将空间按照一定的方法进行分割，例如根据AOI范围的大小将整个游戏世界切分为固定大小的格子。当游戏物体位于场景的时候，根据坐标将它放入特定的格子中。
例如玩家1在位置7中，如果游戏内的AOI的范围为1个格子。当我们需要获取这个玩家周围的AOI对象时，只需要遍历7周围9个里面的对象即可。
实体的事件：
- 进入场景enter：进入一个格子，取出周围9格的对象，向它们发送
Enter(我)事件，同时向我发送Enter(对象)事件。 - 离开场景leave：取出周围9格的对象，向它们发送
Leave(我)事件。 - 移动move：
- 如果没跨格子，直接取9格的对象，向它们发送移动事件。
- 如果跨过格子，计算{OldGrid-NewGrid}，向它们发送
Leave(我)事件，向我发送Leave(对象)事件；计算{NewGrid-OldGrid}集合，向它们发送Enter(我)事件，向我发送Enter(对象事件；计算{NewGrid*OldGrid}集合，向他们发送Move(我)事件。
空间分割在计算AOI对象时，只需要遍历周围几个空间格子即可，大大提高了计算效率。
但是该方法也有缺点，格子数和空间大小成为正比，空间越大，所需要的内存空间也越大。
如果玩家数里远远小于空间的格子数，使用这种方法来计算AOI可能比全部遍历效率还差。
实现
实体Entity：有三个事件，enter.leave,move事件
class Entity(object):
# 场景实体
def __init__(self, eid, x, y):
self.id = eid # 角色ID
self.x = x
self.y = y
self.last_x = -1 # 是用来参与判断实体是否有进入或者离开 AOI
self.last_y = -1
def __str__(self):
return "<{0}, {1}-{2}>".format(self.id, self.x, self.y)
def enter(self, eobj):
print("{0} enter {1} view".format(eobj, self))
def leave(self, eobj):
print("{0} leave {1} view".format(eobj, self))
pass
def move(self, eobj):
print("{0} move in {1} view".format(eobj, self))
格子：场景根据大小分成若干格子，每个格子管理一个区域
角色所在的位置，由格子管理
class Grid(object):
# 格子
def __init__(self, gid, min_x, max_x, min_y, max_y):
self.gid = gid # 格子ID
self.min_x = min_x # 格子坐标x范围
self.max_x = max_x
self.min_y = min_y # 格子坐标y范围
self.max_y = max_y
self.players = set([]) # 角色ID
比如此图，分成36个格子
场景：控制生成格子数量，管理格子和实体对象
class Scene(object):
# 场景，由多个格子组成
def __init__(self, min_x, max_x, cnts_x, min_y, max_y, cnts_y):
self.min_x = min_x
self.max_x = max_x
self.cnts_x = cnts_x # X轴方向格子的数量
self.min_y = min_y
self.max_y = max_y
self.cnts_y = cnts_y # y轴方向格子的数量
self.grids = {} # 管理格子对象
self.map_entity = {} # 管理实体对象完整代码：
python版本：2.7
# -*- coding: utf-8 -*-
class Entity(object):
# 场景实体
def __init__(self, eid, x, y):
self.id = eid # 角色ID
self.x = x
self.y = y
self.last_x = -1 # 是用来参与判断实体是否有进入或者离开 AOI
self.last_y = -1
def __str__(self):
return "<{0}, {1}-{2}>".format(self.id, self.x, self.y)
def enter(self, eobj):
print("{0} enter {1} view".format(eobj, self))
def leave(self, eobj):
print("{0} leave {1} view".format(eobj, self))
pass
def move(self, eobj):
print("{0} move in {1} view".format(eobj, self))
class Grid(object):
# 格子
def __init__(self, gid, min_x, max_x, min_y, max_y):
self.gid = gid
self.min_x = min_x
self.max_x = max_x
self.min_y = min_y
self.max_y = max_y
self.players = set([]) # 角色ID
def __str__(self):
return "<{0}, {1}-{2}: {3}>,".format(self.gid, self.min_x, self.min_y, str(self.players))
def add(self, eid):
self.players.add(eid)
def remove(self, eid):
self.players.remove(eid)
def get_player_ids(self):
return list(self.players)
class Scene(object):
# 场景，由多个格子组成
def __init__(self, min_x, max_x, cnts_x, min_y, max_y, cnts_y):
self.min_x = min_x
self.max_x = max_x
self.cnts_x = cnts_x # X轴方向格子的数量
self.min_y = min_y
self.max_y = max_y
self.cnts_y = cnts_y # y轴方向格子的数量
self.grids = {}
self.map_entity = {} # 实体对象
self.init_grid()
def __str__(self):
res = ""
for y in xrange(self.cnts_y):
for x in xrange(self.cnts_x):
gid = y * self.cnts_x + x
res += str(self.grids[gid])
res += "\n"
return res
def init_grid(self):
# 生成格子
for y in xrange(self.cnts_y):
for x in xrange(self.cnts_x):
gid = y * self.cnts_x + x
min_x = self.min_x + x * self.grid_width()
max_x = self.min_x + (x + 1) * self.grid_width()
min_y = self.min_y + y * self.grid_height()
max_y = self.min_y + (y + 1) * self.grid_height()
self.grids[gid] = Grid(gid, min_x, max_x, min_y, max_y)
def grid_width(self):
# 每个格子在x轴方向的宽度
return (self.max_x - self.min_x) / self.cnts_x
def grid_height(self):
# 得到每个格子在Y轴方向高度
return (self.max_y - self.min_y) / self.cnts_y
def get_surround_grids_by_gid(self, gid, include_self=False):
