c64.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_ECLIPSE_C64_MUSIC_H
#define FREESCAPE_ECLIPSE_C64_MUSIC_H

#include "audio/sid.h"
#include "common/array.h"
#include "freescape/music.h"

namespace Freescape {

class EclipseC64MusicPlayer : public MusicPlayer {
public:
    EclipseC64MusicPlayer(const Common::Array<byte> &musicData);
    ~EclipseC64MusicPlayer();

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

private:
    static const uint16 kLoadAddress = 0x0410;
    static const uint16 kOrderPointerTable = 0x1041;
    static const uint16 kInstrumentTable = 0x1047;
    static const uint16 kPatternPointerLowTable = 0x10A7;
    static const uint16 kPatternPointerHighTable = 0x10C6;
    static const uint16 kFrequencyHighTable = 0x0F5F;
    static const uint16 kFrequencyLowTable = 0x0FBE;
    static const uint16 kArpeggioIntervalTable = 0x148B;

    static const byte kChannelCount = 3;
    static const byte kInstrumentCount = 12;
    static const byte kPatternCount = 31;
    static const byte kMaxNote = 94;

    struct ChannelState {
        uint16 orderAddr;
        byte orderPos;

        uint16 patternAddr;
        byte patternOffset;

        byte instrumentOffset;
        byte currentNote;
        byte transpose;

        byte frequencyLow;
        byte frequencyHigh;
        byte pulseWidthLow;
        byte pulseWidthHigh;

        byte durationReload;
        byte durationCounter;

        byte effectMode;
        byte effectParam;
        byte arpeggioTarget;
        byte arpeggioParam;
        byte arpeggioSequencePos;
        byte arpeggioSequence[9];
        byte arpeggioSequenceLen;

        byte noteStepCommand;
        byte stepDownCounter;

        byte vibratoPhase;
        byte vibratoCounter;
        byte pulseWidthDirection;

        byte delayValue;
        byte delayCounter;

        byte waveform;
        byte instrumentFlags;
        bool gateOffDisabled;

        void reset();
    };

    SID::SID *_sid;
    Common::Array<byte> _musicData;
    byte _arpeggioIntervals[8];
    bool _musicActive;
    byte _speedDivider;
    byte _speedCounter;
    ChannelState _channels[kChannelCount];

    byte readByte(uint16 address) const;
    uint16 readWordLE(uint16 address) const;
    uint16 readPatternPointer(byte index) const;
    byte readInstrumentByte(byte instrumentOffset, byte field) const;
    byte readPatternByte(int channel);
    byte clampNote(byte note) const;

    void sidWrite(int reg, byte data);
    void onTimer();
    void silenceAll();
    void setupSong();
    void loadNextPattern(int channel);
    void buildEffectArpeggio(int channel);
    void loadCurrentFrequency(int channel);
    void finalizeChannel(int channel);
    void processChannel(int channel, bool newBeat);
    void parseCommands(int channel);
    void applyNote(int channel, byte note);
    void applyFrameEffects(int channel);
    bool applyInstrumentVibrato(int channel);
    void applyEffectArpeggio(int channel);
    void applyTimedSlide(int channel);
    void applyPulseWidthModulation(int channel);

    void initSID();
    void destroySID();
};

} // namespace Freescape

#endif