Initial commit

audio/softsynth/fmtowns_pc98/pcm_common.cpp

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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/softsynth/fmtowns_pc98/pcm_common.h"
+#include "audio/mixer.h"
+
+PCMChannel_Base::PCMChannel_Base() : _vol(0), _data(nullptr), _dataEnd(0), _loopLen(0), _pos(0), _loopStart(0), _step(0), _panLeft(7), _panRight(7), _activeOutput(false)  {
+}
+
+PCMChannel_Base::~PCMChannel_Base() {
+	clear();
+}
+
+void PCMChannel_Base::clear() {
+	_vol = 0;
+	_data = nullptr;
+	_dataEnd = 0;
+	_loopLen = 0;
+	_pos = 0;
+	_loopStart = 0;
+	_step = 0;
+	_panLeft = _panRight = 7;
+	_activeOutput = false;
+}
+
+void PCMChannel_Base::updateOutput() {
+	if (!isPlaying())
+		return;
+
+	_pos += _step;
+
+	if (_pos >= _dataEnd) {
+		if (_loopStart != _dataEnd) {
+			_pos = _loopStart;
+			_dataEnd = _loopStart + _loopLen;
+		} else {
+			_pos = 0;
+			stopInternal();
+		}
+	}
+}
+
+int32 PCMChannel_Base::currentSampleLeft() {
+	return (isActive() && _panLeft) ? (((_data[_pos >> 11] * _vol) * _panLeft) >> 3) : 0;
+}
+
+int32 PCMChannel_Base::currentSampleRight() {
+	return (isActive() && _panRight) ? (((_data[_pos >> 11] * _vol) * _panRight) >> 3) : 0;
+}
+
+bool PCMChannel_Base::isActive() const {
+	return _activeOutput;
+}
+
+void PCMChannel_Base::activate() {
+	_activeOutput = true;
+}
+
+void PCMChannel_Base::deactivate() {
+	_activeOutput = false;
+}
+
+void PCMChannel_Base::setData(const int8 *data, uint32 dataEnd, uint32 dataStart) {
+	_data = data;
+	_dataEnd = dataEnd;
+	_pos = dataStart;
+}
+
+void PCMChannel_Base::setVolume(uint8 vol) {
+	_vol = vol;
+}
+
+void PCMChannel_Base::setPanPos(uint8 pan) {
+	_panLeft = pan & 0x0f;
+	_panRight = pan >> 4;
+}
+
+void PCMChannel_Base::setupLoop(uint32 loopStart, uint32 loopLen) {
+	_loopStart = loopStart << 11;
+	_loopLen = loopLen << 11;
+}
+
+void PCMChannel_Base::setRate(uint16 rate) {
+	_step = rate;
+}
+
+PCMDevice_Base::PCMDevice_Base(int samplingRate, int deviceVolume, int numChannels) : _numChannels(numChannels), _deviceVolume(deviceVolume), _intRate((7670454 << 8) / samplingRate),
+	_extRate(72 << 8), _timer(0), _musicVolume(Audio::Mixer::kMaxMixerVolume), _sfxVolume(Audio::Mixer::kMaxMixerVolume), _pcmSfxChanMask(0) {
+	_channels = new PCMChannel_Base*[numChannels];
+}
+
+PCMDevice_Base::~PCMDevice_Base() {
+	delete[] _channels;
+}
+
+void PCMDevice_Base::assignChannel(uint8 id, PCMChannel_Base *const chan) {
+	assert(id < _numChannels);
+	_channels[id] = chan;
+}
+
+void PCMDevice_Base::setMusicVolume(uint16 vol) {
+	_musicVolume = vol;
+}
+
+void PCMDevice_Base::setSfxVolume(uint16 vol) {
+	_sfxVolume = vol;
+}
+
+void PCMDevice_Base::setSfxChanMask(int mask) {
+	_pcmSfxChanMask = mask;
+}
+
+void PCMDevice_Base::readBuffer(int32 *buffer, uint32 bufferSize) {
+	for (uint32 i = 0; i < bufferSize; i++) {
+		_timer += _extRate;
+		while (_timer >= _intRate) {
+			_timer -= _intRate;
+
+			for (int ii = 0; ii < 8; ii++)
+				_channels[ii]->updateOutput();
+		}
+
+		int32 finOutL = 0;
+		int32 finOutR = 0;
+
+		for (int ii = 0; ii < _numChannels; ii++) {
+			if (_channels[ii]->isActive()) {
+				int32 oL = _channels[ii]->currentSampleLeft();
+				int32 oR = _channels[ii]->currentSampleRight();
+				if ((1 << ii) & (~_pcmSfxChanMask)) {
+					oL = (oL * _musicVolume) / Audio::Mixer::kMaxMixerVolume;
+					oR = (oR * _musicVolume) / Audio::Mixer::kMaxMixerVolume;
+				}
+				if ((1 << ii) & _pcmSfxChanMask) {
+					oL = (oL * _sfxVolume) / Audio::Mixer::kMaxMixerVolume;
+					oR = (oR * _sfxVolume) / Audio::Mixer::kMaxMixerVolume;
+				}
+				finOutL += oL;
+				finOutR += oR;
+
+				if (!_channels[ii]->isPlaying())
+					_channels[ii]->deactivate();
+			}
+		}
+
+		buffer[i << 1] += ((finOutL * _deviceVolume) >> 7);
+		buffer[(i << 1) + 1] += ((finOutR * _deviceVolume) >> 7);
+	}
+}