无法在 macos 上的 python 中导入 opengl.gl

Question

我正在使用 OpenGL 在 python 中渲染场景。我的代码在 Windows 上运行良好，但由于某种原因，我在 MacOS 上导入 opengl.gl 时遇到问题。

from OpenGL.GL import ...在同时调用python 脚本和 python 控制台时会出现问题。

更具体地说，这里是我脚本中的确切调用：

from OpenGL.GL import glGenBuffers, glBindBuffer, glBufferData, \
    glGenVertexArrays, glBindVertexArray, glEnableVertexAttribArray, glVertexAttribPointer, \
    glDrawArrays, glUseProgram, glEnable, glDisable, \
    GL_ARRAY_BUFFER, GL_STATIC_DRAW, GL_DEPTH_TEST, \
    GL_FLOAT, GL_FALSE, \
    GL_TRIANGLES, GL_LINES, GL_LINE_STRIP

这会导致以下错误：

       Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/darwin.py", line 35, in GL
    return ctypesloader.loadLibrary(
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/ctypesloader.py", line 36, in loadLibrary
    return _loadLibraryWindows(dllType, name, mode)
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/ctypesloader.py", line 89, in _loadLibraryWindows
    return dllType( name, mode )
  File "/usr/local/Cellar/python@3.8/3.8.5/Frameworks/Python.framework/Versions/3.8/lib/python3.8/ctypes/__init__.py", line 373, in __init__
    self._handle = _dlopen(self._name, mode)
OSError: ('dlopen(OpenGL, 10): image not found', 'OpenGL', None)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/iyadboustany/Desktop/lensmaster/Lensmaster.py", line 18, in <module>
    from MainWindow import MainWindow
  File "/Users/iyadboustany/Desktop/lensmaster/MainWindow.py", line 14, in <module>
    from Robot import Robot
  File "/Users/iyadboustany/Desktop/lensmaster/Robot.py", line 8, in <module>
    from Graphics.Scene import DHNode
  File "/Users/iyadboustany/Desktop/lensmaster/Graphics/Scene.py", line 13, in <module>
    from OpenGL.GL import glGenBuffers, glBindBuffer, glBufferData, \
  File "/usr/local/lib/python3.8/site-packages/OpenGL/GL/__init__.py", line 3, in <module>
    from OpenGL import error as _error
  File "/usr/local/lib/python3.8/site-packages/OpenGL/error.py", line 12, in <module>
    from OpenGL import platform, _configflags
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/__init__.py", line 36, in <module>
    _load()
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/__init__.py", line 33, in _load
    plugin.install(globals())
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/baseplatform.py", line 97, in install
    namespace[ name ] = getattr(self,name,None)
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/baseplatform.py", line 15, in __get__
    value = self.fget( obj )
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/darwin.py", line 62, in GetCurrentContext
    return self.CGL.CGLGetCurrentContext 
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/baseplatform.py", line 15, in __get__
    value = self.fget( obj )
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/darwin.py", line 45, in CGL
    def CGL(self): return self.GL
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/baseplatform.py", line 15, in __get__
    value = self.fget( obj )
  File "/usr/local/lib/python3.8/site-packages/OpenGL/platform/darwin.py", line 41, in GL
    raise ImportError("Unable to load OpenGL library", *err.args)
ImportError: ('Unable to load OpenGL library', 'dlopen(OpenGL, 10): image not found', 'OpenGL', None)

注意事项：

• 运行 glxgears 工作得很好。
• 我正在运行 macOS Big Sur 测试版 (20A5343i)
• 我正在使用 python 3.8.5
• 我使用 pip 安装了 opengl： pip3 install PyOpenGL PyOpenGL_accelerate

Answer 1

这个错误是因为 Big Sur 在文件系统的标准位置不再有 OpenGL 库和其他系统库，而是使用缓存。PyOpenGL 使用 ctypes 尝试定位 OpenGL 库，但找不到它。在 Python 中修复 ctypes 以便它会找到库是此拉取请求的主题

https://github.com/python/cpython/pull/21241

所以未来版本的 Python 应该可以解决这个问题。

现在要修复它，您可以编辑 PyOpenGL 文件 OpenGL/platform/ctypesloader.py 更改行

    fullName = util.find_library( name )

到

    fullName = '/System/Library/Frameworks/OpenGL.framework/OpenGL'

Answer 2

由于我讨厌修补 Python 包的想法（加上使用 Conda 来安装所述包真的很难管理它），我提供这个 kludge 作为一种解决方法，直到 Python 获得它的 Big Sur（又名 Big Nuisance）更新：

try:
    import OpenGL as ogl
    try:
        import OpenGL.GL   # this fails in <=2020 versions of Python on OS X 11.x
    except ImportError:
        print('Drat, patching for Big Sur')
        from ctypes import util
        orig_util_find_library = util.find_library
        def new_util_find_library( name ):
            res = orig_util_find_library( name )
            if res: return res
            return '/System/Library/Frameworks/'+name+'.framework/'+name
        util.find_library = new_util_find_library
except ImportError:
    pass

Answer 3

最好将其更改为

fullName = "/System/Library/Frameworks/{}.framework/{}".format(name,name)

否则 GLUT 将不起作用。至少，这让我再次运行 Cozmo SDK 的 3d 内容。