PyGame aircraft war game background implementation

Aircraft war game background

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One . Thought analysis

1. The goal is

• The idea of background alternating rolling is determined

• Show game background

  1. The idea of background alternating rolling is determined
  function Lesson preparation code , Observe Display effect of background image ：

  • After the game starts , background image Meeting Continuously Down Move
  • stay Visually The plane that produces heroes keeps flying upward illusion —— The routine commonly used in many Parkour games
    • The background of the game Constantly changing
    • The protagonist of the game The position remains the same

2. Analysis of implementation ideas

1. Create two background images
   • The first 1 Zhang Completely coincident with the screen
   • The first 2 Zhang Zai Right above the screen
2. Two images Move downward together
   • self.rect.y += self.speed
3. When Any background sprite Of rect.y >= The height of the screen That has been Move to the bottom of the screen
4. take Move to the image at the bottom of the screen Set to Right above the screen
   • rect.y = -rect.height

3. Design background class

• Initialization method
  • Direct designation Background image
  • is_alt Determine whether it is another image
    • False Express The first image , Need to coincide with the screen
    • True Express Another image , Right above the screen
• update() Method
  • Judge Whether to move out of the screen , If it is , Set the image to Right above the screen , So as to achieve Alternate scrolling

Inherit If the method provided by the parent class , Can't meet the needs of subclasses ：

• Derive a subclass
• For specific requirements in subclasses , Override parent method , And expand

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Two . Show game background

1 . The basic implementation of background wizard

• stay plane_sprites newly build Background Inherited from GameSprite

class Background(GameSprite):
    """ Game background wizard """

    def update(self):

        # 1.  Call the method implementation of the parent class 
        super().update()

        # 2.  Determine whether to move out of the screen , If you move out of the screen , Set the image to the top of the screen 
        if self.rect.y >= SCREEN_RECT.height:
            self.rect.y = -self.rect.height

2 . stay plane_main.py Show background sprites in

1. stay __create_sprites Create in method spirit and Spirit group
2. stay __update_sprites In the method , Give Way Spirit group call update() and draw() Method

__create_sprites Method

def __create_sprites(self):

    #  Create background sprites and Sprite groups 
    bg1 = Background("./images/background.png")
    bg2 = Background("./images/background.png")
    bg2.rect.y = -bg2.rect.height
    
    self.back_group = pygame.sprite.Group(bg1, bg2)

__update_sprites Method

def __update_sprites(self):

    self.back_group.update()
    self.back_group.draw(self.screen)

3、 ... and . Use the initialization method , Simplify the creation of background sprites

reflection —— What kind of problems exist in the code completed in the previous summary ？ Can it be simplified ？

• In the main program , Create two background sprites , Passed in the same image file path
• establish the second Background Genie when , In the main program , Set the image position of the background sprite

reflection —— spirit initial position Set up , should The main program is responsible for ？ still The elves themselves are responsible for ？

answer —— The elves themselves are responsible for

• According to the principle of object-oriented design , The responsibility of the object should be , Encapsulated inside the code of the class

• Try to simplify the code call of the program caller

• Initialization method

  • Direct designation Background image
  • is_alt Determine whether it is another image
    • False Express The first image , Need to coincide with the screen
    • True Express Another image , Right above the screen

stay plane_sprites.py To realize Background Of Initialization method

def __init__(self, is_alt=False):

    image_name = "./images/background.png"
    super().__init__(image_name)
       
    #  Determine whether to alternate pictures , If it is , Set the picture to the top of the screen 
    if is_alt:
        self.rect.y = -self.rect.height     

modify plane_main Of __create_sprites Method

#  Create background sprites and Sprite groups 
bg1 = Background()
bg2 = Background(True)

self.back_group = pygame.sprite.Group(bg1, bg2)

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Four . Summary

This chapter outlines the construction of the background of the aircraft war game , Use object-oriented thinking to realize , Generally speaking, it's not difficult , Just some grammar to remember , It will be reused later .

Where are the deficiencies or better suggestions , Welcome to make complaints about Tucao , If you don't understand anything, you can confide in me , I will reply one by one. , Thank you for your approval , Thank you for your support ！