Added demonstration bowyer watson walkthrough algorithm with a simple example triangle

DelaunayTriangulation/ViewModels/MainWindowViewModel.cs

@@ -38,6 +38,7 @@ public partial class MainWindowViewModel : ViewModelBase
     [ObservableProperty] private bool _doNearestTriangle = false;
     [ObservableProperty] private bool _doDelaunayLib = false;
     [ObservableProperty] private bool _doBowyerWatson = true;
+    [ObservableProperty] private bool _doDemonstration = false;
 
     [ObservableProperty] private int? _generationDelay = 20;
     private CancellationTokenSource? _genCts;
@@ -160,8 +161,6 @@ public partial class MainWindowViewModel : ViewModelBase
                 i--;
                 retry++;
             }
-
-            ;
         }
 
         l.Sort(Geometries.PointComparer.Instance);
@@ -566,6 +565,149 @@ public partial class MainWindowViewModel : ViewModelBase
         }
     }
 
+    async Task DemonstrationDelaunay(CancellationToken ct)
+    {
+        async Task RunCancellationSafe(Action toRun)
+        {
+            toRun();
+            await DelayAsync(ct);
+            ct.ThrowIfCancellationRequested();
+        }
+
+        // first point
+        var c = new Geometries.Point(Width / 2, Height / 2);
+        await RunCancellationSafe(() => Points.Add(c));
+
+        // build super triangle
+        var t1 = new Geometries.Point(c.X, c.Y - 100);
+        var t2 = new Geometries.Point(c.X - 100, c.Y + 75);
+        var t3 = new Geometries.Point(c.X + 100, c.Y + 75);
+
+        await RunCancellationSafe(() => Points.Add(t1));
+        await RunCancellationSafe(() => Points.Add(t2));
+        await RunCancellationSafe(() => Points.Add(t3));
+
+        // combine Points
+        var e1 = new Geometries.Edge(t1.X, t1.Y, t2.X, t2.Y);
+        var e2 = new Geometries.Edge(t1.X, t1.Y, t3.X, t3.Y);
+        var e3 = new Geometries.Edge(t2.X, t2.Y, t3.X, t3.Y);
+        var e4 = new Geometries.Edge(t1.X, t1.Y, c.X, c.Y);
+        var e5 = new Geometries.Edge(t2.X, t2.Y, c.X, c.Y);
+        var e6 = new Geometries.Edge(t3.X, t3.Y, c.X, c.Y);
+
+        await RunCancellationSafe(() => Edges.Add(e1));
+        await RunCancellationSafe(() => Edges.Add(e2));
+        await RunCancellationSafe(() => Edges.Add(e3));
+        await RunCancellationSafe(() => Edges.Add(e4));
+        await RunCancellationSafe(() => Edges.Add(e5));
+        await RunCancellationSafe(() => Edges.Add(e6));
+
+        // show circumcircles to ensure delaunay criteria
+        var c1 = new Geometries.Circle(t1, t2, c);
+        var c2 = new Geometries.Circle(t2, t3, c);
+        var c3 = new Geometries.Circle(t1, t3, c);
+
+        await RunCancellationSafe(() => Circles.Add(c1));
+        await RunCancellationSafe(() => Circles.Add(c2));
+        await RunCancellationSafe(() => Circles.Add(c3));
+
+        // add extra point which breaks delaunay criteria
+        var t4 = new Geometries.Point(c.X - 50, c.Y + 35);
+        await RunCancellationSafe(() => Points.Add(t4));
+
+        // Fix triangulation
+        await RunCancellationSafe(() => Circles.Remove(c1));
+        await RunCancellationSafe(() => Circles.Remove(c2));
+
+        await RunCancellationSafe(() => Edges.Remove(e1));
+        await RunCancellationSafe(() => Edges.Remove(e3));
+        await RunCancellationSafe(() => Edges.Remove(e5));
+
+        // add new edges
+        e5 = new Geometries.Edge(t2.X, t2.Y, t4.X, t4.Y);
+        var e7 = new Geometries.Edge(t1.X, t1.Y, t4.X, t4.Y);
+        var e8 = new Geometries.Edge(t3.X, t3.Y, t4.X, t4.Y);
+        var e9 = new Geometries.Edge(c.X, c.Y, t4.X, t4.Y);
+
+        await RunCancellationSafe(() => Edges.Add(e1));
+        await RunCancellationSafe(() => Edges.Add(e3));
+        await RunCancellationSafe(() => Edges.Add(e5));
+        await RunCancellationSafe(() => Edges.Add(e7));
+        await RunCancellationSafe(() => Edges.Add(e8));
+        await RunCancellationSafe(() => Edges.Add(e9));
+
+        c1 = new Geometries.Circle(t1, t2, t4);
+        c2 = new Geometries.Circle(t2, t4, t3);
+        var c4 = new Geometries.Circle(t1, t4, c);
+        var c5 = new Geometries.Circle(t4, t3, c);
+
+        await RunCancellationSafe(() => Circles.Add(c1));
+        await RunCancellationSafe(() => Circles.Add(c2));
+        await RunCancellationSafe(() => Circles.Add(c4));
+        await RunCancellationSafe(() => Circles.Add(c5));
+
+        // add another point
+        var t5 = new Geometries.Point(c.X + 50, c.Y + 45);
+        await RunCancellationSafe(() => Points.Add(t5));
+
+        await RunCancellationSafe(() => Circles.Remove(c2));
+        await RunCancellationSafe(() => Circles.Remove(c3));
+        await RunCancellationSafe(() => Circles.Remove(c5));
+
+        await RunCancellationSafe(() => Edges.Remove(e3));
+        await RunCancellationSafe(() => Edges.Remove(e8));
+        await RunCancellationSafe(() => Edges.Remove(e6));
+        await RunCancellationSafe(() => Edges.Remove(e2));
+
+        e6 = new Geometries.Edge(c.X, c.Y, t5.X, t5.Y);
+        e8 = new Geometries.Edge(t2.X, t2.Y, t5.X, t5.Y);
+        var e10 = new Geometries.Edge(t5.X, t5.Y, t3.X, t3.Y);
+        var e11 = new Geometries.Edge(t5.X, t5.Y, t4.X, t4.Y);
+        var e12 = new Geometries.Edge(t5.X, t5.Y, t1.X, t1.Y);
+
+        await RunCancellationSafe(() => Edges.Add(e3));
+        await RunCancellationSafe(() => Edges.Add(e2));
+        await RunCancellationSafe(() => Edges.Add(e6));
+        await RunCancellationSafe(() => Edges.Add(e8));
+        await RunCancellationSafe(() => Edges.Add(e10));
+        await RunCancellationSafe(() => Edges.Add(e11));
+        await RunCancellationSafe(() => Edges.Add(e12));
+
+        c2 = new Geometries.Circle(t2, t5, t3);
+        c3 = new Geometries.Circle(t1, t5, t3);
+        c5 = new Geometries.Circle(c, t4, t5);
+        var c6 = new Geometries.Circle(t2, t4, t5);
+        var c7 = new Geometries.Circle(t1, c, t5);
+
+        await RunCancellationSafe(() => Circles.Add(c2));
+        await RunCancellationSafe(() => Circles.Add(c3));
+        await RunCancellationSafe(() => Circles.Add(c5));
+        await RunCancellationSafe(() => Circles.Add(c6));
+        await RunCancellationSafe(() => Circles.Add(c7));
+
+        // remove super triangle
+        await RunCancellationSafe(() => Circles.Remove(c1));
+        await RunCancellationSafe(() => Circles.Remove(c2));
+        await RunCancellationSafe(() => Circles.Remove(c3));
+        await RunCancellationSafe(() => Circles.Remove(c4));
+        await RunCancellationSafe(() => Circles.Remove(c6));
+        await RunCancellationSafe(() => Circles.Remove(c7));
+
+        await RunCancellationSafe(() => Edges.Remove(e1));
+        await RunCancellationSafe(() => Edges.Remove(e2));
+        await RunCancellationSafe(() => Edges.Remove(e3));
+        await RunCancellationSafe(() => Edges.Remove(e4));
+        await RunCancellationSafe(() => Edges.Remove(e5));
+        await RunCancellationSafe(() => Edges.Remove(e7));
+        await RunCancellationSafe(() => Edges.Remove(e8));
+        await RunCancellationSafe(() => Edges.Remove(e10));
+        await RunCancellationSafe(() => Edges.Remove(e12));
+
+        await RunCancellationSafe(() => Points.Remove(t1));
+        await RunCancellationSafe(() => Points.Remove(t2));
+        await RunCancellationSafe(() => Points.Remove(t3));
+    }
+
     public void CancelGeneration() => _genCts?.CancelAsync();
 
