protected override void UpdateParameter() { var posOfPrevious = PolarCoordinate.FromOrthogonal(Input.MouseLeft.Previous - Parameters.RotationCenter.ToVector2()); var posOfCurrent = PolarCoordinate.FromOrthogonal(Input.MouseLeft.Current - Parameters.RotationCenter.ToVector2()); Parameters.RotationAngle = posOfCurrent.DifferenceOfAngle(posOfPrevious); }