mididrv_m_adlib.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 NUVIE_SOUND_MIDIDRV_M_ADLIB_H
#define NUVIE_SOUND_MIDIDRV_M_ADLIB_H

#include "audio/adlib_ms.h"

namespace Ultima {
namespace Nuvie {

class MidiDriver_M_AdLib : public MidiDriver_ADLIB_Multisource {
protected:
    // The direction of a volume fade: in (increase) or out (decrease).
    enum FadeDirection {
        FADE_DIRECTION_NONE,
        FADE_DIRECTION_FADE_IN,
        FADE_DIRECTION_FADE_OUT
    };

    // The current direction of vibrato pitch change.
    enum VibratoDirection {
        VIBRATO_DIRECTION_RISING,
        VIBRATO_DIRECTION_FALLING
    };

    // Converts M note values to OPL frequency (F-num) values.
    static const uint16 FNUM_VALUES[24];

public:
    MidiDriver_M_AdLib();
    ~MidiDriver_M_AdLib();

    using MidiDriver_Multisource::send;
    void send(int8 source, uint32 b) override;
    void metaEvent(int8 source, byte type, byte *data, uint16 length) override;

protected:
    void programChange(uint8 channel, uint8 program, uint8 source) override;
    void modulation(uint8 channel, uint8 modulation, uint8 source) override;

    uint8 allocateOplChannel(uint8 channel, uint8 source, uint8 instrumentId) override;
    uint16 calculateFrequency(uint8 channel, uint8 source, uint8 note) override;
    uint8 calculateUnscaledVolume(uint8 channel, uint8 source, uint8 velocity, OplInstrumentDefinition &instrumentDef, uint8 operatorNum) override;
    void writeVolume(uint8 oplChannel, uint8 operatorNum, OplInstrumentRhythmType rhythmType = RHYTHM_TYPE_UNDEFINED) override;

    void deinitSource(uint8 source) override;

    void onTimer() override;

    // Number of F-num units each channel will increase/decrease each tick.
    int8 _slideValues[9];
    // Maximum number of F-num units the frequency will be changed by vibrato,
    // before applying the factor, for each channel. This is the difference
    // between the lowest and highest value (so twice the amplitude).
    uint8 _vibratoDepths[9];
    // Multiplication factor for vibrato F-num values for each channel.
    uint8 _vibratoFactors[9];
    // The current "progression" of vibrato through the cycle for each channel.
    // This is before the vibrato factor is applied.
    uint8 _vibratoCurrentDepths[9];
    // The current direction in which the vibrato is progressing for each
    // channel (rising or falling frequency).
    VibratoDirection _vibratoDirections[9];
    // The direction of the fade currently active on each channel (in or out).
    // NONE indicates no fade is active.
    FadeDirection _fadeDirections[9];
    // The delay in ticks between each level increase or decrease for each
    // channel.
    uint8 _fadeStepDelays[9];
    // The current fade delay counter value for each channel.
    uint8 _fadeCurrentDelays[9];
};

} // End of namespace Nuvie
} // End of namespace Ultima

#endif