/**
 * Pseudo-noise + smooth-noise — pure functions, deterministic, seedable.
 *
 * Extracted 2026-04-27 to dedupe identical implementations between
 * `engines/cloth-verlet.ts` and `runtime/src/traits/PhysicsTraits.ts`
 * (per /critic batch-6 Annoying #8: "two sources of truth for what is
 * supposed to be deterministic noise"). All callers now import from
 * here.
 *
 * The noise function is the classic `sin * 43758.5453` hash — fast,
 * deterministic, no allocations, no Math.random. Suitable for Verlet
 * cloth wind, soft-body turbulence, fluid agitation. NOT cryptographic.
 *
 * Domain: t and seed are real numbers; output is in [-1, 1].
 */
/**
 * Hash-style 1D noise. Deterministic for any (t, seed) pair.
 * Output: [-1, 1].
 */
export declare function noise(t: number, seed: number): number;
/**
 * Smoothstep-interpolated noise. Continuous and C1 across integer t boundaries.
 * Output: [-1, 1].
 */
export declare function smoothNoise(t: number, seed: number): number;