}// func
private static void getPolyMergeInfo(int polyAPointer, int polyBPointer,
int[] polys, int[] verts,
int maxVertsPerPoly, out int[] outResult)
{
outResult = new int[3];
outResult[0] = -1;
outResult[1] = -1;
outResult[2] = -1;
int vertCountA = PolyMeshField.getPolyVertCount(polyAPointer, polys, maxVertsPerPoly);
int vertCountB = PolyMeshField.getPolyVertCount(polyBPointer, polys, maxVertsPerPoly);
//减2 是因为合并了一条边，少了两个顶点
if (vertCountA + vertCountB - 2 > maxVertsPerPoly)
{
return;
}
for (int iPolyVertA = 0; iPolyVertA < vertCountA; ++iPolyVertA)
{
int iVertA = polys[polyAPointer + iPolyVertA];
int iVertANext = polys[polyAPointer + getNextIndex(iPolyVertA, vertCountA)];
for (int iPolyVertB = 0; iPolyVertB < vertCountB; ++iPolyVertB)
{
int iVertB = polys[polyBPointer + iPolyVertB];
int iVertBNext = polys[polyBPointer + getNextIndex(iPolyVertB, vertCountB)];
/*
* 同一种顶点顺序，两个点是重合的话， 就是共享边了。
* A/B+1
* \
* \
* A+1/B
*/
if (iVertA == iVertBNext &&
iVertANext == iVertB)
{
outResult[1] = iPolyVertA;
outResult[2] = iPolyVertB;
}
} //iPolyB
} // iPolyA
if (-1 == outResult[1])
{
return;
}
//对顺时针包含的多边形有效
int pSharedVertMinus;
int pSharedVert;
int pSharedVertPlus;
//为什么是3呢?是因为xyz为一组
//A-1
pSharedVertMinus = polys[polyAPointer + getPreviousIndex(outResult[1], vertCountA)] * 3;
//A
pSharedVert = polys[polyAPointer + outResult[1]] * 3;
//????TODO，用B的，还是B+2了卧槽。。。
//我艹，B+2 对应的就是图上的A+1，这个并不是真是意义是A点的下一个点
pSharedVertPlus = polys[polyBPointer + ((outResult[2] + 2) % vertCountB)] * 3;
if (!isLeft(verts[pSharedVert], verts[pSharedVert + 2],
verts[pSharedVertMinus], verts[pSharedVertMinus + 2],
verts[pSharedVertPlus], verts[pSharedVertPlus + 2]
))
{
return;
}
pSharedVertMinus = polys[polyBPointer + getPreviousIndex(outResult[2], vertCountB)] * 3;
pSharedVert = polys[polyBPointer + outResult[2]] * 3;
pSharedVertPlus = polys[polyAPointer + ((outResult[1] + 2) % vertCountA)] * 3;
if (!isLeft(verts[pSharedVert], verts[pSharedVert + 2],
verts[pSharedVertMinus], verts[pSharedVertMinus + 2],
verts[pSharedVertPlus], verts[pSharedVertPlus + 2]))
{
return;
}
//共享边
pSharedVertMinus = polys[polyAPointer + outResult[1]] * 3;
pSharedVert = polys[polyAPointer + getNextIndex(outResult[1], vertCountA)] * 3;
int deltaX = verts[pSharedVertMinus + 0] - verts[pSharedVert + 0];
int deltaZ = verts[pSharedVertMinus + 2] - verts[pSharedVert + 2];
outResult[0] = deltaX * deltaX + deltaZ * deltaZ;
}
public PolyMeshField build(ContourSet contours)
{
if (null == contours ||
0 == contours.size())
{
Logger.LogError("[PolyMeshFieldBuild][build]Param Error");
return(null);
}
PolyMeshField result = new PolyMeshField(contours.boundsMin(),
contours.boundsMax(),
contours.cellSize(),
contours.cellHeight(),
mMaxVertsPerPoly);
int sourceVertCount = 0;
int maxPossiblePolygons = 0;
int maxVertsPerContour = 0;
for (int contourIndex = 0; contourIndex < contours.size(); ++contourIndex)
{
int count = contours.get(contourIndex).vertCount;
sourceVertCount += count;
//过 n 边形的一个顶点，能把n边形最多分成 n - 2 三角形
maxPossiblePolygons += count - 2;
maxVertsPerContour = Math.Max(maxVertsPerContour, count);
}
if (sourceVertCount - 1 > DEFLAG)
{
Logger.LogError("[PolyMeshFieldBuilder][build]sourceVertCount out of Range|{0}|{1}", DEFLAG, sourceVertCount);
return(null);
}
int[] globalVerts = new int[sourceVertCount * 3]; //存的是索引，存的是整个轮廓的
int globalVertCount = 0;
int[] globalPolys = new int[maxPossiblePolygons * mMaxVertsPerPoly]; //存的也是索引
