toosoon-utils/lib/extras/curves/SplineCurve.js

Utility functions & classes

import { catmullRom } from '../../geometry';
import Curve from './Curve';
/**
 * Utility class for manipulating splines
 *
 * @exports
 * @class SplineCurve
 * @extends Curve
 */
export default class SplineCurve extends Curve {
    type = 'SplineCurve';
    points = [];
    /**
     * @param {Point[]} [points] Array of points defining the curve
     */
    constructor(points = []) {
        super();
        this.points = points;
    }
    /**
     * Interpolate a point on the Spline curve
     *
     * @param {number} t Normalized time value to interpolate
     * @returns {Point} Interpolated coordinates on the curve
     */
    getPoint(t) {
        const points = this.points;
        const p = (points.length - 1) * t;
        const index = Math.floor(p);
        const weight = p - index;
        const p1 = points[index === 0 ? index : index - 1];
        const cp1 = points[index];
        const cp2 = points[index > points.length - 2 ? points.length - 1 : index + 1];
        const p2 = points[index > points.length - 3 ? points.length - 1 : index + 2];
        const point = catmullRom(weight, ...p1, ...cp1, ...cp2, ...p2);
        return point;
    }
}