How to fix flickering of objects and figures in pygame?

Question

Here I, have am tying to simply make 2 rectangles using pygame module. I have made them using 2 methods but they don't seem to work. Please suggest some that could work. (I am using Python 3.8.3)

Here is the code:

import pygame
pygame.init()

screen = pygame.display.set_mode((100, 100))

box_color = (255, 0, 0)
color = (0, 150, 100)

ybox = 20
xbox = 20

running = True
while running:
for event in pygame.event.get():
    if event.type == pygame.QUIT:
        running = False
        
    if event.type == pygame.KEYDOWN:
                                                             
        ybox += 5


    if (ybox >= 45):
        ybox = 45                                                               
pygame.draw.rect(screen, box_color, pygame.Rect(xbox, ybox, 50, 50), 2)
pygame.display.flip()

pygame.draw.rect(screen, box_color, pygame.Rect(20, 95, 50, 50), 2)
pygame.display.flip()

screen.fill(color)
pygame.display.update()

score 3 · Accepted Answer · answered Mar 27 '21 at 12:57

Your game is flickering because of the multiple calls of pygame.display.flip() and pygame.display.update(). One update of the display at the end of the application loop is sufficient. Multiple calls to pygame.display.update() or pygame.display.flip() cause flickering.

Remove all calls of pygame.display.update() and pygame.display.flip() from your code, but call it once at the end of the application loop. However, clear the display before drawing the objects:

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        if event.type == pygame.KEYDOWN:
            ybox += 5
        if (ybox >= 45):
            ybox = 45                                                               

    # clear disaply
    screen.fill(color)

    # draw objects
    pygame.draw.rect(screen, box_color, pygame.Rect(xbox, ybox, 50, 50), 2)
    pygame.draw.rect(screen, box_color, pygame.Rect(20, 95, 50, 50), 2)

    # update dispaly
    pygame.display.update()

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()

How to fix flickering of objects and figures in pygame?

1 Answers1