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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/>.
*
*/
#include "audio/cms.h"
#include "audio/softsynth/cms.h"
namespace CMS {
CMS *Config::create() {
// For now this is fixed to the DOSBox emulator.
return new DOSBoxCMS();
}
bool CMS::_hasInstance = false;
CMS::CMS() {
if (_hasInstance)
error("There are multiple CMS output instances running.");
_hasInstance = true;
}
CMS::~CMS() {
_hasInstance = false;
}
void CMS::start(TimerCallback *callback, int timerFrequency) {
_callback.reset(callback);
startCallbacks(timerFrequency);
}
void CMS::stop() {
stopCallbacks();
_callback.reset();
}
EmulatedCMS::EmulatedCMS() :
_nextTick(0),
_samplesPerTick(0),
_baseFreq(0),
_handle(new Audio::SoundHandle()) { }
EmulatedCMS::~EmulatedCMS() {
// Stop callbacks, just in case. If it's still playing at this
// point, there's probably a bigger issue, though. The subclass
// needs to call stop() or the pointer can still use be used in
// the mixer thread at the same time.
stop();
delete _handle;
}
int EmulatedCMS::readBuffer(int16 *buffer, const int numSamples) {
int len = numSamples / 2;
int step;
do {
step = len;
if (step > (_nextTick >> FIXP_SHIFT))
step = (_nextTick >> FIXP_SHIFT);
generateSamples(buffer, step);
_nextTick -= step << FIXP_SHIFT;
if (!(_nextTick >> FIXP_SHIFT)) {
if (_callback && _callback->isValid())
(*_callback)();
_nextTick += _samplesPerTick;
}
buffer += step * 2;
len -= step;
} while (len);
return numSamples;
}
int EmulatedCMS::getRate() const {
return g_system->getMixer()->getOutputRate();
}
bool EmulatedCMS::endOfData() const {
return false;
}
bool EmulatedCMS::isStereo() const {
return true;
}
void EmulatedCMS::startCallbacks(int timerFrequency) {
setCallbackFrequency(timerFrequency);
g_system->getMixer()->playStream(Audio::Mixer::kMusicSoundType, _handle, this, -1, Audio::Mixer::kMaxChannelVolume, 0, DisposeAfterUse::NO, true);
}
void EmulatedCMS::stopCallbacks() {
g_system->getMixer()->stopHandle(*_handle);
}
void EmulatedCMS::setCallbackFrequency(int timerFrequency) {
_baseFreq = timerFrequency;
assert(_baseFreq != 0);
int d = getRate() / _baseFreq;
int r = getRate() % _baseFreq;
// This is equivalent to (getRate() << FIXP_SHIFT) / BASE_FREQ
// but less prone to arithmetic overflow.
_samplesPerTick = (d << FIXP_SHIFT) + (r << FIXP_SHIFT) / _baseFreq;
}
} // End of namespace CMS
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