A template for creating Space Haven mods by patching game logic at runtime
Java 17+ is currently required. Any implementation is fine, but I used this one: https://adoptium.net/temurin/releases/
This must be the first Java environment found, so you can set the JAVA_HOME environment variable to point to the "home" folder inside of the Java installation directory
This is the build tool you will use to build your mods. You can install it from a package manager (homebrew for MacOS, scoop for Windows, etc.) or you can follow the instructions here: https://maven.apache.org/install.html
You can verify that it was installed properly by opening a terminal/PowerShell window and running mvn --version. The output should look similar to:
Apache Maven 3.9.3 (21122926829f1ead511c958d89bd2f672198ae9f)
Maven home: /opt/homebrew/Cellar/maven/3.9.3/libexec
Java version: 17.0.8, vendor: Eclipse Adoptium, runtime: /Library/Java/JavaVirtualMachines/temurin-17.jdk/Contents/Home
Default locale: en_US, platform encoding: UTF-8
OS name: "mac os x", version: "14.0", arch: "x86_64", family: "mac"git clone https://github.com/CyanBlob/SpaceHavenModTemplate
This is required for AspectJ and Maven to locate the game's classes. I cannot add the game's .jar file to this repo for obvious reasons.
First, navigate into the repo with cd /path/to/SpaceHavenModTemplate. Then, add the file with
mvn install:install-file -DgroupId="fi.bugbyte" -DartifactId=spacehaven -Dpackaging=jar -Dversion=1.0.0 -Dfile="</path/to/spacehaven.jar>" -DgeneratePom=true
Make sure to use the correct file path in the -Dfile argument above.
Note: On MacOS, the game is shipped as a .app file. Don't panic, just give the path as </path/to/spacehaven.app/Contents/Resources/spacehaven.jar
This project uses AspectJ to provide code injection when the game loads. There are some simple example mods in src/main/java/com/cyanblob/SpaceHavenMod. Aside from those, here are some useful links:
https://eclipse.dev/aspectj/doc/released/devguide/ltw-configuration.html
https://eclipse.dev/aspectj/doc/released/adk15notebook/ataspectj-pcadvice.html
The general idea is that we define locations where we want code to be inject ("pointcuts") and can then run code before, after, or around that location. The "around" pointcut is the most powerful because you can decide whether or not to run the original code via the proceed function. See guiAspect.java as an example of this
Note that AspectJ provides two modes: an annotation mode that uses annotations in .java files and another style that uses .aj files with custom syntax. I was only able to get load time weaving (LTW) working with the annotations, but it may be possible to use the .aj files as well
Make sure to edit src/main/resources/META-INF/aop.xml to get your mod picked up by AspectJ!
Building is simple. From within the SpaceHavenModTemplate directory, run: mvn package
If all goes well, you will have a .jar file created in the target directory. This is the mod file.
Use the latest version of the mod loader, or follow the instructions below:
Navigate to the directory containing spacehaven.jar. You can open this directory by right-clicking the game in your Steam library, then clicking Manage -> Browse Local Game Files
Note: On MacOS this will take you to a directory containing spacehaven.app instead of spacehaven.jar. Just right-click the .app file and select "Show Package Contents". Then go into "Contents/Resources" to find the .jar file
Inside the directory containing the .jar file, create a folder named "mods". This is where you will place your mods.
Then, download aspectj-1.9.19.jar and aspectjweaver-1.9.19 from here and here, respectively. Place these files in the same folder as spacehaven.jar (NOT the mods folder)
Then, copy the config.json file from SpaceHavenModTemplate/copy_to_game_dir into the same folder as spacehaven.jar. You will have to overwrite the existing file
Lastly, edit config.json to add an entry for every mod you wish to use in the classPath section. It should include the "mod" part of the path, i.e. "mods/my_really_cool_mod.jar". Make sure to add a comma at the end of each entry in the classPath section aside from the last entry in the list
You can now run the game as normal directly from Steam. Enjoy!