[vtkusers] vtkOpenGLClearErrorMacro() never returns

[Marco Sambin]

Great Bill,

thanks for your comments and thank you in advance for the patch.
Best regards,

Marco
 Il 15/apr/2014 14:42 "Bill Lorensen" <bill.lorensen at gmail.com> ha scritto:

> It seems risky to have glGetError in a while loop without a guard to stop
> the loop. According to the open GL Super Bible, the safe way to clear the
> error is:
> GLenum glError;
> unsigned int i = 0;
>   do
>     {
>     glError = glGetError();
>     ++i;
>     }
>   while(i < 6 && glError != GL_NO_ERROR);
>
> I have see some docs that say there can be more  error codes. Certainly,
> some upper bound should be set.
>
> I'll prepare a patch.
>
>
>
>
>
>
> On Tue, Apr 15, 2014 at 5:58 AM, Richard Whitehead <
> richard.whitehead at vivosight.com> wrote:
>
>> Marco,
>> Thanks for the support!  I only get it on one of my computers, where
>> OpenGL is issuing warnings, but then the purpose of this code is to clear
>> warnings...  It simply doesn't work.  Hopefully someone who knows what it's
>> doing could fix it.
>> Thanks again,
>> Richard
>>
>>
>> On 15 April 2014 10:49, Marco Sambin <m.sambin at gmail.com> wrote:
>>
>>> Hi Richard,
>>>
>>> quite a while ago, while I was making experiments with the use of JOGL
>>> with VTK under Windows, I encountered the same issue that you describe.
>>>
>>> Basically, in some cases my application got stuck, and the CPU usage
>>> went up to 25% (I have a quad core processor on my dev PC). I discovered
>>> this was due to a "vtkClearOpenGLErrors()" call in the rendering pipeline,
>>> which was iterating indefinitely in its "while" loop. Not sure what was the
>>> real cause of this, did not have the time to debug in detail. At that time,
>>> I worked around the problem by setting the VTK_REPORT_OPENGL_ERRORS option
>>> to "false" on CMake (which forces the implementation of
>>> vtkClearOpenGLErrors() to be empty). I understand that this may not be a
>>> viable workaround in your case, and I also believe it would be good to
>>> understand the real cause for this infinite loop inside
>>> vtkClearOpenGLErrors().
>>>
>>> But for now, I can only let you know that "you are not alone" ;-)
>>>
>>> Maybe someone else on the list can shed some more light or share some
>>> experience about this issue.
>>>
>>> Best regards,
>>>
>>> Marco
>>>
>>>
>>>
>>> On Mon, Apr 14, 2014 at 1:04 PM, Richard Whitehead <
>>> richard.whitehead at vivosight.com> wrote:
>>>
>>>>
>>>> This new macro was introduced in 6.1.0.  It is getting called when my
>>>> app exits and it sits in an infinite loop.
>>>> The documentation say is t is supposed to silently clear errors, but it
>>>> is not doing this.
>>>>
>>>> Please can anyone suggest how to fix it?  Since my app is closing I am
>>>> willing to discard errors, but the only method I can see that should clear
>>>> errors is, well, vtkOpenGLClearErrorMacro...
>>>>
>>>> Many thanks,
>>>>
>>>> Richard
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> Richard Whitehead *-* Senior Imaging Engineer
>>>>
>>>> *Michelson Diagnostics Ltd*
>>>>
>>>> *M:* +44 (0)7905 955276   *T:* +44 (0)20 8308 1695
>>>>
>>>> *E: *richard.whitehead at vivosight.com   *W:* www.vivosight.com
>>>>
>>>>
>>>> <http://www.vivosight.com/>
>>>>
>>>>
>>>> Michelson Diagnostics Ltd, 1 Grays Farm Production Village, Grays Farm
>>>> Road, Orpington, Kent  BR5 3BD, UK
>>>>
>>>> Registered Office: 3 Shearwater, Maidstone, ME16 0DW.     Registered in
>>>> England No. 5732681
>>>>
>>>> _______________________________________________
>>>> Powered by www.kitware.com
>>>>
>>>> Visit other Kitware open-source projects at
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>>>> Please keep messages on-topic and check the VTK FAQ at:
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>>>>
>>>
>>
>>
>> --
>>
>> Richard Whitehead *-* Senior Imaging Engineer
>>
>> *Michelson Diagnostics Ltd*
>>
>> *M:* +44 (0)7905 955276   *T:* +44 (0)20 8308 1695
>>
>> *E: *richard.whitehead at vivosight.com   *W:* www.vivosight.com
>>
>>
>> <http://www.vivosight.com/>
>>
>>
>> Michelson Diagnostics Ltd, 1 Grays Farm Production Village, Grays Farm
>> Road, Orpington, Kent  BR5 3BD, UK
>>
>> Registered Office: 3 Shearwater, Maidstone, ME16 0DW.     Registered in
>> England No. 5732681
>>
>> _______________________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>>
>> Please keep messages on-topic and check the VTK FAQ at:
>> http://www.vtk.org/Wiki/VTK_FAQ
>>
>> Follow this link to subscribe/unsubscribe:
>> http://www.vtk.org/mailman/listinfo/vtkusers
>>
>>
>
>
> --
> Unpaid intern in BillsBasement at noware dot com
>
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