OpenGL 2D Independent Resolution Rendering

Around two years ago I made a tutorial for XNA in which you could render 2D games scaled to the current window resolution with proper letter-boxes or pillar-boxes. As many know since then I moved to C++ and OpenGL, and

XNA 2D Independent Resolution Rendering

Note: 22/04/2013 – Due to popular request I made an article about achieving this effect in OpenGL Independent Resolution Rendering?? What’s this all about? Basically a way of not caring what you resolution is. Ever had Gui elements misplaced because