Pygame-零除错误:零除以浮点数

时间:2018-09-10 20:32:31

标签: python pygame

我去了Stack Overflow,读了一种算法,该算法使敌人追随玩家。它曾经工作过,但现在却引发了零除错误。我了解这是因为python被0除(意味着它们之间的距离为0),但是,我不明白为什么以前抛出该错误,即使两者之间的距离为0,也没有抛出该错误。有人澄清吗?

import pygame
import math

pygame.init()
width, height = 800, 600
white = (255, 255, 255)

class Enemy(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface((40, 50))
        self.image.fill(white)
        self.rect = self.image.get_rect()
        self.rect.x = width / 2
        self.rect.y = height/ 2
        self.speed = 1


    def move_towards_another_object(self):
        self.dx = self.rect.x - player.rect.x
        self.dy = self.rect.y - player.rect.y
        self.dist = math.hypot(self.dx, self.dy)
        self.dx = self.dx/self.dist
        self.dy = self.dy/self.dist
        self.rect.x += self.dx * -self.speed
        self.rect.y += self.dy * -self.speed

enemy = Enemy()

class Player(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface((50, 40))
        self.image.fill(white)
        self.rect = self.image.get_rect()
        self.rect.x = 0 + self.rect.x
        self.rect.y = height - self.rect.height

player = Player()

all_sprites = pygame.sprite.Group()
all_sprites.add(enemy, player)
gameExit = False

while not gameExit:
    enemy.move_towards_another_object()

pygame.quit()
quit()

2 个答案:

答案 0 :(得分:1)

您的enemy精灵在每次迭代时朝着player迈出一个单位步长。最终,它与播放器完全重合,并且self.dist是一个完美的0。您的坐标为 integers ,因此不难得出准确的数学结果。在以前的版本中,坐标是否浮动?可以很容易地解释差异。

答案 1 :(得分:0)

我用这段代码修复了它:

def move_towards_another_object(self):
    self.dx = self.rect.x - player.rect.x
    self.dy = self.rect.y - player.rect.y
    self.dist = math.hypot(self.dx, self.dy)
    if self.dist == 0:
        self.rect.x = self.rect.x
        self.rect.y = self.rect.y
    else:
        self.dx = self.dx/self.dist
        self.dy = self.dy/self.dist
        self.rect.x += self.dx * -self.speed
        self.rect.y += self.dy * -self.speed