Cy Run Running Game

import pygame
from sys import exit
from random import randint

def display_score():
    current_time = int(pygame.time.get_ticks() / 1000)- start_time
    score_surf = font.render(f'{current_time}',False,('#ffffff'))
    score_rect = score_surf.get_rect(center = (400,50))
    screen.blit(score_surf,score_rect)
    return current_time

def obstacle_movement(obstacle_list):
    if obstacle_list:
        for obstacle_rect in obstacle_list:
            obstacle_rect.x -= 5

            if obstacle_rect.bottom == 315:
                screen.blit(bcat_surf,obstacle_rect)
            else: screen.blit(bat_surf,obstacle_rect)

        obstacle_list = [obstacle for obstacle in obstacle_list if obstacle.x > -100]

        return obstacle_list
    else: return []

def collisions(player, obstacles):
    if obstacles:
        for obstacle_rect in obstacles:
            if player.colliderect(obstacle_rect):
                return False
    return True

def player_animation():
    global player_surf, player_index

    if player_rect.bottom < 250:
        player_surf = player_jump
    else:
        player_index += 0.1
        if player_index>= len(player_walk):player_index = 0
        player_surf = player_walk[int(player_index)]
        player_surf = pygame.transform.scale(player_surf, (115, 160))


pygame.init()
screen = pygame.display.set_mode((800,400))
pygame.display.set_caption('Cy Run')
clock = pygame.time.Clock()
font = pygame.font.Font('fonts/Pixeltype.ttf', 50)
font2 = pygame.font.Font('fonts/Arcade.otf', 50)
game_active = False
start_time = 0
score = 0

title_music = pygame.mixer.Sound('audio/Title.mp3')
game_music = pygame.mixer.Sound('audio/Mos_Eisley_Cantina.mp3')
bg_music_playing = False

icon_image = pygame.image.load('graphics/icon.png')
pygame.display.set_icon(icon_image)

startbg_surf = pygame.image.load('graphics/Start.png').convert()

sky_surface = pygame.image.load('graphics/Sky.png').convert()
sky_x_pos = 0

ground_surf = pygame.image.load('graphics/ground.png').convert()
ground_x_pos = 0
ground_y_pos = screen.get_height() - ground_surf.get_height() + 24

#bcat
bcat_1 = pygame.image.load('graphics/bcat/bcat1.png').convert_alpha()
bcat_1 = pygame.transform.scale(bcat_1, (67,67))
bcat_2 = pygame.image.load('graphics/bcat/bcat2.png').convert_alpha()
bcat_2 = pygame.transform.scale(bcat_2, (67,67))
bcat_3 = pygame.image.load('graphics/bcat/bcat3.png').convert_alpha()
bcat_3 = pygame.transform.scale(bcat_3, (67,67))
bcat_4 = pygame.image.load('graphics/bcat/bcat4.png').convert_alpha()
bcat_4 = pygame.transform.scale(bcat_4, (67,67))
bcat_frames = [bcat_1,bcat_2,bcat_3,bcat_4]
bcat_index = 0
bcat_surf = bcat_frames[bcat_index]

#bat
bat_1 = pygame.image.load('graphics/bat/bat1.png').convert_alpha()
bat_1 = pygame.transform.scale(bat_1, (80,80))
bat_2 = pygame.image.load('graphics/bat/bat2.png').convert_alpha()
bat_2 = pygame.transform.scale(bat_2, (80,80))
bat_3 = pygame.image.load('graphics/bat/bat3.png').convert_alpha()
bat_3 = pygame.transform.scale(bat_3, (80,80))
bat_4 = pygame.image.load('graphics/bat/bat4.png').convert_alpha()
bat_4 = pygame.transform.scale(bat_4, (80,80))
bat_frames = [bat_1,bat_2,bat_3,bat_4]
bat_index = 0
bat_surf = bat_frames[bat_index]

obstacle_rect_list = []

player_walk1 = pygame.image.load('graphics/player/player_walk1.png').convert_alpha()
player_walk2 = pygame.image.load('graphics/player/player_walk2.png').convert_alpha()
player_walk3 = pygame.image.load('graphics/player/player_walk3.png').convert_alpha()
player_walk = [player_walk1,player_walk2,player_walk3]
player_index = 0
player_jump = pygame.image.load('graphics/player/jump.png').convert_alpha()
player_jump = pygame.transform.scale(player_jump, (115, 160))
player_surf = player_walk[player_index]
player_rect = player_surf.get_rect(midbottom = (80,300))
player_gravity = 0

