About PyOpenGL

[truelixin at gmail.com]

I follow the <OpenGL Programming Guide>, write a small test:

#!/usr/bin/env python
# encoding=utf-8

import sys
from OpenGL.GL import *
from OpenGL.GLUT import *

def display():
    glClear(GL_COLOR_BUFFER_BIT)
    glColor(1.0, 1.0, 1.0)
    glBegin(GL_POLYGON)
    glVertex(0.25, 0.25, 0.0)
    glVertex(0.75, 0.25, 0.0)
    glVertex(0.75, 0.75, 0.0)
    glVertex(0.25, 0.75, 0.0)
    glEnd()
    glFlush()

def init():
    glClearColor(0.0, 0.0, 0.0, 0.0)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0)

def main():
    glutInit(sys.argv)
    glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB)
    glutInitWindowSize(250, 250)
    glutInitWindowPosition(100, 100)
    glutCreateWindow('hello')
    init()
    glutDisplayFunc(display)
    glutMainLoop()

if __name__ == '__main__':
    main()

But I got an error:

Traceback (most recent call last):
  File "test.py", line 36, in <module>
    main()
  File "test.py", line 26, in main
    glutInit(sys.argv)
  File "c:\python25\lib\site-packages\PyOpenGL-3.0.0b8-py2.5-win32.egg
\OpenGL\GLUT\special.py", line 316, in glutInit
    _base_glutInit( ctypes.byref(count), holder )
  File "c:\python25\lib\site-packages\PyOpenGL-3.0.0b8-py2.5-win32.egg
\OpenGL\GLUT\special.py", line 57, in _base_glutInit
    return __glutInitWithExit(pargc, argv, _exitfunc)
  File "c:\python25\lib\site-packages\PyOpenGL-3.0.0b8-py2.5-win32.egg
\OpenGL\platform\baseplatform.py", line 280, in __call__
    self.__name__, self.__name__,
OpenGL.error.NullFunctionError: Attempt to call an undefined function
__glutInitWithExit, check for bool(__glutInitWithExit) before calling

Can anyone please tell me why?