backend/libs/three/extras/curves/SplineCurve.js

import { Curve } from '../core/Curve.js';
import { CatmullRom } from '../core/Interpolations.js';
import { Vector2 } from '../../math/Vector2.js';

class SplineCurve extends Curve {
	constructor(points = []) {
		super();

		this.type = 'SplineCurve';

		this.points = points;
	}

	getPoint(t, optionalTarget = new Vector2()) {
		const point = optionalTarget;

		const points = this.points;
		const p = (points.length - 1) * t;

		const intPoint = Math.floor(p);
		const weight = p - intPoint;

		const p0 = points[intPoint === 0 ? intPoint : intPoint - 1];
		const p1 = points[intPoint];
		const p2 = points[intPoint > points.length - 2 ? points.length - 1 : intPoint + 1];
		const p3 = points[intPoint > points.length - 3 ? points.length - 1 : intPoint + 2];

		point.set(CatmullRom(weight, p0.x, p1.x, p2.x, p3.x), CatmullRom(weight, p0.y, p1.y, p2.y, p3.y));

		return point;
	}

	copy(source) {
		super.copy(source);

		this.points = [];

		for (let i = 0, l = source.points.length; i < l; i++) {
			const point = source.points[i];

			this.points.push(point.clone());
		}

		return this;
	}

	toJSON() {
		const data = super.toJSON();

		data.points = [];

		for (let i = 0, l = this.points.length; i < l; i++) {
			const point = this.points[i];
			data.points.push(point.toArray());
		}

		return data;
	}

	fromJSON(json) {
		super.fromJSON(json);

		this.points = [];

		for (let i = 0, l = json.points.length; i < l; i++) {
			const point = json.points[i];
			this.points.push(new Vector2().fromArray(point));
		}

		return this;
	}
}

SplineCurve.prototype.isSplineCurve = true;

export { SplineCurve };