import { Request, TerrainData, Rectangle } from 'cesium'; import * as turf from '@turf/turf'; import { Feature, Polygon } from '@turf/turf'; const MAX_SHORT = 32767; interface ModelEdit { polygon: Feature < Polygon > ; polygonTriangles: Feature < Polygon > []; // TIN algorithm result on polygon } export class TerrainProviderEdit extends Cesium.CesiumTerrainProvider { private modelEdits: ModelEdit[] = []; constructor({ url, modelEdits }: { url: string;modelEdits: ModelEdit[] }) { super({ url }); this.modelEdits = modelEdits; } requestTileGeometry(x: number, y: number, level: number, request: Request): Promise < TerrainData > | undefined { const promise = super.requestTileGeometry(x, y, level, request); if (!promise || this.modelEdits.length === 0) { return promise; } const tileRectangle: Rectangle = this.tilingScheme.tileXYToRectangle(x, y, level); const tilePolygon = GeoUtils.rectangleToPolygon(tileRectangle); // Create turf polygon from tile rectangle const relevantEdits = this.modelEdits.filter(edit => turf.booleanOverlap(edit.polygon, tilePolygon) || turf.booleanContains(edit.polygon, tilePolygon)); if (relevantEdits.length === 0) { return promise; } return promise.then((data: TerrainData) => this.modifyTerrainTile(data, tileRectangle, relevantEdits)); } private modifyTerrainTile(terrainData: TerrainData, tileRectangle: Rectangle, modelEdits: ModelEdit[]) { const data = terrainData as any; const minimumHeight = data._minimumHeight; const maximumHeight = data._maximumHeight; const quantizedVertices: Uint16Array = data._quantizedVertices; const vertexCount = quantizedVertices.length / 3; const positions: number[][] = []; for (let i = 0; i < vertexCount; i++) { const rawU = quantizedVertices[i]; const rawV = quantizedVertices[i + vertexCount]; const rawH = quantizedVertices[i + vertexCount * 2]; const u = rawU / MAX_SHORT; const v = rawV / MAX_SHORT; const longitude = Cesium.Math.toDegrees(Cesium.Math.lerp(tileRectangle.west, tileRectangle.east, u)); const latitude = Cesium.Math.toDegrees(Cesium.Math.lerp(tileRectangle.south, tileRectangle.north, v)); let height = Cesium.Math.lerp(minimumHeight, maximumHeight, rawH / MAX_SHORT); const currentPoint = turf.point([longitude, latitude]); const relevantEdit = modelEdits.find(edit => turf.booleanPointInPolygon(currentPoint, edit.polygon)); if (relevantEdit) { const relevantTriangle = relevantEdit.polygonTriangles.find(triangle => turf.booleanPointInPolygon(currentPoint, triangle)); if (relevantTriangle) { height = turf.planepoint(currentPoint, relevantTriangle); } } positions.push([longitude, latitude, height]); } // TODO: split mesh triangles that are crossing the user polygon's perimiter and recreate mesh const heights = positions.map(p => p[2]); const newMinHeight = Math.min(...heights); const newMaxHeight = Math.max(...heights); const newQuantizedVertices = new Uint16Array(positions.length * 3); positions.forEach((p, i) => { const lonRad = Cesium.Math.toRadians(p[0]); newQuantizedVertices[i] = Math.round(Cesium.Math.lerp(MAX_SHORT, 0, (lonRad - tileRectangle.east) / (tileRectangle.west - tileRectangle.east))); const latRad = Cesium.Math.toRadians(p[1]); newQuantizedVertices[i + positions.length] = Math.round(Cesium.Math.lerp(MAX_SHORT, 0, (latRad - tileRectangle.north) / (tileRectangle.south - tileRectangle.north))); const relativeHeight = Math.round(Cesium.Math.lerp(0, MAX_SHORT, (p[2] - newMinHeight) / (newMaxHeight - newMinHeight))); newQuantizedVertices[i + positions.length * 2] = relativeHeight; }); data._minimumHeight = newMinHeight; data._maximumHeight = newMaxHeight; data._quantizedVertices = newQuantizedVertices; return data as TerrainData; } }
标签：const,TerrainProviderEdit,tileRectangle,Cesium,turf,data,Math From： https://www.cnblogs.com/zany-hui/p/17665228.html