@osbjs/osbjs/dist/Beatmap/Curves/BezierCurve.js

a minimalist osu! storyboarding framework

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.BezierCurve = void 0;
const Math_1 = require("../../Math");
const Curve_1 = require("./Curve");
class BezierCurve extends Curve_1.Curve {
    constructor(points, precision) {
        super();
        this.points = points;
        this.precision = precision;
        this.startPosition = points[0];
        this.endPosition = points[points.length - 1];
        this.distancePositions = [];
        this.length = this._initLength();
    }
    getPositionAtProgress(t) {
        return this.getPositionAtDistance(this.precision * t);
    }
    getPositionAtDelta(delta) {
        return this.getPositionAtDistance(delta * this.length);
    }
    getPositionAtDistance(distance) {
        let previousDistance = 0.0;
        let previousPosition = this.startPosition;
        let nextDistance = this.length;
        let nextPosition = this.endPosition;
        let i = 0;
        while (i < this.distancePositions.length) {
            let distancePosition = this.distancePositions[i];
            if (distancePosition.distance > distance)
                break;
            previousDistance = distancePosition.distance;
            previousPosition = distancePosition.position;
            i++;
        }
        if (i < this.distancePositions.length - 1) {
            let distancePosition = this.distancePositions[i + 1];
            nextDistance = distancePosition.distance;
            nextPosition = distancePosition.position;
        }
        let delta = (distance - previousDistance) / (nextDistance - previousDistance);
        let prevNext = Math_1.Vector2.sub(nextPosition, previousPosition);
        return Math_1.Vector2.add(previousPosition, Math_1.Vector2.multiplyScalar(prevNext, delta));
    }
    _initLength() {
        let precision = this.points.length > 2 ? this.precision : 0;
        let distance = 0;
        let previousPosition = this.startPosition;
        for (let i = 1; i <= precision; ++i) {
            let delta = i / (precision + 1);
            let nextPosition = this._getPositionAtDelta(delta);
            let prevNext = Math_1.Vector2.sub(nextPosition, previousPosition);
            distance += prevNext.length();
            this.distancePositions.push({ distance, position: nextPosition });
            previousPosition = nextPosition;
        }
        let prevEnd = Math_1.Vector2.sub(this.endPosition, previousPosition);
        distance += prevEnd.length();
        return distance;
    }
    _getPositionAtDelta(delta) {
        let intermediatePoints = [];
        for (let i = 0; i < this.points.length; ++i)
            intermediatePoints[i] = this.points[i];
        for (let i = 1; i < this.points.length; ++i)
            for (let j = 0; j < this.points.length - i; ++j) {
                intermediatePoints[j] = new Math_1.Vector2();
                intermediatePoints[j].x = intermediatePoints[j].x * (1 - delta) + intermediatePoints[j + 1].x * delta;
                intermediatePoints[j].y = intermediatePoints[j].y * (1 - delta) + intermediatePoints[j + 1].y * delta;
            }
        return intermediatePoints[0];
    }
}
exports.BezierCurve = BezierCurve;