sound_pcjr.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 AGI_SOUND_PCJR_H
#define AGI_SOUND_PCJR_H
 
#include "audio/audiostream.h"
 
namespace Agi {
 
#define CHAN_MAX 4
 
#define SAMPLE_RATE 22050
 
enum GenType {
    kGenSilence,
    kGenTone,
    kGenPeriod,
    kGenWhite
};
 
struct SndGenChan {
    const byte *data;
    uint16 duration;
    uint16 avail;   // turned on (1)  but when the channel's data runs out, it's set to (0)
    uint16 dissolveCount;
    byte attenuation;
    byte attenuationCopy;
 
    GenType genType;
 
    // for the sample mixer
    int freqCount;
};
 
struct ToneChan {
    int avail;
 
    int noteCount; // length of tone.. duration
 
    int freqCount;
    int freqCountPrev;
    int atten;  // volume
 
    GenType genType;
    int genTypePrev;
 
    int count;
    int scale;
    int sign;
    unsigned int noiseState; /* noise generator      */
    int feedback;            /* noise feedback mask */
};
 
class SoundGenPCJr : public SoundGen, public Audio::AudioStream {
public:
    SoundGenPCJr(AgiBase *vm, Audio::Mixer *pMixer);
    ~SoundGenPCJr() override;
 
    void play(int resnum) override;
    void stop() override;
 
    // AudioStream API
    int readBuffer(int16 *buffer, const int numSamples) override;
 
    bool isStereo() const override {
        return false;
    }
 
    bool endOfData() const override {
        return false;
    }
 
    int getRate() const override {
        // FIXME: Ideally, we should use _sampleRate.
        return 22050;
    }
 
private:
    int getNextNote(int ch);
    int getNextNote_v2(int ch);
    int getNextNote_v1(int ch);
    int volumeCalc(SndGenChan *chan);
 
    void writeData(uint8 val);
 
    int chanGen(int chan, int16 *stream, int len);
 
    int fillNoise(ToneChan *t, int16 *buf, int len);
    int fillSquare(ToneChan *t, int16 *buf, int len);
 
private:
    Common::Mutex _mutex;
    
    SndGenChan _channel[CHAN_MAX];
    ToneChan _tchannel[CHAN_MAX];
    int16 *_chanData;
    int _chanAllocated;
 
    int _dissolveMethod;
    int32 _periodicNoiseMask;
 
    uint8 *_v1data;
    uint32 _v1size;
    int _v1duration;
 
    int _reg;
};
 
} // End of namespace Agi
 
#endif /* AGI_SOUND_PCJR_H */