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                 *** Tempest's BUILD Tutorial ***
                     Lesson 7 : Making water
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Purpose:
   A Tutorial on making water in Duke Nukem 3D using Build. This time,
   due to the nature of creating water, my example map isn't as 
   visually informative as my previous tutorials. Sorry about that.

Step 1:
   Ok, a waterpool is made out of 2 separate sectors. One above water,
   and one underwater. So, construct a sector that's gonna be your
   pool, seen from above. Assign the water texture (sprite #336) on the 
   floor and you'll see animated water in Build.

Step 2:
   Make the sector that is going to be underwater. This sector MUST be
   the SAME SIZE as the sector above water. With size I mean the width
   and the length, and NOT the height between floor and ceiling. You can
   have different heights.

Step 3:
   Now assign a Lo-tag value of 1 to the above-water sector. (If you have
   forgotten how to assign a lo-tag value to a sector, here's how to do it:
   In 2D-mode point the mouse cursor on a sector and then press 'T'). The 
   underwater sector must have a lo-tag value of 2.

Step 4:
   Now add a sector effector (sprite #1) in the above-water sector and
   another sector effector in the underwater sector. (To add a sector
   effector, point at the floor, and press 'S'. Press V twice to get
   a list of sprites, then select sprite #1). This is important:
   MAKE SURE YOU PLACE BOTH SECTOR EFFECTORS IN THE EXACT RELATIVE
   POSITION TO THEIR APPROPRIATE SECTOR! That is, if one sector effector
   is located in the middle of its sector, then the other sector
   effector MUST also be in the middle of its sector. If you don't do
   this correctly, then you will die whenever you jump into the pool
   from certain places.

Step 5: 
   Assign to both sector effectors a lo-tag value of 7 (2D-mode: point
   at the sprite and press 'Alt-T'). Also assign a hi-tag value ('Alt-H').
   This value most be the same for both sector effectors, and the value 
   must not be equal to the hi-tag values of other sector effectors that
   are used elsewhere in the level. In the example map you'll see that
   I've chosen a value of 100.  
   
Well, there you have it! Basically, water pools work this way: the
game looks if the player is on a sector with a lo-tag=1. It recognizes
this sector as being above-water. It look at the sector effector in
the sector. If this SE has a Lo-tag of 7, the game will transport the
player to a sector with a Lo-tag of 2 (underwater) and a SE with an
equal Hi-tag value. Or something like that.. :-)

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 Cho Yan Wong (aka Tempest)
 pwong@pobox.leidenuniv.nl
 http://www.wi.leidenuniv.nl/~cwong/myindex.html 
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