TESTVERT.WAD
============
TESTVERT is a simple WAD designed to illustrate the behaviour of the DOOM 
gaming engine when dealing with certain vertical displacements.
 
This very simple WAD starts out with the player at the top of a lift-shaft, 
just as depicted in the RMB user manual (see the description of the BLOCK 
option).  If you load DOOM with this WAD and start to move towards the lift 
(visible from the floor pattern), the lift will begin to descend some time 
before you reach it (don't get on it - I didn't include any mechanism for 
getting back up!).  If you listen to it descend, you'll get a feel for how far 
it's gone.  Move forward cautiously and stand right on the edge of the shaft.  
Notice how nothing shows any sign of having seen you (no noises, anyway).  
Switch to map mode and use the cheats (I assume you know what they are) to 
view all of the map and objects.  Notice there are three objects down the 
passage to the west, at the bottom of the shaft.  These are imps, and they're 
facing your way.  Understandably, they don't see you standing at the top of 
the shaft.  Now fire your gun: all three imps wake up and head your way.  I've 
put a monster-blocker in the corridor a little way from the lift to prevent 
them from ever coming into an area where they might conceivably look up the 
shaft and see you (one of them was virtually standing on it before you woke 
them up): you should see them pace up and down between this line and the wall 
at the end of the corridor.  If you're still standing on the edge of the lift 
shaft, it won't be long before the imps decide to take pot shots at you: the 
engine clearly thinks you're visible, despite the vertical displacement of the 
shaft (though not as visible as if you were at the bottom -- the imps only 
fire occasionally) - maybe they can just smell you?  Notice how the missiles 
never get into the lift shaft though: they are hitting the ceiling of the 
corridor below.  If you back off slightly, the imps now aim lower and the 
missiles enter the lift-shaft but explode harmlessly against the wall below.  
How did they know you'd moved?  They can't see you, right?  If you back off a 
bit further, the imps do eventually stop firing at you.  Presumably, you are 
now truly out of sight.  Is this ability of monsters to see through floors and 
ceilings a 'feature' or a 'bug'?  I'll leave it up to you to decide.

With RMB's BLOCK option, you have the power to prevent this particular 
behaviour, if you should so wish.  Use RMB to optimise TESTVERT.WAD using the 
option file TESTVERT.REJ supplied: this applies a BLOCK as described in the 
RMB manual (under the BLOCK option description).  If you play the WAD after 
treatment with RMB, you should find that the imps now don't fire at you until 
you jump down the lift shaft.  Again, it's entirely up to you which mode of 
operation of the game you prefer: you can have both now!

----
(C) Steve Benner Oct 1994.


