Update examples (add interpolation example 10).

src/Triangle.Examples/Examples/Example1.cs

@@ -27,7 +27,7 @@ namespace TriangleNet.Examples
 
             if (print) SvgImage.Save(mesh, "example-1.svg", 500);
 
-            return true;
+            return mesh.Triangles.Count > 0;
         }
     }
 }

src/Triangle.Examples/Examples/Example10.cs

@@ -0,0 +1,125 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using TriangleNet.Geometry;
+using TriangleNet.Meshing;
+using TriangleNet.Meshing.Algorithm;
+using TriangleNet.Rendering.Text;
+using TriangleNet.Tools;
+
+namespace TriangleNet.Examples
+{
+    /// <summary>
+    /// Scattered data interpolation without USE_Z or USE_ATTRIBS.
+    /// </summary>
+    internal class Example10
+    {
+        // The function we are sampling.
+        private static readonly Func<Point, double> F = p => Math.Sin(p.X) * Math.Cos(p.Y);
+
+        public static bool Run(bool print = false)
+        {
+            // The input domain.
+            var r = new Rectangle(0d, 0d, 10d, 10d);
+
+            var mesh = GetScatteredDataMesh(r, out double[] data);
+            //var mesh = GetStructuredDataMesh(r, out double[] data);
+
+            if (print) SvgImage.Save(mesh, "example-10.svg", 500);
+
+            // The points to interpolate.
+            var xy = Generate.RandomPoints(50, r);
+
+            var xyData = InterpolateData((Mesh)mesh, data, xy);
+
+            double error = xy.Max(p => Math.Abs(xyData[p.ID] - F(p)));
+
+            // L2 error
+           // double error = Math.Sqrt(xy.Sum(p => Math.Pow(xyData[p.ID] - F(p), 2)));
+
+            return error < 0.5;
+        }
+
+        private static IMesh GetStructuredDataMesh(Rectangle domain, out double[] data)
+        {
+            var mesh = GenericMesher.StructuredMesh(domain, 20, 20);
+
+            mesh.Renumber();
+
+            // Generate function values for mesh points.
+            data = new double[mesh.Vertices.Count];
+
+            foreach (var item in mesh.Vertices)
+            {
+                data[item.ID] = F(item);
+            }
+
+            return mesh;
+        }
+
+        private static IMesh GetScatteredDataMesh(Rectangle domain, out double[] data)
+        {
+            var r = new Rectangle(domain);
+
+            double h = domain.Width / 20;
+
+            // Generate a rectangle boundary point set (20 points on each side).
+            var input = Generate.Rectangle(r, 0.5);
+
+            // Making sure we add some margin to the boundary.
+            h = -h / 2;
+            r.Resize(h, h);
+
+            // Add more input points (more sampling points, better interpolation).
+            input.Points.AddRange(Generate.RandomPoints(350, r));
+
+            var mesher = new GenericMesher(new Dwyer());
+
+            // Generate mesh.
+            var mesh = mesher.Triangulate(input.Points);
+
+            mesh.Renumber();
+
+            // Generate function values for mesh points.
+            data = new double[mesh.Vertices.Count];
+
+            foreach (var item in mesh.Vertices)
+            {
+                data[item.ID] = F(item);
+            }
+
+            return mesh;
+        }
+
+        private static double[] InterpolateData(Mesh mesh, double[] data, IEnumerable<Point> xy)
+        {
+            // The interpolated values.
+            var values = new double[xy.Count()];
+
+            var qtree = new TriangleQuadTree(mesh);
+
+            int i = 0;
+
+            foreach (var p in xy)
+            {
+                var tri = qtree.Query(p.X, p.Y);
+
+                // For easy access of the interpolated values.
+                p.ID = i;
+
+                if (tri == null)
+                {
+                    values[i] = float.NaN;
+                }
+                else
+                {
+                    values[i] = Interpolation.InterpolatePoint(tri, p, data);
+                }
+
+                i++;
+            }
+
+            return values;
+        }
+    }
+}

src/Triangle.Examples/Examples/Example2.cs

@@ -22,7 +22,7 @@
 
             if (print) SvgImage.Save(mesh, "example-2.svg", 500);
 
