GUI: add option to select render backend

src/gui/gui.cpp

@@ -5488,10 +5488,32 @@ bool FurnaceGUI::init() {
   }
 #endif
 
+  int numDrivers=SDL_GetNumRenderDrivers();
+  if (numDrivers<0) {
+    logW("could not list render drivers! %s",SDL_GetError());
+  } else {
+    SDL_RendererInfo ri;
+    for (int i=0; i<numDrivers; i++) {
+      int r=SDL_GetRenderDriverInfo(i,&ri);
+      if (r!=0) continue;
+      availRenderDrivers.push_back(String(ri.name));
+    }
+  }
+
+  if (!settings.renderDriver.empty()) {
+    SDL_SetHint(SDL_HINT_RENDER_DRIVER,settings.renderDriver.c_str());
+  }
+
   sdlRend=SDL_CreateRenderer(sdlWin,-1,SDL_RENDERER_ACCELERATED|SDL_RENDERER_PRESENTVSYNC|SDL_RENDERER_TARGETTEXTURE);
 
   if (sdlRend==NULL) {
     lastError=fmt::sprintf("could not init renderer! %s",SDL_GetError());
+    if (!settings.renderDriver.empty()) {
+      settings.renderDriver="";
+      e->setConf("renderDriver","");
+      e->saveConf();
+      lastError=fmt::sprintf("\r\nthe render driver has been set to a safe value. please restart Furnace.");
+    }
     return false;
   }
 

src/gui/gui.h

@@ -1105,7 +1105,7 @@ class FurnaceGUI {
   std::vector<FurnaceGUISysDef> newSongSearchResults;
   std::deque<String> recentFile;
   std::vector<DivInstrumentType> makeInsTypeList;
-
+  std::vector<String> availRenderDrivers;
 
   bool quit, warnQuit, willCommit, edit, modified, displayError, displayExporting, vgmExportLoop, zsmExportLoop, vgmExportPatternHints;
   bool vgmExportDirectStream, displayInsTypeList;
@@ -1307,6 +1307,7 @@ class FurnaceGUI {
     String midiInDevice;
     String midiOutDevice;
     String c163Name;
+    String renderDriver;
     String initialSysName;
     String noteOffLabel;
     String noteRelLabel;
@@ -1443,6 +1444,7 @@ class FurnaceGUI {
       midiInDevice(""),
       midiOutDevice(""),
       c163Name(""),
+      renderDriver(""),
       initialSysName("Sega Genesis/Mega Drive"),
       noteOffLabel("OFF"),
       noteRelLabel("==="),

src/gui/settings.cpp

@@ -1207,6 +1207,18 @@ void FurnaceGUI::drawSettings() {
         ImVec2 settingsViewSize=ImGui::GetContentRegionAvail();
         settingsViewSize.y-=ImGui::GetFrameHeight()+ImGui::GetStyle().WindowPadding.y;
         if (ImGui::BeginChild("SettingsView",settingsViewSize)) {
+          if (ImGui::BeginCombo("Render driver",settings.renderDriver.empty()?"Automatic":settings.renderDriver.c_str())) {
+            if (ImGui::Selectable("Automatic",settings.renderDriver.empty())) {
+              settings.renderDriver="";
+            }
+            for (String& i: availRenderDrivers) {
+              if (ImGui::Selectable(i.c_str(),i==settings.renderDriver)) {
+                settings.renderDriver=i;
+              }
+            }
+            ImGui::EndCombo();
+          }
+
           bool dpiScaleAuto=(settings.dpiScale<0.5f);
           if (ImGui::Checkbox("Automatic UI scaling factor",&dpiScaleAuto)) {
             if (dpiScaleAuto) {
@@ -2447,6 +2459,7 @@ void FurnaceGUI::syncSettings() {
   settings.midiInDevice=e->getConfString("midiInDevice","");
   settings.midiOutDevice=e->getConfString("midiOutDevice","");
   settings.c163Name=e->getConfString("c163Name",DIV_C163_DEFAULT_NAME);
+  settings.renderDriver=e->getConfString("renderDriver","");
   settings.audioQuality=e->getConfInt("audioQuality",0);
   settings.audioBufSize=e->getConfInt("audioBufSize",1024);
   settings.audioRate=e->getConfInt("audioRate",44100);
@@ -2762,6 +2775,7 @@ void FurnaceGUI::commitSettings() {
   e->setConf("midiInDevice",settings.midiInDevice);
   e->setConf("midiOutDevice",settings.midiOutDevice);
   e->setConf("c163Name",settings.c163Name);
+  e->setConf("renderDriver",settings.renderDriver);
   e->setConf("audioQuality",settings.audioQuality);
   e->setConf("audioBufSize",settings.audioBufSize);
   e->setConf("audioRate",settings.audioRate);