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How to make levels for Dungeon Crawl Stone Soup
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Part I:    INTRODUCTION
           ============

Contents:  A. Introduction
           B. Sample map
           C. The .des files
           D. Kinds of vaults
           E. Hints for level makers
           F. Principles of vault making
           G. How vaults are picked

This document explains some basics of vault making. For actual vault work,
you will need to look at syntax.txt. However, by simply looking at the
example provided here and looking through arrival.des, you should be able
to make changes or small vaults on your own.


A.   Introduction
=================

A game like Crawl generally uses random content. This also applies to maps,
which are made in various ways, but all with a large random component.
However, for several reasons, it is also useful to have handmade maps: they
can provide challenges random levels would rarely come up with; they can be
especially thematic, for example on branch ends. Simple pre-made pieces of
maps are called "vaults", these can provide challenge, loot, flavour or
just make the rather big levels of Crawl more interesting.

These vaults come in all sizes, from mere 3x3 to level encompassing maps.
Section B contains an example vault (not to be used somewhere), giving you
an idea of how vaults are defined.

Since predefined and fixed content clashes with the philosophy of randomly
generated content, vaults can be randomised in many ways. The other way to
help lessen the effect of deja vu is by having lots of vaults. Therefore,
new vaults are always appreciated.


B.   Sample Map
===============

Before going into the technical details of the level-file syntax, it might be
a good idea to look at an example - a branch entry for the Ecumenical Temple -
to see what a map definition looks like.

# name below:
NAME:    useless_temple_entry
# header section below:
ORIENT:  float                    # "ORIENT: float" tells the level builder that
                                  #     this entry can be anywhere on the level.
TAGS:    temple_entry             #  "TAGS: temple_entry" turns the 'O' on the
MONS:    butterfly, plant         #               map into stairs to the Temple.
ITEM:    stone
KFEAT:   O = enter_temple
# actual map below:               # The symbols on the map:
MAP                               # x - rock wall
xx.d.xx                           # . - floor
x..1..x                           # @ - entry point (
@d2O2d.                           # O - stairs to the Temple
x..1..x                           # 1 - first monster from list (here butterfly)
xx.d.xx                           # 2 - second monster from list (here plant)
ENDMAP                            # d - first item from the list (here stones)

Every map consists of a name, a header and the actual map (the order is not
important as long as the name comes first, but try to stick to this order for
consistency).

Lines starting with # are comments. The keywords available are explained
in detail in the syntax.txt file.


C.   The .des files
===================

All fixed level information resides in various .des files to be found inside
folders of the dat/des directory. If you are interested in adding some vaults,
say, start with the existing ones and modify them. If you are new to vault
making, look at the following files:

  dat/des/arrival
    simple.des - particularly simple arrival vaults; they are ordered with
                 learning the map syntax in mind (all games use a premade
                 map like these for the vicinity of the entrance)

  dat/des/variable
    float.des - floating vaults
    large_abstract.des - all regular vaults which have
    large_themed.des   - ORIENT:encompass/northwest etc
    mini.des  - minivaults (no ORIENT line at all)

There are also the following other directories:

  dat/des/branches - contains vaults for specific branches
  dat/des/portals  - contains all maps and lua for portal vaults
  dat/des/builder  - uniques.des etc.; look, don't touch

If you feel comfortable with vault making in general, you may want to turn to
branch ends or even portal vaults. Poke into the relevant files to get an
impression, or to find examples of how lua is applied.


D.   Kinds of Vaults
====================

The different kinds of vaults used by Crawl are described below.

Arrival vault:
    A map designed for D:1, which (usually) contains the primary upstair {
and is always tagged "arrival". A player starting a new game will usually
land in an entry vault.

Branch entry vault, or branch portal vault:
    A map containing the entry to a branch - either a branch stair (such as
the stair to the Orcish Mines), or a branch portal (a portal to Hell, say).
Always tagged "<branchname>_entry".

Special level:
    A map for a location of significance in the game, such as the Ecumenical
Temple, or the end of branches such as level 5 of the Snake Pit (Snake:5).
Special level maps usually have a PLACE: attribute.

