import Texture2D from '../Texture2D';
import TextureCube from '../TextureCube';
import type Renderer from '../Renderer';
interface LoadTextureOpts {
    fileType?: string;
    exposure?: number;
}
type TextureOnload = (texture: Texture2D) => void;
type TextureOnerror = (err: any) => void;
/**
 * Load texture and return promise.
 */
export declare function loadTexture(path: string, option?: LoadTextureOpts): Promise<Texture2D>;
/**
 * Load and return the texture instance immediately.
 */
export declare function loadTextureSync(path: string, onload?: TextureOnload, onerror?: TextureOnerror): Texture2D;
export declare function loadTextureSync(path: string, option?: LoadTextureOpts, onload?: TextureOnload, onerror?: TextureOnerror): Texture2D;
interface LoadPanoramaOpts extends LoadTextureOpts {
    encodeRGBM?: boolean;
    flipY?: boolean;
}
/**
 * Load a panorama texture and render it to a cube map
 */
export declare function loadPanorama(renderer: Renderer, path: string, cubeMap: TextureCube, option?: LoadPanoramaOpts): Promise<TextureCube>;
/**
 * Render a panorama texture to a cube map
 */
export declare function panoramaToCubeMap(renderer: Renderer, panoramaMap: Texture2D, cubeMap: TextureCube, option?: {
    encodeRGBM?: boolean;
}): TextureCube;
/**
 * Convert height map to normal map
 * @param {HTMLImageElement|HTMLCanvasElement} image
 * @param {boolean} [checkBump=false]
 * @return {HTMLCanvasElement}
 */
export declare function heightToNormal(image: HTMLImageElement | HTMLCanvasElement, checkBump?: boolean): HTMLCanvasElement | HTMLImageElement;
/**
 * Convert height map to normal map
 * @param {HTMLImageElement|HTMLCanvasElement} image
 * @param {boolean} [checkBump=false]
 * @param {number} [threshold=20]
 * @return {HTMLCanvasElement}
 */
export declare function isHeightImage(img: HTMLImageElement | HTMLCanvasElement, downScaleSize: number, threshold: number): boolean;
/**
 * Create a chessboard texture
 * @param  {number} [size]
 * @param  {number} [unitSize]
 * @param  {string} [color1]
 * @param  {string} [color2]
 * @return {clay.Texture2D}
 */
export declare function createChessboard(size: number, unitSize: number, color1: string, color2: string): Texture2D;
/**
 * Create a blank pure color 1x1 texture
 * @param  {string} color
 * @return {clay.Texture2D}
 */
export declare function createBlank(color: string): Texture2D;
export {};