private static List <Polygon> LinkToPolygon_Union()
{
//保存合并后的多边形数组
var rcNodes = new List <Vector2>();
var startV = GetLeftBottomVertex();
PolygonNode node = null;
if (GetNodeIndex(lnSubject, startV) != -1)
{
node = lnSubject[GetNodeIndex(lnSubject, startV)];
}
else if (GetNodeIndex(lnClip, startV) != -1)
{
node = lnClip[GetNodeIndex(lnClip, startV)];
}
while (node != null)
{
rcNodes.Add(node.vertex);
if (node.isIntersectPoint)
{
if (node.isOutPoint == false) //该交点为进点（跟踪主多边形边界）
{
if (node.isSubject == false) //当前点在副多边形中
{
node = node.other; //切换到主多边形中
}
}
else //该交点为出点（跟踪副多边形边界）
{
if (node.isSubject) //当前点在主多边形中
{
node = node.other; //切换到副多边形中
}
}
}
if (node.next == null) //末尾点返回到开始点
{
node = node.isSubject ? lnSubject[0] : lnClip[0];
}
else
{
node = node.next;
}
//与首点相同，生成一个多边形
if (node.vertex == rcNodes[0])
{
break;
}
}
var ret = new List <Polygon> {
new Polygon(rcNodes.ToArray())
};
return(ret);
}
/// <summary>
/// 创建polygon的nodes，最后一个node的next指向null
/// </summary>
/// <param name="polygon"></param>
/// <param name="isIntersectPoint"></param>
/// <param name="isSubject"></param>
/// <returns></returns>
public static List <PolygonNode> CreateNodes(Polygon polygon, bool isIntersectPoint, bool isSubject)
{
var nodes = new List <PolygonNode>();
PolygonNode node;
for (var i = 0; i < polygon.vertexList.Count; i++)
{
node = new PolygonNode(polygon.vertexList[i], isIntersectPoint, isSubject);
if (i > 0)
{
nodes[i - 1].next = node;
}
nodes.Add(node);
}
return(nodes);
}
private static int IntersectPoint_Union()
{
var insCnt = 0; //交点数
var nSubjectCur = lnSubject[0];
PolygonNode nClipCur;
Line lSubject;
Line lClip;
bool hasIntersectPoint; //是否有交点
while (nSubjectCur != null) //主多边形
{
lSubject = nSubjectCur.next == null
? new Line(nSubjectCur.vertex, lnSubject[0].vertex)
: new Line(nSubjectCur.vertex, nSubjectCur.next.vertex);
//奇异情况:与裁剪多边形重合的主多边形的边不参与求交点 http://course.baidu.com/view/58a00497daef5ef7ba0d3c52.html
if (IsOverLap_Union(lSubject, pClip))
{
nSubjectCur = nSubjectCur.next;
continue;
}
nClipCur = lnClip[0];
hasIntersectPoint = false;
while (nClipCur != null)
{
lClip = nClipCur.next == null
? new Line(nClipCur.vertex, lnClip[0].vertex)
: new Line(nClipCur.vertex, nClipCur.next.vertex);
var lineRelation = lSubject.Intersection(lClip, out var intersectPoint);
if (lineRelation == Line.LineClassification.SegmentsIntersect) //相交
{
var a_on_lClip = lClip.ClassifyPoint(lSubject.pointA) == PointClassification.OnSegment;
var a_index_of_lnClip = GetNodeIndex(lnClip, lSubject.pointA);
var b_on_lClip = lClip.ClassifyPoint(lSubject.pointB) == PointClassification.OnSegment;
var b_index_of_lnClip = GetNodeIndex(lnClip, lSubject.pointB);
//主多边形边上的顶点A是在副多边形上
if (a_on_lClip && (a_index_of_lnClip == -1 ||
a_index_of_lnClip != -1 && lnClip[a_index_of_lnClip].isChecked == false))
{
insCnt++;
PolygonNode nSubjectInter = null;
PolygonNode nClipInter = null;
if (GetNodeIndex(lnSubject, lSubject.pointA) == -1)
{
nSubjectInter = new PolygonNode(lSubject.pointA, true, true);
nSubjectInter.isChecked = true;
lnSubject.Add(nSubjectInter);
nSubjectInter.next = nSubjectCur.next;
nSubjectCur.next = nSubjectInter;
