createShelfDoors(scene, bookcase) gives a bookcase two glass doors, each the child of a hinge TransformNode at the outer edge, and returns a group with one eased animation per hinge (side -1 or 1):
const swing = new BABYLON.Animation(`swing${side}`, 'rotation.y', 60,
BABYLON.Animation.ANIMATIONTYPE_FLOAT);
swing.setKeys([{ frame: 0, value: 0 }, { frame: 45, value: -side * 1.9 }]); // outward
swing.setEasingFunction(ease);
group.addTargetedAnimation(swing, hinge);A second helper, presentBook(scene, book), returns a group that slides a book 0.3 m out over 20 frames, then lifts it and turns its front cover (the +x face) to the aisle; start(false, 1, 40, 0) plays it backward to shelve the book. Actions and Picking runs it when a visitor clicks a spine:
<canvas id="view" style="width: 620px; height: 190px"></canvas>
<script src="https://cdn.jsdelivr.net/npm/babylonjs@9.28.0/babylon.js"></script>
<script src="bookstore.js"></script>
<script>
(async () => {
const engine = new BABYLON.Engine(view, true, {}, true);
const scene = BookNestStore.createScene(engine);
BookNestStore.createRoom(scene);
const left = BookNestStore.createBookcase(scene, 'bookcaseLeft', -1.8);
const right = BookNestStore.createBookcase(scene, 'bookcaseRight', 1.8);
const books = BookNestStore.placeBooks(scene, left);
BookNestStore.coverBooks(scene, books);
BookNestStore.lightRoom(scene);
const doors = BookNestStore.createShelfDoors(scene, right); // after lightRoom: no shadow
const present = BookNestStore.presentBook(scene, books[2]);
new BABYLON.ArcRotateCamera('aisle', -1.9, 1.4, 3.1, new BABYLON.Vector3(-0.2, 1.3, 2.3));
await scene.whenReadyAsync(); // covers loaded, shaders compiled
engine.runRenderLoop(() => scene.render());
present.start(false, 1, 0, 40); // all the way out
doors.start(false, 1, 0, 30).onAnimationGroupEndObservable.addOnce(() => {
window.__done = true; // two thirds open: capture
});
})();
</script>
The doors stop at frame 30 of 45, two thirds open.
<!doctype html>
<style>
body { margin: 0; background: #f7f3ec; font: 13px system-ui, sans-serif; color: #333; }
canvas { width: 100%; max-width: 600px; height: 320px; display: block; touch-action: none; outline: none; }
</style>
<canvas id="view"></canvas>
<script src="https://cdn.jsdelivr.net/npm/babylonjs@9.28.0/babylon.js"></script>
<script>
// ---- BookNest's bookstore: the helpers the book keeps in bookstore.js ----
const ROOM = { width: 8, depth: 6, height: 3, wall: 0.15 };
const BOOKS = [
{ id: 1, title: 'The Quiet Harbor', author: 'Mara Ellison', color: '#1f5f8b', pages: 312, price: 14.99, rating: 4.6, inStock: true },
{ id: 2, title: 'Patterns of the Deep Web', author: 'Tomas Reyes', color: '#5b3f99', pages: 428, price: 32.5, rating: 4.4, inStock: true },
{ id: 3, title: 'Salt and Saffron', author: 'Priya Nair', color: '#e09a10', pages: 256, price: 24, rating: 4.8, inStock: false },
{ id: 4, title: 'Small Steps to Big Summits', author: 'Dana Whitfield', color: '#3f7d3a', pages: 198, price: 18.5, rating: 4.3, inStock: true },
{ id: 5, title: "The Clockmaker's Paradox", author: 'Julian Voss', color: '#b5452f', pages: 344, price: 16.75, rating: 4.7, inStock: true },
{ id: 6, title: 'Gardens in Glass', author: 'Lena Hart', color: '#2a9d8f', pages: 176, price: 21.3, rating: 4.5, inStock: true },
];
function createScene(engine) {
const scene = new BABYLON.Scene(engine);
scene.clearColor = BABYLON.Color4.FromHexString('#cfd8dcff');
const sky = new BABYLON.HemisphericLight('sky', new BABYLON.Vector3(0.3, 1, -0.4), scene);
sky.groundColor = new BABYLON.Color3(0.35, 0.32, 0.3);
return scene;
}
