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Title : Keys and Locks Demo
Filename : KeysDemo.zip
Author : David Vrabel
Contact info : dv207@cam.ac.uk
Homepage : NA
Date of release : 15 January 2002
Version : 1.0

Description : Demonstration of the use of keys and locks.

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* Play Information *

Game : Thief II
File names : miss20.mis

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* Loading Information *

Runs from Dark Loader. Leave the file ZIPPED - DO NOT UNZIP this
file, but put the whole "keys.zip" file into whatever
folder/directory you want to on your hard drive, then in Darkloader
setup, point to this folder/directory, and the mission should show up
in the Darkloader main screen.

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* Copyright Information *

Permission is granted to use this mission for any purposes to the
extent permitted by the terms of the Thief 2/DromEd licence.

This level was not made and is not supported by Looking Glass Studios
or Eidos Interactive.

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* Keys and Locks Tutorial *

Every lock is described by a "Region Mask" and a "Lock ID". Keys be
regular keys or master keys. Regular keys open all locks with a
specific region mask and lock id. Master keys open all locks in one
or more regions regardless of lock id.

* Master key or regular key?

Note that you'll only need a master key if you also want regular keys
specific to each door. Otherwise you can just use a regular key and
make all the locks the same.

Master keys are useful for giving to AIs so they can open all the
doors without having to give them multiple keys.

* Choosing regions

If you aren't going to have any master keys you only need one region.

If you want a master key that opens all locks in a level you'll need
only 1 region. If you require a special lock that cannot be opened
with the master key you'll need 2 regions (one for the master key and
one for the special lock). Similarly, for 2 master keys (for example
one for one building and one for another) and a special key (a safe
key for example) you'll need 3 regions.

* Specifying locks

To lock an object (such as a door or container) open the object's
properties and add:

1. Engine Features -> Locked and set it to true.

2. Engine Features -> Key Dst. Leave the master box unchecked as it
has no meaning for locks (only keys). The region mask is a binary
value with only one bit set (1, 10, 100). Use a different binary
value for each region. (I suspect that the maximum number of
regions is 8 though I haven't tested it.)

* Specifying regular keys

Edit the key's properties and add:

1. Engine Features -> Key Src. Leave Master unchecked and enter the
region mask and lock ID of the appropriate lock.

* Specifying master keys.

Edit the key's properties and add:

1. Engine Features -> Key Src. Check the Master box. Enter the bitwise
AND of all the region masks this key is to open. For example if we
want the key to open region 1 and region 10 locks then the region
mask would be 1 AND 10 = 11. Leave the lock ID as 0 as it is not
used for master keys.