@openhps/core/dist/esm/three/extras/curves/SplineCurve.js

Open Hybrid Positioning System - Core component

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

/**
 * A curve representing a 2D spline curve.
 *
 * ```js
 * // Create a sine-like wave
 * const curve = new THREE.SplineCurve( [
 * 	new THREE.Vector2( -10, 0 ),
 * 	new THREE.Vector2( -5, 5 ),
 * 	new THREE.Vector2( 0, 0 ),
 * 	new THREE.Vector2( 5, -5 ),
 * 	new THREE.Vector2( 10, 0 )
 * ] );
 *
 * const points = curve.getPoints( 50 );
 * const geometry = new THREE.BufferGeometry().setFromPoints( points );
 *
 * const material = new THREE.LineBasicMaterial( { color: 0xff0000 } );
 *
 * // Create the final object to add to the scene
 * const splineObject = new THREE.Line( geometry, material );
 * ```
 *
 * @augments Curve
 */
class SplineCurve extends Curve {
  /**
   * Constructs a new 2D spline curve.
   *
   * @param {Array<Vector2>} [points] -  An array of 2D points defining the curve.
   */
  constructor(points = []) {
    super();

    /**
     * This flag can be used for type testing.
     *
     * @type {boolean}
     * @readonly
     * @default true
     */
    this.isSplineCurve = true;
    this.type = 'SplineCurve';

    /**
     * An array of 2D points defining the curve.
     *
     * @type {Array<Vector2>}
     */
    this.points = points;
  }

  /**
   * Returns a point on the curve.
   *
   * @param {number} t - A interpolation factor representing a position on the curve. Must be in the range `[0,1]`.
   * @param {Vector2} [optionalTarget] - The optional target vector the result is written to.
   * @return {Vector2} The position on the curve.
   */
  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;
  }
}
export { SplineCurve };