function paint(scene, name, hex) { // a matte color
const material = new BABYLON.StandardMaterial(name, scene);
material.diffuseColor = BABYLON.Color3.FromHexString(hex);
material.specularColor = BABYLON.Color3.Black();
return material;
}
function createRoom(scene) { // floor and three walls, front open
const room = new BABYLON.TransformNode('room', scene);
const floor = BABYLON.MeshBuilder.CreateGround('floor', { width: ROOM.width, height: ROOM.depth }, scene);
floor.material = paint(scene, 'oak', '#b08d6a');
floor.parent = room;
const plaster = paint(scene, 'plaster', '#fff3e0');
for (const [name, width, x, z] of [['backWall', 8, 0, 3], ['leftWall', 6, -4, 0], ['rightWall', 6, 4, 0]]) {
const wall = BABYLON.MeshBuilder.CreateBox(name, { width, height: ROOM.height, depth: ROOM.wall }, scene);
wall.position.set(x, ROOM.height / 2, z);
wall.rotation.y = x ? Math.PI / 2 : 0;
wall.material = plaster;
wall.parent = room;
}
return room;
}
function createBookcase(scene, name, x) { // 8 boxes merged into 1 mesh
const [w, h, d, t] = [3, 2.2, 0.35, 0.04];
const parts = [[t, h, d, -w / 2, h / 2, 0], [t, h, d, w / 2, h / 2, 0], [w, h, t, 0, h / 2, d / 2 - t / 2]];
for (let i = 0; i < 5; i++) parts.push([w, t, d, 0, 0.1 + i * 0.5, 0]);
const bookcase = BABYLON.Mesh.MergeMeshes(parts.map(([width, height, depth, px, py, pz]) => {
const part = BABYLON.MeshBuilder.CreateBox('part', { width, height, depth }, scene);
part.position.set(px, py, pz);
return part;
}), true);
bookcase.name = name;
bookcase.material = paint(scene, 'walnut', '#6d4c33');
bookcase.position.set(x, 0, ROOM.depth / 2 - ROOM.wall / 2 - d / 2); // against the back wall
return bookcase;
}
function drawCover(scene, book) { // cover art painted on a canvas
const tex = new BABYLON.DynamicTexture('cover' + book.id, { width: 256, height: 384 }, scene);
const c = tex.getContext();
c.fillStyle = book.color; c.fillRect(0, 0, 256, 384);
c.fillStyle = 'rgba(0,0,0,0.4)'; c.fillRect(0, 0, 18, 384); // the dark left edge
c.strokeStyle = '#fff8e1'; c.lineWidth = 3; c.strokeRect(34, 24, 202, 336);
c.fillStyle = '#fff8e1'; c.textAlign = 'center'; c.font = 'bold 30px Georgia';
const lines = [''];
for (const word of book.title.split(' ')) {
const test = (lines[lines.length - 1] + ' ' + word).trim();
if (c.measureText(test).width > 180) lines.push(word); else lines[lines.length - 1] = test;
}
lines.forEach((line, i) => c.fillText(line, 135, 110 + i * 38));
c.font = '20px Georgia'; c.fillText(book.author, 135, 330);
tex.update();
return tex;
}
function placeBooks(scene, bookcase, shelf = 2) { // six books, spines out, covers on +x
const strip = new BABYLON.Vector4(0, 0, 0.07, 1);
const faceUV = [strip, strip, new BABYLON.Vector4(0, 0, 1, 1), strip, strip, strip];
let x = -0.35; // left end of the row, local to the bookcase
return BOOKS.map((record) => {
const width = record.pages / 4000 + 0.02; // spine thickness from page count
const book = BABYLON.MeshBuilder.CreateBox(`book${record.id}`, { width, height: 0.3, depth: 0.22, faceUV, wrap: true }, scene);
book.parent = bookcase;
book.position.set(x + width / 2, 0.12 + shelf * 0.5 + 0.15, -0.02);
x += width + 0.012;
book.material = new BABYLON.StandardMaterial(record.title, scene);
book.material.diffuseTexture = drawCover(scene, record);
book.material.specularColor = new BABYLON.Color3(0.15, 0.15, 0.15);
book.metadata = record; // the record, for picking
return book;
});
}
// The book cuts the storefront with CSG2 (Manifold WebAssembly); this sandbox cannot download
// the .wasm, so the older pure-JavaScript BABYLON.CSG makes the same cuts here.
