cesiumDemo/Source/Workers/createGroundPolylineGeometry.js

/* This file is automatically rebuilt by the Cesium build process. */
define(['./defined-26bd4a03', './Check-da037458', './freezeObject-2d83f591', './defaultValue-f2e68450', './Math-fa6e45cb', './Cartesian2-2a723276', './defineProperties-6f7a50f2', './Transforms-65aba0a4', './RuntimeError-ad75c885', './WebGLConstants-497deb20', './ComponentDatatype-69643096', './GeometryAttribute-ed359d71', './when-ee12a2cb', './EncodedCartesian3-8b2b90d0', './IntersectionTests-c2360ffa', './Plane-a1a3fd52', './WebMercatorProjection-f2dc467d', './arrayRemoveDuplicates-dd708d81', './ArcType-d521909b', './EllipsoidRhumbLine-c6cdbfd3', './EllipsoidGeodesic-53e988a6'], function (defined, Check, freezeObject, defaultValue, _Math, Cartesian2, defineProperties, Transforms, RuntimeError, WebGLConstants, ComponentDatatype, GeometryAttribute, when, EncodedCartesian3, IntersectionTests, Plane, WebMercatorProjection, arrayRemoveDuplicates, ArcType, EllipsoidRhumbLine, EllipsoidGeodesic) { 'use strict';

    /**
         * A tiling scheme for geometry referenced to a simple {@link GeographicProjection} where
         * longitude and latitude are directly mapped to X and Y.  This projection is commonly
         * known as geographic, equirectangular, equidistant cylindrical, or plate carrée.
         *
         * @alias GeographicTilingScheme
         * @constructor
         *
         * @param {Object} [options] Object with the following properties:
         * @param {Ellipsoid} [options.ellipsoid=Ellipsoid.WGS84] The ellipsoid whose surface is being tiled. Defaults to
         * the WGS84 ellipsoid.
         * @param {Rectangle} [options.rectangle=Rectangle.MAX_VALUE] The rectangle, in radians, covered by the tiling scheme.
         * @param {Number} [options.numberOfLevelZeroTilesX=2] The number of tiles in the X direction at level zero of
         * the tile tree.
         * @param {Number} [options.numberOfLevelZeroTilesY=1] The number of tiles in the Y direction at level zero of
         * the tile tree.
         */
        function GeographicTilingScheme(options) {
            options = defaultValue.defaultValue(options, defaultValue.defaultValue.EMPTY_OBJECT);

            this._ellipsoid = defaultValue.defaultValue(options.ellipsoid, Cartesian2.Ellipsoid.WGS84);
            this._rectangle = defaultValue.defaultValue(options.rectangle, Cartesian2.Rectangle.MAX_VALUE);
            this._projection = new Transforms.GeographicProjection(this._ellipsoid);
            this._numberOfLevelZeroTilesX = defaultValue.defaultValue(options.numberOfLevelZeroTilesX, 2);
            this._numberOfLevelZeroTilesY = defaultValue.defaultValue(options.numberOfLevelZeroTilesY, 1);
        }

        defineProperties.defineProperties(GeographicTilingScheme.prototype, {
            /**
             * Gets the ellipsoid that is tiled by this tiling scheme.
             * @memberof GeographicTilingScheme.prototype
             * @type {Ellipsoid}
             */
            ellipsoid : {
                get : function() {
                    return this._ellipsoid;
                }
            },

            /**
             * Gets the rectangle, in radians, covered by this tiling scheme.
             * @memberof GeographicTilingScheme.prototype
             * @type {Rectangle}
             */
            rectangle : {
                get : function() {
                    return this._rectangle;
                }
            },

            /**
             * Gets the map projection used by this tiling scheme.
             * @memberof GeographicTilingScheme.prototype
             * @type {MapProjection}
             */
            projection : {
                get : function() {
                    return this._projection;
                }
            }
        });

        /**
         * Gets the total number of tiles in the X direction at a specified level-of-detail.
         *
         * @param {Number} level The level-of-detail.
         * @returns {Number} The number of tiles in the X direction at the given level.
         */
        GeographicTilingScheme.prototype.getNumberOfXTilesAtLevel = function(level) {
            return this._numberOfLevelZeroTilesX << level;
        };

        /**
         * Gets the total number of tiles in the Y direction at a specified level-of-detail.
         *
         * @param {Number} level The level-of-detail.
         * @returns {Number} The number of tiles in the Y direction at the given level.
         */
        GeographicTilingScheme.prototype.getNumberOfYTilesAtLevel = function(level) {
            return this._numberOfLevelZeroTilesY << level;
        };

        /**
         * Transforms a rectangle specified in geodetic radians to the native coordinate system
         * of this tiling scheme.
         *
         * @param {Rectangle} rectangle The rectangle to transform.
         * @param {Rectangle} [result] The instance to which to copy the result, or undefined if a new instance
         *        should be created.
         * @returns {Rectangle} The specified 'result', or a new object containing the native rectangle if 'result'
         *          is undefined.
         */
        GeographicTilingScheme.prototype.rectangleToNativeRectangle = function(rectangle, result) {
            //>>includeStart('debug', pragmas.debug);
            Check.Check.defined('rectangle', rectangle);
            //>>includeEnd('debug');

            var west = _Math.CesiumMath.toDegrees(rectangle.west);
            var south = _Math.CesiumMath.toDegrees(rectangle.south);
            var east = _Math.CesiumMath.toDegrees(rectangle.east);
            var north = _Math.CesiumMath.toDegrees(rectangle.north);

            if (!defined.defined(result)) {
                return new Cartesian2.Rectangle(west, south, east, north);
            }

            result.west = west;
            result.south = south;
            result.east = east;
            result.north = north;
            return result;
        };

