unibutton/js/index.js

const cs = 1024;
const assets = [
    'assets/player.svg',
    'assets/head.svg',
];

function Game() {
    let assetsIn = {};

    for (let asset in assets) {
        assetsIn[asset] = new Image();
        assetsIn[asset].src = assets[asset];
    }

    let canvas = document.querySelector("#canvas");
    let player = new Player();
    let entities = [player];

    for (let i = 0; i < 15; i++) {
        entities.push(new Player())
    }

    canvas.width = canvas.height = cs;

    this.canvas = canvas;
    this.ctx = canvas.getContext("2d");
    this.ticks = 1;
    this.assetsIn = assetsIn;
    this.player = player;
    this.entities = entities;
}

Game.prototype.main = function () {
    let { entities } = this;

    this.ticks++;

    for (let player of entities) {
        player.pos.x += player.vel.x;
        player.pos.y += player.vel.y;

        player.vel.x *= 0.8;
        player.vel.y *= 0.8;

        player.rot += 0.03 * player.dir;
        player.rot = player.rot % (Math.PI * 10);

        player.camera.x = -player.pos.x * 0.1 + player.camera.x * 0.9;
        player.camera.y = -player.pos.y * 0.1 + player.camera.y * 0.9;
    }
}

// todo: move into its own file
Game.prototype.render = function () {
    let { ctx, assetsIn, entities, player } = this;

    ctx.clearRect(0, 0, cs, cs);

    ctx.save();

    ctx.translate(player.camera.x + cs / 2, player.camera.y + cs / 2);

    for (let ent of entities) {
        ctx.save();

        ctx.translate(ent.pos.x, ent.pos.y);
        ctx.rotate(ent.rot);
        ctx.drawImage(assetsIn[1], -64 / 2, -128, 64, 128);

        ctx.restore();

        ctx.drawImage(assetsIn[0], ent.pos.x - 64 / 2, ent.pos.y - 64 / 2, 64, 64);
    }

    ctx.restore();
}

Game.prototype.click = function () {
    let { player } = this;

    if (this.ticks < 10) {
        player.dir *= -1;
    }

    player.vel.x *= 0.6;
    player.vel.y *= 0.6;

    player.vel.x += Math.sin(player.rot) * 25;
    player.vel.y -= Math.cos(player.rot) * 25;

    this.ticks = 0;
}

var game = new Game();

setInterval(function () { game.main() }, 1000 / 60);
setInterval(function () { game.render() }, 1000 / 60);

game.canvas.onclick = () => game.click();