Verification to use the correct camera and minor code improvements
The incorrect (or null) camera can be fetched for games which use more than one camera giving null or invalid positions, this change search for the correct camera before converting the position to a screen point.
I also renamed
gameObject in GameObjectToAltUnityObject to
unityObject because it hides UnityEngine.Component.gameObject and moved the local variable
position to a method variable. (It wasn't being used outside the method's scope)