/// <summary>
/// Whether the two line segment intersect each other.
/// </summary>
/// <param name="lineSegment">the other line segment.</param>
/// <returns>true if intersect.</returns>
public bool Intersects(LineSegment2D lineSegment)
{
if (!this.ExtentIntersects(lineSegment))
{
return(false);
}
return(lineSegment.LineIntersects(this) && this.LineIntersects(lineSegment));
}
private LineSegment2D ChooseDiviser(LineSegment2D lineSegment)
{
for (int i = 0; i < CurrentPolygon.VertexCount; i++)
{
LineSegment2D Edge = CurrentPolygon.GetEdge(i);
if (Edge == lineSegment || Edge.Intersects(lineSegment) || !Edge.LineIntersects(lineSegment))
{
continue;
}
Point2D divPoint = lineSegment.ToLine().Intersects(Edge.ToLine());
if (lineSegment.Contains(divPoint))
{
continue;
}
LineSegment2D divLine = new LineSegment2D(lineSegment.LastPoint, divPoint);
if (divLine.Contains(lineSegment.FirstPoint))
{
//divLine = new LineSegment2D(lineSegment.FirstPoint, divPoint);
continue;
}
/*if (CurrentPolygon.InflectsEdge(divLine))
* {
* int ssi = 0;
* }*/
if (!CurrentPolygon.Contains(divLine))
{
continue;
}
if (divPoint == this.LastPoint)
{
///need trace here
return(divLine);
}
if (this.isApart(divLine, this.CurrentPointIndex, this.LastPointIndex))
{
return(divLine);
}
}
return(null);
}
/// <summary>
/// Whether the two line segment intersect each other.
/// </summary>
/// <param name="lineSegment">the other line segment.</param>
/// <returns>true if intersect.</returns>
public bool Intersects(LineSegment2D lineSegment)
{
if (!this.ExtentIntersects(lineSegment))
{
return false;
}
return lineSegment.LineIntersects(this) && this.LineIntersects(lineSegment);
}
/// <summary>
/// Construct a minimum link path of a polygon.
/// </summary>
public void BuildPath()
{
this.LinkDivisers.Clear();
Point2D CurrentPoint = this.LastPoint;
Point2D IntersectPoint = null;
LineSegment2D CurrentLine = null;
LineSegment2D IntersectLine = null;
for (int i = this.Divisers.Count - 1; i >= 0; i--)
{
double position = -1.0;
Polygon2D currentPolygon = this.SubDivision[i + 1];
CurrentLine = this.Divisers[i];
if (CurrentLine.Contains(CurrentPoint))
{
this.LinkDivisers.Add(CurrentPoint);
Vector2D vector = CurrentLine.ToVector().Normal().Normalize();
IntersectPoint = CurrentLine.MidPoint + vector;
if (!this.SubDivision[i].Contains(IntersectPoint))
{
vector = -vector;
}
double length = CurrentLine.Length;
LineSegment2D testLine = null;
do
{
IntersectPoint = CurrentLine.MidPoint + vector * length;
length /= 2;
testLine = new LineSegment2D(CurrentPoint, IntersectPoint);
} while (!this.SubDivision[i].Contains(testLine));
continue;
}
for (int j = 0; j < currentPolygon.VertexCount; j++)
{
Point2D point = currentPolygon.GetPoint(j);
if (CurrentPoint == point)
{
continue;
}
LineSegment2D lineSegment = new LineSegment2D(CurrentPoint, point);
if (currentPolygon.Contains(lineSegment) || currentPolygon.isEdge(lineSegment))
{
if (CurrentLine.LineIntersects(lineSegment))
{
IntersectPoint = CurrentLine.ToLine().Intersects(lineSegment.ToLine());
if (position < 0)
{
position = CurrentLine.GetPosition(IntersectPoint);
}
else
{
position += CurrentLine.GetPosition(IntersectPoint);
position /= 2;
}
}
}
}
if (position < -0.5)
{
CurrentPoint = IntersectPoint + IntersectLine.ToVector().Normalize();
i++;
continue;
}
this.LinkDivisers.Add(CurrentPoint);
IntersectPoint = CurrentLine.GetPoint(position);
IntersectLine = new LineSegment2D(CurrentPoint, IntersectPoint);
double extend = IntersectLine.Length;
do
{
extend /= 2;
CurrentPoint = IntersectLine.Extend(extend);
} while (!this.SubDivision[i].Contains(CurrentPoint));
//CurrentPoint = CurrentLine.GetPoint(position);
}
CurrentLine = new LineSegment2D(CurrentPoint, this.FirstPoint);
if (this.Parent.Contains(CurrentLine))
{
this.LinkDivisers.Add(CurrentPoint);
this.LinkDivisers.Add(this.FirstPoint);
}
else if (IntersectLine != null)
{
CurrentPoint = IntersectPoint + IntersectLine.ToVector().Normalize();
this.LinkDivisers.Add(CurrentPoint);
this.LinkDivisers.Add(this.FirstPoint);
}
else
{
Vector2D vector = CurrentLine.ToVector().Normal().Normalize();
IntersectPoint = CurrentLine.MidPoint + vector;
if (!this.Parent.Contains(IntersectPoint))
{
vector = -vector;
}
IntersectPoint = CurrentLine.MidPoint;
double length = CurrentLine.Length;
do
{
length /= 2;
CurrentPoint = IntersectPoint + vector * length;
}while (!this.Parent.Contains(CurrentPoint));
this.LinkDivisers.Add(this.LastPoint);
this.LinkDivisers.Add(CurrentPoint);
this.LinkDivisers.Add(this.FirstPoint);
}
}