System

Note: This documentation is for the old 0.2.0 version of A-Frame. Check out the documentation for the current 1.6.0 version

Note: the systems API is new and may be unstable.

A system, of the entity-component-system pattern, provides global scope, services, and management to classes of components. It provides public APIs (methods and properties) for classes of components. A system can be accessed through the scene element, and can help components interface with the global scene.

For example, the camera system manages all entities with the camera component, controlling which camera is the active camera.

Registering a System

A system is registered similarly to a component. If the system name matches a component name, then the component will have a reference to the system as this.system:

AFRAME.registerSystem('my-component', {
  // System handlers and methods.
});

AFRAME.registerComponent('my-component', {
  init: function () {
    console.log(this.system);
  }
});

Methods

A system, like a component, defines lifecycle handlers. It can also define methods intended to be public API.

Method	Description
init	Called once when the system is initialized. Used to initialize.
pause	Called when the scene pauses. Used to stop dynamic behavior.
play	Called when the scene starts or resumes. Used to start dynamic behavior.
tick	If defined, will be called on every tick of the scene’s render loop.

Accessing a System

An instantiated system can be accessed through the scene:

console.log(document.querySelector('a-scene').systems);

Registered system prototypes can be accessed through AFRAME.systems.