} //buildRawContour
/*
* 以Span为s ， direction 为 0 举例，这个函数要寻找的就是s,ds,ns,里面，floor最大值
* ds
* ns s
*
* 如果direction为1的话
* ns ds
* s
*
*/
private static int getCornerHeight(OpenHeightSpan span, int direction)
{
//OpenHeightSpan的floor 就真的是floor了，而不是
//像 SolidHeightSpan那样对应的其实是顶部
int maxFloor = span.floor();
OpenHeightSpan dSpan = null;
//顺时针
int directionOffset = NMGenUtility.ClockwiseRotateDir(direction);
OpenHeightSpan nSpan = span.getNeighbor(direction);
if (nSpan != null)
{
maxFloor = Math.Max(maxFloor, nSpan.floor());
dSpan = nSpan.getNeighbor(directionOffset);
}
nSpan = span.getNeighbor(directionOffset);
if (nSpan != null)
{
maxFloor = Math.Max(maxFloor, nSpan.floor());
if (null == dSpan)
{
dSpan = nSpan.getNeighbor(direction);
}
}
if (dSpan != null)
{
maxFloor = Math.Max(maxFloor, dSpan.floor());
}
return(maxFloor);
}
/// <summary>
/// </summary>
/// <param name="startSpan"></param>
/// <param name="borderDirection"></param>
/// <param name="newRegionID"></param>
private void partialFloodRegion(OpenHeightSpan startSpan,
int borderDirection,
int newRegionID)
{
int antiBorderDirection = NMGenUtility.AntiDir(borderDirection);
int regionID = startSpan.regionID();
startSpan.setRegionID(newRegionID);
startSpan.setDistanceToRegionCore(0); //???所以这个值 没啥卵用啊，一直都是0的
mwOpenSpans.Push(startSpan);
mwBorderDistance.Push(0);
while (mwOpenSpans.Count > 0)
{
OpenHeightSpan span = mwOpenSpans.Pop();
int distance = mwBorderDistance.Pop();
for (int i = 0; i < 4; ++i)
{
OpenHeightSpan nSpan = span.getNeighbor(i);
if (null == nSpan ||
nSpan.regionID() != regionID)
{
continue;
}
int nDistance = distance;
if (i == borderDirection) //null region所在的方向
{
//这里是不是应该小于等于0呢？
// 以这个距离Border为0作为边界，将大于0那一侧的Span全部变成
// 新的Region。然后小于等于0那一侧的作为旧的Region保留下来。
if (0 == distance)
{
continue;
}
nDistance--;
}
else if (i == antiBorderDirection)
{
nDistance++;
}
//注意上面的if-else，如果都不是这两个方向的Span
//会直接被重新设置为新的Region
nSpan.setRegionID(newRegionID);
nSpan.setDistanceToRegionCore(0);
mwOpenSpans.Push(nSpan);
mwBorderDistance.Push(nDistance);
}
}
}
/// <summary>
/// 重新设置对应的Region，根据拐点的情况
/// </summary>
/// <param name="referenceSpan"></param>
/// <param name="borderDirection"></param>
/// <param name="cornerDirection"></param>
/// <returns></returns>
private int selectedRegionID(OpenHeightSpan referenceSpan,
int borderDirection,
int cornerDirection)
{
referenceSpan.getDetailedRegionMap(ref mwNeighborRegions, 0);
/*
* Initial example state:
*
* a - Known region.
* x - Null region.
* u - Unknown, not checked yet.
*
* u u u
* u a x
* u a a
*/
int antiBorderDirection = NMGenUtility.AntiDir(borderDirection);
int antiCornerDirection = NMGenUtility.AntiDir(cornerDirection);
int regionID = mwNeighborRegions[antiBorderDirection];
if (regionID == referenceSpan.regionID() ||
NULL_REGION == regionID)
{
/*
* The region away from the border is either a null region
* or the same region. So we keep the current region.
*
* u u u u u u
* a a x or x a x <-- Potentially bad, but stuck with it.
* u a a u a a
*/
return(referenceSpan.regionID());
}
int potentialRegion = regionID;
regionID = mwNeighborRegions[antiCornerDirection];
if (regionID == referenceSpan.regionID() ||
NULL_REGION == regionID)
{
/*
* The region opposite from the corner direction is
* either a null region or the same region. So we
* keep the current region.
