Here what I got at the moment
Copy/paste code below into Cesium/Sandcastle editor and run:
var cesiumViewer = new Cesium.Viewer('cesiumContainer',
{
terrainProvider: new Cesium.CesiumTerrainProvider({ url: '//assets.agi.com/stk-terrain/world' })
, baseLayerPicker: false
});
drawPolylineOnTerrain();
function drawPolylineOnTerrain() {
var polylinePoints =
[
{lng:150.644, lat:-34.397},
{lng:150.644, lat:-35.397},
{lng:156.644, lat:-35.397},
{lng:156.644, lat:-36.397},
{lng:158.644, lat:-37.397},
{lng:160.644, lat:-39.397}
];
var polylinePointsExtended = extendWithIntermediatePoints(polylinePoints);
Cesium.when(Cesium.sampleTerrain(cesiumViewer.terrainProvider, 9, polylinePointsExtended), sampleTerrainSuccess);
}
function extendWithIntermediatePoints(polylinePoints) {
var extendedPoints = ;
var previousPoint = polylinePoints[0];
extendedPoints.push(Cesium.Cartographic.fromDegrees(previousPoint.lng, previousPoint.lat));
var minDistance = 0.001;
for (var i = 1; i < polylinePoints.length; i++) {
var current = polylinePoints[i];
var lngDiff = current.lng - previousPoint.lng;
var latDiff = current.lat - previousPoint.lat;
var max = Math.max(Math.abs(lngDiff), Math.abs(latDiff));
var pointCount = parseInt(max / minDistance, 10);
var lngIncrement = lngDiff / (pointCount ? pointCount : 1);
var latIncrement = latDiff / (pointCount ? pointCount : 1);
var count = 1;
while (count <= pointCount) {
extendedPoints.push(Cesium.Cartographic.fromDegrees(previousPoint.lng + count * lngIncrement, previousPoint.lat + count * latIncrement));
count++;
}
extendedPoints.push(Cesium.Cartographic.fromDegrees(current.lng, current.lat));
previousPoint = current;
}
return extendedPoints;
}
function sampleTerrainSuccess(sampleTerrainPoints) {
var updatedPolyLinePoints = ;
for (var i = 0; i < sampleTerrainPoints.length; ++i) {
var updatedPoint = sampleTerrainPoints[i];
updatedPolyLinePoints.push(Cesium.Math.toDegrees(updatedPoint.longitude), Cesium.Math.toDegrees(updatedPoint.latitude), updatedPoint.height);
}
function computeCircle(radius) {
var positions = ;
for (var i = 0; i < 360; i++) {
var radians = Cesium.Math.toRadians(i);
positions.push(new Cesium.Cartesian2(radius * Math.cos(radians), radius * Math.sin(radians)));
}
return positions;
}
cesiumViewer.entities.add({
//polylineVolume:
polyline: {
positions: Cesium.Cartesian3.fromDegreesArrayHeights(updatedPolyLinePoints),
//shape :computeCircle(1000),
width:5,
material: Cesium.Color.BLACK
}
});
cesiumViewer.zoomTo(cesiumViewer.entities);
}
