lg_frontend/static/libs/mars3d/thirdParty/pbf-mapbox/PbfLayer.js

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// import * as mars3d from "mars3d"
// const Cesium = mars3d.Cesium
// 按mars3d规范封装的pbf图层
;(function (window) {
const BasicRenderer = window.mapboxRenderer.BasicRenderer
// 创建一个全局变量作为pbfBasicRenderer渲染模板避免出现16个canvas上下文的浏览器限制以便Cesium ImageLayer.destory()正常工作。
// https://github.com/mapbox/mapbox-gl-js/issues/7332
const OFFSCREEN_CANV_SIZE = 1024
const baseCanv = document.createElement("canvas")
baseCanv.style.imageRendering = "pixelated"
baseCanv.addEventListener("webglcontextlost", () => console.log("webglcontextlost"), false)
baseCanv.width = OFFSCREEN_CANV_SIZE
baseCanv.height = OFFSCREEN_CANV_SIZE
class MVTImageryProvider {
/**
*
* @param {Object} options
* @param {Object} options.style - mapbox style object
* @param {Function} [options.sourceFilter] - sourceFilter is used to filter which source participate in pickFeature process.
* @param {Number} [options.maximumLevel] - if cesium zoom level exceeds maximumLevel, layer will be invisible.
* @param {Number} [options.minimumLevel] - if cesium zoom level belows minimumLevel, layer will be invisible.
* @param {Number} [options.tileSize=512] - can be 256 or 512.
* @param {Boolean} [options.hasAlphaChannel] -
* @param {String} [options.credit] -
*
*/
constructor(options) {
this.options = options
let pbfStyle = options.style
this.mapboxRenderer = new BasicRenderer({
style: pbfStyle
})
this.mapboxRenderer._transformRequest = (url, resourceType) => {
return this.transformRequest(url, resourceType)
}
this.mapboxRenderer._canvas = baseCanv
this.mapboxRenderer._canvas.addEventListener("webglcontextrestored", () => this.mapboxRenderer._createGlContext(), false)
this.mapboxRenderer._createGlContext()
if (options.showCanvas) {
this.mapboxRenderer.showCanvasForDebug()
}
this.ready = false
this.readyPromise = this.mapboxRenderer._style.loadedPromise.then(() => {
this.ready = true
})
this.tilingScheme = options.tilingScheme ?? new Cesium.WebMercatorTilingScheme()
this.rectangle = this.tilingScheme.rectangle
this.tileSize = this.tileWidth = this.tileHeight = options.tileSize || 512
this.maximumLevel = options.maximumLevel || Number.MAX_SAFE_INTEGER
this.minimumLevel = options.minimumLevel || 0
this.tileDiscardPolicy = undefined
this.errorEvent = new Cesium.Event()
this.credit = new Cesium.Credit(options.credit || "", false)
this.proxy = new Cesium.DefaultProxy("")
this.hasAlphaChannel = options.hasAlphaChannel ?? true
this.sourceFilter = options.sourceFilter
}
transformRequest = (url) => {
if (this.options.transformUrl) {
url = this.options.transformUrl(url)
}
return { url: url, headers: this.options.headers || {}, credentials: "" }
}
getTileCredits(x, y, level) {
return []
}
createTile() {
const canv = document.createElement("canvas")
canv.width = this.tileSize
canv.height = this.tileSize
canv.style.imageRendering = "pixelated"
const ctx = canv.getContext("2d")
if (ctx) {
ctx.globalCompositeOperation = "copy"
}
return canv
}
_getTilesSpec(coord, source) {
const { x, y, zoom } = coord
const TILE_SIZE = this.tileSize
// 3x3 grid of source tiles, where the region of interest is that corresponding to the central source tile
const ret = []
const maxTile = (1 << zoom) - 1
for (let xx = -1; xx <= 1; xx++) {
let newx = x + xx
if (newx < 0) {
newx = maxTile
}
if (newx > maxTile) {
newx = 0
}
for (let yy = -1; yy <= 1; yy++) {
const newy = y + yy
if (newy < 0) {
continue
}
if (newy > maxTile) {
continue
}
ret.push({
source: source,
z: zoom,
x: newx,
y: newy,
left: 0 + xx * TILE_SIZE,
top: 0 + yy * TILE_SIZE,
size: TILE_SIZE
})
}
}
return ret
}
requestImage(x, y, zoom, releaseTile = true) {
if (zoom > this.maximumLevel || zoom < this.minimumLevel) {
return Promise.reject(undefined)
}
this.mapboxRenderer.filterForZoom(zoom)
const tilesSpec = this.mapboxRenderer.getVisibleSources().reduce((a, s) => a.concat(this._getTilesSpec({ x, y, zoom }, s)), [])
return new Promise((resolve, reject) => {
const canv = this.createTile()
const ctx = canv.getContext("2d")
const renderRef = this.mapboxRenderer.renderTiles(
ctx,
{
srcLeft: 0,
srcTop: 0,
width: this.tileSize,
height: this.tileSize,
destLeft: 0,
destTop: 0
},
tilesSpec,
(err) => {
/**
* In case of err ends with 'tiles not available', the canvas will still be painted.
