import * as THREE from 'three';
import type { Disposable } from '../types.js';
/** Two-color vertical gradient for the procedural sky dome. */
export interface GradientSkyOptions {
    top: THREE.ColorRepresentation;
    bottom: THREE.ColorRepresentation;
    /** Curve of the blend: 1 = linear, >1 pushes the horizon color up. Default 1.5. */
    exponent?: number;
}
/** Options for {@link createSkybox} — set exactly one of `color`, `gradient`, `equirect`, or `cube`. */
export interface SkyboxOptions {
    /** Flat background color. */
    color?: THREE.ColorRepresentation;
    /** Procedural vertical-gradient dome. */
    gradient?: GradientSkyOptions;
    /** Equirectangular panorama — a texture, or a URL (DOM only). */
    equirect?: THREE.Texture | string;
    /** Cube map — a CubeTexture, or six face URLs +x,-x,+y,-y,+z,-z (DOM only). */
    cube?: THREE.CubeTexture | string[];
    /** Also assign the texture as scene.environment for IBL. Default false. */
    environment?: boolean;
    /** Gradient dome radius. Keep inside the camera far plane. Default 400. */
    radius?: number;
}
/** Handle returned by {@link createSkybox}. `dispose()` frees owned textures/meshes and restores the scene's previous background and environment. */
export interface Skybox extends Disposable {
    /** The gradient dome mesh, when the gradient mode is active. */
    object: THREE.Object3D | null;
}
/**
 * Set the scene background: a flat color, a procedural vertical-gradient
 * dome, an equirectangular panorama, or a cube map — optionally assigning the
 * texture as `scene.environment` for image-based lighting.
 *
 * @param scene - Scene whose background (and optionally environment) is set.
 * @param options - The sky mode plus `environment` and dome `radius`.
 * @returns A {@link Skybox}; `object` is the gradient dome mesh when that
 * mode is active.
 * @remarks The gradient dome renders at the far plane so it never occludes
 * content, and is GL-free to construct (safe headless). URL-based `equirect`
 * and `cube` sources need a DOM.
 * @example
 * const sky = createSkybox(scene, { gradient: { top: '#79f7ff', bottom: '#0a0a14' } })
 */
export declare function createSkybox(scene: THREE.Scene, { color, gradient, equirect, cube, environment, radius, }: SkyboxOptions): Skybox;
//# sourceMappingURL=skybox.d.ts.map