# 周边的格子对象
surrounds = []
grid = self.grids[gid]
y, x = divmod(grid.gid, self.cnts_x)
for y_i, x_j in ((-1, 1), (-1, 0), (-1, -1), (0, -1), (0, 1), (1, 1), (1, 0), (1, -1)):
cal_y = y + y_i
cal_x = x + x_j
if cal_x < 0 or cal_x >= self.cnts_x:
continue
if cal_y < 0 or cal_y >= self.cnts_y:
continue
cal_gid = cal_y * self.cnts_x + cal_x
surrounds.append(self.grids[cal_gid])
return surrounds
def add_eid_grid(self, eid, gid):
self.grids[gid].add(eid)
def remove_eid_grid(self, eid, gid):
self.grids[gid].remove(eid)
def get_eids_by_gid(self, gid):
return self.grids[gid].get_player_ids()
def get_gid_by_pos(self, x, y):
# 通过，x, y得到对应格子ID
idx = (x - self.min_x) / self.grid_width()
idy = (y - self.min_y) / self.grid_height()
gid = idy * self.cnts_x + idx
return gid
def get_surround_eids_by_pos(self, x, y, include_self=False):
# 根据一个坐标 得到 周边九宫格之内的全部的 玩家ID集合
gid = self.get_gid_by_pos(x, y)
grids = self.get_surround_grids_by_gid(gid)
eids = []
for grid in grids:
eids.extend(grid.get_player_ids())
if include_self:
eids.extend(self.grids[gid].get_player_ids())
return eids
def add_to_grid_by_pos(self, eid, x, y):
# 通过坐标 将eid 加入到一个格子中
gid = self.get_gid_by_pos(x, y)
grid = self.grids[gid]
grid.add(eid)
return gid
def remove_to_grid_by_pos(self, eid, x, y):
# 通过坐标 将eid remove到一个格子中
gid = self.get_gid_by_pos(x, y)
grid = self.grids[gid]
grid.remove(eid)
def update_pos(self, update_eid, x, y):
if update_eid not in self.map_entity:
# 首次进入
eobj = Entity(update_eid, x, y)
self.map_entity[update_eid] = eobj
grip_id = self.add_to_grid_by_pos(update_eid, x, y)
eids = self.get_surround_eids_by_pos(x, y)
for eid in eids:
ob = self.map_entity[eid]
ob.enter(eobj)
else:
eobj = self.map_entity[update_eid]
eobj.last_x = eobj.x
eobj.last_y = eobj.y
eobj.x = x
eobj.y = y
# 格子内移动
old_gid = self.get_gid_by_pos(eobj.last_x, eobj.last_y)
new_gid = self.get_gid_by_pos(eobj.x, eobj.y)
if old_gid == new_gid:
eids = self.get_surround_eids_by_pos(x, y, True)
for eid in eids:
self.map_entity[eid].move(eobj)
else:
# 移动格子
self.remove_eid_grid(update_eid, old_gid)
self.add_eid_grid(update_eid, new_gid)
old_surround_gids = self.get_surround_grids_by_gid(old_gid)
new_surround_gids = self.get_surround_grids_by_gid(new_gid)
# 新格子事件处理
for grid in [grid for grid in new_surround_gids if grid not in old_surround_gids]:
for eid in grid.get_player_ids():
self.map_entity[eid].enter(eobj)
# 老格子事件处理
for grid in [grid for grid in old_surround_gids if grid not in new_surround_gids]:
for eid in grid.get_player_ids():
self.map_entity[eid].leave(eobj)
for grid in [grid for grid in old_surround_gids if grid in new_surround_gids]:
for eid in grid.get_player_ids():
self.map_entity[eid].move(eobj)
def test():
scene = Scene(0, 100, 4, 0, 100, 4)
scene.update_pos(1, 0, 0)
scene.update_pos(2, 50, 20)
scene.update_pos(3, 99, 99)
print(scene)
print("<25-1> sorround: {0}".format(scene.get_surround_eids_by_pos(25, 1, True)))
print("<50-50> sorround: {0}".format(scene.get_surround_eids_by_pos(50, 50, True)))
scene.update_pos(3, 25, 1)
scene.update_pos(3, 99, 99)
test()
运行结果：一个场景分成16个格子，大小为100 * 100
<0, 0-0: set([1])>,<1, 25-0: set([])>,<2, 50-0: set([2])>,<3, 75-0: set([])>,
<4, 0-25: set([])>,<5, 25-25: set([])>,<6, 50-25: set([])>,<7, 75-25: set([])>,
<8, 0-50: set([])>,<9, 25-50: set([])>,<10, 50-50: set([])>,<11, 75-50: set([])>,
<12, 0-75: set([])>,<13, 25-75: set([])>,<14, 50-75: set([])>,<15, 75-75: set([3])>,
<25-1> sorround: [1, 2]
<50-50> sorround: [3]
<3, 25-1> enter <1, 0-0> view
<3, 25-1> enter <2, 50-20> view
<3, 99-99> leave <1, 0-0> view
<3, 99-99> leave <2, 50-20> view深入探索AOI算法：深入探索AOI算法 - 知乎
