mr-crocs-adventures/js/module.js

import RetroSprite from "./retro/RetroSprite.js";
import Key from "./Key.js";
import MrCroc from "./MrCroc.js";

const MEDIA_READY_EVENT = 'mediaready';
const IMAGE_READY_EVENT = 'imgready';

class ImageLoader
{
    images = [];
    numberImagesLoaded = 0;

    update()
    {
        this.numberImagesLoaded++;

        if (this.numberImagesLoaded === this.images.length) {
            window.dispatchEvent(new Event('imagesloaded'));
        }
    }

    getCurrentProgress()
    {
        return this.numberImagesLoaded / this.images.length;
    }

    addImage(image)
    {
        image.addEventListener(
            'load', () => {
                this.update();1
            }
        );

        this.images.push(image);
    }
}

function MainLoop(timestamp)
{
    if (lastRendered === undefined && lastTimestamp === undefined) {
        lastRendered = timestamp;
        lastTimestamp = timestamp;
    }

    let delta = (timestamp - lastTimestamp) / (10 / GAME_SPEED);

    if (KeyLeft.isPressed()) {
        mrCroc.moveLeft(timestamp, delta);
    } else if (KeyRight.isPressed()) {
        mrCroc.moveRight(timestamp, delta);
    }

    if (lastRendered >= FRAME_DURATION) {
        context.clearRect(0, 0, window.innerWidth, window.innerHeight);

        ground.draw(context);
        mrCroc.draw(context);
        lastRendered = timestamp;
    }

    lastTimestamp = timestamp;

    window.requestAnimationFrame(MainLoop);
}

const FPS = 60;
const FRAME_DURATION = 1000 / FPS;
const GAME_SPEED = 1;

let lastRendered = undefined;
let lastTimestamp = undefined;
let context;
let ground, mrCroc;

let KeyLeft = new Key('ArrowLeft');
let KeyRight = new Key('ArrowRight');

let loader = new ImageLoader();

let image = new Image();
image.src = 'graphics/mr-croc-stand.png';
loader.addImage(image);

let imgAnimation = new Image();
imgAnimation.src = 'graphics/mr-croc-walk-right.png';
loader.addImage(imgAnimation);

let imgAnimationB = new Image();
imgAnimationB.src = 'graphics/mr-croc-walk-left.png';
loader.addImage(imgAnimationB);

let imgBackground = new Image();
imgBackground.src = 'graphics/ground.jpg';
loader.addImage(imgBackground);

window.addEventListener(
    'imagesloaded',
    () => {
        console.log('Loaded');
        ground = new RetroSprite('graphics/ground.jpg', 4);
        ground.position.y = window.innerHeight - ground.getRect().height;

        let canvas = document.getElementById('canvas');
        canvas.width = window.innerWidth;
        canvas.height = window.innerHeight;

        context = canvas.getContext('2d');

        mrCroc = new MrCroc();
        mrCroc.position.x = 100;
        mrCroc.position.y = window.innerHeight - ground.getHeight();
        ground.draw(context);

        window.requestAnimationFrame(MainLoop);
    }
);