GUI: add option to disable threaded input

src/gui/gui.cpp

@@ -2479,7 +2479,13 @@ void FurnaceGUI::processPoint(SDL_Event& ev) {
 }
 
 bool FurnaceGUI::loop() {
-  SDL_SetEventFilter(_processEvent,this);
+  bool doThreadedInput=!settings.noThreadedInput;
+  if (doThreadedInput) {
+    logD("key input: event filter");
+    SDL_SetEventFilter(_processEvent,this);
+  } else {
+    logD("key input: main thread");
+  }
 
   while (!quit) {
     SDL_Event ev;
@@ -2495,6 +2501,7 @@ bool FurnaceGUI::loop() {
       WAKE_UP;
       ImGui_ImplSDL2_ProcessEvent(&ev);
       processPoint(ev);
+      if (!doThreadedInput) processEvent(&ev);
       switch (ev.type) {
         case SDL_MOUSEMOTION: {
           int motionX=ev.motion.x;

src/gui/gui.h

@@ -1091,6 +1091,7 @@ class FurnaceGUI {
     int blankIns;
     int dragMovesSelection;
     int unsignedDetune;
+    int noThreadedInput;
     unsigned int maxUndoSteps;
     String mainFontPath;
     String patFontPath;
@@ -1193,6 +1194,7 @@ class FurnaceGUI {
       blankIns(0),
       dragMovesSelection(1),
       unsignedDetune(0),
+      noThreadedInput(0),
       maxUndoSteps(100),
       mainFontPath(""),
       patFontPath(""),

src/gui/settings.cpp

@@ -460,6 +460,14 @@ void FurnaceGUI::drawSettings() {
             ImGui::SetTooltip("saves power by lowering the frame rate to 2fps when idle.\nmay cause issues under Mesa drivers!");
           }
 
+          bool noThreadedInputB=settings.noThreadedInput;
+          if (ImGui::Checkbox("Disable threaded input (restart after changing!)",&noThreadedInputB)) {
+            settings.noThreadedInput=noThreadedInputB;
+          }
+          if (ImGui::IsItemHovered()) {
+            ImGui::SetTooltip("threaded input processes key presses for note preview on a separate thread (on supported platforms), which reduces latency.\nhowever, crashes have been reported when threaded input is on. enable this option if that is the case.");
+          }
+
           bool blankInsB=settings.blankIns;
           if (ImGui::Checkbox("New instruments are blank",&blankInsB)) {
             settings.blankIns=blankInsB;
@@ -2055,6 +2063,7 @@ void FurnaceGUI::syncSettings() {
   settings.blankIns=e->getConfInt("blankIns",0);
   settings.dragMovesSelection=e->getConfInt("dragMovesSelection",2);
   settings.unsignedDetune=e->getConfInt("unsignedDetune",0);
+  settings.noThreadedInput=e->getConfInt("noThreadedInput",0);
 
   clampSetting(settings.mainFontSize,2,96);
   clampSetting(settings.patFontSize,2,96);
@@ -2141,6 +2150,7 @@ void FurnaceGUI::syncSettings() {
   clampSetting(settings.blankIns,0,1);
   clampSetting(settings.dragMovesSelection,0,2);
   clampSetting(settings.unsignedDetune,0,1);
+  clampSetting(settings.noThreadedInput,0,1);
 
   settings.initialSys=e->decodeSysDesc(e->getConfString("initialSys",""));
   if (settings.initialSys.size()<4) {
@@ -2276,6 +2286,7 @@ void FurnaceGUI::commitSettings() {
   e->setConf("blankIns",settings.blankIns);
   e->setConf("dragMovesSelection",settings.dragMovesSelection);
   e->setConf("unsignedDetune",settings.unsignedDetune);
+  e->setConf("noThreadedInput",settings.noThreadedInput);
 
   // colors
   for (int i=0; i<GUI_COLOR_MAX; i++) {