Which OpenGL ES version is required by Embedded Qt5 ?

ermitz

If I read there :
http://qt-project.org/doc/qt-5/windowsce-opengl.html#using-opengl-to-accelerate-normal-2d-painting

everything seems nice, Qt is able to support any version of OpenGL ES 1.x or 2.0. There are two subclasses of QPainter. It is not clear if choice is done at Qt configuration time at development time, but it seems clear that we have choice.
However, If I follow Qt OpenGL and then Qt GUI links, it seems that OpenGL 1.x is not supported

If I read there :
http://qt-project.org/doc/qt-5/embedded-linux.html#configuring-for-a-specific-device
it also seems that only OpenGL 2.0 is supported.

Is it possible to get a clearer view ?

Thanks
Eric

SGaist

HI and welcome to devnet,

I would recommend that you ask this question on the interest mailing list. You'll find there Qt's developers/maintainers (this forum is more user oriented)

jeremy_k

It depends on what you want to use. Quick 2 requires ES 2 at a minimum.

As noted in the embedded Linux page, it's possible to do without OpenGL entirely, for example with the LinuxFB QPA plugin.

agocs

Both on desktop and mobile/embedded, prefer using at least OpenGL 2.0 or OpenGL ES 2.0, respectively.

While it is possible to create OpenGL 1.x and OpenGL ES 1.1 applications where you do all the drawing yourself via direct OpenGL calls, much of the related functionality in Qt will not be available or will misbehave. (for example there is no OpenGL 1.x backend for QPainter and Qt Quick 2 is out of question completely)

jeremy_k

@agocs: I think that's a bit unfair to the raster paint engine. Many people are happy with it and widgets.

Yes, it helps a lot to have an ES 2+ capable host. No, abandoning all hope otherwise isn't called for. Be aware that the Qt stack can't help as much when investing heavily on the GPU side of a GPU+CPU system if the OpenGL requirements aren't met.

agocs

Sure, but since we are talking about accelerated painting via QPainter, I have not considered that as an option. Of course, it will work in all cases, regardless of the GPU or OpenGL version.