как исправить ошибку [CRITICAL] [App ] Unable to get a Window, abort.?

C:\Users\1>cd C:\kivy
 
C:\kivy>python -m pip install --upgrade pip setuptools virtualenv
Requirement already satisfied: pip in c:\users\1\appdata\local\programs\python\python39\lib\site-packages (21.0.1)
Requirement already satisfied: setuptools in c:\users\1\appdata\local\programs\python\python39\lib\site-packages (53.0.0)
Requirement already satisfied: virtualenv in c:\users\1\appdata\local\programs\python\python39\lib\site-packages (20.4.2)
Requirement already satisfied: distlib<1,>=0.3.1 in c:\users\1\appdata\local\programs\python\python39\lib\site-packages (from virtualenv) (0.3.1)
Requirement already satisfied: appdirs<2,>=1.4.3 in c:\users\1\appdata\local\programs\python\python39\lib\site-packages (from virtualenv) (1.4.4)
Requirement already satisfied: six<2,>=1.9.0 in c:\users\1\appdata\local\programs\python\python39\lib\site-packages (from virtualenv) (1.15.0)
Requirement already satisfied: filelock<4,>=3.0.0 in c:\users\1\appdata\local\programs\python\python39\lib\site-packages (from virtualenv) (3.0.12)
 
C:\kivy>python -m virtualenv kivy_venv
created virtual environment CPython3.9.1.final.0-64 in 13304ms
  creator CPython3Windows(dest=C:\kivy\kivy_venv, clear=False, no_vcs_ignore=False, global=False)
  seeder FromAppData(download=False, pip=bundle, setuptools=bundle, wheel=bundle, via=copy, app_data_dir=C:\Users\1\AppData\Local\pypa\virtualenv)
    added seed packages: pip==21.0.1, setuptools==52.0.0, wheel==0.36.2
  activators BashActivator,BatchActivator,FishActivator,PowerShellActivator,PythonActivator,XonshActivator
 
 
C:\kivy>kivy_venv\Scripts\activate
 
(kivy_venv) C:\kivy>python -m pip install kivy[base] kivy_examples
Collecting kivy[base]
  Using cached Kivy-2.0.0-cp39-cp39-win_amd64.whl (4.1 MB)
Collecting kivy_examples
  Using cached Kivy_examples-2.0.0-py2.py3-none-any.whl (9.2 MB)
Collecting pypiwin32
  Using cached pypiwin32-223-py3-none-any.whl (1.7 kB)
Collecting kivy-deps.sdl2~=0.3.1
  Using cached kivy_deps.sdl2-0.3.1-cp39-cp39-win_amd64.whl (2.5 MB)
Collecting docutils
  Using cached docutils-0.16-py2.py3-none-any.whl (548 kB)
Collecting pygments
  Using cached Pygments-2.8.0-py3-none-any.whl (983 kB)
Collecting kivy-deps.angle~=0.3.0
  Using cached kivy_deps.angle-0.3.0-cp39-cp39-win_amd64.whl (4.7 MB)
Collecting kivy-deps.glew~=0.3.0
  Using cached kivy_deps.glew-0.3.0-cp39-cp39-win_amd64.whl (123 kB)
Collecting Kivy-Garden>=0.1.4
  Using cached Kivy_Garden-0.1.4-py3-none-any.whl
Collecting requests
  Using cached requests-2.25.1-py2.py3-none-any.whl (61 kB)
Collecting pillow
  Using cached Pillow-8.1.0-cp39-cp39-win_amd64.whl (2.2 MB)
Collecting pywin32>=223
  Using cached pywin32-300-cp39-cp39-win_amd64.whl (9.2 MB)
Collecting chardet<5,>=3.0.2
  Using cached chardet-4.0.0-py2.py3-none-any.whl (178 kB)
Collecting urllib3<1.27,>=1.21.1
  Using cached urllib3-1.26.3-py2.py3-none-any.whl (137 kB)
Collecting idna<3,>=2.5
  Using cached idna-2.10-py2.py3-none-any.whl (58 kB)
Collecting certifi>=2017.4.17
  Using cached certifi-2020.12.5-py2.py3-none-any.whl (147 kB)
Installing collected packages: urllib3, idna, chardet, certifi, requests, pywin32, pypiwin32, pygments, Kivy-Garden, kivy-deps.sdl2, kivy-deps.glew, kivy-deps.angle, docutils, pillow, kivy, kivy-examples
Successfully installed Kivy-Garden-0.1.4 certifi-2020.12.5 chardet-4.0.0 docutils-0.16 idna-2.10 kivy-2.0.0 kivy-deps.angle-0.3.0 kivy-deps.glew-0.3.0 kivy-deps.sdl2-0.3.1 kivy-examples-2.0.0 pillow-8.1.0 pygments-2.8.0 pypiwin32-223 pywin32-300 requests-2.25.1 urllib3-1.26.3
 
