Transparent Backgrounds with SDL2 + Wayland

Hey everyone,

Does anyone know if its currently possible to run a non-fullscreen window with a transparent background so that it acts like an overlay in Wayland?

    SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_BLEND);
    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0);
    SDL_RenderFillRect(renderer, NULL);

No matter what, I get a black background (all other drawing functions work normally), and I’ve even tried exporting the hint to enable EGL transparency: export SDL_VIDEO_EGL_ALLOW_TRANSPARENCY=1

The target is an Allwinner H3/Mali 400 with Wayland/Weston. I know Weston’s desktop shell doesn’t support full screen transparency, so I’m trying with a non-fullscreen window.