How Do I Fix My Ball Animation In Pygame?

Question

So my ball animation for my multiplayer pong game is broken. Instead of moving and bouncing normally, the ball draws it self again after moving.

How do i fix the ball to not like clone itself after it moves 5 pixels? This is the animation code:

enter code here
import pygame

pygame.init()

#Creating the window
screen_width, screen_height = 1000, 600
screen = pygame.display.set_mode((screen_width, screen_height))
pygame.display.set_caption("Pong")

#FPS
FPS = 60
clock = pygame.time.Clock()

#Game Variables
light_grey = (170,170,170)

#Paddles
paddle_1 = pygame.Rect(screen_width - 30, screen_height/2 - 70, 20,100)
paddle_2 = pygame.Rect(10, screen_height/2 - 70, 20, 100)

#Ball
ball = pygame.Rect(screen_width/2, screen_height/2, 30, 30)
ball_xVel = 5
ball_yVel = 5

def ball_animation():
    global ball_xVel, ball_yVel
    ball.x += ball_xVel
    ball.y += ball_yVel

    if ball.x > screen_width or ball.x < 0:
        ball_xVel *= -1
    if ball.y > screen_height or ball.y < 0:
        ball_yVel *= -1

def draw():
        pygame.draw.ellipse(screen, light_grey,  ball)
        pygame.draw.rect(screen, light_grey, paddle_1)
        pygame.draw.rect(screen, light_grey, paddle_2)


def main():

    #main game loop
    run = True
    while run:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                run = False
    
        draw()
        ball_animation()


        pygame.display.update()
        clock.tick(FPS)

    pygame.quit()


if __name__ == "__main__":
    main()

score 0 · Accepted Answer · answered May 22 '21 at 06:30

You have to clear the display in every frame with pygame.Surface.fill:

screen.fill(0)

The typical PyGame application loop has to:

handle the events by either pygame.event.pump() or pygame.event.get().
update the game states and positions of objects dependent on the input events and time (respectively frames)
clear the entire display or draw the background
draw the entire scene (blit all the objects)
update the display by either pygame.display.update() or pygame.display.flip()
limit frames per second to limit CPU usage with pygame.time.Clock.tick

def main():

    # main application loop
    run = True
    while run:
        
        # event loop
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                run = False

        # update and move objects
        ball_animation()

        # clear the display
        screen.fill(0)

        # draw the scene   
        draw()

        # update the display
        pygame.display.update()

        # limit frames per second
        clock.tick(FPS)

pygame.quit()
exit()

How Do I Fix My Ball Animation In Pygame?

1 Answers1