在 pygame python 中移动敌人

问题描述

我刚刚在“draw_enemy”方法中添加了 5 行代码，从第 86 行到第 91 行，但现在出现以下错误：文件“/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/random.py”，第 243 行，在 _randbelow_with_getrandbits k = n.bit_length() # 这里不要使用 (n-1) 因为 n 可以是 1 RecursionError：调用 Python 对象时超出了最大递归深度。我不明白这个问题。

import pygame,sys
import random
import time
pygame.init()

clock = pygame.time.Clock()
time0 = time.time()

has_passed = False

screen_width = 600
screen_height = 800

enemyWidth = 30
enemyHeight = 10

bg_color = (94,50,50)
enemy_color = (0,0)

screen = pygame.display.set_mode((screen_width,screen_height))
pygame.display.set_caption("Space Race Game")

class ROCKET:
    def __init__(self):
        self.rocketImg = pygame.image.load("spaceship.png")
        self.rocket_x = screen_width/2 - 32
        self.rocket_y = screen_height/2 + 150

    def draw_rocket(self):
        screen.blit(self.rocketImg,(self.rocket_x,self.rocket_y))

    def move_rocket(self):
        key = pygame.key.get_pressed()

        if key[pygame.K_LEFT] and self.rocket_x + 15 > 0:
            self.rocket_x -= 5

        if key[pygame.K_RIGHT] and self.rocket_x < screen_width - 40:
            self.rocket_x += 5

class BULLET(ROCKET):
    def __init__(self):
        super().__init__()
        self.bullet_width = 10
        self.bullet_height = 20
        self.bullet_x = self.rocket_x + 25
        self.bullet_y = self.rocket_y
        self.move = [0,0]
        self.bullet_speed = 7
        self.bullet_rect = pygame.Rect(self.bullet_x,self.bullet_y,self.bullet_width,self.bullet_height)

    def draw_bullet(self,rocket,bullet):
        key = pygame.key.get_pressed()

        if key[pygame.K_SPACE] and self.move[1] == 0:
            self.bullet_x = rocket.rocket_x + 25
            self.move[1] = -1

        self.bullet_y += self.move[1] * self.bullet_speed
        self.bullet_rect.topleft = (self.bullet_x,self.bullet_y)

        if self.bullet_y < self.rocket_y - 10:
            pygame.draw.rect(screen,(0,0),self.bullet_rect)

        if self.bullet_y < - 20:
            self.bullet_y = self.rocket_y
            self.move[1] = 0

class ENEMY(ROCKET):
    def __init__(self):
        super().__init__()
        self.enemy_width = enemyWidth
        self.enemy_height = enemyHeight
        self.enemy_x = random.randint(self.enemy_width,screen_width - self.enemy_width)
        self.enemy_y = 0
        self.enemy_speed = 1
        self.enemy_rect = pygame.Rect(self.enemy_x,self.enemy_y,self.enemy_width,self.enemy_height)
        self.next_enemy_time = 0
        self.enemies = []

    def draw_enemy(self,bullet):
        pygame.draw.rect(screen,enemy_color,self.enemy_rect)
        self.enemy_y += self.enemy_speed
        self.enemy_rect.topleft = (self.enemy_x,self.enemy_y)
        # Time Management and multiple enemies
        current_time = pygame.time.get_ticks()
        if current_time > self.next_enemy_time:
            self.next_enemy_time = current_time + 3000
            self.enemies.append(ENEMY())
        for enemies in self.enemies:
            enemies.draw_enemy(rocket,bullet)


rocket = ROCKET()
bullet = BULLET()
enemy = ENEMY()

while True:

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    screen.fill(bg_color)
    rocket.draw_rocket()
    rocket.move_rocket()
    bullet.draw_bullet(rocket,bullet)
    enemy.draw_enemy(rocket,bullet)


    pygame.display.flip()
    clock.tick(60)

解决方法

问题可能出在这里：

def draw_enemy(self,rocket,bullet):
        pygame.draw.rect(screen,enemy_color,self.enemy_rect)
        self.enemy_y += self.enemy_speed
        self.enemy_rect.topleft = (self.enemy_x,self.enemy_y)
        # Time Management and multiple enemies
        current_time = pygame.time.get_ticks()
        if current_time > self.next_enemy_time:
            self.next_enemy_time = current_time + 3000
            self.enemies.append(ENEMY())
        for enemies in self.enemies:
            enemies.draw_enemy(rocket,bullet)

特别是这里：

for enemies in self.enemies:
    enemies.draw_enemy(rocket,bullet)

您正在为添加到列表中的每个敌人再次调用 draw_enemy。这反过来又为每个新敌人增加了敌人

if current_time > self.next_enemy_time:
    self.next_enemy_time = current_time + 3000
    self.enemies.append(ENEMY())

并再次对这些调用 draw_enemy：

for enemies in self.enemies:
    enemies.draw_enemy(rocket,bullet)

所以这个函数无限递归，即 draw_enemy 总是调用自己，当达到递归限制时会导致 RecursionError。

您需要添加一个 base case：在某个时候您应该停止添加敌人，或者您应该停止绘制它们。

pygame python