Project Overview
Dungeon generation has long been a staple of many classic games, especially those in the ASCII tradition like Rogue and NetHack. These games feature sprawling, randomly-generated dungeons with interconnected rooms and pathways, each offering a new experience with every playthrough. I’ve always been intrigued by this concept and wanted to try my hand at creating a dungeon generation algorithm that felt natural, engaging, and had a bit of character. While the most straightforward approaches often involve generating rooms first and then connecting them, I decided to take a more nuanced approach to ensure that the dungeons felt dynamic and unpredictable.
For this project, I chose Unity to speed up the rendering process and make the dungeon more visually appealing and intuitive to interact with. While generating dungeons in ASCII would’ve been simpler, Unity’s graphical tools allowed me to build a dungeon that could be explored more easily, and its coroutines provided a handy way to animate the generation process. My goal was to create a visually rich dungeon with intelligent connectivity, offering a good balance between complexity and clarity.
Tools and Technologies: Unity, C#, and a Touch of Algorithmic Magic
I wanted to keep the focus of the project on dungeon generation itself, so I chose tools that would help me get to that goal quickly while keeping the process flexible and adaptable.
Unity for Rendering and Animation
- Graphics and Interaction: Although Unity is commonly used for games, its graphical rendering capabilities make it a fantastic tool for visualizing procedural content like a dungeon. By using sprites instead of ASCII characters, the layout becomes more readable and visually appealing.
- Coroutines for Smooth Generation: Unity’s coroutines allowed me to animate the dungeon’s generation process step by step, providing a visual insight into how the dungeon is built. This made the whole process feel more interactive and dynamic for the player.
- Tile System: Unity’s powerful object system was perfect for representing individual tiles in the dungeon grid. Each tile was a game object, allowing me to manage their states and easily update them during the dungeon generation process.
C# for Logic and LINQ for Efficiency
The heavy lifting of the project was done in C#, leveraging the simplicity and power of LINQ to streamline tasks like filtering collections and handling operations across multiple elements. This was crucial for keeping my dungeon generation code clean, readable, and focused on what mattered: generating an interesting dungeon.
- Tile Data Structure: Each tile in the dungeon is represented by a custom data structure containing properties such as the tile’s position, its current state (room, path, wall, etc.), and a region number that links tiles together logically.
- LINQ for Collection Operations: LINQ made operations on collections (like filtering tiles) much more concise. For example, finding surrounding tiles or filtering out non-wall tiles for path creation became much simpler thanks to LINQ’s power.
Building the Dungeon: Step-by-Step Algorithm
The core of this project lies in the algorithm for generating the dungeon. Rather than relying on pathfinding or rigid room placement, I sought a more organic approach to ensure that each dungeon felt unique, with a sense of randomness but still with a clear structure.
Step 1: Room Generation
The first task was to create the rooms, the foundation of any dungeon. I wanted rooms that felt natural but weren’t restricted by a grid-like layout.
- Random Room Placement: I randomly selected positions for rooms and their dimensions, ensuring they didn’t overlap with existing rooms or exceed the grid’s boundaries. I restricted the number of attempts to place a room (set by the user) to avoid infinite loops, which gave the dungeon a manageable density of rooms.
- Controlling Dungeon Density: Rather than limiting the dungeon to a specific number of rooms, I gave the user control over how dense the dungeon should be by allowing them to set a maximum number of placement attempts. This gives flexibility while maintaining control over the dungeon’s layout.
Step 2: Path Generation (Not Your Average Maze)
Once the rooms were in place, the next challenge was to connect them in a way that felt fluid and natural. The goal here was to avoid creating obvious, straight-line paths, which could make the dungeon feel artificial.
- Maze Generation: To connect the rooms, I chose to use a maze generation algorithm. Specifically, I employed a Depth-First Search (DFS) method, which creates winding, organic pathways. This was a bit unconventional compared to pathfinding algorithms, which are often used in procedural generation. The DFS algorithm made the dungeon feel less like a grid and more like a true maze.
- Flood Fill: Before starting the maze generation, I used a linear flood fill to fill in the empty spaces between the rooms. This process started at a random tile and filled horizontally before checking vertical spaces, ensuring that the area between rooms was filled with wall tiles.
- Depth-First Search: The DFS algorithm then carved out paths from random tiles, marking visited tiles and adding them to a stack. This recursive approach creates a maze with winding, dead-end corridors—adding to the dungeon’s complexity.
Step 3: Connecting the Rooms
At this point, the maze filled the empty spaces between rooms, but rooms still needed to be interconnected. I assigned each tile a region number to indicate which room or path it was part of.
- Creating Doorways: Tiles adjacent to multiple regions (i.e., walls separating two regions) were identified as potential doorways. I then selected random potential doorways and designated them as “doors,” allowing players to transition between rooms seamlessly.
- Adding Random Doors: To keep the dungeon interesting, I added randomness by occasionally turning previously removed connectors into additional doors, meaning some rooms could have multiple ways in and out.
Step 4: Cleaning Up Dead Ends
After the maze and rooms were connected, the dungeon still had some overly complex or confusing pathways. I decided to clean up dead ends, paths that lead nowhere, to simplify navigation.
- Pruning Dead Ends: I set a parameter to remove dead-end paths while preserving connectivity. The user can adjust how many of these dead-end paths remain, striking a balance between exploration and clarity.
Challenges and Solutions
While the algorithm itself was relatively straightforward, there were a few hiccups during the implementation:
- Tile Management: Handling the grid of tiles while ensuring everything was displayed correctly was tricky, especially when taking into account varying grid sizes. The initial tile scaling wasn’t perfect, and there were occasional grid lines visible. However, after some adjustments, I found a good balance for a visually consistent display.
- Performance Optimization: Generating the dungeon in real-time can be computationally expensive. By animating the process with Unity’s coroutines, I kept the user engaged without overloading the system with complex calculations in a single frame.
- Maze Complexity: The initial paths created by the DFS algorithm were very winding, which looked great but made some sections of the dungeon a bit too convoluted. I added a tweak where the algorithm would sometimes choose to continue in a straighter line, giving the dungeon a mix of winding and more straightforward paths.
Conclusion: A Dynamic, Interactive Dungeon Generator
This project was a great exercise in exploring procedural content generation. By combining traditional maze algorithms with random room placement and intelligent pathfinding, I was able to create dungeons that feel both structured and natural. The use of Unity to visually render the dungeon and animate the generation process brought the entire project to life in a way that would be difficult to achieve with ASCII.
By experimenting with different approaches to path and room generation, I learned a lot about the intricacies of procedural generation and how small tweaks can lead to vastly different dungeon layouts. As a result, the generated dungeons are varied, dynamic, and much more engaging than a simple pathfinding solution would have provided.
You can view the full code on GitHub and see the full details behind the algorithm in my reference materials.
Code:
View on GitHub
Reference:
https://journal.stuffwithstuff.com/2014/12/21/rooms-and-mazes/
https://en.wikipedia.org/wiki/Flood_fill