Re: [PyOpenGL-Users] BUG (?) Exceptions not working?

[Alejandro S. <as...@gm...>]

Hi Ian,

On Thu, Feb 4, 2010 at 10:03 PM, Ian Mallett <geo...@gm...> wrote:

> Hi,
>
> So I've been trying to debug some code, and it now occurs to me that
> PyOpenGL's method of redirecting OpenGL error flags to the console as
> tracebacks simply isn't working.
>
> Absolute nonsense goes unchallenged:
>
> glClear(GL_BLEND|GL_TEXTURE_2D)
>
> glViewport(0,0,-800,-600)
>
> glBegin(GL_QUADS)
> glClear(GL_DEPTH_BUFFER_BIT)
> glEnd()
>
> etc.
>
> I really REALLY need to be aware of opengl errors to debug various problems
> with framebuffers/shaders/etc.  What's going on?
>
> PyOpenGL 3.0.1b2
>
>
I've noticed that you actually need a valid OpenGL context in order to be
able to detect gl errors. I modified your example slightly and seems to be
throwing errors now:

Negative Viewport dimensions:

>>> import pygame
>>> from OpenGL.GL import *
>>> pygame.init()
(6, 0)
>>> pygame.display.set_mode((100,100), pygame.OPENGL)
<Surface(100x100x32 SW)>
>>> glViewport(0,0,-800,-800)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.5/site-packages/OpenGL/error.py", line 194, in
glCheckError
    baseOperation = baseOperation,
OpenGL.error.GLError: GLError(
err = 1281,
description = 'invalid value',
baseOperation = glViewport,
cArguments = (0, 0, -800, -800)
)
>>> glViewport(0,0,800,800)

Calling glClear between glBegin()...glEnd() block:

>>> glBegin(GL_QUADS)
>>> glClear(GL_DEPTH_BUFFER_BIT)
>>> glEnd()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.5/site-packages/OpenGL/GL/exceptional.py", line 55,
in glEnd
    return simple.glEnd( )
  File "/usr/lib/python2.5/site-packages/OpenGL/error.py", line 194, in
glCheckError
    baseOperation = baseOperation,
OpenGL.error.GLError: GLError(
err = 1282,
description = 'invalid operation',
baseOperation = glEnd,
cArguments = ()
)

Let me know how it goes.

Best regards,
Alejandro.-


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