I've decided to start contributing classes I've made to work with SFML that are clean enough / don't rely on modified SFML / etc. for public release. I'll have others, but the first one is a drawable-derived class for shapes composed of lines. While this same effect can be achieved with multiple sf::Shape primitives, my class is specifically designed for this task and is thus much faster (and I think simpler) making use of both GL_LINES and display lists.
Read the comment on top of the header for quick info on how to make a shape. It's pretty simple. You define vertices and then connect them however you want with line segments. The shapes can then be modified dynamically by adding/removing/moving points and line segments.
It should work fine, but let me know if you encounter any problems.
It's released under the same license as SFML, zlib/png and is located under "sources" in the wiki.
I'll probably be releasing an animated sprite class later. (It works, but isn't ready for public release.)
I also have an extension for SFML to add alpha texture objects that can then be used to make blended/overlayed/shadowed sprites, etc. But I'm not as sure about releasing that since it requires modding SFML and is not quite as "just-drop-it-in" as the others.
@Laurent: This is my first time editing a wiki, so if you end up with a log that said someone did like 10 edits before getting it right... um sorry. :oops:
Edit: Here's a screenshot demo. Both the map border and terrain tile selection boxes are easily done with this class.