*
* u a u u x u
* b a x or b a x
* u a a u a a
*/
return(referenceSpan.regionID());
}
int potentialCount = 0;
int currentCount = 0;
for (int i = 0; i < 8; ++i)
{
if (mwNeighborRegions[i] == referenceSpan.regionID())
{
currentCount++;
}
else if (mwNeighborRegions[i] == potentialRegion)
{
potentialCount++;
}
}
return(potentialCount < currentCount
? referenceSpan.regionID()
: potentialRegion);
}
public void apply(OpenHeightfield field)
{
if (null == field)
{
Logger.LogError("[CLeanNullRegionBorders][apply]field null");
return;
}
int nextRegionID = field.regionCount();
OpenHeightfield.OpenHeightFieldIterator iter = field.GetEnumerator();
while (iter.MoveNext())
{
OpenHeightSpan span = iter.Current;
if (span.flags != 0)
{
continue;
}
span.flags = 1;
OpenHeightSpan workingSpan = null;
int edgeDirection = -1;
if (NULL_REGION == span.regionID())
{
//找到Border Span第一个非空的邻居
edgeDirection = getNonNullBorderDrection(span);
if (-1 == edgeDirection)
{
continue;
}
//起点Span为有所属Region的Span
//而行走方向为 null Region所在的方向
workingSpan = span.getNeighbor(edgeDirection);
//转180度
edgeDirection = NMGenUtility.AntiDir(edgeDirection);
}
else if (!mUseOnlyNullSpans)
{
//起点Span为 null Region的Span
//而行走方向即为有所属 Region 的 Span
edgeDirection = getNullBorderDrection(span);
if (-1 == edgeDirection)
{
continue;
}
workingSpan = span;
}
else
{
continue;
}
//上面两个分支都会保证workingSpan是有所属Region的
//而Dir 即是 Region 为 Null Region的Dir
bool isEncompassedNullRegion = processNullRegion(workingSpan, edgeDirection);
if (isEncompassedNullRegion) //确定以这个Span为起点的Region，是一个单一Region，并且内含了一个Null Region
{
//如果是完全包含了不可走的NullRegion ，就将这个Region分割成两个Region
partialFloodRegion(workingSpan, edgeDirection, nextRegionID);
nextRegionID++;
}
}
field.setRegionCount(nextRegionID);
iter.Reset();
while (iter.MoveNext())
{
iter.Current.flags = 0;
}
}
/// <summary>
/// 为了防止 Null Region 内含在有效Region内，这阻碍了凸包的生成
/// </summary>
/// <param name="startSpan"></param>
/// <param name="startDirection"></param>
/// <returns></returns>
private bool processNullRegion(OpenHeightSpan startSpan, int startDirection)
{
/*
* 这段直接翻译源码的：
* 这个算法遍历这个轮廓。正如它所做的，这个算法检测并且修复一些危险的
* Span Configurations。
*
* 遍历轮廓：一个很好的可视化方向就是，想像一个机器人面向一堵墙，并坐
* 在地板上。它会采取以下措施来绕过这堵墙：
* 1. 如果有一堵墙位于它的前面，顺时针转90度，直到他前面不再是墙。
* 2. 向前一步。
* 3. 逆时针转向90度
* 4. 重复从1开始的步骤 ，直到它发现自己位于原来的起点，还有原来的朝向。
*
*/
/*
* 算法在遍历的同时，检测锐角(90度) 和 钝角(270)拐点。如果
* 一个完整的轮廓被检测完整，并且 钝角拐点比锐角拐点多。那
* 么 null Region 就在这个轮廓里面。否则就在轮廓外面。
*
*/
//环绕null region 走一圈，最后走回自己的起点
int borderRegionID = startSpan.regionID();
OpenHeightSpan span = startSpan;
OpenHeightSpan nSpan = null;
int dir = startDirection;
int loopCount = 0;
int acuteCornerCount = 0;
int obtuseCornerCount = 0;
int stepsWithoutBorder = 0;
bool borderSeenLastLoop = false;
bool isBorder = true;
bool hasSingleConnection = true;
while (++loopCount < int.MaxValue)
{
//初始方向就是面向的Null Region，所以一开始是肯定是isBorder的
nSpan = span.getNeighbor(dir);
if (null == nSpan)
{
isBorder = true;
}
else
{
nSpan.flags = 1;
if (NULL_REGION == nSpan.regionID())
{
isBorder = true;
}
else
{
isBorder = false;
if (nSpan.regionID() != borderRegionID)
{
hasSingleConnection = false;
}
}
} // else
if (isBorder)
{
if (borderSeenLastLoop)
{
/*
* a x
* x x
*/
//其实这个应用用inner来描述更加准确 ，表明a被x包围了
acuteCornerCount++;
}
else if (stepsWithoutBorder > 1)
{
/*
* a a
* a x
*
*/
obtuseCornerCount++; //相对地，我觉得这个应该用outer来描述更加准确，表明a正在包围x
stepsWithoutBorder = 0;
//处理钝角的各种异常情况
