Dear Cesium users and team!
How to clamp to ground PointPrimitiveCollection?
I have tried this code in sandcastle, but it is not working 
var viewer = new Cesium.Viewer(‘cesiumContainer’, {
terrainProvider: Cesium.createWorldTerrain()
});
viewer.scene.globe.depthTestAgainstTerrain = true;
var points = viewer.scene.primitives.add(new Cesium.PointPrimitiveCollection({
heightReference : Cesium.HeightReference.CLAMP_TO_GROUND
}));
for (var longitude = -180; longitude < 180; longitude++) {
var color = Cesium.Color.PINK;
if ((longitude % 2) === 0) {
color = Cesium.Color.CYAN;
}
for (var latitude = -90; latitude < 90; latitude++) {
points.add({
position : Cesium.Cartesian3.fromDegrees(longitude, latitude),
color : color,
heightReference : Cesium.HeightReference.RELATIVE_TO_GROUND
});
}
}
Any help would be greatly appreciated.
Sincerely,
Ru