DungeonMaker
How WallCrawlers Work
The main work of the DungeonMaker is done in a loop like this:
while(thereAreCrawlers)
getNextCrawler();
Crawler -> MakeStep;
Most of what makes the dungeons what they are goes on inside of MakeStep.
This is simplified pseudocode for it:
frontFree = LookAhead();
//determine how many rows are free of wall tiles in front of the Crawler
//to a width of (2 * corridorWidth + 1) so we can build a wall through the middle
if(frontFree > corridorWidth + 1)
{//there is room to build wall tiles straight ahead
BuildSomeWallTiles(); //as many as
possible, but no more than stepLength
RepositionCrawlerToFrontOfWall();
if( RollOfDice )
{
TurnCrawlerToLookSideways();
//very complicated conditions here to determine new direction
CreateNewCrawler(); //or several, or none, or ColumnJumper
}
}
else if( RoomToGoSideways() )
TurnCrawlerToLookSideways();
else
DeleteCrawler();
WallCrawler and ColumnJumper are subclasses of Builder, but to make things
simpler I will just describe the WallCrawler class including the Builder members.
There are integer members locX and locY that
give the location in the
grid - a member Forward, which gives the direction the
Crawler is currently
facing (this can be North, South, East, and West) - and a member
Direction which gives the direction
the WallCrawler intends to go. Direction can have
9 values - the directions used by Forward, the intermediate directions
(NE, SE, SW, NW), and a value of zero to indicate that no direction is preferred.
When direction is non-zero, only the two directions adjacent to Direction
are legal values for Forward, plus possibly Direction itself. This implies
that e.g. if Direction points North, then West, North, and East are legal
values for Forward, but if Direction points e.g. Northeast, then only North
and East are legal.
The lifespan of WallCrawlers is governed by members age
and maxAge, which work like this: While age is smaller than 0,
the Crawler is dormant -
when its MakeStep method is called, it does nothing but increment age. When
age >= 0, the Crawler does its work building walls,
and when age > maxAge, it is deleted. While age is used internally to
assign Crawlers to generations, maxAge is an important design parameter.
The type of dungeon that is built is strongly influenced by member
stepLength, which gives the maximum number of wall
tiles this Crawler can lay down in one step. This also determines the
distance between points where the Crawler is given the option to change
direction, and, even
when going straight, the distance between points where it can spawn a baby.
Member corridorWidth determines the minimum width
of the corridors
this Crawler leaves open between the wall tiles it builds and other
pre-existing walls.
Finally there is the member opening
with 3 possible values:
(opening == 0) <==> the Crawler will try and leave no opening
in the wall;
(opening == 1) <==> the Crawler will leave an opening in
the wall at the end
of its run;
(opening == 2) <==> the Crawler leave an opening
at the start of its run, then switch itself to (opening = 0).
The fact that Crawlers with (opening == 0) can build a wall right up to and
adjoining another wall means they must be used with care. If such a Crawler
is placed on the outside wall of the dungeon, it has the potential
to cut off all paths
between the entrance of the dungeon and the exit. They are intended
for situations where a room with doors is placed, and walls are desired
that force the player to go through this room, or they can be started
in the open, often back to back with a Crawler with (opening == 1).
Another problem is this: If many Crawlers are started with (opening == 2),
they will switch to (opening == 0), and two such Crawlers can join up with
each other, creating a room without an opening. I have found that this
is not a problem as long as such Crawlers are rare in the first few generations
(where they might create huge enclosed spaces) and no generation has
more than 50% of them. However, if you randomly place items or monsters
in the dungeon and rely on them being accessible, you must either avoid using
such Crawlers, or test for enclosed rooms and deal with them properly
before placing your items.
