Merge pull request #3896 from AnalyticalGraphicsInc/terrain-exaggeration

Fix terrain exaggeration bug

CHANGES.md

@@ -22,6 +22,7 @@ Change Log
 * Fixed issue causing the fog to go dark and the atmosphere to flicker when the camera clips the globe. [#3178](https://github.com/AnalyticalGraphicsInc/cesium/issues/3178)
 * Fixed a bug that caused an exception and rendering to stop when using `ArcGisMapServerImageryProvider` to connect to a MapServer specifying the Web Mercator projection and a fullExtent bigger than the valid extent of the projection. [#3854](https://github.com/AnalyticalGraphicsInc/cesium/pull/3854)
 * Fixed issue causing an exception when switching scene modes with an active KML network link. [#3865](https://github.com/AnalyticalGraphicsInc/cesium/issues/3865)
+* Fixed exaggerated terrain tiles disappearing. [#3676](https://github.com/AnalyticalGraphicsInc/cesium/issues/3676)
 
 ### 1.20 - 2016-04-01
 

Source/Core/EllipsoidalOccluder.js

@@ -238,48 +238,6 @@ define([
         return magnitudeToPoint(scaledSpaceDirectionToPoint, resultMagnitude, result);
     };
 
-    /**
-     * Computes a point that can be used for horizon culling from a list of positions.  If the point is below
-     * the horizon, all of the positions are guaranteed to be below the horizon as well.  The returned point
-     * is expressed in the ellipsoid-scaled space and is suitable for use with
-     * {@link EllipsoidalOccluder#isScaledSpacePointVisible}.
-     *
-     * @param {Cartesian3} directionToPoint The direction that the computed point will lie along.
-     *                     A reasonable direction to use is the direction from the center of the ellipsoid to
-     *                     the center of the bounding sphere computed from the positions.  The direction need not
-     *                     be normalized.
-     * @param {Cartesian3[]} points  The vertices from which to compute the horizon culling point.  The positions
-     *                   must be expressed in a reference frame centered at the ellipsoid and aligned with the
-     *                   ellipsoid's axes.
-     * @param {Cartesian3} [result] The instance on which to store the result instead of allocating a new instance.
-     * @returns {Cartesian3} The computed horizon culling point, expressed in the ellipsoid-scaled space.
-     */
-    EllipsoidalOccluder.prototype.computeHorizonCullingPointFromPoints = function(directionToPoint, points, result) {
-        //>>includeStart('debug', pragmas.debug);
-        if (!defined(directionToPoint)) {
-            throw new DeveloperError('directionToPoint is required');
-        }
-        if (!defined(points)) {
-            throw new DeveloperError('points is required');
-        }
-        //>>includeEnd('debug');
-
-        if (!defined(result)) {
-            result = new Cartesian3();
-        }
-
-        var ellipsoid = this._ellipsoid;
-        var scaledSpaceDirectionToPoint = computeScaledSpaceDirectionToPoint(ellipsoid, directionToPoint);
-        var resultMagnitude = 0.0;
-
-        for (var i = 0, len = points.length; i < len; ++i) {
-            var candidateMagnitude = computeMagnitude(ellipsoid, points[i], scaledSpaceDirectionToPoint);
-            resultMagnitude = Math.max(resultMagnitude, candidateMagnitude);
-        }
-
-        return magnitudeToPoint(scaledSpaceDirectionToPoint, resultMagnitude, result);
-    };
-
     var subsampleScratch = [];
 
     /**

Source/Core/HeightmapTessellator.js

@@ -365,7 +365,7 @@ define([
         var center = options.relativetoCenter;
         if (defined(center)) {
             var occluder = new EllipsoidalOccluder(ellipsoid);
-            occludeePointInScaledSpace = occluder.computeHorizonCullingPointFromPoints(center, positions);
+            occludeePointInScaledSpace = occluder.computeHorizonCullingPoint(center, positions);
         }
 
         var aaBox = new AxisAlignedBoundingBox(minimum, maximum, relativeToCenter);

Source/Core/QuantizedMeshTerrainData.js

@@ -305,7 +305,7 @@ define([
             var maximumHeight = result.maximumHeight;
             var boundingSphere = defaultValue(result.boundingSphere, that._boundingSphere);
             var obb = defaultValue(result.orientedBoundingBox, that._orientedBoundingBox);
-            var occlusionPoint = defaultValue(result.occludeePointInScaledSpace, that._horizonOcclusionPoint);
+            var occlusionPoint = that._horizonOcclusionPoint;
             var stride = result.vertexStride;
             var terrainEncoding = TerrainEncoding.clone(result.encoding);
 

