The simplest solution to do this is writing the antialiasing shader and apply it on sf::Sprite, which uses sf::RenderTexture as its texture. Of course, if your rendering is simple and you render directly to the window, then you can set the antialising in context settings. To summarize, there is no way to apply default OpenGL antialising to any sf::RenderTarget(sf::Window and classes, which derive from or, are exceptions)
