public void printDistanceField()
{
Logger.Log("[OpenHeightfield][printDistanceField]Log Start");
Logger.Log("[OpenHeightfield][printDistanceField]Distance Field Spans|{0}", mSpanCount);
int depth = -1;
Logger.Log("\t");
for (int width = 0; width < this.width(); ++width)
{
Logger.Log("{0}\t", width);
}
OpenHeightFieldIterator iter = GetEnumerator();
while (iter.MoveNext())
{
OpenHeightSpan span = iter.Current;
if (iter.depthIndex() != depth)
{
Logger.LogWarning("\n{0}\t", ++depth);
}
Logger.Log("{0}\t", span.distanceToBorder());
}
Logger.Log("[OpenHeightfield][printDistanceField]Log End");
}
private void calcBorderDistanceBounds()
{
if (0 == mSpanCount)
{
return;
}
mMinBorderDistance = int.MaxValue;
mMaxBorderDistance = UNKNOWN;
OpenHeightFieldIterator iter = GetEnumerator();
while (iter.MoveNext())
{
OpenHeightSpan span = iter.Current;
mMinBorderDistance = Math.Min(mMinBorderDistance, span.distanceToBorder());
mMaxBorderDistance = Math.Max(mMaxBorderDistance, span.distanceToBorder());
}
if (mMinBorderDistance == int.MaxValue)
{
mMinBorderDistance = UNKNOWN;
}
}
/// <summary>
/// 必须nSpan是存在的，如果不存在的话，span2Border的值自然就0了
/// </summary>
/// <param name="span2Border"></param>
/// <param name="nSpan"></param>
/// <param name="isAxisNeighbor"></param>
/// <returns></returns>
private int calcMiniDistanceToBorder( int span2Border, OpenHeightSpan nSpan , bool isAxisNeighbor)
{
if( nSpan != null )
{
int nDist = nSpan.distanceToBorder();
if( nDist == NEEDS_INIT )
{
nDist = isAxisNeighbor ? 1 : 2;
}
else
{
nDist = isAxisNeighbor ? nDist + 2 : nDist + 3;
}
span2Border = Math.Min(span2Border, nDist);
}
else
{
Logger.LogWarning("[OpenHeightfieldBuilder][calcMiniDistanceToBorder]nSpan null");
}
return span2Border;
}
/* 参考 ：http://www.cnblogs.com/wantnon/p/4947067.html
* http://fab.cba.mit.edu/classes/S62.12/docs/Meijster_distance.pdf
* 具体算法名：Saito算法
* 因为初始化值都是未知的，通过一个大约估计的初始化，来重复来回算一个大致准确的距离
* 值 ？
*/
public void generateDistanceField(OpenHeightfield field)
{
if (field == null)
{
Logger.LogError("[OpenHeightfieldBuilder][generateNeighborLinks]field Empty");
return;
}
/*
* 先将OpenHeightField的Span数据转换成0和1的二值图。如果是边缘Span
* 那么就是0，否则就是NEEDS_INIT。
*/
OpenHeightfield.OpenHeightFieldIterator iter = field.GetEnumerator();
while( iter.MoveNext() )
{
OpenHeightSpan span = iter.Current;
bool isBorder = false;
for(int dir = 0; dir < 4; ++dir)
{
OpenHeightSpan nSpan = span.getNeighbor(dir);
if( null == nSpan
|| nSpan.getNeighbor(dir == 3 ? 0 : dir + 1) == null)
{
//如果8个邻居有任何一个缺失的话，那么就是边界Border
isBorder = true;
break;
}
}
if( isBorder )
{
//自己就是边界Border
span.setDistanceToBorder(BORDER);
}
else
{
//需要再次计算
span.setDistanceToBorder(NEEDS_INIT);
}
} //while
/*
* 逆时针访问？
*
* (-1,1) (0,1) (1,1)
* (-1,0) x (1,0)
* (-1,-1) (0,-1) (1,-1)
*/
//Pass 1
//顺序访问 (-1,0) (-1,-1) (0,-1) (1,-1)
iter.Reset();
while( iter.MoveNext() )
