/// <summary>
/// 生成三角剖分结果
/// </summary>
/// <param name="_vertexs">离散顶点集</param>
/// <param name="_polygonBoundsPointIndexs">多边形边界点索引</param>
/// <returns>三角剖分结果</returns>
public static PolygonDelaunayResult2D BuilderDelaunay2D(List <Vector3> _vertexs, List <int> _polygonBoundsPointIndexs)
{
List <PolygonPoint2D> polygonVertexs = new List <PolygonPoint2D>();
Bounds polygonBounds = new Bounds();
PolygonTriangle2D polygonSupperTriangle = new PolygonTriangle2D(new PolygonPoint2D(0, Vector3.zero), new PolygonPoint2D(1, Vector3.zero), new PolygonPoint2D(2, Vector3.zero));
//已完成的剖分三角形
List <PolygonTriangle2D> polygonDelaunayTriangles = new List <PolygonTriangle2D>();
//多边形边界边
Dictionary <int, PolygonEdge2D> polygonBoundsEdgeMaping = new Dictionary <int, PolygonEdge2D>();
if (_vertexs.Count >= 3)
{
#region 分析点
Vector3 max = Vector3.one * float.MinValue;
Vector3 min = Vector3.one * float.MaxValue;
//构建顶点
for (int i = 0; i < _vertexs.Count; i++)
{
polygonVertexs.Add(new PolygonPoint2D(i, _vertexs[i]));
min.x = Mathf.Min(min.x, _vertexs[i].x);
min.y = Mathf.Min(min.y, _vertexs[i].y);
min.z = Mathf.Min(min.z, _vertexs[i].z);
max.x = Mathf.Max(max.x, _vertexs[i].x);
max.y = Mathf.Max(max.y, _vertexs[i].y);
max.z = Mathf.Max(max.z, _vertexs[i].z);
}
PolygonEdge2D tempPolygonEdge2D = null;
if (_polygonBoundsPointIndexs != null && _polygonBoundsPointIndexs.Count > 0)
{
for (int i = 0; i < _polygonBoundsPointIndexs.Count; i++)
{
if (i < _polygonBoundsPointIndexs.Count - 1)
{
tempPolygonEdge2D = new PolygonEdge2D(polygonVertexs[i], polygonVertexs[i + 1]);
}
else
{
tempPolygonEdge2D = new PolygonEdge2D(polygonVertexs[i], polygonVertexs[0]);
}
polygonBoundsEdgeMaping.Add(tempPolygonEdge2D.key, tempPolygonEdge2D);
}
}
//x轴从左往右排序
polygonVertexs.Sort((x, y) => { return(x.position.x >= y.position.x ? 1 : -1); });
//y轴从下往上排序
polygonVertexs.Sort((x, y) => { return((x.position.x == y.position.x && x.position.y >= y.position.y) ? 1 : -1); });
//构建一个包含所有点集的三角形
polygonBounds = new Bounds(Vector3.Lerp(min, max, 0.5f), Vector3.zero);
polygonBounds.SetMinMax(min, max);
float raudis = Vector3.Distance(polygonBounds.min, polygonBounds.max) * 0.6f;
Vector3 tvc = polygonBounds.center + Vector3.back * raudis;
Vector3 tvl = polygonBounds.min + Vector3.back * (raudis - Mathf.Abs(polygonBounds.extents.z));
Vector3 axis = tvc - polygonBounds.center;
Vector3 vc = (tvl - tvc).normalized * raudis * 2;
Vector3 tp0 = vc + tvc;
vc = Quaternion.AngleAxis(120, axis) * vc;
Vector3 tp1 = vc + tvc;
vc = Quaternion.AngleAxis(120, axis) * vc;
Vector3 tp2 = vc + tvc;
tp0.z = tp1.z = tp2.z = 0;
polygonSupperTriangle = new PolygonTriangle2D(new PolygonPoint2D(_vertexs.Count, tp0, true), new PolygonPoint2D(_vertexs.Count + 1, tp1, true), new PolygonPoint2D(_vertexs.Count + 2, tp2, true));
#endregion
#region 角剖分
//缓存的剖分三角形
List <PolygonTriangle2D> tempDelaunayTriangles = new List <PolygonTriangle2D>();
//等待检测的三角形
List <PolygonTriangle2D> validateTriangles = new List <PolygonTriangle2D>()
{
polygonSupperTriangle
};
//从第一个顶点开始，进行三角剖分检测
int count = polygonVertexs.Count;
for (int i = 0; i < count; i++)
{
List <PolygonTriangle2D> delTris = FindDelaunayTriangle(polygonVertexs[i], ref validateTriangles);
if (delTris.Count > 0)
{
tempDelaunayTriangles.AddRange(delTris);
}
}
