import { Nullable, PropertyType } from '../constants';
import type { Accessor } from './accessor';
import type { IExtensibleProperty } from './extensible-property';
import { Property } from './property';
interface IPrimitiveTarget extends IExtensibleProperty {
    attributes: {
        [key: string]: Accessor;
    };
}
/**
 * # PrimitiveTarget
 *
 * *Morph target or shape key used to deform one {@link Primitive} in a {@link Mesh}.*
 *
 * A PrimitiveTarget contains a `POSITION` attribute (and optionally `NORMAL` and `TANGENT`) that
 * can additively deform the base attributes on a {@link Mesh} {@link Primitive}. Vertex values
 * of `0, 0, 0` in the target will have no effect, whereas a value of `0, 1, 0` would offset that
 * vertex in the base geometry by y+=1. Morph targets can be fully or partially applied: their
 * default state is controlled by {@link Mesh.getWeights}, which can also be overridden for a
 * particular instantiation of a {@link Mesh}, using {@link Node.getWeights}.
 *
 * Reference:
 * - [glTF → Morph Targets](https://github.com/KhronosGroup/gltf/blob/main/specification/2.0/README.md#morph-targets)
 */
export declare class PrimitiveTarget extends Property<IPrimitiveTarget> {
    propertyType: PropertyType.PRIMITIVE_TARGET;
    protected init(): void;
    protected getDefaults(): Nullable<IPrimitiveTarget>;
    /** Returns a morph target vertex attribute as an {@link Accessor}. */
    getAttribute(semantic: string): Accessor | null;
    /**
     * Sets a morph target vertex attribute to an {@link Accessor}.
     */
    setAttribute(semantic: string, accessor: Accessor | null): this;
    /**
     * Lists all morph target vertex attribute {@link Accessor}s associated. Order will be
     * consistent with the order returned by {@link .listSemantics}().
     */
    listAttributes(): Accessor[];
    /**
     * Lists all morph target vertex attribute semantics associated. Order will be
     * consistent with the order returned by {@link .listAttributes}().
     */
    listSemantics(): string[];
}
export {};