How I can use CS_DROPSHADOW in QT MainWindow

[gaddlord]

I have the following Delphi code:

procedure TfrmSplash.CreateParams(var Params: TCreateParams);
const
CS_DROPSHADOW = $00020000;
begin
inherited;
Params.WindowClass.Style := Params.WindowClass.Style or CS_DROPSHADOW;
end;

What is does is to allow a shadow to be displayed around the splash screen of mine.

How I can hook to CreateParams in QT's MainWindow? Thank you.