fix some threading issues

src/engine/engine.cpp

@@ -822,10 +822,6 @@ void DivEngine::runExportThread() {
   size_t curFadeOutSample=0;
   bool isFadingOut=false;
 
-  quitDispatch();
-  initDispatch(true);
-  renderSamples();
-
   switch (exportMode) {
     case DIV_EXPORT_MODE_ONE: {
       SNDFILE* sf;
@@ -838,9 +834,6 @@ void DivEngine::runExportThread() {
       sf=sfWrap.doOpen(exportPath.c_str(),SFM_WRITE,&si);
       if (sf==NULL) {
         logE("could not open file for writing! (%s)",sf_strerror(NULL));
-        quitDispatch();
-        initDispatch(false);
-        renderSamples();
         exporting=false;
         return;
       }
@@ -1153,9 +1146,6 @@ void DivEngine::runExportThread() {
     }
   }
 
-  quitDispatch();
-  initDispatch(false);
-  renderSamples();
   stopExport=false;
 }
 #else
@@ -1163,6 +1153,11 @@ void DivEngine::runExportThread() {
 }
 #endif
 
+bool DivEngine::shallSwitchCores() {
+  // TODO: detect whether we should
+  return true;
+}
+
 bool DivEngine::saveAudio(const char* path, int loops, DivAudioExportModes mode, double fadeOutTime) {
 #ifndef HAVE_SNDFILE
   logE("Furnace was not compiled with libsndfile. cannot export!");
@@ -1192,6 +1187,20 @@ bool DivEngine::saveAudio(const char* path, int loops, DivAudioExportModes mode,
   } else {
     remainingLoops=-1;
   }
+
+  if (shallSwitchCores()) {
+    bool isMutedBefore[DIV_MAX_CHANS];
+    memcpy(isMutedBefore,isMuted,DIV_MAX_CHANS*sizeof(bool));
+    quitDispatch();
+    initDispatch(true);
+    renderSamplesP();
+    for (int i=0; i<tchans; i++) {
+      if (isMutedBefore[i]) {
+        muteChannels(i,true);
+      }
+    }
+  }
+
   exportLoopCount=loops;
   exportThread=new std::thread(_runExportThread,this);
   return true;
@@ -1206,10 +1215,27 @@ void DivEngine::waitAudioFile() {
 
 bool DivEngine::haltAudioFile() {
   stopExport=true;
+  waitAudioFile();
   stop();
+  finishAudioFile();
   return true;
 }
 
+void DivEngine::finishAudioFile() {
+  if (shallSwitchCores()) {
+    bool isMutedBefore[DIV_MAX_CHANS];
+    memcpy(isMutedBefore,isMuted,DIV_MAX_CHANS*sizeof(bool));
+    quitDispatch();
+    initDispatch(false);
+    renderSamplesP();
+    for (int i=0; i<tchans; i++) {
+      if (isMutedBefore[i]) {
+        muteChannels(i,true);
+      }
+    }
+  }
+}
+
 void DivEngine::notifyInsChange(int ins) {
   BUSY_BEGIN;
   for (int i=0; i<song.systemLen; i++) {

src/engine/engine.h

@@ -497,6 +497,7 @@ class DivEngine {
   void playSub(bool preserveDrift, int goalRow=0);
   void runMidiClock(int totalCycles=1);
   void runMidiTime(int totalCycles=1);
+  bool shallSwitchCores();
 
   void testFunction();
 
@@ -614,6 +615,8 @@ class DivEngine {
     void waitAudioFile();
     // stop audio file export
     bool haltAudioFile();
+    // return back to playback cores if necessary
+    void finishAudioFile();
     // notify instrument parameter change
     void notifyInsChange(int ins);
     // notify wavetable change

src/gui/gui.cpp

@@ -5262,6 +5262,7 @@ bool FurnaceGUI::loop() {
         }
       }
       if (!e->isExporting()) {
+        e->finishAudioFile();
         ImGui::CloseCurrentPopup();
       }
       ImGui::EndPopup();