What are the differences of these Qt installations
Under latest Qt 5.2 library category there are:
Qt 5.2.0 for Windows 64-bit (VS 2012, OpenGL, 589 MB ) and Qt 5.2.0 for Windows 64-bit (VS 2012, 590 MB)
I want to know exact different of these installers please help ! do they have especial purposes?
One uses OpenGL directly (the one with OpenGL in the name) and requires you to have OpenGL drivers available. This option will use the best OpenGL version that is available on your platform (including, AFAIK, OpenGL 4).
The second one uses ANGLE project, which translates Qt's OpenGL calls into DirectX calls - so it requires DirectX drivers, but does not require OpenGL to be available on your platform. ANGLE only supports OpenGL ES 2.