VGM export: add "trailing ticks" option

issue #695

src/engine/engine.h

@@ -100,6 +100,7 @@ struct DivChannelState {
   unsigned char arp, arpStage, arpTicks, panL, panR, panRL, panRR;
   bool doNote, legato, portaStop, keyOn, keyOff, nowYouCanStop, stopOnOff;
   bool arpYield, delayLocked, inPorta, scheduledSlideReset, shorthandPorta, wasShorthandPorta, noteOnInhibit, resetArp;
+  bool wentThroughNote, goneThroughNote;
 
   int midiNote, curMidiNote, midiPitch;
   size_t midiAge;
@@ -152,6 +153,8 @@ struct DivChannelState {
     wasShorthandPorta(false),
     noteOnInhibit(false),
     resetArp(false),
+    wentThroughNote(false),
+    goneThroughNote(false),
     midiNote(-1),
     curMidiNote(-1),
     midiPitch(-1),
@@ -524,7 +527,12 @@ class DivEngine {
     // specify system to build ROM for.
     SafeWriter* buildROM(int sys);
     // dump to VGM.
-    SafeWriter* saveVGM(bool* sysToExport=NULL, bool loop=true, int version=0x171, bool patternHints=false, bool directStream=false);
+    // set trailingTicks to:
+    // - 0 to add one tick of trailing
+    // - x to add x+1 ticks of trailing
+    // - -1 to auto-determine trailing
+    // - -2 to add a whole loop of trailing
+    SafeWriter* saveVGM(bool* sysToExport=NULL, bool loop=true, int version=0x171, bool patternHints=false, bool directStream=false, int trailingTicks=-1);
     // dump to ZSM.
     SafeWriter* saveZSM(unsigned int zsmrate=60, bool loop=true);
     // dump command stream.

src/engine/playback.cpp

@@ -957,6 +957,8 @@ void DivEngine::processRow(int i, bool afterDelay) {
         }
       } else if (!chan[i].noteOnInhibit) {
         dispatchCmd(DivCommand(DIV_CMD_NOTE_ON,i,chan[i].note,chan[i].volume>>8));
+        chan[i].goneThroughNote=true;
+        chan[i].wentThroughNote=true;
         keyHit[i]=true;
       }
     }

src/engine/vgmOps.cpp

@@ -952,7 +952,7 @@ void DivEngine::performVGMWrite(SafeWriter* w, DivSystem sys, DivRegWrite& write
   chipVol.push_back((_id)|(0x80000100)|(((unsigned int)_vol)<<16)); \
 }
 
-SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version, bool patternHints, bool directStream) {
+SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version, bool patternHints, bool directStream, int trailingTicks) {
   if (version<0x150) {
     lastError="VGM version is too low";
     return NULL;
@@ -1037,7 +1037,8 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version, bool p
   int chipAccounting=0;
 
   int loopPos=-1;
-  int loopTick=-1;
+  int loopTickSong=-1;
+  int songTick=0;
 
   unsigned int sampleOff8[256];
   unsigned int sampleOffSegaPCM[256];
@@ -1063,6 +1064,11 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version, bool p
   std::vector<DivDelayedWrite> delayedWrites[DIV_MAX_CHIPS];
   std::vector<std::pair<int,DivDelayedWrite>> sortedWrites;
   std::vector<size_t> tickPos;
+  std::vector<int> tickSample;
+
+  bool trailing=false;
+  bool beenOneLoopAlready=false;
+  int countDown=MAX(0,trailingTicks)+1;
 