Random vaults:
    Random vaults may be randomly generated at any level in the dungeon.
Random vault maps are selected by the dungeon builder based on their DEPTH:
attributes.

Random minivaults:
    Random minivaults are small maps that are placed onto a level that the
dungeon builder has already constructed fully otherwise (the level may
include other vaults).

Minivaults are distinguished from normal vaults by the absence of an
ORIENT: declaration. Any map without a specified ORIENT: is a
minivault. Minivaults are handled like floating vaults (ORIENT: float
vaults) in most respects. The differences are:

1. Floating vaults may be placed before the rest of the level layout
   is generated, and the rest of the level may be built around the floating
   vault. This is never the case for minivaults.

2. Floating vaults may be placed anywhere in the map, including places
   completely separated from the rest of the level by rock. The
   dungeon builder will then connect the exits from the floating vault
   to the rest of the level, usually producing obvious "passages" from
   the floating vault to the main body of the level.

   In contrast, minivaults are placed such that at least one square of
   the minivault overlaps with an existing part of the level, and are
   thus more likely to look like part of the level.


E.   Hints for level makers
===========================

Stairs
------
You do not have to place all of the stairs unless the level is full
screen, in which case you must place all except the extra stairs (these
are glyphs > and < and produce escape hatches). Any of the other stairs
which are not present in the vault will be randomly placed outside it.

Also generally try to avoid rooms with no exit (you can use > or < to
make it possible for players to get away, although there are other,
more elaborate options like teleportation traps, etc.). However, unless
needed for the purpose, escape hatches are generally not interesting.
If you do use them, > is almost always better than <.

Entry points
------------
The entry point '@' must be present for all vaults (except for
full-screen vaults where it must not, and for floating vaults and
minivaults where it is optional). All @ will be connected to floor
space in the rest of the map (multiple @ close together may merge
into the same exit corridor). Make sure that no part of your entry
level can be cut off! If no @ is present in a floating vault (and
there are no doors on the edge of the map, see below), the level
builder will use one or more random floor spaces '.' or doors at the
circumference as exits. Note that it is not possible to predict
which spaces the level builder will choose to connect; if you need
predictability, use explicit @ exits on the edge.

The level-builder will also implicitly treat doors and runed doors
on the edge of a map as explicit exits (the same as using @) and
connect them to the rest of the level.

Not using @ will cause the level builder to pick exits randomly from
non-solid squaress on the edge of your vault. You should always either
have explicit exits or accessible squares; if the vault is completely
inaccessible (by exits, non-solid squares that can act as exits, or by
stair), it will fail to load - so don't do that.

Minivaults vs. random vaults
----------------------------
Minivaults are handled very differently from regular vaults and special
levels. They're placed *after* normal map generation, whereas normal
vaults are placed before generating the rest of the level. There's no
way to guarantee generation of a minivault on a particular level, although
using a PLACE: attribute makes the dungeon builder try very hard to place
the minivault on the specified level. Regular vaults can always be forced to
appear using a PLACE: attribute.

Technically, you make a minivault like a normal floating vault but
without an ORIENT: line. Note that minivaults used to be exclusively of
size 12x12 but this restriction is gone. Still, the smaller the better.

Where possible, use minivaults instead of regular vaults, because the dungeon
builder has greater freedom with the rest of the level layout when using
minivaults.

levdes.vim
----------
If you use vim, the levdes.vim syntax highlighting script (provided
in the dat directory) can make level-editing far more pleasant by colouring
different features in maps and syntax-highlighting .des-file syntax. vim is
available for nearly all operating systems, including Windows.


F.   Principles of vault making
===============================

Small is good!
--------------

This applies mostly to arrival vaults and minivaults. Especially arrival
vaults should be rather small. Their intention is to provide some
atmosphere for the starting room, not to get a grip on the whole of D:1.
Minivaults should be rather small, as well, in order to increase the chances
they may actually be chosen during level generation.

