/// <summary>
/// Triangulation algorithm of building segments, based on vertices collection
/// </summary>
/// <param name="vertices">Collection of all predefined vertices (points)</param>
/// <returns>Collection of non-intersecting segments which in total form a set of triangles</returns>
/// <remarks><see cref="ITriangulation.Triangulate(VertexCollection)"/> implementation</remarks>
public List <Edge> Triangulate(VertexCollection vertices)
{
Util.Check.NotNull(vertices, "Can't triangulate null collection");
var i = 0u;
foreach (var v in vertices)
{
v.Id = i++;
}
;
var vvertices = vertices.OrderBy(v => v.X).ThenBy(v => v.Y);
Vertices = vvertices.ToVertexCollection();
var result = new List <Edge>();
Debug.WriteLine($"Create Super Triangle:");
var superTriangle = GetSuperTriangle(vertices);
Debug.WriteLine($"{superTriangle}");
var triangulation = new HashSet <Triangle>
{
superTriangle
};
foreach (var point in vvertices)
{
var badTriangles = FindBadTriangles(point, triangulation);
var polygon = FindHoleBoundaries(badTriangles);
foreach (var triangle in badTriangles)
{
foreach (var vertex in triangle.Vertices)
{
vertex.AdjacentTriangles.Remove(triangle);
}
}
triangulation.RemoveWhere(triangle => badTriangles.Contains(triangle));
Debug.WriteLine("Start build new triangles");
Debug.WriteLine($"Current point: {point}");
var posibleEdges = polygon.Where(possibleEdge => possibleEdge.Start != point && possibleEdge.End != point).DistinctEdge().ToList();
foreach (var edge in posibleEdges)
{
Debug.WriteLine($"Edge for new triangle: {edge}");
if ((point.X == edge.Start.X && point.X == edge.End.X) ||
(point.Y == edge.Start.Y && point.Y == edge.End.Y))
{
Debug.WriteLine(new string('-', 20));
Debug.WriteLine("Something wrong");
continue;
}
var triangle = new Triangle(point, edge.Start, edge.End);
triangulation.Add(triangle);
}
}
triangulation.RemoveWhere(t => t.Vertices.Any(v => superTriangle.Vertices.Contains(v)));
Triangles = triangulation.ToList();
foreach (var triangle in triangulation)
{
triangle.Vertices.
ForEach(v => v.AdjacentTriangles.RemoveWhere(t => t.Vertices.Intersect(superTriangle.Vertices).Any()));
result.AddRange(triangle.Edges);
}
return(result.DistinctEdge().ToList());
}