Source/Workers/createVerticesFromQuantizedTerrainMesh.js

@@ -8,7 +8,6 @@ define([
         '../Core/Cartographic',
         '../Core/defined',
         '../Core/Ellipsoid',
-        '../Core/EllipsoidalOccluder',
         '../Core/IndexDatatype',
         '../Core/Math',
         '../Core/Matrix3',
@@ -26,7 +25,6 @@ define([
         Cartographic,
         defined,
         Ellipsoid,
-        EllipsoidalOccluder,
         IndexDatatype,
         CesiumMath,
         Matrix3,
@@ -111,17 +109,13 @@ define([
             Cartesian3.maximumByComponent(cartesian3Scratch, maximum, maximum);
         }
 
-        var occludeePointInScaledSpace;
         var orientedBoundingBox;
         var boundingSphere;
 
         if (exaggeration !== 1.0) {
             // Bounding volumes and horizon culling point need to be recomputed since the tile payload assumes no exaggeration.
             boundingSphere = BoundingSphere.fromPoints(positions);
             orientedBoundingBox = OrientedBoundingBox.fromRectangle(rectangle, minimumHeight, maximumHeight, ellipsoid);
-
-            var occluder = new EllipsoidalOccluder(ellipsoid);
-            occludeePointInScaledSpace = occluder.computeHorizonCullingPointFromPoints(center, positions);
         }
 
         var hMin = minimumHeight;
@@ -189,7 +183,6 @@ define([
             maximumHeight : maximumHeight,
             boundingSphere : boundingSphere,
             orientedBoundingBox : orientedBoundingBox,
-            occludeePointInScaledSpace : occludeePointInScaledSpace,
             encoding : encoding,
             skirtIndex : parameters.indices.length
         };

Specs/Core/EllipsoidalOccluderSpec.js

@@ -255,41 +255,6 @@ defineSuite([
         });
     });
 
-    describe('computeHorizonCullingPointFromPoints', function() {
-        it('requires directionToPointand points', function() {
-            var ellipsoid = new Ellipsoid(12345.0, 12345.0, 12345.0);
-            var ellipsoidalOccluder = new EllipsoidalOccluder(ellipsoid);
-
-            var positions = [new Cartesian3(-12345.0, 12345.0, 12345.0), new Cartesian3(-12346.0, 12345.0, 12345.0), new Cartesian3(-12446.0, 12445.0, 12445.0)];
-            var boundingSphere = BoundingSphere.fromPoints(positions);
-
-            ellipsoidalOccluder.computeHorizonCullingPointFromPoints(boundingSphere.center, positions);
-
-            expect(function() {
-                ellipsoidalOccluder.computeHorizonCullingPointFromPoints(undefined, positions);
-            }).toThrowDeveloperError();
-
-            expect(function() {
-                ellipsoidalOccluder.computeHorizonCullingPointFromPoints(boundingSphere.center, undefined);
-            }).toThrowDeveloperError();
-        });
-
-        it('produces same answers as computeHorizonCullingPoint', function() {
-            var ellipsoid = new Ellipsoid(12345.0, 12345.0, 12345.0);
-            var ellipsoidalOccluder = new EllipsoidalOccluder(ellipsoid);
-
-            var positions = [new Cartesian3(-12345.0, 12345.0, 12345.0), new Cartesian3(-12346.0, 12345.0, 12345.0), new Cartesian3(-12446.0, 12445.0, 12445.0)];
-            var boundingSphere = BoundingSphere.fromPoints(positions);
-
-            var result1 = ellipsoidalOccluder.computeHorizonCullingPoint(boundingSphere.center, positions);
-            var result2 = ellipsoidalOccluder.computeHorizonCullingPointFromPoints(boundingSphere.center, positions);
-
-            expect(result1.x).toEqualEpsilon(result2.x, CesiumMath.EPSILON14);
-            expect(result1.y).toEqualEpsilon(result2.y, CesiumMath.EPSILON14);
-            expect(result1.z).toEqualEpsilon(result2.z, CesiumMath.EPSILON14);
-        });
-    });
-
     describe('computeHorizonCullingPointFromRectangle', function() {
         it('returns undefined for global rectangle', function() {
             var ellipsoid = new Ellipsoid(12345.0, 12345.0, 12345.0);