First of all, I'm sorry , I haven't updated it for too long . Mid Autumn Festival went out to play, there is no update , Then another week of new employee training , therefore , I didn't have time to update , I went home to accompany my parents during the National Day , Today is a day off , Seize the time to update . If there are no special circumstances , Try to use the weekend time to update articles for everyone . therefore , For the recent delay, let's say sorry again ！ The previous two articles introduced the creation of aliens , This includes The creation of the first alien as well as The creation of a group of aliens . In fact, it is not difficult for us to find and compare with the front in creating the implementation of Alien Creation Creation of spacecraft The principle is the same , It's just that some small details are different . This article introduces the alien group we created to move ！
Next, let's move the alien crowd to the right on the screen , Hit the edge of the screen and move down a certain distance , Then move in the opposite direction . We will continue to move all aliens , Until all aliens are eliminated , An alien hit a spaceship , Or aliens arrive at the bottom of the screen . Next , We first realize that aliens move to the right .
For mobile aliens , We will use alien.py The method in update(), And call it for every alien in the alien population . First , We are settings.py Add a setting to control alien speed at the end ：
class Settings(): """ Storage 《 Alien invasion 》 All settings classes for """ def __init__(self): """ Initialize game settings """ # Screen settings self.screen_width = 1400 self.screen_height = 700 self.bg_color = (230, 230, 230) # Spacecraft setup self.ship_speed_factor = 1.5 # Bullet settings self.bullet_speed_factor = 3.6 self.bullet_width = 3 self.bullet_height = 15 self.bullet_color = 60, 60, 60 self.bullets_allowed = 6 # Alien settings self.alien_speed_factor = 1
then , We are alien.py Setting implementation in update()：
import pygame
from pygame.sprite import Sprite
class Alien(Sprite):
""" Class representing a single alien """
def __init__(self, ai_settings, screen):
""" Initialize the alien and set its starting position """
super(Alien, self).__init__()
self.screen = screen
self.ai_settings = ai_settings
# Loading alien images , And set its rect attribute
self.image = pygame.image.load("images/alien.bmp")
self.rect = self.image.get_rect()
# Each alien was initially near the top left corner of the screen
self.rect.x = self.rect.width
self.rect.y = self.rect.height
# Store the exact location of Aliens
self.x = float(self.rect.x)
def blitme(self):
""" Draw aliens in designated locations """
self.screen.blit(self.image, self.rect)
def update(self):
""" Moving aliens to the right """
self.x += self.ai_settings.alien_speed_factor
self.rect.x = self.x
Every time you update the alien's location , Move it to the right , The amount of movement is alien_speed_factor Value , We use properties self.x Track the exact location of each Alien , This property can store small values . then , We use self.x To update the alien's rect Location . In the main while The method to update the ship and bullets has been called in the loop , But now we need to alien_invasion.py Update the location of each Alien ：
import sys
import pygame
from settings import Settings
from ship import Ship
import game_functions as gf
from pygame.sprite import Group
from alien import Alien
def run_game():
# Initialize the game and create a screen object
pygame.init()
ai_settings = Settings()
screen = pygame.display.set_mode((ai_settings.screen_width, ai_settings.screen_height))
pygame.display.set_caption("Alian Invasion")
# Create a spaceship 、 A bullet train and an alien train
ship = Ship(ai_settings, screen)
# Create a group for storing bullets
bullets = Group()
aliens = Group()
# Creating alien groups
# alien = Alien(ai_settings, screen)
gf.create_fleet(ai_settings, screen, ship, aliens)
# Start the main cycle of the game
while True:
# Monitor keyboard and mouse events
gf.check_events(ai_settings, screen, ship, bullets)
ship.update()
gf.update_bullets(bullets)
gf.update_aliens(aliens)
gf.update_screen(ai_settings, screen, ship, aliens, bullets)
run_game()
We'll update the location of the aliens after updating the bullets , Because we'll check later to see if any bullets hit aliens . Finally, in the document game_funcation.py Add function at the end update_aliens():
