opl.music.h

/* 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef FREESCAPE_CASTLE_OPL_MUSIC_H
#define FREESCAPE_CASTLE_OPL_MUSIC_H

#include "audio/fmopl.h"
#include "freescape/music.h"

namespace Freescape {

class CastleOPLMusicPlayer : public MusicPlayer {
public:
    CastleOPLMusicPlayer();
    ~CastleOPLMusicPlayer() override;

    void startMusic() override;
    void stopMusic() override;
    bool isPlaying() const override;

private:
    enum {
        kChannelCount = 3,
        kMaxNote = 94
    };

    struct ChannelState {
        const byte *orderList;
        uint16 orderPosition;
        byte patternIndex;
        uint16 patternDataOffset;
        uint16 patternOffset;
        uint16 delay;
        byte instrument;
        int8 transpose;
        byte currentNote;
        uint16 baseSIDFrequency;
        int16 sidFrequencyOffset;
        uint16 baseFrequencyFnum;
        byte baseFrequencyBlock;
        uint16 frequencyFnum;
        byte frequencyBlock;
        byte vibratoStep;
        bool vibratoReverse;
        bool keyOn;
        bool gateReleased;

        void reset(const byte *channelOrderList);
    };

    OPL::OPL *_opl;
    bool _musicActive;
    uint32 _tick;
    ChannelState _channels[kChannelCount];

    void onTimer();
    void setupSong();
    void silenceAll();
    void loadNextPattern(int channel);
    byte readPatternByte(int channel);
    void parseCommands(int channel);
    void setOPLInstrument(int channel, byte instrument);
    void noteOn(int channel, byte note);
    void noteOff(int channel);
    void gateOff(int channel);
    void applyFrameEffects(int channel);
    void setFrequency(int channel, uint16 fnum, byte block);
    void writeFrequency(int channel, uint16 fnum, byte block);
    void noteToFnumBlock(int note, uint16 &fnum, byte &block) const;
};

} // namespace Freescape

#endif