/// <summary>
/// 查找相交线段
/// </summary>
/// <param name="lineSegs"></param>
/// <returns></returns>
public Vector2[] FindIntersections(LineSegment2D[] lineSegs)
{
this.Clear();
if (lineSegs == null || lineSegs.Length == 0)
{
return(null);
}
VertexSegment2D[] segs = new VertexSegment2D[lineSegs.Length];
for (var i = 0; i < lineSegs.Length; i++)
{
var seg = new VertexSegment2D(lineSegs[i]);
segs[i] = seg;
_upLineSegment.Add(seg.Up, seg);
_lowLineSegment.Add(seg.Low, seg);
_sortedVertexes.Add(seg.Up);
_sortedVertexes.Add(seg.Low);
}
while (_sortedVertexes.Count > 0)
{
var point = _sortedVertexes.Min;
_sortedVertexes.Remove(point);
HandleEventPoint(point);
}
return(_sortedVertexes.ToArray());
}
/// <summary>
/// 处理事件点
/// </summary>
/// <param name="point"></param>
/// <returns></returns>
private SortedSet <VertexSegment2D> HandleEventPoint(Vector2 point)
{
var upList = new List <VertexSegment2D>();
foreach (var item in _upLineSegment.Values)
{
if (item.Up == point)
{
upList.Add(item);
}
}
var lowList = new List <VertexSegment2D>();
var containsList = new List <VertexSegment2D>();
_statusTree.InorderTraversal((a) =>
{
if (a.Data.Low == point)
{
lowList.Add(a.Data);
}
if (a.Data.Line.Contains(point))
{
containsList.Add(a.Data);
}
});
var allSeg = new SortedSet <VertexSegment2D>();
allSeg.UnionWith(upList);
allSeg.UnionWith(lowList);
allSeg.UnionWith(containsList);
List <Vector2> intersectionPoints = new List <Vector2>();
if (allSeg.Count != 0)
{
return(allSeg);
}
var deleteSeg = new SortedSet <VertexSegment2D>();
deleteSeg.UnionWith(lowList);
deleteSeg.UnionWith(containsList);
if (deleteSeg.Count > 0)
{
var ary = new VertexSegment2D[deleteSeg.Count];
deleteSeg.CopyTo(ary);
for (var i = 0; i < ary.Length; i++)
{
_statusTree.Remove(ary[i]);
}
}
var addSeg = new SortedSet <VertexSegment2D>();
containsList.Reverse();
addSeg.UnionWith(upList);
addSeg.UnionWith(containsList);
if (addSeg.Count > 0)
{
var ary = new VertexSegment2D[addSeg.Count];
addSeg.CopyTo(ary);
for (var i = 0; i < ary.Length; i++)
{
_statusTree.Add(ary[i]);
}
}
return(allSeg);
}