import sys import pygame from bullet import Bullet from alien import Alien def check_keydown_events(event, ai_settings, screen, ship, bullets): """ Response button """ 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: # Create a bullet , And add it to the group bullets in fire_bullet(ai_settings, screen, ship, bullets) elif event.key == pygame.K_q: sys.exit() def fire_bullet(ai_settings, screen, ship, bullets): """ If the limit has not been reached , Just fire a bullet """ if len(bullets) < ai_settings.bullets_allowed: new_bullet = Bullet(ai_settings, screen, ship) bullets.add(new_bullet) def check_keyup_events(event, ship): """ Response loosening """ 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, ship, bullets): """ Respond to key 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, ship) def update_screen(ai_settings, screen, ship, aliens, bullets): """ Update image on screen , And switch to the new screen """ # Redraw the screen every time you cycle screen.fill(ai_settings.bg_color) # Redraw all the bullets behind the spaceship and the alien for bullet in bullets.sprites(): bullet.draw_bullet() ship.blitme() aliens.draw(screen) # Make the most recently drawn screen visible pygame.display.flip() def update_bullets(bullets): """ Update bullet position , And delete the missing bullets """ # Update bullet position bullets.update() # Delete bullets that have disappeared for bullet in bullets.copy(): if bullet.rect.bottom <= 0: bullets.remove(bullet) def get_number_aliens_x(ai_settings, alien_width): avaliable_space_x = ai_settings.screen_width - 2 * alien_width number_aliens_x = int(avaliable_space_x / (2 * alien_width)) return number_aliens_x def create_alien(ai_settings, screen, aliens, alien_number, row_number): # Create an alien , And calculate how many aliens a row can hold 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): """ Creating alien groups """ 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 first line of Aliens for row_number in range(number_rows): for alien_number in range(number_aliens_x): # Create an alien and add it to the current line create_alien(ai_settings, screen, aliens, alien_number, row_number) def get_number_rows(ai_settings, ship_height, alien_height): """ How many lines of aliens can the screen hold """ 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 update_aliens(aliens): """ Update the location of all aliens in the alien crowd """ aliens.update()
We're right aliens Calling method update(), This will automatically call the method... For each alien update(). If we run this game now , You'll see the aliens moving to the right , And gradually disappear on the right edge of the screen , The specific effect is as follows ：
Now let's create an alien to hit the right edge of the screen and move down 、 Move the setting to the left again , We started with settings.py Make the following settings in ：
class Settings(): """ Storage 《 Alien invasion 》 All settings classes for """ def __init__(self): """ Initialize game settings """ # Screen settings self.screen_width = 1400 self.screen_height = 700 self.bg_color = (230, 230, 230) # Spacecraft setup self.ship_speed_factor = 1.5 # Bullet settings self.bullet_speed_factor = 3.6 self.bullet_width = 3 self.bullet_height = 15 self.bullet_color = 60, 60, 60 self.bullets_allowed = 6 # Alien settings self.alien_speed_factor = 1 self.fleet_drop_speed = 10 # fleet_direction by 1 To the right , by -1 Move left self.fleet_direction = 1
Set up fleet_drop_speed Specifies when an alien hits the edge of the screen , The speed at which the aliens move down . It's good to separate this speed from horizontal speed , So we can adjust the two speeds separately . To achieve fleet_direction Set up , You can set it to a text value , Such as left or right, But then you have to write if-elif Statement to check the moving direction of the alien crowd . Since only these two directions are possible , We use value 1 and -1 To represent them , And switch between these two values when the alien crowd changes direction . in addition , In view of the need to increase the size of each alien when moving to the right x coordinate , Moving to the left requires reducing each Alien x Coordinates of , It's more reasonable to use numbers to indicate direction .
