I hope I'm not being annoying, but as I was browsing through the documentation for SFML 2.4, I found a reference to setParameter in the Shader tutorial. That function was deprecated in that version. Also, there is no reference to geometry shaders, which were added in 2.4. This is just to say that it's not exactly up to date.
This is literally my first post here, so if I'm doing anything wrong (wrong forum, we don't talk about that, etc.), please tell me. Thank you for your time.