在 Pygame 中使用多处理时出错答案

【问题标题】：Error while using multiprocessing in Pygame在 Pygame 中使用多处理时出错
【发布时间】：2022-12-22 07:18:38
【问题描述】：

我正在制作基于文本的角色扮演游戏，并尝试使用多处理同时运行 pygame 检查功能和游戏功能。这是我第一次使用多处理，所以我不完全确定发生了什么。

这是（重要的）代码：

from csv import reader
import pygame
from sys import exit
import multiprocessing

def check():
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            exit()

def startgame():
    play(input("Present Command\n"))

play_game_process = multiprocessing.Process(target=startgame)
play_game_process.start()

check_process = multiprocessing.Process(target=check)
check_process.start()

当我运行代码时，我遇到了一条非常大的错误消息：

pygame 2.1.2 (SDL 2.0.18, Python 3.10.8)
Hello from the pygame community. https://www.pygame.org/contribute.html
pygame 2.1.2 (SDL 2.0.18, Python 3.10.8)
Hello from the pygame community. https://www.pygame.org/contribute.html
pygame 2.1.2 (SDL 2.0.18, Python 3.10.8)
Hello from the pygame community. https://www.pygame.org/contribute.html
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 116, in spawn_main
    exitcode = _main(fd, parent_sentinel)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 125, in _main
    prepare(preparation_data)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 236, in prepare
    _fixup_main_from_path(data['init_main_from_path'])
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 287, in _fixup_main_from_path
    main_content = runpy.run_path(main_path,
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\runpy.py", line 289, in run_path
    return _run_module_code(code, init_globals, run_name,
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\runpy.py", line 96, in _run_module_code
    _run_code(code, mod_globals, init_globals,
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "c:\Users\Dougl\Documents\Coding\Python\games\Command\command.py", line 193, in <module>
    play_game_process.start()
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\process.py", line 121, in start
    self._popen = self._Popen(self)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\context.py", line 224, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\context.py", line 336, in _Popen
    return Popen(process_obj)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\popen_spawn_win32.py", line 45, in __init__
    prep_data = spawn.get_preparation_data(process_obj._name)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 154, in get_preparation_data
    _check_not_importing_main()
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 134, in _check_not_importing_main
    raise RuntimeError('''
RuntimeError:
        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.

        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:

            if __name__ == '__main__':
                freeze_support()
                ...

        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 116, in spawn_main
    exitcode = _main(fd, parent_sentinel)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 125, in _main
    prepare(preparation_data)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 236, in prepare
    _fixup_main_from_path(data['init_main_from_path'])
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 287, in _fixup_main_from_path
    main_content = runpy.run_path(main_path,
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\runpy.py", line 289, in run_path
    return _run_module_code(code, init_globals, run_name,
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\runpy.py", line 96, in _run_module_code
    _run_code(code, mod_globals, init_globals,
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "c:\Users\Dougl\Documents\Coding\Python\games\Command\command.py", line 193, in <module>
    play_game_process.start()
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\process.py", line 121, in start
    self._popen = self._Popen(self)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\context.py", line 224, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\context.py", line 336, in _Popen
    return Popen(process_obj)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\popen_spawn_win32.py", line 45, in __init__
    prep_data = spawn.get_preparation_data(process_obj._name)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 154, in get_preparation_data
    _check_not_importing_main()
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.10_3.10.2288.0_x64__qbz5n2kfra8p0\lib\multiprocessing\spawn.py", line 134, in _check_not_importing_main
    raise RuntimeError('''
RuntimeError:
        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.

        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:

            if __name__ == '__main__':
                freeze_support()
                ...

        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.

我不确定这里发生了什么，如果可以的话请帮忙！

【问题讨论】：

You can't access the event loop from another thread。我建议完全避免使用线程，因为 pygame 会为您创建必要的线程。

标签： python pygame multiprocessing python-multiprocessing

【解决方案1】：

您是否阅读了错误消息的末尾以及那里非常明确的说明？使用多处理时，您的主要代码需要包装在 if __name__ == "__main__": 习语中（这也记录在 multiprocessing 文档中）。

IE。就像是

import multiprocessing
from sys import exit

import pygame


def check():
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            exit()


def startgame():
    play(input("Present Command
"))


def main():
    play_game_process = multiprocessing.Process(target=startgame)
    play_game_process.start()

    check_process = multiprocessing.Process(target=check)
    check_process.start()


if __name__ == '__main__':
    main()

但是请注意，这可能不会执行您想要的操作，因为 check 和 startgame 函数将在完全不同的过程根本不了解彼此。

【讨论】：

非常感谢您的评论，它真的帮助了我。现在唯一的问题是当我尝试运行更新后的代码时，pygame 窗口启动了三次，然后立即崩溃。它没有给我任何错误消息，所以我知道语法是有效的，但我不确定哪里出错了。这是窗口的代码：
``` background_colour = (0,0,0) width, height = 1920, 1080 screen = pygame.display.set_mode((width,height)) pygame.display.set_caption("Command") screen.fill(background_colour) pygame .display.flip() ``` 这是运行循环的代码：``` for event in pygame.event.get(): if event.type == pygame.QUIT: pygame.quit() exit( ）```
该初始化代码应该在 main 函数中，因此您不会初始化三个 Pygames（一个在父项中，两个在子项中）——但同样，您真的不想为此使用 multiprocessing。
谢谢你。出于兴趣，我如何在没有多处理的情况下执行相同的代码？
@Crazyscientist09 您不能（在合理范围内）在事件驱动（即 GUI）应用程序中使用阻塞代码。 input 阻止执行，所以你根本不应该使用它。