internal static bool DoesIntersect(Line line, DSPoint point)
{
Edge edge = Edge.ByStartVertexEndVertex(Points.ToVertex(line.StartPoint), Points.ToVertex(line.EndPoint));
Vertex vertex = Points.ToVertex(point);
return(vertex.OnEdge(edge));
}
internal Polygon AddVertex(Vertex vertex, Edge intersectinEdge)
{
//Assumes that vertex v intersects one of _polygonsDict Edges.
Polygon newPolygon = (Polygon)this.Clone();
// Assign the polygon Id to the new vertex.
vertex.Parent = this;
// Getting the index of the intersecting edge's start vertex and
// inserting the new vertex at the following index.
int index = newPolygon.vertices.IndexOf(intersectinEdge.StartVertex);
newPolygon.vertices.Insert(index + 1, vertex);
// 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(Edge.ByStartVertexEndVertex(newPolygon.vertices[i], newPolygon.vertices[nextIndex]));
}
return(newPolygon);
}
public Geometry Intersection(Edge edge)
{
// If no coplanar, cannot intersect
if (!edge.IsCoplanarTo(this.Origin, this.Direction))
{
return(null);
}
// Intersection can be an Edge or null
if (this.Direction.IsParallelTo(edge.Direction))
{
bool containsStart = this.Contains(edge.StartVertex);
bool containsEnd = this.Contains(edge.EndVertex);
if (!containsStart && !containsEnd)
{
return(null);
}
else if (containsStart)
{
return(Edge.ByStartVertexEndVertex(edge.StartVertex, this.Origin));
}
else
{
return(Edge.ByStartVertexEndVertex(this.Origin, edge.EndVertex));
}
}
// No coincident nor same extremes
var b = this.Direction;
var a = edge.Direction;
var c = Vector.ByTwoVertices(edge.StartVertex, this.Origin);
var cxb = c.Cross(b);
var axb = a.Cross(b);
var dot = cxb.Dot(axb);
double t = (dot) / Math.Pow(axb.Length, 2);
if (t < 0 && !t.AlmostEqualTo(0))
{
return(null);
}
if (t > 1 && !t.AlmostEqualTo(1))
{
return(null);
}
var intersection = edge.StartVertex.Translate(edge.Direction.Scale(t));
return(this.Contains(intersection) ? intersection : null);
}
private Edge DiagonalByVertexIndex(int start, int end)
{
var vertexCount = this.Vertices.Count;
if (start < 0 || start > vertexCount - 1)
{
throw new ArgumentOutOfRangeException("start", start, "Out of range");
}
if (end < 0 || end > vertexCount - 1)
{
throw new ArgumentOutOfRangeException("end", end, "Out of range");
}
return(Edge.ByStartVertexEndVertex(this.Vertices[start], this.Vertices[end]));
}
internal Polygon(List <Vertex> vertices, bool _isExternal = false) : base()
{
isBoundary = _isExternal;
int vertexCount = vertices.Count;
for (var j = 0; j < vertexCount; j++)
{
int next_index = (j + 1) % vertexCount;
Vertex vertex = vertices[j];
Vertex next_vertex = vertices[next_index];
var edge = Edge.ByStartVertexEndVertex(vertex, next_vertex);
vertex.Parent = this;
edge.Parent = this;
this.Vertices.Add(vertex);
this.Edges.Add(edge);
}
}
/// <summary>
/// Creates a new Graph by a set of lines.
/// </summary>
/// <param name="lines">Lines</param>
/// <returns name="baseGraph">Base Graph</returns>
public static BaseGraph ByLines(List <Line> lines)
{
if (lines == null)
{
throw new NullReferenceException("lines");
}
BaseGraph g = new BaseGraph()
{
graph = new Graphical.Graphs.Graph()
};
foreach (Line line in lines)
{
Vertex start = Geometry.Points.ToVertex(line.StartPoint);
Vertex end = Geometry.Points.ToVertex(line.EndPoint);
g.graph.AddEdge(Edge.ByStartVertexEndVertex(start, end));
}
return(g);
}
internal static bool DoesIntersect(Line line1, Line line2)
{
Edge edge1 = Edge.ByStartVertexEndVertex(Points.ToVertex(line1.StartPoint), Points.ToVertex(line1.EndPoint));
Edge edge2 = Edge.ByStartVertexEndVertex(Points.ToVertex(line2.StartPoint), Points.ToVertex(line2.EndPoint));
if (edge1.Intersects(edge2))
{
if (edge2.StartVertex.OnEdge(edge1))
{
return(false);
}
if (edge2.EndVertex.OnEdge(edge1))
{
return(false);
}
return(true);
}
else
{
return(false);
}
}
internal static Edge ToEdge(this Line line)
{
return(Edge.ByStartVertexEndVertex(line.StartPoint.ToVertex(), line.EndPoint.ToVertex()));
}
public Geometry Intersection(Edge other)
{
// http://mathworld.wolfram.com/Line-LineIntersection.html
if (!this.BoundingBox.Intersects(other.BoundingBox))
{
return(null);
}
if (!this.IsCoplanarTo(other))
{
return(null);
}
if (this.Equals(other))
{
return(this);
} // Issues if same polygon id???
var a = this.Direction;
var b = other.Direction;
if (a.IsParallelTo(b))
{
// Fully contains the test edge
if (other.StartVertex.OnEdge(this) && other.EndVertex.OnEdge(this))
{
return(other);
}
// Is fully contained by test edge
else if (this.StartVertex.OnEdge(other) && this.EndVertex.OnEdge(other))
{
return(this);
}
// Not fully inclusive but overlapping
else if (this.StartVertex.OnEdge(other) || this.EndVertex.OnEdge(other))
{
Vertex[] vertices = new Vertex[4]
{
this.StartVertex,
this.EndVertex,
other.StartVertex,
other.EndVertex
};
var sorted = vertices.OrderBy(v => v.Y).ThenBy(v => v.X).ThenBy(v => v.Z).ToList();
return(Edge.ByStartVertexEndVertex(sorted[1], sorted[2]));
}
// Not intersecting
else
{
return(null);
}
}
// No parallels but intersecting on one of the extreme Vertices
if (other.Contains(this.StartVertex))
{
return(this.StartVertex);
}
else if (other.Contains(this.EndVertex))
{
return(this.EndVertex);
}
// No coincident nor same extremes
var c = Vector.ByTwoVertices(this.StartVertex, other.StartVertex);
var cxb = c.Cross(b);
var axb = a.Cross(b);
var dot = cxb.Dot(axb);
// If dot == 0 it means that other edge contains at least a vertex from this edge
// and they are parallel or perpendicular. Cannot be parallel as that was tested before.
// It might also mean they don't intersect but the would if extending the projections
double s = (dot) / Math.Pow(axb.Length, 2);
if (s.AlmostEqualTo(0))
{
if (this.StartVertex.OnEdge(other))
{
return(this.StartVertex);
}
else if (this.EndVertex.OnEdge(other))
{
return(this.EndVertex);
}
else if (other.StartVertex.OnEdge(this))
{
return(other.StartVertex);
}
else if (other.EndVertex.OnEdge(this))
{
return(other.EndVertex);
}
else
{
return(null);
}
}
// 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);
}
Vertex intersection = this.StartVertex.Translate(a.Scale(s));
if (intersection.Equals(other.StartVertex))
{
return(other.StartVertex);
}
if (intersection.Equals(other.EndVertex))
{
return(other.EndVertex);
}
if (!intersection.OnEdge(other))
{
return(null);
}
return(intersection);
}
