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Cataclysm: Bright Nights


Want to help?

Help is appreciated, especially with:

  • Reporting bugs. Including ones inherited from DDA.
  • Identifying problems that aren’t bugs. Misleading descriptions, values that are clearly off compared to similar cases, grammar mistakes, UI wonkiness that has an obvious solution.
  • Making useless things useful or putting them on a blacklist. Adding deconstruction recipes for things that should have them but don’t, replacing completely redundant items with their generic versions (say, “tiny marked bottle” with just “tiny bottle”) in spawn lists.
  • Tileset work. I’m occasionally adding new objects, like the new electric grid elements, and they could use new tiles.
  • Balance analysis. Those should be rather in depth or “obviously correct”. Obviously correct would be things like: “weapon x has strictly better stats than y, but y requires rarer components and has otherwise identical requirements”.
  • Identifying performance bottlenecks with a profiler.
  • Code quality help.


Contributing to Cataclysm: Bright Nights is easy:

  1. Fork the repository here on GitHub.
  2. Make your changes.
  3. Send us a pull request.


There are a couple of guidelines we suggest sticking to:

  • Add this repository as an upstream remote.
  • Keep your main branch clean. This means you can easily pull changes made to this repository into yours.
  • Create a new branch for each new feature or set of related bug fixes.
  • Never merge from your local branches into your main branch. Only update that by pulling from upstream/main.

Code Style


Code style is enforced across the codebase by astyle. See CODE_STYLE for details.


JSON files are formatted using custom formatter available in tools/format. Visit JSON Style Guide for details.


Markdown files such as doc/ are formatted using deno’s built-in formatter. Run deno fmt anywhere to format markdown files. On VSCode, you can set following configuration to auto-format markdown files on save:

// .vscode/settings.json
  "[markdown]": {
    "editor.formatOnSave": true,
    "editor.defaultFormatter": "denoland.vscode-deno"


Lua files are formatted using dprint’s built-in formatter. Run deno task dprint fmt anywhere to format Lua files. For details, see Lua Style Guide.


The translation of Cataclysm: BN is done using Transifex. Look at the translation project for an up-to-date list of supported languages.

For more information:


Doxygen Comments

Extensive documentation of classes and class members will make the code more readable to new contributors. New doxygen comments for existing classes are a welcomed contribution.

Use the following template for commenting classes:

 * Brief description
 * Lengthy description with many words. (optional)
class foo {


Use the following template for commenting functions:

 * Brief description
 * Lengthy description with many words. (optional)
 * @param param1 Description of param1 (optional)
 * @return Description of return (optional)
int foo(int param1);

Use the following template for commenting member variables:

/** Brief description **/
int foo;

Guidelines for adding documentation

  • Doxygen comments should describe behavior towards the outside, not implementation, but since many classes in Cataclysm are intertwined, it’s often necessary to describe implementation.
  • Describe things that aren’t obvious to newcomers just from the name.
  • Don’t describe redundantly: /** Map **/; map* map; is not a helpful comment.
  • When documenting X, describe how X interacts with other components, not just what X itself does.

Building the documentation for viewing it locally

  • Install doxygen
  • doxygen doxygen_doc/doxygen_conf.txt
  • firefox doxygen_doc/html/index.html (replace firefox with your browser of choice)

Example Workflow

Setup your environment

(This only needs to be done once.)

  1. Fork this repository here on GitHub.

  2. Clone your fork locally.

$ git clone
# Clones your fork of the repository into the current directory in terminal
  1. Set commit message template.
$ git config --local commit.template .gitmessage
  1. Add this repository as a remote.
$ cd Cataclysm-BN
# Changes the active directory in the prompt to the newly cloned "Cataclysm-BN" directory
$ git remote add -f upstream
# Assigns the original repository to a remote called "upstream"

For further details about commit message guidelines please visit:

Update your main branch

  1. Make sure you have your main branch checked out.
$ git checkout main
  1. Pull the changes from the upstream/main branch.
$ git pull --ff-only upstream main
# gets changes from "main" branch on the "upstream" remote

Note If this gives you an error, it means you have committed directly to your local main branch. Click here for instructions on how to fix this issue.

Make your changes

  1. Update your main branch, if you haven’t already.

  2. For each new feature or bug fix, create a new branch.

$ git branch new_feature
# Creates a new branch called "new_feature"
$ git checkout new_feature
# Makes "new_feature" the active branch
  1. Once you’ve committed some changes locally, you need to push them to your fork here on GitHub.
$ git push origin new_feature
# origin was automatically set to point to your fork when you cloned it
  1. Once you’re finished working on your branch, and have committed and pushed all your changes, submit a pull request from your new_feature branch to this repository’s main branch.

Note any new commits to the new_feature branch on GitHub will automatically be included in the pull request, so make sure to only commit related changes to the same branch.

