DSDSServer2024/build/build.20240805/static/js/Cesium-1.53/Specs/DataSources/PathVisualizerSpec.js

defineSuite([
        'DataSources/PathVisualizer',
        'Core/Cartesian3',
        'Core/Color',
        'Core/DistanceDisplayCondition',
        'Core/JulianDate',
        'Core/Matrix4',
        'Core/ReferenceFrame',
        'Core/TimeInterval',
        'DataSources/CompositePositionProperty',
        'DataSources/ConstantPositionProperty',
        'DataSources/ConstantProperty',
        'DataSources/EntityCollection',
        'DataSources/PathGraphics',
        'DataSources/PolylineGlowMaterialProperty',
        'DataSources/PolylineOutlineMaterialProperty',
        'DataSources/ReferenceProperty',
        'DataSources/SampledPositionProperty',
        'DataSources/ScaledPositionProperty',
        'DataSources/TimeIntervalCollectionPositionProperty',
        'Scene/SceneMode',
        'Specs/createScene'
    ], function(
        PathVisualizer,
        Cartesian3,
        Color,
        DistanceDisplayCondition,
        JulianDate,
        Matrix4,
        ReferenceFrame,
        TimeInterval,
        CompositePositionProperty,
        ConstantPositionProperty,
        ConstantProperty,
        EntityCollection,
        PathGraphics,
        PolylineGlowMaterialProperty,
        PolylineOutlineMaterialProperty,
        ReferenceProperty,
        SampledPositionProperty,
        ScaledPositionProperty,
        TimeIntervalCollectionPositionProperty,
        SceneMode,
        createScene) {
    'use strict';

    var scene;
    var visualizer;

    beforeAll(function() {
        scene = createScene();
    });

    afterAll(function() {
        scene.destroyForSpecs();
    });

    afterEach(function() {
        visualizer = visualizer && visualizer.destroy();
    });

    it('constructor throws if no scene is passed.', function() {
        expect(function() {
            return new PathVisualizer();
        }).toThrowDeveloperError();
    });

    it('update throws if no time specified.', function() {
        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);
        expect(function() {
            visualizer.update();
        }).toThrowDeveloperError();
    });

    it('isDestroy returns false until destroyed.', function() {
        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);
        expect(visualizer.isDestroyed()).toEqual(false);
        visualizer.destroy();
        expect(visualizer.isDestroyed()).toEqual(true);
        visualizer = undefined;
    });

    it('removes the listener from the entity collection when destroyed', function() {
        var entityCollection = new EntityCollection();
        var visualizer = new PathVisualizer(scene, entityCollection);
        expect(entityCollection.collectionChanged.numberOfListeners).toEqual(1);
        visualizer.destroy();
        expect(entityCollection.collectionChanged.numberOfListeners).toEqual(0);
    });

    it('object with no path does not create one.', function() {
        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);

        var testObject = entityCollection.getOrCreateEntity('test');
        testObject.position = new ConstantProperty([new Cartesian3(1234, 5678, 9101112), new Cartesian3(5678, 1234, 1101112)]);
        visualizer.update(JulianDate.now());
        expect(scene.primitives.length).toEqual(0);
    });

    it('object with no position does not create a polyline.', function() {
        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);

        var testObject = entityCollection.getOrCreateEntity('test');
        var path = testObject.path = new PathGraphics();
        path.show = new ConstantProperty(true);

        visualizer.update(JulianDate.now());
        expect(scene.primitives.length).toEqual(0);
    });

    it('adding and removing an entity path without rendering does not crash.', function() {
        var times = [new JulianDate(0, 0), new JulianDate(1, 0)];
        var positions = [new Cartesian3(1234, 5678, 9101112), new Cartesian3(5678, 1234, 1101112)];

        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);

        var position = new SampledPositionProperty();
        position.addSamples(times, positions);

        var testObject = entityCollection.getOrCreateEntity('test');
        testObject.position = position;
        testObject.path = new PathGraphics();

        //Before we fixed the issue, the below remove call would cause a crash
        //when visualizer.update was not called at least once after the entity was added.
        entityCollection.remove(testObject);
    });

    it('A PathGraphics causes a primitive to be created and updated.', function() {
        var times = [new JulianDate(0, 0), new JulianDate(1, 0)];
        var updateTime = new JulianDate(0.5, 0);
        var positions = [new Cartesian3(1234, 5678, 9101112), new Cartesian3(5678, 1234, 1101112)];

