Ano-sys
426 lines
13 KiB
C#
426 lines
13 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Collections.ObjectModel;
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using System.ComponentModel;
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using System.Globalization;
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using System.Linq;
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using System.Threading;
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using System.Threading.Tasks;
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using Avalonia.Media;
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using Avalonia.Rendering.Composition.Animations;
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using CommunityToolkit.Mvvm.ComponentModel;
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using CommunityToolkit.Mvvm.Input;
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using DelaunatorSharp;
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using DelauneyTriangulation.Models;
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using DelauneyTriangulation.Views;
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namespace DelauneyTriangulation.ViewModels;
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public partial class MainWindowViewModel : ViewModelBase
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{
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public MainWindow? View { get; set; } = null;
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[ObservableProperty] private int? _pointCount = 20;
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[ObservableProperty] private int? _minPointDistance = 5;
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[ObservableProperty] private double _panX;
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[ObservableProperty] private double _panY;
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[ObservableProperty] private double _zoom = 1.0;
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[ObservableProperty] private bool _pointsVisible = true;
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[ObservableProperty] private bool _edgesVisible = true;
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[ObservableProperty] private bool _circlesVisible = true;
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[ObservableProperty] private bool _voronoiVisible = true;
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[ObservableProperty] private bool _trianglesVisible = true;
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[ObservableProperty] private int? _generationDelay = 20;
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private CancellationTokenSource? _genCts;
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public double Width { get; set; } = 1280;
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public double Height { get; set; } = 720;
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private double LeftOffset => Width / 4;
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private double TopOffset => Height - 50;
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public ObservableCollection<Geometries.Point> Points { get; set; } = new();
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public ObservableCollection<Geometries.Edge> Edges { get; } = new();
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public ObservableCollection<Geometries.Circle> Circles { get; } = new();
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public ObservableCollection<Geometries.Edge> VoronoiDiagram { get; } = new();
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public ObservableCollection<Geometries.Triangle> Triangles { get; } = new();
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public IAsyncRelayCommand GenerateCommand { get; }
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// gets distance of a and b edge to calc hypotenuse aka dist of two points
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double PointDistance(Geometries.Point p1, Geometries.Point p2) =>
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Math.Sqrt(Math.Pow(p1.X - p2.X, 2) + Math.Pow(p1.Y - p2.Y, 2));
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static bool Almost(double a, double b, double eps = 1e-9) => Math.Abs(a - b) <= eps;
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bool IsPointInCircumcircle(Geometries.Triangle t, Geometries.Point p)
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{
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var a = new Geometries.Point(t.X.X, t.X.Y);
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var b = new Geometries.Point(t.Y.X, t.Y.Y);
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var c = new Geometries.Point(t.Z.X, t.Z.Y);
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var circ = new Geometries.Circle(a, b, c);
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var d = PointDistance(new(circ.X, circ.Y), p);
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return d <= circ.R + 1e-9;
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}
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static bool UsesVertex(Geometries.Triangle t, Geometries.Point v)
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{
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bool isV(Avalonia.Point q) => Math.Abs(q.X - v.X) <= 1e-9 && Math.Abs(q.Y - v.Y) <= 1e-9;
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return isV(t.X) || isV(t.Y) || isV(t.Z);
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}
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(Geometries.Point A, Geometries.Point B, Geometries.Point C) BuildSuperTriangle()
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{
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var minX = Points.Min(p => p.X);
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var minY = Points.Min(p => p.Y);
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var maxX = Points.Max(p => p.X);
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var maxY = Points.Max(p => p.Y);
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var dx = maxX - minX;
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var dy = maxY - minY;
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var delta = Math.Max(dx, dy);
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var cx = (minX + maxX) * 0.5;
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var cy = (minY + maxY) * 0.5;
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var A = new Geometries.Point(cx - 2 * delta, cy - delta * 3);
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var B = new Geometries.Point(cx, cy + 3 * delta);
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var C = new Geometries.Point(cx + 2 * delta, cy - delta * 3);
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return (A, B, C);
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}
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async Task GenerateRandomPoints(int count, CancellationToken ct)
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{
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bool CheckAdd(Geometries.Point p1, IList<Geometries.Point> p) =>
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!p.Any(x => PointDistance(p1, x) <= MinPointDistance);
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Points.Clear();
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var rand = new Random();
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var rgb = (byte)(255 - PointCount);
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const byte a = 255;
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var color = new Color(rgb, rgb, rgb, a);
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List<Geometries.Point> l = new();
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int retry = 0;
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for (var i = 0; i < PointCount; i++)
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{
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ct.ThrowIfCancellationRequested();
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if (retry == 10) break;
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var x = rand.NextDouble() * (Width - LeftOffset) + LeftOffset;
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var y = rand.NextDouble() * (Height - TopOffset * 2) + TopOffset;
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var p = new Geometries.Point(x, y);
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if (CheckAdd(p, l))
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{
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p.Color = color;
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rgb++;
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color = new Color(rgb, rgb, rgb, a);
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l.Add(p);
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retry = 0;
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}
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else
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{
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i--;
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retry++;
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}
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;
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}