{
OpenHeightSpan span = iter.Current;
int selfDist = span.distanceToBorder();
if( selfDist == BORDER)
{
continue;
}
//(-1,0)
OpenHeightSpan nSpan = span.getNeighbor(0);
selfDist = calcMiniDistanceToBorder(selfDist, nSpan, true);
//(-1,-1),左下角的领域
nSpan = nSpan.getNeighbor(3); //领域0的领域3，也就是原Span的左下角
selfDist = calcMiniDistanceToBorder(selfDist, nSpan, false);
//(0,-1)
nSpan = span.getNeighbor(3);
selfDist = calcMiniDistanceToBorder(selfDist, nSpan, true);
//(1,-1)
nSpan = nSpan.getNeighbor(2);
selfDist = calcMiniDistanceToBorder(selfDist, nSpan, true);
span.setDistanceToBorder(selfDist);
} // while
//Pass 2
//顺序访问 (1,0) (1,1) (0,1) (-1,1)
//注意这个是反向遍历
iter.ReverseReset();
while( iter.MoveNext() )
{
OpenHeightSpan span = iter.Current;
int selfDist = span.distanceToBorder();
if( selfDist == BORDER )
{
continue;
}
/*
* 因为经过Pass1之后 ，所有的Span要么就是Border
* 要么就是有个大概值的，不会等于NEED_INIT的。
* 所以直接按照按照上面的流程跑
*/
//(1,0)
OpenHeightSpan nSpan = span.getNeighbor(2);
selfDist = calcMiniDistanceToBorder(selfDist, nSpan, true);
//(1,1)
nSpan = nSpan.getNeighbor(1);
selfDist = calcMiniDistanceToBorder(selfDist, nSpan, false);
//(0,1)
nSpan = span.getNeighbor(1);
selfDist = calcMiniDistanceToBorder(selfDist, nSpan, true);
//(-1,1)
nSpan = nSpan.getNeighbor(0);
selfDist = calcMiniDistanceToBorder(selfDist, nSpan, false);
span.setDistanceToBorder(selfDist);
}
field.clearBorderDistanceBounds();
}
public void blurDistanceField(OpenHeightfield field)
{
if( null == field )
{
return;
}
if( mSmoothingThreshold <= 0 )
{
return;
}
//Span => Distance
Dictionary<OpenHeightSpan, int> blurResults = new Dictionary<OpenHeightSpan, int>();
OpenHeightfield.OpenHeightFieldIterator iter = field.GetEnumerator();
while( iter.MoveNext() )
{
OpenHeightSpan span = iter.Current;
int origDist = span.distanceToBorder();
if( origDist <= mSmoothingThreshold ) //这里也会Border引进去
{
blurResults.Add(span, mSmoothingThreshold);
continue;
}
int workingDist = origDist;
//将9个格子的距离加起来
for(int dir = 0; dir < 4; ++dir)
{
OpenHeightSpan nSpan = span.getNeighbor(dir);
if( null == nSpan )
{
//这是不知道能不能看作自己占的比较增加了？但是为啥是 * 2 呢？
workingDist += origDist * 2;
}
else
{
workingDist += nSpan.distanceToBorder();
nSpan = nSpan.getNeighbor( (dir+1) & 0x3 ); //对角线的
if( null == nSpan )
{
workingDist += origDist;
}
else
{
workingDist += nSpan.distanceToBorder();
}
}
} //for
if( blurResults.ContainsKey(span) )
{
//除以9是平均呢，但是加上五就真的是不知道为什么了
blurResults[span] = (workingDist + 5) / 9;
}
} //while
//更新一下距离值
foreach( var blurIter in blurResults )
{
blurIter.Key.setDistanceToBorder(blurIter.Value);
}
}
private static bool floodNewRegion( OpenHeightSpan rootSpan,
int fillToDist ,
int regionID,
Stack<OpenHeightSpan> workingStack )
{
workingStack.Clear();
workingStack.Push(rootSpan);
rootSpan.setRegionID(regionID);
rootSpan.setDistanceToRegionCore(0);
