New fill tile code kinda working.

Author: kring

Apps/Sandcastle/gallery/TerrainPerformance.html

@@ -36,10 +36,11 @@
 var statistics = Cesium.RequestScheduler.statistics;
 
 // var cesiumTerrainProviderMeshes = new Cesium.CesiumTerrainProvider({
-//     url : 'http://localhost:8081/2018-07-11b',
+//     url : 'http://localhost:8001/2018-07-11b',
 //     requestWaterMask : true,
 //     requestVertexNormals : true
 // });
+// viewer.terrainProvider = cesiumTerrainProviderMeshes;
 viewer.terrainProvider = Cesium.createWorldTerrain();
 
 var startTime;

Source/Scene/GlobeSurfaceTile.js

@@ -181,7 +181,7 @@ define([
     var scratchResult = new Cartesian3();
 
     GlobeSurfaceTile.prototype.pick = function(ray, mode, projection, cullBackFaces, result) {
-        var mesh = this.mesh || this.fill.mesh;
+        var mesh = this.mesh || (this.fill && this.fill.mesh);
         if (!defined(mesh)) {
             return undefined;
         }

Source/Scene/GlobeSurfaceTileProvider.js

@@ -510,7 +510,7 @@ define([
 
         // If this frame has a mix of loaded and fill tiles, we need to propagate
         // loaded heights to the fill tiles.
-        if (this._hasFillTilesThisFrame && this._hasLoadedTilesThisFrame) {
+        if (this.missingTileStrategy === MissingTileStrategy.CREATE_FILL_TILE && this._hasFillTilesThisFrame && this._hasLoadedTilesThisFrame) {
             TerrainFillMesh.updateFillTiles(this, this._quadtree._tilesToRender, frameState);
         }