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Three.js 三维转屏幕坐标教程

news 2026/6/30 16:54:18

三维转屏幕坐标 ·World to Screen· ▶ 在线运行案例

案例合集：三维可视化功能案例（threehub.cn）
开源仓库github地址：https://github.com/z2586300277/three-cesium-examples
400个案例代码:网盘链接

你将学到什么

vector.project(camera)世界坐标 → NDC → 屏幕像素
不用 CSS2DRenderer 的手动 DOM 跟随写法
每帧在 rAF 里更新标签位置

效果说明

30 个小立方体，每个上方有一个绝对定位的 DOM（图片 + 文字 D0~D29），随立方体在屏幕上移动而移动，像简易版 3D 标牌。

核心概念

project 管线

世界坐标 (World)↓ matrixWorld × projectionMatrix NDC 归一化设备坐标 (-1 ~ 1) ↓ 视口变换 屏幕像素 (px)

const worldPosition = mesh.getWorldPosition(new THREE.Vector3());worldPosition.project(camera);
const screenX = (worldPosition.x + 1) / 2 * width; const screenY = (-worldPosition.y + 1) / 2 * height;div.style.left = screenX + 'px'; div.style.top = screenY + 'px';

注意Y 轴翻转：NDC 的 y 向上，屏幕 CSS 的 y 向下，故screenY取负。

与 CSS2DRenderer 对比

| 方式 | 本案例 | cssElement | |------|--------|-----------------------------------------------| | 实现 | 手算 project + DOM | CSS2DRenderer 自动投影 | | 深度遮挡 | 无，DOM 总在最上层 | 可选 | | 适用 | 理解原理、轻量标签 | 生产推荐 |

代码要点

import * as THREE from 'three'import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js'
const DOM = document.getElementById('box')
const scene = new THREE.Scene()
const camera = new THREE.PerspectiveCamera(75, DOM.clientWidth / DOM.clientHeight, 0.1, 1000)
camera.position.set(10, 10, 10)
const renderer = new THREE.WebGLRenderer()
renderer.setSize(DOM.clientWidth, DOM.clientHeight)
DOM.appendChild(renderer.domElement)
const controls = new OrbitControls(camera, renderer.domElement)
controls.enableDamping = true
scene.add(new THREE.AxesHelper(50))
const R = () => Math.random() * 10 - 5
const list = []
for (let i = 0; i < 30; i++) {
const div = createDom('D' + i)
const mesh = new THREE.Mesh(new THREE.BoxGeometry(0.3, 0.3, 0.3), new THREE.MeshBasicMaterial({ color: Math.random() * 0xffffff }))
mesh.position.set(R(), R(), R())
scene.add(mesh)
mesh.div = div
list.push(mesh)
}
function updateCSS2DVisibility() {
list.forEach(mesh => {
const worldPosition = mesh.getWorldPosition(new THREE.Vector3())
worldPosition.project(camera);
const width = renderer.domElement.clientWidth
const height = renderer.domElement.clientHeight
const screenX = (worldPosition.x + 1) / 2 * width
const screenY = (-worldPosition.y + 1) / 2 * height
mesh.div.style.left = screenX + 'px'
mesh.div.style.top = screenY + 'px' })
}
animate()
function animate() {
requestAnimationFrame(animate)
updateCSS2DVisibility()
controls.update()
renderer.render(scene, camera)
}
window.onresize = () => {
renderer.setSize(box.clientWidth, box.clientHeight)
camera.aspect = box.clientWidth / box.clientHeight
camera.updateProjectionMatrix()
}
// 创建dom function createDom(text) {
const div = document.createElement('div')
div.style.position = 'absolute'
const img = document.createElement('img')
img.src = HOST + '/files/author/KallkaGo.jpg'
img.style.width = '50px'
img.style.height = '50px'
div.appendChild(img)
div.innerHTML += text
div.style.color = 'white'
document.body.appendChild(div)
return div}