如何更改现有代码，使船不在屏幕底部，而是放在屏幕左侧，同时仍允许玩家上下移动船只。船仍然需要能够发射，但子弹需要穿过屏幕而不是向上，因为船不再在屏幕的底部。此外，我需要确保一旦子弹从屏幕上消失就删除它们。这是我的代码。
Alien Invasion 5.py 导入pygame
from pygame.sprite import Group
from settings import Settings
from ship import Ship
import game_functions as gf
def run_game():
# Initialize pygame, settings, and screen object.
pygame.init()
ai_settings = Settings()
screen = pygame.display.set_mode(
(ai_settings.screen_width, ai_settings.screen_height))
pygame.display.set_caption("Alien Invasion")
# Make a ship.
ship = Ship(ai_settings, screen)
# Make a group to store bullets in.
bullets = Group()
# Start the main loop for the game.
while True:
gf.check_events(ai_settings, screen, ship, bullets)
ship.update()
gf.update_bullets(bullets)
gf.update_screen(ai_settings, screen, ship, bullets)
run_game()
game_functions.py
import sys
import pygame
from bullet import Bullet
def check_keydown_events(event, ai_settings, screen, ship, bullets):
"""Respond to keypresses."""
if event.key == pygame.K_RIGHT:
ship.moving_right = True
elif event.key == pygame.K_LEFT:
ship.moving_left = True
elif event.key == pygame.K_SPACE:
fire_bullet(ai_settings, screen, ship, bullets)
def fire_bullet(ai_settings, screen, ship, bullets):
"""Fire a bullet if limit not reached yet."""
# Create a new bullet and add it to the bullets group.
if len(bullets) < ai_settings.bullets_allowed:
new_bullet = Bullet(ai_settings, screen, ship)
bullets.add(new_bullet)
def check_keyup_events(event, ship):
"""Respond to key releases."""
if event.key == pygame.K_RIGHT:
ship.moving_right = False
elif event.key == pygame.K_LEFT:
ship.moving_left = False
def check_events(ai_settings, screen, ship, bullets):
"""Respond to keypresses and mouse events."""
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
elif event.type == pygame.KEYDOWN:
check_keydown_events(event, ai_settings, screen, ship, bullets)
elif event.type == pygame.KEYUP:
check_keyup_events(event, ship)
def update_screen(ai_settings, screen, ship, bullets):
"""Update images on the screen and flip to the new screen."""
# Redraw the screen during each pass through the loop.
screen.fill(ai_settings.bg_color)
# Redraw all bullets behind the ship and aliens.
for bullet in bullets.sprites():
bullet.draw_bullet()
ship.blitme()
def update_bullets(bullets):
"""Update position of bullets and get rid of old bullets."""
# Update bullet positions.
bullets.update()
# Get rid of bullets that have disappeared.
for bullet in bullets.copy():
if bullet.rect.bottom <=0:
bullets.remove(bullet)
# Make the most recently drawn screen visible.
pygame.display.flip()
settings.py
类设置（）： msgstr“”“用于存储Alien Invasion的所有设置的类。”“”
def __init__(self):
"""Initialize the game's settings."""
# Screen settings
self.screen_width = 1200
self.screen_height = 800
self.bg_color = (230,230,230)
# Ship settings
self.ship_speed_factor = 1.5
# Bullet settings
self.bullet_speed_factor = 1
self.bullet_width = 3
self.bullet_height = 15
self.bullet_color = 60,60,60
self.bullets_allowed = 3
bullet.py
导入pygame 来自pygame.sprite导入精灵
class Bullet（精灵）： “”用于管理从他发射的子弹射击的类“”
def __init__(self, ai_settings, screen, ship):
"""Create a bullet object at the ship's current position."""
super(Bullet, self).__init__()
self.screen = screen
# Create a bullet rect at (0,0) and then set correct position.
self.rect = pygame.Rect(0,0, ai_settings.bullet_width,
ai_settings.bullet_height)
self.rect.centerx = ship.rect.centerx
self.rect.top = ship.rect.top
# Store the bullet's position as a decimal value.
self.y = float(self.rect.y)
self.color = ai_settings.bullet_color
self.speed_factor = ai_settings.bullet_speed_factor
def update(self):
"""Move the bullet up the screen."""
# Update the decimal position of the bullet.
self.y -= self.speed_factor
# Update the rect position.
self.rect.y = self.y
def draw_bullet(self):
"""Draw the bullet to the screen."""
pygame.draw.rect(self.screen, self.color, self.rect)
答案 0 :(得分：0)
def update_bullets(bullets):
"""Update position of bullets and get rid of old bullets."""
# Update bullet positions.
bullets.update()
# Get rid of bullets that have disappeared.
for bullet in bullets.copy():
if bullet.rect.bottom <=0:
bullets.remove(bullet)
您将必须插入另一个参数ai_settings，以确保当子弹穿过屏幕宽度时将其删除。 试试这个，它应该可以工作：
def update_bullets(bullets,ai_settings):
"""Update the position of bullets and get rid of the old bullets."""
#Update bullet positions.
bullets.update()
ai_settings = Settings()
#Get rid of bullets that have disappeared.
for bullet in bullets.copy():
if bullet.rect.x >ai_settings.screen_width:
bullets.remove(bullet)
答案 1 :(得分：0)
我相信以下内容可以更好地说明用于“ Python速成课程”问题12-5的项目符号类。
import pygame
# The name used to create the .py where settings are stored
from problem123settings import Settings
ai_settings = Settings()
# Allow the grouping of related elements of the game and act on all the
# grouped elements of the game at once with Sprite.
from pygame.sprite import Sprite
class Bullet(Sprite):
"""A class to manage bullets fired from the ship."""
def __init__(self, ai_settings, screen, ship):
"""Create a bullet object at the ship's current position."""
# Super is called to inherit properly from Sprite.
super().__init__()
self.screen = screen
# Create a bullet rect at (0, 0) [x and y coordinates at the top left
# corner of the screen] and then set the correct position.
self.rect = pygame.Rect(0, 0, ai_settings.bullet_width,
ai_settings.bullet_height)
# Set bullet's centerx at the center of the ship.
self.rect.centerx = ship.rect.centerx
# Set the bullet height at the center of the ship, therefore
# making it appear that the bullet comes from the front of the ship.
self.rect.center = ship.rect.center
# Store the bullet's position as a decimal value.
self.x = float(self.rect.x)
self.color = ai_settings.bullet_color
self.speed_factor = ai_settings.bullet_speed_factor
def update(self):
"""Move the bullet across the screen."""
'''
The update() method manages the bullets position. When a bullet is
fired, it moves across the screen, which corresponds to an increasing
x-coordinate value; so to update the position, we add the amount
stored in self.speed_factor to self.x. We then use the value of
self.x to set the value of self.rect.x. Once fired the bullets
y-coordinate value never changes.
'''
self.x += self.speed_factor
# Update the rect position of the bullet.
self.rect.x = self.x
def draw_bullet(self):
"""Draw the bullet to the screen."""
pygame.draw.rect(self.screen, self.color, self.rect)