Do not use rubbish OBB for single root tile

CHANGES.md

@@ -28,6 +28,7 @@ Change Log
 * Fixed an error where `clampToHeightMostDetailed` or `sampleHeightMostDetailed` would crash if entities were created when the promise resolved. [#7690](https://github.com/AnalyticalGraphicsInc/cesium/pull/7690)
 * Fixed an issue with compositing merged entity availability. [#7717](https://github.com/AnalyticalGraphicsInc/cesium/issues/7717)
 * Fixed an error where many imagery layers within a single tile would cause parts of the tile to render as black on some platforms. [#7649](https://github.com/AnalyticalGraphicsInc/cesium/issues/7649)
+* Fixed a bug that could cause terrain with a single, global root tile (e.g. that uses `WebMercatorTilingScheme`) to be culled unexpectedly in some views. [#7702](https://github.com/AnalyticalGraphicsInc/cesium/issues/7702)
 * Fixed a problem where instanced 3D models were incorrectly lit when using physically based materials. [#7775](https://github.com/AnalyticalGraphicsInc/cesium/issues/7775)
 
 ### 1.56.1 - 2019-04-02

Source/Core/GoogleEarthEnterpriseTerrainData.js

@@ -193,16 +193,18 @@ define([
         var that = this;
         return verticesPromise
             .then(function(result) {
+                // Clone complex result objects because the transfer from the web worker
+                // has stripped them down to JSON-style objects.
                 that._mesh = new TerrainMesh(
                     center,
                     new Float32Array(result.vertices),
                     new Uint16Array(result.indices),
                     result.minimumHeight,
                     result.maximumHeight,
-                    result.boundingSphere3D,
-                    result.occludeePointInScaledSpace,
+                    BoundingSphere.clone(result.boundingSphere3D),
+                    Cartesian3.clone(result.occludeePointInScaledSpace),
                     result.numberOfAttributes,
-                    result.orientedBoundingBox,
+                    OrientedBoundingBox.clone(result.orientedBoundingBox),
                     TerrainEncoding.clone(result.encoding),
                     exaggeration,
                     result.westIndicesSouthToNorth,

Source/Core/HeightmapTerrainData.js

@@ -1,11 +1,14 @@
 define([
         '../ThirdParty/when',
+        './BoundingSphere',
+        './Cartesian3',
         './defaultValue',
         './defined',
         './defineProperties',
         './DeveloperError',
         './GeographicProjection',
         './HeightmapTessellator',
+        './OrientedBoundingBox',
         './Math',
         './Rectangle',
         './TaskProcessor',
@@ -14,12 +17,15 @@ define([
         './TerrainProvider'
     ], function(
         when,
+        BoundingSphere,
+        Cartesian3,
         defaultValue,
         defined,
         defineProperties,
         DeveloperError,
         GeographicProjection,
         HeightmapTessellator,
+        OrientedBoundingBox,
         CesiumMath,
         Rectangle,
         TaskProcessor,
@@ -242,16 +248,18 @@ define([
 
         var that = this;
         return when(verticesPromise, function(result) {
+            // Clone complex result objects because the transfer from the web worker
+            // has stripped them down to JSON-style objects.
             that._mesh = new TerrainMesh(
                     center,
                     new Float32Array(result.vertices),
                     TerrainProvider.getRegularGridIndices(result.gridWidth, result.gridHeight),
                     result.minimumHeight,
                     result.maximumHeight,
-                    result.boundingSphere3D,
-                    result.occludeePointInScaledSpace,
+                    BoundingSphere.clone(result.boundingSphere3D),
+                    Cartesian3.clone(result.occludeePointInScaledSpace),
                     result.numberOfAttributes,
-                    result.orientedBoundingBox,
+                    OrientedBoundingBox.clone(result.orientedBoundingBox),
                     TerrainEncoding.clone(result.encoding),
                     exaggeration,
                     result.westIndicesSouthToNorth,
@@ -324,6 +332,8 @@ define([
             arrayHeight += 2;
         }
 
+        // No need to clone here (as we do in the async version) because the result
+        // is not coming from a web worker.
         return new TerrainMesh(
             center,
             result.vertices,
@@ -334,7 +344,7 @@ define([
             result.occludeePointInScaledSpace,
             result.encoding.getStride(),
             result.orientedBoundingBox,
-            TerrainEncoding.clone(result.encoding),
+            result.encoding,
             exaggeration,
             result.westIndicesSouthToNorth,
             result.southIndicesEastToWest,

