@gravity-simulator/gravity-resolver

Gravity Resolver

Provides two classes for performing gravity calculations in 2D.

Gravity Resolver

Given an array of bodies, parallelly performs gravity calculations between all bodies on GPU, and returns the array of bodies with updated position and velocity vectors

Barnes Hut Tree Resolver

Given an array of bodies and a quadtree of nodes with references to the bodies, parallelly performs gravity calculation approximation via the barnes hut algorithm, and returns the array of bodies with updated position and velocity vectors

Installation

npm install @gravity-simulator/gravity-resolver

Usage

Bodies should provide the following properties:

• mass: number
• positionX: number
• positionY: number
• velocityX: number
• velocityY: number

Example usage - Gravity Resolver

const GravityResolver = require('@gravity-simulator/gravity-resolver').GravityResolver;

const resolver = new GravityResolver();

const bodies = [{mass: 100, positionX: 40, positionY: 120, velocityX: 0, velocityY: 0},
                {mass: 200, positionX: 80, positionY: 120, velocityX: 0, velocityY: 0},
                {mass: 50, positionX: 160, positionY: 40, velocityX: 0, velocityY: 0},
                {mass: 100, positionX: 160, positionY: 160, velocityX: 0, velocityY: 0}];

resolver.resolveNewPositions(bodies);

console.log(bodies) 
==> [
        {
            mass: 100,
            positionX: 40.132930755615234,
            positionY: 120.00064086914062,
            velocityX: 0.13292938470840454,
            velocityY: 0.00064300955273211
        },
        {
            mass: 200,
            positionX: 79.9514389038086,
            positionY: 120.0028305053711,
            velocityX: -0.048557523638010025,
            velocityY: 0.0028280343394726515
        },
        {
            mass: 50,
            positionX: 159.98495483398438,
            positionY: 40.020660400390625,
            velocityX: -0.015048785135149956,
            velocityY: 0.02065981552004814
        },
        {
            mass: 100,
            positionX: 159.97171020507812,
            positionY: 159.98336791992188,
            velocityX: -0.028289951384067535,
            velocityY: -0.016628986224532127
        }
    ]

Configuration

Both Resolvers accept an input to the constructor for a gravity constant (default = 1)

Considerations

Gravity Resolver is suitable for smaller numbers of bodies. For larger numbers of bodies, Barnes Hut Tree resolver should offer greater performance. To build the quadtree, use barnes-hut-tree-builder module https://www.npmjs.com/package/barnes-hut-tree-builder, using the buildToArray method.

This project is still in early development and further features for ease of use, as well as more extensive documentation will be coming in later versions.