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engines/scumm/players/player_mod.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 "scumm/players/player_mod.h"
+#include "audio/mixer.h"
+#include "audio/rate.h"
+#include "audio/decoders/raw.h"
+
+namespace Scumm {
+
+Player_MOD::Player_MOD(Audio::Mixer *mixer)
+	: _mixer(mixer), _sampleRate(mixer->getOutputRate()) {
+	int i;
+	_mixamt = 0;
+	_mixpos = 0;
+
+	for (i = 0; i < MOD_MAXCHANS; i++) {
+		_channels[i].id = 0;
+		_channels[i].vol = 0;
+		_channels[i].freq = 0;
+		_channels[i].input = nullptr;
+		_channels[i].ctr = 0;
+		_channels[i].pos = 0;
+	}
+
+	_playproc = nullptr;
+	_playparam = nullptr;
+
+	_mixer->playStream(Audio::Mixer::kPlainSoundType, &_soundHandle, this, -1, Audio::Mixer::kMaxChannelVolume, 0, DisposeAfterUse::NO, true);
+}
+
+Player_MOD::~Player_MOD() {
+	_mixer->stopHandle(_soundHandle);
+	for (int i = 0; i < MOD_MAXCHANS; i++) {
+		if (!_channels[i].id)
+			continue;
+		delete _channels[i].input;
+	}
+}
+
+void Player_MOD::setMusicVolume(int vol) {
+	_maxvol = vol;
+}
+
+void Player_MOD::setUpdateProc(ModUpdateProc *proc, void *param, int freq) {
+	Common::StackLock lock(_mutex);
+	_playproc = proc;
+	_playparam = param;
+	_mixamt = _sampleRate / freq;
+}
+void Player_MOD::clearUpdateProc() {
+	Common::StackLock lock(_mutex);
+	_playproc = nullptr;
+	_playparam = nullptr;
+	_mixamt = 0;
+}
+
+void Player_MOD::startChannel(int id, void *data, int size, int rate, uint8 vol, int loopStart, int loopEnd, int8 pan) {
+	int i;
+	if (id == 0)
+		error("player_mod - attempted to start channel id 0");
+
+	Common::StackLock lock(_mutex);
+	for (i = 0; i < MOD_MAXCHANS; i++) {
+		if (!_channels[i].id)
+			break;
+	}
+	if (i == MOD_MAXCHANS) {
+		warning("player_mod - too many music channels playing (%i max)",MOD_MAXCHANS);
+		return;
+	}
+	_channels[i].id = id;
+	_channels[i].vol = vol;
+	_channels[i].pan = pan;
+	_channels[i].freq = rate;
+	_channels[i].ctr = 0;
+
+	Audio::SeekableAudioStream *stream = Audio::makeRawStream((const byte *)data, size, rate, 0);
+	if (loopStart != loopEnd) {
+		_channels[i].input = new Audio::SubLoopingAudioStream(stream, 0, Audio::Timestamp(0, loopStart, rate), Audio::Timestamp(0, loopEnd, rate));
+	} else {
+		_channels[i].input = stream;
+	}
+
+	// read the first sample
+	_channels[i].input->readBuffer(&_channels[i].pos, 1);
+}
+
+void Player_MOD::stopChannel(int id) {
+	if (id == 0)
+		error("player_mod - attempted to stop channel id 0");
+
+	Common::StackLock lock(_mutex);
+	for (int i = 0; i < MOD_MAXCHANS; i++) {
+		if (_channels[i].id == id) {
+			delete _channels[i].input;
+			_channels[i].input = nullptr;
+			_channels[i].id = 0;
+			_channels[i].vol = 0;
+			_channels[i].freq = 0;
+			_channels[i].ctr = 0;
+			_channels[i].pos = 0;
+		}
+	}
+}
+void Player_MOD::setChannelVol(int id, uint8 vol) {
+	if (id == 0)
+		error("player_mod - attempted to set volume for channel id 0");
+
+	Common::StackLock lock(_mutex);
