Alien not defined - python-3.x

Question

For some reason, the python window says Alien not defined.
alien.py:
import pygame
from pygame.sprite import Sprite
class Alien(Sprite):
def __init__(self, ai_settings, screen):
super(Alien, self).__init__()
self.screen = screen
self.ai_settings = ai_settings
self.image = pygame.image.load('alien.bmp')
self.rect = self.image.get_rect()
self.rect.x = self.rect.width
self.rect.y = self.rect.height
self.x = float(self.rect.x)
def check_edges(self):
screen_rect = self.screen.get_rect()
if self.rect.right >= screen_rect.right:
return True
elif self.rect.left <= 0:
return True
def update(self):
self.x += (self.ai_settings.alien_speed_factor *
self.ai_settings.fleet_direction)
self.rect.x = self.x
def blitme(self):
self.screen.blit(self.image, self.rect)
alien_invasion.py:
import sys
import pygame
from settings import Settings
from ship import Ship
import game_functions as gf
import random
from pygame.sprite import Group
from alien import Alien
class Square(pygame.sprite.Sprite):
def __init__(self, x, y, size1, size2, colour):
super().__init__()
self.image = pygame.Surface([size1, size2])
self.image.fill(colour)
self.rect=self.image.get_rect()
self.rect.x=x
self.rect.y=y
allspriteslist = pygame.sprite.Group()
for i in range(1, 250):
num = random.randint(1,3)
stars = Square(random.randint(0, 1000), random.randint(0, 700), num, num, (255, 255, 255))
allspriteslist.add(stars)
def run_game():
pygame.init()
ai_settings = Settings()
screen = pygame.display.set_mode((ai_settings.screen_width, ai_settings.screen_height))
pygame.display.set_caption("PEWPEWPEWPOWPOW DIE YOU LITTLE ALIEN ____S ")
ship = Ship(ai_settings, screen)
bullets = Group()
aliens = Group()
gf.create_fleet(ai_settings, screen, ship, aliens)
while True:
gf.check_events(ai_settings, screen, ship, bullets)
ship.update()
gf.update_bullets(bullets)
gf.update_screen(ai_settings, screen, ship, alien, bullets)
allspriteslist.draw(screen)
pygame.display.flip()
run_game()
bullet.py:
import pygame
from pygame.sprite import Sprite
class Bullet(Sprite):
def __init__(self, ai_settings, screen, ship):
super(Bullet, self).__init__()
self.screen = screen
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
self.y = float(self.rect.y)
self.color = ai_settings.bullet_color
self.speed_factor = ai_settings.bullet_speed_factor
def update(self):
self.y -= self.speed_factor
self.rect.y = self.y
def draw_bullet(self):
pygame.draw.rect(self.screen, self.color, self.rect)
game_functions.py:
import sys
import pygame
from bullet import Bullet
def check_keydown_events(event, ai_settings, screen, ship, bullets):
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):
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):
for event in pygame.event.get():
if event == 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, aliens, bullets):
screen.fill(ai_settings.bg_colour)
for bullet in bullets.sprites():
bullet.draw_bullet()
ship.blitme()
aliens.draw(screen)
def update_bullets(bullets):
bullets.update()
for bullet in bullets.copy():
if bullet.rect.bottom <= 0:
bullets.remove(bullet)
def fire_bullet(ai_settings, screen, ship, bullets):
if len(bullets) < ai_settings.bullets_allowed:
new_bullet = Bullet(ai_settings, screen, ship)
bullets.add(new_bullet)
def get_number_rows(ai_settings, ship_height, alien_height):
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):
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):
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)
settings.py:
class Settings():
def __init__(self):
#screen stuff
self.screen_width = 1000
self.screen_height = 750
self.bg_colour = (0, 0, 0)
self.ship_speed_factor = 1.5
self.bullet_speed_factor = 1
self.bullet_width = 3
self.bullet_height = 15
self.bullet_color = 0, 255, 0
self.bullets_allowed = 7
ship.py:
import pygame
class Ship():
def __init__(self, ai_settings, screen):
self.screen = screen
self.ai_settings = ai_settings
self.image = pygame.image.load('ship.bmp')
self.rect = self.image.get_rect()
self.screen_rect = screen.get_rect()
self.rect.centerx = self.screen_rect.centerx
self.rect.bottom = self.screen_rect.bottom
self.moving_right = False
self.moving_left = False
self.center = float(self.rect.centerx)
def update(self):
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
self.rect.centerx = self.center
def blitme(self):
self.screen.blit(self.image, self.rect)
I'm getting an error message that Alien is not defined when I run this code, and I don't know why.

Answer 1

How is the game_functions.py file meant to know about the Alien it uses in createAlien() and createFleet()?
Python is good, but it can't read minds :-) I think you probably need to import the alien stuff into that file.