为什么我的 Pygame 精灵在我 blit 到屏幕时不移动？

Question

I tried to blit a sprite to the screen in Pygame.

Here's my code:

import pygame
from pygame.locals import (
    K_UP,
    K_DOWN,
    K_LEFT,
    K_RIGHT,
    K_ESCAPE,
    KEYDOWN,
    QUIT
)
WINDOW = pygame.display.set_mode((800,800))

class Player(pygame.sprite.Sprite):
    def __init__(self):
        self.x = 0
        self.y = 0
        super().__init__()
        self.surf = pygame.Surface((50,50))
        self.surf.fill((20, 115, 224))
        self.rect = self.surf.get_rect()
    def update(self):
        print("Updated")
        GRAVITY = 10
        self.y += GRAVITY
        self.rect = (self.x,self.y)


def game_loop():
    run = True



    while run:
        WINDOW.fill((52, 183, 235))
        Player().update()
        WINDOW.blit(Player().surf,(Player().x,Player().y))
        pygame.display.update()
        for event in pygame.event.get():
            if event.type == QUIT:
                run = False
                pygame.quit()



if __name__ == "__main__":
    game_loop()

The specific part I am having trouble with are:

def update(self):
    print("Updated")
    GRAVITY = 10
    self.y += GRAVITY
    self.rect = (self.x,self.y)

and

    Player().update()
    WINDOW.blit(Player().surf,(Player().x,Player().y))

When I run this code, the sprite doesn't move from the screen even though self.y is being added by gravity. How can I fix it?

Answer 1

As I understand your code, you are instantiating a new Player() with default settings everytime you refer to Player() .

Try:

import pygame
from pygame.locals import (
    K_UP,
    K_DOWN,
    K_LEFT,
    K_RIGHT,
    K_ESCAPE,
    KEYDOWN,
    QUIT
)

WINDOW = pygame.display.set_mode((800,800))


class Player(pygame.sprite.Sprite):
    def __init__(self):
        self.x = 0
        self.y = 0
        super().__init__()
        self.surf = pygame.Surface((50, 50))
        self.surf.fill((20, 115, 224))
        self.rect = self.surf.get_rect()

    def update(self):
        print("Updated")
        GRAVITY = 10
        self.y += GRAVITY
        self.rect = (self.x, self.y)


def game_loop():
    run = True

    player = Player()    
    while run:
        WINDOW.fill((52, 183, 235))
        player.update()
        WINDOW.blit(player.surf, (player.x, player.y))
        pygame.display.update()
        for event in pygame.event.get():
            if event.type == QUIT:
                run = False
                pygame.quit()


if __name__ == "__main__":
    game_loop()