add two new compatibility flags

proper noise range and duty macro is wave volume

papers/format.md

@@ -25,6 +25,9 @@ furthermore, an `or reserved` indicates this field is always present, but is res
 
 the format versions are:
 
+- 42: Furnace 0.5.5pre1
+- 41: Furnace 0.5.4
+- 40: Furnace 0.5.3
 - 39: Furnace 0.5.2
 - 38: Furnace 0.5.2pre2
 - 37: Furnace 0.5.2pre1
@@ -148,7 +151,9 @@ size | description
   1  | limit slides (>=36) or reserved
   1  | linear pitch (>=36) or reserved
   1  | loop modality (>=36) or reserved
- 17  | reserved
+  1  | proper noise layout (>=42) or reserved
+  1  | wave duty is volume (>=42) or reserved
+ 15  | reserved
  4?? | pointers to instruments
  4?? | pointers to wavetables
  4?? | pointers to samples

src/engine/engine.cpp

@@ -2077,6 +2077,10 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
       ds.linearPitch=true;
       ds.loopModality=0;
     }
+    if (ds.version<43) {
+      ds.properNoiseLayout=false;
+      ds.waveDutyIsVol=false;
+    }
 
     reader.readS(); // reserved
     int infoSeek=reader.readI();
@@ -2148,7 +2152,17 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
       ds.limitSlides=reader.readC();
       ds.linearPitch=reader.readC();
       ds.loopModality=reader.readC();
-      for (int i=0; i<17; i++) reader.readC();
+      if (ds.version>=43) {
+        ds.properNoiseLayout=reader.readC();
+      } else {
+        reader.readC();
+      }
+      if (ds.version>=43) {
+        ds.waveDutyIsVol=reader.readC();
+      } else {
+        reader.readC();
+      }
+      for (int i=0; i<15; i++) reader.readC();
     } else {
       for (int i=0; i<20; i++) reader.readC();
     }
@@ -2522,7 +2536,9 @@ SafeWriter* DivEngine::saveFur() {
   w->writeC(song.limitSlides);
   w->writeC(song.linearPitch);
   w->writeC(song.loopModality);
-  for (int i=0; i<17; i++) {
+  w->writeC(song.properNoiseLayout);
+  w->writeC(song.waveDutyIsVol);
+  for (int i=0; i<15; i++) {
     w->writeC(0);
   }
 

src/engine/engine.h

@@ -11,8 +11,8 @@
 #include <map>
 #include <queue>
 
-#define DIV_VERSION "0.5.4"
-#define DIV_ENGINE_VERSION 42
+#define DIV_VERSION "0.5.5pre1"
+#define DIV_ENGINE_VERSION 43
 
 enum DivStatusView {
   DIV_STATUS_NOTHING=0,

src/engine/platform/gb.cpp

@@ -144,6 +144,10 @@ void DivPlatformGB::tick() {
       DivInstrument* ins=parent->getIns(chan[i].ins);
       if (i!=2) {
         rWrite(16+i*5+1,((chan[i].duty&3)<<6)|(63-(ins->gb.soundLen&63)));
+      } else {
+        if (parent->song.waveDutyIsVol) {
+          rWrite(16+i*5+2,gbVolMap[(chan[i].std.duty&3)<<2]);
+        }
       }
     }
     if (chan[i].std.hadWave) {
@@ -164,7 +168,10 @@ void DivPlatformGB::tick() {
     if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {
       DivInstrument* ins=parent->getIns(chan[i].ins);
       if (i==3) { // noise
-        chan[i].freq=noiseTable[chan[i].baseFreq];
+        int ntPos=chan[i].baseFreq;
+        if (ntPos<0) ntPos=0;
+        if (ntPos>255) ntPos=255;
+        chan[i].freq=noiseTable[ntPos];
       } else {
         chan[i].freq=parent->calcFreq(chan[i].baseFreq,chan[i].pitch,true);
         if (chan[i].freq>2047) chan[i].freq=2047;

src/engine/platform/nes.cpp

@@ -73,7 +73,7 @@ void DivPlatformNES::acquire(short* bufL, short* bufR, size_t start, size_t len)
   }
 }
 
-static unsigned char noiseTable[256]={
+static unsigned char noiseTable[253]={
   6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 5, 4,
   15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4,
   15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4,
@@ -155,7 +155,10 @@ void DivPlatformNES::tick() {
     }
     if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {
       if (i==3) { // noise
-        chan[i].freq=noiseTable[chan[i].baseFreq];
+        int ntPos=chan[i].baseFreq;
+        if (ntPos<0) ntPos=0;
+        if (ntPos>252) ntPos=252;
+        chan[i].freq=(parent->song.properNoiseLayout)?(15-(chan[i].baseFreq&15)):(noiseTable[ntPos]);
       } else {
         chan[i].freq=parent->calcFreq(chan[i].baseFreq,chan[i].pitch,true);
         if (chan[i].freq>2047) chan[i].freq=2047;

