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player_v2.h

/* ScummVM - Scumm Interpreter
 * Copyright (C) 2001  Ludvig Strigeus
 * Copyright (C) 2001-2005 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $Header: /cvsroot/scummvm/scummvm/scumm/player_v2.h,v 2.36.2.1 2005/10/18 02:11:21 sev Exp $
 *
 */

#ifndef PLAYER_V2_H
#define PLAYER_V2_H

#include "common/scummsys.h"
#include "common/mutex.h"
#include "scumm/music.h"
#include "sound/audiostream.h"

namespace Audio {
      class Mixer;
}

namespace Scumm {

class ScummEngine;

#if !defined(__GNUC__)
      #pragma START_PACK_STRUCTS
#endif

struct channel_data {
      uint16 time_left;          // 00
      uint16 next_cmd;           // 02
      uint16 base_freq;          // 04
      uint16 freq_delta;         // 06
      uint16 freq;               // 08
      uint16 volume;             // 10
      uint16 volume_delta;       // 12
      uint16 tempo;              // 14
      uint16 inter_note_pause;   // 16
      uint16 transpose;          // 18
      uint16 note_length;        // 20
      uint16 hull_curve;         // 22
      uint16 hull_offset;        // 24
      uint16 hull_counter;       // 26
      uint16 freqmod_table;      // 28
      uint16 freqmod_offset;     // 30
      uint16 freqmod_incr;       // 32
      uint16 freqmod_multiplier; // 34
      uint16 freqmod_modulo;     // 36
      uint16 unknown[4];         // 38 - 44
      uint16 music_timer;        // 46
      uint16 music_script_nr;    // 48
} GCC_PACK;

#if !defined(__GNUC__)
      #pragma END_PACK_STRUCTS
#endif


/**
 * Scumm V2 PC-Speaker MIDI driver.
 * This simulates the pc speaker sound, which is driven  by the 8253 (square
 * wave generator) and a low-band filter.
 */
00078 class Player_V2 : public AudioStream, public MusicEngine {
public:
      Player_V2(ScummEngine *scumm, bool pcjr);
      virtual ~Player_V2();

      virtual void setMusicVolume(int vol);
      virtual void startSound(int sound);
      virtual void stopSound(int sound);
      virtual void stopAllSounds();
      virtual int  getMusicTimer() const;
      virtual int  getSoundStatus(int sound) const;

      // AudioStream API
00091       int readBuffer(int16 *buffer, const int numSamples) {
            do_mix(buffer, numSamples / 2);
            return numSamples;
      }
00095       bool isStereo() const { return true; }
00096       bool endOfData() const { return false; }
00097       int getRate() const { return _sample_rate; }

protected:
      bool _isV3Game;
      Audio::Mixer *_mixer;
      ScummEngine *_vm;

      bool _pcjr;
      int _header_len;

      uint32 _sample_rate;
      uint32 _next_tick;
      uint32 _tick_len;
      unsigned int _update_step;
      unsigned int _decay;
      int _level;
      unsigned int _RNG;
      unsigned int _volumetable[16];

      int _timer_count[4];
      int _timer_output;

      int   _current_nr;
      byte *_current_data;
      int   _next_nr;
      byte *_next_data;
      byte *_retaddr;

private:
      union ChannelInfo {
            channel_data d;
            uint16 array[sizeof(channel_data)/2];
      };

      int _music_timer;
      int _music_timer_ctr;
      int _ticks_per_music_timer;

      const uint16 *_freqs_table;

      Common::Mutex _mutex;
      ChannelInfo _channels[5];

protected:
      void mutex_up();
      void mutex_down();

      virtual void nextTick();
      virtual void clear_channel(int i);
      virtual void chainSound(int nr, byte *data);
      virtual void chainNextSound();

      virtual void generateSpkSamples(int16 *data, uint len);
      virtual void generatePCjrSamples(int16 *data, uint len);

      void lowPassFilter(int16 *data, uint len);
      void squareGenerator(int channel, int freq, int vol,
                                    int noiseFeedback, int16 *sample, uint len);

private:
      void do_mix(int16 *buf, uint len);

      void set_pcjr(bool pcjr);
      void execute_cmd(ChannelInfo *channel);
      void next_freqs(ChannelInfo *channel);
};

} // End of namespace Scumm

#endif

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