import type { HomogeneousProjection, HomogeneousProjectionPointN, ProjectionFibreN } from './types.js';
export interface PerspectiveProjectionOptions {
    fromDim: number;
    /**
     * Distance from the projection viewpoint to the origin along each hidden
     * axis. Points at hidden coordinate 0 project at unit scale; points
     * nearer the viewpoint appear larger. Default 2.
     */
    viewDistance?: number;
    /** Denominator clamp guarding the perspective divide. Default 1e-6. */
    epsilon?: number;
}
/**
 * Iterated perspective projection ℝⁿ → ℝ³.
 *
 * Projects one dimension at a time (n → n−1 → … → 3): at each step the
 * highest remaining coordinate x_d becomes a depth, scaling the surviving
 * coordinates by viewDistance / (viewDistance − x_d). For n = 4 this is the
 * classic "tesseract" perspective; for n = 3 it is the identity.
 *
 * Points at or behind the viewpoint (x_d ≥ viewDistance) are clamped, not
 * clipped — geometry that crosses the viewpoint will distort. Proper 4D
 * frustum clipping is a planned, separate stage.
 */
export declare class PerspectiveProjection implements HomogeneousProjection {
    readonly fromDim: number;
    viewDistance: number;
    epsilon: number;
    constructor({ fromDim, viewDistance, epsilon }: PerspectiveProjectionOptions);
    projectPoint(p: ArrayLike<number>): [number, number, number];
    projectPositions(src: Float64Array, count: number, dst: Float32Array): void;
    /**
     * Row-major matrix for the unclamped projective chain.
     *
     * With one shared view distance the final denominator is
     * `q = 1 - sum(hiddenCoordinates) / viewDistance`. The validity report,
     * rather than final `q` alone, determines whether every intermediate divide
     * stays on this projective branch.
     */
    homogeneousMatrix(): Float64Array;
    projectHomogeneousPoint(point: ArrayLike<number>): HomogeneousProjectionPointN;
    projectHomogeneousPositions(src: Float64Array, count: number, dst: Float64Array, validity?: Uint8Array): void;
    /**
     * Exact affine fibre of the unclamped projective matrix, intersected with
     * the open validity half-space contributed by every perspective stage.
     */
    inverseFibre(point: ArrayLike<number>): ProjectionFibreN;
    private assertConfiguration;
}
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