¿Por qué el bucle de mi aplicación pygame no funciona correctamente?

Estoy trabajando en un juego de aventuras 2D de arriba hacia abajo muy aproximado después de hojear la documentación de pygame. Sin embargo, me encontré con un obstáculo después de no poder encontrar nada en un sistema de cámara y descubrí que la mayoría de los tutoriales para una cámara tienen más de 5 años y ya no parecen funcionar. ¿Alguien puede ayudarme a construir una cámara?

Este es mi script principal ejecutado.

import sys, pygame
from PlayerObject import Player

pygame.init()

screen_height = 180
screen_width = 320
map_height = 1080
map_width = 1920

num_objects = 5

screen = pygame.display.set_mode((screen_width, screen_height))
player_image = pygame.image.load('models/hero.bmp').convert()
background = pygame.image.load('models/lobby.bmp').convert()
screen.blit(background, (0, 0))
objects = []

# randomly generates 5 entities with the 1st one being the controlled character
for i in range(num_objects):
    o = Player(player_image, random.randint(0, screen_width), random.randint(0, screen_height), 10)
    objects.append(o)

while 1:

    keys = pygame.key.get_pressed()
    if keys[pygame.K_LEFT]:
        screen.blit(background, objects[0].pos, objects[0].pos)
        objects[0].move_left()
        screen.blit(objects[0].image, objects[0].pos)
    if keys[pygame.K_RIGHT]:
        screen.blit(background, objects[0].pos, objects[0].pos)
        objects[0].move_right()
        screen.blit(objects[0].image, objects[0].pos)
    if keys[pygame.K_UP]:
        screen.blit(background, objects[0].pos, objects[0].pos)
        objects[0].move_up()
        screen.blit(objects[0].image, objects[0].pos)
    if keys[pygame.K_DOWN]:
        screen.blit(background, objects[0].pos, objects[0].pos)
        objects[0].move_down()
        screen.blit(objects[0].image, objects[0].pos)
        screen.blit(background)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()

    for o in objects:
        screen.blit(background, o.pos, o.pos)
    for num in range(num_objects - 1):
        objects[num + 1].rand_move()
    for o in objects:
        screen.blit(o.image, o.pos)

    pygame.display.update()
    pygame.time.delay(100)

Esta es mi clase de jugador.

import random

map_height = 180
map_width = 320

class Player:
    def __init__(self, image, width, height, speed):
        self.speed = speed
        self.image = image
        self.pos = image.get_rect().move(width, height)
        self.image = image

    def set_speed(self, speed):
        self.speed = speed

    def rand_move(self):
        x = random.randint(-self.speed, self.speed)
        y = random.randint(-self.speed, self.speed)
        self.pos = self.pos.move(x, y)

        # keeps player in boundaries
        if self.pos.left < 0:
            self.pos.left = 0
        if self.pos.right > map_width:
            self.pos.right = map_width
        if self.pos.top < 0:
            self.pos.top = 0
        if self.pos.bottom > map_height:
            self.pos.bottom = map_height

    def move_left(self):
        speed = self.speed
        self.pos = self.pos.move(-speed, 0)
        if self.pos.left < 0:
            self.pos.left = 0

    def move_right(self):
        speed = self.speed
        self.pos = self.pos.move(speed, 0)
        if self.pos.right > map_width:
            self.pos.right = map_width

    def move_up(self):
        speed = self.speed
        self.pos = self.pos.move(0, -speed)
        if self.pos.top < 0:
            self.pos.top = 0

    def move_down(self):
        speed = self.speed
        self.pos = self.pos.move(0, speed)
        if self.pos.bottom > map_height:
            self.pos.bottom = map_height

Feb 25 '20 11:02 AsianTemptation