Entity and Component

The core of Orillusion is inspired by the ECS structure, and follows the principle of Composition over inheritance. Implemented own component system. We divide the traditional complex logic into independent and reusable parts. Each part can be encapsulated and run independently. Then, by flexible combination, multiple simple components are combined to perform complex functions and logic.

Entity

Entity is a container for components to connect various components. It doesn't have actual function and will not render or express any functions if no components are added to it. In practice, we will not operate Entity directly. Usually, we use Object3D and Scene3D as scene container nodes to connect various components.

Compnent

Component is a series of reusable modules or data. All the functions of Entity are implemented by loading Component. By defining the logic callback and lifecycle of the component, we can freely combine different components to make the Entity have different functions, such as:

• a camera = Position + Rotation + Camera3D
• a bulb = Position + Rotation + PointLight + Shadow
• a box = Position + Rotation + Scale + BoxGeometry + Material

Among them, all components are independent and equal, and each performs a single function. This split makes the Position and Rotation modules reusable, and they can be combined as needed, which greatly improves the efficiency of code reuse, and also effectively reduces the coupling between modules.

Built-in Components

We have built-in a lot of basic components in the Orillusion engine, which encapsulates a lot of basic functions. For example, Object3D has already built-in the Transform component, which contains the Position, Rotation, Scale and other related functions. Make it convenient for users to operate the spatial transformation of Object3D.

These are the commonly used built-in components in the Orillusion engine:

Name	Description
Camera3D	Camera component, set the camera node
Transform	Transform component, used to control the matrix coordinate transformation of the object
HoverCameraController	Camera controlort, used to control the position and orientation of the camera
MeshRenderer	Mesh renderer component, used to render meshes and materials
DirectLight	Directional light, set the type and parameters of the directional light
PointLight	Point light source, set the type and parameters of the point light
SpotLight	Spotlight, set the type and parameters of the spotlight
ColliderComponent	Collider component, used to detect collisions
SkeletonAnimationComponent	Skeleton animation component, used to control animation playback
AtmosphericComponent	Atmospheric skybox component

And more built-in components can be found in Components

Basic Usage

//Create a new entity
let obj = new Object3D();
//Add the entity to scene
scene.addChild(obj);

Add Component

let obj = new Object3D();
let light = obj.addComponent(DirectLight)

Delete Component

let obj = new Object3D();
let light = obj.removeComponent(DirectLight)

Disable Component

let obj = new Object3D();
let light = obj.getComponent(DirectLight)
light.enable = false

Enable Component

let obj = new Object3D();
let light = obj.getComponent(DirectLight)
light.enable = true

Lifecycle of Component

The component extends from the CompnentBase, which defines several basic lifecycles:

Lifecycle	Description
init	Component initialization, only run once when the component is created
start	Component starts running, only called before the first onUpdate
stop	Component runs before destruction
onUpdate	Component runs every frame
onBeforeUpdate	Component runs before rendering update
onLateUpdate	Component runs after rendering update
onEnable	Work when enable = true , component joins the main loop update
onDisable	Work when enable = false , component will no longer trigger loop

Users can extend different custom functions by inheriting the ComponentBase base class, see Script Component for details.