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127 lines
3.7 KiB
C++
127 lines
3.7 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef AUDIO_SOFTSYNTH_PCSPK_H
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#define AUDIO_SOFTSYNTH_PCSPK_H
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#include "audio/audiostream.h"
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#include "common/mutex.h"
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#include "common/queue.h"
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namespace Audio {
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class PCSpeaker : public AudioStream {
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public:
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enum WaveForm {
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kWaveFormSquare = 0,
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kWaveFormSine,
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kWaveFormSaw,
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kWaveFormTriangle,
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kWaveFormSilence
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};
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protected:
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// PC speaker instruction: play this waveform at frequency x for y microseconds.
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struct Command {
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WaveForm waveForm;
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float frequency;
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uint32 length;
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Command(WaveForm waveForm, float frequency, uint32 length);
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};
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public:
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PCSpeaker(int rate = 44100);
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~PCSpeaker();
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/** Play a note for length ms.
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*
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* If length is negative, play until told to stop.
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*/
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void play(WaveForm wave, int freq, int32 length);
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/**
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* Queue the specified playback instruction. It will be executed when all
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* previously queued instructions have finished. Use this method for
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* playback of effects which require timing precision of less than a
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* millisecond.
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*
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* Calling this method will terminate any waveform started with the play
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* method. Calling the play method will terminate the active queued
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* instruction and clear the instruction queue.
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*
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* Use isPlaying to check if all queued instructions have finished playing.
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* This will return true even if the current instruction is "playing"
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* silence.
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*
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* @param wave The waveform to use. For PC speaker, use square wave or
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* silence.
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* @param freq The frequency (in Hertz) to play.
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* @param lengthus The length in microseconds for which to play the
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* waveform.
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*/
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void playQueue(WaveForm wave, float freq, uint32 lengthus);
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/** Stop the currently playing note after delay ms. */
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void stop(int32 delay = 0);
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/** Adjust the volume. */
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void setVolume(byte volume);
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bool isPlaying() const;
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int readBuffer(int16 *buffer, const int numSamples);
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bool isStereo() const { return false; }
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bool endOfData() const { return false; }
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bool endOfStream() const { return false; }
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int getRate() const { return _rate; }
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protected:
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Common::Mutex _mutex;
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int _rate;
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WaveForm _wave;
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bool _playForever;
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uint32 _oscLength;
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uint32 _oscSamples;
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uint32 _remainingSamples;
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uint32 _mixedSamples;
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byte _volume;
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// The queue of playback instructions.
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Common::Queue<Command> *_commandQueue;
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// True if a playback instruction is currently being executed. False if
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// current playback was started by the play method (or if there is no
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// playback at all).
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bool _commandActive;
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typedef int8 (*generatorFunc)(uint32, uint32);
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static const generatorFunc generateWave[];
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static int8 generateSquare(uint32 x, uint32 oscLength);
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static int8 generateSine(uint32 x, uint32 oscLength);
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static int8 generateSaw(uint32 x, uint32 oscLength);
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static int8 generateTriangle(uint32 x, uint32 oscLength);
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static int8 generateSilence(uint32 x, uint32 oscLength);
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};
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} // End of namespace Audio
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#endif // AUDIO_SOFTSYNTH_PCSPEAKER_H
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