party-js/lib/util/rotation.js

A JavaScript library to brighten up your user's site experience with visual effects!

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.rotationToNormal = void 0;
var components_1 = require("../components");
var math_1 = require("../systems/math");
/**
 * Converts the specified euler rotation (in degrees) into the corresponding normal vector.
 *
 * @remarks
 * The normal is calculated by placing a (figurative) plane in a coordinate-system's
 * origin, and rotating it by the specified angles. Note that the z-component of the
 * rotation is irrelevant for the normal and can be ignored. Then, two vectors
 * describing the orientation of the plane are calculated. Their cross product
 * denotes the normal vector.
 *
 * @param rotation The euler rotation angles (in degrees) to calculate the normal for.
 */
function rotationToNormal(rotation) {
    var alpha = rotation.x * math_1.deg2rad;
    var beta = rotation.y * math_1.deg2rad;
    var a = new components_1.Vector(Math.cos(beta), 0, Math.sin(beta));
    var b = new components_1.Vector(0, Math.cos(alpha), Math.sin(alpha));
    return a.cross(b);
}
exports.rotationToNormal = rotationToNormal;