/** Three-dimensional acceleration vector sampled from a gravity field. */
export type GravityVector = readonly [number, number, number];
/** Position-dependent gravity source used by movement and vehicle simulations. */
export interface GravityField {
    sample(position: GravityVector): GravityVector;
}
/** Center, strength, and falloff for radial gravity. */
export interface PointGravityOptions {
    center: GravityVector;
    strength: number;
    falloff?: "constant" | "inverseSquare";
    minRadius?: number;
}
/** Constant vector gravity for ordinary worlds, space stations, and sideways-gravity levels.
 * @capability gravity-field sample configurable uniform, radial, or combined gravity
 */
export declare function uniformGravity(vector?: GravityVector): GravityField;
/** Radial gravity toward one center, with optional inverse-square falloff for planetary worlds.
 * @capability gravity-field sample configurable uniform, radial, or combined gravity
 */
export declare function pointGravity(options: PointGravityOptions): GravityField;
/** Adds several gravity sources into one field.
 * @capability gravity-field sample configurable uniform, radial, or combined gravity
 */
export declare function combineGravity(fields: readonly GravityField[]): GravityField;