HelloWorld.html

<!DOCTYPE html>
<html lang="en">
<head>
  <!-- Use correct character set. -->
  <meta charset="utf-8">
  <!-- Tell IE to use the latest, best version. -->
  <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">
  <title>Hello World!</title>
  <script src="../Build/Cesium/Cesium.js"></script>
  <style>
      @import url(../Build/Cesium/Widgets/widgets.css);
      html, body, #cesiumContainer {
          width: 100%; height: 100%; margin: 0; padding: 0; overflow: hidden;
      }
 
  </style>
</head>
<body>
<div id="cesiumContainer"></div>
<script>
var viewer = new Cesium.Viewer('cesiumContainer', {vrButton : true});

var ortho = new Cesium.UrlTemplateImageryProvider({ 
		url: './ortho/{z}/{x}/{reverseY}.png', 
});
viewer.scene.imageryLayers.addImageryProvider(ortho);
var terrainProvider = new Cesium.CesiumTerrainProvider({
    	url : './terrain',
	requestVertexNormals : true
});

viewer.terrainProvider = terrainProvider;


viewer.scene.globe.enableLighting = true;
viewer.scene.globe.depthTestAgainstTerrain = true;
Cesium.Math.setRandomNumberSeed(3);
var start = Cesium.JulianDate.fromDate(new Date(2016, 11, 20, 9));
var stop = Cesium.JulianDate.addSeconds(start, 360, new Cesium.JulianDate());
viewer.clock.startTime = start.clone();
viewer.clock.stopTime = stop.clone();
viewer.clock.currentTime = start.clone();
viewer.clock.clockRange = Cesium.ClockRange.LOOP_STOP;
viewer.clock.multiplier = 2.5;
viewer.timeline.zoomTo(start, stop);

function computeCirclularFlight(lon, lat, radius) {
    var property = new Cesium.SampledPositionProperty();
    for (var i = 0; i <= 360; i += 45) {
        var radians = Cesium.Math.toRadians(i);
        var time = Cesium.JulianDate.addSeconds(start, i, new Cesium.JulianDate());
        var position = Cesium.Cartesian3.fromDegrees(lon + (radius * 1.5 * Math.cos(radians)), lat + (radius * Math.sin(radians)), 1000);
        property.addSample(time, position);
        viewer.entities.add({
            position : position,
        });
    }
    return property;
}


var position = computeCirclularFlight(140.9445306, 38.2346564, 0.035);
var entity = viewer.entities.add({
    availability : new Cesium.TimeIntervalCollection([new Cesium.TimeInterval({
        start : start,
        stop : stop
    })]),
    position : position,
    orientation : new Cesium.VelocityOrientationProperty(position),   
});

entity.position.setInterpolationOptions({
    interpolationDegree : 2,
    interpolationAlgorithm : Cesium.HermitePolynomialApproximation
});

var camera = viewer.camera;
camera.position = new Cesium.Cartesian3(1.0, 1.0, 1.0);
camera.direction = new Cesium.Cartesian3(0.2, 1.0, -0.3);
camera.up = new Cesium.Cartesian3(0.0, 0.0, 1.0);
camera.right = new Cesium.Cartesian3(0.0, -1.0, 0.0);

viewer.scene.preRender.addEventListener(function(scene, time) {
    var position = entity.position.getValue(time);
    if (!Cesium.defined(position)) {
        return;
    }
    var transform;
    if (!Cesium.defined(entity.orientation)) {
        transform = Cesium.Transforms.eastNorthUpToFixedFrame(position);
    } else {
        var orientation = entity.orientation.getValue(time);
        if (!Cesium.defined(orientation)) {
            return;
        }
        transform = Cesium.Matrix4.fromRotationTranslation(Cesium.Matrix3.fromQuaternion(orientation), position);
    }
    var offset = Cesium.Cartesian3.clone(camera.position);
    var direction = Cesium.Cartesian3.clone(camera.direction);
    var up = Cesium.Cartesian3.clone(camera.up);
    camera.lookAtTransform(transform);
    Cesium.Cartesian3.clone(offset, camera.position);
    Cesium.Cartesian3.clone(direction, camera.direction);
    Cesium.Cartesian3.clone(up, camera.up);
    Cesium.Cartesian3.cross(direction, up, camera.right);
});

</script>
</body>
</html>