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l.Sort(Geometries.PointComparer.Instance);
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foreach (var p in l)
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{
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ct.ThrowIfCancellationRequested();
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Points.Add(p);
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await DelayAsync(ct);
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}
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}
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void ConnectPoint(Geometries.Point p1, Geometries.Point p2) =>
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Edges.Add(new Geometries.Edge(p1.X, p1.Y, p2.X, p2.Y));
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async Task ConnectPoints(CancellationToken ct)
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{
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if (Points.Count == 0) return;
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Edges.Clear();
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var toConnect = Points.ToList();
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var p1 = toConnect[0];
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while (toConnect.Count > 0)
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{
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ct.ThrowIfCancellationRequested();
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var p2 = toConnect.MinBy(x => PointDistance(p1, x));
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if (p2 is null) continue;
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ConnectPoint(p1, p2);
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toConnect.Remove(p1);
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p1 = p2;
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await DelayAsync(ct);
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}
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}
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void AddTriangle(Geometries.Point p1, Geometries.Point p2, Geometries.Point p3) => Triangles.Add(new(p1, p2, p3));
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async Task Triangulate(CancellationToken ct)
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{
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Triangles.Clear();
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if (Points.Count < 3) return;
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var toTriangulate = Points.ToList();
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var p1 = toTriangulate[0];
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var p2 = toTriangulate.Where(x => !ReferenceEquals(x, p1)).MinBy(x => PointDistance(p1, x));
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if (p2 is null) return;
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static double TwiceArea(Geometries.Point a, Geometries.Point b, Geometries.Point c) =>
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Math.Abs((b.X - a.X) * (c.Y - a.Y) - (b.Y - a.Y) * (c.X - a.X));
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while (toTriangulate.Count >= 3)
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{
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ct.ThrowIfCancellationRequested();
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var candidates = toTriangulate.Where(x => !ReferenceEquals(x, p1) && !ReferenceEquals(x, p2));
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Geometries.Point? p3 = null;
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foreach (var c in candidates.OrderBy(x => PointDistance(p1, x) + PointDistance(p2, x)))
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{
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if (TwiceArea(p1, p2, c) > 1e-6) p3 = c;
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break;
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}
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if (p3 is null) break;
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AddTriangle(p1, p2, p3);
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toTriangulate.Remove(p1);
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p1 = p2;
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p2 = p3;
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await DelayAsync(ct);
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}
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}
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List<Geometries.Edge> ExtractTriangleEdges(Geometries.Triangle t)
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{
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var e1 = new Geometries.Edge(t.X.X, t.X.Y, t.Y.X, t.Y.Y);
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var e2 = new Geometries.Edge(t.Y.X, t.Y.Y, t.Z.X, t.Z.Y);
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var e3 = new Geometries.Edge(t.Z.X, t.Z.Y, t.X.X, t.X.Y);
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return [e1, e2, e3];
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}
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static string CanonKey(Geometries.Edge e)
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{
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var abFirst = (e.X1 < e.X2) || (Almost(e.X1, e.X2) && e.Y1 <= e.Y2);
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var ax = abFirst ? e.X1 : e.X2;
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var ay = abFirst ? e.Y1 : e.Y2;
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var bx = abFirst ? e.X2 : e.X1;
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var by = abFirst ? e.Y2 : e.Y1;
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static double Q(double v) => Math.Round(v, 9, MidpointRounding.AwayFromZero);
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return $"{Q(ax)},{Q(ay)}|{Q(bx)},{Q(by)}";
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}
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void DrawCircles(IEnumerable<Geometries.Triangle> triangles, Geometries.Point superA, Geometries.Point superB,
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Geometries.Point superC)
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{
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Circles.Clear();
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foreach (var t in triangles)
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{
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if (UsesVertex(t, superA) || UsesVertex(t, superB) || UsesVertex(t, superC)) continue;
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try
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{
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var a = new Geometries.Point(t.X.X, t.X.Y);
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var b = new Geometries.Point(t.Y.X, t.Y.Y);
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var c = new Geometries.Point(t.Z.X, t.Z.Y);
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var cc = new Geometries.Circle(a, b, c);
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if (double.IsFinite(cc.X) && double.IsFinite(cc.Y) && double.IsFinite(cc.R) && cc.R > 0)
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Circles.Add(cc);
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}
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catch (ArgumentException)
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{
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}
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}
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}
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async Task BowyerWatson(CancellationToken ct)
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{
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Triangles.Clear();
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if (Points.Count < 3) return;
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var (sa, sb, sc) = BuildSuperTriangle();
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Triangles.Add(new Geometries.Triangle(sa, sb, sc));
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await DelayAsync(ct);
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foreach (var p in Points)
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{
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ct.ThrowIfCancellationRequested();
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var bad = new List<Geometries.Triangle>();
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foreach (var t in Triangles)
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{
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try
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{
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if (IsPointInCircumcircle(t, p)) bad.Add(t);
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}
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catch (ArgumentException)
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{
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// kollinear -> explicit ignore
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}
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}
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DrawCircles(bad, sa, sb, sc);
