sutherland-hodgman算法vc++

Sutherland-Hodgman算法是一种计算多边形交集的算法，可以用于计算裁剪和填充等应用。下面是一个使用VC++实现Sutherland-Hodgman算法的示例代码：

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

struct Point {
    double x, y;
};

// 判断两个点是否在多边形的同一侧
bool SameSide(const Point& p1, const Point& p2, const Point& a, const Point& b) {
    double cp1 = (b.x - a.x) * (p1.y - a.y) - (b.y - a.y) * (p1.x - a.x);
    double cp2 = (b.x - a.x) * (p2.y - a.y) - (b.y - a.y) * (p2.x - a.x);
    return cp1 * cp2 >= 0;
}

// 计算两个点之间的交点
Point Intersect(const Point& p1, const Point& p2, const Point& a, const Point& b) {
    double u = ((a.y - b.y) * (p1.x - a.x) - (a.x - b.x) * (p1.y - a.y)) / ((b.x - a.x) * (p1.y - p2.y) - (b.y - a.y) * (p1.x - p2.x));
    return { p1.x + u * (p2.x - p1.x), p1.y + u * (p2.y - p1.y) };
}

// Sutherland-Hodgman算法
vector<Point> SutherlandHodgman(const vector<Point>& subjectPolygon, const vector<Point>& clipPolygon) {
    vector<Point> outputList = subjectPolygon;
    for (int i = 0; i < clipPolygon.size(); i++) {
        vector<Point> inputList = outputList;
        outputList.clear();
        Point S = clipPolygon[i];
        Point E = clipPolygon[(i + 1) % clipPolygon.size()];
        for (int j = 0; j < inputList.size(); j++) {
            Point P = inputList[j];
            Point Q = inputList[(j + 1) % inputList.size()];
            if (SameSide(P, S, E, Q)) {
                if (!SameSide(P, E, S, Q)) {
                    outputList.push_back(Intersect(P, Q, S, E));
                }
                outputList.push_back(Q);
            }
            else if (SameSide(P, E, S, Q)) {
                outputList.push_back(Intersect(P, Q, S, E));
            }
        }
    }
    return outputList;
}

int main() {
    vector<Point> subjectPolygon = { {0, 0}, {100, 0}, {100, 100}, {0, 100} };
    vector<Point> clipPolygon = { {50, 50}, {150, 50}, {150, 150}, {50, 150} };
    vector<Point> result = SutherlandHodgman(subjectPolygon, clipPolygon);
    for (int i = 0; i < result.size(); i++) {
        cout << "(" << result[i].x << ", " << result[i].y << ")" << endl;
    }
    return 0;
}

这个示例代码实现了一个计算矩形和正方形交集的例子。输入的两个多边形分别是`subjectPolygon`和`clipPolygon`，输出的多边形是`result`。程序的输出应该是一个四边形，表示矩形和正方形的交集。