inline bool CAccessDistancePathVerifier::_IsBlock(unsigned int uiGridInfo)
{
	return (uiGridInfo & (1<<20)) && (uiGridInfo & (1<<21));
}
//------------------------------------------------------------------------------
inline int CAccessDistancePathVerifier::_GridPos2ID(int iX, int iY)
{
	if (iX<0 || iX>=m_iSizeX || iY<0 ||iY>=m_iSizeY) return -1;

	return (iY*m_iSizeX + iX);
}
//------------------------------------------------------------------------------
inline void CAccessDistancePathVerifier::_Swap(int& i, int& k)
{
	int tmp = i;
	i = k;
	k = tmp;
}
//------------------------------------------------------------------------------
inline float CAccessDistancePathVerifier::_DDAGetAccessDistance(
						int iStartX, int iStartY, int k, unsigned int** ppuiMapInfo)
{
	float fdx = m_arrDx[k];
	float fdy = m_arrDy[k];

	float fCurrX = iStartX;
	float fCurrY = iStartY;

	while (fCurrX<=m_iSizeX && fCurrY<=m_iSizeY)
	{
		if (_IsBlock(ppuiMapInfo[((int)fCurrY)][(int)fCurrX]))
		{
			// 找到这个方向第一个不可通行点
			break;
		}

		// 步进
		fCurrX += fdx;
		fCurrY += fdy;
	}

	return sqrt((fCurrX-iStartX)*(fCurrX-iStartX) + (fCurrY-iStartY)*(fCurrY-iStartY));
}
//------------------------------------------------------------------------------
inline float CAccessDistancePathVerifier::_GetMaxAccessAround(
				int iX, int iY, float** ppRealAccDist, int iDir)
{
	float fMaxDist = _GetAccessDistance(iX, iY, ppRealAccDist, iDir);

	float fNeighborAcc = _GetAccessDistance(iX-1, iY, ppRealAccDist, iDir);
	//if (fNeighborAcc > 0.0f)
	//{
	//	fNeighborAcc = __max(fNeighborAcc,  _GetAccessDistance(iX-2, iY, ppRealAccDist, iDir));
	//}
	fMaxDist = __max(fMaxDist, fNeighborAcc);

	fNeighborAcc = _GetAccessDistance(iX+1, iY, ppRealAccDist, iDir);
	//if (fNeighborAcc > 0.0f)
	//{
	//	fNeighborAcc = __max(fNeighborAcc,  _GetAccessDistance(iX+2, iY, ppRealAccDist, iDir));
	//}
	fMaxDist = __max(fMaxDist, fNeighborAcc);
	
	fNeighborAcc = _GetAccessDistance(iX, iY-1, ppRealAccDist, iDir);
	//if (fNeighborAcc > 0.0f)
	//{
	//	fNeighborAcc = __max(fNeighborAcc,  _GetAccessDistance(iX, iY-2, ppRealAccDist, iDir));
	//}
	fMaxDist = __max(fMaxDist, fNeighborAcc);

	fNeighborAcc = _GetAccessDistance(iX, iY+1, ppRealAccDist, iDir);
	//if (fNeighborAcc > 0.0f)
	//{
	//	fNeighborAcc = __max(fNeighborAcc,  _GetAccessDistance(iX, iY+2, ppRealAccDist, iDir));
	//}
	fMaxDist = __max(fMaxDist, fNeighborAcc);


	return fMaxDist;
}
//------------------------------------------------------------------------------
inline float  CAccessDistancePathVerifier::_GetAccessDistance(
	int iX, int iY, float** ppRealAccDist, int iDir)
{
	assert(iDir <= NUM_AROUND_DIRECTIONS);

	if (iX<0 || iX>=m_iSizeX || iY<0 || iY>m_iSizeY) return 0.0f;

	int iGridID = iY*m_iSizeX + iX;

	return (ppRealAccDist[iGridID]==0) ? 0.0f : (ppRealAccDist[iGridID][iDir]);
}
//------------------------------------------------------------------------------
inline bool CAccessDistancePathVerifier::VerifiyWalkable(
	int iStartX, int iStartY, int iEndX, int iEndY)
{
	// y 小的为 start, 大的为 end
	if (iStartY > iEndY)
	{
		_Swap(iStartX, iEndX);
		_Swap(iStartY, iEndY);
	}

	int iDX = iEndX - iStartX;
	int iDY = iEndY - iStartY;

	// 根据斜率计算角度
	float fSlop = (float)(iDY) / (float)(iDX);
	float fAngle = atan(fSlop); // 弧度
	if (iDX < 0) {fAngle += M_PI;}

	// 判断 fAngle 落在哪个区间
	int k = (fAngle + m_fHalfDAngle) / m_fDAngle;

	// 从表中查询在 k 方向所能到达的距离
	int iHalfGridID = ((iStartY>>1)*m_iHalfSizeX) + (iStartX>>1);
	if (m_ucAccessDistance[iHalfGridID] == 0) 
	{
		// 该点不可行走
		return false;
	}

	int iAccDist = 
		m_ucAccessDistance[iHalfGridID][k];

	// 用距离平方比较
	return ((iAccDist*iAccDist)<<2) >= (iDX*iDX + iDY*iDY);
}