Code for How to Create a Space Invaders Game in Python Tutorial

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alien.py

import pygame from settings import BULLET_SIZE from bullet import Bullet class Alien(pygame.sprite.Sprite): def __init__(self, pos, size, row_num): super().__init__() self.x = pos[0] self.y = pos[1] # alien info img_path = f'assets/aliens/{row_num}.png' self.image = pygame.image.load(img_path) self.image = pygame.transform.scale(self.image, (size, size)) self.rect = self.image.get_rect(topleft = pos) self.mask = pygame.mask.from_surface(self.image) self.move_speed = 5 self.to_direction = "right" # alien status self.bullets = pygame.sprite.GroupSingle() def move_left(self): self.rect.x -= self.move_speed def move_right(self): self.rect.x += self.move_speed def move_bottom(self): self.rect.y += self.move_speed def _shoot(self): specific_pos = (self.rect.centerx - (BULLET_SIZE // 2), self.rect.centery) self.bullets.add(Bullet(specific_pos, BULLET_SIZE, "enemy")) def update(self): self.rect = self.image.get_rect(topleft=(self.rect.x, self.rect.y))

bullet.py

import pygame from settings import BULLET_SPEED, HEIGHT class Bullet(pygame.sprite.Sprite): def __init__(self, pos, size, side): super().__init__() self.x = pos[0] self.y = pos[1] # bullet info img_path = f'assets/bullet/{side}-bullet.png' self.image = pygame.image.load(img_path) self.image = pygame.transform.scale(self.image, (size, size)) self.rect = self.image.get_rect(topleft = pos) self.mask = pygame.mask.from_surface(self.image) # different bullet movement direction for both player and enemy (alien) if side == "enemy": self.move_speed = BULLET_SPEED elif side == "player": self.move_speed = (- BULLET_SPEED) def _move_bullet(self): self.rect.y += self.move_speed def update(self): self._move_bullet() self.rect = self.image.get_rect(topleft=(self.rect.x, self.rect.y)) # delete the bullet if it get through out of the screen if self.rect.bottom <= 0 or self.rect.top >= HEIGHT: self.kill()

display.py

import pygame from settings import WIDTH, HEIGHT, SPACE, FONT_SIZE, EVENT_FONT_SIZE pygame.font.init() class Display: def __init__(self, screen): self.screen = screen self.score_font = pygame.font.SysFont("monospace", FONT_SIZE) self.level_font = pygame.font.SysFont("impact", FONT_SIZE) self.event_font = pygame.font.SysFont("impact", EVENT_FONT_SIZE) self.text_color = pygame.Color("blue") self.event_color = pygame.Color("red") def show_life(self, life): life_size = 30 img_path = "assets/life/life.png" life_image = pygame.image.load(img_path) life_image = pygame.transform.scale(life_image, (life_size, life_size)) life_x = SPACE // 2 if life != 0: for life in range(life): self.screen.blit(life_image, (life_x, HEIGHT + (SPACE // 2))) life_x += life_size def show_score(self, score): score_x = WIDTH // 3 score = self.score_font.render(f'score: {score}', True, self.text_color) self.screen.blit(score, (score_x, (HEIGHT + (SPACE // 2)))) def show_level(self, level): level_x = WIDTH // 3 level = self.level_font.render(f'Level {level}', True, self.text_color) self.screen.blit(level, (level_x * 2, (HEIGHT + (SPACE // 2)))) def game_over_message(self): message = self.event_font.render('GAME OVER!!', True, self.event_color) self.screen.blit(message, ((WIDTH // 3) - (EVENT_FONT_SIZE // 2), (HEIGHT // 2) - (EVENT_FONT_SIZE // 2)))

main.py

import pygame, sys from settings import WIDTH, HEIGHT, NAV_THICKNESS from world import World pygame.init() screen = pygame.display.set_mode((WIDTH, HEIGHT + NAV_THICKNESS)) pygame.display.set_caption("Space Invader") class Main: def __init__(self, screen): self.screen = screen self.FPS = pygame.time.Clock() def main(self): world = World(self.screen) while True: self.screen.fill("black") for event in pygame.event.get(): if event.type == pygame.QUIT: pygame.quit() sys.exit() if event.type == pygame.KEYDOWN: if event.key == pygame.K_SPACE: world.player_move(attack = True) world.player_move() world.update() pygame.display.update() self.FPS.tick(30) if __name__ == "__main__": play = Main(screen) play.main()

settings.py

WIDTH, HEIGHT = 720, 450 SPACE = 30 FONT_SIZE = 20 EVENT_FONT_SIZE = 60 NAV_THICKNESS = 50 CHARACTER_SIZE = 30 PLAYER_SPEED = 10 ENEMY_SPEED = 1 BULLET_SPEED = 15 # for both sides BULLET_SIZE = 10

ship.py

import pygame from settings import PLAYER_SPEED, BULLET_SIZE from bullet import Bullet class Ship(pygame.sprite.Sprite): def __init__(self, pos, size): super().__init__() self.x = pos[0] self.y = pos[1] # ship info img_path = 'assets/ship/ship.png' self.image = pygame.image.load(img_path) self.image = pygame.transform.scale(self.image, (size, size)) self.rect = self.image.get_rect(topleft = pos) self.mask = pygame.mask.from_surface(self.image) self.ship_speed = PLAYER_SPEED # ship status self.life = 3 self.player_bullets = pygame.sprite.Group() def move_left(self): self.rect.x -= self.ship_speed def move_up(self): self.rect.y -= self.ship_speed def move_right(self): self.rect.x += self.ship_speed def move_bottom(self): self.rect.y += self.ship_speed def _shoot(self): specific_pos = (self.rect.centerx - (BULLET_SIZE // 2), self.rect.y) self.player_bullets.add(Bullet(specific_pos, BULLET_SIZE, "player")) def update(self): self.rect = self.image.get_rect(topleft=(self.rect.x, self.rect.y))

