public static XMVector Normalize(XMVector v)
        {
            XMVector result = XMVector2.Length(v);
            float    length = result.X;

            // Prevent divide by zero
            if (length > 0)
            {
                length = 1.0f / length;
            }

            result.X = v.X * length;
            result.Y = v.Y * length;
            result.Z = v.Z * length;
            result.W = v.W * length;

            return(result);
        }
        public static XMVector LinePointDistance(XMVector linePoint1, XMVector linePoint2, XMVector point)
        {
            //// Given a vector PointVector from LinePoint1 to Point and a vector
            //// LineVector from LinePoint1 to LinePoint2, the scaled distance
            //// PointProjectionScale from LinePoint1 to the perpendicular projection
            //// of PointVector onto the line is defined as:
            ////
            ////     PointProjectionScale = dot(PointVector, LineVector) / LengthSq(LineVector)

            XMVector pointVector = XMVector.Subtract(point, linePoint1);
            XMVector lineVector  = XMVector.Subtract(linePoint2, linePoint1);

            XMVector lengthSq = XMVector2.LengthSquare(lineVector);

            XMVector pointProjectionScale = XMVector2.Dot(pointVector, lineVector);

            pointProjectionScale = XMVector.Divide(pointProjectionScale, lengthSq);

            XMVector distanceVector = XMVector.Multiply(lineVector, pointProjectionScale);

            distanceVector = XMVector.Subtract(pointVector, distanceVector);

            return(XMVector2.Length(distanceVector));
        }