Alien War

2017-12-30

Project Aim Introduction

I want to lenarn the Python by myself. After I read the << Python Crash course A hands-on ,Project-based Introduction to Programming >>, I want to strengthen my skill by the project.
Click here to visit my Github repository

Project Background Introduction

After I read the << Python Crash course A hands-on , Project-based Introduction to Programming >>, there is a project in the book named Alien War, a 2-dimension game written with python using pygame. A suitable project that will help me to master the language, I think.
So I spend one hour every day to write the source code in the direction of the book, wantting to master the language better and increase the experience in prgramming through the project.

Project Design Introduction

Function Description :

A space ship will stay at the bottom of the screen, only allowed to move rightwards or leftwards which is in the contorl of the payers. A group of aliens will move downwards from the top of the screen, moving rightwards or leftwards. Players are allowed to shot at the aliens. When bullets hit the alien, the alien will be killed and disappear from the screen. After killing all the aliens, there will come another group of aliens. Player will attain the score after every kill and level up while the alens be cleaned every time. If there is an alien hit the space or the bottom of the screen, Players will lose a space ship. Every player has three space ships. Game will over when there is no ship remains. The frequence of the aliens will increase with the level upping and the point of every kill will also increase. Players are requested to get as higher score as they can by their efforts.

Module:

alien_invasion:The entrance of the game, call other modules. Initialize the game and build the initial run environment of the game.
setting:The whole setings of the game, include ship, aliens, bullets, screen, speed, points.
game_function:This module includes many functions run in the game to deal with many events. Such as keyboard down events, update events, create events, hit events, calculate events.
alien:This module is about the description of the alien.
ship:This module is about the dsescripton of the ship.
bullet:This module is about the description of the bullet.
button:This module is about the description of the button, to create a button of starting game.
game_state:To manage the state of the game.
score_board:This module will show the score atthe screen.

Project Implement Introduction

alien_invasion: Import modules: settings, ship, game_states, button, scoreboard. The entrance of the game, there is only one function named as run_game(). Initialize the game and create the screen through pygame. Then create the button, score_board, ship, aliens, bullets, game_states instance. After that, there is a loop can only be ended by the exit() function. Check the keyboard down events, update the alien, ship, bullet and the screen.
source code:

#!/usr/bin/env python
# coding=utf-8
import sys
import pygame
from settings import Settings
from ship import Ship
from pygame.sprite import Group
from game_states import Game_states
from button import Button
from scoreboard import Scoreboard
import game_functions as gamef
def run_game():
    # initialize the game and build 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("Alien War")
    # create a button
    play_button = Button(ai_settings, screen, "Play")
    
    # create a intence of Game_states
    games = Game_states(ai_settings)
    # create the score board
    score_board = Scoreboard(ai_settings, screen, games)
    # set the background
    screen.fill(ai_settings.bg_color)
    # create a ship
    ship = Ship(ai_settings,screen)
    # create a group to store the bullets
    bullets = Group()
    # create a group to store te aliens
    aliens = Group()
    if games.game_active == 1:
        gamef.create_fleet(ai_settings,screen,ship,aliens)
    # start the main loop
    while True:
        # watch the mouse and keyboard
        gamef.check_events(ai_settings,screen,games,score_board,play_button,ship,aliens,bullets)
        if games.game_active == 1:
            # update the locating
            ship.update()
            # update the bullets
            gamef.update_bullet(ai_settings,screen,games,score_board,ship,aliens,bullets)
            # update the aliens
            gamef.update_alien(ai_settings,games,screen,score_board,ship,aliens,bullets)
        # update the screen
        gamef.update_screen(ai_settings,screen,games,score_board,ship,aliens,bullets,play_button) 
run_game()

game_function: Define a largr of functions in the game. The function manu is as follows:

check_keydown_events(event,ai_settings,screen,ship,bullets):
deal with keydown event
check_keyup_events(event,ship):
deal with keyup
check_events(ai_settings,screen,states,score_board,play_button,ship,aliens,bullets):
react to the mouse and keyboard
update_screen(ai_settings,screen,states,score_board,ship,aliens,bullets,play_button):
update the screen
update_bullet(ai_settings,screen,states,score_board,ship,aliens,bullets):
update the bullet and delete the old bullets
update_alien(ai_settings,states,screen,score_board,ship,aliens,bullets):
check the site of the alien and update the site of the every alien
get_number_aliens_x(ai_settings,alien_width):
calculate how many a line a line can contain
get_number_rows(ai_settings,ship_height,alien_height):
calculate how many aliens the screen can contain
create_alien(ai_settings,screen,aliens,alien_number,alien_rows):
create an alien
create_fleet(ai_settings,screen,ship,aliens):
create the group of the aliens
check_fleet_edges(ai_settings,aliens):
what if the aliens hit the edges
change_fleet_direction(ai_settings,aliens):
change the direction of the alien
check_collide_bullet_alien(ai_settings,screen,states,score_board,ship,aliens,bullets):
react to the hit between aliens and bullets
ship_hit(ai_settings,states,screen,score_board,ship,aliens,bullets):
react to the hit between ship and aliens
check_aliens_bottom(ai_settings,states,screen,score_board,ship,aliens,bullets):
check if aliens arrive at the bottom of te screen
check_play_button(ai_settings,screen,states,score_board,play_button,ship,aliens,bullets,mouse_x,mouse_y):
start the ame when click at the button
check_highest_score(states, score_board):
check if there is new score and update the score

setting: Define the variable in the game and initialize the game, include: screen, bullet, alien, ship, speed.
alien: Extends from Sprite, Initialize the alien and define the behavor of the alien: update, check edges.
ship: Extends from Sprte, initialize the ship and define the behavor of the ship: update.
bullet: Extends fom Sprite, initialize the bullet and define the behavor of the bullet: update, draw_rect.
button: Define a button, render the “play” to an image and draw the button.
game_state: Initialize the game’s state, add the reset behavor.
score_board: Initialize the score board, render the score, level, highest score to an image and dislay the elft ship at he score.

Project Summary

I spend one hour every dey almost half the month to write the project in the direction of the book, there are almost the whole source code in the book. I just fix some problems where I think exist some question in the logic. And I also add a start page to beauty the game. Above all, my skill in python has been promoted through the project.