Does Qt4.6 and later version only support openGL2 to do openGL rendering?

whoknows · wrote on 19 Sept 2010, 09:22

is that true? I find there is a check in a project to check painter engine if qt version is larger than 4.6.

tobias.hunger · wrote on 19 Sept 2010, 16:22

I have never checked the specifics requirements on OpenGL versions in Qt, but the OpenGL 2.0 specification is from 2004... After 6 years a project should be allowed to depend on it, shouldn't it?

whoknows · wrote on 20 Sept 2010, 01:29

yes, of course it could be.

but does Qt 4.6 or later support to use openGL1.x to do rendering?

yan_ · wrote on 20 Sept 2010, 07:31

Hi.

Opengl version is defined by your 3D card drivers not by Qt. You can use all OpenGl version with Qt.

You can use OpenGl 1.x function with higher OpenGl Version. Normally OpenGl version are retro-compatible.

What is your problem?

jorj · wrote on 20 Sept 2010, 08:46

qt definately uses shaders a lot to render with opengl... not sure if it depends on them...

przemo_li · wrote on 13 Dec 2010, 11:00

Yes, by default you will get only 1.1 !!

But if you will provide 2.1 declarations Qt will accept it. (so it is only including headers to get 2.1)

Docs states that You can also get any version supported by graphic drivers by QGLFormat::setVersion() and QGLFormat::setProfile(). But there is not a single doc covering e.g. how to get tessel shaders into QGLShader, etc.
So it should be posibble to run higher than 2.1 but you will have to provide some classes for your self.

And You can freely use OpenGL ES 2.0!! (And if you want to cross-develop on mobile and desktop it is best option, and Qt is ready for it).

[quote author="Tobias Hunger" date="1284913349"]I have never checked the specifics requirements on OpenGL versions in Qt, but the OpenGL 2.0 specification is from 2004... After 6 years a project should be allowed to depend on it, shouldn't it?[/quote]
No it is not!
You have to have hardware (easily meat), but also drivers (unlikely but possible problems), and have to manage extensions (MS still do not support easy 2.1 context creation).

And for newer specifications (we have 3.3 and 4.1 !!!!) even more problems arise like lack of true cross platform support (4.x only on linux and win 3.x troublesome on mac).

And sad but true Nokia and qt team do not look too excited about newest OpenGL specs either.