hasIntersectPoint = true;
}
else
{
nSubjectInter = lnSubject[GetNodeIndex(lnSubject, lSubject.pointA)];
nSubjectInter.isIntersectPoint = true;
nSubjectInter.isChecked = true;
}
if (GetNodeIndex(lnClip, lSubject.pointA) == -1)
{
nClipInter = new PolygonNode(lSubject.pointA, true, false);
nClipInter.isChecked = true;
lnClip.Add(nClipInter);
nClipInter.next = nClipCur.next;
nClipCur.next = nClipInter;
}
else
{
nClipInter = lnClip[GetNodeIndex(lnClip, lSubject.pointA)];
nClipInter.isChecked = true;
nClipInter.isIntersectPoint = true;
}
//双向引用
nSubjectInter.other = nClipInter;
nClipInter.other = nSubjectInter;
if (!IsOutter(lSubject, pClip))
{
nSubjectInter.isOutPoint = true;
nClipInter.isOutPoint = true;
}
else
{
nSubjectInter.isOutPoint = false;
nClipInter.isOutPoint = false;
}
}
//主多边形边上的顶点B是在副多边形上
if (b_on_lClip && (b_index_of_lnClip == -1 ||
b_index_of_lnClip != -1 && lnClip[b_index_of_lnClip].isChecked == false))
{
insCnt++;
PolygonNode nSubjectInter = null;
PolygonNode nClipInter = null;
if (GetNodeIndex(lnSubject, lSubject.pointB) == -1)
{
nSubjectInter = new PolygonNode(lSubject.pointB, true, true);
nSubjectInter.isChecked = true;
lnSubject.Add(nSubjectInter);
nSubjectInter.next = nSubjectCur.next;
nSubjectCur.next = nSubjectInter;
hasIntersectPoint = true;
}
else
{
nSubjectInter = lnSubject[GetNodeIndex(lnSubject, lSubject.pointB)];
nSubjectInter.isIntersectPoint = true;
nSubjectInter.isChecked = true;
}
if (GetNodeIndex(lnClip, lSubject.pointB) == -1)
{
nClipInter = new PolygonNode(lSubject.pointB, true, false);
nClipInter.isChecked = true;
lnClip.Add(nClipInter);
nClipInter.next = nClipCur.next;
nClipCur.next = nClipInter;
}
else
{
nClipInter = lnClip[GetNodeIndex(lnClip, lSubject.pointB)];
nClipInter.isChecked = true;
nClipInter.isIntersectPoint = true;
}
nSubjectInter.other = nClipInter;
nClipInter.other = nSubjectInter;
if (!IsOutter(lSubject, pClip))
{
nSubjectInter.isOutPoint = false;
nClipInter.isOutPoint = false;
}
else
{
nSubjectInter.isOutPoint = true;
nClipInter.isOutPoint = true;
}
}
//交点不在顶点上的情况（主多边形的一条线段肯能跟副多边形的多条边相交）
//忽略交点已在顶点列表中的
if (GetNodeIndex(lnSubject, intersectPoint.Value) == -1)
{
insCnt++;
///////// 插入交点
var nSubjectInter = new PolygonNode(intersectPoint.Value, true, true);
nSubjectInter.isChecked = true;
var nClipInter = new PolygonNode(intersectPoint.Value, true, false);
nClipInter.isChecked = true;
lnSubject.Add(nSubjectInter);
lnClip.Add(nClipInter);
//双向引用
nSubjectInter.other = nClipInter;
nClipInter.other = nSubjectInter;
//插入
nSubjectInter.next = nSubjectCur.next;
nSubjectCur.next = nSubjectInter;
nClipInter.next = nClipCur.next;
nClipCur.next = nClipInter;
//出点
if (lSubject.ClassifyPoint(lClip.pointB) == PointClassification.LeftSide)
{
nSubjectInter.isOutPoint = true;
nClipInter.isOutPoint = true;
}
else
{
nSubjectInter.isOutPoint = false;
nClipInter.isOutPoint = false;
}
hasIntersectPoint = true; //有交点
//有交点，返回重新处理
break;
}
}
nClipCur = nClipCur.next;
}
//如果没有交点继续处理下一个边，否则重新处理该点与插入的交点所形成的线段
//原因：这条线段上还可能有其他的交点，注意hasIntersectPoint是只检测一次true就break，而且无法确定同一条边的交点先后顺序，所以如果有交点的时候要重新处理该点与插入的交点所形成的线段
if (hasIntersectPoint == false)