Pull Request Notes

If you file a PR but you’re still working on it, please mark it as draft. This can help speed up our review process by allowing us to only review the things that are ready for it, and will prevent anything that isn’t completely ready from being merged in.

It is not required to solve or reference an open issue to file a PR, however, if you do so, you need to explain the problem your PR is solving in full detail.

Closing issues using keywords

One more thing: when marking your PR as closing, fixing, or resolving issues, please include this somewhere in the description:

- {keyword} #{issue}

for example: - fixed #12345


{keyword} must be one of the following:

  • close, closes, closed
  • fix, fixes, fixed
  • resolve, resolves, resolved


and {issue} is the number of the issue you’re closing after PR gets merged.

This would automatically close the issue when the PR is pulled in, and allows merges to work slightly faster.

closing multiple issues at once

- {keyword} #{issue}, {keyword} #{issue}

See for more.

Tooling support

Various tools are available to help you keep your contributions conforming to the appropriate style. See DEVELOPER_TOOLING for more details.

Advanced Techniques

These guidelines aren’t essential, but they can make keeping things in order much easier.

Using remote tracking branches

Remote tracking branches allow you to easily stay in touch with this repository’s main branch, as they automatically know which remote branch to get changes from.

$ git branch -vv
* main        xxxx [origin/main] ....
  new_feature xxxx ....

Here you can see we have two branches; main which is tracking origin/main, and new_feature which isn’t tracking any branch. In practice, what this means is that git won’t know where to get changes from.

$ git checkout new_feature
Switched to branch 'new_feature'
$ git pull
There is no tracking information for the current branch.
Please specify which branch you want to merge with.

In order to easily pull changes from upstream/main into the new_feature branch, we can tell git which branch it should track. (You can even do this for your local main branch.)

$ git branch -u upstream/main new_feature
Branch new_feature set up to track remote branch main from upstream.
$ git pull
Updating xxxx..xxxx

You can also set the tracking information at the same time as creating the branch.

$ git branch new_feature_2 --track upstream/main
Branch new_feature_2 set up to track remote branch main from upstream.

Note: Although this makes it easier to pull from upstream/main, it doesn’t change anything with regards to pushing. git push fails because you don’t have permission to push to upstream/main.

$ git push
error: The requested URL returned error: 403 while accessing
fatal: HTTP request failed
$ git push origin
xxxx..xxxx  new_feature -> new_feature

Unit tests

There is a suite of tests built into the source tree at tests/ You should run the test suite after ANY change to the game source. An ordinary invocation of make will build the test executable at tests/cata_test, and it can be invoked like any ordinary executable, or via make check. With no arguments it will run the entire test suite. With --help it will print a number of invocation options you can use to adjust its operation.

$ make
... compilation details ...
$ tests/cata_test
Starting the actual test at Fri Nov  9 04:37:03 2018
All tests passed (1324684 assertions in 94 test cases)
Ended test at Fri Nov  9 04:37:45 2018
The test took 41.772 seconds

I recommend habitually invoking make like make YOUR BUILD OPTIONS && make check.

In-game testing, test environment and the debug menu

Whether you are implementing a new feature or whether you are fixing a bug, it is always a good practice to test your changes in-game. It can be a hard task to create the exact conditions by playing a normal game to be able to test your changes, which is why there is a debug menu. There is no default key to bring up the menu so you will need to assign one first.

Bring up the keybindings menu (press Escape then 1), scroll down almost to the bottom and press + to add a new key binding. Press the letter that corresponds to the Debug menu item, then press the key you want to use to bring up the debug menu. To test your changes, create a new world with a new character. Once you are in that world, press the key you just assigned for the debug menu and you should see something like this:

│ Debug Functions - Manipulate the fabric of reality! │
│ i Info                                              │
│ Q Quit to main menu                                 │
│ s Spawning...                                       │
│ p Player...                                         │
│ t Teleport...                                       │
│ m Map...                                            │

With these commands, you should be able to recreate the proper conditions to test your changes. The DDA wiki may have useful informations regarding debug menu.

Frequently Asked Questions

Why does git pull --ff-only result in an error?

If git pull --ff-only shows an error, it means that you’ve committed directly to your local main branch. To fix this, we create a new branch with these commits, find the point at which we diverged from upstream/main, and then reset main to that point.

$ git pull --ff-only upstream main
 * branch            main     -> FETCH_HEAD
fatal: Not possible to fast-forward, aborting.
$ git branch new_branch main          # mark the current commit with a tmp branch
$ git merge-base main upstream/main
cc31d0... # the last commit before we committed directly to main
$ git reset --hard cc31d0....
HEAD is now at cc31d0... ...

Now that main has been cleaned up, we can easily pull from upstream/main, and then continue working on new_branch.

$ git pull --ff-only upstream main
# gets changes from the "upstream" remote for the matching branch, in this case "main"
$ git checkout new_branch

For more frequently asked questions, see the developer FAQ.