#include <iostream>
#include <stack>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

void main()
{
	Mat input_img = imread("1.jpg");//输入图片路径
	cvtColor(input_img, input_img, CV_BGR2GRAY);

	//八邻域
	Point2d point_array[8] = {
		Point2d(-1,-1),
		Point2d(-1,0),
		Point2d(-1,1),
		Point2d(0,-1),
		Point2d(0,1),
		Point2d(1,-1),
		Point2d(1,0),
		Point2d(1,1)
	};

	stack<Point2d> point_stack;
	Point2d start_point(0, 0);//初始点
	point_stack.push(start_point);

	Mat output_img = Mat::zeros(input_img.size(), CV_8UC1);
	output_img.at<uchar>(start_point.x, start_point.y) = 255;
	int init_value = input_img.at<uchar>(start_point.x, start_point.y);

	Point2d p;

	while (!point_stack.empty())
	{
		p = point_stack.top();
		point_stack.pop();

		for (int i = 0; i < 8; i++)
		{
			Point2d temp_p = p + point_array[i];
			if (temp_p.x<0 || temp_p.y<0 || temp_p.x>input_img.cols - 1 || temp_p.y>input_img.rows)
			{
				continue;
			}

			int flag = output_img.at<uchar>(temp_p.y, temp_p.x);
			int value = input_img.at<uchar>(temp_p.y, temp_p.x);
			if (!flag && abs(value - init_value) < 30)
			{
				output_img.at<uchar>(temp_p.y, temp_p.x) = 165;
				point_stack.push(temp_p);
			}
		}
	}
	imshow("result", output_img);
	waitKey(0);
	return;
}