-            return true;
+            return mesh.Triangles.Count > 0;
         }
 
         public static IPolygon CreatePolygon(double h = 0.2)

src/Triangle.Examples/Examples/Example3.cs

@@ -19,7 +19,7 @@ namespace TriangleNet.Examples
 
             if (print) SvgImage.Save(mesh, "example-3.svg", 500);
 
-            return true;
+            return mesh.Triangles.Count > 0;
         }
 
         public static IMesh CreateMesh()

src/Triangle.Examples/Examples/Example4.cs

@@ -43,7 +43,7 @@ namespace TriangleNet.Examples
 
             if (print) SvgImage.Save(mesh, "example-4.svg", 500);
 
-            return true;
+            return mesh.Triangles.Count > 0;
         }
 
         public static IPolygon CreatePolygon()

src/Triangle.Examples/Examples/Example5.cs

@@ -25,7 +25,7 @@ namespace TriangleNet.Examples
 
             if (print) SvgImage.Save(mesh, "example-5-2.svg", 500, true, false);
 
-            return true;
+            return mesh.Triangles.Count > 0;
         }
 
         /// <summary>

src/Triangle.Examples/Examples/Example6.cs

@@ -4,6 +4,7 @@
     using TriangleNet;
     using TriangleNet.Geometry;
     using TriangleNet.Meshing.Iterators;
+    using TriangleNet.Rendering.Text;
     using TriangleNet.Tools;
     using TriangleNet.Topology;
 
@@ -12,14 +13,14 @@
     /// </summary>
     public static class Example6
     {
-        public static bool Run()
+        public static bool Run(bool print = true)
         {
             // Generate the input geometry.
             var polygon = new Polygon(8, true);
 
             // Two intersecting rectangles.
-            var A = Generate.Rectangle(0.0, 0.0, 4.0, 4.0, 1);
-            var B = Generate.Rectangle(1.0, 1.0, 4.0, 4.0, 2);
+            var A = Generate.Rectangle(0d, 0d, 4d, 4d, label: 1);
+            var B = Generate.Rectangle(1d, 1d, 4d, 4d, label: 2);
 
             polygon.Add(A);
             polygon.Add(B);
@@ -27,6 +28,8 @@
             // Generate mesh.
             var mesh = (Mesh)polygon.Triangulate();
 
+            if (print) SvgImage.Save(mesh, "example-6.svg", 500);
+
             // Find a seeding triangle (in this case, the point (2, 2) lies in
             // both rectangles).
             var seed = (new TriangleQuadTree(mesh)).Query(2.0, 2.0) as Triangle;
@@ -47,7 +50,7 @@
             // The xor of A and B.
             var xor = mesh.Triangles.Where(t => t.Label == 1 || t.Label == 2);
 
-            return true;
+            return intersection.Any() && difference.Any() && xor.Any();
         }
     }
 }

src/Triangle.Examples/Examples/Example7.cs

@@ -37,7 +37,7 @@ namespace TriangleNet.Examples
 
                 if (length > MAX_EDGE_LENGTH)
                 {
-                    Console.WriteLine("Something's wrong in here ...");
+                    return false;
                 }
             }
 

src/Triangle.Examples/Examples/Example8.cs

@@ -16,12 +16,10 @@ namespace TriangleNet.Examples
         {
             var mesh = (Mesh)Example3.CreateMesh();
 
-            FindAdjacencyMatrix(mesh);
-
-            return true;
+            return FindAdjacencyMatrix(mesh);
         }
 
-        private static void FindAdjacencyMatrix(Mesh mesh)
+        private static bool FindAdjacencyMatrix(Mesh mesh)
         {
             mesh.Renumber();
 
@@ -57,8 +55,10 @@ namespace TriangleNet.Examples
             // Column pointers should be exactly the same.
             if (!CompareArray(matrix1.ColumnPointers, matrix2.ColumnPointers))
             {
-                Console.WriteLine("Something's wrong in here ...");
+                return false;
             }
+
+            return true;
         }
 
         private static bool CompareArray(int[] a, int[] b)