game_function.py

import sys
import pygame
from alien import Alien
from bullet import Bullet
from time import sleep
from ship import Ship

def check_keydown_events(event, ai_settings, screen, ship, bullets):
    """Respond to key presses."""
    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 key releases."""
    if event.key == pygame.K_RIGHT:
        ship.moving_right = False

    elif event.key == pygame.K_LEFT:
        ship.moving_left = False

def check_play_button(stats, play_button, mouse_x, mouse_y,aliens,bullets,ship,ai_settings,screen):
    button_clicked = play_button.rect.collidepoint(mouse_x, mouse_y)
    if button_clicked and not stats.game_active:
         stats.reset_stats()
         stats.game_active = True
         aliens.empty()
         bullets.empty()
         create_fleet(ai_settings, screen, aliens,ship)
         ship.center_ship()



def check_events(ai_settings, screen, ship, bullets,stats,play_button,aliens):
    """Respond to keyboard and mouse events."""
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        
        elif event.type == pygame.MOUSEBUTTONDOWN:
              mouse_x, mouse_y = pygame.mouse.get_pos()
              check_play_button(stats, play_button, mouse_x, mouse_y,aliens,bullets,ship,ai_settings,screen)

        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,aliens,play_button,stats,sb):
    """Update images on the screen and flip to the new screen."""
    screen.fill(ai_settings.bg_color)
    sb.show_score()
    if  not stats.game_active:
         play_button.draw_button()
    for bullet in bullets.sprites():
        bullet.draw_bullet()
    
    ship.blitme()
    
    aliens.draw(screen)

    pygame.display.flip()

def update_bullets(aliens,bullets,ai_settings,stats,sb):
    collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)
    bullets.update()
    if collisions:
        for aliens in collisions.values():
            stats.score += ai_settings.alien_points * len(aliens)
        
        sb.prep_score()
 # Get rid of bullets that have disappeared.
    for bullet in bullets.copy():
        if bullet.rect.bottom <= 0:
            bullets.remove(bullet)


def fire_bullet(ai_settings, screen, ship, bullets):

 # 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 create_fleet(ai_settings, screen, aliens, ship):
    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
    )

    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 get_number_aliens_x(ai_settings, alien_width):
    available_space_x = ai_settings.screen_width - 2 * alien_width
    number_aliens_x = available_space_x // (2 * alien_width)
    return number_aliens_x


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 get_number_rows(ai_settings, ship_height, alien_height):
    available_space_y = (
        ai_settings.screen_height -
        (3 * alien_height) -
        ship_height
    )

    number_rows = available_space_y // (2 * alien_height)
    return number_rows


def check_fleet_edges(ai_settings, aliens):

    for alien in aliens.sprites():
        if alien.check_edges():
            change_fleet_direction(ai_settings, aliens)
            break

def change_fleet_direction(ai_settings, aliens):
    for alien in aliens.sprites():
        alien.rect.y += ai_settings.fleet_drop_speed

    ai_settings.fleet_direction *= -1

def update_aliens(ai_settings, aliens,stats,screen,bullets,ship):
    check_fleet_edges(ai_settings, aliens)
    aliens.update()
    check_aliens_bottom(ai_settings, stats, screen, ship, aliens, bullets)
    # Look for alien-ship collisions.
    if pygame.sprite.spritecollideany(ship, aliens):
        ship_hit(ai_settings, aliens,stats,screen,bullets,ship)
       

def ship_hit(ai_settings, aliens,stats,screen,bullets,ship):
    if stats.ships_left > 0:
 # Decrement ships_left.
        stats.ships_left -= 1

 # Empty the list of aliens and bullets.
        aliens.empty()
        bullets.empty()

 # Create a new fleet and center the ship.
        create_fleet(ai_settings, screen, aliens,ship)
        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, ship, aliens, bullets):

    screen_rect = screen.get_rect()
    for alien in aliens.sprites():
        if alien.rect.bottom >= screen_rect.bottom:
         ship_hit(ai_settings, aliens,stats,screen,bullets,ship)
         break