/// <summary>
 /// Protected constructor
 /// </summary>
 /// <param name="mSceneMgr">A reference to the scene manager</param>
 /// <param name="characterStat">A reference to a character stat</param>
 protected HMD(SceneManager mSceneMgr, RenderWindow mWindow, CharacterStats characterStat)
 {
     this.mWindow        = mWindow;
     this.mSceneMgr      = mSceneMgr;
     this.characterStats = characterStat;
 }