[PyQt] Invalid Framebuffer operation in PyQt programs

[Arne Schmitz]

Hi everybody!

Since being on Lion, I have problems with my C++ Qt and PyQt OpenGL applications. In basically every PyQt script that uses QGLWidget, I get this error:

PyQt-mac-gpl-4.8.5/examples/opengl $ ./hellogl.py 
Traceback (most recent call last):
  File "./hellogl.py", line 154, in paintGL
    GL.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT)
  File "errorchecker.pyx", line 50, in OpenGL_accelerate.errorchecker._ErrorChecker.glCheckError (src/errorchecker.c:574)
OpenGL.error.GLError: GLError(
	err = 1286,
	description = 'invalid framebuffer operation',
	baseOperation = glClear,
	cArguments = (16640,)
)

This example is the hellogl example from the PyQt distribution. It seems that the QGLWidget gets a paintGL event even when the framebuffer is not yet complete. The same happens with some of my more complex C++ Qt applications, which indicates that this might rather be a Qt problem. Did anyone else notice this, and is there a fix / workaround? Problem is, that it might lead to lots of problems further down the road, since some of my programs rely on the first GL command actually working correctly.

Cheers,

Arne

-- 
Dipl.-Inform. Arne Schmitz              Phone   +49 (0)241 80-21817
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RWTH Aachen University                  Fax     +49 (0)241 80-22899
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