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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 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.
*
* $URL$
* $Id$
*
*/
#include "sound/softsynth/pcspk.h"
namespace Audio {
const PCSpeaker::generatorFunc PCSpeaker::generateWave[] =
{&PCSpeaker::generateSquare, &PCSpeaker::generateSine,
&PCSpeaker::generateSaw, &PCSpeaker::generateTriangle};
PCSpeaker::PCSpeaker(int rate) {
_rate = rate;
_wave = kWaveFormSquare;
_playForever = false;
_oscLength = 0;
_oscSamples = 0;
_remainingSamples = 0;
_mixedSamples = 0;
_volume = 255;
}
PCSpeaker::~PCSpeaker() {
}
void PCSpeaker::play(WaveForm wave, int freq, int32 length) {
Common::StackLock lock(_mutex);
assert((wave >= kWaveFormSquare) && (wave <= kWaveFormTriangle));
_wave = wave;
_oscLength = _rate / freq;
_oscSamples = 0;
if (length == -1) {
_remainingSamples = 1;
_playForever = true;
} else {
_remainingSamples = (_rate * length) / 1000;
_playForever = false;
}
_mixedSamples = 0;
}
void PCSpeaker::stop(int32 delay) {
Common::StackLock lock(_mutex);
_remainingSamples = (_rate * delay) / 1000;
_playForever = false;
}
void PCSpeaker::setVolume(byte volume) {
_volume = volume;
}
int PCSpeaker::readBuffer(int16 *buffer, const int numSamples) {
Common::StackLock lock(_mutex);
int i;
for (i = 0; _remainingSamples && (i < numSamples); i++) {
buffer[i] = generateWave[_wave](_oscSamples, _oscLength) * _volume;
if (_oscSamples++ >= _oscLength)
_oscSamples = 0;
if (!_playForever)
_remainingSamples--;
_mixedSamples++;
}
// Clear the rest of the buffer
if (i < numSamples)
memset(buffer + i, 0, (numSamples - i) * sizeof(int16));
return numSamples;
}
int8 PCSpeaker::generateSquare(uint32 x, uint32 oscLength) {
return (x < (oscLength / 2)) ? 127 : -128;
}
int8 PCSpeaker::generateSine(uint32 x, uint32 oscLength) {
if (oscLength == 0)
return 0;
// TODO: Maybe using a look-up-table would be better?
return CLIP<int16>((int16) (128 * sin(2.0 * M_PI * x / oscLength)), -128, 127);
}
int8 PCSpeaker::generateSaw(uint32 x, uint32 oscLength) {
if (oscLength == 0)
return 0;
return ((x * (65536 / oscLength)) >> 8) - 128;
}
int8 PCSpeaker::generateTriangle(uint32 x, uint32 oscLength) {
if (oscLength == 0)
return 0;
int y = ((x * (65536 / (oscLength / 2))) >> 8) - 128;
return (x <= (oscLength / 2)) ? y : (256 - y);
}
} // End of namespace Audio
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