How can i solve this: my image doesn't appear on the screen

Question

import sys

import pygame

(width, height) = (800, 600)
screen = pygame.display.set_mode((width, height))
pygame.display.flip()

#Title and Icon
pygame.display.set_caption("Space Invader")
icon = pygame.image.load("spaceship.png")
pygame.display.set_icon(icon)

#Player
playerImg = pygame.image.load("player.png")
playerX = 370
playerY = 480
player_change = 0


def player(x, y):
    screen.blit(playerImg, (x, y))


#Game loop
running = True
while running:
    while running:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                sys.exit()
        pygame.display.flip()

        #RGB- Red, Green, Blue
        screen.fill((0, 128, 128))

# if keystroke is pressed check whether its right or left
        if event.type == pygame.KEYDOWN:
                 if event.key == pygame.K_LEFT:
                     playerX_change = -0.1
                 if event.key == pygame.K_RIGHT:
                     playerX_change = 0.1
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                playerX_change = 0.1

    # 5 = 5 + -0.1 -> 5 = 5 -0.1
    # 5 = 5 + 0.1
    playerX += playerX_change
    player(playerX, playerY)
    pygame.display.update()

New atcoding so I followed this youtube video and there his image loaded and mine did too at first. But later if I added these lines of code, it stopped appearing on the screen. I followed his instructions step by step.

 if event.type == pygame.KEYDOWN:
                 if event.key == pygame.K_LEFT:
                     playerX_change = -0.1
                 if event.key == pygame.K_RIGHT:
                     playerX_change = 0.1
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                playerX_change = 0.1

How can i solve this problem

Rabbid76 · Answer 1 · 2021-12-18T13:07:02.713

You just need 1 application loop. All the events must be handled in the event loop. You have to correct the Indentation.
Also see How to get keyboard input in pygame?:

speed = 1 

# application loop
clock = pygame.time.Clock() 
running = True
while running:
    clock.tick(100)

    # event loop
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
            
    keys = pygame.key.get_pressed()
    playerX += (keys[pygame.K_RIGHT] - keys[pygame.K_LEFT]) * speed       

    # clear display
    screen.fill((0, 128, 128))

    # draw scene 
    player(playerX, playerY)

    # update diesplay
    pygame.display.update()

pygame.quit()
sys.exit()

The typical PyGame application loop has to:

limit the frames per second to limit CPU usage with pygame.time.Clock.tick
handle the events by calling 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 calling either pygame.display.update() or pygame.display.flip()

score 0 · Answer 2 · answered Dec 18 '21 at 10:41

while running:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                sys.exit()
        pygame.display.flip()

        #RGB- Red, Green, Blue
        screen.fill((0, 128, 128))

# if keystroke is pressed check whether its right or left
        if event.type == pygame.KEYDOWN:
                 if event.key == pygame.K_LEFT:
                     playerX_change = -0.1
                 if event.key == pygame.K_RIGHT:
                     playerX_change = 0.1
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                playerX_change = 0.1

        # **This code is outside of main loop**
        playerX += playerX_change
        player(playerX, playerY)
        pygame.display.update()

You are running main loop twice(while running) and the new code you added was out of it's scope.

How can i solve this: my image doesn't appear on the screen

2 Answers2