public static ShapeCollision TestCircleVsCircle
            (Circle circleA, Circle circleB, ShapeCollision into = null, bool flip = false)
        {
            Circle circle1 = flip ? circleB : circleA;
            Circle circle2 = flip ? circleA : circleB;

            //add both radii together to get the colliding distance
            float totalRadius = circle1.TransformedRadius + circle2.TransformedRadius;
            //find the distance between teh two circles
            float distanceSquared = (circle1.Position- circle2.Position).LengthSquared();

            if(distanceSquared < totalRadius * totalRadius)
            {
                if (into == null)
                {
                    into = new ShapeCollision();
                }
                else
                {
                    into.Reset();
                }

                float difference = totalRadius - (float)Math.Sqrt(distanceSquared);

                into.Tested = circle1;
                into.TestedAgainst = circle2;

                Vector2 unitVector = circle1.Position - circle2.Position;
                unitVector.Normalize();

                into.UnitVectorX = unitVector.X;
                into.UnitVectorY = unitVector.Y;

                into.SeperationX = unitVector.X * difference;
                into.SeperationY = unitVector.Y * difference;

                return into;
            }

            return null;
        }