Re: No valid context

--===============7135657991727133061==
Content-Type: multipart/alternative; boundary="000000000000a6898505a3d58348"

--000000000000a6898505a3d58348
Content-Type: text/plain; charset="UTF-8"

On Sun, Apr 19, 2020 at 8:20 AM physkets via PyOpenGL-Users <
[email protected]> wrote:

> Hi!
>
> I'm trying to use pyGLFW to make a simple coloured quad, but I fail with
> the following error message:
>
> Traceback (most recent call last):  File "first.py", line 121, in
> <module>    gl.glVertexAttribPointer(LOCATION, 2, gl.GL_FLOAT, False,
> STRIDE, OFFSET)  File
> "/usr/lib/python3.8/site-packages/OpenGL/latebind.py", line 63, in
> __call__    return self.wrapperFunction( self.baseFunction, *args, **named
> )  File "/usr/lib/python3.8/site-packages/OpenGL/GL/VERSION/GL_2_0.py",
> line 469, in glVertexAttribPointer    contextdata.setValue( key, array )
> File "/usr/lib/python3.8/site-packages/OpenGL/contextdata.py", line 58, in
> setValue    context = getContext( context )  File
> "/usr/lib/python3.8/site-packages/OpenGL/contextdata.py", line 40, in
> getContext    raise error.Error(OpenGL.error.Error: Attempt to retrieve
> context when no valid context
> I am attaching the program that gives me that error along with the shaders.
>
> Am I doing something wrong?
>

FWIW I can't reproduce the issue here, although I note that line 121
mentioned in the traceback does not correspond to that line in the attached
code, so I don't know if the difference matters. Anyway, the code works as
I would expect (Win x64 Py3.7.3, PyOpenGL 3.1.5).

Offhand, I am surprised that `glVertexAttribPointer(...)` would be the call
to fail; there are plenty of other GL calls that should have failed
beforehand, if indeed they didn't fail. GLFW creates a context, and it
looks like you're setting it as current. If that code does what it looks
like, correctly, then the error especially wouldn't make sense. I would
suggest to try validating the context, perhaps creating a debug context.

What happens if you just try drawing an empty window without the
problematic setup code? Also, why did you comment the context creation
hints?

Ian

--000000000000a6898505a3d58348
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><div dir=3D"ltr">On Sun, Apr 19, 2020 at 8:20 AM physkets =
via PyOpenGL-Users &lt;<a href=3D"mailto:[email protected]=
et">[email protected]</a>&gt; wrote:<br></div><div class=
=3D"gmail_quote"><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px =
0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi!<br>
<br>
I&#39;m trying to use pyGLFW to make a simple coloured quad, but I fail wit=
h the following error message:<br>
<br>
Traceback (most recent call last):=C2=A0 File &quot;first.py&quot;, line 12=
1, in &lt;module&gt;=C2=A0 =C2=A0 gl.glVertexAttribPointer(LOCATION, 2, gl.=
GL_FLOAT, False, STRIDE, OFFSET)=C2=A0 File &quot;/usr/lib/python3.8/site-p=
ackages/OpenGL/latebind.py&quot;, line 63, in __call__=C2=A0 =C2=A0 return =
self.wrapperFunction( self.baseFunction, *args, **named )=C2=A0 File &quot;=
/usr/lib/python3.8/site-packages/OpenGL/GL/VERSION/GL_2_0.py&quot;, line 46=
9, in glVertexAttribPointer=C2=A0 =C2=A0 contextdata.setValue( key, array )=
=C2=A0 File &quot;/usr/lib/python3.8/site-packages/OpenGL/contextdata.py&qu=
ot;, line 58, in setValue=C2=A0 =C2=A0 context =3D getContext( context )=C2=
=A0 File &quot;/usr/lib/python3.8/site-packages/OpenGL/contextdata.py&quot;=
, line 40, in getContext=C2=A0 =C2=A0 raise error.Error(OpenGL.error.Error:=
 Attempt to retrieve context when no valid context<br>
I am attaching the program that gives me that error along with the shaders.=
<br>
<br>
Am I doing something wrong?<br></blockquote><div><br></div><div>FWIW I can&=
#39;t reproduce the issue here, although I note that line 121 mentioned in =
the traceback does not correspond to that line in the attached code, so I d=
on&#39;t know if the difference matters. Anyway, the code works as I would =
expect (Win x64 Py3.7.3, PyOpenGL 3.1.5).</div><div><br></div><div>Offhand,=
 I am surprised that `glVertexAttribPointer(...)` would be the call to fail=
; there are plenty of other GL calls that should have failed beforehand, if=
 indeed they didn&#39;t fail. GLFW creates a context, and it looks like you=
&#39;re setting it as current. If that code does what it looks like, correc=
tly, then the error especially wouldn&#39;t make sense. I would suggest to =
try validating the context, perhaps creating a debug context.</div><div><br=
></div><div>What happens if you just try drawing an empty window without th=
e problematic setup code? Also, why did you comment the context creation hi=
nts?<br></div><div><br></div><div>Ian<br></div></div></div>

--000000000000a6898505a3d58348--


--===============7135657991727133061==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline


--===============7135657991727133061==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

_______________________________________________
PyOpenGL Homepage
http://pyopengl.sourceforge.net
_______________________________________________
PyOpenGL-Users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/pyopengl-users

--===============7135657991727133061==--