three.js 使用geojson ，实现中国地图区域，边缘流动效果

three.js 使用geojson ，实现中国地图区域，边缘流动效果

在线链接：https://threehub.cn/#/codeMirror?navigation=ThreeJS&classify=expand&id=geoBorder

国内站点预览：http://threehub.cn

github地址: https://github.com/z2586300277/three-cesium-examples

import * as THREE from 'three'
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js'

const box = document.getElementById('box')

const scene = new THREE.Scene()

const camera = new THREE.PerspectiveCamera(75, box.clientWidth / box.clientHeight, 0.1, 1000)

camera.position.set(0, 0, 500)

const renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true, logarithmicDepthBuffer: true })

renderer.setSize(box.clientWidth, box.clientHeight)

box.appendChild(renderer.domElement)

const controls = new OrbitControls(camera, renderer.domElement)

controls.enableDamping = true

scene.add(new THREE.AmbientLight(0xffffff, 1))

const directionalLight = new THREE.DirectionalLight(0xffffff, 2)

directionalLight.position.set(300, 300, 300)

scene.add(directionalLight)

const map = new THREE.TextureLoader().load(`https://file.threehub.cn/` + 'images/channels/lmap.png')

map.wrapS = THREE.RepeatWrapping

map.wrapT = THREE.RepeatWrapping

map.needsUpdate = true

animate()

function animate() {

  requestAnimationFrame(animate)

  map.offset.x += 0.001

  controls.update()

  renderer.render(scene, camera)

}

window.onresize = () => {

  renderer.setSize(box.clientWidth, box.clientHeight)

  camera.aspect = box.clientWidth / box.clientHeight

  camera.updateProjectionMatrix()

}

/* 边界 */
const group = new THREE.Group()

fetch(`https://file.threehub.cn/` + 'files/json/chinaBound.json').then(r => r.json()).then(res => {

  const { features } = res

  features.forEach((i) => {

    if (i.geometry.type === 'MultiPolygon') i.geometry.coordinates.forEach((j) => j.forEach((z) => createShapeWithCoord(group, z)))

    else if (i.geometry.type === 'Polygon') i.geometry.coordinates.forEach((j) => createShapeWithCoord(group, j))

    else if (i.geometry.type === 'LineString') i.geometry.coordinates.length > 1 && createShapeWithCoord(group, i.geometry.coordinates)

  })

  translationOriginForGroup(group)

  scene.add(group)

})

function createShapeWithCoord(group, coordinates) {
  
  if (coordinates.length < 1000) return // 设置点数限制 如果点太少则不绘制

  const curvePoints = coordinates.map((k) => coordToVector3(k))

  const curve = new THREE.CatmullRomCurve3(curvePoints)

  const geometry = new THREE.TubeGeometry(curve, curvePoints.length - 1, 1, 40, false)

  const material = new THREE.MeshPhongMaterial({ color: 0xffffff , map , transparent: true })

  const mesh = new THREE.Mesh(geometry, material)

  translationOriginForMesh(mesh)

  group.attach(mesh)

}

function coordToVector3(coord, slace = 10000) {

  const [lng, lat] = coord

  const x = lng * 20037508.34 / 180

  const y = Math.log(Math.tan((90 + lat) * Math.PI / 360)) / (Math.PI / 180) * 20037508.34 / 180

  return new THREE.Vector3(x / slace, y / slace, 0)

}

function translationOriginForMesh(mesh) {
    
  const boundingBox = new THREE.Box3().setFromObject(mesh)

  boundingBox.getCenter(mesh.position)

  mesh.geometry.center()

}

// 设置组中心点
function translationOriginForGroup(group) {

  const boundingBox = new THREE.Box3().setFromObject(group)

  boundingBox.getCenter(group.position)

  group.traverse((c) => {

      c.isMesh && c.position.sub(group.position)

  })

  group.position.set(0, 0, 0)

}

/**
 * 名称: 地理边界
 * 作者: 优雅永不过时 https://github.com/z2586300277
*/