notnull games

• Template: cart_c - press "Use this template" and you have a working game.
• Docker image: ghcr.io/notnullgames/null0-cart-c:latest
• Your code: cart/main.c, compiled with wasi-sdk clang
• Bindings: carts/c/null0.h (baked into the docker image for you)
• WASI is available, so ordinary file and stdio calls work.
• See carts made with C
• API docs for C

building

You do not install wasi-sdk clang - the docker image has it, and the current null0 bindings, baked in. There is nothing in your project to keep in sync with the engine.

docker run --rm --user $(id -u):$(id -g) \
  -v ./cart:/src -v ./webroot:/out \
  ghcr.io/notnullgames/null0-cart-c:latest mygame

The template wraps that in npm start, which also serves the result and rebuilds when you save.

C notes

• #include "null0.h" and you have the whole API. main() works as a load() if you prefer it.
• Call fflush(stdout) if you want printf output to survive a cart being killed.

a cart, in C

This is carts/c/simple/main.c in the engine repo - the same file CI builds into the cart below, so it always compiles.

#include "null0.h"

// every language's `simple` cart draws exactly this, so you can put any two
// of them side by side and see only the language differ

int main() {
  clear(BLUE);
  draw_circle(100, 100, 50, RED);
  draw_text(FONT_DEFAULT, "hello from C", 170, 92, WHITE);
  return 0;
}

// callbacks (optional - implement as needed)

// void update() {}
// void unload() {}
// void buttonUp(GamepadButton button, u32 player) {}
// void buttonDown(GamepadButton button, u32 player) {}
// void keyUp(Key key) {}
// void keyDown(Key key) {}
// void mouseDown(MouseButton button) {}
// void mouseUp(MouseButton button) {}
// void mouseMoved(f32 x, f32 y) {}

callbacks

A cart implements the callbacks it cares about. In C they look like this:

void update() {}

See anatomy of a cart for the full list and what each one is passed.