app.js

// Get the canvas element
const canvas = document.getElementById("renderCanvas");

// Create the Babylon.js engine
const engine = new BABYLON.Engine(canvas, true);

// Create the scene
const createScene = function() {
    // Create a basic scene
    const scene = new BABYLON.Scene(engine);

    // Create a camera
    const camera = new BABYLON.ArcRotateCamera("camera", 
        -Math.PI / 2, 
        Math.PI / 2.5, 
        10, 
        BABYLON.Vector3.Zero(), 
        scene
    );
    camera.attachControl(canvas, true);

    // Create a light
    const light = new BABYLON.HemisphericLight("light", 
        new BABYLON.Vector3(0, 1, 0), 
        scene
    );

    // Create a box
    const box = BABYLON.MeshBuilder.CreateBox("box", {}, scene);

    // Add some animation
    scene.registerBeforeRender(function() {
        box.rotation.y += 0.01;
    });

    return scene;
};

// Create the scene
const scene = createScene();

// Run the render loop
engine.runRenderLoop(function() {
    scene.render();
});

// Handle browser/canvas resize events
window.addEventListener("resize", function() {
    engine.resize();
});