Clock control mechanism

CesiumJS
1

Hi folks,

I am trying to get my head around the Clock mechanism in Cesium. I think I am misunderstanding how it should work.

Basically
what I want is a clock which I control. I will set a start time and end time. Then when I load in CZML packets(objects) they will will be displayed if their availability corresponds to my clock current time. So
as I scroll through my timeline czml objects from different datasources
will appear and disappear according to my clock.

Scenario 1:
However so far what I am experiencing is the following.
I create a Cesium.Viewer. This has a clock associated with it. I can set the clock times etc as follows:

 viewer.clock.currentTime = now;

 viewer.clock.startTime = now.clone();
 viewer.clock.stopTime = now.addDays(1.0);     
 viewer.timeline.updateFromClock();

However
when I load in CZMl files they change the clock settings. In my CZML files I have not specified a clock. I have just specified an availability for each object. This is frustrating as I don’t want the CZML objects to drive the clock.

Scenario 2:

I set a clock in a CZMl file. I then load the file as follows:
var czmlDataSource = new Cesium.CzmlDataSource();
czmlDataSource.loadUrl(dataLocation + czmlFile).then(function() {

   viewer.dataSources.add(czmlDataSource);
   viewer.homeButton.viewModel.command();
});

For the next file I do as follows:

var czmlDataSource = new Cesium.CzmlDataSource();
    czmlDataSource.processUrl(dataLocation + czmlFile).then(function() {

viewer.dataSources.add(czmlDataSource);
        viewer.homeButton.viewModel.command();
});

However
the data from the second packet appears to overwrite the first. So the clock I see is always the second one. As I will have multiple files I want one clock independent of these CZML files (and associated clocks).

I saw in the forums one thread where the issue in the second scenario was encountered as follows:
https://groups.google.com/forum/#!searchin/cesium-dev/clock/cesium-dev/cNRs7pb_w1A/5ghJPwjKGg8J
It was suggested to build the application with CesiumWidget and create your own Clock instance. However I would prefer to use the Cesium.Viewer as I want to utilise the Cesium.viewerDynamicObjectMixin. Also I’m not sure how to associate the clock with the CesiumWidget in any event I cant seem to find any examples.

Anyone have any pointers for me. Thanks a mill.
Cheers Dave

2

Check the Viewer documentation for an option called “automaticallyTrackDataSourceClocks” that you can set to false.

–Ed.