README.md

BounceJS - Bouncy Balls with JavaScript

A 2D, circles-only physics engine for adding interactive balls to a webpage. Check out this demo

Usage

BounceJS draws on an html canvas, so the first thing you will want to do is place a canvas wherever it is that you want bouncyballs.

<canvas id="bouncejs-canvas"></canvas>

Now you can pass that canvas to an instance of the Engine class along with the background color. Notice that the width and height are defined manually. This is necessary for the engine to pick up the width and height.

import { Engine } from './bouncejs/Engine.js';

const canvas = document.getElementById('bouncejs-canvas');
canvas.width = 500;
canvas.height = 500;

const engine = new Engine(canvas, 'white');

Now that the engine is instantiated, you can add balls to it and start it.

import { Engine } from './bouncejs/Engine.js';
import { Ball } from './bouncejs/Ball.js';

const canvas = document.getElementById('bouncejs-canvas');
canvas.width = 500;
canvas.height = 500;

const engine = new Engine(canvas, 'white');

const smallFastRedBall = new Ball();
ball.radius = 50;
ball.color = 'red';
ball.position.x = Math.random() * canvas.width; // Random position
ball.position.y = Math.random() * canvas.height;
ball.velocity.x = 150; // The unit for velocity is pixels/second
ball.velocity.y = 150;
engine.add(smallFastRedBall);

const bigSlowBlueBall = new Ball();
ball.radius = 150;
ball.color = 'blue';
ball.position.x = Math.random() * canvas.width; // Random position
ball.position.y = Math.random() * canvas.height;
ball.velocity.x = 50; // The unit for velocity is pixels/second
ball.velocity.y = 50;
engine.add(bigSlowBlueBall);

engine.start(); // Start the engine

The canvas you put on your page should now have 2 balls bouncing around inside.