Using Kaboom.js with Playroom Kit
Kaboom (opens in a new tab) is a Javascript game programming library that helps you make games fast and fun.
Making a Kaboom Game Multiplayer
To make a Kaboom game multiplayer, you can pipe the game state to Playroom state methods and also pipe the player inputs to Playroom.
Here is a simple example with relevant parts highlighted:
import kaboom from "kaboom";
import nipplejs from "nipplejs";
// 0. Import Playroom SDK
import { onPlayerJoin, insertCoin, isHost, myPlayer } from "playroomkit";
const SPEED = 320;
const PLAYERSIZE = 20;
function start() {
kaboom({ width: 300, height: 480, background: [0, 0, 0]});
gravity(1600);
// 1. Pass Joystick data to Playroom SDK
const joystick = nipplejs.create();
joystick.on("plain", (e, data) => {
myPlayer().setState("dir", data.direction);
});
joystick.on("end", () => {
myPlayer().setState("dir", undefined);
});
// Platform to hold the player(s)
add([
rect(width(), 48),
color(0, 255, 0),
pos(0, height() - 48),
area(),
solid(),
]);
// 2. When a new player joins, add a circle for them in the color they chose
onPlayerJoin((player) => {
const playerColor = player.getProfile().color;
const playerSprite = add([
circle(PLAYERSIZE),
color(playerColor.r, playerColor.g, playerColor.b),
pos(rand(0, width()), center().y),
area({ shape: "circle", width: PLAYERSIZE, height: PLAYERSIZE }),
body(),
]);
playerSprite.onUpdate(() => {
// 3. We use host player as the source of truth for player positions
if (isHost()) {
const controls = player.getState("dir") || {};
if (controls.x == "left") {
playerSprite.move(-SPEED, 0);
}
if (controls.x == "right") {
playerSprite.move(SPEED, 0);
}
if (controls.y == "up" && playerSprite.isGrounded()) {
playerSprite.jump();
}
// Sync position to other players
player.setState("pos", {
x: playerSprite.pos.x,
y: playerSprite.pos.y,
});
}
// Other players receive position from host and move player on their screen
else {
const newPos = player.getState("pos") || { x: 0, y: 0 };
playerSprite.moveTo(newPos.x, newPos.y);
}
});
player.onQuit(() => destroy(playerSprite));
});
}
insertCoin().then(start);
Here is a live preview of the above code: