scene.drillPick() hangs if picking out of more than 254 items

[rutsky]

Take look at the following example:

Cesium.Camera.DEFAULT_VIEW_RECTANGLE = Cesium.Rectangle.fromDegrees(-40, -40, 40, 40);

var viewer = new Cesium.Viewer('cesiumContainer', {
    selectionIndicator : false,
    infoBox : false
});

var scene = viewer.scene;
var handler;

var i;
for (i = 0; i != 255; ++i) {
    viewer.entities.add({
        id: 'obj_' + i,
        /*
        polyline: {
            positions: Cesium.Cartesian3.fromDegreesArray(
                [Math.random() * 10, Math.random() * 10, Math.random() * 10, Math.random() * 10]),
            followSurface: false,
            material: Cesium.Color.RED,
          },
        */
        point: {
            color: Cesium.Color.RED
        },
        position: Cesium.Cartesian3.fromDegrees(Math.random() * 10, Math.random() * 10)
    });
}

handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
handler.setInputAction(function(movement) {
    var pickedObjects = scene.drillPick(movement.endPosition);
    
    var ids = pickedObjects.map(function(obj) {return obj.id._id;});
    
    if (pickedObjects.length > 0) {
        var cartesian = viewer.camera.pickEllipsoid(movement.endPosition, scene.globe.ellipsoid);
        if (cartesian) {
            var cartographic = Cesium.Cartographic.fromCartesian(cartesian);
            var longitudeString = Cesium.Math.toDegrees(cartographic.longitude).toFixed(2);
            var latitudeString = Cesium.Math.toDegrees(cartographic.latitude).toFixed(2);
            
            console.log(movement.endPosition + ' (' + longitudeString + ', ' + latitudeString + ') - ' + ids);
        } else {
            console.log(movement.endPosition + ' - ' + ids);
        }
    }
}, Cesium.ScreenSpaceEventType.MOUSE_MOVE);

[rutsky]

This is based on example from #4783.
In #4783 points are being incorrectly selected which caused "false positives" in selection.
If same objects are not being picked, but drillPick-ed --- Cesium hangs.

Try to move mouse cursor near Earth sphere edge in the example above --- browser tab will hang.

Tested in CesiumJS 1.28 in Firefox Developer Edition 52.0a2 and Chromium 55.0.2883.87 on Ubuntu 16.04 with NVidia GTX 980 with NVidia proprietary drivers 367.57.

[hpinkos]

Thanks @rutsky, we'll try to take a look at this