mirror of
https://github.com/libretro/scummvm.git
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131 lines
3.2 KiB
C++
131 lines
3.2 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
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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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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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* $URL$
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* $Id$
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*
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*/
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#include "sound/softsynth/pcspk.h"
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namespace Audio {
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const PCSpeaker::generatorFunc PCSpeaker::generateWave[] =
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{&PCSpeaker::generateSquare, &PCSpeaker::generateSine,
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&PCSpeaker::generateSaw, &PCSpeaker::generateTriangle};
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PCSpeaker::PCSpeaker(int rate) {
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_rate = rate;
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_wave = kWaveFormSquare;
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_playForever = false;
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_oscLength = 0;
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_oscSamples = 0;
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_remainingSamples = 0;
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_mixedSamples = 0;
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_volume = 255;
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}
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PCSpeaker::~PCSpeaker() {
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}
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void PCSpeaker::play(WaveForm wave, int freq, int32 length) {
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Common::StackLock lock(_mutex);
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assert((wave >= kWaveFormSquare) && (wave <= kWaveFormTriangle));
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_wave = wave;
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_oscLength = _rate / freq;
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_oscSamples = 0;
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if (length == -1) {
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_remainingSamples = 1;
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_playForever = true;
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} else {
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_remainingSamples = (_rate * length) / 1000;
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_playForever = false;
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}
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_mixedSamples = 0;
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}
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void PCSpeaker::stop(int32 delay) {
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Common::StackLock lock(_mutex);
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_remainingSamples = (_rate * delay) / 1000;
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_playForever = false;
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}
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void PCSpeaker::setVolume(byte volume) {
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_volume = volume;
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}
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bool PCSpeaker::isPlaying() const {
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return _remainingSamples != 0;
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}
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int PCSpeaker::readBuffer(int16 *buffer, const int numSamples) {
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Common::StackLock lock(_mutex);
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int i;
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for (i = 0; _remainingSamples && (i < numSamples); i++) {
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buffer[i] = generateWave[_wave](_oscSamples, _oscLength) * _volume;
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if (_oscSamples++ >= _oscLength)
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_oscSamples = 0;
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if (!_playForever)
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_remainingSamples--;
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_mixedSamples++;
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}
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// Clear the rest of the buffer
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if (i < numSamples)
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memset(buffer + i, 0, (numSamples - i) * sizeof(int16));
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return numSamples;
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}
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int8 PCSpeaker::generateSquare(uint32 x, uint32 oscLength) {
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return (x < (oscLength / 2)) ? 127 : -128;
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}
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int8 PCSpeaker::generateSine(uint32 x, uint32 oscLength) {
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if (oscLength == 0)
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return 0;
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// TODO: Maybe using a look-up-table would be better?
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return CLIP<int16>((int16) (128 * sin(2.0 * PI * x / oscLength)), -128, 127);
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}
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int8 PCSpeaker::generateSaw(uint32 x, uint32 oscLength) {
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if (oscLength == 0)
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return 0;
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return ((x * (65536 / oscLength)) >> 8) - 128;
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}
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int8 PCSpeaker::generateTriangle(uint32 x, uint32 oscLength) {
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if (oscLength == 0)
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return 0;
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int y = ((x * (65536 / (oscLength / 2))) >> 8) - 128;
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return (x <= (oscLength / 2)) ? y : (256 - y);
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}
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} // End of namespace Audio
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