hmd orient, vr ui

src/app.h

@@ -80,6 +80,9 @@ public:
     bool keys[256];
     bool redraw = true;
     bool animate = false;
+    glm::mat4 vr_rot{ 0 };
+    glm::mat4 vr_uirot{ 0 };
+    glm::vec2 cursor{ 0, 0 };
     glm::vec2 gesture_p0;
     glm::vec2 gesture_p1;
 #ifdef __ANDROID__