Source/Core/QuantizedMeshTerrainData.js

@@ -326,15 +326,17 @@ define([
             var rtc = result.center;
             var minimumHeight = result.minimumHeight;
             var maximumHeight = result.maximumHeight;
-            var boundingSphere = defaultValue(result.boundingSphere, that._boundingSphere);
-            var obb = defaultValue(result.orientedBoundingBox, that._orientedBoundingBox);
-            var occlusionPoint = that._horizonOcclusionPoint;
+            var boundingSphere = defaultValue(BoundingSphere.clone(result.boundingSphere), that._boundingSphere);
+            var obb = defaultValue(OrientedBoundingBox.clone(result.orientedBoundingBox), that._orientedBoundingBox);
+            var occlusionPoint = Cartesian3.clone(that._horizonOcclusionPoint);
             var stride = result.vertexStride;
             var terrainEncoding = TerrainEncoding.clone(result.encoding);
 
             that._skirtIndex = result.skirtIndex;
             that._vertexCountWithoutSkirts = that._quantizedVertices.length / 3;
 
+            // Clone complex result objects because the transfer from the web worker
+            // has stripped them down to JSON-style objects.
             that._mesh = new TerrainMesh(
                     rtc,
                     vertices,

Source/Scene/GlobeSurfaceTile.js

@@ -6,6 +6,7 @@ define([
         '../Core/defineProperties',
         '../Core/IndexDatatype',
         '../Core/IntersectionTests',
+        '../Core/OrientedBoundingBox',
         '../Core/PixelFormat',
         '../Core/Request',
         '../Core/RequestState',
@@ -34,6 +35,7 @@ define([
         defineProperties,
         IndexDatatype,
         IntersectionTests,
+        OrientedBoundingBox,
         PixelFormat,
         Request,
         RequestState,
@@ -511,6 +513,8 @@ define([
 
         when(meshPromise, function(mesh) {
             surfaceTile.mesh = mesh;
+            surfaceTile.orientedBoundingBox = OrientedBoundingBox.clone(mesh.orientedBoundingBox, surfaceTile.orientedBoundingBox);
+            surfaceTile.occludeePointInScaledSpace = Cartesian3.clone(mesh.occludeePointInScaledSpace, surfaceTile.occludeePointInScaledSpace);
             surfaceTile.terrainState = TerrainState.TRANSFORMED;
         }, function() {
             surfaceTile.terrainState = TerrainState.FAILED;

Source/Scene/GlobeSurfaceTileProvider.js

@@ -605,6 +605,10 @@ define([
         var cullingVolume = frameState.cullingVolume;
         var boundingVolume = surfaceTile.orientedBoundingBox;
 
+        if (!defined(boundingVolume) && defined(surfaceTile.renderedMesh)) {
+            boundingVolume = surfaceTile.renderedMesh.boundingSphere3D;
+        }
+
         // Check if the tile is outside the limit area in cartographic space
         surfaceTile.clippedByBoundaries = false;
         var clippedCartographicLimitRectangle = clipRectangleAntimeridian(tile.rectangle, this.cartographicLimitRectangle);
@@ -635,9 +639,14 @@ define([
             }
         }
 
-        var intersection = cullingVolume.computeVisibility(boundingVolume);
-        if (intersection === Intersect.OUTSIDE) {
-            return Visibility.NONE;
+        var intersection = Intersect.INTERSECTING;
+        if (defined(boundingVolume)) {
+            intersection = cullingVolume.computeVisibility(boundingVolume);
+            if (intersection === Intersect.OUTSIDE) {
+                return Visibility.NONE;
+            }
+        } else {
+            console.log('no bounding volume');
         }
 
         var ortho3D = frameState.mode === SceneMode.SCENE3D && frameState.camera.frustum instanceof OrthographicFrustum;
@@ -898,14 +907,18 @@ define([
         } else if (surfaceTile.boundingVolumeSourceTile !== heightSource) {
             // Heights are from a new source tile, so update the bounding volume.
             surfaceTile.boundingVolumeSourceTile = heightSource;
-            surfaceTile.orientedBoundingBox = OrientedBoundingBox.fromRectangle(
-                tile.rectangle,
-                tileBoundingRegion.minimumHeight,
-                tileBoundingRegion.maximumHeight,
-                tile.tilingScheme.ellipsoid,
-                surfaceTile.orientedBoundingBox);
-
-            surfaceTile.occludeePointInScaledSpace = computeOccludeePoint(this, surfaceTile.orientedBoundingBox.center, tile.rectangle, tileBoundingRegion.maximumHeight, surfaceTile.occludeePointInScaledSpace);
+
+            var rectangle = tile.rectangle;
+            if (defined(rectangle) && rectangle.width < CesiumMath.PI_OVER_TWO + CesiumMath.EPSILON5) {
+                surfaceTile.orientedBoundingBox = OrientedBoundingBox.fromRectangle(
+                    tile.rectangle,
+                    tileBoundingRegion.minimumHeight,
+                    tileBoundingRegion.maximumHeight,
+                    tile.tilingScheme.ellipsoid,
+                    surfaceTile.orientedBoundingBox);
+
+                surfaceTile.occludeePointInScaledSpace = computeOccludeePoint(this, surfaceTile.orientedBoundingBox.center, tile.rectangle, tileBoundingRegion.maximumHeight, surfaceTile.occludeePointInScaledSpace);
+            }
         }
 
         var min = tileBoundingRegion.minimumHeight;