src/engine/platform/pce.cpp

@@ -129,17 +129,23 @@ void DivPlatformPCE::tick() {
         if (chan[i].std.arpMode) {
           chan[i].baseFreq=NOTE_PERIODIC(chan[i].std.arp);
           // noise
-          chWrite(i,0x07,chan[i].noise?(0x80|noiseFreq[(chan[i].std.arp)%12]):0);
+          int noiseSeek=chan[i].std.arp;
+          if (noiseSeek<0) noiseSeek=0;
+          chWrite(i,0x07,chan[i].noise?(0x80|(parent->song.properNoiseLayout?(noiseSeek&31):noiseFreq[noiseSeek%12])):0);
         } else {
           chan[i].baseFreq=NOTE_PERIODIC(chan[i].note+chan[i].std.arp);
-          chWrite(i,0x07,chan[i].noise?(0x80|noiseFreq[(chan[i].note+chan[i].std.arp)%12]):0);
+          int noiseSeek=chan[i].note+chan[i].std.arp;
+          if (noiseSeek<0) noiseSeek=0;
+          chWrite(i,0x07,chan[i].noise?(0x80|(parent->song.properNoiseLayout?(noiseSeek&31):noiseFreq[noiseSeek%12])):0);
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
         chan[i].baseFreq=NOTE_PERIODIC(chan[i].note);
-        chWrite(i,0x07,chan[i].noise?(0x80|noiseFreq[chan[i].note%12]):0);
+        int noiseSeek=chan[i].note;
+        if (noiseSeek<0) noiseSeek=0;
+        chWrite(i,0x07,chan[i].noise?(0x80|(parent->song.properNoiseLayout?(noiseSeek&31):noiseFreq[noiseSeek%12])):0);
         chan[i].freqChanged=true;
       }
     }
@@ -248,7 +254,9 @@ int DivPlatformPCE::dispatch(DivCommand c) {
         chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
         chan[c.chan].freqChanged=true;
         chan[c.chan].note=c.value;
-        chWrite(c.chan,0x07,chan[c.chan].noise?(0x80|noiseFreq[chan[c.chan].note%12]):0);
+        int noiseSeek=chan[c.chan].note;
+        if (noiseSeek<0) noiseSeek=0;
+        chWrite(c.chan,0x07,chan[c.chan].noise?(0x80|(parent->song.properNoiseLayout?(noiseSeek&31):noiseFreq[noiseSeek%12])):0);
       }
       chan[c.chan].active=true;
       chan[c.chan].keyOn=true;

src/engine/song.h

@@ -215,6 +215,8 @@ struct DivSong {
   // 1: fake reset on loop
   // 2: don't do anything on loop
   unsigned char loopModality;
+  bool properNoiseLayout;
+  bool waveDutyIsVol;
 
   DivOrders orders;
   std::vector<DivInstrument*> ins;
@@ -263,7 +265,9 @@ struct DivSong {
     tuning(440.0f),
     limitSlides(false),
     linearPitch(true),
-    loopModality(0) {
+    loopModality(0),
+    properNoiseLayout(false),
+    waveDutyIsVol(false) {
     for (int i=0; i<32; i++) {
       system[i]=DIV_SYSTEM_NULL;
       systemVol[i]=64;

src/gui/gui.cpp

@@ -3845,17 +3845,40 @@ void FurnaceGUI::drawCompatFlags() {
   if (ImGui::Begin("Compatibility Flags",&compatFlagsOpen)) {
     ImGui::TextWrapped("these flags are stored in the song when saving in .fur format, and are automatically enabled when saving in .dmf format.");
     ImGui::Checkbox("Limit slide range",&e->song.limitSlides);
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("when enabled, slides are limited to a compatible range.\nmay cause problems with slides in negative octaves.");
+    }
     ImGui::Checkbox("Linear pitch control",&e->song.linearPitch);
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("linear pitch:\n- slides work in frequency/period space\n- E5xx and 04xx effects work in tonality space\nnon-linear pitch:\n- slides work in frequency/period space\n- E5xx and 04xx effects work on frequency/period space");
+    }
+    ImGui::Checkbox("Proper noise layout on NES and PC Engine",&e->song.properNoiseLayout);
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("use a proper noise channel note mapping (0-15) instead of a rather unusual compatible one.\nunlocks all noise frequencies on PC Engine.");
+    }
+    ImGui::Checkbox("Game Boy instrument duty is wave volume",&e->song.waveDutyIsVol);
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("if enabled, an instrument with duty macro in the wave channel will be mapped to wavetable volume.");
+    }
     ImGui::Text("Loop modality:");
     if (ImGui::RadioButton("Reset channels",e->song.loopModality==0)) {
       e->song.loopModality=0;
     }
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("select to reset channels on loop. may trigger a voltage click on every loop!");
+    }
     if (ImGui::RadioButton("Soft reset channels",e->song.loopModality==1)) {
       e->song.loopModality=1;
     }
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("select to turn channels off on loop.");
+    }
     if (ImGui::RadioButton("Do nothing",e->song.loopModality==2)) {
       e->song.loopModality=2;
     }
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("select to not reset channels on loop.");
+    }
   }
   ImGui::End();
 }