import type { MaterialDiagnostic } from "./materialAsset.js";
/** Tangents follow card width (UV U); strand length follows UV V. Angles are radians. */
export declare const HAIR_CARD_STRAND_ROTATION: number;
/** An authored centreline, in model-local metres, with root-to-tip points. */
export interface HairCardGuide {
    id: string;
    points: readonly (readonly [number, number, number])[];
    width: number;
    tipWidth?: number;
    /** Desired front-facing normal; must not be parallel to the strand direction. */
    facing: readonly [number, number, number];
    /** Atlas rectangle [uMin,vMin,uMax,vMax]; U is width and V is root to tip. */
    uvRect?: readonly [number, number, number, number];
}
/** Serializable geometry authoring, independent of materials, grooming physics and collisions. */
export interface HairCardAuthoring {
    guides: readonly HairCardGuide[];
    subdivisionsPerSegment?: number;
    /** Allocation ceiling for offline/editor generation; default 65,536 vertices. */
    maxVertices?: number;
}
/** Renderer-neutral indexed ribbons with an explicit tangent frame and guide ranges. */
export interface HairCardMesh {
    positions: number[];
    normals: number[];
    tangents: number[];
    uvs: number[];
    indices: number[];
    bounds: {
        min: [number, number, number];
        max: [number, number, number];
    };
    guides: {
        id: string;
        vertexStart: number;
        vertexCount: number;
        indexStart: number;
        indexCount: number;
    }[];
}
/**
 * Validate finite guides, tangent frames and bounded generation; crossing/collision is not solved.
 * @capability hair-card-geometry validate authored ribbon guides and their vertex allocation ceiling
 */
export declare function validateHairCardAuthoring(value: unknown): MaterialDiagnostic[];
/** Build deterministic model-local ribbon geometry; guides remain separately editable source data. */
export declare function buildHairCards(input: HairCardAuthoring): HairCardMesh;