功能：有效边表转换算法 参数说明： vertices2---顶点列表 VertexNum ---顶点数目备注： DrawPixelint x int y --绘制像素点x yvoid CPolygon_ConversionViewActive_Edge_Table_Conersionint Vertices2 int VertexNum return;完成有效边表转换算法并

void CPolygon_ConversionView::Active_Edge_Table_Conersion(int Vertices[][2], int VertexNum) { // 定义活化边表和扫描线 vector<Edge*> AET; int scanLine = Vertices[0][1];

// 初始化活化边表
for (int i = 0; i < VertexNum; i++) {
    Edge* e = new Edge();
    int x1 = Vertices[i][0];
    int y1 = Vertices[i][1];
    int x2 = Vertices[(i + 1) % VertexNum][0];
    int y2 = Vertices[(i + 1) % VertexNum][1];
    if (y1 != y2) { // 排除水平边
        if (y1 > y2) { // 保证 e->y1 < e->y2
            swap(x1, x2);
            swap(y1, y2);
        }
        // 计算斜率和截距
        e->k = float(x2 - x1) / float(y2 - y1);
        e->b = x1 - e->k * y1;
        e->y1 = y1;
        e->y2 = y2;
        AET.push_back(e);
    }
}

// 按 y 坐标排序
sort(AET.begin(), AET.end(), EdgeSort);

// 循环处理每一行扫描线
while (!AET.empty()) {
    // 从活化边表中删除 y2 <= scanLine 的边
    for (auto iter = AET.begin(); iter != AET.end();) {
        if ((*iter)->y2 <= scanLine) {
            delete (*iter);
            iter = AET.erase(iter);
        } else {
            iter++;
        }
    }
    
    // 将 AET 中的边按 x 坐标排序
    sort(AET.begin(), AET.end(), EdgeXSort);
    
    // 绘制每一对相邻交点之间的像素
    for (int i = 0; i < AET.size(); i += 2) {
        int x1 = ceil(AET[i]->x);
        int x2 = floor(AET[i + 1]->x);
        for (int x = x1; x <= x2; x++) {
            DrawPixel(x, scanLine);
        }
        // 更新每条边的 x 坐标
        AET[i]->x += AET[i]->k;
        AET[i + 1]->x += AET[i + 1]->k;
    }
    
    // 更新扫描线的 y 坐标
    scanLine++;
    
    // 将新边插入 AET
    for (auto iter = AET.begin(); iter != AET.end();) {
        Edge* e = (*iter);
        if (e->y1 == scanLine) {
            iter = AET.erase(iter);
            continue;
        }
        e->x = e->k * scanLine + e->b;
        iter++;
    }
    for (int i = 0; i < VertexNum; i++) {
        int y1 = Vertices[i][1];
        int y2 = Vertices[(i + 1) % VertexNum][1];
        if (y1 != y2 && y1 == scanLine) {
            Edge* e = new Edge();
            int x1 = Vertices[i][0];
            int x2 = Vertices[(i + 1) % VertexNum][0];
            if (y1 > y2) {
                swap(x1, x2);
                swap(y1, y2);
            }
            e->k = float(x2 - x1) / float(y2 - y1);
            e->b = x1 - e->k * y1;
            e->y1 = y1;
            e->y2 = y2;
            e->x = e->k * scanLine + e->b;
            AET.push_back(e);
        }
    }
    sort(AET.begin(), AET.end(), EdgeSort);
}

}

// 活化边表排序函数，按 y1 坐标升序排序 bool EdgeSort(Edge* e1, Edge* e2) { return e1->y1 < e2->y1; }

// 活化边表排序函数，按 x 坐标升序排序 bool EdgeXSort(Edge* e1, Edge* e2) { return e1->x < e2->x; }

// 绘制像素点函数，略