I tried to use this below but it only seems to work with multi texture mode not glsl. Is there any alternates guys? I was going to try to use this for going underwater.
bge.render.setMistStart(start)Sets the mist start value. Objects further away than start will have mist applied to them.
bge.render.setMistEnd(end)Sets the mist end value. Objects further away from this will be coloured solid with the colour set by setMistColor().