Files
openlayers/examples/mvtlayer.worker.js
2020-03-23 12:46:20 +01:00

76 lines
2.1 KiB
JavaScript

import VectorTileLayer from '../src/ol/layer/VectorTile.js';
import VectorTileSource from '../src/ol/source/VectorTile.js';
import MVT from '../src/ol/format/MVT.js';
import {Projection} from '../src/ol/proj.js';
import TileQueue from '../src/ol/TileQueue.js';
import {getTilePriority as tilePriorityFunction} from '../src/ol/TileQueue.js';
const key = 'pk.eyJ1IjoiYWhvY2V2YXIiLCJhIjoiY2pzbmg0Nmk5MGF5NzQzbzRnbDNoeHJrbiJ9.7_-_gL8ur7ZtEiNwRfCy7Q';
/** @type {any} */
const worker = self;
let frameState;
function getTilePriority(tile, tileSourceKey, tileCenter, tileResolution) {
return tilePriorityFunction(frameState, tile, tileSourceKey, tileCenter, tileResolution);
}
const layer = new VectorTileLayer({
declutter: true,
source: new VectorTileSource({
format: new MVT(),
url: 'https://{a-d}.tiles.mapbox.com/v4/mapbox.mapbox-streets-v6/' +
'{z}/{x}/{y}.vector.pbf?access_token=' + key
})
});
const tileQueue = new TileQueue(getTilePriority, function() {
worker.postMessage({type: 'render'});
});
const maxTotalLoading = 8;
const maxNewLoads = 2;
const renderer = layer.getRenderer();
renderer.useContainer = function(target, transform, opacity) {
target.style = {};
this.canvas = target;
this.context = target.getContext('2d');
this.container = {
firstElementChild: target
};
worker.postMessage({
type: 'transform-opacity',
transform: transform,
opacity: opacity
});
};
let canvas;
let rendering = false;
worker.onmessage = function(event) {
if (rendering) {
// drop this frame
return;
}
if (event.data.canvas) {
canvas = event.data.canvas;
} else {
frameState = event.data.frameState;
frameState.tileQueue = tileQueue;
frameState.viewState.projection.__proto__ = Projection.prototype;
rendering = true;
requestAnimationFrame(function() {
renderer.renderFrame(frameState, canvas);
if (tileQueue.getTilesLoading() < maxTotalLoading) {
tileQueue.reprioritize(); // FIXME only call if view has changed
tileQueue.loadMoreTiles(maxTotalLoading, maxNewLoads);
}
rendering = false;
});
}
};
export let create;