GUI: make the new button work

src/engine/engine.cpp

@@ -1428,6 +1428,22 @@ void DivEngine::renderSamples() {
   }
 }
 
+void DivEngine::createNew() {
+  DivSystem sys=song.system;
+  quitDispatch();
+  isBusy.lock();
+  song.unload();
+  song=DivSong();
+  song.system=sys;
+  chans=getChannelCount(song.system);
+  renderSamples();
+  isBusy.unlock();
+  initDispatch();
+  isBusy.lock();
+  reset();
+  isBusy.unlock();
+}
+
 void DivEngine::changeSystem(DivSystem which) {
   quitDispatch();
   isBusy.lock();

src/engine/engine.h

@@ -130,6 +130,8 @@ class DivEngine {
     void nextBuf(float** in, float** out, int inChans, int outChans, unsigned int size);
     DivInstrument* getIns(int index);
     DivWavetable* getWave(int index);
+    // start fresh
+    void createNew();
     // load a .dmf.
     bool load(unsigned char* f, size_t length);
     // save as .dmf.

src/gui/gui.cpp

@@ -2237,10 +2237,11 @@ bool FurnaceGUI::loop() {
 
     ImGui::BeginMainMenuBar();
     if (ImGui::BeginMenu("file")) {
-      ImGui::MenuItem("new");
+      if (ImGui::MenuItem("new")) {
+        e->createNew();
+      }
       if (ImGui::MenuItem("open...")) {
         openFileDialog(GUI_FILE_OPEN);
-        
       }
       ImGui::Separator();
       ImGui::MenuItem("save");