// 给定弧段计算夹角并加入拓扑结构
static void VertexTopo(GeomArc arc, LineSegment seg)
{
if (!vertPool.ContainsKey(seg.Item1))
{
vertPool[seg.Item1] = new SortedDictionary <double, GeomArc>();
}
vertPool[seg.Item1][seg.Angle] = arc;
}
// 从三角序列创建矢量图层
static GeomLayer FromTriangles(IEnumerable <Triangle> triangles, List <GeomPoint> originalPoints)
{
// 创建字典用于反查
var pt_mapper = new Dictionary <Vector2, GeomPoint>();
foreach (GeomPoint tmp in originalPoints)
{
pt_mapper[tmp] = tmp;
}
// 构造矢量图层
GeomLayer result = new GeomLayer(GeomType.Polygon);
var g_points = new Dictionary <Vector2, GeomPoint>();
var g_arcs = new Dictionary <Edge, GeomArc>();
int point_cnt = 0, arc_cnt = 0, poly_cnt = 0;
foreach (Triangle tri in triangles)
{
// 按需创建点
foreach (Vector2 tmp in tri.Points())
{
if (!g_points.ContainsKey(tmp))
{
var new_point = pt_mapper[tmp].Copy(); // 反查原始数据
new_point.id = ++point_cnt;
g_points[tmp] = new_point;
}
}
// 去重获取三边
var arcs = new List <GeomArc>();
foreach (var tmp in tri.Edges())
{
GeomArc cur_arc;
if (g_arcs.ContainsKey(tmp))
{
cur_arc = g_arcs[tmp];
}
else
{
cur_arc = new GeomArc(new GeomPoint[] { g_points[tmp.Item1], g_points[tmp.Item2] }, ++arc_cnt);
g_arcs[tmp] = g_arcs[tmp.Reverse()] = cur_arc;
}
arcs.Add(cur_arc);
}
// 创建三角形
GeomPoly tri_poly = new GeomPoly(arcs, ++poly_cnt);
result.polygons.Add(tri_poly);
}
// 加入点集、边集
result.points.AddRange(g_points.Values);
result.arcs.AddRange(g_arcs.Values);
return(result);
}
// 2.1 从指定弧段与端点开始搜索相连多边形
static void PolyTopoGroup(GeomPoint pt, GeomArc arc)
{
inners = new HashSet <GeomPoly>();
stack = new LinkedList <Tuple <GeomPoint, GeomArc> >();
stack.AddFirst(new Tuple <GeomPoint, GeomArc>(pt, arc));
while (stack.Count > 0)
{
var data = stack.First;
stack.RemoveFirst();
PolyTopoUnit(data.Value);
}
if (inners.Count == 0)
{
return;
}
// 获取并删除外包多边形（面积最大）
GeomPoly outer = null;
if (inners.Count > 1)
{
outer = null;
foreach (var poly in inners)
{
if (outer == null || outer.OuterArea < poly.OuterArea)
{
outer = poly;
}
}
inners.Remove(outer);
}
else
{
outer = inners.First();
}
// 加入待处理孔洞列表
holesGroup.Add(new Tuple <GeomPoly, HashSet <GeomPoly> >(outer, inners));
cPoly.AddRange(inners);
}
// 2.1.1 搜索相连多边形：单元操作，返回当前搜索
static void PolyTopoUnit(Tuple <GeomPoint, GeomArc> data)
{
if (arcUsed.Contains(data))
{
return;
}
var res = new List <Tuple <GeomPoint, GeomArc> >();
// 搜索直到首尾相接
while (true)
{
// 加入当前弧段
res.Add(data);
arcUsed.Add(data);
// 获取下一弧段
GeomPoint prevPt = data.Item1;
GeomArc prevArc = data.Item2;
GeomPoint nextPt = prevArc.First;
if (nextPt == prevPt)
{
nextPt = prevArc.Last;
}
GeomArc nextArc = vertNext[nextPt][data.Item2];
data = new Tuple <GeomPoint, GeomArc>(nextPt, prevArc); // 同弧段不同顶点
if (!arcUsed.Contains(data))
{
stack.AddFirst(data);
}
data = new Tuple <GeomPoint, GeomArc>(nextPt, nextArc);
// 首尾相接时跳出
if (data.Equals(res[0]))
{
break;
}
}
// 创造多边形
var newPoly = new GeomPoly(from pair in res select pair.Item2);
inners.Add(newPoly);
}
