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/* 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 AUDIO_SOFTSYNTH_PCSPK_H
#define AUDIO_SOFTSYNTH_PCSPK_H
#include "audio/audiostream.h"
#include "common/mutex.h"
#include "common/queue.h"
namespace Audio {
class PCSpeaker : public AudioStream {
public:
enum WaveForm {
kWaveFormSquare = 0,
kWaveFormSine,
kWaveFormSaw,
kWaveFormTriangle,
kWaveFormSilence
};
protected:
// PC speaker instruction: play this waveform at frequency x for y microseconds.
struct Command {
WaveForm waveForm;
float frequency;
uint32 length;
Command(WaveForm waveForm, float frequency, uint32 length);
};
public:
PCSpeaker(int rate = 44100);
~PCSpeaker();
/** Play a note for length ms.
*
* If length is negative, play until told to stop.
*/
void play(WaveForm wave, int freq, int32 length);
/**
* Queue the specified playback instruction. It will be executed when all
* previously queued instructions have finished. Use this method for
* playback of effects which require timing precision of less than a
* millisecond.
*
* Calling this method will terminate any waveform started with the play
* method. Calling the play method will terminate the active queued
* instruction and clear the instruction queue.
*
* Use isPlaying to check if all queued instructions have finished playing.
* This will return true even if the current instruction is "playing"
* silence.
*
* @param wave The waveform to use. For PC speaker, use square wave or
* silence.
* @param freq The frequency (in Hertz) to play.
* @param lengthus The length in microseconds for which to play the
* waveform.
*/
void playQueue(WaveForm wave, float freq, uint32 lengthus);
/** Stop the currently playing note after delay ms. */
void stop(int32 delay = 0);
/** Adjust the volume. */
void setVolume(byte volume);
bool isPlaying() const;
int readBuffer(int16 *buffer, const int numSamples);
bool isStereo() const { return false; }
bool endOfData() const { return false; }
bool endOfStream() const { return false; }
int getRate() const { return _rate; }
protected:
Common::Mutex _mutex;
int _rate;
WaveForm _wave;
bool _playForever;
uint32 _oscLength;
uint32 _oscSamples;
uint32 _remainingSamples;
uint32 _mixedSamples;
byte _volume;
// The queue of playback instructions.
Common::Queue<Command> *_commandQueue;
// True if a playback instruction is currently being executed. False if
// current playback was started by the play method (or if there is no
// playback at all).
bool _commandActive;
typedef int8 (*generatorFunc)(uint32, uint32);
static const generatorFunc generateWave[];
static int8 generateSquare(uint32 x, uint32 oscLength);
static int8 generateSine(uint32 x, uint32 oscLength);
static int8 generateSaw(uint32 x, uint32 oscLength);
static int8 generateTriangle(uint32 x, uint32 oscLength);
static int8 generateSilence(uint32 x, uint32 oscLength);
};
} // End of namespace Audio
#endif // AUDIO_SOFTSYNTH_PCSPEAKER_H
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