I am trying to render a skybox in openGL using the code found here: http://csc.lsu.edu/~kooima/misc/cs594/final/part2.html
However, the "horizon" color moves around, while the halo around the sun stays in place, as illustrated in this picture:
(Ignore the terrain please)
I have copied the code exactly, except replaced the vertex shader code to use more modern openGL. How could i solve this problem?
(So the actual fragment colors are correct relative to the time of day, just the places they are wrong.)