Ojectarx之无序点集逆时针排序

//若点a大于点b,即点a在点b顺时针方向,返回true,否则返回false
bool PointCmp(AcGePoint2d& a,AcGePoint2d& b,AcGePoint2d& center)
{
if (a.x >= 0 && b.x < 0)
return true;
if (a.x == 0 && b.x == 0)
return a.y > b.y;
//向量OA和向量OB的叉积
int det = (a.x - center.x) * (b.y - center.y) - (b.x - center.x) * (a.y - center.y);
if (det < 0)
return true;
if (det > 0)
return false;
//向量OA和向量OB共线，以距离判断大小
int d1 = (a.x - center.x) * (a.x - center.x) + (a.y - center.y) * (a.y - center.y);
int d2 = (b.x - center.x) * (b.x - center.y) + (b.y - center.y) * (b.y - center.y);
return d1 > d2;
}
void CCommonFunction::ClockwiseSortPoints(AcGePoint2dArray &vPoints)
{
//计算重心
AcGePoint2d centerstruct;
double x = 0,y = 0;
for (int i = 0;i < vPoints.length();i++)
{
x += vPoints[i].x;
y += vPoints[i].y;
}
centerstruct.x = x/vPoints.length();
centerstruct.y = y/vPoints.length();

//冒泡排序
for(int i = 0;i < vPoints.length() - 1;i++)
{
for (int j = 0;j < vPoints.length() - i - 1;j++)
{
if (PointCmp(vPoints[j],vPoints[j+1],centerstruct))
{
AcGePoint2d tmp = vPoints[j];
vPoints[j] = vPoints[j + 1];
vPoints[j + 1] = tmp;
}
}
}
}