Merge pull request #406 from chuongmep/checkisonline

Add method point is on line

src/GShark.Test.XUnit/Geometry/Point3Tests.cs

@@ -1,4 +1,5 @@
-using FluentAssertions;
+using System.Security.Cryptography.X509Certificates;
+using FluentAssertions;
 using GShark.Geometry;
 using haxe.ds;
 using Xunit;
@@ -58,6 +59,25 @@ public void It_Checks_If_A_Point_Lies_On_A_Plane()
             pt.IsOnPlane(plane, 0.001).Should().BeTrue();
         }
 
+        [Fact]
+        public void It_Check_Point_Is_On_Line()
+        {
+            //Arrange
+            Point3 p1 = new Point3(0, 5, 0);
+            Point3 p2 = new Point3(0, 20, 0);
+            Point3 p3 = new Point3(0, 0, 0);
+            Line line1 = new Line(new Point3(0,0,0), new Point3(0,10,0));
+            // Act
+            bool isOnLine = p2.IsOnLine(line1);
+            bool isOnLine1 = p1.IsOnLine(line1);
+            bool isOnLine2 = p3.IsOnLine(line1);
+            // Assert
+            Assert.False(isOnLine);
+            Assert.True(isOnLine1);
+            Assert.True(isOnLine2);
+
+        }
+
         [Fact]
         public void It_Returns_The_Linear_Interpolation_Between_Two_Points()
         {

src/GShark/Geometry/Point3.cs

@@ -599,6 +599,17 @@ public bool IsOnPlane(Plane plane, double tolerance = GSharkMath.MaxTolerance)
         {
             return Math.Abs(Vector3.DotProduct(this - plane.Origin, plane.ZAxis)) < tolerance;
         }
+
+        /// <summary>
+        /// Test whether a point lies on a line.
+        /// </summary>
+        /// <param name="line">The line to test against.</param>
+        /// <param name="tolerance">Default is use 1e-6</param>
+        /// <returns>Returns true if point is on plane.</returns>
+        public bool IsOnLine(Line line, double tolerance = GSharkMath.MaxTolerance)
+        {
+            return line.ClosestPoint(this).DistanceTo(this) < tolerance;
+        }
 
         /// <summary>
         /// Tests whether a point is inside, outside, or coincident with a polygon.