import sys
from time import sleep
import pygame
from settings import Settings
from game_stats import GameStats
from scoreboard import Scoreboard
from button import Button
from ship import Ship
from bullet import Bullet
from alien import Alien
class AlienInvasion:
"""Overall class to manage game assets and behavior."""
def __init__(self):
"""Initialize the game, and create game resources."""
pygame.init()
self.clock = pygame.time.Clock()
self.settings = Settings()
self.screen = pygame.display.set_mode(
(self.settings.screen_width, self.settings.screen_height))
pygame.display.set_caption("Alien Invasion")
# Create an instance to store game statistics,
# and create a scoreboard.
self.stats = GameStats(self)
self.sb = Scoreboard(self)
self.ship = Ship(self)
self.bullets = pygame.sprite.Group()
self.aliens = pygame.sprite.Group()
self._create_fleet()
# Start Alien Invasion in an inactive state.
self.game_active = False
# Make the Play button.
self.play_button = Button(self, "Play")
def run_game(self):
"""Start the main loop for the game."""
while True:
self._check_events()
if self.game_active:
self.ship.update()
self._update_bullets()
self._update_aliens()
self._update_screen()
self.clock.tick(60)
def _check_events(self):
"""Respond to keypresses and mouse events."""
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
elif event.type == pygame.KEYDOWN:
self._check_keydown_events(event)
elif event.type == pygame.KEYUP:
self._check_keyup_events(event)
elif event.type == pygame.MOUSEBUTTONDOWN:
mouse_pos = pygame.mouse.get_pos()
self._check_play_button(mouse_pos)
def _check_play_button(self, mouse_pos):
"""Start a new game when the player clicks Play."""
button_clicked = self.play_button.rect.collidepoint(mouse_pos)
if button_clicked and not self.game_active:
# Reset the game settings.
self.settings.initialize_dynamic_settings()
# Reset the game statistics.
self.stats.reset_stats()
self.sb.prep_score()
self.sb.prep_level()
self.sb.prep_ships()
self.game_active = True
# Get rid of any remaining bullets and aliens.
self.bullets.empty()
self.aliens.empty()
# Create a new fleet and center the ship.
self._create_fleet()
self.ship.center_ship()
# Hide the mouse cursor.
pygame.mouse.set_visible(False)
def _check_keydown_events(self, event):
"""Respond to keypresses."""
if event.key == pygame.K_RIGHT:
self.ship.moving_right = True
elif event.key == pygame.K_LEFT:
self.ship.moving_left = True
elif event.key == pygame.K_q:
sys.exit()
elif event.key == pygame.K_SPACE:
self._fire_bullet()
def _check_keyup_events(self, event):
"""Respond to key releases."""
if event.key == pygame.K_RIGHT:
self.ship.moving_right = False
elif event.key == pygame.K_LEFT:
self.ship.moving_left = False
def _fire_bullet(self):
"""Create a new bullet and add it to the bullets group."""
if len(self.bullets) < self.settings.bullets_allowed:
new_bullet = Bullet(self)
self.bullets.add(new_bullet)
def _update_bullets(self):
"""Update position of bullets and get rid of old bullets."""
# Update bullet positions.
self.bullets.update()
# Get rid of bullets that have disappeared.
for bullet in self.bullets.copy():
if bullet.rect.bottom <= 0:
self.bullets.remove(bullet)
self._check_bullet_alien_collisions()
def _check_bullet_alien_collisions(self):
"""Respond to bullet-alien collisions."""
# Remove any bullets and aliens that have collided.
collisions = pygame.sprite.groupcollide(
self.bullets, self.aliens, True, True)
if collisions:
for aliens in collisions.values():
self.stats.score += self.settings.alien_points * len(aliens)
self.sb.prep_score()
self.sb.check_high_score()
if not self.aliens:
# Destroy existing bullets and create new fleet.
self.bullets.empty()
self._create_fleet()
self.settings.increase_speed()
# Increase level.
self.stats.level += 1
self.sb.prep_level()
def _ship_hit(self):
"""Respond to the ship being hit by an alien."""
if self.stats.ships_left > 0:
# Decrement ships_left, and update scoreboard.
self.stats.ships_left -= 1
self.sb.prep_ships()
# Get rid of any remaining bullets and aliens.
self.bullets.empty()
self.aliens.empty()
# Create a new fleet and center the ship.
self._create_fleet()
self.ship.center_ship()
# Pause.
sleep(0.5)
else:
self.game_active = False
pygame.mouse.set_visible(True)
def _update_aliens(self):
"""Check if the fleet is at an edge, then update positions."""
self._check_fleet_edges()
self.aliens.update()
# Look for alien-ship collisions.
if pygame.sprite.spritecollideany(self.ship, self.aliens):
self._ship_hit()
# Look for aliens hitting the bottom of the screen.
self._check_aliens_bottom()
def _check_aliens_bottom(self):
"""Check if any aliens have reached the bottom of the screen."""
for alien in self.aliens.sprites():
if alien.rect.bottom >= self.settings.screen_height:
# Treat this the same as if the ship got hit.
self._ship_hit()
break
def _create_fleet(self):
"""Create the fleet of aliens."""
# Create an alien and keep adding aliens until there's no room left.
# Spacing between aliens is one alien width and one alien height.
alien = Alien(self)
alien_width, alien_height = alien.rect.size
current_x, current_y = alien_width, alien_height
while current_y < (self.settings.screen_height - 3 * alien_height):
while current_x < (self.settings.screen_width - 2 * alien_width):
self._create_alien(current_x, current_y)
current_x += 2 * alien_width
# Finished a row; reset x value, and increment y value.
current_x = alien_width
current_y += 2 * alien_height
def _create_alien(self, x_position, y_position):
"""Create an alien and place it in the fleet."""
new_alien = Alien(self)
new_alien.x = x_position
new_alien.rect.x = x_position
new_alien.rect.y = y_position
self.aliens.add(new_alien)
def _check_fleet_edges(self):
"""Respond appropriately if any aliens have reached an edge."""
for alien in self.aliens.sprites():
if alien.check_edges():
self._change_fleet_direction()
break
def _change_fleet_direction(self):
"""Drop the entire fleet and change the fleet's direction."""
for alien in self.aliens.sprites():
alien.rect.y += self.settings.fleet_drop_speed
self.settings.fleet_direction *= -1
def _update_screen(self):
"""Update images on the screen, and flip to the new screen."""