Fence

Example

Example Source Code

import React, { useCallback, useEffect, useRef, useState } from 'react'
import ReactDOM from 'react-dom'
import * as THREE from 'three'
import { MbMap, MbTiandituLayer } from '@mapbox-react/core'

const App = () => {
  const [mapCenter] = useState([116.390714, 39.916535])
  const [zoom, setZoom] = useState(13)
  const [pitch, setPitch] = useState(45)
  const mapInst = useRef<any>()

  let map: any
  const altitude = 0

  const mapCreated = (mapbox: any) => {
    map = mapbox
  }
  const add3DLayer = () => {
    loaderModels()
  }
  const loaderModels = () => {
    const modelAsMercatorCoordinate =
      map.mapboxgl.MercatorCoordinate.fromLngLat(mapCenter, altitude)

    // transformation parameters to position, rotate and scale the 3D model onto the map
    const modelTransform = {
      translateX: modelAsMercatorCoordinate.x,
      translateY: modelAsMercatorCoordinate.y,
      translateZ: modelAsMercatorCoordinate.z,
      /* Since our 3D model is in real world meters, a scale transform needs to be
       * applied since the CustomLayerInterface expects units in MercatorCoordinates.
       */
      scale: modelAsMercatorCoordinate.meterInMercatorCoordinateUnits(),
    }
    addThreeLayer(modelTransform, modelAsMercatorCoordinate)
  }
  const addThreeLayer = (modelTransform, modelAsMercatorCoordinate) => {
    const threeLayer = {
      id: '3d-model',
      type: 'custom',
      renderingMode: '3d',
      camera: null as unknown as THREE.PerspectiveCamera,
      scene: null as unknown as THREE.Scene,
      renderer: null as unknown as THREE.WebGLRenderer,
      onAdd(map, gl) {
        this.camera = new THREE.PerspectiveCamera()
        this.scene = new THREE.Scene()

        // fence range
        const boundaryArr = [
          [116.385394, 39.92098],
          [116.38591, 39.911632],
          [116.389942, 39.911565],
          [116.390457, 39.908734],
          [116.392174, 39.908733],
          [116.39226, 39.911959],
          [116.396294, 39.911894],
          [116.395691, 39.921438],
          [116.385394, 39.92098],
        ]

        const outer = boundaryArr
          .map((b) => getThreePoint(modelAsMercatorCoordinate, b))
          .map((p) => [p[0], -p[1], 0])
        const polygonMesh = addFencing(outer)
        polygonMesh.translateY(-200)
        this.scene.add(polygonMesh)

        {
          const skyColor = 0xb1e1ff // light blue
          const groundColor = 0xb97a20 // brownish orange
          const intensity = 3
          const light = new THREE.HemisphereLight(
            skyColor,
            groundColor,
            intensity
          )
          this.scene.add(light)
        }

        // use the Mapbox GL JS map canvas for three.js
        this.renderer = new THREE.WebGLRenderer({
          canvas: map.getCanvas(),
          context: gl,
          antialias: true,
        })

        this.renderer.autoClear = false
      },
      render(gl, matrix) {
        const m = new THREE.Matrix4().fromArray(matrix)
        const l = new THREE.Matrix4()
          .makeTranslation(
            modelTransform.translateX,
            modelTransform.translateY,
            modelTransform.translateZ
          )
          .scale(
            new THREE.Vector3(
              modelTransform.scale,
              -modelTransform.scale,
              modelTransform.scale
            )
          )

        this.camera.projectionMatrix = m.clone().multiply(l)
        this.camera.matrixWorldInverse = new THREE.Matrix4()
        this.renderer.resetState()

        this.renderer.render(this.scene, this.camera)
      },
    }
    map.addLayer(threeLayer as CustomLayerInterface)
  }
  const getThreePoint = (modelAsMercatorCoordinate, anotherPoint) => {
    const anotherPointModel = map.mapboxgl.MercatorCoordinate.fromLngLat(
      anotherPoint,
      altitude
    )
    const x =
      (anotherPointModel.x - modelAsMercatorCoordinate.x) /
      modelAsMercatorCoordinate.meterInMercatorCoordinateUnits()
    const y =
      (anotherPointModel.y - modelAsMercatorCoordinate.y) /
      modelAsMercatorCoordinate.meterInMercatorCoordinateUnits()
    return [x, y]
  }
  const addFencing = (points: number[][]) => {
    const height = 500

    const pointDistance: number[] = []
    const distance = points.reduce((totalDistance, point, index) => {
      let segmentDistance = 0
      if (index > 0) {
        const lastPoint = new THREE.Vector3(...points[index - 1])
        const currPoint = new THREE.Vector3(...point)
        segmentDistance = lastPoint.distanceTo(currPoint)
      }
      totalDistance += segmentDistance
      pointDistance.push(totalDistance)
      return totalDistance
    }, 0)

    const geometry = new THREE.BufferGeometry()
    const posArr: number[] = []
    const uvArr: number[] = []

    points.forEach((point, index) => {
      if (index == 0) return
      const lastPoint = points[index - 1]

      // 三角面1 triangle1
      posArr.push(...lastPoint)
      uvArr.push(pointDistance[index - 1] / distance, 0)
      posArr.push(...point)
      uvArr.push(pointDistance[index] / distance, 0)
      posArr.push(lastPoint[0], lastPoint[1], lastPoint[2] + height)
      uvArr.push(pointDistance[index - 1] / distance, 1)

      // 三角面2 triangle2
      posArr.push(...point)
      uvArr.push(pointDistance[index] / distance, 0)
      posArr.push(point[0], point[1], point[2] + height)
      uvArr.push(pointDistance[index] / distance, 1)
      posArr.push(lastPoint[0], lastPoint[1], lastPoint[2] + height)
      uvArr.push(pointDistance[index - 1] / distance, 1)
    })

    geometry.setAttribute(
      'position',
      new THREE.BufferAttribute(new Float32Array(posArr), 3)
    )
    geometry.setAttribute(
      'uv',
      new THREE.BufferAttribute(new Float32Array(uvArr), 2)
    )
    geometry.computeVertexNormals()

    const texture = new THREE.TextureLoader().load(
      `https://mapbox-web.github.io/mapbox-react/images/wall.png`
    )
    texture.wrapS = THREE.RepeatWrapping
    texture.wrapT = THREE.RepeatWrapping

    // 材质
    const material = new THREE.MeshBasicMaterial({
      color: 0x00ff00,
      map: texture,
      transparent: true,
      opacity: 0.9,
      depthWrite: false,
      side: THREE.DoubleSide,
    })

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

  return (
    <div className="map-wrapper">
      <MbMap
        ref={mapInst}
        center={mapCenter}
        zoom={zoom}
        pitch={pitch}
        onCreated={mapCreated}
      >
        <MbTiandituLayer types={['vec', 'cva']} onCreated={add3DLayer} />
      </MbMap>
    </div>
  )
}

ReactDOM.render(<App />, document.querySelector('#root'))