@woosh/meep-engine/src/engine/intelligence/behavior/util/RotationBehavior.js

Pure JavaScript game engine. Fully featured and production ready.

import { EntityBehavior } from "../ecs/EntityBehavior.js";
import { Transform } from "../../../ecs/transform/Transform.js";
import Vector3 from "../../../../core/geom/Vector3.js";
import Quaternion from "../../../../core/geom/Quaternion.js";
import { BehaviorStatus } from "../BehaviorStatus.js";

export class RotationBehavior extends EntityBehavior {
    constructor() {
        super();

        /**
         * Rotation per second
         * @type {Vector3}
         */
        this.axis = new Vector3();
        this.speed = 1;

        this.angle = 0;

        this.__offset = new Quaternion();
    }

    static fromJSON(j) {
        const r = new RotationBehavior();

        r.fromJSON(j);

        return r;
    }

    /**
     *
     * @param axis
     * @param speed
     * @param angle
     */
    fromJSON({ axis = Vector3.up, speed = 1, angle = 0 }) {
        this.axis.fromJSON(axis);
        this.speed = speed;
        this.angle = angle;
    }

    initialize(context) {
        super.initialize(context);


        const transform = this.ecd.getComponent(this.entity, Transform);
        this.__offset.copy(transform.rotation);
    }

    tick(timeDelta) {
        /**
         *
         * @type {Transform}
         */
        const transform = this.ecd.getComponent(this.entity, Transform);

        const angleDelta = this.speed * timeDelta;

        this.angle += angleDelta;

        const r = transform.rotation;

        r.fromAxisAngle(this.axis, this.angle);
        r.multiplyQuaternions(r, this.__offset);

        return BehaviorStatus.Running;
    }
}