BEPUutilities.Toolbox.RayCastSphere C# (CSharp) Method

        public static bool RayCastSphere(ref Ray ray, ref Vector3 spherePosition, float radius, float maximumLength, out RayHit hit)
        {
            Vector3 normalizedDirection;
            float length = ray.Direction.Length();
            Vector3.Divide(ref ray.Direction, length, out normalizedDirection);
            maximumLength *= length;
            hit = new RayHit();
            Vector3 m;
            Vector3.Subtract(ref ray.Position, ref spherePosition, out m);
            float b = Vector3.Dot(m, normalizedDirection);
            float c = m.LengthSquared() - radius * radius;

            if (c > 0 && b > 0)
                return false;
            float discriminant = b * b - c;
            if (discriminant < 0)
                return false;

            hit.T = -b - (float)Math.Sqrt(discriminant);
            if (hit.T < 0)
                hit.T = 0;
            if (hit.T > maximumLength)
                return false;
            hit.T /= length;
            Vector3.Multiply(ref normalizedDirection, hit.T, out hit.Location);
            Vector3.Add(ref hit.Location, ref ray.Position, out hit.Location);
            Vector3.Subtract(ref hit.Location, ref spherePosition, out hit.Normal);
            hit.Normal.Normalize();
            return true;
        }