player_stand = pygame.image.load('graphics/player/player_stand.png').convert_alpha()
player_stand = pygame.transform.scale2x(player_stand)
player_stand_rect = player_stand.get_rect(center = (400,200))

game_name = font.render ('Cy Run', False, ('#ffffff'))
game_name_rect = game_name.get_rect(center = (400,80))

game_message = font2.render('PRESS SPACE TO RUN', False,('#ffffff'))
game_message = pygame.transform.scale(game_message, (int(game_message.get_width() * 0.4), int(game_message.get_height() * 0.4)))
game_message_rect = game_message.get_rect(midright = (750,365))

#obs timer
obstacle_timer = pygame.USEREVENT + 1
pygame.time.set_timer(obstacle_timer,1500)

bcat_ani_timer = pygame.USEREVENT +2
pygame.time.set_timer(bcat_ani_timer,200)

bat_ani_timer = pygame.USEREVENT +3
pygame.time.set_timer(bat_ani_timer,200)

title_music.play()

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            exit()

        if game_active:
            if event.type == pygame.MOUSEMOTION:
                if player_rect.collidepoint(event.pos):
                    player_gravity = -20

            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_SPACE and player_rect.bottom >= 250:
                    player_gravity = -20
        else:
            if event.type == pygame.KEYDOWN and event.key == pygame.K_SPACE:
                game_active = True
                start_time = int(pygame.time.get_ticks() / 1000)
                bg_music_playing = False
                title_music.play()

        if game_active:
            if event.type == obstacle_timer and game_active:
                if randint(0,2):
                    obstacle_rect_list.append(bcat_surf.get_rect(bottomright=(randint(900,1100),315)))
                else:
                    obstacle_rect_list.append(bat_surf.get_rect(bottomright=(randint(900,1100),160)))
            if event.type == bcat_ani_timer:
                if bcat_index == 0: bcat_index = 1
                else: bcat_index = 0
                bcat_surf = bcat_frames[bcat_index]
            if event.type == bat_ani_timer:
                if bat_index == 0: bat_index = 1
                else: bat_index = 0
                bat_surf = bat_frames[bat_index]


    if game_active:

        sky_surface = pygame.transform.scale(sky_surface, (800, 300))
        screen.blit(sky_surface, (sky_x_pos, 0))
        screen.blit(sky_surface, (sky_x_pos + sky_surface.get_width(), 0))

        sky_x_pos -= 2
        if sky_x_pos <= -sky_surface.get_width():
            sky_x_pos = 0

        score = display_score()

        ground_surf = pygame.transform.scale(ground_surf, (800, screen.get_height() - ground_y_pos))
        screen.blit(ground_surf, (ground_x_pos, ground_y_pos))
        screen.blit(ground_surf, (ground_x_pos + ground_surf.get_width(), ground_y_pos))

        ground_x_pos -= 2
        if ground_x_pos <= -ground_surf.get_width():
            ground_x_pos = 0

        #player
        player_gravity += 1.2
        player_rect.y += player_gravity
        if player_rect.bottom >= 250: player_rect.bottom = 250
        player_animation()
        screen.blit(player_surf, player_rect)

        #obstacle movement

        obstacle_rect_list = obstacle_movement(obstacle_rect_list)

        #collision
        game_active = collisions(player_rect,obstacle_rect_list)

        if not bg_music_playing:
            game_music.play()
            bg_music_playing = True
            title_music.stop()

    else:
        startbg_surf = pygame.transform.scale(startbg_surf, (800, 400))
        screen.blit(startbg_surf, (0, 0))
        obstacle_rect_list.clear()
        player_rect.midbottom = (80,300)
        player_gravity = 0

        score_message = font.render(f'Score: {score}',False,('#ffffff'))
        score_message_rect = score_message.get_rect(midright = (750,365))

        if score == 0:
            screen.blit(game_message,game_message_rect)
        else:
            screen.blit(score_message,score_message_rect)

        if bg_music_playing:
            game_music.stop()
            bg_music_playing = False
            title_music.play()

    pygame.display.update()
    clock.tick(60)