Zellige → pixel → volume

// Transition 2D -> 3D : chaque tesselle du zellige
// est convertie en geometrie extrudee
function extrudeTile(shape2D, depth) {
  const extrudeSettings = {
    depth: depth,
    bevelEnabled: true,
    bevelThickness: depth * 0.1,
    bevelSize: depth * 0.05,
    bevelSegments: 2
  };
  return new THREE.ExtrudeGeometry(shape2D, extrudeSettings);
}

// Pattern zellige : etoile a 8 branches + croix
function createZelligeStar(cx, cy, r) {
  const shape = new THREE.Shape();
  const pts = 16;
  for (let i = 0; i < pts; i++) {
    const angle = (i / pts) * Math.PI * 2;
    const radius = i % 2 === 0 ? r : r * 0.55;
    const x = cx + Math.cos(angle) * radius;
    const y = cy + Math.sin(angle) * radius;
    i === 0 ? shape.moveTo(x, y) : shape.lineTo(x, y);
  }
  shape.closePath();
  return shape;
}