Now you need to write a method to check whether aliens hit the edge of the screen , Need modification alien.py Medium update(), So that every alien moves in the right direction ：
import pygame
from pygame.sprite import Sprite
class Alien(Sprite):
""" Class representing a single alien """
def __init__(self, ai_settings, screen):
""" Initialize the alien and set its starting position """
super(Alien, self).__init__()
self.screen = screen
self.ai_settings = ai_settings
# Loading alien images , And set its rect attribute
self.image = pygame.image.load("images/alien.bmp")
self.rect = self.image.get_rect()
# Each alien was initially near the top left corner of the screen
self.rect.x = self.rect.width
self.rect.y = self.rect.height
# Store the exact location of Aliens
self.x = float(self.rect.x)
def blitme(self):
""" Draw aliens in designated locations """
self.screen.blit(self.image, self.rect)
def check_edges(self):
""" If aliens are on the edge of the screen , Just go back to True"""
screen_rect = self.screen.get_rect()
if self.rect.right >= screen_rect.right:
return True
elif self.rect.left <= 0:
return True
def update(self):
""" Move aliens left or right """
self.x += (self.ai_settings.alien_speed_factor * self.ai_settings.fleet_direction)
self.rect.x = self.x
We can call new methods on any alien check_edges(), See if it's on the left or right edge of the screen . If alien rect Of right Property greater than or equal to the screen's rect Of right attribute , That means aliens are on the right edge of the screen . If alien rect Of left Property less than or equal to 0, That means aliens are on the left edge of the screen . We modified the method update(), Set the amount of movement to alien speed and fleet_direction The product of the , Let aliens move left or right . If fleet _direction by 1, The alien's current x The coordinates increase to alien_speed_factor, To move the aliens to the right ; If fleet_direction by -1, The alien's current x Coordinate subtraction alien_speed_factor, To move the aliens to the left .
When an alien reaches the edge of the screen , We need to move the whole group of aliens down , And change the direction they move . We need to be right about game_function.py Make major changes , because , We're going to check here whether aliens have reached the left edge or the right edge . So , We write functions check_fleet_edges() and change_fleet_direction(), Also on update_aliens() It's been modified ：
import sys import pygame from bullet import Bullet from alien import Alien def check_keydown_events(event, ai_settings, screen, ship, bullets): """ Response button """ 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: # Create a bullet , And add it to the group bullets in fire_bullet(ai_settings, screen, ship, bullets) elif event.key == pygame.K_q: sys.exit() def fire_bullet(ai_settings, screen, ship, bullets): """ If the limit has not been reached , Just fire a bullet """ if len(bullets) < ai_settings.bullets_allowed: new_bullet = Bullet(ai_settings, screen, ship) bullets.add(new_bullet) def check_keyup_events(event, ship): """ Response loosening """ 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, ship, bullets): """ Respond to key 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, ship) def update_screen(ai_settings, screen, ship, aliens, bullets): """ Update image on screen , And switch to the new screen """ # Redraw the screen every time you cycle screen.fill(ai_settings.bg_color) # Redraw all the bullets behind the spaceship and the alien for bullet in bullets.sprites(): bullet.draw_bullet() ship.blitme() aliens.draw(screen) # Make the most recently drawn screen visible pygame.display.flip() def update_bullets(bullets): """ Update bullet position , And delete the missing bullets """ # Update bullet position bullets.update() # Delete bullets that have disappeared for bullet in bullets.copy(): if bullet.rect.bottom <= 0: bullets.remove(bullet) def get_number_aliens_x(ai_settings, alien_width): avaliable_space_x = ai_settings.screen_width - 2 * alien_width number_aliens_x = int(avaliable_space_x / (2 * alien_width)) return number_aliens_x def create_alien(ai_settings, screen, aliens, alien_number, row_number): # Create an alien , And calculate how many aliens a row can hold 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): """ Creating alien groups """ 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 first line of Aliens for row_number in range(number_rows): for alien_number in range(number_aliens_x): # Create an alien and add it to the current line create_alien(ai_settings, screen, aliens, alien_number, row_number) def get_number_rows(ai_settings, ship_height, alien_height): """ How many lines of aliens