LOD 地形渲染有关问题

LOD 地形渲染问题
LOD学习有一周了，有一些突破，还是有BUG，不知道怎么解决，下面是效果图：


这里只是先修补上方点，加了俩条边！


这里多了很多莫名的边，不知道原因.

下面给出顶点添加的代码：
void GameLodTerrain::SetNodeVertex(QuadTreeNode *pNode)
{
   
  if(pNode->m_Size<2||pNode==NULL) return;
  if (FALSE == pNode->m_bIsVisible||FALSE==pNode->m_bIsTouched)
  return;
  if (TRUE == pNode->m_bIsReached)
  {
  // fill vertex buffer
  static INT nSizeDivide2 = m_row >> 1;
  INT L = pNode->m_CenterX - (pNode->m_Size >> 1); // left
  INT R = pNode->m_CenterX + (pNode->m_Size >> 1); // right
  INT X = pNode->m_CenterX; // center X
  INT Y = pNode->m_CenterY; // center Y
  INT T = pNode->m_CenterY - (pNode->m_Size >> 1); // top
  INT B = pNode->m_CenterY + (pNode->m_Size >> 1); // bottom

  INT L1=0;INT R1=0;INT T1=0;INT B1=0;
  if(!pNode->m_bIsLeaf&&pNode->m_Size<=4)
  {
  L1 = pNode->m_CenterX - (pNode->m_Size >> 2); // left
  R1 = pNode->m_CenterX + (pNode->m_Size >> 2); // right
  T1 = pNode->m_CenterY - (pNode->m_Size >> 2); // top
  B1 = pNode->m_CenterY + (pNode->m_Size >> 2); // bottom
  }

  // 1 2 3 TL Top TR
  // 8 0 4 -> Left Center Right
  // 7 6 5 BL Bottom BR
  int i=0;
  // CENTER
  m_pVerticesPtr[m_vbIndex + i]._x = (X - nSizeDivide2) * m_wScale;
  m_pVerticesPtr[m_vbIndex + i]._z = (Y - nSizeDivide2) * m_wScale;
  m_pVerticesPtr[m_vbIndex + i]._y = m_heightmap[Y][X];
  m_pVerticesPtr[m_vbIndex + i]._u = m_tuArray[X];
  m_pVerticesPtr[m_vbIndex + i]._v = m_tvArray[Y];
  i++;
  // TL
  m_pVerticesPtr[m_vbIndex + i]._x = (L - nSizeDivide2) * m_wScale;
  m_pVerticesPtr[m_vbIndex + i]._z = (T - nSizeDivide2) * m_wScale;
  m_pVerticesPtr[m_vbIndex + i]._y = m_heightmap[T][L];
  m_pVerticesPtr[m_vbIndex + i]._u = m_tuArray[L];
  m_pVerticesPtr[m_vbIndex + i]._v = m_tvArray[T];
  i++;
  // TOP,上方要进行修补处理
  QuadTreeNode *n=FindNode(X,Y-pNode->m_Size);
  if(pNode->m_bIsLeaf||n==NULL)
  {
  m_pVerticesPtr[m_vbIndex + i]._x = (X - nSizeDivide2) * m_wScale;
  m_pVerticesPtr[m_vbIndex + i]._z = (T - nSizeDivide2) * m_wScale;
  m_pVerticesPtr[m_vbIndex + i]._u = m_tuArray[X];
  m_pVerticesPtr[m_vbIndex + i]._v = m_tvArray[T];
  m_pVerticesPtr[m_vbIndex + i]._y = m_heightmap[T][X];
  i++; 
  }
  else if(n->m_Size>4||n->m_bIsReached||!n->m_bIsTouched)
  {

  m_pVerticesPtr[m_vbIndex + i]._x = (X - nSizeDivide2) * m_wScale;
  m_pVerticesPtr[m_vbIndex + i]._z = (T - nSizeDivide2) * m_wScale;
  m_pVerticesPtr[m_vbIndex + i]._u = m_tuArray[X];
  m_pVerticesPtr[m_vbIndex + i]._v = m_tvArray[T];
  m_pVerticesPtr[m_vbIndex + i]._y = m_heightmap[T][X];
  i++; 
  }
  else if(!n->m_bIsReached&&n->m_Size<=4)
  {
  m_pVerticesPtr[m_vbIndex + i]._x = (L1 - nSizeDivide2) * m_wScale;
  m_pVerticesPtr[m_vbIndex + i]._z = (T - nSizeDivide2) * m_wScale;