        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);

        expect(scene.primitives.length).toEqual(0);

        var testObject = entityCollection.getOrCreateEntity('test');
        var position = new SampledPositionProperty();
        testObject.position = position;
        position.addSamples(times, positions);

        var path = testObject.path = new PathGraphics();
        path.show = new ConstantProperty(true);
        path.material = new PolylineOutlineMaterialProperty();
        path.material.color = new ConstantProperty(new Color(0.8, 0.7, 0.6, 0.5));
        path.material.outlineColor = new ConstantProperty(new Color(0.1, 0.2, 0.3, 0.4));
        path.material.outlineWidth = new ConstantProperty(2.5);
        path.width = new ConstantProperty(12.5);
        path.distanceDisplayCondition = new ConstantProperty(new DistanceDisplayCondition(10.0, 20.0));
        path.leadTime = new ConstantProperty(25);
        path.trailTime = new ConstantProperty(10);

        visualizer.update(updateTime);

        expect(scene.primitives.length).toEqual(1);

        var polylineCollection = scene.primitives.get(0);
        var primitive = polylineCollection.get(0);
        expect(primitive.positions[0]).toEqual(testObject.position.getValue(JulianDate.addSeconds(updateTime, -path.trailTime.getValue(), new JulianDate())));
        expect(primitive.positions[1]).toEqual(testObject.position.getValue(updateTime));
        expect(primitive.positions[2]).toEqual(testObject.position.getValue(JulianDate.addSeconds(updateTime, path.leadTime.getValue(), new JulianDate())));
        expect(primitive.show).toEqual(testObject.path.show.getValue(updateTime));
        expect(primitive.width).toEqual(testObject.path.width.getValue(updateTime));
        expect(primitive.distanceDisplayCondition).toEqual(testObject.path.distanceDisplayCondition.getValue(updateTime));

        var material = primitive.material;
        expect(material.uniforms.color).toEqual(testObject.path.material.color.getValue(updateTime));
        expect(material.uniforms.outlineColor).toEqual(testObject.path.material.outlineColor.getValue(updateTime));
        expect(material.uniforms.outlineWidth).toEqual(testObject.path.material.outlineWidth.getValue(updateTime));

        path.show = new ConstantProperty(false);
        visualizer.update(updateTime);
        expect(primitive.show).toEqual(testObject.path.show.getValue(updateTime));
    });

    it('creates primitives when an entity is already in the collection.', function() {
        var times = [new JulianDate(0, 0), new JulianDate(1, 0)];
        var updateTime = new JulianDate(0.5, 0);
        var positions = [new Cartesian3(1234, 5678, 9101112), new Cartesian3(5678, 1234, 1101112)];

        var entityCollection = new EntityCollection();

        var testObject = entityCollection.getOrCreateEntity('test');
        var position = new SampledPositionProperty();
        testObject.position = position;
        position.addSamples(times, positions);

        var path = testObject.path = new PathGraphics();
        path.show = new ConstantProperty(true);
        path.material = new PolylineOutlineMaterialProperty();
        path.material.color = new ConstantProperty(new Color(0.8, 0.7, 0.6, 0.5));
        path.material.outlineColor = new ConstantProperty(new Color(0.1, 0.2, 0.3, 0.4));
        path.material.outlineWidth = new ConstantProperty(2.5);
        path.width = new ConstantProperty(12.5);
        path.leadTime = new ConstantProperty(25);
        path.trailTime = new ConstantProperty(10);

        visualizer = new PathVisualizer(scene, entityCollection);

        expect(scene.primitives.length).toEqual(0);

        visualizer.update(updateTime);

        expect(scene.primitives.length).toEqual(1);
    });

    it('A custom material can be used.', function() {
        var times = [new JulianDate(0, 0), new JulianDate(1, 0)];
        var updateTime = new JulianDate(0.5, 0);
        var positions = [new Cartesian3(1234, 5678, 9101112), new Cartesian3(5678, 1234, 1101112)];