function createFrontWall(scene) {
const box = (width, height, depth, x, y) => {
const mesh = BABYLON.MeshBuilder.CreateBox('cut', { width, height, depth }, scene);
mesh.position.set(x, y, -ROOM.depth / 2);
return mesh;
};
const solid = box(ROOM.width, ROOM.height, ROOM.wall, 0, ROOM.height / 2);
const windowHole = box(3.2, 1.6, 1, -1.4, 1.6), doorHole = box(1.1, 2.2, 1, 2.3, 1.1);
const wall = BABYLON.CSG.FromMesh(solid).subtract(BABYLON.CSG.FromMesh(windowHole))
.subtract(BABYLON.CSG.FromMesh(doorHole)).toMesh('frontWall', scene.getMaterialByName('plaster'), scene);
[solid, windowHole, doorHole].forEach((mesh) => mesh.dispose());
return wall;
}
// ---- end of the bookstore helpers ----
function lightRoom(scene) { // call after the meshes exist
scene.getLightByName('sky').intensity = 0.5; // the sky light becomes fill light
const sun = new BABYLON.DirectionalLight('sun', new BABYLON.Vector3(0.2, -0.33, 1), scene);
sun.intensity = 0.8;
sun.diffuse = BABYLON.Color3.FromHexString('#fff1d6'); // warm afternoon sun
const ceiling = BABYLON.MeshBuilder.CreateBox('ceiling', { width: ROOM.width, height: ROOM.wall, depth: ROOM.depth }, scene);
ceiling.position.y = ROOM.height + ROOM.wall / 2;
ceiling.layerMask = 0x10000000; // no camera draws it; it still casts
const shadows = new BABYLON.CascadedShadowGenerator(2048, sun);
Object.assign(shadows, { numCascades: 3, shadowMaxZ: 20, lambda: 1,
autoCalcDepthBounds: true, bias: 0.002, normalBias: 0.01 });
for (const mesh of scene.meshes) {
if (mesh.name !== 'floor') shadows.addShadowCaster(mesh);
mesh.receiveShadows = true;
}
const lamp = new BABYLON.PointLight('lamp', new BABYLON.Vector3(-1.2, 2.3, 1.4), scene);
lamp.diffuse = BABYLON.Color3.FromHexString('#ffd9a0');
Object.assign(lamp, { intensity: 0.7, range: 5 }); // a warm reading lamp
return { sun, lamp, shadows };
}
function presentBook(scene, book) { // slide out, lift, turn the cover to the aisle
const group = new BABYLON.AnimationGroup('present' + book.name, scene);
const track = (property, type, keys) => {
const animation = new BABYLON.Animation(property, property, 60, type);
animation.setKeys(keys.map(([frame, value]) => ({ frame, value })));
const ease = new BABYLON.CubicEase();
ease.setEasingMode(BABYLON.EasingFunction.EASINGMODE_EASEINOUT);
animation.setEasingFunction(ease);
group.addTargetedAnimation(animation, book);
};
const { z, y } = book.position;
const FLOAT = BABYLON.Animation.ANIMATIONTYPE_FLOAT;
track('position.z', FLOAT, [[0, z], [20, z - 0.3], [40, z - 0.3]]); // 0.3 m out in 20 frames
track('position.y', FLOAT, [[0, y], [20, y], [40, y + 0.12]]); // then lift it
track('rotation.y', FLOAT, [[0, 0], [20, 0], [40, Math.PI / 2]]); // and face the +x cover out
return group;
}
function createShelfDoors(scene, bookcase) { // two glass doors on hinge nodes
const glass = new BABYLON.StandardMaterial('doorGlass', scene);
glass.diffuseColor = BABYLON.Color3.FromHexString('#cfe8f0');
glass.alpha = 0.35;
const group = new BABYLON.AnimationGroup('doors', scene);
const ease = new BABYLON.CubicEase();
ease.setEasingMode(BABYLON.EasingFunction.EASINGMODE_EASEINOUT);
for (const side of [-1, 1]) {
const hinge = new BABYLON.TransformNode(`hinge${side}`, scene);
hinge.parent = bookcase;
hinge.position.set(side * 1.5, 1.1, -0.19); // the outer front edge
const door = BABYLON.MeshBuilder.CreateBox(`door${side}`, { width: 1.5, height: 2.2, depth: 0.02 }, scene);
door.parent = hinge;
door.position.x = -side * 0.75; // the door hangs inward from its hinge
door.material = glass;
const swing = new BABYLON.Animation(`swing${side}`, 'rotation.y', 60, BABYLON.Animation.ANIMATIONTYPE_FLOAT);
swing.setKeys([{ frame: 0, value: 0 }, { frame: 45, value: -side * 1.9 }]); // outward
swing.setEasingFunction(ease);
group.addTargetedAnimation(swing, hinge);
}
return group;
}
const canvas = document.getElementById('view');
const engine = new BABYLON.Engine(canvas, true, {}, true);
const scene = createScene(engine);
createRoom(scene);
const left = createBookcase(scene, 'bookcaseLeft', -1.8);
const right = createBookcase(scene, 'bookcaseRight', 1.8);
const books = placeBooks(scene, left);
lightRoom(scene);
const doors = createShelfDoors(scene, right); // after lightRoom: glass casts no shadow
const present = presentBook(scene, books[2]);
const camera = new BABYLON.ArcRotateCamera('aisle', -1.9, 1.4, 3.6, new BABYLON.Vector3(-0.2, 1.3, 2.3), scene);
camera.minZ = 0.05;
camera.attachControl(canvas, true);
engine.runRenderLoop(() => scene.render());
// Open and present, pause, then play both groups backward: start(loop, speed, from, to)
const ended = (group) => new Promise((resolve) => group.onAnimationGroupEndObservable.addOnce(resolve));
const wait = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
async function cycle() {
present.start(false, 1, 0, 40); // all the way out
doors.start(false, 1, 0, 45);
await ended(doors);
await wait(1500);
present.start(false, 1, 40, 0); // backward: shelve the book again
doors.start(false, 1, 45, 0);
await ended(doors);
await wait(1000);
cycle();
}
cycle();
addEventListener('resize', () => engine.resize());
</script>