import type { vec3 } from '@predy-js/render-interface';
import type { ParticleShape } from '@predy-js/specification';
export interface IShape {
    generate(opt: ShapeGeneratorOptions): ShapeParticle;
}
export type ShapeParticle = {
    direction: number[];
    position: number[];
};
export type ShapeGeneratorOptions = {
    total: number;
    index: number;
    burstIndex: number;
    burstCount: number;
};
export type ShapeGenerator = IShape & {
    reverseDirection?: boolean;
    alignSpeedDirection?: boolean;
    upDirection?: vec3;
};
export declare const PI2: number;
export declare function createShape(arg: ParticleShape): IShape;