        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);

        expect(scene.primitives.length).toEqual(0);

        var testObject = entityCollection.getOrCreateEntity('test');
        var position = new SampledPositionProperty();
        testObject.position = position;
        position.addSamples(times, positions);

        var path = testObject.path = new PathGraphics();
        path.show = new ConstantProperty(true);
        path.material = new PolylineGlowMaterialProperty();
        path.material.color = new ConstantProperty(new Color(0.8, 0.7, 0.6, 0.5));
        path.material.glowPower = new ConstantProperty(0.2);
        path.width = new ConstantProperty(12.5);
        path.leadTime = new ConstantProperty(25);
        path.trailTime = new ConstantProperty(10);

        visualizer.update(updateTime);

        expect(scene.primitives.length).toEqual(1);

        var polylineCollection = scene.primitives.get(0);
        var primitive = polylineCollection.get(0);

        var material = primitive.material;
        expect(material.uniforms.color).toEqual(testObject.path.material.color.getValue(updateTime));
        expect(material.uniforms.glowPower).toEqual(testObject.path.material.glowPower.getValue(updateTime));
    });

    it('Reuses primitives when hiding one and showing another', function() {
        var times = [new JulianDate(0, 0), new JulianDate(1, 0)];
        var time = new JulianDate(0.5, 0);
        var positions = [new Cartesian3(1234, 5678, 9101112), new Cartesian3(5678, 1234, 1101112)];

        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);

        var position = new SampledPositionProperty();
        position.addSamples(times, positions);

        var testObject = entityCollection.getOrCreateEntity('test');
        testObject.position = position;
        testObject.path = new PathGraphics();
        testObject.path.show = new ConstantProperty(true);
        testObject.path.leadTime = new ConstantProperty(25);
        testObject.path.trailTime = new ConstantProperty(10);

        visualizer.update(time);

        var polylineCollection = scene.primitives.get(0);
        expect(polylineCollection.length).toEqual(1);

        testObject.path.show = new ConstantProperty(false);

        visualizer.update(time);

        expect(polylineCollection.length).toEqual(1);

        position = new SampledPositionProperty();
        position.addSamples(times, positions);

        var testObject2 = entityCollection.getOrCreateEntity('test2');
        testObject2.position = position;
        testObject2.path = new PathGraphics();
        testObject2.path.show = new ConstantProperty(true);
        testObject2.path.leadTime = new ConstantProperty(25);
        testObject2.path.trailTime = new ConstantProperty(10);

        visualizer.update(time);
        expect(polylineCollection.length).toEqual(1);
    });

    it('Switches from inertial to fixed paths in 2D', function() {
        var times = [new JulianDate(0, 0), new JulianDate(1, 0)];
        var time = new JulianDate(0.5, 0);
        var positions = [new Cartesian3(1234, 5678, 9101112), new Cartesian3(5678, 1234, 1101112)];

        var position = new SampledPositionProperty(ReferenceFrame.INERTIAL);
        position.addSamples(times, positions);

        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);
        var testObject = entityCollection.getOrCreateEntity('test');
        testObject.position = position;
        testObject.path = new PathGraphics();
        testObject.path.leadTime = new ConstantProperty(25);
        testObject.path.trailTime = new ConstantProperty(10);

        visualizer.update(time);

        expect(scene.primitives.length).toEqual(1);

        //They'll be one inertial polyline collection
        var inertialPolylineCollection = scene.primitives.get(0);
        expect(inertialPolylineCollection.length).toEqual(1);
        expect(inertialPolylineCollection.modelMatrix).not.toEqual(Matrix4.IDENTITY);

        var inertialLine = inertialPolylineCollection.get(0);
        expect(inertialLine.show).toEqual(true);

        scene.mode = SceneMode.SCENE2D;
        visualizer.update(time);

        //They'll be one inertial polyline collection (with no visible lines)
        //and a new fixed polyline collection.
        expect(scene.primitives.length).toEqual(2);

        var fixedPolylineCollection = scene.primitives.get(1);

        expect(inertialLine.show).toEqual(false);
        expect(fixedPolylineCollection.length).toEqual(1);
        expect(fixedPolylineCollection.modelMatrix).toEqual(Matrix4.IDENTITY);

        var fixedLine = fixedPolylineCollection.get(0);
        expect(fixedLine.show).toEqual(true);
    });

    it('clear hides primitives.', function() {
        var times = [new JulianDate(0, 0), new JulianDate(1, 0)];
        var updateTime = new JulianDate(0.5, 0);
        var positions = [new Cartesian3(1234, 5678, 9101112), new Cartesian3(5678, 1234, 1101112)];

