public gEdge(gVertex start, gVertex end)
{
StartVertex = start;
EndVertex = end;
Length = StartVertex.DistanceTo(EndVertex);
Direction = gVector.ByTwoVertices(StartVertex, EndVertex);
}
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 static gVector ByTwoVertices(gVertex start, gVertex end)
{
var x = end.X - start.X;
var y = end.Y - start.Y;
var z = end.Z - start.Z;
var length = Math.Sqrt(Math.Pow(x, 2) + Math.Pow(y, 2) + Math.Pow(z, 2));
return(new gVector(x, y, z, length));
}
public static gPolygon ByVertices(List <gVertex> vertices, bool isExternal)
{
gPolygon polygon = new gPolygon(-1, isExternal);
polygon.vertices = vertices;
int vertexCount = vertices.Count;
for (var j = 0; j < vertexCount; j++)
{
int next_index = (j + 1) % vertexCount;
gVertex vertex = vertices[j];
gVertex next_vertex = vertices[next_index];
polygon.edges.Add(new gEdge(vertex, next_vertex));
}
return(polygon);
}
/// <summary>
/// Method to return the other end vertex of the gEdge
/// </summary>
/// <param name="vertex"></param>
/// <returns></returns>
public gVertex GetVertexPair(gVertex vertex)
{
return((StartVertex.Equals(vertex)) ? EndVertex : StartVertex);
}
/// <summary>
/// gEdge constructor by line
/// </summary>
/// <param name="line">line</param>
/// <returns name="edge">edge</returns>
//public static gEdge ByLine(Line line)
//{
// gVertex start = gVertex.ByCoordinates(line.StartPoint.X, line.StartPoint.Y, line.StartPoint.Z);
// gVertex end = gVertex.ByCoordinates(line.EndPoint.X, line.EndPoint.Y, line.EndPoint.Z);
// return new gEdge(start, end);
//}
#endregion
/// <summary>
/// Method to check if vertex belongs to edge
/// </summary>
/// <param name="vertex"></param>
/// <returns></returns>
public bool Contains(gVertex vertex)
{
return(StartVertex.Equals(vertex) || EndVertex.Equals(vertex));
}
/// <summary>
/// gEdge constructor by start and end vertices
/// </summary>
/// <param name="start">Start vertex</param>
/// <param name="end">End gVertex</param>
/// <returns name="edge">edge</returns>
public static gEdge ByStartVertexEndVertex(gVertex start, gVertex end)
{
return(new gEdge(start, end));
}
public double DistanceTo(gVertex vertex)
{
return(vertex.DistanceTo(this));
}
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);
}
internal void AddVertex(gVertex vertex)
{
vertex.polygonId = this.id;
vertices.Add(vertex);
}