+	for (int i = 0; i < MOD_MAXCHANS; i++) {
+		if (_channels[i].id == id) {
+			_channels[i].vol = vol;
+			break;
+		}
+	}
+}
+
+void Player_MOD::setChannelPan(int id, int8 pan) {
+	if (id == 0)
+		error("player_mod - attempted to set pan for channel id 0");
+
+	Common::StackLock lock(_mutex);
+	for (int i = 0; i < MOD_MAXCHANS; i++) {
+		if (_channels[i].id == id) {
+			_channels[i].pan = pan;
+			break;
+		}
+	}
+}
+
+void Player_MOD::setChannelFreq(int id, int freq) {
+	if (id == 0)
+		error("player_mod - attempted to set frequency for channel id 0");
+
+	Common::StackLock lock(_mutex);
+	for (int i = 0; i < MOD_MAXCHANS; i++) {
+		if (_channels[i].id == id) {
+			if (freq > 31400)	// this is about as high as WinUAE goes
+				freq = 31400;	// can't easily verify on my own Amiga
+			_channels[i].freq = freq;
+			break;
+		}
+	}
+}
+
+void Player_MOD::do_mix(int16 *data, uint len) {
+	int i;
+	int dpos = 0;
+	uint dlen = 0;
+	memset(data, 0, 2 * len * sizeof(int16));
+	while (len) {
+		if (_playproc) {
+			dlen = _mixamt - _mixpos;
+			if (!_mixpos)
+				_playproc(_playparam);
+			if (dlen <= len) {
+				_mixpos = 0;
+				len -= dlen;
+			} else {
+				_mixpos += len;
+				dlen = len;
+				len = 0;
+			}
+		} else {
+			dlen = len;
+			len = 0;
+		}
+		for (i = 0; i < MOD_MAXCHANS; i++) {
+			if (_channels[i].id) {
+				Audio::st_volume_t vol_l = (127 - _channels[i].pan) * _channels[i].vol / 127;
+				Audio::st_volume_t vol_r = (127 + _channels[i].pan) * _channels[i].vol / 127;
+				for (uint j = 0; j < dlen; j++) {
+					// simple linear resample, unbuffered
+					int delta = (uint32)(_channels[i].freq * 0x10000) / _sampleRate;
+					uint16 cfrac = ~_channels[i].ctr & 0xFFFF;
+					if (_channels[i].ctr + delta < 0x10000)
+						cfrac = delta;
+					_channels[i].ctr += delta;
+					int32 cpos = _channels[i].pos * cfrac / 0x10000;
+					while (_channels[i].ctr >= 0x10000) {
+						if (_channels[i].input->readBuffer(&_channels[i].pos, 1) != 1) {	// out of data
+							stopChannel(_channels[i].id);
+							goto skipchan;	// exit 2 loops at once
+						}
+						_channels[i].ctr -= 0x10000;
+						if (_channels[i].ctr > 0x10000)
+							cpos += _channels[i].pos;
+						else
+							cpos += (int32)(_channels[i].pos * (_channels[i].ctr & 0xFFFF)) / 0x10000;
+					}
+					int16 pos = 0;
+					// if too many samples play in a row, the calculation below will overflow and clip
+					// so try and split it up into pieces it can manage comfortably
+					while (cpos < -0x8000) {
+						pos -= 0x80000000 / delta;
+						cpos += 0x8000;
+					}
+					while (cpos > 0x7FFF) {
+						pos += 0x7FFF0000 / delta;
+						cpos -= 0x7FFF;
+					}
+					pos += cpos * 0x10000 / delta;
+					Audio::clampedAdd(data[(dpos + j) * 2 + 0], pos * vol_l / Audio::Mixer::kMaxMixerVolume);
+					Audio::clampedAdd(data[(dpos + j) * 2 + 1], pos * vol_r / Audio::Mixer::kMaxMixerVolume);
+				}
+			}
+skipchan:		;	// channel ran out of data
+		}
+		dpos += dlen;
+	}
+}
+
+} // End of namespace Scumm