Added flag for fullscreen toggle.

src/xenia/app/xenia_main.cc

@@ -42,6 +42,7 @@ DEFINE_string(gpu, "any", "Graphics system. Use: [any, gl4, vulkan, null]");
 DEFINE_string(hid, "any", "Input system. Use: [any, nop, winkey, xinput]");
 
 DEFINE_string(target, "", "Specifies the target .xex or .iso to execute.");
+DEFINE_bool(fullscreen, false, "Toggles fullscreen");
 
 namespace xe {
 namespace app {
@@ -191,6 +192,9 @@ int xenia_main(const std::vector<std::wstring>& args) {
     }
   }
 
+  // Toggles fullscreen
+  if (FLAGS_fullscreen) emulator_window->ToggleFullscreen();
+
   if (!path.empty()) {
     // Normalize the path and make absolute.
     std::wstring abs_path = xe::to_absolute_path(path);