CZML did reach track end callback

[jean-b...@easy-mountain.com]

1. A concise explanation of the problem you're experiencing.

I need to know when an entity reaches the end of its positions, to trigger some events.
I tried to use range: 'LOOP_STOP', but the animation starts again from the beginning.
I also tried to check if currentTime is greater than endDate, but as CZML is loaded asynchronously, I sometimes have a noticeable difference.

2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.

var czml = [{
id : 'document',
name : 'CZML Path',
version : '1.0',
clock: {
interval: startDate.toISOString() + '/' + endDate.toISOString(),
currentTime: startDate.toISOString(),
multiplier: 1,
range: 'LOOP_STOP',
}
}, {
id : 'path',
name : 'path data',
description : 'hike trace',
availability : startDate.toISOString() + '/' + endDate.toISOString(),
billboard : {
image : './data/images/Status/Orange-26x26.png'
},
position : {
epoch : startDate.toISOString(),
cartographicDegrees : []
}
}];

var coords = [];
for (var i=0; i<pathGeojson.geometry.coordinates.length; i++) {
var currentCoordinates = pathGeojson.geometry.coordinates[i];
coords = coords.concat(Cesium.Cartographic.fromDegrees(currentCoordinates[0], currentCoordinates[1]));
}

var promise = Cesium.sampleTerrainMostDetailed(Cesium.createWorldTerrain(), coords);
promise.then(function(updatedPositions) {

for (var i=0; i < pathGeojson.geometry.coordinates.length; i++) {
var coordinates = [i/timeDivider].concat(pathGeojson.geometry.coordinates[i].slice(0,2).concat(updatedPositions[i].height + 1));
czml[1].position.cartographicDegrees = czml[1].position.cartographicDegrees.concat(coordinates);
}

viewer.flyTo(layers.startMarkerLayer.entities.values[0])
.then(function() {
Cesium.CzmlDataSource.load(czml)
.then(
function(currentCZML) {
viewer.dataSources.add(currentCZML);
viewer.trackedEntity = currentCZML.entities.getById('path');
}
);
});

});

3. Context. Why do you need to do this? We might know a better way to accomplish your goal.

I have a button which will zoom on the first point of a polyline, then load it as a CZML to track it to the end. While the tracking is on, the start button is replaced with a stop button. If the tracking reaches the end before someone clicks the stop button, I want to stop the tracking manually, unload the CZML, and replace the stop button with a start button.

4. The Cesium version you're using, your operating system and browser.

Cesium 1.46, Safari 11.1.1, macOS 10.13.5

[Gabby Getz]

You can get the DataSourceClock associated with that DataSource once loaded, and get the stop time from that:

var stop = currentCZML.clock.stopTime;

Thanks,

Gabby