export declare class UnitSphereSampling {
    private static readonly ALMOST_ONE;
    private readonly _nbits;
    private _npoint;
    private _mindex;
    private _nindex;
    private _m;
    private _n;
    private _d;
    private _od;
    private _pu;
    private _pl;
    private _ip;
    constructor(nbits?: number);
    get countSamples(): number;
    get maxIndex(): number;
    private _init;
    /**
     * Gets an array { ia, ib, ic } of three sample indices for the spherical
     * triangle that contains the specified point.
     * <p>
     * As viewed from outside the sphere, the sampled points corresponding to
     * the returned indices are ordered counter-clockwise.
     * @param array array { x, y, z } of point coordinates.
     * @returns array of sample indices.
     */
    getTriangle(array: number[]): number[];
    /**
     * Gets an array { ia, ib, ic } of three sample indices for the spherical
     * triangle that contains the specified point.
     * <p>
     * As viewed from outside the sphere, the sampled points corresponding to
     * the returned indices are ordered counter-clockwise.
     * @param x x-coordinate of the point.
     * @param y y-coordinate of the point.
     * @param z z-coordinate of the point.
     * @returns array of sample indices.
     */
    getTriangle(x: number, y: number, z: number): number[];
    /**
     * Gets an array { wa, wb, wc } of three weights for a point in a spherical
     * triangle specified by sample indices of three points.
     * <p>
     * The weights are proportional to volumes of tetrahedra, and are used for
     * interpolation. Weights are non-negative and normalized so that their
     * sum wa + wb + wc = 1.
     * <p>
     * For example, let p denote the specified point with coordinates { x, y, z },
     * and let o denote the center of the sphere with coordinates { 0, 0, 0 }.
     * Then the weight wa is proportional to the volume of the tetrahedron
     * formed by points p, b, c, and o.
     * @param array an array { x, y, z } containing point coordinates.
     * @param iabc array { ia, ib, ic } of sample indices.
     * @returns array { wa, wb, wc } of weights.
     */
    getWeights(array: number[], iabc: number[]): number[];
    /**
     * Gets an array { wa, wb, wc } of three weights for a point in a spherical
     * triangle specified by sample indices of three points.
     * <p>
     * The weights are proportional to volumes of tetrahedra, and are used for
     * interpolation. Weights are non-negative and normalized so that their
     * sum wa + wb + wc = 1.
     * <p>
     * For example, let p denote the specified point with coordinates { x, y, z },
     * and let o denote the center of the sphere with coordinates { 0, 0, 0 }.
     * Then the weight wa is proportional to the volume of the tetrahedron
     * formed by points p, b, c, and o.
     * @param x x-coordinate of the point.
     * @param y y-coordinate of the point.
     * @param z z-coordinate of the point.
     * @param iabc array { ia, ib, ic } of sample indices.
     * @returns array { wa, wb, wc } of weights.
     */
    getWeights(x: number, y: number, z: number, iabc: number[]): number[];
    /**
     * Gets the index of the sampled point nearest to the specified point.
     * <p>
     * Here, the nearest sampled point is that nearest on the octahedron.
     * Returns a positive index for points in the upper hemisphere (z &gt;= 0),
     * including points on the equator (z = 0). Returns a negative index for
     * points in the lower hemisphere not on the equator (z &lt; 0).
     * @param array an array of coordinates.
     * @returns the sample index.
     */
    getIndex(array: number[]): number;
    /**
     * Gets the index of the sampled point nearest to the specified point.
     * @param x x-coordinate of the point.
     * @param y y-coordinate of the point.
     * @param z z-coordinate of the point.
     * @returns the sample index.
     */
    getIndex(x: number, y: number, z: number): number;
    /**
     * Gets the sampled point for the specified index, which must be non-zero.
     * <p>
     * For efficiency, returns the array { x, y, z } of point coordinates
     * by reference, not by copy. These coordinates must not be modified.
     * @param index the index of the sampled point; must be non-zero.
     * @returns array { x, y, z } of point coordinates; by reference, not by copy.
     */
    getPoint(index: number): number[];
}