<sunlight>
 <comments>
 The global parameters of sunlight are:
 material -- description of the material used to draw the disc and flares
   colormap -- name of color map asset
   opacitymap -- name of opacity map asset
 xslicenum, yslicenum -- how many slices the material is cut into (2x2, say)
 The sun disc and flares are made up of these slices; each slice can be 
 used more than once. There is a line drawn from the center of the sun, 
 through the center of the screen, to the opposite end of the screen; this 
 line is parameterized so that value "1" means "at the sun center", "0" 
 means "at screen center" and "-1" means "at opposite end". Thus, "0.5" 
 means half-way between the sun center and the screen center.
 Each element has the following parameters:
   size -- greater than 0 and smaller than 0.5, where 1.0 would cover the 
           entirescreen
   slice -- which slice out of the texture to use for this element, where 
            0 means top-left, 1 means top-right, 2 means bottom-left 
            and 3 means bottom-right when there's 2x2 slices.
   position -- where along the line from sun through center that the 
               element should be drawn.
   color -- what color to tint the element with (HTML-style)
   sun -- optional element; set to 1 to make it always draw
 Note that the sun disc itself will be an element, drawn at position 1, 
 with the "sun" parameter set at 1 to make it always draw.
 </>
 <material>
  <colormap>terrain/t003sky4a_dcmoonrings.jpg</>
  <opacitymap>terrain/t003sky4b_dcringschroma.jpg</>
  <lit>0</>
 </>
 <xslicenum>2</>
 <yslicenum>2</>
 <element>
  <size>0.2</>
  <slice>2</>
  <position>1</>
  <color>#ffffee</>
  <sun>1</>
 </>

 
</>