[Development] Windows, OpenGL ES and large textures

[bunjee at omega.gg]

Greeting Qt enthusiasts and ex-trolls,

I'm building multimedia software on Windows with Qt + libVLC and 
recently switched to the OpenGL ES backend 
(setAttribute(Qt::AA_UseOpenGLES)).
Coming from the Desktop OpenGL I immediately noticed how smooth it was 
at resizing windows, and it felt like the proper way to go.

Unfortunately when playing a 1440p / 60fps video the CPU usage increases 
and the rendering gets slower, like way slower than classic OpenGL.
Is there a flag or some configuration to alter OpenGL ES behavior with 
larger textures that update frequently ?

Maybe I'm doing my texturing "wrongly", you can review my shader for 
blending images here: 
https://github.com/omega-gg/Sky/blob/master/src/SkMedia/src/media/WBackendVlc.cpp#L371

Many thanks,

--
Benjamin Arnaud