Varley

A multiplayer game engine with rapid prototyping as its sole focus. Intended to be used for game jams with limited time, such as the 1 hour game jam.

Features

• Multiplayer.
• Top down and platformer movement, including collisions.
• Animations, sprite sheets.
• Matchmaking, lobby: you can start games with a minimum and maximum number of players, and there can be multiple games running at the same time.
• Game state diffing: only the data that has been modified is sent every network tick, not the entire game state.
• Chat module available.

Examples

Try playing with a friend!

• Tron-like game
• Farm game
• Platformer game

The source code of these 3 games is available in the examples folder.

Documentation

There's a wiki available.

Quick Start

To start a new Varley project, simply create a new directory, then run npm init -f and npm install varley --save inside of it.

Afterwards, pick an example from above, and copy the files from the examples folder of this repository.

Then, use node server.js to run your game.

You can then play it at http://localhost:8080!

Code Example

To see how short games can be, an example of a tron-like game is available below.

server.js:

const varley = require('varley')(this);

varley.on('start', () => {
  varley.pub.world = Array(WORLD_WIDTH * WORLD_HEIGHT).fill(-1)
})

varley.on('connect', player => {
  player.vx = 1, player.vy = 0
  player.x = Math.floor(Math.random() * WORLD_WIDTH)
  player.y = Math.floor(Math.random() * WORLD_HEIGHT)
})

let keys = {'UP': [0, -1], 'LEFT': [-1, 0], 'RIGHT': [1, 0], 'DOWN': [0, 1]}
varley.on('press', (player, key) =>
  [player.vx, player.vy] = keys[key] || [player.vx, player.vy])

varley.on('playertick', player => {
  player.x = player.x + player.vx, player.y = player.y + player.vy

  if(player.x < 0 || player.y < 0 ||
     player.x >= WORLD_WIDTH || player.y >= WORLD_HEIGHT ||
     varley.pub.world[player.x + player.y * WORLD_WIDTH] !== -1)
    return player.disconnect()

  varley.pub.world[player.x + player.y * WORLD_WIDTH] = player.id
})

varley.on('disconnect', player =>
  varley.pub.world = varley.pub.world.map(t => t == player.id ? -1 : t))

varley.run()

client.js:

const SIZE = [1000, 700]
const BLOCK_SIZE = SIZE[0] / WORLD_WIDTH

const PAGE_BG = '#FFFFFF'
const CANVAS_BG = 'green'

const colors = ['#FF0000', '#00FF00', '#0000FF',
                '#FFFF00', '#FF00FF', '#00FFFF']

function update() {
  for(let y = 0; y < WORLD_HEIGHT; ++y)
  for(let x = 0; x < WORLD_WIDTH; ++x) {
    let color = pub.world[x + y * WORLD_WIDTH] % 6
    const BS = BLOCK_SIZE
    drawRect(x * BS, y * BS, BS, BS, colors[color])
  }
}

shared.js:

const WORLD_WIDTH = 50, WORLD_HEIGHT = 35

Contributing

The best way to contribute at this point is to try out the engine, and e-mail ([email protected]) me your thoughts on it, or create an issue if you find a problem with it. Pull requests are also welcome, if you fix the problem you've found.

If you have a feature request, feel free to open an issue, so that we can discuss it.