Unity C#写的A*寻路

原地址：http://www.unity蛮牛.com/blog-13769-1078.html

首先看了这篇翻译外国人的文章http://www.raywenderlich.com/zh-hans/21503/a%E6%98%9F%E5%AF%BB%E8%B7%AF%E7%AE%97%E6%B3%95%E4%BB%8B%E7%BB%8D

 

 

1.定义地图节点，及初始化地图数据

[code]csharpcode：

using UnityEngine;
using System.Collections.Generic;

public class Map
{
    /// <summary>
    /// 初始化地图
    /// </summary>
    /// <returns></returns>
    public static Dictionary<string, MapInfo> GetMap()
    {
        Dictionary<string, MapInfo> temp = new Dictionary<string, MapInfo>();

        for (int i = 0; i < 10; i++)
        {
            string s = "";
            for (int j = 0; j < 10; j++)
            {
                int tt = 0;
                if (i > 1 && i < 8 && j == 5)
                {
                    tt = 1;
                }
                MapInfo mi = new MapInfo(i, j, tt);
                temp.Add(i + "-" + j, mi);
                s += mi.tag + " ";
            }
            Debug.Log(s);
        }
        return temp;
    }
}

/// <summary>
/// 地图节点
/// </summary>
public class MapInfo
{
    /// <summary>
    /// X
    /// </summary>
    public int x;
    /// <summary>
    /// Y
    /// </summary>
    public int y;
    /// <summary>
    /// 是否可行走
    /// </summary>
    public int tag;
    /// <summary>
    /// G
    /// </summary>
    public int gValue;
    /// <summary>
    /// H
    /// </summary>
    public int hValue;
    /// <summary>
    /// 父节点
    /// </summary>
    public MapInfo parent;

    public MapInfo()
    { }

    /// <summary>
    /// 构造
    /// </summary>
    /// <param name="x"></param>
    /// <param name="y"></param>
    /// <param name="tag"></param>
    public MapInfo(int x, int y,int tag)
    {
        this.x = x;
        this.y = y;
        this.tag = tag;
        this.gValue = 0;
        this.hValue = 0;
        this.parent = null;
    }
}

2.由起点终点寻路，有注释，知道原理的话，应该很容易懂

[code]csharpcode：

using UnityEngine;
using System.Collections.Generic;

public class AStar : MonoBehaviour
{
    /// <summary>
    /// 地图
    /// </summary>
    Dictionary<string, MapInfo> map;
    /// <summary>
    /// open列表
    /// </summary>
    Dictionary<string, MapInfo> openList = new Dictionary<string, MapInfo>();
    /// <summary>
    /// close列表
    /// </summary>
    Dictionary<string, MapInfo> closeList = new Dictionary<string, MapInfo>();

    /// <summary>
    /// 当前点
    /// </summary>
    MapInfo currentV;
    /// <summary>
    /// 当前点的相邻节点列表
    /// </summary>
    Dictionary<string, MapInfo> adjancentMap;


    // Use this for initialization
    void Start () 
    {
        map = Map.GetMap();
        MapInfo st = map["5-2"];//start
        MapInfo end = map["6-8"];//end

        FindPath(st, end);
    }
        
      
    /// <summary>
    /// 寻路
    /// </summary>
    /// <param name="start">起点</param>
    /// <param name="end">终点</param>
    public void FindPath(MapInfo start,MapInfo end)
    {
        openList.Add(start.x + "-" + start.y, start);

        do
        {
            currentV = GetTheLowestFrom(openList);

            closeList.Add(currentV.x + "-" + currentV.y, currentV);
            openList.Remove(currentV.x + "-" + currentV.y);

            if (closeList.ContainsKey(end.x + "-" + end.y))
            {
                Debug.Log("FindPath");

                PrintThePath(end);
                break;
            }

            adjancentMap = AdjacentList(currentV);

            foreach (string k in adjancentMap.Keys)
            {
                if (closeList.ContainsKey(k))
                {
                    continue;
                }

                if (!openList.ContainsKey(k))
                {
                    adjancentMap[k].parent = currentV;
                    adjancentMap[k].gValue = currentV.gValue + 1;
                    adjancentMap[k].hValue = GetManhattanDistance(adjancentMap[k], end);
                    openList.Add(k, adjancentMap[k]);
                }
                else
                {
                    int g = currentV.gValue + 1;
                    if (g < adjancentMap[k].gValue)
                    {
                        adjancentMap[k].gValue = g;
                        adjancentMap[k].parent = currentV;
                    }
                }
            }


        } while (openList.Count > 0);
    }

    /// <summary>
    /// 获取openlist中F最小的节点
    /// </summary>
    /// <param name="open"></param>
    /// <returns></returns>
    public MapInfo GetTheLowestFrom(Dictionary<string, MapInfo> open)
    {
        MapInfo result=null;
        int min = 10000;
        foreach (MapInfo m in open.Values)
        {
            if (m.gValue + m.hValue < min)
            {
                result = m;
                min = m.gValue + m.hValue;
            }
        }
        return result;
    }

    /// <summary>
    /// 获取当前节点的相邻节点
    /// </summary>
    /// <param name="m">当前节点</param>
    /// <returns></returns>
    public Dictionary<string, MapInfo> AdjacentList(MapInfo m)
    {
        Dictionary<string, MapInfo> resultDic=new Dictionary<string,MapInfo>();

        string left = (m.x - 1) + "-" + m.y;
        string right = (m.x + 1) + "-" + m.y;
        string top = m.x + "-" + (m.y - 1);
        string bot = m.x + "-" + (m.y + 1);

        if (map.ContainsKey(left))
        {
            if(map[left].tag==0)
                resultDic.Add(left, map[left]);
        }

        if (map.ContainsKey(right))
        {
            if (map[right].tag == 0)
                resultDic.Add(right, map[right]);
        }

        if (map.ContainsKey(top))
        {
            if (map[top].tag == 0)
                resultDic.Add(top, map[top]);
        }

        if (map.ContainsKey(bot))
        {
            if (map[bot].tag == 0)
                resultDic.Add(bot, map[bot]);
        }
        return resultDic;
    }

    /// <summary>
    /// 获得两个点的曼哈顿距离
    /// 作为估值函数
    /// </summary>
    /// <param name="st"></param>
    /// <param name="end"></param>
    /// <returns></returns>
    public int GetManhattanDistance(MapInfo st, MapInfo end)
    {
        int result = 0;
        result = Mathf.Abs(st.x - end.x) + Mathf.Abs(st.y - end.y);
        return result;
    }

    /// <summary>
    /// 输出路径
    /// </summary>
    /// <param name="end">终点</param>
    public void PrintThePath(MapInfo end)
    {
        string s = "";
        MapInfo m = end;
        while (m.parent != null)
        {
            s += "("+m.parent.x + "," + m.parent.y + ")->";            
            m = m.parent;
        }
        Debug.Log(s);
    }
}