How can I use a SDL2 application as a desktop background?
So, with the old SDL I could use SDL_putenv("SDL_WINDOWID=0x****") to make SDL draw everything into another window. The program I was using it in was supposed to be a wallpaper app (I'd run it and then the desktop background changed). I intended to use it as a wallpaper, it would draw into, for example, the xfdesktop in XFCE4, because drawing it into the X11 root window causes graphical garbage when using a compositor for some reason. (xfdesktop displays wallpapers and files on the desktop by default in XFCE)
Now, regardless of the fact that the method of forcing it to draw into another window might be terribly bad, unfortunately I can't use it anymore because SDL_putenv doesn't seem to exist in the new SDL2. But I nevertheless have the feeling that there's a lot about X11 that I don't know yet and that there must be some way to render everything beneath all windows.
And I have another related question: Why am I able to set e.g. xscreensavers and feh as desktop background using xwinwrap but not my SDL application?
The reason why I'm doing this: I'd like to have a slideshow as a desktop background, using fancy fade effects.
Any help would be appreciated.