Quote Originally Posted by qtoptus View Post
I don't know if the native Qt paint system is accelerated,
There is no single "native" paint system. Qt uses different paint systems on different platforms by default. You can override that with -graphicssystem switch.

or what graphics API it uses.
On Windows graphics operations are done using the so called "raster engine" Qt has (which is very optimized) and then blitted to Windows surfaces using GDI.

How capable is it to render textured polygons in 2D or perform shader effects...etc.
The only acceleration API Qt officially supports is OpenGL (and GLSL for shaders). There used to be a Direct3D backend but it is not maintained anymore and very likely incompatible with the current needs of Qt.

You should be quite ok with the raster engine, in many cases it's much faster than the accelerated GL backend.