C++语言EasyX库VS2022边相关扫描算法代码

以下是使用EasyX库和VS2022编写的边相关扫描算法代码示例：

#include <graphics.h>
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

struct Edge
{
    int yMin;       // 边的下端点y坐标
    int yMax;       // 边的上端点y坐标
    float x;        // 边的当前扫描线x坐标
    float k;        // 边的斜率
};

bool cmp(const Edge& a, const Edge& b)
{
    return a.yMin < b.yMin;
}

void drawPolygon(vector<int>& x, vector<int>& y)
{
    setbkcolor(WHITE);
    cleardevice();
    setcolor(BLACK);
    fillpoly(x.size(), &x[0], &y[0]);
}

void scanLine(vector<int>& x, vector<int>& y)
{
    vector<Edge> edgeTable;
    int n = x.size();
    for (int i = 0; i < n; i++)
    {
        Edge e;
        if (y[i] < y[(i + 1) % n])
        {
            e.yMin = y[i];
            e.yMax = y[(i + 1) % n];
            e.x = x[i];
            e.k = (float)(x[(i + 1) % n] - x[i]) / (float)(y[(i + 1) % n] - y[i]);
        }
        else
        {
            e.yMin = y[(i + 1) % n];
            e.yMax = y[i];
            e.x = x[(i + 1) % n];
            e.k = (float)(x[i] - x[(i + 1) % n]) / (float)(y[i] - y[(i + 1) % n]);
        }
        edgeTable.push_back(e);
    }

    sort(edgeTable.begin(), edgeTable.end(), cmp);

    vector<int> activeList;
    int y = edgeTable[0].yMin;
    while (y <= edgeTable[edgeTable.size() - 1].yMax)
    {
        for (int i = 0; i < edgeTable.size(); i++)
        {
            if (edgeTable[i].yMin == y)
            {
                activeList.push_back(i);
            }
            else if (edgeTable[i].yMax == y)
            {
                for (int j = 0; j < activeList.size(); j++)
                {
                    if (activeList[j] == i)
                    {
                        activeList.erase(activeList.begin() + j);
                        break;
                    }
                }
            }
        }

        sort(activeList.begin(), activeList.end(), [&](int a, int b) {return edgeTable[a].x < edgeTable[b].x; });

        for (int i = 0; i < activeList.size(); i += 2)
        {
            int x1 = (int)(edgeTable[activeList[i]].x + 0.5);
            int x2 = (int)(edgeTable[activeList[i + 1]].x + 0.5);
            line(x1, y, x2, y);
        }

        for (int i = 0; i < activeList.size(); i++)
        {
            edgeTable[activeList[i]].x += edgeTable[activeList[i]].k;
        }

        y++;
        Sleep(20);
    }
}

int main()
{
    initgraph(640, 480);

    vector<int> x = { 150, 300, 250, 100 };
    vector<int> y = { 150, 150, 300, 300 };

    drawPolygon(x, y);
    scanLine(x, y);

    _getch();
    closegraph();
    return 0;
}

该代码实现了对多边形进行边相关扫描算法，并使用EasyX库在窗口中显示出扫描结果。其中，`drawPolygon`函数用于绘制多边形，`scanLine`函数用于对多边形进行扫描，并在窗口中显示扫描结果。具体实现细节可以查看代码注释。