使用pygame的错误，我的精灵不会出现在屏幕上

Question

I'm at the very beginning of a chess program and want to print the board on the screen. However, I am having trouble at the first hurdle and cannot even get it to print the squares of the board. It just comes up with a black screen and doesn't put the sprite on it.

I've tried looking at some code from a previous project where it worked, but I can't find any differences in this part of the program.

import pygame
import os
import time

pygame.init()

WHITE = (0, 30, 0)
BLACK = (200, 200, 200)
screen_width = 1400
screen_height = 800
square_size = screen_height/10
screen = pygame.display.set_mode([screen_width, screen_height])
os.environ['SDL_VIDEO_WINDOWS_POS'] = '10,10'


class square(pygame.sprite.Sprite):
    def __init__(self, colour, x, y):
        super().__init__()
        self.image = pygame.Surface([square_size, square_size])
        pygame.draw.rect(self.image, colour, [0, 0, square_size, square_size])
        self.colour = colour
        self.rect = self.image.get_rect()


squares = pygame.sprite.Group()
s = square(WHITE, 20, 20)
squares.add(s)
squares.draw(screen)
time.sleep(3)

I would expect this to output one white square in the top left hand corner of the screen, but only a black screen appears.

Answer 1

最有可能的问题是，您没有翻转/更新屏幕。

Answer 2

You need an event.get loop, and to update your display using pygame.display.update() after the squares.draw(screen) :

import pygame
import os
import time

pygame.init()

WHITE = (0, 30, 0)
BLACK = (200, 200, 200)
screen_width = 1400
screen_height = 800
square_size = screen_height/10
screen = pygame.display.set_mode([screen_width, screen_height])
os.environ['SDL_VIDEO_WINDOWS_POS'] = '10,10'


class square(pygame.sprite.Sprite):
    def __init__(self, colour, x, y):
        super().__init__()
        self.image = pygame.Surface([square_size, square_size])
        pygame.draw.rect(self.image, colour, [0, 0, square_size, square_size])
        self.colour = colour
        self.rect = self.image.get_rect()

for event in pygame.event.get():
    pass

squares = pygame.sprite.Group()
s = square(WHITE, 20, 20)
squares.add(s)
squares.draw(screen)
pygame.display.update()
time.sleep(3)

Also note, an RGB value of (0, 30, 0) is not white, it's a dark green, if you want bright white try (255, 255, 255) .