SViewport::FArguments::RenderDirectlyToWindow

Whether or not to render directly to the window's backbuffer or an offscreen render target that is applied to the window later Rendering to an offscreen target is the most common option in the editor where there may be many frames which this viewport's interface may wish to not re-render but use a cached buffer instead Rendering directly to the backbuffer is the most common option in the game where you want to update each frame without the cost of writing to an intermediate target first.