import type { AxisInput } from "../input/axisInput.js";
/** How the boat turns: a rudder needs water flowing past it; an outboard swings its own thrust. */
export type BoatSteering = {
    kind: "rudder";
    /** Rudder area, m². */
    area: number;
    /** Largest rudder angle, rad (default `0.6`). */
    maxAngle?: number;
    /** Share of prop thrust that washes over the rudder as flow, `0..1` (default `0.5`) — steering at low speed. */
    propWash?: number;
} | {
    kind: "outboard";
    /** Largest thrust angle, rad (default `0.5`). */
    maxAngle?: number;
};
/**
 * A powered hull in physical units. Drag rises toward hull speed (`√(g·L)·1.34`) and then falls away once the hull
 * planes, the keel resists sliding sideways, and the prop's thrust fades as the boat approaches the prop's speed.
 */
export interface BoatTuning {
    /** Displacement, kg. */
    massKg: number;
    /** Waterline length, m; sets hull speed and the rudder's lever arm. */
    length: number;
    /** Beam, m; sets the visual roll response. */
    beam: number;
    /** Peak prop thrust, N. */
    maxThrust: number;
    /** Speed at which prop thrust reaches zero, m/s. */
    propSpeed: number;
    /** Reverse thrust as a share of `maxThrust` (default `0.4`). */
    reverseScale?: number;
    /** Hull drag coefficient × wetted frontal area, m², before planing (default `0.3 · beam`). */
    dragArea?: number;
    /** Speed where the hull planes and drag drops, m/s; omit for a displacement hull that never planes. */
    planingSpeed?: number;
    /** Drag multiplier once fully planing, `0..1` (default `0.35`). */
    planingDrag?: number;
    /** Keel lateral resistance, N per (m/s)² of sideways speed (default `massKg · 6`). */
    keel?: number;
    /** Extra yaw damping, N·m per rad/s, on top of the keel resisting rotation along the hull (default `0`). */
    yawDamping?: number;
    steering: BoatSteering;
    /** Rudder or outboard slew rate, rad/s (default `2`). */
    steerRate?: number;
    /** Largest bow-up pitch while climbing onto the plane, rad (default `0.12`). */
    bowRise?: number;
    /** Largest heel in a hard turn, rad (default `0.15`); planing hulls lean into the turn. */
    maxHeel?: number;
    /** Integration substep, s (default `1/240`). */
    maxSubstep?: number;
}
/** World hooks for a boat instance. */
export interface BoatOptions {
    position?: readonly [number, number, number];
    heading?: number;
    /** Water surface height, m, under a point at a time (waves); default flat at the spawn height. */
    waterHeight?: (x: number, z: number, time: number) => number;
    /** Surface current, m/s, `[vx, vz]`; the hull drags toward it. */
    current?: (x: number, z: number) => readonly [number, number];
}
/** Serializable boat state. */
export interface BoatState {
    x: number;
    y: number;
    z: number;
    heading: number;
    vx: number;
    vz: number;
    yawRate: number;
    steerAngle: number;
    time: number;
    bodyPitch: number;
    bodyRoll: number;
}
/** One boat tick: pose plus the telemetry wake, spray and engine sound read. */
export interface BoatStep {
    position: readonly [number, number, number];
    heading: number;
    forwardSpeed: number;
    lateralSpeed: number;
    yawRate: number;
    /** Rudder or outboard angle, rad, positive steers like `steer > 0`. */
    steerAngle: number;
    /** `0` displacement … `1` fully planing. */
    planing: number;
    /** Thrust in use as a share of `maxThrust`, `0..1` — engine load. */
    engineLoad: number;
    bodyPitch: number;
    bodyRoll: number;
    /** Always `0`: the hull rides the water surface. Present so `tickDrivableVehicle` can drive it. */
    airOffset: number;
    airborne: boolean;
}
/** A force-based powered hull on the same tick/snapshot/retune contract as `VehicleDynamics`. */
export interface BoatDynamics {
    tick(dt: number, input: AxisInput): BoatStep;
    pose(): {
        position: readonly [number, number, number];
        heading: number;
    };
    velocity(): readonly [number, number];
    applyImpulse(dvx: number, dvz: number): void;
    retune(next: BoatTuning): void;
    tuning(): BoatTuning;
    snapshot(): BoatState;
    restore(state: BoatState): void;
    resetTo(position: readonly [number, number, number], heading: number): void;
}
/**
 * Creates a {@link BoatDynamics}: throttle drives the prop, brake reverses it, steer swings the rudder or outboard.
 * A rudder boat barely turns at rest unless the prop is washing over it; an outboard turns at rest because it swings
 * the thrust itself. Deterministic for a given `dt` sequence.
 * @capability boat-dynamics force-based powered hull — hull-speed drag hump, planing, keel, rudder that needs flow or outboard thrust
 */
export declare function createBoatDynamics(initial: BoatTuning, options?: BoatOptions): BoatDynamics;