import type { TSLFloatNode, TSLFunction } from '../types/tsl.js';
/** Float node or numeric literal accepted by the Fresnel curve controls. */
export type FresnelScalarInput = TSLFloatNode | number;
/** Optional curve controls accepted by {@link fresnel}. */
export type FresnelArguments = [power?: FresnelScalarInput, falloff?: FresnelScalarInput];
/**
 * Fresnel effect TSL function.
 * Computes a view-dependent falloff based on the angle between surface normal and view direction.
 *
 * ```js
 * import * as THREE from 'three/webgpu';
 * import { float, color } from 'three/tsl';
 * import { fresnel } from 'three-blocks';
 *
 * const material = new THREE.MeshStandardNodeMaterial({color: 0x111111});
 *
 * const rim = fresnel(float(3.5), float(0.9));
 * const rimCol = color('#F5B700');
 * material.emissiveNode = rimCol.mul(rim);
 * ```
 *
 * @demo docs/demos/fresnel.html
 * @short TSL Fresnel falloff factor based on view angle, useful for rim lighting and edge highlights.
 * @category TSL
 * @tags WebGPU, WebGL
 * @tsl
 * @function fresnel
 * @param {Node.<float>} [power=2.2] - Exponent controlling the falloff curve
 * @param {Node.<float>} [falloff=1.5] - Smoothstep range for the effect
 * @return {Node.<float>} Fresnel factor [0..1]
 */
declare const fresnel: TSLFunction<FresnelArguments, TSLFloatNode>;
export { fresnel };