UnityEngine.Geometry.GetMidpointIndex C# (CSharp) Method

        private static int GetMidpointIndex(Dictionary<string, int> midpointIndices, List<Vector3> vertices, int i0, int i1)
        {
            var edgeKey = string.Format("{0}_{1}", Mathf.Min(i0, i1), Mathf.Max(i0, i1));

            var midpointIndex = -1;

            if (!midpointIndices.TryGetValue(edgeKey, out midpointIndex))
            {
                var v0 = vertices[i0];
                var v1 = vertices[i1];

                var midpoint = (v0 + v1) / 2f;

                if (vertices.Contains(midpoint))
                    midpointIndex = vertices.IndexOf(midpoint);
                else
                {
                    midpointIndex = vertices.Count;
                    vertices.Add(midpoint);
                    midpointIndices.Add(edgeKey, midpointIndex);
                }
            }

            return midpointIndex;
        }