有效的敌人回避,以更少的敌人进行寻路
Efficient enemy avoidance for pathfinding with fewer enemies
我目前正在使用 Python 开发一款 2D 自上而下的 rogue-like 游戏。该地图是一个地牢,包含许多开放的矩形房间 (image),每个房间内大约有 2-4 个敌人。我目前正在寻求实现一个寻路系统,敌人将在其中相互移动并试图蜂拥而至玩家。
到目前为止,我已经实现了一个 A* 算法,它确实允许敌人以这种方式导航和蜂拥而至玩家。然而,我的方法导致帧率非常低:通常在 15 FPS 左右,但当敌人无法到达玩家时,它会低至 1 FPS 以下。我觉得这是非常低效的,因为正在为每一帧的每个敌人进行寻路。目前,其他敌人被视为 A* 算法的障碍物,唯一的优化是如果没有障碍物,敌人将直接向玩家移动。这是代码:
import heapq
#...
FLOOR = 1
#...
class Game:
def __init__(self):
#...
self.pathfindingGranularity = 5
# Slope and line intersection functions are based on: https://www.codeproject.com/Tips/864704/Python-Line-Intersection-for-Pygame
def lineInRect(self, start, end, r):
if start in r and end in r: return True
if self.segmentIntersect(start, end, r.origin, Point(r.x + r.width, r.y)) is not None: return True
if self.segmentIntersect(start, end, Point(r.x, r.y + r.height), Point(r.x + r.width, r.y + r.height)) is not None: return True
if self.segmentIntersect(start, end, r.origin, Point(r.x, r.y + r.height)) is not None: return True
if self.segmentIntersect(start, end, Point(r.x + r.width, r.y), Point(r.x + r.width, r.y + r.height)) is not None: return True
return False
def slope(self, p1, p2):
if p2.x - p1.x == 0: return 1e10
return (p2.y - p1.y) / (p2.x - p1.x)
def yIntercept(self, slope, p1):
return p1.y - slope * p1.x
def lineIntersect(self, start1, end1, start2, end2):
min_allowed = 1e-5
big_value = 1e10
m1 = self.slope(start1, end1)
b1 = self.yIntercept(m1, start1)
m2 = self.slope(start2, end2)
b2 = self.yIntercept(m2, start2)
if abs(m1 - m2) < min_allowed: x = big_value if (b2 - b1 >= 0) else -big_value
else: x = (b2 - b1) / (m1 - m2)
y = m1 * x + b1
return Point(x, y)
def segmentIntersect(self, start1, end1, start2, end2):
intersection = self.lineIntersect(start1, end1, start2, end2)
def approx(f):
return round(f * 10000) / 10000
if not approx(start1.x) <= approx(intersection.x) <= approx(end1.x):
if not approx(end1.x) <= approx(intersection.x) <= approx(start1.x):
return None
if not approx(start2.x) <= approx(intersection.x) <= approx(end2.x):
if not approx(end2.x) <= approx(intersection.x) <= approx(start2.x):
return None
if not approx(start1.y) <= approx(intersection.y) <= approx(end1.y):
if not approx(end1.y) <= approx(intersection.y) <= approx(start1.y):
return None
if not approx(start2.y) <= approx(intersection.y) <= approx(end2.y):
if not approx(end2.y) <= approx(intersection.y) <= approx(start2.y):
return None
return intersection
class Enemy (Entity):
def update(self, game):
#...
if not self.getRect().intersects(game.player.getRect()) and self.canMove():
self.generatePath(game)
if self.path:
# Move towards player
elif self.canMove():
# Hurt the player
#...
