import pygame



def run_game():
    
    ## Initialize the pygame submodules and set up the display window.
    pygame.init()

    width = 640
    height = 480
    game_window = pygame.display.set_mode((width,height))

    # load the images and convert into Pygame's internal image format
    guy_pics = [pygame.image.load("WalkingSquare1.gif"),
                pygame.image.load("WalkingSquare2.gif"),
                pygame.image.load("WalkingSquare3.gif"),
                pygame.image.load("WalkingSquare4.gif"),
                pygame.image.load("WalkingSquare5.gif")]
    for index in range(0,len(guy_pics)):
        guy_pics[index] = guy_pics[index].convert()

    guy_x = 100
    guy_y = 100

    anim_counter = 0
    anim_threshold = 70
    cur_idx = 0
    
    ## The game loop starts here.
    keepGoing = True    
    while (keepGoing):

        ## Handle events.
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                keepGoing = False

        anim_counter += 1
        if anim_counter > anim_threshold:
            cur_idx = (cur_idx + 1) % 5
            anim_counter = 0
            
        ## Draw picture and update display
        game_window.fill(pygame.color.Color("yellowgreen"))

        game_window.blit(guy_pics[cur_idx],(guy_x,guy_y))

        pygame.display.update()


    ## The game loop ends here.
    pygame.quit()


## Call the function run_game.
run_game()