Cosmic 3D — 三维宇宙可视化

// ── Scene ──
const scene = new THREE.Scene();
scene.background = new THREE.Color(0x070714);

// ── Camera ──
const camera = new THREE.PerspectiveCamera(70, innerWidth / innerHeight, 0.1, 3000);
camera.position.set(0, 0, 400);

// ── Renderer ──
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(innerWidth, innerHeight);
renderer.setPixelRatio(Math.min(devicePixelRatio, 2));

// ── Controls ──
const controls = new OrbitControls(camera, renderer.domElement);
controls.enableDamping = true;
controls.autoRotate = true;
controls.autoRotateSpeed = 0.3;

// ── Main stars (sphere distribution) ──
const starGeo = new THREE.BufferGeometry();
const positions = new Float32Array(4000 * 3);
const colors = new Float32Array(4000 * 3);
const sizes = new Float32Array(4000);

for (let i = 0; i < 4000; i++) {
  const theta = Math.random() * Math.PI * 2;
  const phi = Math.acos(2 * Math.random() - 1);
  const r = 100 + Math.random() * 500;
  positions[i*3] = r * Math.sin(phi) * Math.cos(theta);
  positions[i*3+1] = r * Math.cos(phi);
  positions[i*3+2] = r * Math.sin(phi) * Math.sin(theta);
  const c = new THREE.Color().setHSL(0.58 + Math.random() * 0.15, 0.6, 0.5 + Math.random() * 0.4);
  colors[i*3] = c.r; colors[i*3+1] = c.g; colors[i*3+2] = c.b;
  sizes[i] = 0.5 + Math.random() * 2;
}

starGeo.setAttribute('position', new THREE.BufferAttribute(positions, 3));
starGeo.setAttribute('color', new THREE.BufferAttribute(colors, 3));
starGeo.setAttribute('size', new THREE.BufferAttribute(sizes, 1));

const starMat = new THREE.PointsMaterial({
  size: 1.2, vertexColors: true, transparent: true,
  opacity: 0.9, blending: THREE.AdditiveBlending, depthWrite: false,
});
const stars = new THREE.Points(starGeo, starMat);
scene.add(stars);

// ── 星云生成 ──
function createNebula(pos, size, color, count) {
  const geo = new THREE.BufferGeometry();
  const p = new Float32Array(count * 3);
  const c = new Float32Array(count * 3);
  const base = new THREE.Color(color);
  for (let i = 0; i < count; i++) {
    const r = Math.random() * size;
    const theta = Math.random() * Math.PI * 2;
    const phi = Math.acos(2 * Math.random() - 1);
    p[i*3] = pos[0] + r * Math.sin(phi) * Math.cos(theta);
    p[i*3+1] = pos[1] + r * Math.cos(phi) * 0.3;
    p[i*3+2] = pos[2] + r * Math.sin(phi) * Math.sin(theta);
    const col = base.clone().lerp(new THREE.Color(0x000000), Math.random() * 0.7);
    c[i*3] = col.r; c[i*3+1] = col.g; c[i*3+2] = col.b;
  }
  geo.setAttribute('position', new THREE.BufferAttribute(p, 3));
  geo.setAttribute('color', new THREE.BufferAttribute(c, 3));
  return new THREE.Points(geo, new THREE.PointsMaterial({
    size: 3, vertexColors: true, transparent: true,
    opacity: 0.3, blending: THREE.AdditiveBlending, depthWrite: false,
  }));
}

// ── 光环生成 ──
function createRing(radius, colorY, tiltX, speed) {
  const count = 2000;
  const geo = new THREE.BufferGeometry();
  const p = new Float32Array(count * 3);
  for (let i = 0; i < count; i++) {
    const angle = Math.random() * Math.PI * 2;
    const r = radius + (Math.random() - 0.5) * 30;
    p[i*3] = r * Math.cos(angle);
    p[i*3+1] = (Math.random() - 0.5) * 4;
    p[i*3+2] = r * Math.sin(angle);
  }
  geo.setAttribute('position', new THREE.BufferAttribute(p, 3));
  return { mesh: new THREE.Points(geo, new THREE.PointsMaterial({
    color: new THREE.Color().setHSL(colorY, 0.8, 0.5), size: 1.2,
    transparent: true, opacity: 0.4, blending: THREE.AdditiveBlending,
  })), speed, tiltX };
}

// 添加光环
const rings = [createRing(250, 0.5, 0.3, 0.0008),
               createRing(400, 0.7, -0.5, -0.0005),
               createRing(180, 0.3, 0.8, 0.0012)];
rings.forEach(r => { r.mesh.rotation.x = r.tiltX; scene.add(r.mesh); });