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Generate a zelda 1 like dungeon using Joris Dormans' Mission Graph and Layout Grammar
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Graph Dungeon Generator


This project generates game dungeons similar to the first zelda dungeons with only normal keys (no key items or breakable walls). The code is based on Joris Dormans' work in dungeon generation for Unexplored.


  • generate a graph of mission graph that describe how to solve the level similar to Mark Brown's Graph in Boss Keys series.
  • generate a 2D grid of equal sized rooms for the mission graph similar to the first zelda dungeon layout. The number of generated rooms will be equal to the number of


The project consists of two generators:

  • Mission Graph: generates a graph that consitute the game's mission.
  • Layout Map: lays down the graph on a 2D grid of cells where each cell can be connected from any of the four main directions (North, South, East, and West).

Mission Graph

The Mission Graph consists of 7 different type of nodes that can be found in the enum ObstacleTowerGeneration.MissionGraph.NodeType. Each node represent different game room:

  • Start: is the room where the level starts.
  • End: is the room where the level ends.
  • Key: is a room that has to have a key in it.
  • Lock: is a room that can only be reached through one door that is locked and require a key to open.
  • Lever: is a room that connects rooms from behind a lock room to rooms that are before.
  • Puzzle: is a room that involve a challenge that need to be passed to move on.
  • Normal: is any other room other than the previous ones.

Every node in the Mission Graph have an access level. An access level is a number that determines how many Puzzle and Lock nodes you passed on before reaching that node. For example: a node with access level of 0 means that it is connected to the start node without having any puzzle or lock nodes in between, while a node with access level of 2 means that there is two nodes of type Puzzle or Lock in between the start node and that node. The access level is very helpful in generating the Layout Map and also for generating Lever nodes.

The Mission Graph uses graph grammar to generate the mission. All the grammar is implemented in grammer/ folder. There is 8 different grammar rules:

  • addNormal: adds a Normal node between two nodes of the same level.
  • addPuzzle: adds a Puzzle node between two nodes of the same level which will raise the second node level.
  • addKeyLock: adds a Lock node between two nodes of the same level which will raise the second node access level, then add a Key node as a branch from the first node.
  • addNormalToKey: add a Normal node between two nodes of the same level where the second node is a Key node.
  • addLever: connects a high access level node to a low access level node using a Lever node.
  • makeLink: connects two nodes of the same access level using a normal link.
  • makeBranching: change the structure of three consecutive nodes to make them as branching nodes.
  • moveLockBack: moves a normal task from behind a Lock node towards before which will decrease its access level.

To adjust the generated Mission Graph use the graphRecipe.txt file. The file consists of several lines where the system applies each line in order for 0 to many times. If any line starts with a # the system will consider it as a comment and ignore it. Each line consists of 3 parts separated with commas:

  • Rule Name: is the name of the rule that need to be applied. If the system didn't find that rule defined, it will apply a random rule. You can use that point to apply random rules by writing random in the rule name.
  • Minimum Number: is the minimum number of times the system has to run that rule.
  • Maximum Number: is the maximum number of times the system has to run that rule. For example: addNormal, 0, 3 means the system will apply addNormal rule between 0 and 3 times. At any time, the user can remove one or two of the arguments. For example: addNormal, 3 will apply addNormal 3 times, while addNormal will apply it 1 time.

Layout Map

The layout map is the physical representation of the Mission Graph in 2D space. The layout map consists of 2D grid of ObstacleTowerGeneration.LayoutGrammar.Cell The layout make sure the start node and end node has only one connections while the rest of cells can have up to four connections (North, South, East, and West).

There is two types of cells:

  • Normal: are cells that corresponds to a certain node in the Mission Graph.
  • Connection: are additional cells that were added to facilitate connections in the physical space.

Each cell has from 1 door up to 4 doors. Doors are the connection between cells in the phyiscal space. There is 4 different door types:

  • Open: means that it is a normal opening between these two cells.
  • KeyLock: means that it needs a key to go through it.
  • LeverLock: means it will open using a lever in the nearby lever room.
  • PuzzleLock: means it will open when solving a puzzle in the nearby puzzle room.

How to use the Code

You can generate a dungeon using generateDungeon function in ObstacleTowerGeneration.Program file. The function takes 3 parameters which identify the number of times the system will try to generate the dungeon. Default values are 100 for each of the dungeon pieces and 100 for the total dungeon.

The generateDungeon function returns a DungeonResult struct. The DungeonResult struct consists of 2 parts:

  • missionGraph: is a ObstacleTowerGeneration.MissionGraph.Graph object that represents the generated Mission Graph.
  • layoutMap: is a ObstacleTowerGeneration.LayoutGrammar.Map obejct that represents the generated Layout Map.


Graph object is a list of ObstacleTowerGeneration.MissionGraph.Node objects that consitutes the full graph. Each node has accessLevel, type, and id properties. accessLevel is an int that reflects the value of the access level of the node, type is an enum that reflects the node Type, and id is a unique integer that identify each node. Node object also have getChildren function that return a list of nodes that are connected to it.


Map object has a function called get2DMap that returns a 2D grid of ObstacleTowerGeneration.LayoutGrammar.Map that consitutes the level layout. Each point in the grid can be a null if empty or a ObstacleTowerGeneration.LayoutGrammar.Cell object if it is not empty. Cell objects has type and node properties; and a getDoor function. type is an enum that reflects if the cell type. node is a reference to the corresponding node from the Mission Graph if the cell type is Normal and null otherwise. getDoor function takes an x dir and y dir then returns an enum that corresponds to the door type in that direction.

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