public static GJKwithEPA CreateInstance()
 {
     if (instance == null)
     {
         instance = new GJKwithEPA();
         return(instance);
     }
     else
     {
         return(null);
     }
 }
    private void Start()
    {
        switch (bType)
        {
        case broadphaseType.Dummy:
            broadphase = Dummy.CreateInstance();
            break;

        case broadphaseType.AABBTree:
            break;
        }

        switch (cType)
        {
        case collisionDetectionType.GJK:
            collisionDetection = GJKwithEPA.CreateInstance();
            break;

        case collisionDetectionType.SAT:
            break;
        }
    }