def generatePath(self, game):
if not self.lineOccupied(Point(self.x, self.y), game.player.getCenterpoint(), game):
self.path = [game.player.getCenterpoint()]
return
frontier = PriorityQueue()
start = Point(self.x, self.y)
frontier.put(start, 0)
came_from = {}
came_from[start] = None
done = False
while not frontier.empty():
current = frontier.get()
if Rect(current.x + self.hitbox.x, current.y + self.hitbox.y, self.hitbox.w, self.hitbox.h).intersects(game.player.getRect()):
done = True
break
for next in self.findAdjacents(current, game):
if self.lineOccupied(current, next, game): continue
if next not in came_from:
priority = self.heuristic(next, game)
frontier.put(next, priority)
came_from[next] = current
if not done:
self.path.clear()
else:
p = [current]
while came_from[p[-1]] is not None:
p.append(came_from[p[-1]])
self.path = p[::-1][1:]
i = 0
def findAdjacents(self, currentPoint, game):
d = 1 / game.pathfindingGranularity
for x in (currentPoint.x - d, currentPoint.x, currentPoint.x + d):
for y in (currentPoint.y - d, currentPoint.y, currentPoint.y + d):
if x == currentPoint.x and y == currentPoint.y: continue
elif self.canWalkAtCoords(x, y, game):
yield Point(x, y)
def canWalkAtCoords(self, x, y, game):
for nx in (x, x + self.hitbox.w):
for ny in (y, y + self.hitbox.h):
if game.blockAt(nx, ny) != FLOOR:
return False
return True
def lineOccupied(self, start, end, game):
for e in self.room.enemies:
if e is self:
continue
for xo in (self.hitbox.x, self.hitbox.x + self.hitbox.w):
for yo in (self.hitbox.y, self.hitbox.y + self.hitbox.h):
if game.lineInRect(start + Point(xo, yo), end + Point(xo, yo), e.getRect()):
return True
return False
我觉得应该有一个更有效的解决方案,尤其是考虑到房间是矩形的,没有敌人需要四处移动的额外墙壁或障碍物,但到目前为止我正在寻找解决方案空手而归。我可以做一些优化来提高程序的性能吗?或者,如果没有,我应该研究更好的寻路方法吗?任何帮助将不胜感激!
你应该尝试让你的寻路从你的角色开始,然后使用广度优先搜索(对斜率进行一些调整)展开。每次遇到敌人,你都可以计算出它走向玩家的最佳路径。
这样一来,您只需要在整个棋盘上传球一次,而不是针对每个敌人传球一次。
如果您需要更多详细信息,请告诉我。
我目前正在使用 Python 开发一款 2D 自上而下的 rogue-like 游戏。该地图是一个地牢,包含许多开放的矩形房间 (image),每个房间内大约有 2-4 个敌人。我目前正在寻求实现一个寻路系统,敌人将在其中相互移动并试图蜂拥而至玩家。
到目前为止,我已经实现了一个 A* 算法,它确实允许敌人以这种方式导航和蜂拥而至玩家。然而,我的方法导致帧率非常低:通常在 15 FPS 左右,但当敌人无法到达玩家时,它会低至 1 FPS 以下。我觉得这是非常低效的,因为正在为每一帧的每个敌人进行寻路。目前,其他敌人被视为 A* 算法的障碍物,唯一的优化是如果没有障碍物,敌人将直接向玩家移动。这是代码:
import heapq
#...
FLOOR = 1
#...
class Game:
def __init__(self):
#...
