Character gets stuck / freezes in pygame

Question

I'm trying to make a racing game with pygame (not finished) by following a tutorial on youtube. The code works totally fine, except when I pressed the arrowkey and pressed the opposite of that arrowkey really quickly, the race car gets stuck until I let the key go and press the key again. Is there any way to fix that?

import pygame

pygame.init()

display_width = 800
display_height = 600

black = (0, 0, 0)
white = (255, 255, 255)
red = (255, 0, 0)

gameDisplay = pygame.display.set_mode((display_width, display_height))
pygame.display.set_caption('A bit Racey')
clock = pygame.time.Clock()


carImg = pygame.image.load('BlackCar.png')

def car(x, y):
    gameDisplay.blit(carImg, (x, y))

x = (display_width * 0.45)
y = (display_height * 0.8)

x_change = 0
y_change = 0

crashed = False

while not crashed:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            crashed = True

        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                x_change = -5
            if event.key == pygame.K_RIGHT:
                x_change = 5
            if event.key == pygame.K_UP:
                y_change = -5
            if event.key == pygame.K_DOWN:
                y_change = 5

        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                x_change = 0
            if event.key == pygame.K_UP or event.key == pygame.K_DOWN:
                y_change = 0

    x += x_change
    y += y_change


    gameDisplay.fill(white)
    car(x, y)
    pygame.display.flip()
    clock.tick(60)

pygame.quit()
quit()

Alright, try to remove the code for KEYUP event, see what happens and let me know. Let's delete above comments for brevity. — LazyCoder
you may use x_change -= 5 x_change += 5 in KEYDOWN and KEYUP and then it should work better. It will "cumulate both arrows and it will "remeber" previous arrow when you release other arrow. Now when you release second key then it set x_change = 0 and it doen't remeber second key. — furas

furas furas · Accepted Answer · 2019-07-28T11:48:47

You can use x_change -= 5 and x_change += 5 in KEYDOWN and KEYUP

When you keep left arrow then it move left, when you press also right arrow (both are pressed) then it doesn't move but if you release one of arrow and still keep other then it move again (in correct direction)

while not crashed:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            crashed = True

        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                x_change -= 5
            if event.key == pygame.K_RIGHT:
                x_change += 5
            if event.key == pygame.K_UP:
                y_change -= 5
            if event.key == pygame.K_DOWN:
                y_change += 5

        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT:
                x_change += 5
            if event.key == pygame.K_RIGHT:
                x_change -= 5
            if event.key == pygame.K_UP:
                y_change += 5
            if event.key == pygame.K_DOWN:
                y_change -= 5

Character gets stuck / freezes in pygame

1 Answers