   for (int i=0; i<DIV_MAX_CHANS; i++) {
     loopTimer[i]=0;
@@ -2103,11 +2109,14 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version, bool p
   playSub(false);
   size_t tickCount=0;
   bool writeLoop=false;
+  bool alreadyWroteLoop=false;
   int ord=-1;
   int exportChans=0;
   for (int i=0; i<chans; i++) {
     if (!willExport[dispatchOfChan[i]]) continue;
     exportChans++;
+    chan[i].wentThroughNote=false;
+    chan[i].goneThroughNote=false;
   }
   while (!done) {
     if (loopPos==-1) {
@@ -2115,8 +2124,45 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version, bool p
         writeLoop=true;
       }
     }
+    songTick++;
     tickPos.push_back(w->tell());
-    if (nextTick(false,true) || !playing) {
+    tickSample.push_back(tickCount);
+    if (nextTick(false,true)) {
+      if (trailing) beenOneLoopAlready=true;
+      trailing=true;
+      for (int i=0; i<chans; i++) {
+        if (!willExport[dispatchOfChan[i]]) continue;
+        chan[i].wentThroughNote=false;
+      }
+    }
+    if (trailing) {
+      switch (trailingTicks) {
+        case -1: { // automatic
+          bool stillHaveTo=false;
+          for (int i=0; i<chans; i++) {
+            if (!willExport[dispatchOfChan[i]]) continue;
+            if (!chan[i].goneThroughNote) continue;
+            if (!chan[i].wentThroughNote) {
+              stillHaveTo=true;
+              break;
+            }
+          }
+          if (!stillHaveTo) countDown=0;
+          break;
+        }
+        case -2: // one loop
+          break;
+        default: // custom
+          countDown--;
+          break;
+      }
+      if (song.loopModality!=2) countDown=0;
+
+      if (countDown>0 && !beenOneLoopAlready) {
+        loopTickSong++;
+      }
+    }
+    if (countDown<=0 || !playing || beenOneLoopAlready) {
       done=true;
       if (!loop) {
         for (int i=0; i<song.systemLen; i++) {
@@ -2275,10 +2321,11 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version, bool p
       }
       tickCount+=totalWait;
     }
-    if (writeLoop) {
+    if (writeLoop && !alreadyWroteLoop) {
       writeLoop=false;
+      alreadyWroteLoop=true;
       loopPos=w->tell();
-      loopTick=tickCount;
+      loopTickSong=songTick;
     }
   }
   // end of song
@@ -2333,9 +2380,16 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version, bool p
     if (loopPos==-1) {
       w->writeI(0);
       w->writeI(0);
+    } else if (loopTickSong<0 || loopTickSong>(int)tickPos.size()) {
+      logW("loopTickSong out of range! %d>%d",loopTickSong,(int)tickPos.size());
+      w->writeI(0);
+      w->writeI(0);
     } else {
-      w->writeI(loopPos-0x1c);
+      int realLoopTick=tickSample[loopTickSong];
-      w->writeI(tickCount-loopTick);
+      int realLoopPos=tickPos[loopTickSong];
+      logI("tickCount-realLoopTick: %d. realLoopPos: %d",tickCount-realLoopTick,realLoopPos);
+      w->writeI(realLoopPos-0x1c);
+      w->writeI(tickCount-realLoopTick);
     }
   } else {
     w->writeI(0);

src/gui/gui.cpp

@@ -3530,6 +3530,24 @@ bool FurnaceGUI::loop() {
             ImGui::EndCombo();
           }
           ImGui::Checkbox("loop",&vgmExportLoop);
+          if (vgmExportLoop && e->song.loopModality==2) {
+            ImGui::Text("trailing ticks:");
+            if (ImGui::RadioButton("auto-detect",vgmExportTrailingTicks==-1)) {
+              vgmExportTrailingTicks=-1;
+            }
+            if (ImGui::RadioButton("one loop",vgmExportTrailingTicks==-2)) {
+              vgmExportTrailingTicks=-2;
+            }
+            if (ImGui::RadioButton("custom",vgmExportTrailingTicks>=0)) {
+              vgmExportTrailingTicks=0;
+            }
+            if (vgmExportTrailingTicks>=0) {
+              ImGui::SameLine();
+              if (ImGui::InputInt("##TrailTicks",&vgmExportTrailingTicks,1,100)) {
+                if (vgmExportTrailingTicks<0) vgmExportTrailingTicks=0;
+              }
+            }
+          }
           ImGui::Checkbox("add pattern change hints",&vgmExportPatternHints);
           if (ImGui::IsItemHovered()) {
             ImGui::SetTooltip(
@@ -4463,7 +4481,7 @@ bool FurnaceGUI::loop() {
               break;
             }
             case GUI_FILE_EXPORT_VGM: {
-              SafeWriter* w=e->saveVGM(willExport,vgmExportLoop,vgmExportVersion,vgmExportPatternHints,vgmExportDirectStream);
+              SafeWriter* w=e->saveVGM(willExport,vgmExportLoop,vgmExportVersion,vgmExportPatternHints,vgmExportDirectStream,vgmExportTrailingTicks);
               if (w!=NULL) {
                 FILE* f=ps_fopen(copyOfName.c_str(),"wb");
                 if (f!=NULL) {
@@ -5837,6 +5855,7 @@ FurnaceGUI::FurnaceGUI():
   snesFilterHex(false),
   mobileEdit(false),
   vgmExportVersion(0x171),
+  vgmExportTrailingTicks(-1),
   drawHalt(10),
   zsmExportTickRate(60),
   macroPointSize(16),

src/gui/gui.h

@@ -1118,6 +1118,7 @@ class FurnaceGUI {
   bool mobileEdit;
   bool willExport[DIV_MAX_CHIPS];
   int vgmExportVersion;
+  int vgmExportTrailingTicks;
   int drawHalt;
   int zsmExportTickRate;
   int macroPointSize;