Attempt to call an undefined function glutInitDisplayMode, check for bool(glutInitDisplayMode) before calling

[elysiaforme]

Hi, thank you for your repo!

I am currently trying to learn how to use PyOpenGL, and my code is as follows:

import numpy as np
import OpenGL
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
class Demo(object):
    def __init__(self):
        # self.geometry = geometry
        glutInit()  
        glutInitDisplayMode(GLUT_SINGLE | GLUT_RGBA)
        glutInitWindowSize(400, 400)
        glutCreateWindow(b"Hello OpenGL")  
        glutDisplayFunc(self.draw_geometry)  
        self.init_condition()  
        glutMainLoop()

    def init_condition(self):
        glClearColor(1.0, 1.0, 1.0, 1.0)  
        gluOrtho2D(-8.0, 8.0, -8.0, 8.0) 
    def render(self):
        pass
    def draw_geometry(self):
        glClear(GL_COLOR_BUFFER_BIT)
        glColor3f(1.0, 0.0, 0.0)  B
        glBegin(GL_QUADS)
        glVertex2f(-2, 2)
        glVertex2f(-2, 5)
        glVertex2f(-5, 5)
        glVertex2f(-5, 2)
        glEnd()
        glFlush()  
if __name__ == "__main__":
    Demo()

The error message is as follows:

NullFunctionError                         Traceback (most recent call last)
Cell In[14], line 33
     31         glFlush()  
     32 if __name__ == "__main__":
---> 33     Demo()

Cell In[14], line 10, in Demo.__init__(self)
      7 def __init__(self):
      8     # self.geometry = geometry
      9     glutInit()  
---> 10     glutInitDisplayMode(GLUT_SINGLE | GLUT_RGBA)
     11     glutInitWindowSize(400, 400)
     12     glutCreateWindow(b"Hello OpenGL")  

File E:\anaconda\envs\opengl\lib\site-packages\OpenGL\platform\baseplatform.py:423, in _NullFunctionPointer.__call__(self, *args, **named)
    421     pass
    422 else:
--> 423     raise error.NullFunctionError(
    424         """Attempt to call an undefined function %s, check for bool(%s) before calling"""%(
    425             self.__name__, self.__name__,
    426         )
    427     )

NullFunctionError: Attempt to call an undefined function glutInitDisplayMode, check for bool(glutInitDisplayMode) before calling

I followed some tutorials online and downloaded the related complete packages from the website :
https://www.lfd.uci.edu/~gohlke/pythonlibs/#pyopengl.
Unfortunately, this website is now closed.

Currently, the tutorials I’ve found are focused on the function glutInit, but I don’t understand how it differs from the function glutInitDisplayMode.I tried downloading glut and freeglut and placed the corresponding files in the site-packages folder, as shown in the picture:

However, this still did not solve the problem.

I am using:

Python 3.8
PyOpenGL-3.1.6
Windows 11

Could you please help me with this? Thanks!