public void generateNeighborLinks(OpenHeightfield field)
        {
            if( field == null )
            {
                Logger.LogError("[OpenHeightfieldBuilder][generateNeighborLinks]field Empty"); 
                return; 
            }

            OpenHeightfield.OpenHeightFieldIterator iter = field.GetEnumerator(); 
            while( iter.MoveNext() )
            {
                OpenHeightSpan span = iter.Current; 
                for(int dir = 0; dir < 4; ++dir)
                {
                    //邻居的GirdIndex
                    int nWidthIndex = (iter.widthIndex() + BoundeField.getDirOffsetWidth(dir));
                    int nDepthIndex = (iter.depthIndex() + BoundeField.getDirOffsetDepth(dir)); 
                    
                    for(OpenHeightSpan nSpan = field.getData(nWidthIndex,nDepthIndex);
                        nSpan != null;
                        nSpan = nSpan.next())
                    {
                        int maxFloor = Math.Max(span.floor(), nSpan.floor());
                        int minCeling = Math.Min(span.ceiling(), nSpan.ceiling()); 

                        
                        if( (minCeling - maxFloor) >= mMinTraversableHeight   //邻居之间的通道足够高,可以通过 
                            && Math.Abs(nSpan.floor() - span.floor()) <= mMaxTraversableStep )  //两邻居之间的落差足够小
                        {
                            span.setNeighbor(dir, nSpan);
                            break; 
                        }
                    }

                }
            }
        }