world.py

import pygame from ship import Ship from alien import Alien from settings import HEIGHT, WIDTH, ENEMY_SPEED, CHARACTER_SIZE, BULLET_SIZE, NAV_THICKNESS from bullet import Bullet from display import Display class World: def __init__(self, screen): self.screen = screen self.player = pygame.sprite.GroupSingle() self.aliens = pygame.sprite.Group() self.display = Display(self.screen) self.game_over = False self.player_score = 0 self.game_level = 1 self._generate_world() def _generate_aliens(self): # generate opponents alien_cols = (WIDTH // CHARACTER_SIZE) // 2 alien_rows = 3 for y in range(alien_rows): for x in range(alien_cols): my_x = CHARACTER_SIZE * x my_y = CHARACTER_SIZE * y specific_pos = (my_x, my_y) self.aliens.add(Alien(specific_pos, CHARACTER_SIZE, y)) # create and add player to the screen def _generate_world(self): # create the player's ship player_x, player_y = WIDTH // 2, HEIGHT - CHARACTER_SIZE center_size = CHARACTER_SIZE // 2 player_pos = (player_x - center_size, player_y) self.player.add(Ship(player_pos, CHARACTER_SIZE)) self._generate_aliens() def add_additionals(self): # add nav bar nav = pygame.Rect(0, HEIGHT, WIDTH, NAV_THICKNESS) pygame.draw.rect(self.screen, pygame.Color("gray"), nav) # render player's life, score and game level self.display.show_life(self.player.sprite.life) self.display.show_score(self.player_score) self.display.show_level(self.game_level) def player_move(self, attack = False): keys = pygame.key.get_pressed() if keys[pygame.K_a] and not self.game_over or keys[pygame.K_LEFT] and not self.game_over: if self.player.sprite.rect.left > 0: self.player.sprite.move_left() if keys[pygame.K_d] and not self.game_over or keys[pygame.K_RIGHT] and not self.game_over: if self.player.sprite.rect.right < WIDTH: self.player.sprite.move_right() if keys[pygame.K_w] and not self.game_over or keys[pygame.K_UP] and not self.game_over: if self.player.sprite.rect.top > 0: self.player.sprite.move_up() if keys[pygame.K_s] and not self.game_over or keys[pygame.K_DOWN] and not self.game_over: if self.player.sprite.rect.bottom < HEIGHT: self.player.sprite.move_bottom() # game restart button if keys[pygame.K_r]: self.game_over = False self.player_score = 0 self.game_level = 1 for alien in self.aliens.sprites(): alien.kill() self._generate_world() if attack and not self.game_over: self.player.sprite._shoot() def _detect_collisions(self): # checks if player bullet hits the enemies (aliens) player_attack_collision = pygame.sprite.groupcollide(self.aliens, self.player.sprite.player_bullets, True, True) if player_attack_collision: self.player_score += 10 # checks if the aliens' bullet hit the player for alien in self.aliens.sprites(): alien_attack_collision = pygame.sprite.groupcollide(alien.bullets, self.player, True, False) if alien_attack_collision: self.player.sprite.life -= 1 break # checks if the aliens hit the player alien_to_player_collision = pygame.sprite.groupcollide(self.aliens, self.player, True, False) if alien_to_player_collision: self.player.sprite.life -= 1 def _alien_movement(self): move_sideward = False move_forward = False for alien in self.aliens.sprites(): if alien.to_direction == "right" and alien.rect.right < WIDTH or alien.to_direction == "left" and alien.rect.left > 0: move_sideward = True move_forward = False else: move_sideward = False move_forward = True alien.to_direction = "left" if alien.to_direction == "right" else "right" break for alien in self.aliens.sprites(): if move_sideward and not move_forward: if alien.to_direction == "right": alien.move_right() if alien.to_direction == "left": alien.move_left() if not move_sideward and move_forward: alien.move_bottom() def _alien_shoot(self): for alien in self.aliens.sprites(): if (WIDTH - alien.rect.x) // CHARACTER_SIZE == (WIDTH - self.player.sprite.rect.x) // CHARACTER_SIZE: alien._shoot() break def _check_game_state(self): # check if game over if self.player.sprite.life <= 0: self.game_over = True self.display.game_over_message() for alien in self.aliens.sprites(): if alien.rect.top >= HEIGHT: self.game_over = True self.display.game_over_message() break # check if next level if len(self.aliens) == 0 and self.player.sprite.life > 0: self.game_level += 1 self._generate_aliens() for alien in self.aliens.sprites(): alien.move_speed += self.game_level - 1 def update(self): # detecting if bullet, alien, and player group is colliding self._detect_collisions() # allows the aliens to move self._alien_movement() # allows alien to shoot the player self._alien_shoot() # bullets rendering self.player.sprite.player_bullets.update() self.player.sprite.player_bullets.draw(self.screen) [alien.bullets.update() for alien in self.aliens.sprites()] [alien.bullets.draw(self.screen) for alien in self.aliens.sprites()] # player ship rendering self.player.update() self.player.draw(self.screen) # alien rendering self.aliens.draw(self.screen) # add nav self.add_additionals() # checks game state self._check_game_state()