Improve contour FindPointInPolygon() reliability (2).

2022-02-23 12:42:54 +01:00
parent bc955bb740
commit 2e83d7ee5e
3 changed files with 76 additions and 4 deletions
@@ -0,0 +1,41 @@
+using NUnit.Framework;
+using TriangleNet.Geometry;
+using TriangleNet.Tools;
+
+namespace TriangleNet.Tests.Tools
+{
+    public class IntersectionHelperTest
+    {
+        [Test]
+        public void TestIsPointOnSegment()
+        {
+            var a = new Vertex(1.0, 1.0);
+            var b = new Vertex(2.0, 2.0);
+
+            // Test point = segment start point.
+            Assert.IsTrue(IntersectionHelper.IsPointOnSegment(a, b, new Vertex(1.0, 1.0)));
+
+            // Test point = segment end point.
+            Assert.IsTrue(IntersectionHelper.IsPointOnSegment(a, b, new Vertex(2.0, 2.0)));
+
+            // Test point on segment.
+            Assert.IsTrue(IntersectionHelper.IsPointOnSegment(a, b, new Vertex(1.5, 1.5)));
+
+            // Test point collinear, but not on segment.
+            Assert.IsFalse(IntersectionHelper.IsPointOnSegment(a, b, new Vertex(0.0, 0.0)));
+            Assert.IsFalse(IntersectionHelper.IsPointOnSegment(a, b, new Vertex(3.0, 3.0)));
+
+            // Test point not on segment.
+            Assert.IsFalse(IntersectionHelper.IsPointOnSegment(a, b, new Vertex(1.5, 0.5)));
+
+            double eps = 1e-12;
+
+            // Test point collinear near endpoint, but not on segment.
+            Assert.IsFalse(IntersectionHelper.IsPointOnSegment(a, b, new Vertex(2.0 + eps, 2.0 + eps)));
+            Assert.IsFalse(IntersectionHelper.IsPointOnSegment(a, b, new Vertex(2.0 - eps, 2.0 + eps)));
+
+            // Test point collinear near endpoint on segment.
+            Assert.IsTrue(IntersectionHelper.IsPointOnSegment(a, b, new Vertex(2.0 - eps, 2.0 - eps)));
+        }
+    }
+}