add undo to instrument editor (check for diffs on the current DivInstrument in insEdit, record them in a stack)

src/gui/debugWindow.cpp

@@ -605,7 +605,7 @@ void FurnaceGUI::drawDebug() {
     }
     if (ImGui::TreeNode("Recent Files")) {
       ImGui::Text("Items: %d - Max: %d",(int)recentFile.size(),settings.maxRecentFile);
-      ImGui::Text("readPos: %d - writePos: %d",(int)recentFile.readPos,(int)recentFile.writePos);
+      ImGui::Text("readPos: %d - writePos: %d",(int)recentFile.readPos,(int)recentFile.writePos());
       ImGui::Indent();
       for (size_t i=0; i<recentFile.size(); i++) {
         ImGui::Text("%d: %s",(int)i,recentFile[i].c_str());

src/gui/doAction.cpp

@@ -73,6 +73,8 @@ void FurnaceGUI::doAction(int what) {
     case GUI_ACTION_UNDO:
       if (curWindow==GUI_WINDOW_SAMPLE_EDIT) {
         doUndoSample();
+      } else if (curWindow==GUI_WINDOW_INS_EDIT) {
+        doUndoInstrument();
       } else {
         doUndo();
       }
@@ -80,6 +82,8 @@ void FurnaceGUI::doAction(int what) {
     case GUI_ACTION_REDO:
       if (curWindow==GUI_WINDOW_SAMPLE_EDIT) {
         doRedoSample();
+      } else if (curWindow==GUI_WINDOW_INS_EDIT) {
+        doRedoInstrument();
       } else {
         doRedo();
       }

src/gui/gui.cpp

@@ -8310,6 +8310,7 @@ FurnaceGUI::FurnaceGUI():
   localeRequiresChineseTrad(false),
   localeRequiresKorean(false),
   prevInsData(NULL),
+  cachedCurInsPtr(NULL),
   pendingLayoutImport(NULL),
   pendingLayoutImportLen(0),
   pendingLayoutImportStep(0),

src/gui/gui.h

@@ -2256,6 +2256,8 @@ class FurnaceGUI {
   std::vector<ImWchar> localeExtraRanges;
 
   DivInstrument* prevInsData;
+  DivInstrument cachedCurIns;
+  DivInstrument* cachedCurInsPtr;
 
   unsigned char* pendingLayoutImport;
   size_t pendingLayoutImportLen;
@@ -2922,6 +2924,9 @@ class FurnaceGUI {
   void doUndoSample();
   void doRedoSample();
 
+  void doUndoInstrument();
+  void doRedoInstrument();
+
   void play(int row=0);
   void setOrder(unsigned char order, bool forced=false);
   void stop();

src/gui/insEdit.cpp

@@ -5250,6 +5250,7 @@ void FurnaceGUI::drawInsEdit() {
     ImGui::SetNextWindowSizeConstraints(ImVec2(440.0f*dpiScale,400.0f*dpiScale),ImVec2(canvasW,canvasH));
   }
   if (ImGui::Begin("Instrument Editor",&insEditOpen,globalWinFlags|(settings.allowEditDocking?0:ImGuiWindowFlags_NoDocking),_("Instrument Editor"))) {
+    DivInstrument* ins=nullptr;
     if (curIns==-2) {
       ImGui::SetCursorPosY(ImGui::GetCursorPosY()+(ImGui::GetContentRegionAvail().y-ImGui::GetFrameHeightWithSpacing()+ImGui::GetStyle().ItemSpacing.y)*0.5f);
       CENTER_TEXT(_("waiting..."));
@@ -5277,6 +5278,7 @@ void FurnaceGUI::drawInsEdit() {
                 curIns=i;
                 wavePreviewInit=true;
                 updateFMPreview=true;
+                ins = e->song.ins[curIns];
               }
             }
             ImGui::EndCombo();
@@ -5299,7 +5301,7 @@ void FurnaceGUI::drawInsEdit() {
         ImGui::EndTable();
       }
     } else {
-      DivInstrument* ins=e->song.ins[curIns];
+      ins=e->song.ins[curIns];
       if (updateFMPreview) {
         renderFMPreview(ins);
         updateFMPreview=false;
@@ -7738,7 +7740,51 @@ void FurnaceGUI::drawInsEdit() {
       
       ImGui::EndPopup();
     }
+    
+    if (ins) {
+      bool insChanged = ins != cachedCurInsPtr;
+      bool delayDiff = ImGui::IsMouseDown(ImGuiMouseButton_Left) || ImGui::IsMouseDown(ImGuiMouseButton_Right) || ImGui::GetIO().WantCaptureKeyboard;
+
+      // check against the last cached to see if diff -- note that modifications to instruments happen outside
+      // drawInsEdit (e.g. cursor inputs are processed and can directly modify macro data)
+      if (!insChanged && !delayDiff) {
+        ins->recordUndoStepIfChanged(e->processTime, &cachedCurIns);
+      }
+
+      if (insChanged || !delayDiff) {
+        cachedCurIns = *ins;
+      }
+
+      cachedCurInsPtr = ins;
+    } else {
+      cachedCurInsPtr = nullptr;
+    }
   }
+  
   if (ImGui::IsWindowFocused(ImGuiFocusedFlags_ChildWindows)) curWindow=GUI_WINDOW_INS_EDIT;
   ImGui::End();
 }
+
+void FurnaceGUI::doUndoInstrument() {
+  if (!insEditOpen) return;
+  if (curIns<0 || curIns>=(int)e->song.ins.size()) return;
+  DivInstrument* ins=e->song.ins[curIns];
+  // is locking the engine necessary? copied from doUndoSample
+  e->lockEngine([this,ins]() {
+    ins->undo();
+    cachedCurInsPtr=ins;
+    cachedCurIns=*ins;
+  });
+}
+
+void FurnaceGUI::doRedoInstrument() {
+  if (!insEditOpen) return;
+  if (curIns<0 || curIns>=(int)e->song.ins.size()) return;
+  DivInstrument* ins=e->song.ins[curIns];
+  // is locking the engine necessary? copied from doRedoSample
+  e->lockEngine([this,ins]() {
+    ins->redo();
+    cachedCurInsPtr=ins;
+    cachedCurIns=*ins;
+  });
+}