Logo Search packages:      
Sourcecode: scummvm version File versions

gmchannel.cpp

/* ScummVM - Scumm Interpreter
 * Copyright (C) 2003-2004 The ScummVM project
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * $Header: /cvsroot/scummvm/scummvm/sky/music/gmchannel.cpp,v 1.19 2004/08/26 13:53:20 eriktorbjorn Exp $
 *
 */

#include "gmchannel.h"
#include "common/util.h"
#include "sound/mididrv.h"

namespace Sky {

GmChannel::GmChannel(uint8 *pMusicData, uint16 startOfData, MidiDriver *pMidiDrv, byte *pInstMap, uint8 *veloTab) {

      _musicData = pMusicData;
      _midiDrv = pMidiDrv;
      _channelData.midiChannelNumber = 0;
      _channelData.startOfData = startOfData;
      _channelData.eventDataPtr = startOfData;
      _channelData.channelActive = 1;
      _channelData.nextEventTime = getNextEventTime();
      _mt32_to_gm = pInstMap;
      _veloTab = veloTab;

      _musicVolume = 0x7F;
      _lastVolume = 0xFF;
}

bool GmChannel::isActive(void) {

      return _channelData.channelActive != 0;
}

void GmChannel::updateVolume(uint16 pVolume) {

      _musicVolume = pVolume;
      if (_musicVolume > 0)
            _musicVolume = (_musicVolume * 2) / 3 + 43;
      if (_lastVolume < 0xFF) {
            uint8 newVol = (_lastVolume * _musicVolume) >> 7;
            _midiDrv->send((0xB0 | _channelData.midiChannelNumber) | 0x700 | (newVol << 16));
      }
}

void GmChannel::stopNote(void) {

      // All Notes Off
      _midiDrv->send((0xB0 | _channelData.midiChannelNumber) | 0x7B00 | 0 | 0x79000000);
      // Reset the Pitch Wheel. See bug #1016556.
      _midiDrv->send((0xE0 | _channelData.midiChannelNumber) | 0x400000);
}

int32 GmChannel::getNextEventTime(void) {

      int32 retV = 0; 
      uint8 cnt, lVal = 0;
      for (cnt = 0; cnt < 4; cnt++) {
            lVal = _musicData[_channelData.eventDataPtr];
            _channelData.eventDataPtr++;
            retV = (retV << 7) | (lVal & 0x7F);
            if (!(lVal & 0x80)) break;
      }
      if (lVal & 0x80) { // should never happen
            return -1;
      } else return retV;

}

uint8 GmChannel::process(uint16 aktTime) {

      if (!_channelData.channelActive)
            return 0;
      
      uint8 returnVal = 0;

      _channelData.nextEventTime -= aktTime;
      uint8 opcode;

      while ((_channelData.nextEventTime < 0) && (_channelData.channelActive)) {
            opcode = _musicData[_channelData.eventDataPtr];
            _channelData.eventDataPtr++;
            if (opcode&0x80) {
                  if (opcode == 0xFF) {
                        // dummy opcode
                  } else if (opcode >= 0x90) {
                        switch (opcode&0xF) {
                        case 0: com90_caseNoteOff(); break;
                        case 1: com90_stopChannel(); break;
                        case 2: com90_setupInstrument(); break;
                        case 3: 
                              returnVal = com90_updateTempo();
                              break;
                        case 5: com90_getPitch(); break;
                        case 6: com90_getChannelVolume(); break;
                        case 8: com90_rewindMusic(); break;
                        case 9: com90_keyOff(); break;
                        case 11: com90_getChannelPanValue(); break;
                        case 12: com90_setStartOfData(); break;
                        case 13: com90_getChannelControl(); break;
                        case 4: //com90_dummy();
                        case 7: //com90_skipTremoVibro();
                        case 10: //com90_error();
                              error("Channel: dummy music routine 0x%02X was called",opcode);
                              _channelData.channelActive = 0;
                              break;
                        default:
                              // these opcodes aren't implemented in original music driver
                              error("Channel: Not existent routine 0x%02X was called",opcode);
                              _channelData.channelActive = 0;
                              break;
                        }
                  } else {
                        // new midi channel assignment
                        _channelData.midiChannelNumber = opcode&0xF;
                  }
            } else {
                  _channelData.note = opcode;
                  uint8 velocity = _veloTab[_musicData[_channelData.eventDataPtr]];
                  _channelData.eventDataPtr++;
                  _midiDrv->send((0x90 | _channelData.midiChannelNumber) | (opcode << 8) | (velocity << 16));
            }
            if (_channelData.channelActive)
                  _channelData.nextEventTime += getNextEventTime();
      }
      return returnVal;
}

//- command 90h routines

void GmChannel::com90_caseNoteOff(void) {

      _midiDrv->send((0x90 | _channelData.midiChannelNumber) | (_musicData[_channelData.eventDataPtr] << 8));
      _channelData.eventDataPtr++;
}

void GmChannel::com90_stopChannel(void) {

      stopNote();
      _channelData.channelActive = 0;
}

void GmChannel::com90_setupInstrument(void) {

      _midiDrv->send((0xC0 | _channelData.midiChannelNumber) | (_mt32_to_gm[_musicData[_channelData.eventDataPtr]] << 8));
      _channelData.eventDataPtr++;
}

uint8 GmChannel::com90_updateTempo(void) {

      uint8 retV = _musicData[_channelData.eventDataPtr];
      _channelData.eventDataPtr++;
      return retV;
}

void GmChannel::com90_getPitch(void) {

      _midiDrv->send((0xE0 | _channelData.midiChannelNumber) | 0 | (_musicData[_channelData.eventDataPtr] << 16));
      _channelData.eventDataPtr++;
}

void GmChannel::com90_getChannelVolume(void) {

      _lastVolume = _musicData[_channelData.eventDataPtr];
      uint8 newVol = (uint8)((_musicData[_channelData.eventDataPtr++] * _musicVolume) >> 7);
      _midiDrv->send((0xB0 | _channelData.midiChannelNumber) | 0x700 | (newVol << 16));
}

void GmChannel::com90_rewindMusic(void) {

      _channelData.eventDataPtr = _channelData.startOfData;
}

void GmChannel::com90_keyOff(void) {

      _midiDrv->send((0x90 | _channelData.midiChannelNumber) | (_channelData.note << 8) | 0);
}

void GmChannel::com90_setStartOfData(void) {

      _channelData.startOfData = _channelData.eventDataPtr;
}

void GmChannel::com90_getChannelPanValue(void) {

      _midiDrv->send((0xB0 | _channelData.midiChannelNumber) | 0x0A00 | (_musicData[_channelData.eventDataPtr] << 16));
      _channelData.eventDataPtr++;
}

void GmChannel::com90_getChannelControl(void) {

      uint8 conNum = _musicData[_channelData.eventDataPtr];
      uint8 conDat = _musicData[_channelData.eventDataPtr + 1];
      _channelData.eventDataPtr += 2;
      _midiDrv->send((0xB0 | _channelData.midiChannelNumber) | (conNum << 8) | (conDat << 16));
}

} // End of namespace Sky

Generated by  Doxygen 1.6.0   Back to index