53 lines
1.4 KiB
JavaScript
53 lines
1.4 KiB
JavaScript
goog.require('ol.Map');
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goog.require('ol.RendererHint');
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goog.require('ol.View2D');
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goog.require('ol.geom.MultiPoint');
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goog.require('ol.layer.Tile');
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goog.require('ol.shape');
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goog.require('ol.source.MapQuestOpenAerial');
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goog.require('ol.style.Fill');
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goog.require('ol.style.Stroke');
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var map = new ol.Map({
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layers: [
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new ol.layer.Tile({
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source: new ol.source.MapQuestOpenAerial()
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})
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],
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renderer: ol.RendererHint.CANVAS,
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target: 'map',
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view: new ol.View2D({
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center: [0, 0],
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zoom: 2
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})
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});
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map.beforeRender(function(map, frameState) {
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frameState.animate = true;
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return true;
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});
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var imageStyle = ol.shape.renderCircle(5,
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new ol.style.Fill({color: 'yellow'}),
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new ol.style.Stroke({color: 'red', width: 1}));
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var n = 200;
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var omegaTheta = 30000; // Rotation period in ms
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var R = 7e6;
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var r = 2e6;
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var p = 2e6;
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map.on('postcompose', function(event) {
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var render = event.getRender();
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var frameState = event.getFrameState();
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var theta = 2 * Math.PI * frameState.time / omegaTheta;
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var coordinates = [];
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var i;
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for (i = 0; i < n; ++i) {
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var t = theta + 2 * Math.PI * i / n;
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var x = (R + r) * Math.cos(t) + p * Math.cos((R + r) * t / r);
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var y = (R + r) * Math.sin(t) + p * Math.sin((R + r) * t / r);
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coordinates.push([x, y]);
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}
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render.setImageStyle(imageStyle);
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render.drawMultiPointGeometry(new ol.geom.MultiPoint(coordinates));
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});
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map.requestRenderFrame();
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