three.js实现水面倒影效果

要实现水面倒影效果，可以使用three.js的水面倒影插件`three.js-water`。这个插件可以创建一个水面对象，并且将其反射到场景中，从而实现水面倒影效果。

以下是实现水面倒影效果的基本步骤：

1. 导入`three.js`和`three.js-water`插件。

import * as THREE from 'three';
import Water from 'three-water';

2. 创建场景、渲染器和相机。

const scene = new THREE.Scene();
const renderer = new THREE.WebGLRenderer();
const camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 1, 1000);
camera.position.set(0, 100, 200);
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);

3. 创建水面对象。

const waterGeometry = new THREE.PlaneBufferGeometry(10000, 10000);
const water = new Water(waterGeometry, {
    color: 'blue',
    scale: 5,
    flowDirection: new THREE.Vector2(1, 1),
    textureWidth: 512,
    textureHeight: 512,
    reflectivity: 0.3
});
water.rotation.x = -Math.PI / 2;
scene.add(water);

4. 创建地面对象，并将其添加到场景中。

const groundGeometry = new THREE.PlaneBufferGeometry(10000, 10000);
const groundMaterial = new THREE.MeshPhongMaterial({
    color: 0x999999,
    depthWrite: false
});
const ground = new THREE.Mesh(groundGeometry, groundMaterial);
ground.rotation.x = -Math.PI / 2;
scene.add(ground);

5. 创建一个立方体，并将其添加到场景中。

const cubeGeometry = new THREE.BoxBufferGeometry(50, 50, 50);
const cubeMaterial = new THREE.MeshPhongMaterial({
    color: 'red'
});
const cube = new THREE.Mesh(cubeGeometry, cubeMaterial);
cube.position.set(0, 25, 0);
scene.add(cube);

6. 创建一个点光源，并将其添加到场景中。

const light = new THREE.PointLight('white', 1, 1000);
light.position.set(0, 200, 0);
scene.add(light);

7. 使用`three.js-water`插件提供的`update`方法更新水面对象。

function animate() {
    requestAnimationFrame(animate);
    water.material.uniforms.time.value += 1.0 / 60.0;
    water.render();
    renderer.render(scene, camera);
}
animate();

通过以上步骤，就可以在three.js中实现水面倒影效果了。完整的代码示例可以参考`three.js-water`插件的官方文档。