pygame.Surface object has no attribute 'prep_ships'

Question

Been trying to figure out what's wrong but I can't seem to find the answer.

Here is the game_functions where the error is located:

    import sys
from time import sleep

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 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, ai_settings, 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, stats, sb, play_button, ship, 
                    aliens, 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, ai_settings, ship)
        elif event.type == pygame.MOUSEBUTTONDOWN:
            mouse_x, mouse_y = pygame.mouse.get_pos()
            check_play_button(ai_settings, screen, stats, sb, play_button, ship, aliens, bullets, mouse_x, mouse_y)
            
def check_play_button(ai_settings, screen, stats, sb, play_button, ship, aliens, bullets, mouse_x, mouse_y):
    """Start a new game when the player clicks Play."""
    button_clicked = play_button.rect.collidepoint(mouse_x, mouse_y)
    if button_clicked and not stats.game_active:
        # Reset the game settings.
        ai_settings.initialize_dynamic_settings()
        
        # Hide the mouse cursor.
        pygame.mouse.set_visible(False)
        # Reset the game statistics.
        stats.reset_stats()
        stats.game_active = True
        
        # Reset the scoreboard images.
        sb.prep_score()
        sb.prep_high_score()
        sb.prep_level()
        sb.prep_ships()
        
        # Empty the list of aliens and bullets.
        aliens.empty()
        bullets.empty()
        
        # Create a new fleet and center the ship.
        create_fleet(ai_settings, screen, ship, aliens)
        ship.center_ship()
            
def update_screen(ai_settings, screen, stats, sb, ship, aliens, bullets, play_button):
    """Update images on the screenand flip to the new screen."""
    # Redraw the screen during 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.blitme()
    aliens.draw(screen)
    # Draw the score information.
    sb.show_score()
    
    # Draw the play button if the game is inactive.
    if not stats.game_active:
        play_button.draw_button()
    
    # Make the most recently drawn screen visible.
    pygame.display.flip()
    
def update_bullets(ai_settings, screen, stats, sb, ship, aliens, bullets):
    """Update position of bullets and get rid of old bullets."""
    # Update bullet positions.
    bullets.update()
    # Get rid of bullets that have dissapeared.
    for bullet in bullets.copy():
        if bullet.rect.bottom <= 0:
            bullets.remove(bullet)
    
    check_bullet_alien_collisions(ai_settings, screen, stats, sb, ship, aliens, bullets)
    
def check_bullet_alien_collisions(ai_settings, screen,stats, sb, ship, aliens, bullets):
    """Respond to bullet-alien collisions."""
    # Remove any bullets and aliens that have collided  
    collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)
    if collisions:
        for aliens in collisions.values():
            stats.score += ai_settings.alien_points * len(aliens)
            sb.prep_score()
        check_high_score(stats, sb)
    
    if len(aliens) == 0:
        # If the entire fleet is destroyed, start a new level.
        bullets.empty()
        ai_settings.increase_speed()
        
        # Increase level.
        stats.level += 1
        sb.prep_level()
        
        create_fleet(ai_settings, screen, ship, aliens)
            
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_alien(ai_settings, screen, aliens, alien_number,
                row_number)
                
def check_fleet_edges(ai_settings, aliens):
    """Respond appropriately if any aliens 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
    
def update_aliens(ai_settings, stats, screen, sb, ship, aliens, bullets):
    """
    Check if the fleet is at an edge, 
       and then update the positions of all aliens in the fleet.
    """
    check_fleet_edges(ai_settings, aliens)
    aliens.update()
    
    # Look for alien-ship collisions.
    if pygame.sprite.spritecollideany(ship, aliens):
        ship_hit(ai_settings,  stats, sb, screen, ship, aliens, bullets)
    
    # Look for aliens hitting the bottom of the screen.
    check_aliens_bottom(ai_settings, stats, screen, sb, ship, aliens, bullets)
    
    
def ship_hit(ai_settings, stats, screen, sb, ship, aliens, bullets):
    """Respond to the ship being hit by an alien."""
    if stats.ships_left > 0:
        # Decrement ships_left.
        stats.ships_left -= 1
        
        # Update scoreboard.
        # HERE IS THE ERROR.
        sb.prep_ships()
    
        # Empty the list of aliens and bullets.
        aliens.empty()
        bullets.empty()
    
        # Create a new fleet and center the ship.
        create_fleet(ai_settings, screen, ship, aliens)
        ship.center_ship()
    
        # Pause.
        sleep(0.5)
        
    else:
        stats.game_active = False
        pygame.mouse.set_visible(True)
                
def check_aliens_bottom(ai_settings, stats, screen, sb, ship, aliens, bullets):
    """Check if any aliens have reached the bottom of the screen."""
    screen_rect = screen.get_rect()
    for alien in aliens.sprites():
        if alien.rect.bottom >= screen_rect.bottom:
            # Treat the same as if the ship got hit.
            ship_hit(ai_settings, stats, screen, sb, ship, aliens, bullets)
            break


def check_high_score(stats, sb):
    """Check to see if there's a new high score."""
    if stats.score > stats.high_score:
        stats.high_score = stats.score
        sb.prep_high_score()

