int mglnrel::ptInArea(
const Point2d& pt, int count, const Point2d* pts,
int& order, const Tol& tol, bool closed)
{
int i;
int odd = 1; // 1: 交点数为偶数, 0: 交点数为奇数
float minDist = tol.equalPoint();
Point2d nearpt;
order = -1;
for (i = 0; i < count && tol.equalPoint() < 1.e5f; i++)
{
// P与某顶点重合. 返回 kPtAtVertex, order = 顶点号 [0, count-1]
float d = pt.distanceTo(pts[i]);
if (minDist > d) {
minDist = d;
order = i;
}
}
if (order >= 0) {
return kPtAtVertex;
}
order = -1;
minDist = tol.equalPoint();
for (i = 0; i < (closed ? count : count - 1); i++)
{
const Point2d& p1 = pts[i];
const Point2d& p2 = (i+1 < count) ? pts[i+1] : pts[0];
// P在某条边上. 返回 kPtOnEdge, order = 边号 [0, count-1]
float d = mglnrel::ptToBeeline2(p1, p2, pt, nearpt);
if (minDist > d) {
minDist = d;
order = i;
}
else if (!PtInArea_Edge(odd, pt, p1, p2,
i > 0 ? pts[i-1] : pts[count-1])) {
continue;
}
}
if (order >= 0) {
return kPtOnEdge;
}
// 如果射线和多边形的交点数为偶数, 则 p==1, P在区外, 返回 kPtOutArea
// 为奇数则p==0, P在区内, 返回 kPtInArea
return 0 == odd ? kPtInArea : kPtOutArea;
}
bool mglnrel::isBetweenLine2(
const Point2d& a, const Point2d& b, const Point2d& pt, const Tol& tol)
{
if (!mglnrel::isColinear2(a, b, pt, tol))
return false;
// If ab not vertical, check betweenness on x; else on y.
if (a.x != b.x)
{
return ((a.x <= pt.x + tol.equalPoint())
&& (pt.x <= b.x + tol.equalPoint()))
|| ((a.x >= pt.x - tol.equalPoint())
&& (pt.x >= b.x - tol.equalPoint()));
}
else
{
return ((a.y <= pt.y + tol.equalPoint())
&& (pt.y <= b.y + tol.equalPoint()))
|| ((a.y >= pt.y - tol.equalPoint())
&& (pt.y >= b.y - tol.equalPoint()));
}
}
bool mglnrel::isLeftOn2(
const Point2d& a, const Point2d& b, const Point2d& pt, const Tol& tol)
{
float dist = (b-a).distanceToVector(pt-a);
return dist > -tol.equalPoint();
}
bool mglnrel::isColinear2(
const Point2d& a, const Point2d& b, const Point2d& pt, const Tol& tol)
{
float dist = (b-a).crossProduct(pt-a);
return fabsf(dist) < tol.equalPoint();
}
// 判断点pt是否在有向直线a->b的左边
GEOMAPI bool mgIsLeft2(
const Point2d& a, const Point2d& b, const Point2d& pt, const Tol& tol)
{
float dist = (b-a).distanceToVector(pt-a);
return dist > tol.equalPoint();
}