Yarnspin is a simple story-telling engine, with its own built-in scripting language and graphics processing, turning hi-res photos into palettized low-res pixels.

There is a custom script language, which allows you to define dialogs with options, and set up locations with descriptions and images. It comes with a thousand portrait images included, and you can of course add your own.

Yarnspin games runs on Windows, Mac, Linux, and in browsers using web assembly.

The documentation is pretty thin at the moment - there's just this readme, which is very much work-in-progress and likely incomplete - but it comes with an example "game" which is also a tutorial explaining the key concepts. There is also a small game made with Yarnspin, called No Sunshine, and it is open source and available here https://github.com/mattiasgustavsson/no_sunshine

Documentation

The documentation for Yarnspin can be found here: docs/yarnspin.md

Building the code

No build system is used, simply call the compiler from the commandline.

Windows

From a Visual Studio Developer Command Prompt, do:

  cl source\yarnspin.c

For building the final release version, you probably want all optimizations enabled. There's a helper script (a windows bat file) in the build folder of the repo, which will build with full optimizations, and also include an application icon. It will also call the compiled exe to generate the yarnspin.dat data file, and then append the file to the end of the executable, giving you a single exe you can distribute which contains both code and data. No need to include the yarnspin.dat file. See the build\build_win.bat file for details.

Mac

  clang source/yarnspin.c `sdl2-config --libs --cflags` -lGLEW -framework OpenGL -lpthread

SDL2 and GLEW are required - if you don't have them installed you can do so with Homebrew by running

  brew install sdl2 glew  

Linux

  gcc source/yarnspin.c `sdl2-config --libs --cflags` -lGLEW -lGL -lm -lpthread

SDL2 and GLEW are required - if you don't have them installed you can do so on Ubuntu (or wherever apt-get is available) by running

  sudo apt-get install libsdl2-dev
  sudo apt-get install libglew-dev

WebAssembly

Using WAjic:

  wasm\node wasm/wajicup.js -embed yarnspin.dat yarnspin.dat source/yarnspin.c yarnspin.html

Note that you must have generated the yarnspin.dat file (by running the yarnspin executable once) before running this build command.

A WebAssembly build environment is required. You can download it (for Windows) here: wasm-env. Unzip it so that the wasm folder in the zip file is at your repository root.

The wasm build environment is a compact distribution of node, clang/wasm-ld, WAjic and wasm system libraries.

For a final release, you probably want the web page it is embedded on to look a bit nicer - there is a helper build script build\build_web.bat which does this, specifying a template html file.