Fix ground polyline with dynamic color

CHANGES.md

@@ -34,6 +34,7 @@ Change Log
 * Fixed a crash when setting show to `false` on a polyline clamped to the ground. [#6912](https://github.com/AnalyticalGraphicsInc/cesium/issues/6912)
 * Fixed crash that happened when calling `scene.pick` after setting a new terrain provider [#6918](https://github.com/AnalyticalGraphicsInc/cesium/pull/6918)
 * Fixed an issue that caused the browser to hang when using `drillPick` on a polyline clamped to the ground. [6907](https://github.com/AnalyticalGraphicsInc/cesium/issues/6907)
+* Fixed an issue where color wasn't updated propertly for polylines clamped to ground [#6927](https://github.com/AnalyticalGraphicsInc/cesium/pull/6927)
 
 ### 1.48 - 2018-08-01
 

Source/DataSources/StaticGroundPolylinePerMaterialBatch.js

@@ -1,5 +1,7 @@
 define([
         '../Core/AssociativeArray',
+        '../Core/Color',
+        '../Core/ColorGeometryInstanceAttribute',
         '../Core/defined',
         '../Core/DistanceDisplayCondition',
         '../Core/DistanceDisplayConditionGeometryInstanceAttribute',
@@ -13,6 +15,8 @@ define([
         './Property'
     ], function(
         AssociativeArray,
+        Color,
+        ColorGeometryInstanceAttribute,
         defined,
         DistanceDisplayCondition,
         DistanceDisplayConditionGeometryInstanceAttribute,
@@ -26,6 +30,7 @@ define([
         Property) {
     'use strict';
 
+    var scratchColor = new Color();
     var distanceDisplayConditionScratch = new DistanceDisplayCondition();
     var defaultDistanceDisplayCondition = new DistanceDisplayCondition();
 
@@ -195,6 +200,15 @@ define([
                     this.attributes.set(instance.id.id, attributes);
                 }
 
+                if (!updater.fillMaterialProperty.isConstant) {
+                    var colorProperty = updater.fillMaterialProperty.color;
+                    var resultColor = Property.getValueOrDefault(colorProperty, time, Color.WHITE, scratchColor);
+                    if (!Color.equals(attributes._lastColor, resultColor)) {
+                        attributes._lastColor = Color.clone(resultColor, attributes._lastColor);
+                        attributes.color = ColorGeometryInstanceAttribute.toValue(resultColor, attributes.color);
+                    }
+                }
+
                 var show = entity.isShowing && (updater.hasConstantFill || updater.isFilled(time));
                 var currentShow = attributes.show[0] === 1;
                 if (show !== currentShow) {

Specs/DataSources/StaticGroundPolylinePerMaterialBatchSpec.js

@@ -10,6 +10,7 @@ defineSuite([
         'Core/TimeInterval',
         'Core/TimeIntervalCollection',
         'DataSources/BoundingSphereState',
+        'DataSources/ColorMaterialProperty',
         'DataSources/ConstantProperty',
         'DataSources/Entity',
         'DataSources/PolylineOutlineMaterialProperty',
@@ -32,6 +33,7 @@ defineSuite([
         TimeInterval,
         TimeIntervalCollection,
         BoundingSphereState,
+        ColorMaterialProperty,
         ConstantProperty,
         Entity,
         PolylineOutlineMaterialProperty,
@@ -122,6 +124,52 @@ defineSuite([
         });
     });
 
+    it('updates with sampled color out of range', function() {
+        if (!GroundPolylinePrimitive.isSupported(scene)) {
+            // Don't fail if GroundPolylinePrimitive is not supported
+            return;
+        }
+
+        var validTime = JulianDate.fromIso8601('2018-02-14T04:10:00+1100');
+        var color = new TimeIntervalCollectionProperty();
+        color.intervals.addInterval(TimeInterval.fromIso8601({
+            iso8601: '2018-02-14T04:00:00+1100/2018-02-14T04:15:00+1100',
+            data: Color.RED
+        }));
+        var polyline = createGroundPolyline();
+        polyline.material = new ColorMaterialProperty(color);
+        var entity = new Entity({
+            availability: new TimeIntervalCollection([TimeInterval.fromIso8601({iso8601: '2018-02-14T04:00:00+1100/2018-02-14T04:30:00+1100'})]),
+            polyline: polyline
+        });
+
+        var batch = new StaticGroundPolylinePerMaterialBatch(scene.groundPrimitives);
+
+        var updater = new PolylineGeometryUpdater(entity, scene);
+        batch.add(validTime, updater);
+
+        return pollToPromise(function() {
+            scene.initializeFrame();
+            var isUpdated = batch.update(validTime);
+            scene.render(validTime);
+            return isUpdated;
+        }).then(function() {
+            expect(scene.groundPrimitives.length).toEqual(1);
+            var primitive = scene.groundPrimitives.get(0);
+            var attributes = primitive.getGeometryInstanceAttributes(entity);
+            expect(attributes.color).toEqual([255, 0, 0, 255]);
+
+            batch.update(time);
+            scene.render(time);
+
+            primitive = scene.groundPrimitives.get(0);
+            attributes = primitive.getGeometryInstanceAttributes(entity);
+            expect(attributes.color).toEqual([255, 255, 255, 255]);
+
+            batch.removeAllPrimitives();
+        });
+    });
+
     it('updates with sampled distance display condition out of range', function() {
         if (!GroundPolylinePrimitive.isSupported(scene)) {
             // Don't fail if GroundPolylinePrimitive is not supported