     private Task DelayAsync(CancellationToken ct) =>
@@ -595,12 +737,14 @@ public partial class MainWindowViewModel : ViewModelBase
 
         IsGenerationRunning = true;
 
-        await GenerateRandomPoints(PointCount ?? 20, ct);
+        if(!DoDemonstration) await GenerateRandomPoints(PointCount ?? 20, ct);
+
         if(DoConnectPoints) await ConnectPoints(ct);
         else if(DoConnectPointsV2) await ConnectPointsV2(ct);
         else if(DoNearestTriangle) await Triangulate(ct);
         else if(DoDelaunayLib) await DelaunayTriangulateAsync(ct);
         else if(DoBowyerWatson) await BowyerWatson(ct);
+        else if (DoDemonstration) await DemonstrationDelaunay(ct);
 
         IsGenerationRunning = false;
     }

DelaunayTriangulation/Views/MainWindow.axaml

@@ -118,7 +118,7 @@
                                         </Grid>
                                         <Grid ColumnDefinitions="1*, 1*">
                                             <RadioButton GroupName="Algorithm" HorizontalAlignment="Left" Content="Delaunay (Delaunator)" IsChecked="{Binding DoDelaunayLib}" Foreground="{DynamicResource B.Text}" Margin="10,0"/>
-                                            <!-- <RadioButton Grid.Column="1" GroupName="Algorithm" HorizontalAlignment="Left" Content="Delaunay (Delaunator)" IsChecked="{Binding DoDelaunayLib}" Foreground="{DynamicResource B.Text}" Margin="10,0"/> -->
+                                            <RadioButton Grid.Column="1" GroupName="Algorithm" HorizontalAlignment="Left" Content="Demonstration" IsChecked="{Binding DoDemonstration}" Foreground="{DynamicResource B.Text}" Margin="10,0"/>
                                         </Grid>
                                     </StackPanel>
                                 </Border>