public DCELHalfEdge2D(DCELVertex2D origin, DCELFace2D face, DCELHalfEdge2D twin, DCELHalfEdge2D next)
{
Origin = origin;
Face = face;
Twin = twin;
Next = next;
}
/// <summary>
/// Verifica se la faccia è convessa. Un poligono semplice è strettamente convesso se ogni
/// angolo interno è strettamente inferiore a 180 gradi.
/// </summary>
/// <returns>True se la faccia è convessa, false altrimenti.</returns>
public bool IsConvex()
{
DCELHalfEdge2D he = this.Edge;
DCELHalfEdge2D prev = he.Previous();
DCELVertex2D first = he.Origin;
do
{
Vector v1 = new Vector(
prev.Origin.Coordinates.X - he.Origin.Coordinates.X,
prev.Origin.Coordinates.Y - he.Origin.Coordinates.Y);
Vector v2 = new Vector(
he.Next.Origin.Coordinates.X - he.Origin.Coordinates.X,
he.Next.Origin.Coordinates.Y - he.Origin.Coordinates.Y);
double dotProduct = (v1.X * v2.X + v1.Y * v2.Y);
double norm1 = Math.Sqrt(Math.Pow(v1.X, 2) + Math.Pow(v1.Y, 2));
double norm2 = Math.Sqrt(Math.Pow(v2.X, 2) + Math.Pow(v2.Y, 2));
double angle = (Math.Acos(dotProduct / (norm1 * norm2)) * 180) / Math.PI;
if (angle > 180)
{
return(false);
}
prev = he;
he = he.Next;
}while (he.Origin != first);
//returns true if every internal angle is less than or equal to 180 degrees
return(true);
}
public bool AddHalfEdge(DCELHalfEdge2D edge)
{
edgeList.Add(edge);
edgeCount++;
return(true);
}
public bool RemoveHalfEdge(DCELHalfEdge2D edge)
{
if (edgeList.Remove(edge))
{
edgeCount--;
return(true);
}
return(false);
}
/// <summary>
/// Restituisce l'HalfEdge precedente.
/// </summary>
/// <returns>DCELHalfEdge.</returns>
public DCELHalfEdge2D Previous()
{
DCELHalfEdge2D he = this;
do
{
he = he.Next;
}while (he.Next.Origin != this.Origin);
return(he);
}
/// <summary>
/// Restituisce i lati della faccia.
/// </summary>
/// <returns>DCELHalfEdge collection.</returns>
public IEnumerable <DCELHalfEdge2D> Sides()
{
DCELHalfEdge2D he = this.Edge;
DCELVertex2D first = he.Origin;
do
{
yield return(he);
he = he.Next;
}while (he.Origin != first);
}
/// <summary>
/// Restituisce tutte le facce confinanti.
/// </summary>
/// <returns>DCELFace collection.</returns>
public IEnumerable <DCELFace2D> Neighbours()
{
DCELHalfEdge2D he = this.Edge;
DCELVertex2D first = he.Origin;
do
{
if (he.Twin != null)
{
if (!he.Twin.Face.IsInfinite())
{
yield return(he.Twin.Face);
}
}
he = he.Next;
}while (he.Origin != first);
}
/// <summary>
/// Restituisce tutti gli HalfEdge che partono da questo vertice.
/// </summary>
/// <returns>DCELHalfEdge collection.</returns>
public IEnumerable <DCELHalfEdge2D> LeavingEdges()
{
if (this.Leaving == null)
{
yield break;
}
DCELHalfEdge2D he = this.Leaving;
do
{
yield return(he);
he = he.Previous().Twin;
if (he == null)
{
yield break;
}
}while (he != this.Leaving);
}
public DCELVertex2D(Point coordinates, DCELHalfEdge2D leaving)
{
Coordinates = coordinates;
Leaving = leaving;
}
public DCELVertex2D(double x, double y, DCELHalfEdge2D leaving)
{
Coordinates = new Point(x, y);
Leaving = leaving;
}
/// <summary>
/// Crea una nuova istanza di DCELFace non infinita.
/// </summary>
/// <param name="edge">Un singolo HalfEdge che ha questa faccia come sua faccia.</param>
/// <param name="normal">La normale della faccia.</param>
public DCELFace2D(DCELHalfEdge2D edge) : this()
{
this.edge = edge;
}
public bool Contains(DCELHalfEdge2D edge)
{
return(edgeList.Contains(edge));
}