self.pathfindingGranularity = 5
# Slope and line intersection functions are based on: https://www.codeproject.com/Tips/864704/Python-Line-Intersection-for-Pygame
def lineInRect(self, start, end, r):
if start in r and end in r: return True
if self.segmentIntersect(start, end, r.origin, Point(r.x + r.width, r.y)) is not None: return True
if self.segmentIntersect(start, end, Point(r.x, r.y + r.height), Point(r.x + r.width, r.y + r.height)) is not None: return True
if self.segmentIntersect(start, end, r.origin, Point(r.x, r.y + r.height)) is not None: return True
if self.segmentIntersect(start, end, Point(r.x + r.width, r.y), Point(r.x + r.width, r.y + r.height)) is not None: return True
return False
def slope(self, p1, p2):
if p2.x - p1.x == 0: return 1e10
return (p2.y - p1.y) / (p2.x - p1.x)
def yIntercept(self, slope, p1):
return p1.y - slope * p1.x
def lineIntersect(self, start1, end1, start2, end2):
min_allowed = 1e-5
big_value = 1e10
m1 = self.slope(start1, end1)
b1 = self.yIntercept(m1, start1)
m2 = self.slope(start2, end2)
b2 = self.yIntercept(m2, start2)
if abs(m1 - m2) < min_allowed: x = big_value if (b2 - b1 >= 0) else -big_value
else: x = (b2 - b1) / (m1 - m2)
y = m1 * x + b1
return Point(x, y)
def segmentIntersect(self, start1, end1, start2, end2):
intersection = self.lineIntersect(start1, end1, start2, end2)
def approx(f):
return round(f * 10000) / 10000
if not approx(start1.x) <= approx(intersection.x) <= approx(end1.x):
if not approx(end1.x) <= approx(intersection.x) <= approx(start1.x):
return None
if not approx(start2.x) <= approx(intersection.x) <= approx(end2.x):
if not approx(end2.x) <= approx(intersection.x) <= approx(start2.x):
return None
if not approx(start1.y) <= approx(intersection.y) <= approx(end1.y):
if not approx(end1.y) <= approx(intersection.y) <= approx(start1.y):
return None
if not approx(start2.y) <= approx(intersection.y) <= approx(end2.y):
if not approx(end2.y) <= approx(intersection.y) <= approx(start2.y):
return None
return intersection
class Enemy (Entity):
def update(self, game):
#...
if not self.getRect().intersects(game.player.getRect()) and self.canMove():
self.generatePath(game)
if self.path:
# Move towards player
elif self.canMove():
# Hurt the player
#...
def generatePath(self, game):
if not self.lineOccupied(Point(self.x, self.y), game.player.getCenterpoint(), game):
self.path = [game.player.getCenterpoint()]
return
frontier = PriorityQueue()
start = Point(self.x, self.y)
frontier.put(start, 0)
came_from = {}
came_from[start] = None
done = False
while not frontier.empty():
current = frontier.get()
if Rect(current.x + self.hitbox.x, current.y + self.hitbox.y, self.hitbox.w, self.hitbox.h).intersects(game.player.getRect()):
done = True
break
for next in self.findAdjacents(current, game):
if self.lineOccupied(current, next, game): continue
if next not in came_from:
priority = self.heuristic(next, game)
frontier.put(next, priority)
came_from[next] = current
if not done:
self.path.clear()
else:
p = [current]
while came_from[p[-1]] is not None:
p.append(came_from[p[-1]])
self.path = p[::-1][1:]
i = 0
def findAdjacents(self, currentPoint, game):
d = 1 / game.pathfindingGranularity
for x in (currentPoint.x - d, currentPoint.x, currentPoint.x + d):
for y in (currentPoint.y - d, currentPoint.y, currentPoint.y + d):
if x == currentPoint.x and y == currentPoint.y: continue
elif self.canWalkAtCoords(x, y, game):
yield Point(x, y)
def canWalkAtCoords(self, x, y, game):
for nx in (x, x + self.hitbox.w):
for ny in (y, y + self.hitbox.h):
if game.blockAt(nx, ny) != FLOOR:
return False
return True
def lineOccupied(self, start, end, game):
for e in self.room.enemies:
if e is self:
continue
for xo in (self.hitbox.x, self.hitbox.x + self.hitbox.w):
for yo in (self.hitbox.y, self.hitbox.y + self.hitbox.h):
if game.lineInRect(start + Point(xo, yo), end + Point(xo, yo), e.getRect()):
return True
return False
我觉得应该有一个更有效的解决方案,尤其是考虑到房间是矩形的,没有敌人需要四处移动的额外墙壁或障碍物,但到目前为止我正在寻找解决方案空手而归。我可以做一些优化来提高程序的性能吗?或者,如果没有,我应该研究更好的寻路方法吗?任何帮助将不胜感激!
你应该尝试让你的寻路从你的角色开始,然后使用广度优先搜索(对斜率进行一些调整)展开。每次遇到敌人,你都可以计算出它走向玩家的最佳路径。
这样一来,您只需要在整个棋盘上传球一次,而不是针对每个敌人传球一次。
如果您需要更多详细信息,请告诉我。