can the screen hold """ 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 check_fleet_edges(ai_settings, aliens): """ When aliens reach the edge, take corresponding measures """ for alien in aliens.sprites(): if alien.check_edges(): change_fleet_direction(ai_settings, aliens) break def change_fleet_direction(ai_settings, aliens): """ Move the whole group of aliens down , And change their direction """ for alien in aliens.sprites(): alien.rect.y += ai_settings.fleet_drop_speed ai_settings.fleet_direction = -1 def update_aliens(ai_settings, aliens): """ Check for aliens on the edge of the screen , And update the location of the entire group of aliens """ check_fleet_edges(ai_settings, aliens) aliens.update()
stay check_fleet_edges() in , We traverse the Alien Swarm , And call... For each of them check_edges(). If check_edges() return True, We know that the corresponding alien is at the edge of the screen , We need to change the direction of the alien population , therefore , We call change_fleet_direction() And exit the loop . stay change_fleet_direction() in , We traverse all aliens , Move each alien down fleet_drop_speed Set the value of the ; then , take fleet_direction The value of is changed to its current value and -1 The product of the . We modified the function update_aliens(), In which you call check_fleet_edges() To determine if there are aliens at the edge of the screen . Now? , function update_aliens() Contains formal parameters ai_settings, therefore , When we call it, we specify the and ai_settings The corresponding argument ：
import sys
import pygame
from settings import Settings
from ship import Ship
import game_functions as gf
from pygame.sprite import Group
from alien import Alien
def run_game():
# Initialize the game and create a screen object
pygame.init()
ai_settings = Settings()
screen = pygame.display.set_mode((ai_settings.screen_width, ai_settings.screen_height))
pygame.display.set_caption("Alian Invasion")
# Create a spaceship 、 A bullet train and an alien train
ship = Ship(ai_settings, screen)
# Create a group for storing bullets
bullets = Group()
aliens = Group()
# Creating alien groups
# alien = Alien(ai_settings, screen)
gf.create_fleet(ai_settings, screen, ship, aliens)
# Start the main cycle of the game
while True:
# Monitor keyboard and mouse events
gf.check_events(ai_settings, screen, ship, bullets)
ship.update()
gf.update_bullets(bullets)
gf.update_aliens(ai_settings, aliens)
gf.update_screen(ai_settings, screen, ship, aliens, bullets)
run_game()
If we run this game now , The Alien Swarm will move back and forth on the screen , And move down after reaching the edge of the screen , The specific effect is as follows ：
The previous two articles introduced the creation of aliens , This includes The creation of the first alien as well as The creation of a group of aliens . In fact, it is not difficult for us to find and compare with the front in creating the implementation of Alien Creation Creation of spacecraft The principle is the same , It's just that some small details are different . This paper introduces how to make our alien group move , We first let the aliens move to the right , Then set the alien's moving direction and check whether the alien can hit the edge of the screen and further operate ： I.e. move down . Next , We can introduce the realization of the alien elimination function . In order to let everyone better absorb the knowledge points used in the project , Each of our articles is only for you to realize 《 Alien invasion 》 A function of , therefore , I hope you can read it carefully , Write the code carefully , Understand the deep meaning , Let's maximize the value of this project . In fact, this project is already very typical , The code is everywhere , however , If you just paste and copy , There is no value in learning your knowledge , You still have to follow , Then you should know the meaning of each line of code or which knowledge point we introduced earlier , That's the only way , This project will play a different value , I hope you will study hard , Lay a solid foundation of basic knowledge .Python It's a practical language , It is the simplest of many programming languages , It's also the best way to get started . When you learn the language , Go to study again java、go as well as C The language is relatively simple . Of course ,Python It's also a popular language , It is very helpful for the realization of artificial intelligence , therefore , It's worth your time to learn . Life is endless , Struggle is more than , We work hard every day , study hard , Constantly improve your ability , I believe I will learn something . come on. ！！！
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