【Unity3D】A*寻路（2D究极简单版）

运行后点击透明格子empty即执行从(0,0)起点到点击为止终点（测试是(5,5)）如下图

UICamera深度要比MainCamera大，Clear Flags:Depth only，正交视野
MainCamera保持原样；注意Line绘线物体的位置大小旋转信息，不然无法看到线条。

empty是透明图片格子，代表可通过路径节点；wall是白色图片格子，代表墙体。

using UnityEngine;
public class Empty : MonoBehaviour
{
    [HideInInspector]
    public Vector2Int pos;
    public void OnButtonClick()
    {
        AStarTest.Instance.PlayAstar(pos);
    }
}

A*寻路原理：Unity人工智能AI编程知识_实验2-2 群组行为-CSDN博客  

using System;
using System.Collections.Generic;
using UnityEngine;
using System.Linq;

public class AStarTest : MonoBehaviour
{
    private static AStarTest _instance;
    public static AStarTest Instance
    {
        get
        {
            return _instance;
        }
    }
    private int[,] map = {
        {0,0,0,1,0,0 },
        {0,1,1,1,0,1 },
        {0,0,1,0,1,0 },
        {0,0,0,0,1,0 },
        {1,1,1,0,0,0 },
        {0,0,1,1,0,0 },
    };

    private Vector2 wallSize;

    public Transform wallParent;
    public GameObject wallPrefab;
    public GameObject emptyPrefab;

    public class Point
    {
        public Vector2Int pos;
        public Point parent;
        public float F { get { return G + H; } } //F = G + H
        public float G; //G = parent.G + Distance(parent,self)
        public float H; //H = Distance(self, end)

        public string GetString()
        {
            return "pos:" + pos + ",F:" + F + ",G:" + G + ",H:" + H + "\n";
        }
    }

    private List<Point> openList = new List<Point>();
    private List<Point> closeList = new List<Point>();

    public LineRenderer lineRenderer;
    public RectTransform[,] rectTransformMap;

    private void Awake()
    {
        _instance = this;
    }

    void Start()
    {
        wallSize = wallPrefab.GetComponent<RectTransform>().rect.size;
        int mapWidth = map.GetLength(0);
        int mapHeight = map.GetLength(1);
        Vector2 offsetPos = new Vector2(mapWidth / 2.0f * wallSize.x, -mapHeight / 2.0f * wallSize.y);

        rectTransformMap = new RectTransform[mapWidth, mapHeight];
        for (int i = 0; i < mapWidth; i++)
        {
            for (int j = 0; j < mapHeight; j++)
            {
                GameObject go;
                int num = map[i, j];
                if (num == 1)
                {
                    //墙
                    go = GameObject.Instantiate(wallPrefab, wallParent);
                    go.name = $"wall {i}_{j}";
                }
                else
                {
                    //空
                    go = GameObject.Instantiate(emptyPrefab, wallParent);
                    go.name = $"empty {i}_{j}";
                    go.GetComponent<Empty>().pos = new Vector2Int(i, j);
                }
                rectTransformMap[i, j] = go.GetComponent<RectTransform>();
                rectTransformMap[i, j].anchoredPosition = new Vector2(i * wallSize.x, -j * wallSize.y) - offsetPos;
            }
        }
    }

    public void PlayAstar(Vector2Int endPos)
    {

        Debug.Log(endPos);
        openList.Clear();
        closeList.Clear();

        openList.Add(new Point()
        {
            G = 0f,
            H = GetC(new Vector2Int(0, 0), endPos),
            parent = null,
            pos = new Vector2Int(0, 0),
        });
        List<Vector2Int> resultList = CalculateAstar(endPos);
        if (resultList != null)
        {
            lineRenderer.positionCount = resultList.Count;
            for (int i = 0; i < resultList.Count; i++)
            {
                Vector2Int pos = resultList[i];
                lineRenderer.SetPosition(i, rectTransformMap[pos.x, pos.y].anchoredPosition);
            }
        }
        else
        {
            Debug.LogError("寻路失败;");
        }
    }

    private List<Vector2Int> CalculateAstar(Vector2Int endPos)
    {
        int cnt = 0;
        while (true)
        {
            //存在父节点说明已经结束            
            if (openList.Exists(x => x.pos.Equals(endPos)))
            {
                Debug.Log("找到父节点~" + endPos + ",迭代次数:"  + cnt);
                List<Vector2Int> resultList = new List<Vector2Int>();
                Point endPoint = openList.Find(x => x.pos.Equals(endPos));
                resultList.Add(endPoint.pos);
                Point parent = endPoint.parent;
                while (parent != null)
                {
                    resultList.Add(parent.pos);
                    parent = parent.parent;
                }
                return resultList;
            }

            cnt++;
            if (cnt > 100 * map.GetLength(0) * map.GetLength(1))
            {
                Debug.LogError(cnt);
                return null;
            }

            //从列表取最小F值的Point开始遍历
            Point currentPoint = openList.OrderBy(x => x.F).FirstOrDefault();
            string str = "";
            foreach(var v in openList)
            {
                str += v.GetString();
            }
            Debug.Log("最小F：" + currentPoint.GetString() + "\n" + str);
            Vector2Int pos = currentPoint.pos;
            for (int i = -1; i <= 1; i++)
            {
                for (int j = -1; j <= 1; j++)
                {
                    if (i == 0 && j == 0)
                    {
                        continue;
                    }
                    //过滤越界、墙体、已处理节点（存在闭合列表的节点）
                    Vector2Int tempPos = new Vector2Int(i + pos.x, j + pos.y);
                    if (tempPos.x < 0 || tempPos.x >= map.GetLength(0) || tempPos.y < 0 || tempPos.y >= map.GetLength(1)
                        || map[tempPos.x, tempPos.y] == 1
                        || closeList.Exists(x => x.pos.Equals(tempPos)))
                    {
                        continue;
                    }
                    //判断tempPos该节点是否已经计算,  在openList的就是已经计算的
                    Point tempPoint = openList.Find(x => x.pos.Equals(tempPos));
                    float newG = currentPoint.G + Vector2.Distance(currentPoint.pos, tempPos);
                    if (tempPoint != null)
                    {
                        //H固定不变,因此判断旧的G值和当前计算出的G值，如果当前G值更小，需要改变节点数据的父节点和G值为当前的，否则保持原样
                        float oldG = tempPoint.G;
                        if (newG < oldG)
                        {
                            tempPoint.G = newG;
                            tempPoint.parent = currentPoint;
                            Debug.Log("更新节点:" + tempPoint.pos + ", newG:" + newG + ", oldG:" + oldG + ",parent:" + tempPoint.parent.pos);
                        }
                    }
                    else
                    {
                        tempPoint = new Point()
                        {
                            G = newG,
                            H = GetC(tempPos, endPos),
                            pos = tempPos,
                            parent = currentPoint
                        };
                        Debug.Log("新加入节点:" + tempPoint.pos + ", newG:" + newG + ", parent:" + currentPoint.pos);
                        openList.Add(tempPoint);
                    }
                }
            }

            //已处理过的当前节点从开启列表移除,并放入关闭列表
            openList.Remove(currentPoint);
            closeList.Add(currentPoint);
        }
    }

    private float GetC(Vector2Int a, Vector2Int b)
    {
        return Math.Abs(a.x - b.x) + Math.Abs(a.y - b.y);
    }
}