tempDelaunayTriangles.AddRange(validateTriangles);
#endregion
#region 除超级三角形
//需要补边的三角形
List <PolygonTriangle2D> pushEdgeTriangles = new List <PolygonTriangle2D>();
int supperPointCount = 0;
foreach (PolygonTriangle2D tri in tempDelaunayTriangles)
{
//缓存三角形有任意点是超三角形的点
supperPointCount = 0;
foreach (PolygonPoint2D v in tri.vertexs)
{
if (v.isSupperPoint)
{
supperPointCount++;
}
}
if (supperPointCount > 0)
{
pushEdgeTriangles.Add(tri);
}
else
{
polygonDelaunayTriangles.Add(tri);
foreach (PolygonEdge2D edge in tri.edges)
{
polygonBoundsEdgeMaping.Remove(edge.key);
}
}
}
#endregion
#region 对删除的超级三角形与边界比对，补充未绘制的边界三角形
//点索引
int pointIndex = _vertexs.Count;
//交点
Vector3 point = Vector3.zero;
//边是否相交
bool isIntersection = false;
//边交点
Dictionary <int, Dictionary <int, PolygonPoint2D> > edgePoint = new Dictionary <int, Dictionary <int, PolygonPoint2D> >();
//三角形被边界线切割后的多边形点
Dictionary <int, PolygonPoint2D> polygonPoints = new Dictionary <int, PolygonPoint2D>();
//检测三角形
foreach (PolygonTriangle2D tri in pushEdgeTriangles)
{
polygonPoints.Clear();
foreach (PolygonEdge2D triEdge in tri.edges)
{
foreach (PolygonEdge2D edge in polygonBoundsEdgeMaping.Values)
{
#region 求交点
isIntersection = false;
point = Vector3.zero;
if (edgePoint.ContainsKey(triEdge.key) && edgePoint[triEdge.key].ContainsKey(edge.key))
{
isIntersection = true;
}
else if (Geometry2DUtility.EdgeIntersection(triEdge, edge, ref point))
{
isIntersection = true;
if (!edgePoint.ContainsKey(triEdge.key))
{
edgePoint.Add(triEdge.key, new Dictionary <int, PolygonPoint2D>());
}
if (!edgePoint[triEdge.key].ContainsKey(edge.key))
{
edgePoint[triEdge.key].Add(edge.key, new PolygonPoint2D(pointIndex, point));
}
polygonVertexs.Add(edgePoint[triEdge.key][edge.key]);
pointIndex++;
}
if (isIntersection)
{
//加入交点
if (!polygonPoints.ContainsKey(edgePoint[triEdge.key][edge.key].index))
{
polygonPoints.Add(edgePoint[triEdge.key][edge.key].index, edgePoint[triEdge.key][edge.key]);
}
}
#endregion
}
}
if (polygonPoints.Count > 0)
{
//如果有任意交点，保留三角形非超级点
foreach (PolygonPoint2D p in tri.vertexs)
{
if (!p.isSupperPoint)
{
if (!polygonPoints.ContainsKey(p.index))
{
polygonPoints.Add(p.index, p);
}
}
}
if (polygonPoints.Count >= 3)
{
List <PolygonPoint2D> pps = new List <PolygonPoint2D>(polygonPoints.Values);
if (pps.Count == 3)
{
polygonDelaunayTriangles.Add(
new PolygonTriangle2D(pps[0], pps[1], pps[2]));
}
else if (pps.Count == 4)
{
//如果有两个交点，则pps中前两个是交点，后两个是原三角形的两个顶点
//交点与顶点各取一点组成两条边，然后看两条边是否相交，相交则是对角线，不相交则不是
//找到对角线后，与非对角线点的另外一个交点和顶点组成新的两个三角形
PolygonEdge2D edge1 = new PolygonEdge2D(pps[0], pps[2]);
PolygonEdge2D edge2 = new PolygonEdge2D(pps[1], pps[3]);
if (Geometry2DUtility.EdgeIntersection(edge1, edge2))
{
//0,2,1 和0,2,3 组成两个新的三角形
polygonDelaunayTriangles.Add(
new PolygonTriangle2D(pps[0], pps[2], pps[1]));
polygonDelaunayTriangles.Add(
new PolygonTriangle2D(pps[0], pps[2], pps[3]));
}
else
{
//0,3,1 和 0,3,2 组成两个新的三角形
polygonDelaunayTriangles.Add(
new PolygonTriangle2D(pps[0], pps[3], pps[1]));
polygonDelaunayTriangles.Add(
new PolygonTriangle2D(pps[0], pps[3], pps[2]));
}
}
}
}
}
#endregion
}
else
{
throw new UnityException("There are not enough vertexs to constitute polygon,the vertexs are least of three.");
}
return(new PolygonDelaunayResult2D(polygonVertexs, polygonBounds, polygonSupperTriangle, polygonDelaunayTriangles));
}