[PyOpenGL-Devel] [ pyopengl-Bugs-1953886 ] glutCreateMenu ctypes Argument Error

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Bugs item #1953886, was opened at 2008-04-29 01:00
Message generated for change (Comment added) made by mcfletch
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Peter Barth (peterbarth)
Assigned to: Nobody/Anonymous (nobody)
Summary: glutCreateMenu ctypes Argument Error

Initial Comment:
With PyOpenGL-3.0.0-0.3.a6 on fedora 7 using glutCreateMenu gives a ctypes Argument Error.
Similar problems on MacOs, not on Windows.

Traceback (most recent call last):
...
"/usr/lib/python2.5/site-packages/OpenGL/GLUT/special.py", line 165, in glutCreateMenu
    result = simple.glutCreateMenu( cCallback )
ctypes.ArgumentError: argument 1: <type 'exceptions.TypeError'>: expected CFunctionType instance instead of CFunctionType

culprit seems to be in 
--- OpenGL/GLUT/special.py, 159
the definition of the callbackType

    callbackType = FUNCTION_TYPE( ctypes.c_int, ctypes.c_int )

used in glutCreateMenu, which conflicts with
--- OpenGL/raw/GLUT/__init__.py, 118
    argTypes=[FUNCTION_TYPE(None, c_int)],

the conflicting lines appear to be in 3.0.0b1 as well.

Fixing it with a module imported before any other PyOpenGL module
---
# fixme
import ctypes
from OpenGL.raw import GLUT as simple
MENUFUNC = ctypes.CFUNCTYPE(None, ctypes.c_int)
def fixed_glutCreateMenu(menu_func):
    """replacement for broken glutCreateMenu"""
    menu = simple.glutCreateMenu(MENUFUNC(menu_func))
    return menu

# now replace existing version in OpenGL.GLUT
import OpenGL.GLUT
OpenGL.GLUT.glutCreateMenu = fixed_glutCreateMenu
---
seems to work.

----------------------------------------------------------------------

>Comment By: Mike C. Fletcher (mcfletch)
Date: 2008-05-02 10:59

Message:
Logged In: YES 
user_id=34901
Originator: NO

Seems the FreeGLUT header has a different spec than the GLUT header for
the function.  I've updated the type definition manually and it seems to
work properly on a void return system using the int return value.  Also
fixed an error in recording the c-level callback object in context data.

thanks.

----------------------------------------------------------------------

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