svn.sourceforge.net/svnroot/scummvm/scummvm/tags/release-1-2-1/engines/agi/sound_midi.cpp $
 * $Id: sound_midi.cpp 52736 2010-09-15 22:00:20Z lordhoto $
 *
 */

// 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 "sound/audiostream.h"
#include "sound/mididrv.h"
#include "sound/midiparser.h"
#include "common/config-manager.h"
#include "common/file.h"
#include "common/stream.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), _parser(0), _isPlaying(false), _passThrough(false), _isGM(false) {
      DeviceHandle dev = MidiDriver::detectDevice(MDT_MIDI | MDT_ADLIB);
      _driver = MidiDriver::createMidi(dev);

      if (ConfMan.getBool("native_mt32") || MidiDriver::getMusicType(dev) == MT_MT32) {
            _nativeMT32 = true;
            _driver->property(MidiDriver::PROP_CHANNEL_MASK, 0x03FE);
      } else {
            _nativeMT32 = false;
      }

      memset(_channel, 0, sizeof(_channel));
      memset(_channelVolume, 255, sizeof(_channelVolume));
      _masterVolume = 0;
      this->open();
      _smfParser = MidiParser::createParser_SMF();
      _midiMusicData = NULL;
}

SoundGenMIDI::~SoundGenMIDI() {
      _driver->setTimerCallback(NULL, NULL);
      stop();
      this->close();
      _smfParser->setMidiDriver(NULL);
      delete _smfParser;
      delete[] _midiMusicData;
}

void SoundGenMIDI::setChannelVolume(int channel) {
      int newVolume = _channelVolume[channel] * _masterVolume / 255;
      _channel[channel]->volume(newVolume);
}

void SoundGenMIDI::setVolume(int volume) {
      Common::StackLock lock(_mutex);

      volume = CLIP(volume, 0, 255);
      if (_masterVolume == volume)
            return;
      _masterVolume = volume;

      for (int i = 0; i < 16; ++i) {
            if (_channel[i]) {
                  setChannelVolume(i);
            }
      }
}

00121 int SoundGenMIDI::open() {
      // Don't ever call open without first setting the output driver!
      if (!_driver)
            return 255;

      int ret = _driver->open();
      if (ret)
            return ret;

      _driver->setTimerCallback(this, &onTimer);

      if (_nativeMT32)
            _driver->sendMT32Reset();
      else
            _driver->sendGMReset();

      return 0;
}

00140 void SoundGenMIDI::close() {
      stop();
      if (_driver)
            _driver->close();
      _driver = 0;
}

00147 void SoundGenMIDI::send(uint32 b) {
      if (_passThrough) {
            _driver->send(b);
            return;
      }

      byte channel = (byte)(b & 0x0F);
      if ((b & 0xFFF0) == 0x07B0) {
            // Adjust volume changes by master volume
            byte volume = (byte)((b >> 16) & 0x7F);
            _channelVolume[channel] = volume;
            volume = volume * _masterVolume / 255;
            b = (b & 0xFF00FFFF) | (volume << 16);
      } else if ((b & 0xF0) == 0xC0 && !_isGM && !_nativeMT32) {
            b = (b & 0xFFFF00FF) | MidiDriver::_mt32ToGm[(b >> 8) & 0xFF] << 8;
      }
      else if ((b & 0xFFF0) == 0x007BB0) {
            //Only respond to All Notes Off if this channel
            //has currently been allocated
            if (_channel[b & 0x0F])
                  return;
      }

      if (!_channel[channel]) {
            _channel[channel] = (channel == 9) ? _driver->getPercussionChannel() : _driver->allocateChannel();
            // If a new channel is allocated during the playback, make sure
            // its volume is correctly initialized.
            if (_channel[channel])
                  setChannelVolume(channel);
      }

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

void SoundGenMIDI::metaEvent(byte type, byte *data, uint16 length) {

      switch (type) {
      case 0x2F:  // End of Track
            stop();
            _vm->_sound->soundIsFinished();
            break;
      default:
            //warning("Unhandled meta event: %02x", type);
            break;
      }
}

void SoundGenMIDI::onTimer(void *refCon) {
      SoundGenMIDI *music = (SoundGenMIDI *)refCon;
      Common::StackLock lock(music->_mutex);

      if (music->_parser)
            music->_parser->onTimer();
}

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, &_midiMusicData);

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

            _parser = parser;

            syncVolume();

            _isPlaying = true;
      }
}

void SoundGenMIDI::stop() {
      Common::StackLock lock(_mutex);

      if (!_isPlaying)
            return;

      _isPlaying = false;
      if (_parser) {
            _parser->unloadMusic();
            _parser = NULL;
      }
}

void SoundGenMIDI::pause() {
      setVolume(-1);
      _isPlaying = false;
}

void SoundGenMIDI::resume() {
      syncVolume();
      _isPlaying = true;
}

void SoundGenMIDI::syncVolume() {
      int volume = ConfMan.getInt("music_volume");
      if (ConfMan.getBool("mute")) {
            volume = -1;
      }
      setVolume(volume);
}

/* 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

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