RequestRender when loadQueue is not empty

Author: ggetz

CHANGES.md

@@ -20,6 +20,7 @@ Change Log
   * Added `preserveQueryParameters` parameter to `getDerivedResource`, to allow us to append query parameters instead of always replacing them.
   * Added `setQueryParameters` and `appendQueryParameters` to allow for better handling of query strings.
 * Enable terrain in the `CesiumViewer` demo application [#6198](https://github.com/AnalyticalGraphicsInc/cesium/pull/6198)
+* Added `Globe.tilesLoaded` getter property to determine if all terrain and imagery is loaded. [#6194](https://github.com/AnalyticalGraphicsInc/cesium/pull/6194)
 
 ##### Fixes :wrench:
 * Fixed bug where AxisAlignedBoundingBox did not copy over center value when cloning an undefined result. [#6183](https://github.com/AnalyticalGraphicsInc/cesium/pull/6183)

Source/Scene/Globe.js

@@ -326,7 +326,18 @@ define([
                 return this._surface.tileLoadProgressEvent;
             }
         },
-
+        /**
+         * Returns <code>true</code> when the tile load queue is empty, <code>false</code> otherwise.  When the load queue is empty,
+         * all terrain and imagery for the current view have been loaded.
+         * @memeberof Globe.prototype
+         * @type {Boolean}
+         * @readonly
+         */
+        tilesLoaded: {
+            get: function() {
+                return (this._surface._lastTileLoadQueueLength === 0);
+            }
+        },
         /**
          * Gets or sets the material appearance of the Globe.  This can be one of several built-in {@link Material} objects or a custom material, scripted with
          * {@link https://github.com/AnalyticalGraphicsInc/cesium/wiki/Fabric|Fabric}.

Source/Scene/Scene.js

@@ -782,7 +782,6 @@ define([
 
         var removeGlobeCallbacks = [];
         if (defined(globe)) {
-            removeGlobeCallbacks.push(globe.tileLoadedEvent.addEventListener(requestRenderAfterFrame(scene)));
             removeGlobeCallbacks.push(globe.imageryLayersUpdatedEvent.addEventListener(requestRenderAfterFrame(scene)));
             removeGlobeCallbacks.push(globe.terrainProviderChanged.addEventListener(requestRenderAfterFrame(scene)));
         }
@@ -2750,8 +2749,13 @@ define([
         updateDebugFrustumPlanes(scene);
         updateShadowMaps(scene);
 
-        if (scene._globe) {
-            scene._globe.render(frameState);
+        var globe = scene._globe;
+        if (defined(globe)) {
+            globe.render(frameState);
+
+            if (!globe.tilesLoaded) {
+                scene._renderRequested = true;
+            }
         }
     }
 

Specs/createGlobe.js

@@ -26,6 +26,7 @@ define([
             },
             _surface : {},
             tileLoadedEvent : new Event(),
+            tilesLoaded : true,
             imageryLayersUpdatedEvent : new Event(),
             terrainProviderChanged : new Event(),
             destroy : function() {}