        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);

        expect(scene.primitives.length).toEqual(0);

        var testObject = entityCollection.getOrCreateEntity('test');
        var position = new SampledPositionProperty();
        testObject.position = position;
        position.addSamples(times, positions);

        var path = testObject.path = new PathGraphics();
        path.show = new ConstantProperty(true);
        path.color = new ConstantProperty(new Color(0.8, 0.7, 0.6, 0.5));
        path.width = new ConstantProperty(12.5);
        path.outlineColor = new ConstantProperty(new Color(0.1, 0.2, 0.3, 0.4));
        path.outlineWidth = new ConstantProperty(2.5);
        path.leadTime = new ConstantProperty(25);
        path.trailTime = new ConstantProperty(10);

        visualizer.update(updateTime);

        expect(scene.primitives.length).toEqual(1);

        var polylineCollection = scene.primitives.get(0);
        var primitive = polylineCollection.get(0);

        visualizer.update(updateTime);
        //Clearing won't actually remove the primitive because of the
        //internal cache used by the visualizer, instead it just hides it.
        entityCollection.removeAll();
        expect(primitive.show).toEqual(false);
        expect(primitive.id).toBeUndefined();
    });

    it('Visualizer sets entity property.', function() {
        var times = [new JulianDate(0, 0), new JulianDate(1, 0)];
        var updateTime = new JulianDate(0.5, 0);
        var positions = [new Cartesian3(1234, 5678, 9101112), new Cartesian3(5678, 1234, 1101112)];

        var entityCollection = new EntityCollection();
        visualizer = new PathVisualizer(scene, entityCollection);

        expect(scene.primitives.length).toEqual(0);

        var testObject = entityCollection.getOrCreateEntity('test');
        var position = new SampledPositionProperty();
        testObject.position = position;
        position.addSamples(times, positions);

        var path = testObject.path = new PathGraphics();
        path.show = new ConstantProperty(true);
        path.color = new ConstantProperty(new Color(0.8, 0.7, 0.6, 0.5));
        path.width = new ConstantProperty(12.5);
        path.outlineColor = new ConstantProperty(new Color(0.1, 0.2, 0.3, 0.4));
        path.outlineWidth = new ConstantProperty(2.5);
        path.leadTime = new ConstantProperty(25);
        path.trailTime = new ConstantProperty(10);

        visualizer.update(updateTime);
        var polylineCollection = scene.primitives.get(0);
        var primitive = polylineCollection.get(0);
        expect(primitive.id).toEqual(testObject);
    });

    it('subSample works for constant properties', function() {
        var property = new ConstantPositionProperty(new Cartesian3(1000, 2000, 3000));
        var start = new JulianDate(0, 0);
        var stop = new JulianDate(1, 0);
        var updateTime = new JulianDate(1, 43200);
        var referenceFrame = ReferenceFrame.FIXED;
        var maximumStep = 10;
        var result = PathVisualizer._subSample(property, start, stop, updateTime, referenceFrame, maximumStep);
        expect(result).toEqual([property._value]);
    });

    it('subSample works for reference properties', function() {
        var property = new ConstantPositionProperty(new Cartesian3(1000, 2000, 3000));
        var start = new JulianDate(0, 0);
        var stop = new JulianDate(1, 0);
        var updateTime = new JulianDate(1, 43200);
        var referenceFrame = ReferenceFrame.FIXED;
        var maximumStep = 10;

        var entities = new EntityCollection();
        var targetEntity = entities.getOrCreateEntity('target');
        targetEntity.position = property;

        var referenceProperty = new ReferenceProperty(entities, 'target', ['position']);

        var result = PathVisualizer._subSample(referenceProperty, start, stop, updateTime, referenceFrame, maximumStep);
        expect(result).toEqual([property._value]);
    });

    it('subSample works for sampled properties', function() {
        var property = new SampledPositionProperty();

        var start = new JulianDate(0, 0);
        var stop = new JulianDate(1, 0);

        property.addSample(start, new Cartesian3(0, 0, 0));
        property.addSample(stop, new Cartesian3(0, 0, 100));

        var updateTime = new JulianDate(0, 43200);
        var referenceFrame = ReferenceFrame.FIXED;
        var maximumStep = 86400;
        var result = [];

        //A large maximum step causes no sub-smapling.
        PathVisualizer._subSample(property, start, stop, updateTime, referenceFrame, maximumStep, result);
        expect(result).toEqual([property.getValue(start), property.getValue(updateTime), property.getValue(stop)]);

        //An evenly spaced maximum step causes equal steps from start to stop
        maximumStep = 28800;
        var expectedStep = 28800;
        PathVisualizer._subSample(property, start, stop, updateTime, referenceFrame, maximumStep, result);
        expect(result).toEqual([property.getValue(start), property.getValue(JulianDate.addSeconds(start, expectedStep, new JulianDate())), property.getValue(updateTime), property.getValue(JulianDate.addSeconds(start, expectedStep * 2, new JulianDate())), property.getValue(stop)]);

