import { MetalFxInstance, ShaderRGB } from './core';
export declare function ensureGlowPixels(): void;
export declare function sampleShaderLumAt(inst: MetalFxInstance, cssPxX: number, cssPxY: number, radius: number): number;
export declare function sampleShaderRGBAt(inst: MetalFxInstance, cssPxX: number, cssPxY: number, radius: number): ShaderRGB;
export declare function sampleShaderRGBChromatic(inst: MetalFxInstance, cssPxX: number, cssPxY: number, radius: number): ShaderRGB;
declare const _pk: {
    r: number;
    g: number;
    b: number;
    lum: number;
};
/** Brightest pixel in the window (not the mean) — for "is the ring shining
 *  here" questions, where a dark stripe next to a bright one should still
 *  read as lit. */
export declare function sampleShaderPeakAt(inst: MetalFxInstance, cssPxX: number, cssPxY: number, radius: number): typeof _pk;
export {};