Re: [PyOpenGL-Users] glutInitDisplay segfault in python, but works in C++

[Sovannara H. <hak...@gm...>]

Hello,

I ran gdb on the hello.py using Ubuntu 10.04 and intel graphic card
(There was no problem with the same computer in fedora 12.)

(gdb) r
Starting program: /usr/bin/python hello.py
[Thread debugging using libthread_db enabled]

Program received signal SIGSEGV, Segmentation fault.
0x004fb256 in glGetError () from /usr/lib/mesa/libGL.so.1
(gdb) bt
#0  0x004fb256 in glGetError () from /usr/lib/mesa/libGL.so.1
#1  0x0049301f in ffi_call_SYSV ()
   from /usr/lib/python2.6/lib-dynload/_ctypes.so
#2  0x00492e4c in ffi_call () from /usr/lib/python2.6/lib-dynload/_ctypes.so
#3  0x0048d48d in _CallProc () from
/usr/lib/python2.6/lib-dynload/_ctypes.so
#4  0x00484e1e in ?? () from /usr/lib/python2.6/lib-dynload/_ctypes.so
#5  0x0806245a in PyObject_Call ()
#6  0x080e0471 in PyEval_EvalFrameEx ()
#7  0x080e2807 in PyEval_EvalCodeEx ()
#8  0x0816b2ac in ?? ()
#9  0x0806245a in PyObject_Call ()
#10 0x0806a45c in ?? ()
#11 0x08066573 in PyObject_CallFunctionObjArgs ()
#12 0x00484f4a in ?? () from /usr/lib/python2.6/lib-dynload/_ctypes.so
#13 0x0806245a in PyObject_Call ()
#14 0x080e0471 in PyEval_EvalFrameEx ()
#15 0x080e2807 in PyEval_EvalCodeEx ()
#16 0x080e2907 in PyEval_EvalCode ()
#17 0x081005ad in PyRun_FileExFlags ()
#18 0x08100812 in PyRun_SimpleFileExFlags ()
#19 0x0805de5c in Py_Main ()
#20 0x0805d03b in main ()

it seems that the intel driver doesn't handle very well the glGetError()
called by glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB)
because there was no context at this point.

but if we put a glCreateWindow("hello") just before glutInitDisplay
the program doesnt segfault anymore.

Sovannara.

On 23 February 2011 17:22, Alejandro Segovia <as...@gm...> wrote:

> Hello Duong,
>
> On Wed, Feb 23, 2011 at 2:08 PM, Duong Dang <dan...@gm...> wrote:
>
>> On Wed, Feb 23, 2011 at 4:53 PM, Ian Mallett <geo...@gm...>
>> wrote:
>> > On Wed, Feb 23, 2011 at 8:38 AM, Alejandro Segovia <as...@gm...>
>> > wrote:
>> >>
>> >> Hello Duong,
>> >>
>> >> On Wed, Feb 23, 2011 at 11:55 AM, Duong Dang <dan...@gm...>
>> wrote:
>> >>>
>> >>> Hello there,
>> >>>
>> >>> We are having a problem with PyOpenGL on a Ubuntu 10.04 machine with a
>> >>> Intel GMA945 graphics card. The following code works in C++, but its
>> >>> counterpart seg-faults in python. Any idea why that is?
>> >>
>> >> I can't reproduce the problem on an NVIDIA video card,
>> >
>> > Nor I.
>>
>> Thanks for testing, we also tried
>> http://www.opengl.org/resources/code/samples/redbook/hello.c
>> and
>>
>> http://bazaar.launchpad.net/~mcfletch/pyopengl-demo/trunk/annotate/head:/PyOpenGL-Demo/redbook/hello.py
>>
>> which should be identical. The c program displays a white square just
>> fine but the python script seg faults again on the Intel card.
>> On another PC with a nvidia card, both programs work fine.
>>
>
> Do you have any other information on the crash? What OS are you running the
> script on? If you're on Linux, maybe you could record and inspect a valgrind
> dump. I don't know of any equivalent tools for Windows.
>
> Alejandro.-
>
>
> --
> Alejandro Segovia Azapian
> Director, Algorithmia: Visualization & Acceleration
> http://web.algorithmia.net
>