        //An maximum step size that is slightly more than halfway between points causes a single step halfway between points
        maximumStep = 43201;
        expectedStep = 43200;
        updateTime = new JulianDate(0, 64800);
        PathVisualizer._subSample(property, start, stop, updateTime, referenceFrame, maximumStep, result);
        expect(result).toEqual([property.getValue(start), property.getValue(JulianDate.addSeconds(start, expectedStep, new JulianDate())), property.getValue(updateTime), property.getValue(stop)]);

        //An maximum step size that is slightly less than halfway between points causes two steps of the eqaul size to be taken between points
        maximumStep = 43199;
        expectedStep = 28800;
        updateTime = new JulianDate(0, 21600);
        PathVisualizer._subSample(property, start, stop, updateTime, referenceFrame, maximumStep, result);
        expect(result).toEqual([property.getValue(start), property.getValue(updateTime), property.getValue(JulianDate.addSeconds(start, expectedStep, new JulianDate())), property.getValue(JulianDate.addSeconds(start, expectedStep * 2, new JulianDate())), property.getValue(stop)]);
    });

    it('subSample works for interval properties', function() {
        var t1 = new JulianDate(0, 0);
        var t2 = new JulianDate(1, 0);
        var t3 = new JulianDate(2, 0);
        var t4 = new JulianDate(3, 0);

        var property = new TimeIntervalCollectionPositionProperty();
        property.intervals.addInterval(new TimeInterval({
            start : t1,
            stop : t2,
            data : new Cartesian3(0, 0, 1)
        }));
        property.intervals.addInterval(new TimeInterval({
            start : t2,
            stop : t3,
            isStartIncluded : false,
            isStopIncluded : false,
            data : new Cartesian3(0, 0, 2)
        }));
        property.intervals.addInterval(new TimeInterval({
            start : t3,
            stop : t4,
            data : new Cartesian3(0, 0, 3)
        }));

        var updateTime = new JulianDate(1, 43200);
        var referenceFrame = ReferenceFrame.FIXED;
        var maximumStep = 10;
        var result = [];
        PathVisualizer._subSample(property, t1, t4, updateTime, referenceFrame, maximumStep, result);
        expect(result).toEqual([new Cartesian3(0, 0, 1), new Cartesian3(0, 0, 2), new Cartesian3(0, 0, 3)]);

        PathVisualizer._subSample(property, t2, t3, updateTime, referenceFrame, maximumStep, result);
        expect(result).toEqual([new Cartesian3(0, 0, 1), new Cartesian3(0, 0, 2), new Cartesian3(0, 0, 3)]);

        PathVisualizer._subSample(property, t1, t2, updateTime, referenceFrame, maximumStep, result);
        expect(result).toEqual([new Cartesian3(0, 0, 1)]);

        PathVisualizer._subSample(property, t3, t4, updateTime, referenceFrame, maximumStep, result);
        expect(result).toEqual([new Cartesian3(0, 0, 3)]);
    });

    function CustomPositionProperty(innerProperty) {
        this.SampledProperty = innerProperty;
        this.isConstant = innerProperty.isConstant;
        this.definitionChanged = innerProperty.definitionChanged;
        this.referenceFrame = innerProperty.referenceFrame;

        this.getValue = function(time, result) {
            return innerProperty.getValue(time, result);
        };

        this.getValueInReferenceFrame = function(time, referenceFrame, result) {
            return innerProperty.getValueInReferenceFrame(time, referenceFrame, result);
        };

        this.equals = function(other) {
            return innerProperty.equals(other);
        };
    }

    it('subSample works for custom properties', function() {
        var t1 = new JulianDate(0, 0);
        var t2 = new JulianDate(1, 0);
        var t3 = new JulianDate(2, 0);
        var t4 = new JulianDate(3, 0);
        var updateTime = new JulianDate(1, 1);

        var sampledProperty = new SampledPositionProperty();
        sampledProperty.addSample(t1, new Cartesian3(0, 0, 1));
        sampledProperty.addSample(t2, new Cartesian3(0, 0, 2));
        sampledProperty.addSample(t3, new Cartesian3(0, 0, 3));
        sampledProperty.addSample(t4, new Cartesian3(0, 0, 4));

        var property = new CustomPositionProperty(sampledProperty);

