import { vec2 } from "gl-matrix";
import Circle from "../../shapes/circle";
import Texture from "../../texture/texture";
import Color from "../../utils/color";
import Physics from "../physics";
import kdTree from "./kdTree";
import Particle from "./particle";
export declare const MAX_FLUID_PARTICLES = 1000;
export interface FluidOptions {
    restDensity: number;
    smoothingRadius: number;
    stiffness: number;
    stiffnessNear: number;
    particleRadius: number;
    maxParticles: number;
    collisionGroup: number;
    color?: Color;
    zIndex?: number;
    renderThreshold?: number;
    debug?: boolean;
    debugTex?: Texture;
}
/**
 * Simulates a fluid using SPH (Smooth Particle Hydrodynamics).
 *
 * @see [SPH Fluid Sim in Processing](https://hmbd.wordpress.com/2019/06/10/sph-fluid-simulation-in-processing/)
 * @see [Processing Code](https://github.com/DanielsSim/hmbd/blob/master/Processing/SPH/Fluid.pde)
 * @see [Particle-based Viscoelastic Fluid Sim](http://www.ligum.umontreal.ca/Clavet-2005-PVFS/pvfs.pdf)
 */
export default class Fluid {
    particles: Particle[];
    restDensity: number;
    smoothingRadius: number;
    smoothingRadiusSqr: number;
    stiffness: number;
    stiffnessNear: number;
    particleRadius: number;
    maxParticles: number;
    collisionGroup: number;
    kdTree: kdTree;
    color: Color;
    renderThreshold: number;
    /**
     * The z layer of the fluid.
     */
    zIndex: number;
    debug: boolean;
    debugTex: Texture;
    debugShapes: Map<Particle, Circle>;
    /**
     * The physics world the fluid sim was added to.
     */
    physics: Physics;
    /**
     * Creates an {@link Fluid} with the given options.
     *
     * @param opts The options to setup the fluid with
     */
    constructor(opts: FluidOptions);
    /**
     * Adds a particle to the fluid at the given position.
     *
     * @param pos The position to create the particle at in world space.
     * @returns Wether or not the particle was added
     */
    addParticle(pos: vec2): boolean;
    /**
     * Steps the fluid simulation forward in time.
     *
     * @param delta The time since the last update
     */
    update(delta: number): void;
    private translate;
    /**
     * Integrate any forces on the particle, including gravity, and integrate velocity.
     *
     * Also resets the particle's density from the last update.
     *
     * @param delta The time since the last update
     */
    integrate(delta: number, gravity: vec2): void;
    /**
     * Queues the fluid to be renderer using the fluid renderer.
     */
    render(): void;
    /**
     * Renders the particles of the fluid as individual circles.
     */
    debugRender(): void;
}