Floor Generation Overview

Floor generation is performed as a list of steps, which allows a developer to customize their floor layout at every part of the pipeline. This page covers the basics of what each step is responsible for and why it is needed.

For information on what steps are required to create a floor from scratch, see Creating Dungeons from Scratch.

Overview

A dungeon map can be generated without items, enemies, or traps. But at a bare minimum, a dungeon map must generate terrain (plus entrance/exit) in order to complete without errors. There are 4 main options on how to do this.

Type	Example	Description	Usage
Grid of Rooms Generation		Rooms generate inside of a grid with cells.	Most dungeon floors
List of Rooms Generation		Rooms generate freely, spreading out from defined halls and rooms.	Uncommon, but used for some dungeon floors
Stairs Floor Generation		Tiles are generated directly on a base of walls.	Rare, primarily debugging
Load Generation	Anything!	Load a pre-made map.	Secret rooms, final floor treasure rooms

To learn more about the technical details of how they generate, visit their pages.

About Steps

Floor generation is broken down into an ordered list of steps, each assigned a priority. The priority determines at what point in the generation process the step should be performed, with a lower number means a step will execute earlier. While these priority numbers do not need to be obeyed for modding, they are the numbers that base PMDO uses.

Priority becomes especially handy when using Zone Steps to plan out dungeon features across multiple floors, rather than a single one.

To view each step that exists and what they do, see Floor Generation Steps.

Priority Brackets

Each range of priority is generally used to perform different tasks. These are each bracket present in PMDO, and what they are generally used for.

Priority	Bracket	Purpose
-7	File Load	Loading a pre-loaded map.
-6	Floor Data	Setting the initial data of a floor.
-5	Grid Creation	Initializing the grid for GridFloorGen.
-4	Grid Path Generation	Generating the initial rooms and halls for GridFloorGen.
-4.1	Grid Special Generation	Generates special rooms outside of the general generation for GridFloorGen.
-3	Room List Creation	Initializing the floorpan for RoomFloorGen.
-2	Room List Generation	Generating the rooms and halls for RoomFloorGen.
-2.1	Vault Pregen	Generation prior to special gen for RoomFloorGen.
-2.2	Room List Special	Generates special rooms for RoomFloorGen.
-2.5	Pre-Vault Clamp	Clamping of the map for vaults.(unverified)
-1	Init Map	Initialize the size of the map.
0	Draw Tiles	Draw tiles to the actual map.
0.1	Unbreakable Layers	Create the unbreakable border around the map borders.
0.2	Floor Extras 1	Add extra floor changes. This is one layer to perform them for priority reasons. Usually has vaults and barriers.
0.3	Floor Extras 2	Add extra floor changes. This is one layer to perform them for priority reasons. Usually has tunnels.
1	Spawn Tables	Defining spawn tables for the floor.
2	Exits	Placement of entrances and exists.
2.1	Save Variables	Things that change depending on save variabes, such as rescues.
2.2	Sealed Detours	Generation for sealed detours.
3	Extra Terrain	The placement of extra terrain types, such as water and tall grass.
3.1	Drop Diagonal	Uses DropDiagonalBlockStep on the extra terrain if needed.
3.2	Erase Isolated	Uses EraseIsolatedStep on the extra terrain if needed.
4	Textures	Assigns textures to the map. At 4 because textures were formerly placed during this step, but are now placed after all steps are done.
4.1	Houses	Placement of houses.
4.2	Shops	Placement of shops.
5	Tile Spawns	Spawning tiles, such as traps.
5.1	Compass Spawns	The spawning of compass tiles specifically.
6	Spawn Money	The spawning of money.
6.1	Spawn Items	The spawning of items.
6.2	Spawn Extra Items	The spawning of additional items with other steps.
6.2	Spawn Mobs	The spawning of mobs.
6.2.1	Spawn Extra Mobs	The spawning of additional mobs outside of the base spawn steps.
7	Debug Checks	Steps that check the dungeon for issues, throwing an error if one is found. Useful for Stress Testing.