Attempt to call an undefined function glutInit

Question

I need a glut window in python. I have the following exception using Python 3.5 and PyOpenGL.GLUT

Traceback (most recent call last):
  File "D:\...\Test.py", line 47, in <module>

    if __name__ == '__main__': main()
  File "D:\...\Test.py", line 9, in main
    glutInit(sys.argv)
  File "C:\...\OpenGL\GLUT\special.py", line 333, in glutInit
    _base_glutInit( ctypes.byref(count), holder )
  File "C:\...\OpenGL\platform\baseplatform.py", line 407, in __call__
    self.__name__, self.__name__,

OpenGL.error.NullFunctionError: Attempt to call an undefined function glutInit,
check for bool(glutInit) before calling

Platform: Windows

Why do i get this error?

Here is my code:

from OpenGL.GLUT import *
import sys

glutInit(sys.argv)

Spittoon

Possible duplicate: #26701219 – Expediency

that question has no answer marked as solution, and the real problem is that the module is not properly reporting missing dll files – Spittoon

and that question is about anaconda and python 2.7 – Spittoon

Answer 1

Problems:

• There was no problem with pip install or easy_install
• The glut.dll and glut32.dll were missing. (They are not part of the PyPI package) you have to install them separately or download it like I did.

Unzipped the dll files from the glutdlls.zip and placed them next to my python file.

Note: You can add the dll files to your PATH variable. Not necessary to keep them next to the py file.

Spittoon

Worked for me.Some clarification for future readers of this: The link to the two needed dlls is: link On Windows 7 put glut.dll and glut32.dll in your Python2.7 OpenGL DLL folder. – Fairspoken

The FTP link is no longer hosted. – Comprador

The FTP link is no longer hosted. – Comprador

Uninstall your current PyOpenGL and simply download PyOpenGL from Unofficial Windows Python Binaries and then install the whl using pip. – Corselet

As @Comprador indicated, the link of @JayJay is not available anymore. From: transmissionzero.co.uk/files/software/development/GLUT/… one can copy the /freeglut-MSVC-3.0.0-2.mp\freeglut\bin\x64/freeglut.dll file into the folder of the .py script you are trying to run. This resolves the error from OpenGL.error.NullFunctionError: Attempt to call an undefined function glutInit to: ctypes.ArgumentError: wrong type at OpenGL\GLUT\special.py", line 73, in glutCreateWindow. Perhaps cause I only found 1/2 .dll files. – Vedda

The 2nd error was for installing "official" PyOpenGL with: conda install -c conda-forge pyopengl which didnt work. Solution I uninstalled the official version with pip uninstall PyOpenGL and installed the Unofficial Windows Binaries as @Corselet suggested. That initially threw errors: .whl is not a supported wheel on this platform. for both the 32 and 64 bit version, but that was because I forgot to select the python 36 version with the name PyOpenGL‑3.1.5‑cp<PYTHON VERSION>‑cp<PYTHON VERSION>m‑win_amd64.whl. Hope this helps someone. Also installed conda install -c conda-forge freeglut. – Vedda

Had to deal with this recently, @MAY's recommendation is what worked for me. installing freeglut from conda-forge was not required in my case, maybe because I already had it somewhere else (vcpkg?) – Casiano

I had to name the glut dll as "site-packages/OpenGL/DLLS/freeglut64.vc9.dll" before it was found. Finding the dll is the job of "OpenGL/platform/ctypesloader.py" and I had to breakpoint inside that file to find out what file name it was seeking. (Am using python 2.7) – Russi

Answer 2

I was being thrown the same error message. I tried installing the DLLs separately and everything and nothing worked. The code that gave me the error was calling the glutInit() function. While I was getting the error, my imports looked like:

import OpenGL
import OpenGL.GL
import OpenGL.GLUT
import OpenGL.GLU

I then changed my imports to:

import OpenGL
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *

and the error was fixed.

Vaucluse

But this is what the OP did. I also did that and the error cries out loud! – Brittneybrittni

Answer 3

I tried some other thing and it worked perfectly. the path Lib/site-packages/OpenGL/GL/DLLS MUST have the dll file. No other thing required. No cmake or Visual C++ as may some sites suggest.

Sharisharia

Another non-working solution. You made me create this folder and store in there the dlls but the error still cries out loud. – Brittneybrittni