Initial commit

Library/PackageCache/com.unity.2d.animation@3.2.6/Runtime/Triangle/TriangleSampler.cs

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+// -----------------------------------------------------------------------
+// <copyright file="TriangleSampler.cs">
+// Original Triangle code by Jonathan Richard Shewchuk, http://www.cs.cmu.edu/~quake/triangle.html
+// Triangle.NET code by Christian Woltering, http://triangle.codeplex.com/
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace UnityEngine.U2D.Animation.TriangleNet
+{
+    using System;
+    using System.Collections.Generic;
+    using Animation.TriangleNet.Topology;
+
+    /// <summary>
+    /// Used for triangle sampling in the <see cref="TriangleLocator"/> class.
+    /// </summary>
+    class TriangleSampler : IEnumerable<Triangle>
+    {
+        private const int RANDOM_SEED = 110503;
+
+        // Empirically chosen factor.
+        private const int samplefactor = 11;
+
+        private Random random;
+        private Mesh mesh;
+
+        // Number of random samples for point location (at least 1).
+        private int samples = 1;
+
+        // Number of triangles in mesh.
+        private int triangleCount = 0;
+
+        public TriangleSampler(Mesh mesh)
+            : this(mesh, new Random(RANDOM_SEED))
+        {
+        }
+
+        public TriangleSampler(Mesh mesh, Random random)
+        {
+            this.mesh = mesh;
+            this.random = random;
+        }
+
+        /// <summary>
+        /// Reset the sampler.
+        /// </summary>
+        public void Reset()
+        {
+            this.samples = 1;
+            this.triangleCount = 0;
+        }
+
+        /// <summary>
+        /// Update sampling parameters if mesh changed.
+        /// </summary>
+        public void Update()
+        {
+            int count = mesh.triangles.Count;
+
+            if (triangleCount != count)
+            {
+                triangleCount = count;
+
+                // The number of random samples taken is proportional to the cube root
+                // of the number of triangles in the mesh.  The next bit of code assumes
+                // that the number of triangles increases monotonically (or at least
+                // doesn't decrease enough to matter).
+                while (samplefactor * samples * samples * samples < count)
+                {
+                    samples++;
+                }
+            }
+        }
+
+        public IEnumerator<Triangle> GetEnumerator()
+        {
+            return mesh.triangles.Sample(samples, random).GetEnumerator();
+        }
+
+        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+    }
+}