我正在制作外星人入侵游戏。在屏幕上移动了外星人的舰队之后，我应用了碰撞属性，但是当两个对象碰撞（子弹与外星人碰撞）时，剩余的外星人不会出现在屏幕上。
settings.py文件包含代码中将使用的大多数变量。
alien.py包含外来对象的属性。
ship.py文件包含飞船属性和与其相关的功能。
bullet.py
import pygame
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(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)
ship.py
import pygame
class Ship():
def __init__(self, ai_settings, screen):
""" Initialize the ship and set it's starting position. """
self.screen = screen
self.ai_settings = ai_settings
# Load the ship and get it's rect
self.image = pygame.image.load("images\ship.bmp" )
self.rect = self.image.get_rect()
self.screen_rect = screen.get_rect()
# start each new ship at the bottom center of the screen.
self.rect.centerx = self.screen_rect.centerx
self.rect.bottom = self.screen_rect.bottom
# Store a decimal value for the ship's center.
self.center = float(self.rect.centerx)
# Movement flag
self.moving_right = False
self.moving_left = False
def update(self):
""" Update the ship's position based on the movement flag. """
# Update the ship's center value, not the rect.
if self.moving_right and self.rect.right < self.screen_rect.right:
self.center += self.ai_settings.ship_speed_factor
if self.moving_left and self.rect.left > 0:
self.center -= self.ai_settings.ship_speed_factor
# Update rect object from self.center.
self.rect.centerx = self.center
def blitem(self):
""" Draw the ship at it's current location. """
self.screen.blit(self.image, self.rect)
alien.py
import pygame
from pygame.sprite import Sprite
class Alien(Sprite):
""" A class to represent a single alien in the fleet. """
def __init__(self, ai_settings, screen):
""" Initialize the alien and set its starting position. """
super(Alien, self).__init__()
self.screen = screen
self.ai_settings = ai_settings
#Load the alien image and set its rect attribute.
self.image = pygame.image.load("images/alien.bmp")
self.rect = self.image.get_rect()
#Start each new alien near the top left of the screen.
self.rect.x = self.rect.width
self.rect.y = self.rect.height
#Store the alien exact positioon
self.x = float(self.rect.x)
def blitem(self):
""" Draw the alien at its current location. """
self.screen.blit(self.image, self.rect)
def update(self):
""" Move the alien right or left. """
self.x += (self.ai_settings.alien_speed_factor * self.ai_settings.fleet_direction)
self.rect.x = self.x
def check_edges(self):
""" Return True if alien is at edge of screen. """
screen_rect = self.screen.get_rect()
if self.rect.right >= screen_rect.right:
return True
elif self.rect.left <= 0:
return True
settings.py
class Settings():
""" A class to store all the settings of Alien Invasion. """
def __init__(self):
""" Initialize the game settings. """
# Screen settings
self.screen_width = 1200
self.screen_height = 680
self.bg_color = (230,230,230)
# Ship settings
self.ship_speed_factor = 1.5
# Bullet settings
self.bullet_speed_factor = 3
self.bullet_width = 5
self.bullet_height = 15
self.bullet_color = 60, 60, 60
self.bullets_allowed = 3
#Alien Settins
self.alien_speed_factor = 1
self.fleet_drop_speed = 10
# Fleet direction of 1 represent right ; -1 represent left
self.fleet_direction = 1
game_functions.py
import sys
import pygame
from bullet import Bullet
from alien import Alien
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)
elif event.key == pygame.K_q:
sys.exit()
def check_keyup_events(event, ship):
""" Respond to keyreleases. """
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 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 update_bullets(ai_settings, screen, ship, aliens, bullets):
""" Update position of bullets and get rid of old bullets. """
# Update bullet position
bullets.update()
# Get rid of bullets that have disappeared.
for bullet in bullets.copy():
if bullet.rect.bottom <= 0:
bullets.remove(bullet)
# check for any bullets that have hit the alien.
# If so, get rid of the alien and the bullet.
check_bullet_alien_collision(ai_settings, screen, ship, aliens, bullets)
def check_bullet_alien_collision(ai_settings, screen, ship, aliens, bullets):
""" Respond to bullet alien collision. """
# Remove any bullets and aliens that have collided.
collision = pygame.sprite.groupcollide(bullets, aliens, True, True)
if len(aliens) == 0:
print("something bad")
# Destroy existing bullets and create new fleet.
bullets.empty()
create_fleet(ai_settings, screen, ship, aliens)
def update_screen(ai_settings, screen, ship, aliens, bullets):
""" Update images on the screen and flip to the new screen. """
# Redraw the screen during the each pass through the loop.
screen.fill(ai_settings.bg_color)
# Redraw all bullets behind ship and aliens.
for bullet in bullets.sprites():
bullet.draw_bullet()
ship.blitem()
aliens.draw(screen)
# Make the most recently drawn screen visible.
pygame.display.flip()
def get_number_aliens_x(ai_settings, alien_width):
""" Determine the number of aliens that fit in a row. """
available_space_x = ai_settings.screen_width - (2 * alien_width)
number_aliens_x = int(available_space_x / (2 * alien_width))
return number_aliens_x
def get_number_rows(ai_settings, ship_height, alien_height):
""" Determine the number of rows of aliens that fit on the screen. """
available_space_y = (ai_settings.screen_height - (3 * alien_height) - ship_height)
number_rows = int(available_space_y / (2 * alien_height))
return number_rows
def create_alien(ai_settings, screen, aliens, alien_number, row_number):
""" Create an alien and place it in the row. """
alien = Alien(ai_settings, screen)
alien_width = alien.rect.width
alien.x = alien_width + (2 * alien_width * alien_number)
alien.rect.x = alien.x
alien.rect.y = alien.rect.height + (2 * alien.rect.height * row_number)
aliens.add(alien)
def create_fleet(ai_settings, screen, ship, aliens):
""" Create a full fleet of aliens. """
#Create an alien and find the number of aliens in a row.
alien = Alien(ai_settings, screen)
number_aliens_x = get_number_aliens_x(ai_settings, alien.rect.width)
number_rows = get_number_rows(ai_settings, ship.rect.height, alien.rect.height)
# Create the fleet of aliens
for row_number in range(number_rows):
for alien_number in range(number_aliens_x):
# Create an alien and place it in the row.
create_alien(ai_settings, screen, aliens, alien_number, row_number)
def update_aliens(ai_settings, aliens):
""" Check if the fleet is at an edge,
and then update the position of all aliens in the fleet."""
check_fleet_edges(ai_settings, aliens)
aliens.update()
def check_fleet_edges(ai_settings, aliens):
""" Respond appropriately if any alien have reached an edge. """
for alien in aliens.sprites():
if alien.check_edges():
change_fleet_direction(ai_settings, aliens)
break
def change_fleet_direction(ai_settings, aliens):
""" Drop the entire fleet and change the fleet's direction. """
for alien in aliens.sprites():
alien.rect.y += ai_settings.fleet_drop_speed
ai_settings.fleet_direction *= -1
alien_invasion.py
import 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 objects.
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, a group of bullets, and a group of aliens.
ship = Ship(ai_settings, screen)
bullets = Group()
aliens = Group()
#Create the fleet of aliens.
gf.create_fleet(ai_settings, screen, ship, aliens)
# Start the main loop for the game.
while True:
# Watch for keyboard and mouse events.
gf.check_events(ai_settings, screen, ship, bullets)
ship.update()
collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)
gf.update_bullets(ai_settings, screen, ship, aliens, bullets)
gf.update_aliens(ai_settings, aliens)
gf.update_screen(ai_settings, screen, ship, aliens, bullets)
run_game()