C Code Organization, Naming Conventions, and Formatting

Category: SDL Adventure Game

Game Scene

A game scene is a collection of functions and state that models a single scene in the game. For instance, in the game there will be four scenes:

  1. Intro - Title screen and main menu
  2. Playground Entrance - The fox needs to find a way to enter the playground
  3. Playground - The fox must fix the slide with help from her friend, the squirrel
  4. Outro

Each scene must implement these functions:

  1. init - Initializes scene state
  2. load_media - Loads media such as images, sprites, and sounds
  3. Game loop
    1. process_input - Event handling
    2. update - Updates the scene state
    3. render - Renders scene graphical objects
  4. deinit - Destroys objects allocated in memory

C Code Organization

So far, I was declaring and implementing all scene functions in main.c.

I decided to organize the functions of each scene into its own file: intro.c, playground_entrance.c, etc., but I wasn’t too sure about how to do this in C.

C doesn’t have namespaces; as a workaround, I initially used a prefix for the functions in each scene. For example, intro_init for the init function of the intro scene, and so on.

I wasn’t sure if I could just #include a .c file directly, but I’ve read that’s an anti-pattern. Instead, I created a .c file and a corresponding .h file with the function declarations.

There is no explicit concept of public and private visibility in C. However, the way I interpreted it was by declaring only functions in the .h file that would be visible outside the scene file scope. In the .c file, I implemented the functions declared in the header file and, if necessary, static functions that would only be accessible within the scene file scope.

By default, Xcode wrapped the .h file content in a #ifndef directive to ensure the same file isn’t imported twice. However, that’s optional, and if I import the same file twice, I should get an error. Note: Rob Pike is against this style.

C Naming Conventions

I found a couple of useful resources about naming conventions in C:

In the project, I’m using a couple of conventions:

  1. typedef types use CamelCase
  2. Variable names use snake_case

C Code Formatting

I’m manually using clang-format to format C code. Example: clang-format -i image.c.

I tried to create a macOS automation and set a keyboard shortcut, but it didn’t work as expected.

I’m using this CLI command to format all files in the project:

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find sdlexample -name '*.c' -o -name '*.h' | xargs -I {} clang-format -i {}

clang-format Style for Struct Initialization

I didn’t like the default format used by clang-format for struct initialization. I would prefer each field to be on a new line. There is a configuration to change the default behavior, but I ultimately just stuck with the default for simplicity.

I also tried to install a more recent version of clang-format, but it failed because I don’t have a recent enough version of Xcode command-line tools:

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You should download the Command Line Tools for Xcode 13.2.1

I have Xcode 12, and I can’t install a newer version because it isn’t supported by the operating system (OSX 11.7).

Next: Images and Sprites