108 lines
4.0 KiB
HTML
108 lines
4.0 KiB
HTML
<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="utf-8">
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<meta http-equiv="X-UA-Compatible" content="IE=edge">
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<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no">
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<meta name="description" content="Use Viewer to start building new applications or easily embed Cesium into existing applications.">
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<meta name="cesium-sandcastle-labels" content="Beginner, Showcases">
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<title>Cesium Demo</title>
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<script type="text/javascript" src="../Sandcastle-header.js"></script>
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<script type="text/javascript" src="../../../ThirdParty/requirejs-2.1.20/require.js"></script>
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<script type="text/javascript">
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require.config({
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baseUrl : '../../../Source',
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waitSeconds : 60
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});
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</script>
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</head>
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<body class="sandcastle-loading" data-sandcastle-bucket="bucket-requirejs.html">
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<style>
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@import url(../templates/bucket.css);
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</style>
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<div id="cesiumContainer" class="fullSize"></div>
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<div id="loadingOverlay"><h1>Loading...</h1></div>
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<div id="toolbar"></div>
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<script id="cesium_sandcastle_script">
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function startup(Cesium) {
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'use strict';
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//Sandcastle_Begin
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// This example illustrates a Callback Property, a property whose
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// value is lazily evaluated by a callback function.
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// Use a CallbackProperty when your data can't be pre-computed
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// or needs to be derived from other properties at runtime.
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var viewer = new Cesium.Viewer('cesiumContainer');
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viewer.clock.shouldAnimate = true;
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var startLatitude = 35;
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var startLongitude = -120;
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var endLongitude;
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var startTime = Cesium.JulianDate.now();
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// Add a polyline to the scene. Positions are dynamic.
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var isConstant = false;
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var redLine = viewer.entities.add({
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polyline : {
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// This callback updates positions each frame.
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positions : new Cesium.CallbackProperty(function(time, result) {
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endLongitude = startLongitude + 0.001 * Cesium.JulianDate.secondsDifference(time, startTime);
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return Cesium.Cartesian3.fromDegreesArray([startLongitude, startLatitude, endLongitude, startLatitude], Cesium.Ellipsoid.WGS84, result);
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}, isConstant),
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width : 5,
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material : Cesium.Color.RED
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}
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});
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var startCartographic = Cesium.Cartographic.fromDegrees(startLongitude, startLatitude);
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// use scratch object to avoid new allocations per frame.
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var endCartographic = new Cesium.Cartographic();
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var scratch = new Cesium.Cartographic();
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var geodesic = new Cesium.EllipsoidGeodesic();
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// Calculate the length of the line
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function getLength(time, result) {
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// Get the end position from the polyLine's callback.
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var endPoint = redLine.polyline.positions.getValue(time, result)[1];
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endCartographic = Cesium.Cartographic.fromCartesian(endPoint);
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geodesic.setEndPoints(startCartographic, endCartographic);
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var lengthInMeters = Math.round(geodesic.surfaceDistance);
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return (lengthInMeters / 1000).toFixed(1) + ' km';
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}
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function getMidpoint(time, result) {
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// Get the end position from the polyLine's callback.
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var endPoint = redLine.polyline.positions.getValue(time, result)[1];
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endCartographic = Cesium.Cartographic.fromCartesian(endPoint);
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geodesic.setEndPoints(startCartographic, endCartographic);
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var midpointCartographic = geodesic.interpolateUsingFraction(0.5, scratch);
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return Cesium.Cartesian3.fromRadians(midpointCartographic.longitude, midpointCartographic.latitude);
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}
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// Label the polyline with calculated length.
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var label = viewer.entities.add({
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position : new Cesium.CallbackProperty(getMidpoint, isConstant),
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label : {
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// This callback updates the length to print each frame.
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text: new Cesium.CallbackProperty(getLength, isConstant),
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font : '20px sans-serif',
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pixelOffset : new Cesium.Cartesian2(0.0, 20)
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}
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});
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// Keep the view centered.
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viewer.trackedEntity = label;
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//Sandcastle_End
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Sandcastle.finishedLoading();
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}
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if (typeof Cesium !== 'undefined') {
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startup(Cesium);
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} else if (typeof require === 'function') {
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require(['Cesium'], startup);
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}
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</script>
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</body>
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</html>
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