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await DelayAsync(ct);
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var edgeCount = new Dictionary<string, Geometries.Edge>();
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var counter = new Dictionary<string, int>();
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foreach (var bt in bad)
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{
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foreach (var e in ExtractTriangleEdges(bt))
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{
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string key = CanonKey(e);
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if (!edgeCount.ContainsKey(key)) edgeCount[key] = e;
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counter.TryGetValue(key, out int c);
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counter[key] = c + 1;
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}
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}
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var polygon = new List<Geometries.Edge>();
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foreach (var kv in counter)
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if (kv.Value == 1)
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polygon.Add(edgeCount[kv.Key]);
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// remove bad triangles form triangulation
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foreach (var bt in bad) Triangles.Remove(bt);
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// re-triangulate the polygonal hole
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foreach (var e in polygon)
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{
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var a = new Geometries.Point(e.X1, e.Y1);
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var b = new Geometries.Point(e.X2, e.Y2);
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Triangles.Add(new Geometries.Triangle(a, b, p));
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await DelayAsync(ct);
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}
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}
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// remove triangles containing super triangle vertex
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var toRemove = new List<Geometries.Triangle>();
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foreach (var t in Triangles)
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{
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if (UsesVertex(t, sa) || UsesVertex(t, sb) || UsesVertex(t, sc)) toRemove.Add(t);
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}
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foreach (var t in toRemove) Triangles.Remove(t);
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DrawCircles(Triangles, sa, sb, sc);
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await DelayAsync(ct);
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}
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async Task DelaunayTriangulateAsync(CancellationToken ct)
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{
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Triangles.Clear();
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Edges.Clear();
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if (Points.Count < 3) return;
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var pts = Points.Select(p => (DelaunatorSharp.IPoint)new DelaunatorSharp.Point(p.X, p.Y)).ToArray();
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var d = new Delaunator(pts);
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// Delaunay Triangle Extraction
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for (int i = 0; i < d.Triangles.Length; i += 3)
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{
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ct.ThrowIfCancellationRequested();
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int i0 = d.Triangles[i];
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int i1 = d.Triangles[i + 1];
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int i2 = d.Triangles[i + 2];
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var p0 = Points[i0];
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var p1 = Points[i1];
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var p2 = Points[i2];
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Triangles.Add(new Geometries.Triangle(p0, p1, p2));
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await DelayAsync(ct);
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}
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// Konvex Hull Extraction
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var hullPoints = d.GetHullPoints();
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var first = hullPoints.First();
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var last = hullPoints.Last();
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var p1h = hullPoints[0];
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for (int h = 1; h < d.Hull.Length; h++)
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{
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var p2h = hullPoints[h];
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Edges.Add(new Geometries.Edge(p1h.X, p1h.Y, p2h.X, p2h.Y));
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p1h = p2h;
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await DelayAsync(ct);
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}
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Edges.Add(new Geometries.Edge(first.X, first.Y, last.X, last.Y));
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// Voronoi Diagram Extraction
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foreach (var cell in d.GetVoronoiCells())
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{
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ct.ThrowIfCancellationRequested();
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var f = cell.Points[0];
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for (int i = 1; i < cell.Points.Length; i++)
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{
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var s = cell.Points[i];
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VoronoiDiagram.Add(new Geometries.Edge(f.X, f.Y, s.X, s.Y));
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Circles.Add(new Geometries.Circle(f.X, f.Y,
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Points.Min(x => PointDistance(new Geometries.Point(f.X, f.Y), x))));
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f = s;
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await DelayAsync(ct);
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}
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}
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}
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private Task DelayAsync(CancellationToken ct) =>
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GenerationDelay > 0 ? Task.Delay(GenerationDelay ?? 0, ct) : Task.CompletedTask;
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async Task RunGenerateAsync()
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{
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_genCts?.CancelAsync();
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_genCts = new CancellationTokenSource();
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try
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{
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await Generate(_genCts.Token);
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}
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catch (OperationCanceledException)
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{
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}
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}
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private async Task Generate(CancellationToken ct)
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{
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Points.Clear();
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Edges.Clear();
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Circles.Clear();
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Triangles.Clear();
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VoronoiDiagram.Clear();
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await GenerateRandomPoints(PointCount ?? 20, ct);
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// await ConnectPoints(ct);
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// await Triangulate(ct);
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// await DelaunayTriangulateAsync(ct);
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await BowyerWatson(ct);
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}
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private bool CanGenerate() => true;
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public MainWindowViewModel()
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{
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GenerateCommand = new AsyncRelayCommand(RunGenerateAsync, CanGenerate);
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}
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} |