if (processOuterCorner(span, dir))
{
hasSingleConnection = false;
}
}
dir = NMGenUtility.ClockwiseRotateDir(dir);
borderSeenLastLoop = true;
stepsWithoutBorder = 0;
}
else //注意，不是边界，才会进行移动，如果是边界的话，只会进行转向
{
span = nSpan;
dir = NMGenUtility.CClockwiseRotateDir(dir); //逆时针转向一下
borderSeenLastLoop = false;
stepsWithoutBorder++;
} // else
//回到原方位了
if (startSpan == span &&
startDirection == dir)
{
return(hasSingleConnection &&
obtuseCornerCount > acuteCornerCount);
}
} // while
return(false);
}
//遍历轮廓，找邻接的Region
private static void findRegionConnections(OpenHeightSpan startSpan,
int startDirection,
ref List <int> outConnections)
{
OpenHeightSpan span = startSpan;
int dir = startDirection;
int lastEdgeRegionID = NULL_REGION;
OpenHeightSpan nSpan = span.getNeighbor(dir);
if (nSpan != null)
{
lastEdgeRegionID = nSpan.regionID();
}
//连接的Region，至少存在一个NULL_REGION
outConnections.Add(lastEdgeRegionID);
int loopCount = 0;
while (++loopCount < ushort.MaxValue)
{
nSpan = span.getNeighbor(dir);
int currEdgeRegionID = NULL_REGION; //默认nSpan是null的
if (null == nSpan ||
nSpan.regionID() != span.regionID())
{
if (nSpan != null)
{
currEdgeRegionID = nSpan.regionID();
}
if (currEdgeRegionID != lastEdgeRegionID)
{
outConnections.Add(currEdgeRegionID);
lastEdgeRegionID = currEdgeRegionID;
}
//顺时针转向下一个
dir = NMGenUtility.ClockwiseRotateDir(dir);
}
else
{
//这个分支代表 Region是相同的
span = nSpan;
//逆时针转一下
dir = NMGenUtility.CClockwiseRotateDir(dir);
}
if (startSpan == span &&
startDirection == dir)
{
break;
}
} //while
//TODO 为啥会存在首尾相同呢？因为退出条件是原来的那个点么
int connectionsCnt = outConnections.Count;
if (connectionsCnt > 1 &&
outConnections[0] == outConnections[connectionsCnt - 1])
{
outConnections.RemoveAt(connectionsCnt - 1);
}
}
private void buildRawContours(OpenHeightSpan startSpan,
int startWidthIndex,
int startDepthIndex,
int startDirection,
ref List <int> outContourVerts
)
{
OpenHeightSpan span = startSpan;
int dir = startDirection;
int spanX = startWidthIndex;
int spanZ = startDepthIndex;
int loopCount = 0;
while (++loopCount < ushort.MaxValue)
{
//这个Edge的一个Span
if (!isSameRegion(span, dir))
{
//span
int px = spanX;
int py = getCornerHeight(span, dir);
int pz = spanZ;
/*
* 这里取的是点，所以需要做这些偏移来记录点，而不是记录对应的Span
* 这里需要结合 ： 方向 + 某个点 ，来理解 为什么要加这个偏移
*
*
* * --- *
* | S |
* ----—-*
*
* dir = 0 的时候，需要取左上角的点
* dir = 1 的时候，需要取右上角的点
* dir = 2 的时候，需要取右下角的点
* dir = 3 的时候，取的就是参考点
*
* 以左下角的点为参考点，就是 dir方向对应的顺时针的点
*
*/
/*
* Update the px and pz values based on current direction.
* The update is such that the corner being represented is
* clockwise from the edge the direction is currently pointing
* toward.
*/
switch (dir)
{
case 0: pz++; break;
case 1: px++; pz++; break;
case 2: px++; break;
}
int regionThisDirection = NULL_REGION;
OpenHeightSpan nSpan = span.getNeighbor(dir);
if (nSpan != null)
{
regionThisDirection = nSpan.regionID();
}
//这是轮廓的点
outContourVerts.Add(px);
outContourVerts.Add(py);
outContourVerts.Add(pz);
outContourVerts.Add(regionThisDirection);
span.flags &= ~(1 << dir); //清除dir对应的位
dir = NMGenUtility.ClockwiseRotateDir(dir);
} //isSameRegion
else
{
//这段就是步进到下一个同Region的Span，很好理解。
span = span.getNeighbor(dir);
switch (dir)
{
case 0: spanX--; break;
case 1: spanZ++; break;
case 2: spanX++; break;
case 3: spanZ--; break;
}
dir = NMGenUtility.CClockwiseRotateDir(dir);
} // no the SameRegion
if (span == startSpan &&
dir == startDirection)
{
break;
}
} //while
} //buildRawContour