@fimbul-works/vec/dist/esm/2d/reflect-2d.js

A comprehensive TypeScript vector math library providing 2D, 3D, and 4D vector operations with a focus on performance and type safety.

import { dot2D } from "./dot-2d.js";
/**
 * Reflects the vector across a normal vector.
 * The normal vector should be normalized (unit length).
 * @param {ArrayVector2D} xy - Vector as `[x, y]` to reflect
 * @param {ArrayVector2D} normal - Normal vector to reflect across (must be normalized)
 * @returns {ArrayVector2D} The reflected vector
 */
export const reflect2D = (xy, normal) => {
    const dot = dot2D(xy, normal);
    return [xy[0] - 2 * dot * normal[0], xy[1] - 2 * dot * normal[1]];
};