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audio/softsynth/fmtowns_pc98/pcm_common.h

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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/>.
+ *
+ */
+
+#ifndef PCM_COMMON_H
+#define PCM_COMMON_H
+
+#include "common/scummsys.h"
+
+// The SegaCD and the FM-Towns have (almost) the same PCM sound chip. And while each platform has low-level driver
+// stuff going on top of that it still makes sense to identify and abstract some commmon code.
+
+class PCMChannel_Base {
+public:
+	PCMChannel_Base();
+	virtual ~PCMChannel_Base();
+
+	virtual void clear();
+
+	void updateOutput();
+	int32 currentSampleLeft();
+	int32 currentSampleRight();
+
+	virtual bool isPlaying() const = 0;
+	bool isActive() const;
+	void activate();
+	void deactivate();
+
+protected:
+	void setData(const int8 *data, uint32 dataEnd, uint32 dataStart = 0);
+	void setVolume(uint8 vol);
+	void setPanPos(uint8 setPanPos);
+	void setupLoop(uint32 loopStart, uint32 loopLen);
+	void setRate(uint16 rate);
+
+private:
+	virtual void stopInternal() = 0;
+
+	uint8 _panLeft;
+	uint8 _panRight;
+	uint8 _vol;
+	bool _activeOutput;
+
+	uint32 _loopStart;
+	uint32 _loopLen;
+	uint32 _dataEnd;
+	uint32 _pos;
+	uint16 _step;
+	const int8 *_data;
+};
+
+class PCMDevice_Base {
+public:
+	PCMDevice_Base(int samplingRate, int deviceVolume, int numChannels);
+	~PCMDevice_Base();
+
+	void assignChannel(uint8 id, PCMChannel_Base *const chan);
+	void setMusicVolume(uint16 vol);
+	void setSfxVolume(uint16 vol);
+	void setSfxChanMask(int mask);
+
+	void readBuffer(int32 *buffer, uint32 bufferSize);
+
+private:
+	const uint32 _intRate;
+	const uint32 _extRate;
+	const int _deviceVolume;
+	uint32 _timer;
+
+	uint16 _musicVolume;
+	uint16 _sfxVolume;
+	int _pcmSfxChanMask;
+
+	PCMChannel_Base **_channels;
+	const int _numChannels;
+};
+
+#endif