alien_invasion.py

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 assests and behavior."""
	

	def __init__(self):
		"""Initalizes the game, and create game resources."""
		pygame.init()
		self.settings = Settings()
		
		#self.screen = pygame.display.set_mode((0, 0), pygame.FULLSCREEN)
		#self.settings.screen_width = self.screen.get_rect().width
		#self.settings.screen_height = self.screen.get_rect().height 
		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()

		#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.stats.game_active:
				self.ship.update()
				self._update_bullets()
				self._update_aliens()
			
			self._update_screen()
			
			
	def _check_events(self):
		"""Respond to keypress and mouse events."""
		for event in pygame.event.get():
			if event.type == pygame.QUIT:
				sys.exit()
			elif event.type == pygame.MOUSEBUTTONDOWN:
				mouse_pose = pygame.mouse.get_pos()
				self._check_play_button(mouse_pose)
			elif event.type == pygame.KEYDOWN:
				self._check_keydown_events(event)
			elif event.type == pygame.KEYUP:
				self._check_keyup_events(event)
					
	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 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 disappered
		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 the bullet-alien collisions."""
		#Remove any aliens that have collided
		collisions = pygame.sprite.groupcollide(
		self.bullets, self.aliens, True, True)

		if collisions:
			self.stats.score += self.settings.alien_points
			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()

			#Make the Play button if the game is inactive.
			if not self.stats.game_active:
				self.play_button.draw_button()
	
	def _update_screen(self):
		"""Update images on the screen, and flip to the new screen."""
		self.screen.fill(self.settings.bg_color)
		self.ship.blitme()
		for bullet in self.bullets.sprites():
			bullet.draw_bullets()
		self.aliens.draw(self.screen)

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

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

		pygame.display.flip()
	
	def _create_fleet(self):
		"""Create the fleet of aliens."""
		alien = Alien(self)
		alien_width, alien_height = alien.rect.size
		alien_width = alien.rect.width
		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)
		#Create 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 a row."""
		alien = Alien(self)
		alien_width, alien_height = alien.rect.size
		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
		self.aliens.add(alien)
			
	
	def _update_aliens(self):
		"""Check if the fleet is at the 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()

		#Check for aliens hitting the bottom of the screen
		self._check_aliens_bottom()

	def _ship_hit(self):
		"""Respond to the ship being hit by an alien."""
		if self.stats.ship_left > 0:
			#Decrememnt the ships_left, and update scoreboard
			self.stats.ship_left -= 1
			self.sb.prep_ships()
			#Get rid of any remaing 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_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 _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 way the ship got hit
				self._ship_hit()
				break

	def _check_play_button(self, mouse_pose):
		"""Start a new game when the player clicks play."""
		button_clicked = self.play_button.rect.collidepoint(mouse_pose)
		if button_clicked and not self.stats.game_active:
			#Reset the game settings
			self.settings.initialize_dynamic_settings()
			if self.play_button.rect.collidepoint(mouse_pose):

				#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)

if __name__ == '__main__':
	ai = AlienInvasion()
	ai.run_game()