Re: [PyOpenGL-Users] settingOpenGL.ERROR_CHECKING to False has strange consequence on function loading

[rndblnch <rnd...@gm...>]

rndblnch <rndblnch <at> gmail.com> writes:

> ok, i think i have made progress in my understanding of the problem.
> regarding extension loading, there is one place where the
> OpenGL.ERROR_CHECKING flag changes the code path taken, it is in
> OpenGL/extensions.py, line 163: the glGetString call will fail silently on
> OpenGL 3+ if error checking is not enabled, while it will raise an exception
> if error checking is enabled.
> in this later case, the alternate code path provided in the except clause
> will correctly fetch the extensions.
> 
> maybe a fix would be to explicitly check for error after the glGetString call?

looks like this was it, the following patch fixes the problem for me:

=== modified file 'OpenGL/extensions.py'
--- OpenGL/extensions.py	2014-01-30 20:32:21 +0000
+++ OpenGL/extensions.py	2014-02-21 15:21:36 +0000
@@ -156,11 +156,13 @@
         if not platform.PLATFORM.CurrentContextIsValid():
             return False
         from OpenGL.raw.GL._types import GLint
-        from OpenGL.raw.GL.VERSION.GL_1_1 import glGetString 
+        from OpenGL.raw.GL.VERSION.GL_1_1 import glGetString, glGetError
         from OpenGL.raw.GL.VERSION.GL_1_1 import GL_EXTENSIONS
         from OpenGL import error
         try:
             extensions = glGetString( GL_EXTENSIONS )
+            if glGetError():
+                raise error.GLError()
             if extensions:
                 extensions = extensions.split()
             else:


renaud