Neighbor class and disconnected polygons

Helper

THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

On 03/08/2012 at 10:33, xxxxxxxx wrote:

Just for completeness, here is the latest in-use code...

  
class ConnectedPolyGroup  
{  
private:  
  Bool        m_bInit;  
  LONG        m_numVerts;  
  LONG        m_numPolys;  
  LONG        m_numMappedPolys;  
  LONG        m_GroupCount;  
  CPolygon    *m_pDstPolys;  
  UCHAR        *m_pDstPolyProcessed;  
  UCHAR        *m_pNeighborsAdded;  
  LONG        *m_pGroupIDs;  
  Neighbor    m_dstNbr;  
  
  Bool ProccessConnectedPolys(void);  
public:  
  void FreeData(void);  
  BaseSelect *SelectGroup(LONG GroupID);  
  LONG NumPolys(void)                        { return m_numPolys; }  
  LONG NumConnectedGroups(void)            { return m_GroupCount; }  
  LONG GroupID(LONG polyNdx)                { if(!m_bInit || polyNdx >= m_numPolys) return NOTOK;    return  m_pGroupIDs[polyNdx]; }  
  Bool Init(PolygonObject *pPolyObj);  
  
  ConnectedPolyGroup(void);  
  ~ConnectedPolyGroup(void);  
};  
  
ConnectedPolyGroup::ConnectedPolyGroup(void)  
{  
  m_bInit = false;  
  m_GroupCount = 0;  
  m_pDstPolyProcessed = NULL;  
  m_pNeighborsAdded = NULL;  
  m_pGroupIDs = NULL;  
}  
  
ConnectedPolyGroup::~ConnectedPolyGroup(void)  
{  
  this->FreeData();  
}  
  
void ConnectedPolyGroup::FreeData(void)  
{  
  bDelete(m_pDstPolyProcessed);  
  bDelete(m_pNeighborsAdded);  
  bDelete(m_pGroupIDs);  
  m_numMappedPolys = 0;  
  m_GroupCount = 0;  
  m_numVerts = 0;  
  m_numPolys = 0;  
  m_bInit = false;  
}  
  
// generate a BaseSelect based on connected GroupID - caller owns returned BaseSelect pointer  
BaseSelect *ConnectedPolyGroup::SelectGroup(LONG GroupID)  
{  
  if(!m_bInit || GroupID >= m_GroupCount)    return NULL;  
  
  BaseSelect *pSel = BaseSelect::Alloc();  
  if( !pSel )                                return NULL;  
  pSel->DeselectAll();    // <-- shouldn't actually be needed  
  
  LONG polyNdx;  
  for(polyNdx=0; polyNdx<m_numPolys; polyNdx++)  
  {  
      if( m_pGroupIDs[polyNdx] == GroupID )  
          pSel->Select(polyNdx);  
  }  
  return pSel;  
}  
  
Bool ConnectedPolyGroup::Init(PolygonObject *pPolyObj)  
{  
  this->FreeData();  
  
  m_numVerts = pPolyObj->GetPointCount();  
  m_numPolys = pPolyObj->GetPolygonCount();  
  m_pDstPolys = pPolyObj->GetPolygonW();  
  
  // track which polys have been processed.  
  m_pDstPolyProcessed = bNew UCHAR[m_numPolys];  
  if( !m_pDstPolyProcessed )        return false;  
  
  // track which polys have had their neighbors added.  
  m_pNeighborsAdded = bNew UCHAR[m_numPolys];  
  if( !m_pNeighborsAdded )        return false;  
  
  // track which 'connected group' each poly belongs to  
  m_pGroupIDs = bNew LONG[m_numPolys];  
  if( !m_pGroupIDs )                return false;  
  
  // initialize Neighbor class  
  if( !m_dstNbr.Init(m_numVerts, m_pDstPolys, m_numPolys, NULL) )    return false;  
  
  ClearMem(m_pDstPolyProcessed, m_numPolys * sizeof(UCHAR), 0);  
  ClearMem(m_pNeighborsAdded, m_numPolys * sizeof(UCHAR), 0);  
  ClearMem(m_pGroupIDs, m_numPolys * sizeof(LONG), 0);  
  
  LONG polyNdx;  
  Bool done = false;  
  for(polyNdx=0; polyNdx<m_numPolys; polyNdx++)  
  {  
      if( m_pDstPolyProcessed[polyNdx] )    continue;  
  
      m_pGroupIDs[polyNdx] = m_GroupCount;                        // set group index/ID  
      m_pDstPolyProcessed[polyNdx] = 1;                            // mark this one off...  
      m_numMappedPolys++;  
  
      done = this->ProccessConnectedPolys();                        // set all neighbors to same group index/ID  
  
      m_GroupCount++;                                                // bump group index/ID for next group  
      if( done )    break;  
  }  
  
  // done with these...  
  bDelete(m_pDstPolyProcessed);  
  bDelete(m_pNeighborsAdded);  
  m_bInit = true;  
  return true;  
}  
  
Bool ConnectedPolyGroup::ProccessConnectedPolys(void)  
{  
  Bool morePolys = true;  
  while( morePolys )  
  {  
      morePolys = false;  
      LONG polyNdx;  
      for(polyNdx=0; polyNdx<m_numPolys; polyNdx++)  
      {  
          if( !m_pDstPolyProcessed[polyNdx] )    continue;    // only adding/processing neighbors of previously matched/valid polys  
          if( m_pNeighborsAdded[polyNdx] )    continue;    // don't add/process neighbors if already added  
  
//            CPolygon *pDstPoly = &m_pDstPolys[polyNdx];  
          PolyInfo *pDstPolyInfo = m_dstNbr.GetPolyInfo(polyNdx);  
          LONG side;  
          for(side=0; side<4; side++)  
          {  
                  LONG dstNbrNdx = pDstPolyInfo->face[side];  
              if( dstNbrNdx == NOTOK )                continue;    // skip any sides that don't exist  
              if( m_pDstPolyProcessed[dstNbrNdx] )    continue;    // only adding neighbors not already added  
  
              m_pGroupIDs[dstNbrNdx] = m_GroupCount;        // all connected polys get the same index/ID  
              m_pDstPolyProcessed[dstNbrNdx] = 1;            // mark this one off...  
              m_numMappedPolys++;  
              morePolys = true;                            // since we added / processed another poly, make sure we loop again to get _it's_ neighbors  
          }  
          m_pNeighborsAdded[polyNdx] = 1;                    // we've processed this polys neighbors  
  
          if( m_numMappedPolys == m_numPolys )  
          {  
              morePolys = false;  
              break;    // return true?  
          }  
      }  
  }  
  if( m_numMappedPolys == m_numPolys )  
      return true;  
  return false;  
}

...I _think_ the only difference in that and what's posted above is that I go ahead and free a couple (no-longer-needed) arrays inside Init() instead of waiting for the Destructor.

As an aside, based on some later use of this base code (in this thread), I think that I determined that I didn't really need the m_pNeighborsAdded array/checking/tracking at all.

Helper

THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

On 04/08/2012 at 07:55, xxxxxxxx wrote:

Will compare code and update as needed. Thanks!