for (int i = 0; i < globalPolys.Length; ++i)
{
globalPolys[i] = PolyMeshField.NULL_INDEX;
}
int[] globalRegions = new int[maxPossiblePolygons];
int globalPolyCount = 0;
int[] contourToGlobalIndicesMap = new int[maxVertsPerContour]; //存的也是索引
Dictionary <int, int> vertIndices = new Dictionary <int, int>();
List <int> workingIndices = new List <int>(maxVertsPerContour);
List <int> workingTriangles = new List <int>(maxVertsPerContour);
//TODO 为什么要+1？
int[] workingPolys = new int[(maxVertsPerContour + 1) * mMaxVertsPerPoly];
int workingPolyCount = 0;
int[] mergeInfo = new int[3];
int[] mergedPoly = new int[mMaxVertsPerPoly];
for (int contourIndex = 0; contourIndex < contours.size(); ++contourIndex)
{
Contour contour = contours.get(contourIndex);
//4个数据一组，(x,y,z,regionID)，最少需要三个顶点
if (contour.verts.Length < 3 * 4)
{
Logger.LogError("[PolyMeshFieldBuilder][build]Bad Contour|{0}", contour.regionID);
continue;
}
//初始情况下，顶点索引对应的就是对应的顶点
/*
* Indices : 0 1 2 3 4 5 6 ....
* 0 1 2 3 4 5 6 ....
*/
workingIndices.Clear();
for (int i = 0; i < contour.vertCount; ++i) //这个顶点数是按四个一组的
{
workingIndices.Add(i);
} // for contour.vert
//三角剖分
int triangleCount = triangulate(contour.verts, ref workingIndices, ref workingTriangles);
if (triangleCount <= 0)
{
Logger.LogError("[PolyMeshField][build]Triangulate Contour|{0}", contour.regionID);
continue;
}
for (int iContourVert = 0; iContourVert < contour.vertCount; ++iContourVert)
{
int pContourVert = iContourVert * 4;
int vertHash = getHashCode(contour.verts[pContourVert],
contour.verts[pContourVert + 1],
contour.verts[pContourVert + 2]);
//vertIndices 里面储存的是根据顶点xyz hash出来的key，对应的在全局顶点表中的索引
//全局顶点表 以 xyz 3个为一组，储存轮廓的顶点
int iGlobalVert = 0;
if (!vertIndices.TryGetValue(vertHash, out iGlobalVert))
{
iGlobalVert = globalVertCount;
globalVertCount++;
vertIndices.Add(vertHash, iGlobalVert);
int newVertsBase = iGlobalVert * 3;
globalVerts[newVertsBase] = contour.verts[pContourVert];
globalVerts[newVertsBase + 1] = contour.verts[pContourVert + 1];
globalVerts[newVertsBase + 2] = contour.verts[pContourVert + 2];
}
//这个东东是临时用的，就是记录 轮廓中某个顶点的索引，对应的是在全局顶点表中索引
//Contour Vertex index -> global vertex index
contourToGlobalIndicesMap[iContourVert] = iGlobalVert;
} // for iContourVert
for (int i = 0; i < workingPolys.Length; ++i)
{
workingPolys[i] = PolyMeshField.NULL_INDEX;
} // for workingPolys
//只有这个阶段是三角形
workingPolyCount = 0;
for (int i = 0; i < triangleCount; ++i)
{
/*
* workingTraingles 储存的是上一步三角剖分的三角形的顶点索引
* ||
* V
* contourToGlobalIndicesMap 储存的是轮廓顶点索引，对应在全局顶点表的索引关系
* ||
* V
* workingPolys 中 储存的则是全局的顶点索引
*
*
*/
int polyIdxBase = workingPolyCount * mMaxVertsPerPoly;
int triangleIdxBase = i * 3;
workingPolys[polyIdxBase] =
contourToGlobalIndicesMap[workingTriangles[triangleIdxBase]];
workingPolys[polyIdxBase + 1] =
contourToGlobalIndicesMap[workingTriangles[triangleIdxBase + 1]];
workingPolys[polyIdxBase + 2] =
contourToGlobalIndicesMap[workingTriangles[triangleIdxBase] + 2];
workingPolyCount++;
} //triangleCount
//合并三角形
if (mMaxVertsPerPoly > 3)
{
while (true)
{
int longestMergeEdge = -1;
int pBestPolyA = -1;
int iPolyAVert = -1;
int pBestPolyB = -1;
int iPolyBVert = -1;
for (int iPolyA = 0; iPolyA < workingPolyCount - 1; ++iPolyA)
{
for (int iPolyB = iPolyA + 1; iPolyB < workingPolyCount; ++iPolyB)
{
//因为一个多边形最多有mMaxVertsPerPoly的点，所以
//多边形的真正起点为就是用多边形的索引乘以顶点数
//Can polyB merge with polyA?
