Pygame display does not update

Question

I am making a game in pygame, but the display doesn't update. I am using the update() function and am clearing the screen at the beginning of the loop with fill(). Pygame also does not load very quickly; I have to hit "quit" on the pygame application once it shows in the running applications on my mac for the screen to appear.

"Module Imports"
import pygame as pg
import shelve

"Import Classes"
from Settings import Settings
from Settings import Screen
from Settings import Save
from Random import Random
from Input import Input
from Input import Button
# Init Classes
Settings = Settings()
Screen = Screen()
Random = Random()
Save = Save()

on = True

pg.init()

event_const = pg.event.wait()

save_file = shelve.open("/Volumes/HISTORYGAME/Game_Saves/Save_File")

clock = pg.time.Clock()
MainDisplay = pg.display.set_mode((Screen.width, Screen.height))
pg.display.set_caption(Settings.title)
pg.display.init()


class Mouse:
    def __init__(self):
        self.left = False
        self.right = False


Mouse = Mouse()


def begin_game():
    players = []
    num_players = input("How Many Players (enter int): ")

    save_file["num_players_var"] = num_players

    for pl in range(num_players):
        players.append(raw_input("Enter Player Name: "))

    save_file["players_var"] = players

    print(players)


def intro():
    intro = True

    for event in pg.event.get():
        if event.get == pg.QUIT:
            intro = False
            on = False
        if event.get == pg.event.KEYDOWN:
            pass


# begin_game()

test_button = Button(0, 0, 200, 200, "Enter Text Here", MainDisplay)
buttons = []
buttons.append(test_button)

loops = 0

test_x = 10
test_y = 10

while on:
    MainDisplay.fill((0, 0, 0))
    for event in pg.event.get():
        if event.type == pg.QUIT:
            On = False
            pg.quit()
            exit()
        if event.type == pg.KEYDOWN:
            if event.key == pg.K_ESCAPE:
                On = False
                pg.quit()
                exit()
            if event.key == pg.K_RIGHT:
                test_x += 10
                print("right")
        if event.type == pg.MOUSEBUTTONDOWN:
            if event.button == 1:
                Mouse.left = True
            else:
                Mouse.left = False
        if event.type == pg.MOUSEBUTTONUP:
            if event.button == 1:
                Mouse.left = False

    for button in buttons:
        button.draw(pg.mouse.get_pos(), event_const)
        if button.clicked is True:
            print("True \n" * 100)

    pg.draw.line(MainDisplay, (255, 0, 0), (100, 100), (600, 600))
    pg.draw.rect(MainDisplay, (255, 0, 0), (test_x, test_y, 20, 20))

    pg.display.flip()
    pg.display.update()
    clock.tick(Settings.FPS)
    loops += 1
    print(str(loops))

That first event_const = pg.event.wait(), why does the code have this? This causes pygame to wait for an event. But the main window isn't initialised - so this will either do nothing, or cause the program to hang. — Kingsley
@kingsley thanks, I thought that was a way to test for any event later without a for loop. Is there another way to do this? — Caleb Kopitsky
Maybe just move it to after the window is initialised (before class Mouse) — Kingsley
@kingsley the problem persists even with this troubleshooting — Caleb Kopitsky
Update: I have fixed the issue with the display starting but it is still just blank — Caleb Kopitsky

Kingsley Kingsley · Accepted Answer · 2020-02-16T21:46:37

I suspect the waiting for an event, or reading of the stdin with input() is causing a lockup issue. But in the presented code, the call to this is commented-out. It's not possible to really know.

This version of the code, with a re-created Button class works ok, but obviously it doesn't have any of the referenced classes.

"Module Imports"
import pygame 
#import shelve

"Import Classes"
#from Settings import Settings
#from Settings import Screen
#from Settings import Save
#from Random import Random
#from Input import Input
#from Input import Button
# Init Classes
#Settings = Settings()
#Screen = Screen()
#Random = Random()
#Save = Save()

WINDOW_WIDTH  = 600
WINDOW_HEIGHT = 600

class Mouse:
    def __init__(self):
        self.left = False
        self.right = False

class Button:
    def __init__( self, x, y, width, height, label, window ):
        self.rect    = pygame.Rect( x, y, width, height )
        self.clicked = False
        self.window  = window
        self.font    = pygame.font.Font( None, 20 )
        self.label   = self.font.render( label, True, ( 255, 255, 255 ) ) # large white text

    def draw( self, mouse_pos ):
        if ( self.rect.collidepoint( mouse_pos ) ):
            colour = ( 0, 200, 0 )  # green if mouse over
        else:
            colour = (0, 0, 200)    # blue otherwise
        pygame.draw.rect( self.window, colour, self.rect, 0 )  # filled rectangle
        # centred text
        label_rect = self.label.get_rect()
        x_offset = ( self.rect.width  - label_rect.width ) // 2
        y_offset = ( self.rect.height - label_rect.height ) // 2
        self.window.blit( self.label, ( x_offset, y_offset ) )

    def checkClick( self, mouse_pos ):
        if ( self.rect.collidepoint( mouse_pos ) ):
            self.clicked = True
        else:
            self.clicked = False


def begin_game():
    players = [ "Mork", "Mindy", "E.T." ]   # test data
    #players = []
    #num_players = input("How Many Players (enter int): ")
    #save_file["num_players_var"] = num_players
    #for pl in range(num_players):
    #    players.append(raw_input("Enter Player Name: "))
    #save_file["players_var"] = players
    print(players)




# Initialisation
pygame.init()
pygame.font.init()
#event_const = pygame.event.wait()
#save_file = shelve.open("/Volumes/HISTORYGAME/Game_Saves/Save_File")
clock = pygame.time.Clock()
window = pygame.display.set_mode( ( WINDOW_WIDTH, WINDOW_HEIGHT ) )
pygame.display.set_caption( "Settings.title" )
pygame.display.init()



Mouse = Mouse()
begin_game()
test_button = Button(0, 0, 200, 200, "Enter Text Here", window)
buttons = []
buttons.append(test_button)

loops = 0
test_x = 10
test_y = 10

on = True
while on:
    window.fill((0, 0, 0))
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            on = False
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_ESCAPE:
                on = False
            elif event.key == pygame.K_RIGHT:
                test_x += 10
                print("right")
        elif event.type == pygame.MOUSEBUTTONDOWN:
            if event.button == 1:
                Mouse.left = True
        elif event.type == pygame.MOUSEBUTTONUP:
            if event.button == 1:
                Mouse.left = False
                for button in buttons:
                    button.checkClick( event.pos )  # buttons actuate on mouse-up

    for button in buttons:
        button.draw( pygame.mouse.get_pos() ) #, event_const)
        if button.clicked is True:
            print("True \n" * 5) # 100

    pygame.draw.line(window, (255, 0, 0), (100, 100), (600, 600))
    pygame.draw.rect(window, (255, 0, 0), (test_x, test_y, 20, 20))

    pygame.display.flip()
    #pygame.display.update()   # only need update() or flip()
    clock.tick( 60 ) #Settings.FPS)
    loops += 1
    #print(str(loops))   # Too noisy

# exiting
pygame.quit()

Pygame display does not update

1 Answers