Question

在VC6.0中如何实现“判断一个点是否在一个不规则平面范围内（凹凸都可能）？？”

Answer 1

如果是凸多边形比较容易, 用射线和交点判断一下就可以了, 你的这个较为复杂,看看CGAL吧, 里面有算法
有个例子程序给你看看
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Polygon_2_algorithms.h>
#include <iostream>

typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef K::Point_2 Point;
using std::cout; using std::endl;

void check_inside(Point pt, Point *pgn_begin, Point *pgn_end, K traits)
{
cout << "The point " << pt;
switch(CGAL::bounded_side_2(pgn_begin, pgn_end,pt, traits)) {
case CGAL::ON_BOUNDED_SIDE :
cout << " is inside the polygon.\n";
break;
case CGAL::ON_BOUNDARY:
cout << " is on the polygon boundary.\n";
break;
case CGAL::ON_UNBOUNDED_SIDE:
cout << " is outside the polygon.\n";
break;
}
}

int main()
{
Point points[] = { Point(0,0), Point(5.1,0), Point(1,1), Point(0.5,6)};

// check if the polygon is simple.
cout << "The polygon is "
<< (CGAL::is_simple_2(points, points+4, K()) ? "" : "not ")
<< "simple." << endl;

check_inside(Point(0.5, 0.5), points, points+4, K());
check_inside(Point(1.5, 2.5), points, points+4, K());
check_inside(Point(2.5, 0), points, points+4, K());

return 0;
}