[Interest] OpenGL weirdness

[Agocs Laszlo]

Hello,

Yes, check the profile too. Additionally, starting from 5.3, we have a useful example in qtbase/examples/opengl/contextinfo that can be used to check what kind of context is returned for a given version, profile and options combination.

   Gl_Widget glw;
   glw.show();

Here you are asking for OpenGL 2.0. You get a 4.4 compatibility profile context. This is just fine. The driver is free to give you 2.0, 2.1, or a compatibility profile of 3.2, 3.3, 4.x.

   fmt.setVersion(4, 4);
   fmt.setProfile(QGLFormat::CoreProfile);

Here you are asking for 4.4 core profile and that's exactly what you are getting. Are the app's OpenGL shaders and calls prepared to handle core profile?

   fmt.setVersion(3, 3);
   fmt.setProfile(QGLFormat::CoreProfile);

Similarly to the previous, you get 3.3 core.

   fmt.setVersion(2, 1);

Again, it gives you 4.4 compatibility.

   fmt.setProfile(QGLFormat::CoreProfile);

This is again 4.4 compatibility (not core) since you are requesting 2.0 core which does not make sense so the profile is ignored.

Best regards,
Laszlo

________________________________________
From: interest-bounces+laszlo.agocs=digia.com at qt-project.org [interest-bounces+laszlo.agocs=digia.com at qt-project.org] on behalf of Giuseppe D'Angelo [giuseppe.dangelo at kdab.com]
Sent: Thursday, July 24, 2014 2:49 PM
To: interest at qt-project.org
Subject: Re: [Interest] OpenGL weirdness

Hello,

Il 24/07/2014 14:13, Yves Bailly ha scritto:
> Any idea about what's going on? The same thing occures on both MinGW (32bits) and
> Visual C++ 2012 (64bits).

Can you also dump the context profile? Maybe unless you're requesting
both a version >= 3.2 *and* a Core profile, then you're getting a
Compatibility profile.

Regards,
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