This is an effect without shaders I made that simulates blurring with distance. If you have a landscape of your own rather than the demo cube then it would look quite a lot better. I hope you'll find some part of this code useful!
sync on
sync rate 30
rem The length of clear vision
sightlength=400
rem The object that will help make the distance blur
make object plain 1,screen width(),screen height()
rem I'm setting the blur object not to recieve ambient light so that the brightness is the same as the test object below
set object ambient 1,0
rem The camera that will help make the distance blur
make camera 1
rem A test object
make object cube 2,40
rem Positioning and colouring the backdrop of each camera
autocam off
position camera 0,0,40,-200
xrotate camera 0,0
xrotate camera 1,0
color backdrop 0,rgb(0,0,0)
color backdrop 1,rgb(0,0,0)
do
rem Positioning the blur object
position object 1,camera position x(0),camera position y(0),camera position z(0)+sightlength
rem Positioning the blur camera
position camera 1,camera position x(0),camera position y(0),camera position z(0)`+sightlength
rem Setting the blur camera to a low-resolution image to be the blur effect
set camera to image 1,1,screen width()/7,screen height()/7
rem Texturing the blur object with the blur image
texture object 1,1
rem Simple movement of the main camera
if upkey()=1
move camera 0,1
endif
if downkey()=1
move camera 0,-1
endif
sync
loop
sync
PS: You'll have to change the size of the blur object if you change the distance away it is... just a note.
Alpha-mapped plains rule the world.