public bool ContainsVertex(gVertex vertex)
{
gVertex maxVertex = vertices.OrderByDescending(v => v.DistanceTo(vertex)).First();
double maxDistance = vertex.DistanceTo(maxVertex) * 1.5;
gVertex v2 = gVertex.ByCoordinates(vertex.X + maxDistance, vertex.Y, vertex.Z);
gEdge ray = gEdge.ByStartVertexEndVertex(vertex, v2);
gVertex coincident = null;
int windNumber = 0;
foreach (gEdge edge in edges)
{
gBase intersection = ray.Intersection(edge);
if (edge.StartVertex.Y <= vertex.Y)
{
if (edge.EndVertex.Y > vertex.Y && intersection != null && intersection.GetType() == typeof(gVertex))
{
++windNumber;
}
}
else
{
if (edge.EndVertex.Y <= vertex.Y && intersection != null && intersection.GetType() == typeof(gVertex))
{
--windNumber;
}
}
}
//If intersections is odd, returns true, false otherwise
//return (intersections % 2 == 0) ? false : true;
return(windNumber != 0);
}
internal gPolygon AddVertex(gVertex v, gEdge intersectingEdge)
{
//Assumes that vertex v intersects one of polygons edges.
gPolygon newPolygon = (gPolygon)this.Clone();
// Assign the polygon Id to the new vertex.
v.polygonId = this.id;
// Getting the index of the intersecting edge's start vertex and
// inserting the new vertex at the following index.
int index = newPolygon.vertices.IndexOf(intersectingEdge.StartVertex);
newPolygon.vertices.Insert(index + 1, v);
// Rebuilding edges.
newPolygon.edges.Clear();
int verticesCount = newPolygon.vertices.Count;
for (var i = 0; i < verticesCount; i++)
{
int nextIndex = (i + 1) % verticesCount;
newPolygon.edges.Add(new gEdge(newPolygon.vertices[i], newPolygon.vertices[nextIndex]));
}
return(newPolygon);
}
public bool IsCoplanarTo(gEdge edge)
{
// http://mathworld.wolfram.com/Coplanar.html
gVector a = this.Direction;
gVector b = edge.Direction;
gVector c = gVector.ByTwoVertices(this.StartVertex, edge.StartVertex);
return(c.Dot(a.Cross(b)) == 0);
}
public double DistanceTo(gEdge edge)
{
// http://mathworld.wolfram.com/Point-LineDistance3-Dimensional.html
gVector v1 = gVector.ByTwoVertices(this, edge.StartVertex);
gVector v2 = gVector.ByTwoVertices(this, edge.EndVertex);
gVector numerator = v1.Cross(v2);
gVector denominator = gVector.ByTwoVertices(edge.EndVertex, edge.StartVertex);
return(numerator.Length / denominator.Length);
}
public bool Intersects(gEdge edge)
{
if (this.StartVertex.OnEdge(edge) || this.EndVertex.OnEdge(edge))
{
if (this.Direction.IsParallelTo(edge.Direction))
{
return(true);
}
}
return(this.Intersection(edge) != null);
}
//public Line AsLine()
//{
// return Line.ByStartPointEndPoint(StartVertex.AsPoint(), EndVertex.AsPoint());
//}
#region override methods
//TODO: Improve overriding equality methods as per http://www.loganfranken.com/blog/687/overriding-equals-in-c-part-1/
/// <summary>
/// Override of Equal Method
/// </summary>
/// <param name="obj"></param>
/// <returns></returns>
public override bool Equals(object obj)
{
if (obj == null || GetType() != obj.GetType())
{
return(false);
}
gEdge e = (gEdge)obj;
if (StartVertex.Equals(e.StartVertex) && EndVertex.Equals(e.EndVertex))
{
return(true);
}
if (StartVertex.Equals(e.EndVertex) && EndVertex.Equals(e.StartVertex))
{
return(true);
}
return(false);
}
public double DistanceTo(gEdge edge)
{
// http://mathworld.wolfram.com/Line-LineDistance.html
if (this.IsCoplanarTo(edge))
{
var distances = new double[4] {
StartVertex.DistanceTo(edge),
EndVertex.DistanceTo(edge),
edge.StartVertex.DistanceTo(this),
edge.EndVertex.DistanceTo(this)
};
return(distances.Min());
}
else
{
var a = this.Direction;
var b = edge.Direction;
var c = gVector.ByTwoVertices(this.StartVertex, edge.StartVertex);
gVector cross = a.Cross(b);
double numerator = c.Dot(cross);
double denominator = cross.Length;
return(Math.Abs(numerator) / Math.Abs(denominator));
}
}
public gBase Intersection(gEdge edge)
{
// http://mathworld.wolfram.com/Line-LineIntersection.html
if (!this.IsCoplanarTo(edge))
{
return(null);
}
if (edge.Contains(this.StartVertex))
{
return(StartVertex);
}
if (edge.Contains(this.EndVertex))
{
return(EndVertex);
}
var a = this.Direction;
var b = edge.Direction;
var c = gVector.ByTwoVertices(this.StartVertex, edge.StartVertex);
var cxb = c.Cross(b);
var axb = a.Cross(b);
var dot = cxb.Dot(axb);
// if dot == 0 it means that they are parallels
if (Threshold(dot, 0))
{
//Fully contains the test edge
if (edge.StartVertex.OnEdge(this) && edge.EndVertex.OnEdge(this))
{
return(edge);
}
else if (this.StartVertex.OnEdge(edge) || this.EndVertex.OnEdge(edge))
{
gVertex[] vertices = new gVertex[4]
{
this.StartVertex,
this.EndVertex,
edge.StartVertex,
edge.EndVertex
};
var sorted = vertices.OrderBy(v => v.Y).ThenBy(v => v.X).ThenBy(v => v.Z).ToList();
return(gEdge.ByStartVertexEndVertex(sorted[1], sorted[2]));
}
else
{
return(null);
}
}
double s = (dot) / Math.Pow(axb.Length, 2);
// s > 1, means that "intersection" vertex is not on either edge
// s == NaN means they are parallels so never intersect
if (s < 0 || s > 1 || Double.IsNaN(s))
{
return(null);
}
gVertex intersection = this.StartVertex.Translate(a.Scale(s));
if (intersection.Equals(edge.StartVertex))
{
return(edge.StartVertex);
}
if (intersection.Equals(edge.EndVertex))
{
return(edge.EndVertex);
}
if (!intersection.OnEdge(edge))
{
return(null);
}
return(intersection);
}
public bool OnEdge(gEdge edge)
{
return(this.OnEdge(edge.StartVertex, edge.EndVertex));
}