Logo Search packages:      
Sourcecode: scummvm version File versions  Download package

paula.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 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.
 *
 * $URL$
 * $Id$
 *
 */

#ifndef SOUND_MODS_PAULA_H
#define SOUND_MODS_PAULA_H

#include "audio/audiostream.h"
#include "common/frac.h"
#include "common/mutex.h"

namespace Audio {

/**
 * Emulation of the "Paula" Amiga music chip
 * The interrupt frequency specifies the number of mixed wavesamples between
 * calls of the interrupt method
 */
00040 class Paula : public AudioStream {
public:
      static const int NUM_VOICES = 4;
      enum {
            kPalSystemClock  = 7093790,
            kNtscSystemClock = 7159090,
            kPalCiaClock     = kPalSystemClock / 10,
            kNtscCiaClock    = kNtscSystemClock / 10,
            kPalPaulaClock   = kPalSystemClock / 2,
            kNtscPauleClock  = kNtscSystemClock / 2
      };

      /* TODO: Document this */
00053       struct Offset {
            uint  int_off;    // integral part of the offset
            frac_t      rem_off;    // fractional part of the offset, at least 0 and less than 1

            explicit Offset(int off = 0) : int_off(off), rem_off(0) {}
      };

      Paula(bool stereo = false, int rate = 44100, uint interruptFreq = 0);
      ~Paula();

      bool playing() const { return _playing; }
      void setTimerBaseValue( uint32 ticksPerSecond ) { _timerBase = ticksPerSecond; }
      uint32 getTimerBaseValue() { return _timerBase; }
      void setSingleInterrupt(uint sampleDelay) { assert(sampleDelay < _intFreq); _curInt = sampleDelay; }
      void setSingleInterruptUnscaled(uint timerDelay) {
            setSingleInterrupt((uint)(((double)timerDelay * getRate()) / _timerBase));
      }
      void setInterruptFreq(uint sampleDelay) { _intFreq = sampleDelay; _curInt = 0; }
      void setInterruptFreqUnscaled(uint timerDelay) {
            setInterruptFreq((uint)(((double)timerDelay * getRate()) / _timerBase));
      }
      void clearVoice(byte voice);
      void clearVoices() { for (int i = 0; i < NUM_VOICES; ++i) clearVoice(i); }
      void startPlay() { _playing = true; }
      void stopPlay() { _playing = false; }
      void pausePlay(bool pause) { _playing = !pause; }

// AudioStream API
      int readBuffer(int16 *buffer, const int numSamples);
00082       bool isStereo() const { return _stereo; }
00083       bool endOfData() const { return _end; }
00084       int getRate() const { return _rate; }

protected:
00087       struct Channel {
            const int8 *data;
            const int8 *dataRepeat;
            uint32 length;
            uint32 lengthRepeat;
            int16 period;
            byte volume;
            Offset offset;
            byte panning; // For stereo mixing: 0 = far left, 255 = far right
            int dmaCount;
      };

      bool _end;
      Common::Mutex _mutex;

      virtual void interrupt() = 0;

      void startPaula() {
            _playing = true;
            _end = false;
      }

      void stopPaula() {
            _playing = false;
            _end = true;
      }

      void setChannelPanning(byte channel, byte panning) {
            assert(channel < NUM_VOICES);
            _voice[channel].panning = panning;
      }

      void disableChannel(byte channel) {
            assert(channel < NUM_VOICES);
            _voice[channel].data = 0;
      }

      void enableChannel(byte channel) {
            assert(channel < NUM_VOICES);
            Channel &ch = _voice[channel];
            ch.data = ch.dataRepeat;
            ch.length = ch.lengthRepeat;
            // actually first 2 bytes are dropped?
            ch.offset = Offset(0);
            // ch.period = ch.periodRepeat;
      }

      void setChannelPeriod(byte channel, int16 period) {
            assert(channel < NUM_VOICES);
            _voice[channel].period = period;
      }

      void setChannelVolume(byte channel, byte volume) {
            assert(channel < NUM_VOICES);
            _voice[channel].volume = volume;
      }

      void setChannelSampleStart(byte channel, const int8 *data) {
            assert(channel < NUM_VOICES);
            _voice[channel].dataRepeat = data;
      }

      void setChannelSampleLen(byte channel, uint32 length) {
            assert(channel < NUM_VOICES);
            assert(length < 32768/2);
            _voice[channel].lengthRepeat = 2 * length;
      }

      void setChannelData(uint8 channel, const int8 *data, const int8 *dataRepeat, uint32 length, uint32 lengthRepeat, int32 offset = 0) {
            assert(channel < NUM_VOICES);

            Channel &ch = _voice[channel];

            ch.dataRepeat = data;
            ch.lengthRepeat = length;
            enableChannel(channel);
            ch.offset = Offset(offset);

            ch.dataRepeat = dataRepeat;
            ch.lengthRepeat = lengthRepeat;
      }

      void setChannelOffset(byte channel, Offset offset) {
            assert(channel < NUM_VOICES);
            _voice[channel].offset = offset;
      }

      Offset getChannelOffset(byte channel) {
            assert(channel < NUM_VOICES);
            return _voice[channel].offset;
      }

      int getChannelDmaCount(byte channel) {
            assert(channel < NUM_VOICES);
            return _voice[channel].dmaCount;
      }

      void setChannelDmaCount(byte channel, int dmaVal = 0) {
            assert(channel < NUM_VOICES);
            _voice[channel].dmaCount = dmaVal;
      }

      void setAudioFilter(bool enable) {
            // TODO: implement
      }

private:
      Channel _voice[NUM_VOICES];

      const bool _stereo;
      const int _rate;
      const double _periodScale;
      uint _intFreq;
      uint _curInt;
      uint32 _timerBase;
      bool _playing;

      template<bool stereo>
      int readBufferIntern(int16 *buffer, const int numSamples);
};

} // End of namespace Audio

#endif

Generated by  Doxygen 1.6.0   Back to index