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;补全并添加必要代码

void CPolygon_ConversionView::Active_Edge_Table_Conersion(int Vertices[][2], int VertexNum) { //1.构造活性边表 vector<vector> AET; //活性边表 AET.resize(VertexNum); for (int i = 0; i < VertexNum; i++) { 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) continue; //忽略水平边

	ActiveEdge edge;
	if (y1 > y2) //下端点在后面
	{
		edge.X = x2;
		edge.Dx = (float)(x1 - x2) / (float)(y1 - y2);
		edge.Ymax = y1;
	}
	else //下端点在前面
	{
		edge.X = x1;
		edge.Dx = (float)(x2 - x1) / (float)(y2 - y1);
		edge.Ymax = y2;
	}

	AET[min(y1, y2)].push_back(edge);
}

//2.填充像素
vector<ActiveEdge> NET; //新边表
int scanLine = Vertices[0][1]; //扫描线
while (!AET.empty() || !NET.empty())
{
	//2.1 将新边表中的边插入到活性边表中
	for (auto it = NET.begin(); it != NET.end();)
	{
		AET[it->Ymax - scanLine].push_back(*it);
		it = NET.erase(it);
	}

	//2.2 按照X值排序
	for (auto& edges : AET)
	{
		sort(edges.begin(), edges.end(), [](const ActiveEdge& a, const ActiveEdge& b) {
			return a.X < b.X;
			});
	}

	//2.3 填充扫描线上的像素
	for (auto& edges : AET)
	{
		for (int i = 0; i < (int)edges.size(); i += 2)
		{
			int x1 = ceil(edges[i].X);
			int x2 = floor(edges[i + 1].X);
			if (x1 <= x2)
			{
				for (int x = x1; x <= x2; x++)
				{
					DrawPixel(x, scanLine);
				}
			}
		}

		//2.4 更新X值
		for (auto& edge : edges)
		{
			edge.X += edge.Dx;
		}

		//2.5 删除Ymax <= scanLine的边
		edges.erase(remove_if(edges.begin(), edges.end(), [scanLine](const ActiveEdge& edge) {
			return edge.Ymax <= scanLine;
			}), edges.end());
	}

	//2.6 扫描线+1
	scanLine++;

	//2.7 更新新边表
	for (auto& edges : AET)
	{
		for (auto& edge : edges)
		{
			if (edge.Ymax == scanLine)
			{
				NET.push_back(edge);
			}
		}
	}

	//2.8 删除活性边表中所有的空链表
	AET.erase(remove_if(AET.begin(), AET.end(), [](const vector<ActiveEdge>& edges) {
		return edges.empty();
		}), AET.end());
}

}