NES: add L I N E A R C O U N T E R effect

src/engine/dispatch.h

@@ -234,6 +234,8 @@ enum DivDispatchCmds {
   DIV_CMD_SNES_GLOBAL_VOL_LEFT,
   DIV_CMD_SNES_GLOBAL_VOL_RIGHT,
 
+  DIV_CMD_NES_LINEAR_LENGTH,
+
   DIV_ALWAYS_SET_VOLUME, // () -> alwaysSetVol
 
   DIV_CMD_MAX

src/engine/platform/nes.cpp

@@ -211,7 +211,7 @@ void DivPlatformNES::tick(bool sysTick) {
       chan[i].outVol=VOL_SCALE_LINEAR_BROKEN(chan[i].vol&15,MIN(15,chan[i].std.vol.val),15);
       if (chan[i].outVol<0) chan[i].outVol=0;
       if (i==2) { // triangle
-        rWrite(0x4000+i*4,(chan[i].outVol==0)?0:255);
+        rWrite(0x4000+i*4,(chan[i].outVol==0)?0:linearCount);
         chan[i].freqChanged=true;
       } else {
         rWrite(0x4000+i*4,(chan[i].envMode<<4)|chan[i].outVol|((chan[i].duty&3)<<6));
@@ -262,7 +262,7 @@ void DivPlatformNES::tick(bool sysTick) {
         //rWrite(16+i*5,chan[i].sweep);
       }
     }
-    if (i<2) if (chan[i].std.phaseReset.had) {
+    if (i<3) if (chan[i].std.phaseReset.had) {
       if (chan[i].std.phaseReset.val==1) {
         chan[i].freqChanged=true;
         chan[i].prevFreq=-1;
@@ -449,7 +449,7 @@ int DivPlatformNES::dispatch(DivCommand c) {
         chan[c.chan].outVol=chan[c.chan].vol;
       }
       if (c.chan==2) {
-        rWrite(0x4000+c.chan*4,0xff);
+        rWrite(0x4000+c.chan*4,linearCount);
       } else if (!parent->song.brokenOutVol2) {
         rWrite(0x4000+c.chan*4,(chan[c.chan].envMode<<4)|chan[c.chan].vol|((chan[c.chan].duty&3)<<6));
       }
@@ -481,7 +481,7 @@ int DivPlatformNES::dispatch(DivCommand c) {
         }
         if (chan[c.chan].active) {
           if (c.chan==2) {
-            rWrite(0x4000+c.chan*4,0xff);
+            rWrite(0x4000+c.chan*4,linearCount);
           } else {
             rWrite(0x4000+c.chan*4,(chan[c.chan].envMode<<4)|chan[c.chan].vol|((chan[c.chan].duty&3)<<6));
           }
@@ -557,6 +557,16 @@ int DivPlatformNES::dispatch(DivCommand c) {
       countMode=c.value;
       rWrite(0x4017,countMode?0x80:0);
       break;
+    case DIV_CMD_NES_LINEAR_LENGTH:
+      if (c.chan==2) {
+        linearCount=c.value;
+        if (chan[c.chan].active) {
+          rWrite(0x4000+c.chan*4,(chan[c.chan].outVol==0)?0:linearCount);
+          chan[c.chan].freqChanged=true;
+          chan[c.chan].prevFreq=-1;
+        }
+      }
+      break;
     case DIV_CMD_NES_DMC:
       rWrite(0x4011,c.value&0x7f);
       break;
@@ -682,6 +692,7 @@ void DivPlatformNES::reset() {
   goingToLoop=false;
   countMode=false;
   nextDPCMFreq=-1;
+  linearCount=255;
 
   if (useNP) {
     nes1_NP->Reset();

src/engine/platform/nes.h

@@ -52,6 +52,7 @@ class DivPlatformNES: public DivDispatch {
   unsigned char sampleBank;
   unsigned char writeOscBuf;
   unsigned char apuType;
+  unsigned char linearCount;
   signed char nextDPCMFreq;
   bool dpcmMode;
   bool dpcmModeDefault;

src/engine/playback.cpp

@@ -234,6 +234,8 @@ const char* cmdName[]={
   "SNES_GLOBAL_VOL_LEFT",
   "SNES_GLOBAL_VOL_RIGHT",
 
+  "NES_LINEAR_LENGTH",
+
   "ALWAYS_SET_VOLUME"
 };
 

src/engine/sysDef.cpp

@@ -713,6 +713,7 @@ void DivEngine::registerSystems() {
       {0x16, {DIV_CMD_NES_LENGTH, "16xx: Set length counter (refer to manual for a list of values)"}},
       {0x17, {DIV_CMD_NES_COUNT_MODE, "17xx: Set frame counter mode (0: 4-step, 1: 5-step)"}},
       {0x18, {DIV_CMD_SAMPLE_MODE, "18xx: Select PCM/DPCM mode (0: PCM; 1: DPCM)"}},
+      {0x19, {DIV_CMD_NES_LINEAR_LENGTH, "19xx: Set triangle linear counter (0 to 7F; 80 and higher halt)"}},
       {0x20, {DIV_CMD_SAMPLE_FREQ, "20xx: Set DPCM frequency (0 to F)"}}
     }
   );