Unity之A*算法
Astar.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Astar : MonoBehaviour {
private const int mapWidth = 8;
private const int mapHeight = 6;
private Point[,] map = new Point[mapWidth, mapHeight];
void Start () {
InitMap();
Point start = map[2, 3];
Point end = map[6, 3];
//测试
//List list = GetSurroundPoints(map[3, 3]);
//foreach(Point p in list)
//{
// Debug.Log(p.X + "- "+ p.Y);
//}
FindPath(start, end);
ShowPath(start, end);
}
private void InitMap(){
for(int x = 0; x < mapWidth; x++)
{
for(int y = 0; y <mapHeight; y++)
{
map[x, y] = new Point(x, y);
}
}
map[4, 2].IsWall = true;
map[4, 3].IsWall = true;
map[4, 4].IsWall = true;
}
private void FindPath(Point start, Point end)
{
List<Point> openList = new List<Point>();
List<Point> closeList = new List<Point>();
openList.Add(start);
while (openList.Count > 0)
{
Point point = FindMinOfPoint(openList);
openList.Remove(point);
closeList.Add(point);
List<Point> surroundPoints = GetSurroundPoints(point);
PointFilter(surroundPoints, closeList);
foreach(Point surroundPoint in surroundPoints)
{
if(openList.IndexOf(surroundPoint) > -1)
{
float nowG = CalcG(surroundPoint, point);
if(nowG < surroundPoint.G)
{
surroundPoint.UpdateParent(surroundPoint, nowG);
}
}
else
{
surroundPoint.Parent = point;
CalcF(surroundPoint, end);
openList.Add(surroundPoint);
}
}
//判断end是否在列表中
if(openList.IndexOf(end) != -1)
{
break;
}
}
}
private void ShowPath(Point start, Point end)
{
Point temp = end;
Color c;
Debug.Log(temp.Parent.X + "," + temp.Parent.Y);
//while (true)
//{
// //Debug.Log(temp.X + "," + temp.Y);
// if(temp == start)
// {
// c = Color.green;
// }else if(temp == end)
// {
// c = Color.red;
// }
// else
// {
// c = Color.gray;
// }
// CreateCube(temp.X, temp.Y, c);
// if (temp.Parent == null)
// break;
// temp = temp.Parent;
//}
for (int x = 0; x < mapWidth; x++)
{
for (int y = 0; y < mapHeight; y++)
{
if(map[x, y].IsWall)
{
CreateCube(x, y, Color.blue);
}
}
}
}
private void CreateCube(int x, int y, Color color)
{
GameObject go = GameObject.CreatePrimitive(PrimitiveType.Cube);
go.transform.position = new Vector3(x, y, 0);
go.GetComponent<Renderer>().material.color = color;
}
//过滤
private void PointFilter(List<Point> src, List<Point> closeList)
{
foreach(Point p in closeList)
{
if(src.IndexOf(p) != -1)
{
src.Remove(p);
}
}
}
private List<Point> GetSurroundPoints(Point point)
{
Point up = null, down = null, left = null, right = null, lu = null, ru = null, ld = null, rd = null;
//是否是最上面
if(point.Y < mapHeight - 1)
{
up = map[point.X, point.Y + 1];
}
//最下面
if(point.Y > 0)
{
down = map[point.X, point.Y - 1];
}
if(point.X > 0)
{
left = map[point.X - 1, point.Y];
}
if(point.X < mapWidth - 1)
{
right = map[point.X + 1, point.Y];
}
if (up != null && left != null)
{
lu = map[point.X - 1, point.Y + 1];
}
if (up != null && right != null)
{
ru = map[point.X + 1, point.Y + 1];
}
if (down != null && left != null)
{
ld = map[point.X -1, point.Y -1];
}
if (down != null && right != null)
{
rd = map[point.X + 1, point.Y - 1];
}
List<Point> list = new List<Point>();
if(down != null && down.IsWall == false)
{
list.Add(down);
}
if (up != null && up.IsWall == false)
{
list.Add(up);
}
if (left != null && left.IsWall == false)
{
list.Add(left);
}
if (right != null && right.IsWall == false)
{
list.Add(right);
}
if(lu != null && lu.IsWall == false && left != null && left.IsWall == false && up != null && up.IsWall == false)
{
list.Add(lu);
}
if (ru != null && ru.IsWall == false && right != null && right.IsWall == false && up != null && up.IsWall == false)
{
list.Add(ru);
}
if (ld != null && ld.IsWall == false && left != null && left.IsWall == false && down != null && down.IsWall == false)
{
list.Add(ld);
}
if (rd != null && rd.IsWall == false && right != null && right.IsWall == false && down != null && down.IsWall == false)
{
list.Add(rd);
}
return list;
}
private Point FindMinOfPoint(List<Point> openList)
{
float f = float.MaxValue;
Point temp = null;
foreach(Point p in openList)
{
if(p.F < f)
{
temp = p;
f = p.F;
}
}
return temp;
}
private float CalcG(Point now, Point parent)
{
return Vector2.Distance(new Vector2(now.X, now.Y), new Vector2(parent.X, parent.Y)) + now.Parent.G;
}
private void CalcF(Point now, Point end)
{
//F = G + H
float h = Mathf.Abs(end.X - now.X) + Mathf.Abs(end.Y - now.Y);
float g = 0;
if(now.Parent == null)
{
g = 0;
}
else
{
g = Vector2.Distance(new Vector2(now.X, now.Y), new Vector2(now.Parent.X, now.Parent.Y)) + now.Parent.G;
}
float f = g + h;
now.F = f;
now.G = g;
now.H = h;
}
}
Point.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Point{
public Point Parent { get; set; }
public float F { get; set; }
public float G { get; set; }
public float H { get; set; }
public int X { get; set; }
public int Y { get; set; }
public bool IsWall { get; set; }
public Point(int x, int y, Point parent = null)
{
this.X = x;
this.Y = y;
this.Parent = parent;
}
public void UpdateParent(Point parent, float g)
{
this.Parent = parent;
this.G = g;
this.F = G + H;
}
}