(kivy_venv) C:\kivy> python kivy_venv\share\kivy-examples\demo\showcase\main.py
 
[INFO   ] [Logger      ] Record log in C:\Users\1\.kivy\logs\kivy_21-02-25_0.txt
[INFO   ] [deps        ] Successfully imported "kivy_deps.angle" 0.3.0
[INFO   ] [deps        ] Successfully imported "kivy_deps.glew" 0.3.0
[INFO   ] [deps        ] Successfully imported "kivy_deps.sdl2" 0.3.1
[INFO   ] [Kivy        ] v2.0.0
[INFO   ] [Kivy        ] Installed at "C:\kivy\kivy_venv\lib\site-packages\kivy\__init__.py"
[INFO   ] [Python      ] v3.9.1 (tags/v3.9.1:1e5d33e, Dec  7 2020, 17:08:21) [MSC v.1927 64 bit (AMD64)]
[INFO   ] [Python      ] Interpreter at "C:\kivy\kivy_venv\Scripts\python.exe"
[INFO   ] [Factory     ] 186 symbols loaded
[INFO   ] [Image       ] Providers: img_tex, img_dds, img_sdl2, img_pil (img_ffpyplayer ignored)
[INFO   ] [Window      ] Provider: sdl2
[INFO   ] [GL          ] Using the "OpenGL" graphics system
[CRITICAL] [Window      ] Unable to find any valuable Window provider. Please enable debug logging (e.g. add -d if running from the command line, or change the log level in the config) and re-run your app to identify potential causes
sdl2 - ValueError: angle_sdl2  is not a recognized GL backend
  File "C:\kivy\kivy_venv\lib\site-packages\kivy\core\__init__.py", line 70, in core_select_lib
    cls = cls()
  File "C:\kivy\kivy_venv\lib\site-packages\kivy\core\window\window_sdl2.py", line 152, in __init__
    super(WindowSDL, self).__init__()
  File "C:\kivy\kivy_venv\lib\site-packages\kivy\core\window\__init__.py", line 982, in __init__
    self.create_window()
  File "C:\kivy\kivy_venv\lib\site-packages\kivy\core\window\window_sdl2.py", line 311, in create_window
    super(WindowSDL, self).create_window()
  File "C:\kivy\kivy_venv\lib\site-packages\kivy\core\window\__init__.py", line 1264, in create_window
    self.initialize_gl()
  File "C:\kivy\kivy_venv\lib\site-packages\kivy\core\window\__init__.py", line 1234, in initialize_gl
    init_gl(allowed=self.gl_backends_allowed,
  File "C:\kivy\kivy_venv\lib\site-packages\kivy\core\gl\__init__.py", line 38, in init_gl
    gl_init_symbols(allowed, ignored)
  File "kivy\graphics\opengl.pyx", line 1556, in kivy.graphics.opengl.gl_init_symbols
  File "kivy\graphics\cgl.pyx", line 97, in kivy.graphics.cgl.cgl_init
 
[CRITICAL] [App         ] Unable to get a Window, abort.
 
(kivy_venv) C:\kivy>