GUI: prepare for more UX improvements

- add "temporary instrument" to DivEngine
- prepare for two things:
  - instrument preview on file picker (at least built-in one)
  - instrument selector for banks (#364)

src/engine/engine.cpp

@@ -739,6 +739,7 @@ String DivEngine::getWarnings() {
 }
 
 DivInstrument* DivEngine::getIns(int index, DivInstrumentType fallbackType) {
+  if (index==-2 && tempIns!=NULL) return tempIns;
   if (index<0 || index>=song.insLen) {
     switch (fallbackType) {
       case DIV_INS_OPLL:
@@ -1363,6 +1364,15 @@ int DivEngine::addInstrumentPtr(DivInstrument* which) {
   return song.insLen;
 }
 
+void DivEngine::loadTempIns(DivInstrument* which) {
+  BUSY_BEGIN;
+  if (tempIns==NULL) {
+    tempIns=new DivInstrument;
+  }
+  memcpy(tempIns,which,sizeof(DivInstrument));
+  BUSY_END;
+}
+
 void DivEngine::delInstrument(int index) {
   BUSY_BEGIN;
   saveLock.lock();

src/engine/engine.h

@@ -302,6 +302,7 @@ class DivEngine {
 
   public:
     DivSong song;
+    DivInstrument* tempIns;
     DivSystem sysOfChan[DIV_MAX_CHANS];
     int dispatchOfChan[DIV_MAX_CHANS];
     int dispatchChanOfChan[DIV_MAX_CHANS];
@@ -525,6 +526,9 @@ class DivEngine {
     // if the returned vector is empty then there was an error.
     std::vector<DivInstrument*> instrumentFromFile(const char* path);
 
+    // load temporary instrument
+    void loadTempIns(DivInstrument* which);
+
     // delete instrument
     void delInstrument(int index);
 
@@ -798,6 +802,7 @@ class DivEngine {
       metroAmp(0.0f),
       metroVol(1.0f),
       totalProcessed(0),
+      tempIns(NULL),
       oscBuf{NULL,NULL},
       oscSize(1),
       oscReadPos(0),

src/gui/gui.cpp

@@ -2419,7 +2419,7 @@ bool FurnaceGUI::loop() {
       }
     }
 
-    wantCaptureKeyboard=ImGui::GetIO().WantCaptureKeyboard;
+    wantCaptureKeyboard=ImGui::GetIO().WantTextInput;
     
     while (true) {
       midiLock.lock();