Pygame Playlist Continuous in the Background [dupl

问题:

This question already has an answer here:

• How do I schedule an audio file to play automatically in pygame after the first song ends? 1 answer

I'm trying to get background music for my game, but I can't seem to figure it out perfectly. I've used pygame in the past, but it was only for one song during the credits of my game. I want the playlist to play continuously picking each track randomly. I've managed to get this working in a separate test file. I will post this code down below.

The problem is when I call this function in my main game, the music plays the first track, and then stops. If I put in

while pygame.mixer.music.get_busy():
    continue

It just plays the music and doesn't let me play the game. I want it to loop continuously through the playlist while the user plays the game (it's a text based game so it uses raw_input() a lot.

Here is my code:

import pygame
import random

pygame.mixer.init()

_songs = [songs, are, here]

_currently_playing_song = None

def music():
    global _currently_playing_song, _songs
    next_song = random.choice(_songs)
    while next_song == _currently_playing_song:
        next_song = random.choice(_songs)
    _currently_playing_song = next_song
    pygame.mixer.music.load(next_song)
    pygame.mixer.music.play()

while True: ## This part works for the test, but will not meet my needs
    music() ## for the full game.
    while pygame.mixer.music.get_busy():
        continue

(P.S. I learned python through Zed Shaw's "Learn Python The Hard Way" so my game structure uses the Engine and Map system from the book)

回答1:

You can use a thread to play music in the background.

import threading
musicThread = threading.Thread(target=music)
musicThread.start()

If you ever want to stop the music without closing your game, you should kill the thread.

回答2:

You can set a pygame.mixer.music.set_endevent() which get posted in the event queue when the music finishes. Then you just choose another song. Something along these lines:

import os
import pygame
pygame.init()
pygame.mixer.init()

SIZE = WIDTH, HEIGHT = 720, 460
screen = pygame.display.set_mode(SIZE)

MUSIC_ENDED = pygame.USEREVENT
pygame.mixer.music.set_endevent(MUSIC_ENDED)


BACKGROUND = pygame.Color('black')


class Player:

    def __init__(self, position):
        self.position = pygame.math.Vector2(position)
        self.velocity = pygame.math.Vector2()

        self.image = pygame.Surface((32, 32))
        self.rect =  self.image.get_rect(topleft=self.position)

        self.image.fill(pygame.Color('red'))

    def update(self, dt):
        self.position += self.velocity * dt
        self.rect.topleft = self.position


def load_music(path):
    songs = []
    for filename in os.listdir(path):
        if filename.endswith('.wav'):
            songs.append(os.path.join(path, filename))
    return songs


def run():
    songs = load_music(path='/Users/Me/Music/AwesomeTracks')

    song_index = 0  # The current song to load
    pygame.mixer.music.load(songs[song_index])
    pygame.mixer.music.play()
    song_index += 1

    clock = pygame.time.Clock()
    player = Player(position=(WIDTH / 2, HEIGHT / 2))

    while True:
        dt = clock.tick(30) / 1000

        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                quit()
            elif event.type == pygame.KEYDOWN:
                if event.key == pygame.K_a:
                    player.velocity.x = -200
                elif event.key == pygame.K_d:
                    player.velocity.x = 200
                elif event.key == pygame.K_w:
                    player.velocity.y = -200
                elif event.key == pygame.K_s:
                    player.velocity.y = 200
            elif event.type == pygame.KEYUP:
                if event.key == pygame.K_a or event.key == pygame.K_d:
                    player.velocity.x = 0
                elif event.key == pygame.K_w or event.key == pygame.K_s:
                    player.velocity.y = 0
            elif event.type == MUSIC_ENDED:
                song_index = (song_index + 1) % len(songs)  # Go to the next song (or first if at last).
                pygame.mixer.music.load(songs[song_index])
                pygame.mixer.music.play()

        screen.fill(BACKGROUND)

        player.update(dt)
        screen.blit(player.image, player.rect)

        pygame.display.update()

run()

So the actual solution is just 3 parts

1. Create an event MUSIC_ENDED = pygame.USEREVENT.
2. Tell pygame to post the event when a song finishes pygame.mixer.music.set_endevent(MUSIC_ENDED)
3. Check for the event in the event queue for event in pygame.event.get(): if event.type == MUSIC_ENDED:

And then you're free to do whatever you desire.