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