import type { Texture } from "@vgpu/core";
export interface PixelDiffResult {
    /** Largest absolute per-byte difference (0–255). The headline: ≤1–2 is driver-rounding noise. */
    readonly maxByte: number;
    /** Mean absolute per-byte difference. */
    readonly meanByte: number;
    /** Bytes that differ at all. */
    readonly changedBytes: number;
    readonly totalBytes: number;
    /** changedBytes / totalBytes. A tiny fraction with maxByte ≤ ~2 means "imperceptible". */
    readonly changedFraction: number;
}
/**
 * Compares two renders byte-for-byte — the verify half of measure-before-keeping. Pass two
 * `Texture`s (read back via {@link Texture.read}) or two already-read `Uint8Array`s. Use it to
 * confirm an optimization is bit-exact (maxByte 0) or imperceptible (maxByte ≤ ~2 on a small
 * fraction) before keeping it.
 *
 * @example
 * const before = await renderInto(target);      // baseline texture
 * applyOptimization();
 * const after = await renderInto(target);
 * const { maxByte } = await pixelDiff(before, after);
 * expect(maxByte).toBeLessThanOrEqual(2);
 */
export declare function pixelDiff(a: Texture | Uint8Array, b: Texture | Uint8Array): Promise<PixelDiffResult>;
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