    

Here is scoreboard.py:

class Scoreboard():
    """A class to report scoring information."""
    
    def __init__(self, ai_settings, screen, stats):
        """Initialize scorekeeping attributes."""
        self.screen = screen
        self.screen_rect = screen.get_rect()
        self.ai_settings = ai_settings
        self.stats = stats
        
        # Font settings for scoring information.
        self.text_color = (30, 30, 30)
        self.font = pygame.font.SysFont(None, 48)
        
        # Prepare the initial score images.
        self.prep_score()
        self.prep_high_score()
        self.prep_level()
        self.prep_ships()
        
    def prep_score(self):
        """Turn the score into a rendered image."""
        rounded_score = int(round(self.stats.score, -1))
        score_str = "{:,}".format(rounded_score)
        score_str = str(self.stats.score)
        self.score_image = self.font.render(score_str, True, self.text_color, self.ai_settings.bg_color)
        
        # Display the score at the top right of the screen.
        self.score_rect = self.score_image.get_rect()
        self.score_rect.right = self.screen_rect.right - 20
        self.score_rect.top = 20
        
    def prep_high_score(self):
        """Turn the high score into a rendered image."""
        high_score = int(round(self.stats.high_score, -1))
        high_score_str = "{:,}".format(high_score)
        self.high_score_image = self.font.render(high_score_str, True, self.text_color, self.ai_settings.bg_color)
        
        # Center the high score at the top of the screen.
        self.high_score_rect = self.high_score_image.get_rect()
        self.high_score_rect.centerx = self.screen_rect.centerx
        self.high_score_rect.top = self.score_rect.top
        
    def prep_level(self):
        """Turn the level into a rendered image."""
        self.level_image = self.font.render(str(self.stats.level), True, self.text_color, self.ai_settings.bg_color)
        
        # Position the level below the score.
        self.level_rect = self.level_image.get_rect()
        self.level_rect.right = self.score_rect.right
        self.level_rect.top = self.score_rect.bottom + 10
        
    def prep_ships(self):
        """Show how many ships are left."""
        self.ships = Group()
        for ship_number in range(self.stats.ships_left):
            ship = Ship(self.ai_settings, self.screen)
            ship.rect.x = 10 + ship_number * ship.rect.width
            ship.rect.y = 10
            self.ships.add(ship)
        
    def show_score(self):
        """Draw scores and ships to the screen."""
        self.screen.blit(self.score_image, self.score_rect)
        self.screen.blit(self.high_score_image, self.high_score_rect)
        self.screen.blit(self.level_image, self.level_rect)
        # Draw ships.
        self.ships.draw(self.screen)

here is ship.py:

import pygame from pygame.sprite import Sprite

class Ship(Sprite):

def __init__(self, ai_settings, screen):
    """Initialize the ship and set its starting position."""
    super(Ship, self).__init__()
    self.screen = screen
    self.ai_settings = ai_settings
    
    # Load the ship image and get its 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 flags
    self.moving_right = False
    self.moving_left = False
    
def update(self):
    """Update the ship's position based on movement flags."""
    # 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 blitme(self):
    """Draw the ship at its current location."""
    self.screen.blit(self.image, self.rect)
    
def center_ship(self):
    """Center the ship on the screen."""
    self.center = self.screen_rect.centerx

And here is alien_invasion.py, the code that i run:

import pygame
from pygame.sprite import Group

from settings import Settings
from game_stats import GameStats
from scoreboard import Scoreboard
from button import Button
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 the Play button.
    play_button = Button(ai_settings, screen, "Play")
    
    # Create an instance to store game statistics and create a scoreboard.
    stats = GameStats(ai_settings)
    sb = Scoreboard(ai_settings, screen, stats)
    
    # 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:
        gf.check_events(ai_settings, screen, stats, sb, play_button, ship, aliens, bullets)
        
        if stats.game_active:
            ship.update()
            gf.update_bullets(ai_settings, screen, stats, sb, ship, aliens, bullets)
            gf.update_aliens(ai_settings, stats, screen, sb, ship, aliens, bullets)
            
        gf.update_screen(ai_settings, screen, stats, sb, ship, aliens, bullets, play_button)
                
run_game()
    

This is the error that i keep getting:

 game_functions.py, line 182 in ship_hit
        sb.prep_ships()
    AttribueError: 'pygame.Surface' objecthas no attribute 'prep_ships'

I really can't figure out what's wrong. Not even the rubber duck can help me this time. So some help would be appreciated.

Answer 1

The issue is the line ship_hit(ai_settings, stats, sb, screen, ship, aliens, bullets) in the function update_aliens . In this line the arguments stats and sb are swapped. It has to be:

ship_hit(ai_settings, stats, sb, screen, ship, aliens, bullets)

ship_hit(ai_settings, stats, screen, sb, ship, aliens, bullets)