Fix billboard entity show/hide

CHANGES.md

@@ -16,6 +16,7 @@ Change Log
 * Added `Rectangle.simpleIntersection`.
 * Added the ability to specify retina options, such as `@2x.png`, via the `MapboxImageryProvider` `format` option.
 * Removed an unnecessary reprojection of Web Mercator imagery tiles to the Geographic projection on load.  This should improve both visual quality and load performance slightly.
+* Fix a issue where a billboard entity would not render after toggling the show propery. [#4408](https://github.com/AnalyticalGraphicsInc/cesium/issues/4408)
 
 ### 1.26 - 2016-10-03
 

Source/DataSources/BillboardVisualizer.js

@@ -148,7 +148,7 @@ define([
             }
 
             billboard.show = show;
-            if (item.textureValue !== textureValue) {
+            if (!defined(billboard.image) || item.textureValue !== textureValue) {
                 billboard.image = textureValue;
                 item.textureValue = textureValue;
             }

Specs/DataSources/BillboardVisualizerSpec.js

@@ -204,6 +204,83 @@ defineSuite([
         });
     });
 
+    it('Display billboard after toggling show', function() {
+        var entityCollection = new EntityCollection();
+        visualizer = new BillboardVisualizer(entityCluster, entityCollection);
+
+        var testObject = entityCollection.getOrCreateEntity('test');
+
+        var time = JulianDate.now();
+        var billboard = testObject.billboard = new BillboardGraphics();
+        var bb;
+
+        testObject.position = new ConstantProperty(new Cartesian3(1234, 5678, 9101112));
+        billboard.show = new ConstantProperty(true);
+        billboard.color = new ConstantProperty(new Color(0.5, 0.5, 0.5, 0.5));
+        billboard.image = new ConstantProperty('Data/Images/Blue.png');
+        billboard.imageSubRegion = new ConstantProperty(new BoundingRectangle(0, 0, 1, 1));
+        billboard.eyeOffset = new ConstantProperty(new Cartesian3(1.0, 2.0, 3.0));
+        billboard.scale = new ConstantProperty(12.5);
+        billboard.rotation = new ConstantProperty(1.5);
+        billboard.alignedAxis = new ConstantProperty(Cartesian3.UNIT_Z);
+        billboard.heightReference = new ConstantProperty(HeightReference.CLAMP_TO_GROUND);
+        billboard.horizontalOrigin = new ConstantProperty(HorizontalOrigin.RIGHT);
+        billboard.verticalOrigin = new ConstantProperty(VerticalOrigin.TOP);
+        billboard.pixelOffset = new ConstantProperty(new Cartesian2(3, 2));
+        billboard.width = new ConstantProperty(15);
+        billboard.height = new ConstantProperty(5);
+        billboard.scaleByDistance = new ConstantProperty(new NearFarScalar());
+        billboard.translucencyByDistance = new ConstantProperty(new NearFarScalar());
+        billboard.pixelOffsetScaleByDistance = new ConstantProperty(new NearFarScalar(1.0, 0.0, 3.0e9, 0.0));
+        billboard.sizeInMeters = new ConstantProperty(true);
+        billboard.distanceDisplayCondition = new ConstantProperty(new DistanceDisplayCondition(10.0, 100.0));
+
+        visualizer.update(time);
+
+        var billboardCollection = entityCluster._billboardCollection;
+        expect(billboardCollection.length).toEqual(1);
+
+        bb = billboardCollection.get(0);
+
+        return pollToPromise(function() {
+            visualizer.update(time);
+            return bb.show; //true once the image is loaded.
+        }).then(function() {
+            billboard.show = new ConstantProperty(false);
+
+            return pollToPromise(function() {
+                visualizer.update(time);
+                return !bb.show;
+            }).then(function() {
+		billboard.show = new ConstantProperty(true);
+
+		return pollToPromise(function() {
+		    visualizer.update(time);
+		    return bb.show;
+		}).then(function() {
+		    expect(bb.position).toEqual(testObject.position.getValue(time));
+		    expect(bb.color).toEqual(testObject.billboard.color.getValue(time));
+		    expect(bb.eyeOffset).toEqual(testObject.billboard.eyeOffset.getValue(time));
+		    expect(bb.scale).toEqual(testObject.billboard.scale.getValue(time));
+		    expect(bb.rotation).toEqual(testObject.billboard.rotation.getValue(time));
+		    expect(bb.alignedAxis).toEqual(testObject.billboard.alignedAxis.getValue(time));
+		    expect(bb.heightReference).toEqual(testObject.billboard.heightReference.getValue(time));
+		    expect(bb.horizontalOrigin).toEqual(testObject.billboard.horizontalOrigin.getValue(time));
+		    expect(bb.verticalOrigin).toEqual(testObject.billboard.verticalOrigin.getValue(time));
+		    expect(bb.width).toEqual(testObject.billboard.width.getValue(time));
+		    expect(bb.height).toEqual(testObject.billboard.height.getValue(time));
+		    expect(bb.scaleByDistance).toEqual(testObject.billboard.scaleByDistance.getValue(time));
+		    expect(bb.translucencyByDistance).toEqual(testObject.billboard.translucencyByDistance.getValue(time));
+		    expect(bb.pixelOffsetScaleByDistance).toEqual(testObject.billboard.pixelOffsetScaleByDistance.getValue(time));
+		    expect(bb.sizeInMeters).toEqual(testObject.billboard.sizeInMeters.getValue(time));
+		    expect(bb.distanceDisplayCondition).toEqual(testObject.billboard.distanceDisplayCondition.getValue(time));
+		    expect(bb.image).toBeDefined();
+		    expect(bb._imageSubRegion).toEqual(testObject.billboard.imageSubRegion.getValue(time));
+		});
+	    });
+        });
+    });
+
     it('Reuses primitives when hiding one and showing another', function() {
         var time = JulianDate.now();
         var entityCollection = new EntityCollection();