draw vr ui when vr thread starts on win

src/main.cpp

@@ -599,6 +599,10 @@ bool win32_vr_start()
         vive->on_button = std::bind(&App::vr_digital, App::I, std::placeholders::_1,
             std::placeholders::_2, std::placeholders::_3, std::placeholders::_4);
 
+        App::I->render_task([] {
+            App::I->vr_draw_ui();
+        });
+
         const float target_tick_rate = 90;
         auto t0 = GetTickCount64();
         float one_sec_timer = 0;