Game crashing when player2 collides with money. Error message: unboundLocalError: local variable 'score2' referenced before assignment

Question

import random

WIDTH = 800
HEIGHT = 500

background = Actor("background")
player = Actor("player")
enemy = Actor("enemy")
money = Actor("money", pos=(300,300))
player2 = Actor("alien")
score = 0
score2 = 0
player.x = 200
player.y = 200
player2.x= 400
player2.y= 400

def draw():
    screen.clear()
    background.draw()
    player.draw()
    enemy.draw()
    money.draw()
    player2.draw()

def update():
    global score
    if keyboard.right:
        player.x = player.x + 4
    if keyboard.left:
        player.x = player.x - 4
    if keyboard.down:
        player.y = player.y + 4
    if keyboard.up:
        player.y = player.y - 4

    if player.x > WIDTH:
        player.x = WIDTH
    if player.x < 0:
        player.x = 0
    if player.y < 0:
        player.y = 0
    if player.y > HEIGHT:
        player.y = HEIGHT

    if keyboard.d:
        player2.x = player2.x + 4
    if keyboard.a:
        player2.x = player2.x - 4
    if keyboard.s:
        player2.y = player2.y + 4
    if keyboard.w:
        player2.y = player2.y - 4
    if player.colliderect(player2):
        exit()

    if player2.x > WIDTH:
        player2.x = WIDTH
    if player2.x < 0:
        player2.x = 0
    if player2.y < 0:
        player2.y = 0
    if player2.y > HEIGHT:
        player2.y = HEIGHT

    dx1, dy1 = player.x - enemy.x, player.y - enemy.y
    dx2, dy2 = player2.x - enemy.x, player2.y - enemy.y
    dist1sq = dx1*dx1 + dy1*dy1
    dist2sq = dx2*dx2 + dy2*dy2 

    player_near = player if dist1sq < dist2sq else player2

    if enemy.x < player_near.x:
        enemy.x += 1
    if enemy.x > player_near.x:
        enemy.x -= 1
    if enemy.y < player_near.y:
        enemy.y += 1
    if enemy.y > player_near.y:
        enemy.y -= 1
    if player.colliderect(enemy):
        exit()
    if player2.colliderect(enemy):
        exit()

    if money.colliderect(player):
        money.x = random.randint(0, WIDTH)
        money.y = random.randint(0, HEIGHT)
        score = score + 1

    if money.colliderect(player2):
        money.x = random.randint(0, WIDTH)
        money.y = random.randint(0, HEIGHT)
        score2 += 1

    if keyboard.d:
        player2.x = player2.x + 4
    if keyboard.a:
        player2.x = player2.x - 4
    if keyboard.s:
        player2.y = player2.y + 4
    if keyboard.w:
        player2.y = player2.y - 4
    if player.colliderect(player2):
        exit()

    if player2.x > WIDTH:
        player2.x = WIDTH
    if player2.x < 0:
        player2.x = 0
    if player2.y < 0:
        player2.y = 0
    if player2.y > HEIGHT:
        player2.y = HEIGHT

这是一款用 mu editor 制作的 python 游戏。每当 player2 与钱发生碰撞时，player2 应该收集它并获得分数。每当 player2 与金钱发生碰撞时，它就会使游戏崩溃，并给我一个错误消息：UnboundLocalError: local variable 'score2' referenced before assignment.

Answer 1

您错过了申报 gloabl score2:

def update():
    global score, score2 # <----

    # [...]

    if money.colliderect(player2):
        money.x = random.randint(0, WIDTH)
        money.y = random.randint(0, HEIGHT)
        score2 += 1

注意，如果您不将 score2 声明为 global 变量，则 scope2 将被假定为 update 范围内的变量，因为变量设置在 score2 += 1 中。但是，语句 score2 += 1 会导致异常，因为它试图在变量定义之前读取它。

Game crashing when player2 collides with money. Error message: unboundLocalError: local variable 'score2' referenced before assignment

Game crashing when player2 collides with money. Error message: unboundLocalError: local variable 'score2' referenced before assignment

python

pygame

game-development

mu