PYGAME about the automatic movement of the rectangle (bounce on the boundary)

import pygame, sys
from settings1 import plant_game

ai_setting = plant_game()


class moving():
    def __init__(self, ai_setting, screen):
        self.screen = ai_setting.screen
        self.ai_setting = ai_setting
        self.image = pygame.Surface((60, 40))
        self.rect = self.image.get_rect()
        self.get_rect = screen.get_rect()
        self.rect.centerx = self.get_rect.centerx
        self.rect.bottom = (self.get_rect.bottom) / 2
        print(self.rect.centerx)

    def blite(self):
        ai_setting.screen.blit(self.image, self.rect)

    def update(self):
        self.rect.centerx += ai_setting.ship_speed_factor
        if self.rect.centerx > 800 or self.rect.centerx < 0:
            ai_setting.ship_speed_factor = -ai_setting.ship_speed_factor




def run():
    ship = moving(ai_setting, ai_setting.screen)
    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                sys.exit()

        ai_setting.screen.fill((255, 255, 255))
        ship.blite()
        ship.update()
        pygame.display.update()
        pygame.display.flip()


run()

Yesterday I finally made it. If you don’t use the class method, you can easily make the code for the rectangle to automatically collide left and right. I mainly call two functions.

• One is to draw the rectangle function blite function: draw a Surface on the screen (on the screen)
• The second is to update the rectangular position function: update, this formula is also a long time I have thought about these two days, forgive me for not being a science student. .

I first put the square RECT in the middle of the screen, I let it self.rect.centerx = self.screen.get_rect.centerx (the meaning of this equation is that I set the X coordinate of its rect in the middle of the screen, which is the screen's Middle), self.rect.bottom = (self.screen.get_rect.bottom)/2 (meaning, I set the Y-axis coordinate of its RECT in the middle of the width of the screen), so there is such a picture

interface The rectangle moves down.

 def update(self):
       self.rect.centerx += ai_setting.ship_speed_factor
       if self.rect.centerx > 800 or self.rect.centerx < 0:
           ai_setting.ship_speed_factor = -ai_setting.ship_speed_factor
          

This formula means that I first move the X-axis of the square. If the center of the square (centerx)>the length of the screen is 800 or less than the length of the screen, then the moving speed becomes negative.
I didn't understand this formula at first, but it suddenly dawned on me later. . The first movement is a positive movement, the second is a negative movement, and the third is a negative movement. This keeps looping, and you can always move in the area I gave.

The following are the parameters of the module:

import pygame
class plant_game():
    def __init__(self):
        pygame.init()
        self.screen = pygame.display.set_mode((800,600))
        self.bg_color = (230,230,230)
        self.ship_speed_factor = 1
        self.bullet_speed_factor = 0.5
        self.bullet_width = 10
        self.bullet_height = 15
        self.bullet_color = 60,60,60
        self.bullet_allow = 3
        self.screen_width = self.screen.get_width()
        self.screen_height = self.screen.get_height()
        self.alien_speed_factor = 1
        self.fleet_drop = 10
        self.fleet_direction = 1

For this parameter module, I use the setting parameters in the aircraft war, which does not affect my creation of moving rectangles.