一、简介

两点之间寻找最短路径，要考虑到存在障碍物遮挡和斜线移动的情况。

二、具体说明

说明可以参考下面的链接，对A*算法实现的描述。

三、具体实现

1、实现功能

2、寻路具体流程

3、关于F值

f = g + h

g表示当前移动到下一个点的消耗，平移为1，斜移动为 sqrt((x1-x2)**2 +(y1-y2)**2);

h表示当前移动到终点的消耗，不考虑斜移，不考虑障碍物

具体原理请查看下面的参考链接。

完整实现：

# -*- coding: utf-8 -*-

import os,sys,random,math

#地图设置

gameMapWidth = 10

gameMapHeight = 10

gameMap = []

#地图障碍物

obstacleCount = 5

#块状态

ITEM_STAT_NORMAL = 0 #空点

ITEM_STAT_OBSTACLE = 1 #障碍物

ITEM_STAT_START = 2 #起点

ITEM_STAT_END = 3 #终点

#起点和终点

spNum = -1

epNum = -1

#每块的属性

class Item:

def __init__(self,x,y,status):

self.x = x

self.y = y

self.status = status

self.mf = -1

self.mg = -1

self.mh = -1

self.mParent = None

self.isPath = 0

#初始化地图

def initMap():

for wc in xrange(gameMapWidth):

for hc in xrange(gameMapHeight):

gameMap.append(Item(wc,hc,ITEM_STAT_NORMAL))

#插入障碍物

for oc in xrange(obstacleCount):

choose = random.randint(gameMapWidth,gameMapWidth*gameMapHeight - 1)

gameMap[choose].status = ITEM_STAT_OBSTACLE

global spNum

global epNum

#选取起点和终点

while (spNum == -1):

choose = random.randint(0,gameMapWidth*gameMapHeight - 1)

if gameMap[choose].status == 0:

spNum = choose

gameMap[spNum].status = ITEM_STAT_START

while (epNum == -1):

choose = random.randint(0,gameMapWidth*gameMapHeight - 1)

if gameMap[choose].status == 0:

epNum = choose

gameMap[epNum].status = ITEM_STAT_END

#输出地图信息

def printMap():

for itemc in xrange(len(gameMap)):

if gameMap[itemc].status == ITEM_STAT_START:

print "START",

elif gameMap[itemc].status == ITEM_STAT_END:

print "END ",

elif gameMap[itemc].isPath == 1:

print "path ",

else:

print "%d " %(gameMap[itemc].status),

if (itemc + 1) % gameMapHeight == 0:

print "\n"

#寻路

def findPath():

global spNum

global epNum

#开启列表

openPointList = []

#关闭列表

closePointList = []

#开启列表插入起始点

openPointList.append(gameMap[spNum])

while (len(openPointList) > 0):

#寻找开启列表中最小预算值的点

minFPoint = findPointWithMinF(openPointList)

#从开启列表移除,添加到关闭列表

openPointList.remove(minFPoint)

closePointList.append(minFPoint)

#找到当前点周围点

surroundList = findSurroundPoint(minFPoint,closePointList)

#开始寻路

for sp in surroundList:

#存在在开启列表，说明上一块查找时并不是最优路径，考虑此次移动是否是最优路径

if sp in openPointList:

newPathG = CalcG(sp, minFPoint) #计算新路径下的G值

if newPathG < sp.mg:

sp.mg = newPathG

sp.mf = sp.mg + sp.mh

sp.mParent = minFPoint

else:

sp.mParent = minFPoint #当前查找到点指向上一个节点

CalcF(sp, gameMap[epNum])

openPointList.append(sp)

if gameMap[epNum] in openPointList:

gameMap[epNum].mParent = minFPoint

break

curp = gameMap[epNum]

while True:

curp.isPath = 1

curp = curp.mParent

if curp == None:

break

print "\n"

printMap()

def CalcG(point, minp):

return math.sqrt((point.x - point.mParent.x)**2 + (point.y - point.mParent.y)**2) + minp.mg

#计算每个点的F值

def CalcF(point,endp):

h = abs(endp.x - point.x) + abs(endp.y - point.y)

g = 0

if point.mParent == None:

g = 0

else:

g = point.mParent.mg + math.sqrt((point.x - point.mParent.x)**2 + (point.y - point.mParent.y)**2)

point.mg = g

point.mh = h

point.mf = g + h

return

#不能是障碍块，不包含在关闭列表中

def notObstacleAndClose(point,closePointList):

if point not in closePointList and point.status != ITEM_STAT_OBSTACLE:

return True

return False

#查找周围块

def findSurroundPoint(point,closePointList):

surroundList = []

up = None

down = None

left = None

right = None

leftUp = None

rightUp = None

leftDown = None

rightDown = None

#上面的点存在

if point.x > 0:

up = gameMap[gameMapHeight*(point.x - 1) + point.y]

if notObstacleAndClose(up,closePointList):

surroundList.append(up)

#下面的点存在

if point.x < gameMapWidth - 1:

down = gameMap[gameMapHeight*(point.x + 1)+ point.y]

if notObstacleAndClose(down,closePointList):

surroundList.append(down)

#左边的点存在

if point.y > 0:

left = gameMap[gameMapHeight*(point.x) + point.y - 1]

if notObstacleAndClose(left, closePointList):

surroundList.append(left)

#右边的点存在

if point.y < gameMapHeight - 1:

right = gameMap[gameMapHeight*(point.x) + point.y + 1]

if notObstacleAndClose(right,closePointList):

surroundList.append(right)

#斜方向的点还需考虑对应正方向不是障碍物

#左上角的点存在

if point.x > 0 and point.y > 0:

leftUp = gameMap[gameMapHeight*(point.x - 1) + point.y - 1]

if notObstacleAndClose(leftUp,closePointList) and left.status != ITEM_STAT_OBSTACLE and up.status != ITEM_STAT_OBSTACLE:

surroundList.append(leftUp)

#右上角的点存在

if point.x > 0 and point.y < gameMapHeight - 1:

rightUp = gameMap[gameMapHeight*(point.x-1) + point.y + 1]

if notObstacleAndClose(rightUp,closePointList) and right.status != ITEM_STAT_OBSTACLE and up.status != ITEM_STAT_OBSTACLE:

surroundList.append(rightUp)

#左下角的点存在

if point.x < gameMapWidth - 1 and point.y > 0:

leftDown = gameMap[gameMapHeight*(point.x+1) + point.y - 1]

if notObstacleAndClose(leftDown,closePointList) and left.status != ITEM_STAT_OBSTACLE and down.status != ITEM_STAT_OBSTACLE:

surroundList.append(leftDown)

#右下角的点存在

if point.x < gameMapWidth - 1 and point.y < gameMapHeight - 1:

rightDown = gameMap[gameMapHeight*(point.x+1) + point.y + 1]

if notObstacleAndClose(rightDown,closePointList) and right.status != ITEM_STAT_OBSTACLE and down.status != ITEM_STAT_OBSTACLE:

surroundList.append(rightDown)

return surroundList

#查找list中最小的f值

def findPointWithMinF(openPointList):

f = 0xffffff

temp = None

for pc in openPointList:

if pc.mf < f:

temp = pc

f = pc.mf

return temp

def main():

initMap() ##初始化地图

printMap() ##输出初始化地图信息

findPath() ##查找最优路径

#入口

main()

参考：

https://www.gamedev.net/articles/programming/artificial-intelligence/a-pathfinding-for-beginners-r2003/

https://blog.csdn.net/qq_33747722/article/details/78436919