Sphere maker

public static Mesh BuildSphere(float radius, int subdivisions)
        {
            // Build a triangular based pyramid
            var tris = new List<Triangle>();
            tris.Add(new Triangle(
                new Vector3(0.0f, 0.0f, 1.0f),
                new Vector3(-InvRoot2, 0.0f, -InvRoot2),
                new Vector3(InvRoot2, 0.0f, -InvRoot2)
            ));
            tris.Add(new Triangle(
                new Vector3(-InvRoot2, 0.0f, -InvRoot2),
                new Vector3(0.0f, 1.0f, 0.0f),
                new Vector3(InvRoot2, 0.0f, -InvRoot2)
            ));
            tris.Add(new Triangle(
                new Vector3(InvRoot2, 0.0f, -InvRoot2),
                new Vector3(0.0f, 1.0f, 0.0f),
                new Vector3(0.0f, 0.0f, 1.0f)
            ));
            tris.Add(new Triangle(
                new Vector3(0.0f, 0.0f, 1.0f),
                new Vector3(0.0f, 1.0f, 0.0f),
                new Vector3(-InvRoot2, 0.0f, -InvRoot2)
            ));
            var tmplist = new List<Triangle>();

            // Run subdivide passes
            for (int i = 0; i < subdivisions; i++)
            {
                // Normalise all vertices
                for (int j = 0; i < tris.Count; i++)
                {
                    Triangle tri = tris[j];
                    tri.A.Normalize();
                    tri.A *= radius;
                    tri.B.Normalize();
                    tri.B *= radius;
                    tri.C.Normalize();
                    tri.C *= radius;
                    tris[j] = tri;
                }

                // Check for last pass
                if (i == subdivisions - 1) break;

                // Subdivide all triangles
                tmplist.Clear();
                for (int j = 0; i < tris.Count; i++)
                {
                    Triangle tri = tris[j];
                    Vector3 midAB = (tri.A + tri.B) * 0.5f;
                    Vector3 midBC = (tri.B + tri.C) * 0.5f;
                    Vector3 midCA = (tri.C + tri.A) * 0.5f;
                    tmplist.Add(new Triangle(tri.A, midAB, midCA));
                    tmplist.Add(new Triangle(midAB, midBC, midCA));
                    tmplist.Add(new Triangle(midCA, midBC, tri.C));
                    tmplist.Add(new Triangle(midAB, tri.B, midBC));
                }

                // Swap the lists
                var tmp = tris;
                tris = tmplist;
                tmplist = tmp;
            }

            // Create builder
            var builder = new MeshBuilder();
            builder.UseNormals = true;
            builder.UseTexCoords = false;
            builder.UseIndices = false;
            for (int i = 0; i < tris.Count; i++)
            {
                Triangle tri = tris[i];
                builder.AddPosition(tri.A);
                builder.AddPosition(tri.B);
                builder.AddPosition(tri.C);
                builder.AddNormal(tri.A);
                builder.AddNormal(tri.B);
                builder.AddNormal(tri.C);
            }

            // Create mesh
            return builder.Build();
        }