From 93d1d37c15366c4cf73938a5775ffc469b0d8a1e Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Thu, 8 Feb 2018 17:26:17 -0500
Subject: [PATCH 1/3] Fixes #6192

---
 Apps/CesiumViewer/CesiumViewer.js            | 8 ++++++++
 Source/Widgets/Viewer/viewerDragDropMixin.js | 3 ++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/Apps/CesiumViewer/CesiumViewer.js b/Apps/CesiumViewer/CesiumViewer.js
index 73edd88034f6..576dbdcc950c 100644
--- a/Apps/CesiumViewer/CesiumViewer.js
+++ b/Apps/CesiumViewer/CesiumViewer.js
@@ -1,5 +1,6 @@
 define([
         'Cesium/Core/Cartesian3',
+        'Cesium/Core/CesiumTerrainProvider',
         'Cesium/Core/defined',
         'Cesium/Core/formatError',
         'Cesium/Core/Math',
@@ -15,6 +16,7 @@ define([
         'domReady!'
     ], function(
         Cartesian3,
+        CesiumTerrainProvider,
         defined,
         formatError,
         CesiumMath,
@@ -58,6 +60,12 @@ define([
             scene3DOnly : endUserOptions.scene3DOnly,
             requestRenderMode : true
         });
+
+        viewer.terrainProvider = new CesiumTerrainProvider({
+            url : 'https://assets.agi.com/stk-terrain/v1/tilesets/world/tiles',
+            requestWaterMask : true,
+            requestVertexNormals : true
+        });
     } catch (exception) {
         loadingIndicator.style.display = 'none';
         var message = formatError(exception);
diff --git a/Source/Widgets/Viewer/viewerDragDropMixin.js b/Source/Widgets/Viewer/viewerDragDropMixin.js
index e3c6d3f443c2..81f6acf00525 100644
--- a/Source/Widgets/Viewer/viewerDragDropMixin.js
+++ b/Source/Widgets/Viewer/viewerDragDropMixin.js
@@ -272,7 +272,8 @@ define([
                         sourceUri : fileName,
                         proxy : proxy,
                         camera : scene.camera,
-                        canvas : scene.canvas
+                        canvas : scene.canvas,
+                        clampToGround: clampToGround
                     });
                 } else {
                     viewer.dropError.raiseEvent(viewer, fileName, 'Unrecognized file: ' + fileName);

From 5c3e88d54052b3d9b004317e1c12bc3158903508 Mon Sep 17 00:00:00 2001
From: Hannah <pinkos.hannah@gmail.com>
Date: Fri, 9 Feb 2018 18:14:58 -0500
Subject: [PATCH 2/3] Update CHANGES.md

---
 CHANGES.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/CHANGES.md b/CHANGES.md
index 0dcfd8ed5311..350d82317c9d 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -6,6 +6,9 @@ Change Log
 ##### 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)
 
+##### Additions :tada:
+* Enable terrain in the `CesiumViewer` demo application [#6198](https://github.com/AnalyticalGraphicsInc/cesium/pull/6198)
+
 ### 1.42.1 - 2018-02-01
 _This is an npm-only release to fix an issue with using Cesium in Node.js.__
 * Fixed a bug where Cesium would fail to load under Node.js. [#6177](https://github.com/AnalyticalGraphicsInc/cesium/pull/6177)

From 99881167b816f9eb38ec4ea8548bf7bb1c7b7ef1 Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Tue, 13 Feb 2018 11:14:18 -0500
Subject: [PATCH 3/3] cleanup

---
 Apps/CesiumViewer/CesiumViewer.js | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/Apps/CesiumViewer/CesiumViewer.js b/Apps/CesiumViewer/CesiumViewer.js
index 576dbdcc950c..44481f6aa6cb 100644
--- a/Apps/CesiumViewer/CesiumViewer.js
+++ b/Apps/CesiumViewer/CesiumViewer.js
@@ -54,18 +54,24 @@ define([
     var loadingIndicator = document.getElementById('loadingIndicator');
     var viewer;
     try {
+        var hasBaseLayerPicker = !defined(imageryProvider);
         viewer = new Viewer('cesiumContainer', {
             imageryProvider : imageryProvider,
-            baseLayerPicker : !defined(imageryProvider),
+            baseLayerPicker : hasBaseLayerPicker,
             scene3DOnly : endUserOptions.scene3DOnly,
             requestRenderMode : true
         });
 
-        viewer.terrainProvider = new CesiumTerrainProvider({
-            url : 'https://assets.agi.com/stk-terrain/v1/tilesets/world/tiles',
-            requestWaterMask : true,
-            requestVertexNormals : true
-        });
+        if (hasBaseLayerPicker) {
+            var viewModel = viewer.baseLayerPicker.viewModel;
+            viewModel.selectedTerrain = viewModel.terrainProviderViewModels[1];
+        } else {
+            viewer.terrainProvider = new CesiumTerrainProvider({
+                url: 'https://assets.agi.com/stk-terrain/v1/tilesets/world/tiles',
+                requestWaterMask: true,
+                requestVertexNormals: true
+            });
+        }
     } catch (exception) {
         loadingIndicator.style.display = 'none';
         var message = formatError(exception);