[Development] OpenGL Support in Qt5

[Fredrik Höglund]

On Monday 16 July 2012, Thiago Macieira wrote:
> On segunda-feira, 16 de julho de 2012 07.47.10, gunnar.sletta at nokia.com wrote:
> > I both like and dislike the idea. Like because it resolves all the functions
> > and that way save a lot of pain and dislike because it adds a lot of
> > symbols, and I'm a little bit uncertain on the usecase. 
> > 
> > Because the functions are not a well defined subclass hierarchy (and nor can
> > they be), the user will have to make a compile-time decision about which
> > version to code against, making the code less flexible at runtime. Will
> > this be a problem? 
> 
> Let me ask this. How will Qt 5 work under this scenario:
> 
>  - QtGui compiled on a regular Linux box, such as current Fedora, Ubuntu, 
> openSUSE, etc.
>  - Wayland plugin
> 
> The best Wayland plugin's GL integration is "wayland_egl", which requires:
>     contains(QT_CONFIG, opengles2)
> 
> Do we conclude that Qt 5 should use EGL & OpenGL ES 2 for everything, 
> recommend it for everyone, even on desktop systems?

The platform interface API and the rendering API's are orthogonal.

It is possible to use the full OpenGL API with EGL, and to use OpenGL ES 2
with GLX. The OpenGL implementation might not support all API's however.

For example the NVIDIA driver supports OpenGL and OpenGL ES 2 with GLX,
but doesn't support EGL. The Tegra driver supports EGL and OpenGL ES 2,
but doesn't support the full OpenGL API.

At any rate, it certainly is possible to use the full OpenGL API with
wayland, and the wayland gears demo does that.

Fredrik