133 lines
4.8 KiB
HTML
133 lines
4.8 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
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name="viewport"
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content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no"
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/>
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<meta
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name="description"
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content="Use Viewer to start building new applications or easily embed Cesium into existing applications."
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/>
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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
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type="text/javascript"
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src="../../../Build/CesiumUnminified/Cesium.js"
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nomodule
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></script>
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<script type="module" src="../load-cesium-es6.js"></script>
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</head>
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<body
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class="sandcastle-loading"
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data-sandcastle-bucket="bucket-requirejs.html"
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>
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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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window.startup = async function (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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const viewer = new Cesium.Viewer("cesiumContainer");
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viewer.clock.shouldAnimate = true;
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const startLatitude = 35;
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const startLongitude = -120;
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let endLongitude;
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const startTime = Cesium.JulianDate.now();
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// Add a polyline to the scene. Positions are dynamic.
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const isConstant = false;
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const 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 =
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startLongitude +
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0.001 * Cesium.JulianDate.secondsDifference(time, startTime);
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return Cesium.Cartesian3.fromDegreesArray(
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[startLongitude, startLatitude, endLongitude, startLatitude],
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Cesium.Ellipsoid.WGS84,
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result
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);
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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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const startCartographic = Cesium.Cartographic.fromDegrees(
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startLongitude,
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startLatitude
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);
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// use scratch object to avoid new allocations per frame.
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let endCartographic = new Cesium.Cartographic();
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const scratch = new Cesium.Cartographic();
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const 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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const 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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const 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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const 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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const midpointCartographic = geodesic.interpolateUsingFraction(
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0.5,
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scratch
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);
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return Cesium.Cartesian3.fromRadians(
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midpointCartographic.longitude,
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midpointCartographic.latitude
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);
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}
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// Label the polyline with calculated length.
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const 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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};
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if (typeof Cesium !== "undefined") {
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window.startupCalled = true;
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window.startup(Cesium).catch((error) => {
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"use strict";
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console.error(error);
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});
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Sandcastle.finishedLoading();
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}
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</script>
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</body>
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</html>
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