getPolyMergeInfo(iPolyA * mMaxVertsPerPoly,
iPolyB * mMaxVertsPerPoly,
workingPolys,
globalVerts,
result.maxVertsPerPoly(),
out mergeInfo);
if (mergeInfo[0] > longestMergeEdge)
{
longestMergeEdge = mergeInfo[0];
pBestPolyA = iPolyA * mMaxVertsPerPoly;
iPolyAVert = mergeInfo[1];
pBestPolyB = iPolyB * mMaxVertsPerPoly;
iPolyBVert = mergeInfo[2];
}
} // for iPolyB
} // for iPolyA
if (longestMergeEdge <= 0)
{
break;
}
for (int i = 0; i < mergedPoly.Length; ++i)
{
mergedPoly[i] = PolyMeshField.NULL_INDEX;
}
int vertCountA = PolyMeshField.getPolyVertCount(pBestPolyA, workingPolys, result.maxVertsPerPoly());
int vertCountB = PolyMeshField.getPolyVertCount(pBestPolyB, workingPolys, result.maxVertsPerPoly());
int position = 0;
for (int i = 0; i < vertCountA - 1; ++i)
{
//pBestPolyA 为多边形对应的基索引
//iPolyAVert 为共享的一个端点
//+1 指的是共享点下一个顶点开始
int polyIdx = pBestPolyA + ((iPolyAVert + 1 + i) % vertCountA);
mergedPoly[position++] = workingPolys[polyIdx];
} // for vertCountA
for (int i = 0; i < vertCountB - 1; ++i)
{
int polyIdx = pBestPolyB + ((iPolyBVert + 1 + i) % vertCountB);
mergedPoly[position++] = workingPolys[polyIdx];
}
//将合并之后的顶点拷到A指定的多边形
Array.Copy(mergedPoly, 0, workingPolys, pBestPolyA, mMaxVertsPerPoly);
//将多边形B删除
Array.Copy(workingPolys, pBestPolyB + mMaxVertsPerPoly, workingPolys, pBestPolyB, workingPolys.Length - pBestPolyB - mMaxVertsPerPoly);
workingPolyCount--;
} // while true
} // if MaxVertsPerPoly
for (int i = 0; i < workingPolyCount; ++i)
{
Array.Copy(workingPolys, i * mMaxVertsPerPoly,
globalPolys, globalPolyCount * mMaxVertsPerPoly, mMaxVertsPerPoly);
globalRegions[globalPolyCount] = contour.regionID;
globalPolyCount++;
}
} // for contours
//xyz为一组
result.verts = new int[globalVertCount * 3];
Array.Copy(globalVerts, 0, result.verts, 0, globalVertCount * 3);
result.polys = new int[globalPolyCount * mMaxVertsPerPoly * 2];
for (int iPoly = 0; iPoly < globalPolyCount; ++iPoly)
{
int pPoly = iPoly * mMaxVertsPerPoly; //第几个Poly的索引
for (int offset = 0; offset < mMaxVertsPerPoly; ++offset)
{
//result里的多边形是以 2 * mMaxVertsPerPoly为一组的
//第一组 mMaxVertsPerPoly 是多边形自身的数据
//第二组 mMaxVertsPertPol 是邻接多边形的数据
//而globalPolys就是以一组 mMaxVertsPerPoly
result.polys[pPoly * 2 + offset] = globalPolys[pPoly + offset];
result.polys[pPoly * 2 + mMaxVertsPerPoly + offset] = PolyMeshField.NULL_INDEX;
}
} // for
result.polyRegions = new int[globalPolyCount];
Array.Copy(globalRegions, 0, result.polyRegions, 0, globalPolyCount);
buildAdjacencyData(result);
return(result);
} // build
