Add generic PCM DAC system

For use with NGP DAC and some arcade system combos

src/engine/platform/pcmdac.h

@@ -0,0 +1,99 @@
+/**
+ * Furnace Tracker - multi-system chiptune tracker
+ * Copyright (C) 2021-2022 tildearrow and contributors
+ *
+ * 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 2 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef _PCM_DAC_H
+#define _PCM_DAC_H
+
+#include "../dispatch.h"
+#include <queue>
+#include "../macroInt.h"
+#include "../waveSynth.h"
+
+class DivPlatformPCMDAC: public DivDispatch {
+  struct Channel {
+    int freq, baseFreq, pitch, pitch2;
+    unsigned int audLoc;
+    unsigned short audLen;
+    unsigned int audPos;
+    int audSub;
+    int sample, wave, ins;
+    int note;
+    int panL, panR;
+    bool active, insChanged, freqChanged, keyOn, keyOff, inPorta, useWave, setPos;
+    int vol, envVol;
+    DivMacroInt std;
+    DivWaveSynth ws;
+    void macroInit(DivInstrument* which) {
+      std.init(which);
+      pitch2=0;
+    }
+    Channel():
+      freq(0),
+      baseFreq(0),
+      pitch(0),
+      pitch2(0),
+      audLoc(0),
+      audLen(0),
+      audPos(0),
+      audSub(0),
+      sample(-1),
+      wave(-1),
+      ins(-1),
+      panL(255),
+      panR(255),
+      note(0),
+      active(false),
+      insChanged(true),
+      freqChanged(false),
+      keyOn(false),
+      keyOff(false),
+      inPorta(false),
+      useWave(false),
+      setPos(false),
+      vol(255),
+      envVol(64) {}
+  };
+  Channel chan;
+  DivDispatchOscBuffer* oscBuf;
+  bool isMuted;
+  int outDepth;
+  bool outStereo;
+
+  friend void putDispatchChan(void*,int,int);
+
+  public:
+    void acquire(short* bufL, short* bufR, size_t start, size_t len);
+    int dispatch(DivCommand c);
+    void* getChanState(int chan);
+    DivDispatchOscBuffer* getOscBuffer(int chan);
+    void reset();
+    void forceIns();
+    void tick(bool sysTick=true);
+    void muteChannel(int ch, bool mute);
+    bool isStereo();
+    DivMacroInt* getChanMacroInt(int ch);
+    void setFlags(unsigned int flags);
+    void notifyInsChange(int ins);
+    void notifyWaveChange(int wave);
+    void notifyInsDeletion(void* ins);
+    int init(DivEngine* parent, int channels, int sugRate, unsigned int flags);
+    void quit();
+};
+
+#endif