  Colormaps (used with linedef 242) can now be
  defined using a special name type.  This
  saves having to create raw textures.

  Characters forming the name will be treated
  as hex values.  In the first instance R3D
  will search the names (if any) defined as
  colormaps between the C_START and C_END
  markers to see if there's a match.  If
  there is no match it will then check that all
  eight characters are present and are valid hex
  numbers. If so it will be treated as a filter
  definition.

  To do this the name should be entered in the
  form "AARRGGBB" where

  AA = the alpha value - range 00 - FF (hex)
  RR = the red   value - range 00 - FF (hex)
  GG = the green value - range 00 - FF (hex)
  BB = the blue  value - range 00 - FF (hex)

  Alpha sets the degree of opacity - so 00 is
  not particularly useful!  A value of 80(hex)
  is usually best.

  A default underwater filter which adds a
  greenish tinge, "WATERMAP", is recognised
  by R3D and takes the value 80004FA5 (hex).
  So for underwater sectors using blue water
  flats then this name can just be used to
  set a filter. 

  This gives an opacity of 80H = 128 decimal
  A red   setting of 00H = (none)
  A green setting of 4FH =  79 decimal
  A blue  setting of A5H = 165 decimal

  Thus the same result would be achieved whether
  using the name "WATERMAP" in the editor for
  the texture name or "80004FA5".

  Filters can be set for any of the three defined
  heights in a faked sector (which is why they
  must only be used with a linedef having a 242
  special) and the texture position used -
  top, mid, or bottom or any combination - will
  determine which faked sector gets filtered
  and by what.  It is usually only used with
  the bottom texture to give an underwater
  effect.

  ================================================
  What's a HEX number?

  HEX numbers have a base of 16 and to accomodate
  this use a number range from 0 - F.  This means
  a single digit can be 0 - 9 or A,B,C,D,E or F.

  A is equivalent to decimal 10, B to 11 and so
  on to F which is 15.

  This convention is used as alpha and colour
  values range from 0 - 255 decimal, so in
  order to define all the values in an 8 char
  name (which is the maximum name length allowed
  by the DOOM engine and thus, for compatibility
  reasons, by R3D) hex values are used.  To
  convert to hex you can use the win calculator
  or just divide by 16 to get the high value
  and convert the remainder for the low value.

  E.g. if you want a value of 185(decimal) then;

  185/16 = 11 remainder 9

  Thus, in hex, this translates to B9
  ================================================
