Esempio n. 1
0
        private static Sphere GetCircumsphere(Tetrahedron tetra)
        {
            var p = tetra.p;

            float[][] a = new float[][] {
                new float[] { p[1].x - p[0].x, p[1].y - p[0].y, p[1].z - p[0].z },
                new float[] { p[2].x - p[0].x, p[2].y - p[0].y, p[2].z - p[0].z },
                new float[] { p[3].x - p[0].x, p[3].y - p[0].y, p[3].z - p[0].z }
            };

            float[] b =
            {
                0.5f * (p[1].x * p[1].x - p[0].x * p[0].x + p[1].y * p[1].y - p[0].y * p[0].y + p[1].z * p[1].z - p[0].z * p[0].z),
                0.5f * (p[2].x * p[2].x - p[0].x * p[0].x + p[2].y * p[2].y - p[0].y * p[0].y + p[2].z * p[2].z - p[0].z * p[0].z),
                0.5f * (p[3].x * p[3].x - p[0].x * p[0].x + p[3].y * p[3].y - p[0].y * p[0].y + p[3].z * p[3].z - p[0].z * p[0].z)
            };

            float[] x = { 0f, 0f, 0f };

            var det = Gauss(a, b, ref x);

            if (det == 0)
            {
                return(new Sphere(Vector3.zero, -1));
            }
            else
            {
                var center = new Vector3(x[0], x[1], x[2]);
                return(new Sphere(center, Vector3.Distance(center, p[0])));
            }
        }
Esempio n. 2
0
        private static List <Triangle> GetDelaunayTriangles(List <Vector3> vertices)
        {
            var tetras = new HashSet <Tetrahedron>();

            Tetrahedron huge = GetHugeTetrahedron(vertices);

            tetras.Add(huge);

            foreach (var v in vertices)
            {
                var counter = new Counter <Tetrahedron>();
                var trash   = new List <Tetrahedron>();

                foreach (var t in tetras)
                {
                    var sphere = GetCircumsphere(t);
                    if (Vector3.Distance(sphere.center, v) < sphere.radius)
                    {
                        counter.Add(new Tetrahedron(v, t.p[0], t.p[1], t.p[2]));
                        counter.Add(new Tetrahedron(v, t.p[0], t.p[2], t.p[3]));
                        counter.Add(new Tetrahedron(v, t.p[0], t.p[1], t.p[3]));
                        counter.Add(new Tetrahedron(v, t.p[1], t.p[2], t.p[3]));
                        trash.Add(t);
                    }
                }
                tetras.RemoveWhere(t => trash.Contains(t));

                foreach (KeyValuePair <Tetrahedron, int> entry in counter)
                {
                    if (entry.Value == 1)
                    {
                        tetras.Add(entry.Key);
                    }
                }
            }

            tetras.RemoveWhere(t => huge.ShareVertex(t));

            var triangles = new HashSet <Triangle>();

            foreach (var t in tetras)
            {
                triangles.Add(new Triangle(t.p[0], t.p[1], t.p[2]));
                triangles.Add(new Triangle(t.p[0], t.p[2], t.p[3]));
                triangles.Add(new Triangle(t.p[0], t.p[1], t.p[3]));
                triangles.Add(new Triangle(t.p[1], t.p[2], t.p[3]));
            }
            return(triangles.ToList());
        }