/**
 * splat-shared-sort.parity.ts
 *
 * JavaScript port of the WGSL kernel in `splat-shared-sort.wgsl`. Exists so
 * the kernel can be exercised in Node test harnesses (no WebGPU adapter
 * available there) and compared bit-for-bit against the CPU reference at
 * `packages/core/src/traits/MultiviewGaussianRendererTrait.ts::preprocess()`.
 *
 * Invariants (each enforced by tests):
 *   1. For ANY input fixture (positions + view eye/direction tuples), this
 *      parity twin MUST produce the same `visibilityBitmasks` array as
 *      MultiviewGaussianRendererTrait.preprocess() — bit-exact, not approximate.
 *   2. Distance keys (squared distance to centroid) MUST agree within f32
 *      tolerance when sorted descending — the back-to-front order must match.
 *   3. The cone-test threshold `DEFAULT_HALF_FOV_COS` MUST equal the CPU ref's
 *      constant of the same name (currently 0.5 = cos(60deg) half-FOV).
 *
 * If the .wgsl file is edited, this parity twin MUST be updated in lockstep.
 * The test suite catches divergence: a structural regex check confirms the
 * .wgsl file contains the load-bearing operations (toGLen2, inverseSqrt,
 * safeNormalize, DEFAULT_HALF_FOV_COS); the behavioral tests confirm the JS
 * port matches the CPU reference.
 *
 * @see splat-shared-sort.wgsl
 * @see packages/core/src/traits/MultiviewGaussianRendererTrait.ts
 */
/** Half-FOV cosine threshold — MUST match WGSL constant + CPU ref. */
export declare const DEFAULT_HALF_FOV_COS = 0.5;
/** Max view count encodable in the uint32 bitmask. */
export declare const MAX_BITMASK_VIEWS = 32;
export interface ParityViewConfig {
    /** [x, y, z] world-space eye position. */
    eyePosition: [number, number, number];
    /** [x, y, z] eye look direction — need not be unit-length (safeNormalized internally). */
    eyeDirection: [number, number, number];
}
export interface ParityResult {
    /** Per-Gaussian squared distance to the shared centroid (sort key). */
    distances: Float32Array;
    /** Per-Gaussian uint32 visibility bitmask: bit v set ⇒ Gaussian visible in views[v]. */
    visibilityBitmasks: Uint32Array;
    /** Back-to-front sorted Gaussian indices (descending by distance). */
    sortedIndices: Uint32Array;
}
/**
 * Pure-JS twin of the WGSL `cs_preprocess` kernel.
 *
 * @param positions Flat [x0,y0,z0, x1,y1,z1, …] array of Gaussian positions (length 3*N).
 * @param views     Array of view configs. Order matters — bit v in the bitmask refers to views[v].
 * @returns Object containing distances, visibilityBitmasks, and back-to-front sortedIndices.
 */
export declare function preprocessSharedSort(positions: Float32Array | readonly number[], views: readonly ParityViewConfig[]): ParityResult;
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