Update

Assets/D.A. Assets/DA-Shared/ThirdParty/SVGMeshUnity/Internals/Cdt2d/DelaunayRefine.cs

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+/*
+MIT License
+
+Copyright (c) 2018 Yoshihiro Shindo
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+
+namespace DA_Assets.SVGMeshUnity.Internals.Cdt2d
+{
+    public class DelaunayRefine
+    {
+        public WorkBufferPool WorkBufferPool;
+        
+        //Assume edges are sorted lexicographically
+        public void RefineTriangles(Triangles triangles)
+        {
+            var stack = WorkBufferPool.Get<Int2>();
+
+            var points = triangles.Vertices;
+            var numPoints = points.Count;
+            var stars = triangles.Stars;
+            for (var a = 0; a < numPoints; ++a)
+            {
+                var star = stars[a];
+                var starData = star.Data;
+                var sl = star.UsedSize;
+                for (var j = 0; j < sl; ++j)
+                {
+                    var s = starData[j];
+                    var b = s.y;
+
+                    //If order is not consistent, then skip edge
+                    if (b < a)
+                    {
+                        continue;
+                    }
+
+                    //Check if edge is constrained
+                    if (triangles.IsConstraint(a, b))
+                    {
+                        continue;
+                    }
+
+                    //Find opposite edge
+                    var x = s.x;
+                    var y = -1;
+                    for (var k = 0; k < sl; ++k)
+                    {
+                        if (starData[k].x == b)
+                        {
+                            y = starData[k].y;
+                            break;
+                        }
+                    }
+
+                    //If this is a boundary edge, don't flip it
+                    if (y < 0)
+                    {
+                        continue;
+                    }
+
+                    //If edge is in circle, flip it
+                    if (Robust.InSphere(points[a], points[b], points[x], points[y]) < 0f)
+                    {
+                        var v = new Int2(a, b);
+                        stack.Push(ref v);
+                    }
+                }
+            }
+
+            while (stack.UsedSize > 0)
+            {
+                var v = stack.Pop();
+                var a = v.x;
+                var b = v.y;
+
+                //Find opposite pairs
+                var x = -1;
+                var y = -1;
+                var star = stars[a];
+                var starData = star.Data;
+                var sl = star.UsedSize;
+                for (var i = 0; i < sl; ++i)
+                {
+                    var s = starData[i].x;
+                    var t = starData[i].y;
+                    if (s == b)
+                    {
+                        y = t;
+                    }
+                    else if (t == b)
+                    {
+                        x = s;
+                    }
+                }
+
+                //If x/y are both valid then skip edge
+                if (x < 0 || y < 0)
+                {
+                    continue;
+                }
+
+                //If edge is now delaunay, then don't flip it
+                if (Robust.InSphere(points[a], points[b], points[x], points[y]) >= 0f)
+                {
+                    continue;
+                }
+
+                //Flip the edge
+                triangles.Flip(a, b);
+
+                //Test flipping neighboring edges
+                TestFlip(points, triangles, stack, x, a, y);
+                TestFlip(points, triangles, stack, a, y, x);
+                TestFlip(points, triangles, stack, y, b, x);
+                TestFlip(points, triangles, stack, b, x, y);
+            }
+
+            WorkBufferPool.Release(ref stack);
+        }
+        
+        private void TestFlip(List<Vector3> points, Triangles triangles, WorkBuffer<Int2> stack, int a, int b, int x)
+        {
+            var y = triangles.Opposite(a, b);
+
+            //Test boundary edge
+            if (y < 0)
+            {
+                return;
+            }
+
+            //Swap edge if order flipped
+            if (b < a)
+            {
+                var tmp = a;
+                a = b;
+                b = tmp;
+                tmp = x;
+                x = y;
+                y = tmp;
+            }
+
+            //Test if edge is constrained
+            if (triangles.IsConstraint(a, b))
+            {
+                return;
+            }
+
+            //Test if edge is delaunay
+            if (Robust.InSphere(points[a], points[b], points[x], points[y]) < 0f)
+            {
+                var v = new Int2(a, b);
+                stack.Push(ref v);
+            }
+        }
+    }
+}