/// <summary>
/// Radian angle from a centre to another point
/// </summary>
/// <param name="centre"></param>
/// <param name="point"></param>
/// <returns name="rad">Radians</returns>
internal static double RadAngle(Point centre, Point point)
{
Vertex v1 = Vertex.ByCoordinates(centre.X, centre.Y, centre.Z);
Vertex v2 = Vertex.ByCoordinates(point.X, point.Y, point.Z);
return(Vertex.RadAngle(v1, v2));
}
/// <summary>
/// Determines if a Vertex is inside the gPolygon using Fast Winding Number method
/// </summary>
/// <param name="vertex"></param>
/// <returns></returns>
public bool ContainsVertex(Vertex vertex)
{
// http://geomalgorithms.com/a03-_inclusion.html
Vertex maxVertex = vertices.OrderByDescending(v => v.DistanceTo(vertex)).First();
double maxDistance = vertex.DistanceTo(maxVertex) * 1.5;
Vertex v2 = Vertex.ByCoordinates(vertex.X + maxDistance, vertex.Y, vertex.Z);
Edge ray = Edge.ByStartVertexEndVertex(vertex, v2);
int windNumber = 0;
foreach (Edge edge in edges)
{
if (vertex.OnEdge(edge))
{
return(true);
}
Vertex intersection = ray.Intersection(edge) as Vertex;
if (intersection is Vertex)
{
if (edge.StartVertex.Y <= vertex.Y)
{
if (edge.EndVertex.Y > vertex.Y)
{
if (IsLeft(edge, vertex) > 0)
{
++windNumber;
}
}
}
else
{
if (edge.EndVertex.Y < vertex.Y)
{
if (IsLeft(edge, vertex) < 0)
{
--windNumber;
}
}
}
}
}
// If windNumber is different from 0, vertex is in polygon
return(windNumber != 0);
}
public static Polygon ByCenterRadiusAndSides(Vertex center, double radius, int sides)
{
// TODO: create polygon by plane?
if (sides < 3)
{
throw new ArgumentOutOfRangeException("sides", "Any polygon must have at least 3 sides.");
}
List <Vertex> vertices = new List <Vertex>();
double angle = (Math.PI * 2) / sides;
for (var i = 0; i < sides; i++)
{
var vertex = Vertex.ByCoordinates(
(Math.Sin(i * angle) * radius) + center.X,
(Math.Cos(i * angle) * radius) + center.Y,
center.Z
);
vertices.Add(vertex);
}
return(Polygon.ByVertices(vertices));
}
public static Vertex ToVertex(this Point point)
{
return(Vertex.ByCoordinates(point.X, point.Y, point.Z));
}
public Vertex AsVertex()
{
return(Vertex.ByCoordinates(this.X, this.Y, this.Z));
}
