import type { Vec3 } from "./geometry.js";
/** Sum of two 3D vectors.
 * @internal
 */
export declare function add(a: Vec3, b: Vec3): Vec3;
/** Difference `a - b` of two 3D vectors.
 * @internal
 */
export declare function sub(a: Vec3, b: Vec3): Vec3;
/** Scale a 3D vector by a scalar.
 * @internal
 */
export declare function scale(a: Vec3, s: number): Vec3;
/** Negate a 3D vector.
 * @internal
 */
export declare function negate(a: Vec3): Vec3;
/** Dot product of two 3D vectors.
 * @internal
 */
export declare function dot(a: Vec3, b: Vec3): number;
/** Cross product `a × b` of two 3D vectors.
 * @internal
 */
export declare function cross(a: Vec3, b: Vec3): Vec3;
/** Euclidean length of a 3D vector.
 * @internal
 */
export declare function length(a: Vec3): number;
/** Squared length of a 3D vector; cheaper than `length` when only comparing magnitudes.
 * @internal
 */
export declare function lengthSquared(a: Vec3): number;
/** Unit vector in the direction of `a`; returns the zero vector when `a` has no length.
 * @internal
 */
export declare function normalize(a: Vec3): Vec3;
/** Distance between two points.
 * @internal
 */
export declare function distance(a: Vec3, b: Vec3): number;
/** Squared distance between two points; cheaper than `distance` for radius comparisons on hot paths.
 * @internal
 */
export declare function distanceSquared(a: Vec3, b: Vec3): number;
/** Linearly interpolate between points `a` and `b` by fraction `t`.
 * @internal
 */
export declare function lerp(a: Vec3, b: Vec3, t: number): Vec3;