Pygame精灵太慢了

我最近在Pygame从事游戏。它会加载两个不同的背景（以供将来进行视差滚动），然后将其放置在可以用箭头键控制并且可以左右移动的精灵中。在我运行它之前，所有负载都可以正常运行，直到尝试控制精灵为止。它的响应速度很慢，我必须继续按箭头键才能使其移动。我用来移动精灵的代码与我之前在另一个程序中使用的代码相同，该程序只是在后台和精灵中加载并控制了精灵的移动。对于我的新程序，我刚刚添加了屏幕调整大小和全屏选项。那是当它变慢的时候。是什么在减慢速度？我需要更好地优化代码吗？

如果这样做有帮助，我还注意到当我快速按下另一个键以及箭头键时，它会以正确的速度移动。就像这样更新它。是否需要进行某种更新？另外，我已经在if语句中使用了“ Pygame.display.update（）”来进行精灵键控制。

import pygame
from pygame.locals import *

pygame.init()

#two backgrounds
bg = pygame.image.load('/Users/luke.redwine/Documents/Python/PyGame/Llama game/Llama imaging/backgrounds concepts/Mountains/PPP_BG1.png')
fg = pygame.image.load('/Users/luke.redwine/Documents/Python/PyGame/Llama game/Llama imaging/backgrounds concepts/Mountains/PPP_fg1.png')

clock = pygame.time.Clock()

def Sresize():
    #screen resize:
    pygame.event.pump()                                                                 

    event=pygame.event.wait()                                                            

    if event.type==QUIT:
        pygame.quit()                                              

    elif event.type==VIDEORESIZE:                                                           
        sprite.screen=pygame.display.set_mode(event.dict['size'],HWSURFACE|DOUBLEBUF|RESIZABLE)
        sprite.screen.blit(pygame.transform.scale(bg,event.dict['size']),(0,0))
        sprite.screen.blit(pygame.transform.scale(fg,event.dict['size']),(0,0))
        pygame.display.update()


#PLAYER CLASS

class player(object):
    def __init__(self,x, y, width, height):     
        self.x = x                                   
        self.y = y                          
        self.width = width                            
        self.height = height                          
        self.velocity = 15
        self.isJump = False
        self.jumpCount = 7
        self.right = False
        self.left = False
        self.walkCount = 0
        self.screen = pygame.display.set_mode((1280, 800), HWSURFACE|DOUBLEBUF|RESIZABLE)
        self.walkRight = [pygame.image.load('/Users/luke.redwine/Documents/Python/PyGame/Examples/sprite-Game/sprite characters main/R %s.png' % frame) for frame in range(1, 9)]
        self.walkLeft = [pygame.image.load('/Users/luke.redwine/Documents/Python/PyGame/Examples/sprite-Game/sprite characters main/L %s.png' % frame) for frame in range(14, 21)]
        self.char = pygame.image.load('/Users/luke.redwine/Documents/Python/PyGame/Examples/sprite-Game/sprite characters main/character 25.png')


    def draw(self, screen):                         

        if self.walkCount + 1 >= 8:  
            self.walkCount = 0      

        if self.left:
            self.screen.blit(self.walkLeft[self.walkCount//1], (self.x, self.y))
            self.walkCount += 1

        elif self.right:
            self.screen.blit(self.walkRight[self.walkCount//1], (self.x, self.y))
            self.walkCount += 1

        else:
            self.screen.blit(self.char, (self.x, self.y))



sprite = player(4, 480, 16, 16)

def redrawGamescreen():                      

    sprite.screen.blit(pygame.transform.scale(bg,(1280, 800)),(0,0))   
    sprite.screen.blit(pygame.transform.scale(fg,(1280, 800)),(0,0))   
    sprite.draw(sprite.screen)
    pygame.display.update()



#mainloop:-----------------------------------------------------------------
run = True

while run:
    keys = pygame.key.get_pressed()
    Sresize()
    clock.tick(20)
#left

    if keys[pygame.K_LEFT] and sprite.x > sprite.velocity:
        sprite.x -= sprite.velocity
        sprite.left = True
        sprite.right = False

#right 

    elif keys[pygame.K_RIGHT] and sprite.x < 1280 - sprite.width - sprite.velocity:
        sprite.x += sprite.velocity
        sprite.right = True
        sprite.left = False

#otherwise, stand still

    else:
        sprite.right = False
        sprite.left = False
        sprite.walkCount = 0

#jumping


    if not(sprite.isJump):

        if keys[pygame.K_SPACE]:
            sprite.isJump = True
            sprite.right = False
            sprite.left = False

    else:
        if sprite.jumpCount >= -7:
            neg = 1        
            pygame.display.update()
            if sprite.jumpCount < 0:
                neg = -1

            sprite.y -= (sprite.jumpCount ** 2) * 0.5 * neg 
            sprite.jumpCount -= 1

        else:
            sprite.isJump = False
            sprite.jumpCount = 7 
            sprite.velocity = 15

    redrawGamescreen()

pygame.quit()