* relate url: https://github.com/landtechnologies/Mapbox-vector-tiles-basic-js-renderer/blob/master/src/basic/renderer.js#L341-L405
*/
if (typeof err === "string" && !err.endsWith("tiles not available")) {
reject(undefined)
} else if (releaseTile) {
renderRef.consumer.ctx = undefined
resolve(canv)
// releaseTile默认为true对应Cesium请求图像的情形
this.mapboxRenderer.releaseRender(renderRef)
this.mapboxRenderer._style.sourceCaches?.origin?._tileCache.reset()
} else {
// releaseTile为false时在由pickFeature手动调用在渲染完成之后在pickFeature里边手动释放tile
resolve(renderRef)
}
}
)
})
}
pickFeatures(x, y, zoom, longitude, latitude) {
return this.requestImage(x, y, zoom, false).then((renderRef) => {
let targetSources = this.mapboxRenderer.getVisibleSources(zoom)
targetSources = this.sourceFilter ? this.sourceFilter(targetSources) : targetSources
const queryResult = []
longitude = Cesium.Math.toDegrees(longitude)
latitude = Cesium.Math.toDegrees(latitude)
targetSources.forEach((s) => {
const data = this.mapboxRenderer.queryRenderedFeatures({
source: s,
renderedZoom: zoom,
lng: longitude,
lat: latitude,
tileZ: zoom
})
for (const key in data) {
const item = data[key]
for (let index = 0; index < item.length; index++) {
const element = item[index]
element.layer = key
queryResult.push({ properties: element })
}
}
})
// release tile
renderRef.consumer.ctx = undefined
this.mapboxRenderer.releaseRender(renderRef)
this.mapboxRenderer._style.sourceCaches?.origin?._tileCache.reset()
return queryResult
})
}
destroy() {
this.mapboxRenderer._cancelAllPendingRenders()
Object.values(this.mapboxRenderer._style.sourceCaches).forEach((cache) => cache._tileCache.reset())
this.mapboxRenderer._gl.getExtension("WEBGL_lose_context").loseContext()
}
}
class PbfLayer extends mars3d.layer.BaseTileLayer {
// 构建ImageryProvider
async _createImageryProvider(options) {
return createImageryProvider(options)
}
}
async function createImageryProvider(options) {
if (options.url) {
let data = await Cesium.Resource.fetchJson(options)
const provider = new MVTImageryProvider({ ...options, style: data })
await provider.readyPromise
return provider
} else {
const provider = new MVTImageryProvider(options)
await provider.readyPromise
return provider
}
}
PbfLayer.createImageryProvider = createImageryProvider
// 注册下
const layerType = "pbf" // 图层类型
mars3d.LayerUtil.register(layerType, PbfLayer)
mars3d.LayerUtil.registerImageryProvider(layerType, createImageryProvider)
// 对外接口
window.mars3d.layer.PbfLayer = PbfLayer
})(window)
// export { PbfLayer }