alien_invasion.py

import sys
from time import sleep
import pygame
from settings import Settings
from ship import Ship
from bullet import Bullet
from alien import Alien
from star import Star
from game_stats import GameStats
from scoreboard import Scoreboard
from button import Button
from random import randint

class AlienInvasion:
    """Overall class to manage game assets and behavior"""

    def __init__(self):
        """Initialize the game, and create game resources."""
        pygame.init()
        self.settings = Settings()


        self.screen = pygame.display.set_mode(
            (self.settings.screen_width, self.settings.screen_height))
        self.settings.screen_width = self.screen.get_rect().width
        self.settings.screen_height = self.screen.get_rect().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.stars = pygame.sprite.Group()
        self.drops = pygame.sprite.Group()

        self._create_fleet()

        # Make the Play button.
        self.play_button = Button(self, "Play")


    def _ship_hit(self):
        """Respond to the ship being hit by an alien."""
        if self.stats.ships_left > 0:
            # Decrement ships_left.
            self.stats.ships_left -= 1
            self.sb.prep_ships()

            # Get rid of any remaining aliens and bullets.
            self.aliens.empty()
            self.bullets.empty()

            # Create a new fleet and center the ship.
            self._create_fleet()
            self.ship.center_ship()

            # Pause.
            sleep(0.5)
        else:
            self.stats.game_active = False
            pygame.mouse.set_visible(True)


    def _check_bottom(self):
        """Respond appropriaty if any aliens have reached an edge."""
        for drop in self.drops.sprites():
            drop.check_bottom()


    def _create_star_grid(self):
        """Create the grid of stars."""
        # Create an star and find the number of stars in a row.
        # Spacing between each star is equal to one star width.
        star = Star(self)
        star_width, star_height = star.rect.size
        available_space_x = self.settings.screen_width - (2 * star_width)
        number_stars_x = available_space_x // (2 * star_width)

        # Determine the number of rows of stars that fit on the screen.
        ship_height = self.ship.rect.height
        available_space_y = (self.settings.screen_height - (3 * star_height))
        number_rows = available_space_y // (2 * star_height)
        print(available_space_y, number_rows, number_stars_x)

        # Create the full fleet of aliens.
        for row_number in range(number_rows):
            for star_number in range(number_stars_x):
                self._create_star(star_number, row_number)


    def _create_star(self, star_number, row_number):
        # Create an alien and place it in the row.
        star = Star(self)
        star_width, star_height = star.rect.size
        star.x = star_width + 2 * star_width * star_number
        star.rect.x = star.x + randint(-50, 50)
        star.rect.y = star.rect.height + 2 * star.rect.height * row_number
        self.stars.add(star)


    def _create_fleet(self):
        """Create the fleet of aliens."""
        # Create an alien and find the number of aliens in a row.
        # Spacing between each alien is equal to one alien width.
        alien = Alien(self)
        alien_width, alien_height = alien.rect.size
        available_space_x = self.settings.screen_width - (2 * alien_width)
        number_aliens_x = available_space_x // (2 * alien_width)

        # Determine the number of rows of aliens that fit on the screen.
        ship_height = self.ship.rect.height
        available_space_y = (self.settings.screen_height - (3 * alien_height) - ship_height)
        number_rows = available_space_y // (2 * alien_height)
        print(available_space_y, number_rows, number_aliens_x)

        # Create the full fleet of aliens.
        for row_number in range(number_rows):
            for alien_number in range(number_aliens_x):
                self._create_alien(alien_number, row_number)


    def _create_alien(self, alien_number, row_number):
        # Create an alien and place it in the row.
        alien = Alien(self)
        alien_width, alien_height = alien.rect.size
        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
        self.aliens.add(alien)


    def _check_fleet_edges(self):
        """Respond appropriaty 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 run_game(self):
        """Start the main loop for the game."""
        while True:
            self._check_events()

            if self.stats.game_active:
                self.ship.update()
                self._update_bullets()
                self._update_aliens()

            self._update_screen()


    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.stats.game_active:
            # Reset the game settings.
            self.settings.initialize_dynamic_settings()
            # Reset the game statistics.
            self.stats.reset_stats()
            self.stats.game_active = True
            self.sb.prep_score()
            self.sb.prep_level()
            self.sb.prep_ships()

            # Get rid of any remaining aliens and bullets.
            self.aliens.empty()
            self.bullets.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_aliens_bottom(self):
        """Check if any aliens have reached the bottom of the screen."""
        screen_rect = self.screen.get_rect()
        for alien in self.aliens.sprites():
            if alien.rect.bottom >= screen_rect.bottom:
                # Treat this the same as if the ship got hit.
                self._ship_hit()
                break


    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()

        # Check for any bullets that have hit aliens.
        # If so, get rid of the bullet and the alien.
        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()


    def _check_bullet_alien_collisions(self):
        """Response to bullet-alien collisions."""
        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 _update_aliens(self):
        """
        Check if the fleet is at an edge,
        then update the positions of all aliens in the fleet
        """
        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 _update_screen(self):
        """Update images on the screen, and flip to the new screen."""
        # Redraw the screen during each pass through the loop.
        self.screen.fill(self.settings.bg_color)
        self.ship.blitme()
        for bullet in self.bullets.sprites():
            bullet.draw_bullet()
        self.aliens.draw(self.screen)
        self.drops.draw(self.screen)

        # Draw the score information
        self.sb.show_score()

        # Draw the play button if the game is inactive
        if not self.stats.game_active:
            self.play_button.draw_button()

        # Make the most recently drawn screen visible.
        pygame.display.flip()


    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_UP:
        #    self.ship.moving_up = True
        #elif event.key == pygame.K_DOWN:
        #    self.ship.moving_down = True
        elif event.key == pygame.K_q:
            sys.exit()
        elif event.key == pygame.K_SPACE:
            self._fire_bullet()


    def _check_keyup_events(self, event):
        """Response 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
        #elif event.key == pygame.K_UP:
        #    self.ship.moving_up = False
        #elif event.key == pygame.K_DOWN:
        #    self.ship.moving_down = 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)


if __name__ == '__main__':
    # Make a game instance, and run the game.
    ai = AlienInvasion()
    ai.run_game()