screen.fill doesn't seem to work

Question

I've ben programming a game and everything works so now I want is a screen before the game starts. You must then click on start to proceed to the game. So far I have this code:

if menu == 'start':
    screen.fill((0,255,0))
    txt = font.render('Start',True,(255,255,0))
    txt_x = 480
    txt_y = 290
    buttonrect = pygame.Rect((txt_x,txt_y),txt.get_size())
    pygame.draw.rect(screen,(0,0,255),buttonrect)
    screen.blit(txt,(txt_x,txt_y))
    if pygame.mouse.get_pressed()[0] and buttonrect.collidepoint(pygame.mouse.get_pos()):
        menu = 'game'

I've set menu to 'start' but it doesn't work. The screen is black instead of green. But when I click on the coordinates, I go to the game. What is wrong with my code?

Answer 1

You need to update the main display after setting the screen background :

if menu == 'start':
    screen.fill((0,255,0))
    txt = font.render('Start',True,(255,255,0))
    txt_x = 480
    txt_y = 290
    buttonrect = pygame.Rect((txt_x,txt_y),txt.get_size())
    pygame.draw.rect(screen,(0,0,255),buttonrect)
    screen.blit(txt,(txt_x,txt_y))

    pygame.display.update()

    if pygame.mouse.get_pressed()[0] and buttonrect.collidepoint(pygame.mouse.get_pos()):
        menu = 'game'