/**
 * UV Raycasting
 *
 * Converts 3D raycast hits to UV pixel coordinates for painting.
 * This is the core of painting directly on 3D models.
 *
 * Implements Blockbench's exact 3D-to-UV painting pipeline:
 * 1. Raycast from mouse into 3D scene
 * 2. Get barycentric coordinates from hit
 * 3. Interpolate UV from triangle vertices
 * 4. Convert UV → pixel coordinates
 * 5. Apply brush to texture
 * 6. Update viewport
 */
import { Texture } from './texture';
import { MeshFace } from '../geometry/mesh_face';
import { Vector3 } from '../modeling/transform';
export interface RaycastHit {
    element: any;
    face: string | number;
    uv?: [number, number];
    point?: Vector3;
    barycentric?: [number, number, number];
    distance?: number;
}
export interface UVPaintCoordinates {
    x: number;
    y: number;
    texture: Texture;
    element: any;
    face: string | number;
    uv: [number, number] | [number, number, number, number];
}
/**
 * Convert raycast UV coordinates to pixel coordinates
 *
 * Implements Blockbench's exact UV → pixel conversion:
 * pixelX = floor(u * textureWidth)
 * pixelY = floor(v * textureHeight)
 *
 * This is used when painting directly on 3D models
 */
export declare function getCanvasToolPixelCoords(uv: [number, number], texture: Texture): [number, number];
/**
 * Convert raycast hit to UV paint coordinates
 *
 * Implements Blockbench's exact 3D-to-UV painting conversion:
 * 1. For cubes: Use parametric UV rectangle
 * 2. For meshes: Use barycentric interpolation
 * 3. Convert UV → pixel coordinates
 */
export declare function raycastHitToPaintCoords(hit: RaycastHit, texture: Texture): UVPaintCoordinates | null;
/**
 * Get texture to edit from element face
 * Handles texture groups and material mode
 */
export declare function getTextureToEdit(texture: Texture | null | undefined, viewMode?: 'material' | 'texture'): Texture | null;
/**
 * Get mesh UV island (connected faces sharing UV space)
 * Framework adapters should implement this based on their mesh structure
 */
export declare function getMeshUVIsland(faceKey: string | number, face: MeshFace, element: any): Array<string | number>;
/**
 * Check if two faces are in the same UV island
 */
export declare function areFacesInSameUVIsland(face1: string | number, face2: string | number, element: any): boolean;
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