Creating a Behavior

gladiator-media · June 11, 2023, 2:42am

Is there a way I can create a custom behavior? I like the mesh magnetism behavior. But it doesn’t work for my need 100%.

Takemura · June 11, 2023, 12:57pm

My guess would be to implement Behavior-interface for your custom behavior, like magnetism behavior:

github.com

BabylonJS/Babylon.js/blob/bf9cd4988cd9c67e4082663b1d42f15deda20014/packages/dev/core/src/Behaviors/Meshes/surfaceMagnetismBehavior.ts

import type { PickingInfo } from "../../Collisions/pickingInfo";
import type { PointerInfo } from "../../Events/pointerEvents";
import { PointerEventTypes } from "../../Events/pointerEvents";
import { Quaternion, TmpVectors, Vector3 } from "../../Maths/math.vector";
import type { AbstractMesh } from "../../Meshes/abstractMesh";
import type { Mesh } from "../../Meshes/mesh";
import type { Observer } from "../../Misc/observable";
import type { Scene } from "../../scene";
import type { Nullable } from "../../types";
import type { Behavior } from "../behavior";

/**
 * A behavior that allows a transform node to stick to a surface position/orientation
 * @since 5.0.0
 */
export class SurfaceMagnetismBehavior implements Behavior<Mesh> {
    private _scene: Scene;
    private _attachedMesh: Nullable<Mesh>;
    private _attachPointLocalOffset: Vector3 = new Vector3();
    private _pointerObserver: Nullable<Observer<PointerInfo>>;

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Here is the interface:

github.com

BabylonJS/Babylon.js/blob/bf9cd4988cd9c67e4082663b1d42f15deda20014/packages/dev/core/src/Behaviors/behavior.ts

import type { Nullable } from "../types";

/**
 * Interface used to define a behavior
 */
export interface Behavior<T> {
    /** gets or sets behavior's name */
    name: string;

    /**
     * Function called when the behavior needs to be initialized (before attaching it to a target)
     */
    init(): void;
    /**
     * Called when the behavior is attached to a target
     * @param target defines the target where the behavior is attached to
     */
    attach(target: T): void;
    /**
     * Called when the behavior is detached from its target

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gladiator-media · June 11, 2023, 1:39pm

That’s what I needed. Thank you

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Creating a Behavior

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