Skip to main content

Create Component

Let's create our Component and add them to the GameObject

tip

Component corresponds to Unity's MonoBehaviour class.

Rotator Component​

Let's make a component that rotates objects at a constant speed

./src/asset/script/Rotator.ts
import { Component } from "the-world-engine";

export class Rotator extends Component {
    private readonly _rotationSpeed: number = 1;
    
    public update(): void { // update is called once per frame
        this.gameObject.transform.rotateZ(
            this._rotationSpeed * this.engine.time.deltaTime);
    }
}

then we can add it to our GameObject

./src/asset/Bootstrapper.ts
//...
.withChild(instantiater.buildGameObject("sprite1", new Vector3(0, 0, 0))
    .withComponent(CssSpriteRenderer, c => {
        c.asyncSetImageFromPath("https://c.tenor.com/jJalYO9p0PAAAAAd/hatsune-miku-plush.gif");
        c.imageWidth = 6;
        c.imageHeight = 6;
    })
    .withComponent(Rotator))
//...

Component Messages​

the component messages are called when the gameObject meets certain conditions.

The list below is a list of the available messages.

Basic Messages​

These are the most commonly used messages.

  • awake: awake is called when the script instance is being loaded.
  • start: start is called on the frame when a script is enabled just before any of the update methods are called the first time.
  • update: update is called every frame, if the Component is enabled.
  • onDestroy: Destroying the attached Component will result in the game or Scene receiving onDestroy.
  • onEnable: This function is called when the object becomes enabled and active.
  • onDisable: This function is called when the behaviour becomes disabled.

Physics Messages​

These are the messages related to game engine built-in physics engine(box2d).

  • onCollisionEnter2D: Sent when an incoming collider makes contact with this object's collider (2D physics only).
  • onCollisionExit2D: Sent when a collider on another object stops touching this object's collider (2D physics only).
  • onCollisionStay2D: Sent each frame where a collider on another object is touching this object's collider (2D physics only).
  • onTriggerEnter2D: Sent when another object enters a trigger collider attached to this object (2D physics only).
  • onTriggerExit2D: Sent when another object leaves a trigger collider attached to this object (2D physics only).
  • onTriggerStay2D: Sent each frame where another object is within a trigger collider attached to this object (2D physics only).

Unsafe Messages​

If you add or remove GameObjects or Components within this messages, proper behavior is not guaranteed (performance reasons).

  • onWorldMatrixUpdated: This function is called when the world matrix is updated.