Current, I am aware that the function to set device orientation is platform dependent. on windows, it is done in the program’s main function generated by template:
// set the design resolution screen size, if you want to use Design Resoulution scaled to current screen, please uncomment next line.
// eglView.setDesignResolutionSize(480, 320);
On iOS, it is done by the function I mentioned in the above message. On Adroid, I have not checked it.