Randomise!
----------
The level making syntax is very supportive for making a single map appear
in many versions. Use the SHUFFLE: and SUBST: and NSUBST: directives and
look at the existing arrival vaults. Besides reducing tedium, this avoids
giving veterans a spoiled edge. As an example, if a secret chamber with
loot is always at the same place, it's a no-brainer for those who know.
The same goes for traps. This is much less so if there are several places
for the chamber (or trap) and there's even a chance it doesn't exist.

You can also use WEIGHT to create modified versions of the same map. In
order to do this, make several maps and endow each with a chance such
that the sum of chances add up to 10.

Randomisation does not just apply to layout: you could also have
different monster population sets (for example make a branch end skewed
for either melee or ranged opponents), or perhaps couple difficulty to
loot.

Not too much loot!
------------------
For example, arrival vaults should in general have very little loot - in
particular no good_xxx or '*' items lest they might give incentive for
start-scumming. For random vaults, there needn't be loot at all and, in
any case, there shouldn't be too much of it. Compare with the branch ends
rich in treasure (Tomb:3, Cocytus etc.) to get a feeling for this.

It is very easy to fall into the power spiral trap: making newer vaults
harder than the old ones, but handing out more loot. Be strong, don't
give in to that temptation.

Have a theme.
-------------
It is often worthwhile (for me at least) to have a theme in mind before
making the actual level. For arrival vaults, something simple like 'forest'
or 'fortress' may be enough. For later (or larger) maps, try to think of
distinguishing features your map may have. Being cool can be good enough,
but possessing some gameplay value (for example by being easier for
particular skills/capabilities like ranged attacks or Traps & Doors or
necromancy) is even better.

Testing your maps.
------------------
This is easy for arrival vaults. Temporarily introducing either
    WEIGHT: 50000   or
    PLACE:  D:1
will make your entry appear almost always. For other vaults, you can
for the moment declare them as arrival vaults with a huge WEIGHT: as
above (and preferably in wizard mode).

In wizmode, you can use the following commands
    &L "map name"   (creates that vault on the current level)
    &P "map name"   (creates a level with that vault guaranteed to be in it)
    &~              (for jumping to a branch end).
For both &L and &P, you don't need to specify the full name of the vault,
a substring which uniquely determines the vault is enough. If a branch end
has several alternatives, you may want to use a high WEIGHT: again.

Minivaults can also be tested by adding a PLACE: to the definition, which
makes it very likely that the minivault will appear in the chosen level.

If the .des file syntax is incorrect, Crawl will tell you on which line of
which des file it found the syntax error, making for easier debugging.

Be fair!
--------
Crawl is hard but try to balance your monsters. While it is true that Orc:1
can show an orc knight, this is very rare. Hence it's probably a bad idea
to use orc knights for an entry to the Orcish Mines.

Phrased more generally, do not use OOD (out-of-depth) monsters unless you
really know what you want.

Be especially fair when creating arrival vaults. If your vault is too hard,
it might get just trashed. Keep in mind that your vault will be played very
very often, so even small chances of something stupid happening (like
creation of a really nasty monster) will kick in often enough.

Glass, colours, names: use sparingly!
-------------------------------------
It can be very tempting to use the cool new features all over the place:
transparent walls for looking through, colouring walls and floor in exotic
ways, giving monsters special names.
Each of these have their uses, but ask yourself each time if the vaults
really benefits from this. If all vaults use colours, actual flavour has
been lost.


G.   How vaults are picked
==========================

The dungeon builder selects vaults by:

1. PLACE: Before the dungeon builder starts building a level, it looks
   for non-minivaults that are marked for the same PLACE: and places
   them. After building the level, it looks for minivaults that are marked
   for the same PLACE: and attempts to place them.

2. TAGS: Branch entries, Pandemonium special levels, etc. are placed by
   looking for vaults with a particular tag, for instance "mnoleg".

3. DEPTH: When building a level, the dungeon builder looks for random
   vaults that are eligible to be placed in that DEPTH range.

If you do not want a vault to be randomly generated, do not assign it
a DEPTH. If the vault is in a des file with a default-depth set, you
can force it to have no DEPTH setting with an empty DEPTH: line.

Vaults without a DEPTH: should be eligible to be selected in some
other way, either by PLACE: or by tag.