int regionSize = 0;
//广度优先搜索
while( workingStack.Count > 0 )
{
OpenHeightSpan span = workingStack.Pop();
//表示当前Region是否已经在所属Region附近
bool isOnRegionBorder = false;
for( int dir = 0; dir < 4; ++dir )
{
OpenHeightSpan nSpan = span.getNeighbor(dir);
if( null == nSpan )
{
continue;
}
if( nSpan.regionID() != NULL_REGION
&& nSpan.regionID() != regionID )
{
isOnRegionBorder = true;
break;
}
//对角线邻居
nSpan = nSpan.getNeighbor((dir + 1) & 0x3);
if( nSpan != null
&& nSpan.regionID() != NULL_REGION
&& nSpan.regionID() != regionID )
{
isOnRegionBorder = true;
break;
}
} //for
//那么，它就不能成为新的Region
if( isOnRegionBorder )
{
span.setRegionID(NULL_REGION);
continue;
}
//到这里，表明要新增加一个Region了
regionSize++;
for( int dir = 0; dir < 4;++dir )
{
OpenHeightSpan nSpan = span.getNeighbor(dir);
if( nSpan != null
&& nSpan.distanceToBorder() >= fillToDist //
&& nSpan.regionID() == NULL_REGION )
{
nSpan.setRegionID(regionID);
nSpan.setDistanceToRegionCore(0); //如果是同一区域的话 ？离中心是0的？
workingStack.Push(nSpan);
}
}
} // while
return regionSize > 0;
}
public void generateRegions( OpenHeightfield field )
{
if (null == field)
{
return;
}
//这个距离，控制生成的网络有多贴近实际的模型
int minDist = mTraversableAreaBorderSize + field.minBorderDistance();
int expandIterations = 4 + (mTraversableAreaBorderSize * 2); //TODO emmm
//排除奇数
int dist = (field.maxBorderDistance() - 1) & ~1 ;
List<OpenHeightSpan> floodedSpans = new List<OpenHeightSpan>(1024);
Stack<OpenHeightSpan> workingStack = new Stack<OpenHeightSpan>(1024);
OpenHeightfield.OpenHeightFieldIterator iter = field.GetEnumerator();
int nextRegionID = 1;
//高于这个距离的体素都得生成Regions，那剩下的体素怎么办呢？
while ( dist > minDist )
{
iter.Reset();
floodedSpans.Clear();
while( iter.MoveNext() )
{
OpenHeightSpan span = iter.Current;
if( span.regionID() == NULL_REGION
&& span.distanceToBorder() >= dist )
{
floodedSpans.Add(span);
}
}
if( nextRegionID > 1 )
{
//大于1表示已经至少存在1个region，先去尝试一下合并
if( dist > 0 )
{
expandRegions(floodedSpans, expandIterations);
}
else //这里不太可能会走到吧？除非minDist == 0
{
expandRegions(floodedSpans, -1);
}
}
//剩下的可能要生成新的Region
foreach( OpenHeightSpan span in floodedSpans )
{
if( null == span
|| span.regionID() != NULL_REGION )
{
continue;
}
//TODO ????
int fillTo = Math.Max(dist - 2, minDist);
if( floodNewRegion(span,fillTo,nextRegionID,workingStack ))
{
nextRegionID++;
}
}
//更新深度
dist = Math.Max(dist - 2, 0);
} //while dist > minDist
//最后一篇循环
iter.Reset();
floodedSpans.Clear();
while( iter.MoveNext() )
{
OpenHeightSpan span = iter.Current;
if( span.distanceToBorder() >= minDist
&& span.regionID() == NULL_REGION )
{
floodedSpans.Add(span);
}
}
if( minDist > 0 )
{
expandRegions(floodedSpans, expandIterations * 8);
}
else
{
expandRegions(floodedSpans, -1);
}
field.setRegionCount(nextRegionID);
//后处理
foreach( IOpenHeightFieldAlgorithm algorithm in mRegionAlgorithms )
{
algorithm.apply(field);
}
}