        var referenceFrame = ReferenceFrame.FIXED;
        var maximumStep = 43200;
        var result = [];
        PathVisualizer._subSample(property, t1, t4, updateTime, referenceFrame, maximumStep, result);
        expect(result).toEqual([sampledProperty.getValue(t1), sampledProperty.getValue(JulianDate.addSeconds(t1, maximumStep, new JulianDate())), sampledProperty.getValue(JulianDate.addSeconds(t1, maximumStep * 2, new JulianDate())), sampledProperty.getValue(updateTime), sampledProperty.getValue(JulianDate.addSeconds(t1, maximumStep * 3, new JulianDate())), sampledProperty.getValue(JulianDate.addSeconds(t1, maximumStep * 4, new JulianDate())), sampledProperty.getValue(JulianDate.addSeconds(t1, maximumStep * 5, new JulianDate())), sampledProperty.getValue(JulianDate.addSeconds(t1, maximumStep * 6, new JulianDate()))]);
    });

    function createCompositeTest(useReferenceProperty){
        var t1 = new JulianDate(0, 0);
        var t2 = new JulianDate(1, 0);
        var t3 = new JulianDate(2, 0);
        var t4 = new JulianDate(3, 0);
        var t5 = new JulianDate(4, 0);
        var t6 = new JulianDate(5, 0);

        var constantProperty = new ConstantPositionProperty(new Cartesian3(0, 0, 1));

        var intervalProperty = new TimeIntervalCollectionPositionProperty();
        intervalProperty.intervals.addInterval(new TimeInterval({
            start : t1,
            stop : t2,
            data : new Cartesian3(0, 0, 1)
        }));
        intervalProperty.intervals.addInterval(new TimeInterval({
            start : t2,
            stop : t3,
            isStartIncluded : false,
            isStopIncluded : false,
            data : new Cartesian3(0, 0, 2)
        }));
        intervalProperty.intervals.addInterval(new TimeInterval({
            start : t1,
            stop : t2,
            data : new Cartesian3(0, 0, 3)
        }));

        var sampledProperty = new SampledPositionProperty();
        sampledProperty.addSample(t1, new Cartesian3(0, 0, 1));
        sampledProperty.addSample(t2, new Cartesian3(0, 0, 2));
        sampledProperty.addSample(t3, new Cartesian3(0, 0, 3));
        sampledProperty.addSample(t4, new Cartesian3(0, 0, 4));

        var entities = new EntityCollection();
        var targetEntity = entities.getOrCreateEntity('target');
        targetEntity.position = new ConstantPositionProperty(new Cartesian3(0, 0, 5));
        var referenceProperty = new ReferenceProperty(entities, 'target', ['position']);

        var scaledProperty = new ScaledPositionProperty(referenceProperty);

        var property = new CompositePositionProperty();
        property.intervals.addInterval(new TimeInterval({
            start : t1,
            stop : t2,
            data : intervalProperty
        }));
        property.intervals.addInterval(new TimeInterval({
            start : t2,
            stop : t3,
            isStartIncluded : false,
            isStopIncluded : false,
            data : constantProperty
        }));
        property.intervals.addInterval(new TimeInterval({
            start : t3,
            stop : t4,
            data : sampledProperty
        }));
        property.intervals.addInterval(new TimeInterval({
            start : t4,
            stop : t5,
            isStartIncluded : false,
            isStopIncluded : true,
            data : referenceProperty
        }));
        property.intervals.addInterval(new TimeInterval({
            start : t5,
            stop : t6,
            isStartIncluded : false,
            isStopIncluded : true,
            data : scaledProperty
        }));

        var updateTime = new JulianDate(0, 0);
        var referenceFrame = ReferenceFrame.FIXED;
        var maximumStep = 43200;
        var result = [];

        var propertyToTest = property;
        if (useReferenceProperty) {
            var testReference = entities.getOrCreateEntity('testReference');
            testReference.position = property;
            propertyToTest = new ReferenceProperty(entities, 'testReference', ['position']);
        }

        PathVisualizer._subSample(propertyToTest, t1, t6, updateTime, referenceFrame, maximumStep, result);
        expect(result).toEqual([intervalProperty.intervals.get(0).data,
                                constantProperty.getValue(t1),
                                sampledProperty.getValue(t3),
                                sampledProperty.getValue(JulianDate.addSeconds(t3, maximumStep, new JulianDate())),
                                sampledProperty.getValue(t4),
                                targetEntity.position.getValue(t5),
                                scaledProperty.getValue(t6)]);
    }

    it('subSample works for composite properties', function() {
        createCompositeTest(false);
    });

    it('subSample works for composite properties wrapped in reference properties', function() {
        createCompositeTest(true);
    });

}, 'WebGL');