import type { TSLFloatNode, TSLFunction, TSLTextureInput, TSLVec3Node, TSLVec4Node } from '../types/tsl.js';
/** Float node or numeric literal accepted by biplanar mapping controls. */
export type BiplanarFloatInput = TSLFloatNode | number;
/** Arguments accepted by {@link biplanarTexture}. */
export type BiplanarTextureArguments = [
    textureX: TSLTextureInput,
    textureY?: TSLTextureInput | null,
    textureZ?: TSLTextureInput | null,
    scale?: BiplanarFloatInput,
    position?: TSLVec3Node,
    normal?: TSLVec3Node,
    hardness?: BiplanarFloatInput
];
/**
 * Efficient biplanar texture mapping for world-space triplanar-style effects.
 * Samples only the two most dominant axis projections and blends them,
 * reducing texture fetches compared to full triplanar mapping.
 *
 * **Algorithm**
 * - Determines the two dominant axes based on surface normal
 * - Projects position onto corresponding planes (XY, YZ, ZX)
 * - Samples textures with proper derivatives for mipmapping
 * - Blends samples using weighted power curve for smooth transitions
 *
 * **Benefits**
 * - 33% fewer texture samples than triplanar (2 vs 3)
 * - Avoids visible seams on axis-aligned surfaces
 * - Supports per-axis texture variation
 * - Automatic mipmap derivatives via `grad()`
 *
 * ```js
 * import { biplanarTexture } from 'three-blocks';
 * import { texture, float } from 'three/tsl';
 *
 * const diffuseTex = texture(diffuseMap);
 * const normalTex = texture(normalMap);
 *
 * // Same texture on all axes with 2x tiling
 * material.colorNode = biplanarTexture(diffuseTex, null, null, float(2));
 *
 * // Different textures per axis
 * material.colorNode = biplanarTexture(
 *   texture(texX),  // YZ plane
 *   texture(texY),  // ZX plane
 *   texture(texZ),  // XY plane
 *   float(1),       // scale
 *   positionLocal,  // position
 *   normalLocal,    // normal
 *   float(8)        // blend hardness
 * );
 * ```
 *
 * @function biplanarTexture
 * @short Biplanar world-space mapping that blends the two dominant axes for triplanar-like results with fewer samples.
 * @category TSL
 * @tsl
 * @tags WebGPU, WebGL
 * @param {Node} textureXNode Texture sampled on YZ plane (X-axis projection).
 * @param {Node} [textureYNode=textureXNode] Texture sampled on ZX plane (Y-axis projection).
 * @param {Node} [textureZNode=textureXNode] Texture sampled on XY plane (Z-axis projection).
 * @param {Node.<float>} [scaleNode=1] UV coordinate scale multiplier.
 * @param {Node.<vec3>} [positionNode=positionLocal] Fragment position for UV projection.
 * @param {Node.<vec3>} [normalNode=normalLocal] Surface normal for axis weight calculation.
 * @param {Node.<float>} [hardnessNode=8] Blend sharpness (higher = sharper transitions).
 * @returns {Node.<vec4>} Blended texture color (RGBA).
 */
export declare const biplanarTexture: TSLFunction<BiplanarTextureArguments, TSLVec4Node>;