Who does this guy think he is?

I’m not a GameMaker programmer, actually. I know a lot about software development and have learned a lot about GameMaker by modding Rusted Moss, but I’m far from an expert. GameMaker is very beginner-focused, which is good for people who want to learn programming, but really bad for someone trying to figure out advanced engine behavior.

If something in the docs is wrong, please let me know so I can fix it and educate myself. Or fix it yourself.

Usage

There are four topics. The Index pages give an overview of each article in a topic. When an article is opened, its headings appear as numbers in the navigation sidebar, and can be clicked to jump around. Links in an article are highlighted in red and always open in the same tab (you can control+click to open in a new tab). An arrow signifies a docs link, and the link icon signifies an external link.

The Single-Page link combines every article into one large page, for easier searching. If you want to find something specific, the Single-Page view can be faster than checking each article individually.

Certain GameMaker keywords are Capitalized, such as Game Object, Instance, Event, Sprite, and Room. This is done to differentiate between Instances, the GameMaker data structure, and instance, the moddable Game Object (omod_instance) referenced as instance in mod files. When “Player” is used by the docs, it refers specifically to oplayer, the Rusted Moss Game Object, not to be confused with player, the moddable omod_player Game Object. It also helps clarify the difference between Game Objects, the GameMaker object-oriented programming class equivalent, and objects, an object-oriented programming structure similar to Instances.

Code Blocks

Inline code blocks are used for code-like segments, such as literal text, files.md, and code = Examples(). Brackets ({ }) in a code block are sometimes used as placeholders, such as create = '{CODE_HERE}' and always use MACRO_CASE. Larger code blocks use syntax highlighting and include the language name and line numbers:

-- A Catspeak code block, the language of modding
let foo = 0

// A GameMaker Language code block, the language of source code
var foo = 0

# A `.ini` file used for Rusted Moss configuration or modding
# Event code is highlighted as Catspeak
code = 'let foo = 0'

A `.md` file used by Rusted Moss Mod Loader
Event code is highlighted as Catspeak
## code
```
let foo = 0
```

Some code segments use an ellipsis (...) to truncate code or use line highlighting for emphasis.

let fn = fun(a, b) {
  -- ellipsis instead of more code
  ...
}

All multi-line code blocks should use two spaces for indentation. GML code blocks are allowed to use the Allman brace style, since it’s what UTMT exports, but all other code should use the One True Brace style. Variable names should use snake_case, if possible.

Comments in code should only be in lowercase, except for special keywords (ie Room). Pseudocode can be used in comments to simplify unnecessary logic, but must use MACRO_CASE and start with an @ (ie // @ IF ( CONDITION ) THEN).

Most of the larger mod examples use Rusted Moss Mod Loader’s syntax, since it supports multiple-line Catspeak code, which is easier for humans to read.

Contribute

The easiest way to contribute is to just message me (Harlem512) on Discord with whatever input you wish to provide, and I’ll probably listen to you. If you want to contribute more directly, you can submit an issue or a pull request. The raw documentation files are here and served from this directory. You can add new articles by creating new mdx files under a directory, however they must have a title, desc (description), and order (used for ordering on the left) field in their frontmatter (the part with ---).

New topics can be made by adding a new directory and an index.mdx file, however I’ll probably reject new topics unless you have a really good idea.

If you like this (or hate it), also reach out. I’d love to know if anyone is actually reading any of this.

Markdown and Magic

The documentation is powered by MDX files, which are basically Markdown with support for embedded Javascript. This makes changing things very easy, since Markdown is basically just plain text; you don’t even need a development environment.

These files then get parsed by Astro, a web framework, which compiles them into raw HTML and generates the actual site you can read.

The docs are best used as a half-width (for a 1920x1080 screen) Firefox browser tab and most of my design decisions are focused on that.

Syntax Highlighting

Syntax highlighted is powered by TextMate grammars, made by me (except for GML highlighting, stolen from Butterscotch Shenanigans). If you’re ambitious, you can take the grammars and make a syntax highlighting extension for your favorite code editor. I leave that as an exercise for the reader (or ask me nicely).