add experimental menu

src/app_vr.cpp

@@ -1,6 +1,26 @@
 #include "pch.h"
 #include "app.h"
 
+#ifdef _WIN32
+bool win32_vr_start();
+void win32_vr_stop();
+#endif
+
+
+bool App::vr_start()
+{
+#ifdef _WIN32
+    return win32_vr_start();
+#endif
+}
+
+void App::vr_stop()
+{
+#ifdef _WIN32
+    win32_vr_stop();
+#endif
+}
+
 void App::vr_draw(const glm::mat4& proj, const glm::mat4& camera, const glm::mat4& pose)
 {
     //glm::mat4 ortho_proj = glm::ortho(0.f, box.z, 0.f, box.w, -1000.f, 1000.f);