{
nSubjectCur = nSubjectCur.next;
}
}
return(insCnt);
}
private static int IntersectPoint_Cut()
{
var insCnt = 0; //交点数
var nSubjectCur = lnSubject[0];
PolygonNode nClipCur;
Line lSubject;
Line lClip;
bool isHasIntersectPoint; //是否有交点
while (nSubjectCur != null) //主多边形
{
lSubject = nSubjectCur.next == null
? new Line(nSubjectCur.vertex, lnSubject[0].vertex)
: new Line(nSubjectCur.vertex, nSubjectCur.next.vertex);
//奇异情况:与裁剪多边形重合的主多边形的边不参与求交点 http://course.baidu.com/view/58a00497daef5ef7ba0d3c52.html
if (IsOverLap_Cut(lSubject, pClip))
{
nSubjectCur = nSubjectCur.next;
continue;
}
nClipCur = lnClip[0];
isHasIntersectPoint = false;
while (nClipCur != null)
{
lClip = nClipCur.next == null
? new Line(nClipCur.vertex, lnClip[0].vertex)
: new Line(nClipCur.vertex, nClipCur.next.vertex);
var lineRelation = lSubject.Intersection(lClip, out var intersectPoint);
if (lineRelation == Line.LineClassification.SegmentsIntersect) //相交
{
if (lClip.ClassifyPoint(lSubject.pointA) == PointClassification.OnSegment &&
GetNodeIndex(lnClip, lSubject.pointA) == -1)
{
if (!IsOutter(lSubject, pClip))
{
insCnt++;
var nSubjectInter = nSubjectCur;
nSubjectInter.isIntersectPoint = true;
var nClipInter = new PolygonNode(lSubject.pointA, true, false);
lnClip.Add(nClipInter);
nClipInter.other = nSubjectInter;
nSubjectInter.other = nClipInter;
nClipCur = lnClip[GetNodeIndex(lnClip, lClip.pointA)];
nClipInter.next = nClipCur.next;
nClipCur.next = nClipInter;
nSubjectInter.isOutPoint = false;
nClipInter.isOutPoint = false;
}
}
if (lClip.ClassifyPoint(lSubject.pointB) == PointClassification.OnSegment &&
GetNodeIndex(lnClip, lSubject.pointB) == -1)
{
if (!IsOutter(lSubject, pClip))
{
insCnt++;
var nSubjectInter = lnSubject[GetNodeIndex(lnSubject, lSubject.pointB)];
nSubjectInter.isIntersectPoint = true;
var nClipInter = new PolygonNode(lSubject.pointB, true, false);
lnClip.Add(nClipInter);
nSubjectInter.other = nClipInter;
nClipInter.other = nSubjectInter;
nClipInter.next = nClipCur.next;
nClipCur.next = nClipInter;
nSubjectInter.isOutPoint = true;
nClipInter.isOutPoint = true;
}
}
//忽略交点已在顶点列表中的
if (GetNodeIndex(lnSubject, intersectPoint.Value) == -1)
{
insCnt++;
///////// 插入交点
var nSubjectInter = new PolygonNode(intersectPoint.Value, true, true);
var nClipInter = new PolygonNode(intersectPoint.Value, true, false);
lnSubject.Add(nSubjectInter);
lnClip.Add(nClipInter);
//双向引用
nSubjectInter.other = nClipInter;
nClipInter.other = nSubjectInter;
//插入
nSubjectInter.next = nSubjectCur.next;
nSubjectCur.next = nSubjectInter;
nClipInter.next = nClipCur.next;
nClipCur.next = nClipInter;
//出点
if (lSubject.ClassifyPoint(lClip.pointB) == PointClassification.RightSide)
{
nSubjectInter.isOutPoint = true;
nClipInter.isOutPoint = true;
}
else
{
nSubjectInter.isOutPoint = false;
nClipInter.isOutPoint = false;
}
isHasIntersectPoint = true; //有交点
//有交点，返回重新处理
break;
}
}
nClipCur = nClipCur.next;
}
//如果没有交点继续处理下一个边，否则重新处理该点与插入的交点所形成的线段
//原因：这条线段上还可能有其他的交点，注意hasIntersectPoint是只检测一次true就break，而且无法确定同一条边的交点先后顺序，所以如果有交点的时候要重新处理该点与插入的交点所形成的线段
if (isHasIntersectPoint == false)
{
nSubjectCur = nSubjectCur.next;
}
}
return(insCnt);
}
