plugin.md

The Plugin Architecture in Saohime

Every feature in Saohime is created as a plugin except for the core Entity Component System feature. This make Saohime flexible and extensible.

Default plugins

src/saohime/default_plugins.nim contains the plugins that Saohime need to create a game. Each plugin has its own API.md for documentation.

How to create your own plugin

Let's create your first plugin, HelloPlugin.
First we define the Plugin Object whose name starts with its plugin's name in the plugin's entry point.

type
  HelloPlugin* = object

There is no difference between object and ref object so please choose whichever you want.
Also, you need to create build procedure that takes HelloPlugin as the first argument and World as the second argument.

proc build*(plugin: HelloPlugin, world: World) =
  discard

Now you have created a minimal plugin for Saohime. However, there should be at least a feature or two in HelloPlugin. Let's make a helloSystem that prints "Hello World".

proc helloSystem {.system.} =
  echo "Hello World"

Don't forget to register the systems you defined to the world in build procedure.

proc build*(plugin: HelloPlugin, world: World) =
- discard
+ world.registerStartupSystems(helloSystem)

Finally we can release the plugin and load it in your project. You can confirm that "Hello World" is printed when the app starts.

app.loadPlugin(HelloPlugin)