        /**
         * Converts tile x, y coordinates and level to a rectangle expressed in the native coordinates
         * of the tiling scheme.
         *
         * @param {Number} x The integer x coordinate of the tile.
         * @param {Number} y The integer y coordinate of the tile.
         * @param {Number} level The tile level-of-detail.  Zero is the least detailed.
         * @param {Object} [result] The instance to which to copy the result, or undefined if a new instance
         *        should be created.
         * @returns {Rectangle} The specified 'result', or a new object containing the rectangle
         *          if 'result' is undefined.
         */
        GeographicTilingScheme.prototype.tileXYToNativeRectangle = function(x, y, level, result) {
            var rectangleRadians = this.tileXYToRectangle(x, y, level, result);
            rectangleRadians.west = _Math.CesiumMath.toDegrees(rectangleRadians.west);
            rectangleRadians.south = _Math.CesiumMath.toDegrees(rectangleRadians.south);
            rectangleRadians.east = _Math.CesiumMath.toDegrees(rectangleRadians.east);
            rectangleRadians.north = _Math.CesiumMath.toDegrees(rectangleRadians.north);
            return rectangleRadians;
        };

        /**
         * Converts tile x, y coordinates and level to a cartographic rectangle in radians.
         *
         * @param {Number} x The integer x coordinate of the tile.
         * @param {Number} y The integer y coordinate of the tile.
         * @param {Number} level The tile level-of-detail.  Zero is the least detailed.
         * @param {Object} [result] The instance to which to copy the result, or undefined if a new instance
         *        should be created.
         * @returns {Rectangle} The specified 'result', or a new object containing the rectangle
         *          if 'result' is undefined.
         */
        GeographicTilingScheme.prototype.tileXYToRectangle = function(x, y, level, result) {
            var rectangle = this._rectangle;

            var xTiles = this.getNumberOfXTilesAtLevel(level);
            var yTiles = this.getNumberOfYTilesAtLevel(level);

            var xTileWidth = rectangle.width / xTiles;
            var west = x * xTileWidth + rectangle.west;
            var east = (x + 1) * xTileWidth + rectangle.west;

            var yTileHeight = rectangle.height / yTiles;
            var north = rectangle.north - y * yTileHeight;
            var south = rectangle.north - (y + 1) * yTileHeight;

            if (!defined.defined(result)) {
                result = new Cartesian2.Rectangle(west, south, east, north);
            }

            result.west = west;
            result.south = south;
            result.east = east;
            result.north = north;
            return result;
        };

        /**
         * Calculates the tile x, y coordinates of the tile containing
         * a given cartographic position.
         *
         * @param {Cartographic} position The position.
         * @param {Number} level The tile level-of-detail.  Zero is the least detailed.
         * @param {Cartesian2} [result] The instance to which to copy the result, or undefined if a new instance
         *        should be created.
         * @returns {Cartesian2} The specified 'result', or a new object containing the tile x, y coordinates
         *          if 'result' is undefined.
         */
        GeographicTilingScheme.prototype.positionToTileXY = function(position, level, result) {
            var rectangle = this._rectangle;
            if (!Cartesian2.Rectangle.contains(rectangle, position)) {
                // outside the bounds of the tiling scheme
                return undefined;
            }

            var xTiles = this.getNumberOfXTilesAtLevel(level);
            var yTiles = this.getNumberOfYTilesAtLevel(level);

            var xTileWidth = rectangle.width / xTiles;
            var yTileHeight = rectangle.height / yTiles;

            var longitude = position.longitude;
            if (rectangle.east < rectangle.west) {
                longitude += _Math.CesiumMath.TWO_PI;
            }

            var xTileCoordinate = (longitude - rectangle.west) / xTileWidth | 0;
            if (xTileCoordinate >= xTiles) {
                xTileCoordinate = xTiles - 1;
            }

            var yTileCoordinate = (rectangle.north - position.latitude) / yTileHeight | 0;
            if (yTileCoordinate >= yTiles) {
                yTileCoordinate = yTiles - 1;
            }

            if (!defined.defined(result)) {
                return new Cartesian2.Cartesian2(xTileCoordinate, yTileCoordinate);
            }

            result.x = xTileCoordinate;
            result.y = yTileCoordinate;
            return result;
        };

    var scratchDiagonalCartesianNE = new Cartesian2.Cartesian3();
        var scratchDiagonalCartesianSW = new Cartesian2.Cartesian3();
        var scratchDiagonalCartographic = new Cartesian2.Cartographic();
        var scratchCenterCartesian = new Cartesian2.Cartesian3();
        var scratchSurfaceCartesian = new Cartesian2.Cartesian3();

        var scratchBoundingSphere = new Transforms.BoundingSphere();
        var tilingScheme = new GeographicTilingScheme();
        var scratchCorners = [new Cartesian2.Cartographic(), new Cartesian2.Cartographic(), new Cartesian2.Cartographic(), new Cartesian2.Cartographic()];
        var scratchTileXY = new Cartesian2.Cartesian2();

        /**
         * A collection of functions for approximating terrain height
         * @private
         */
        var ApproximateTerrainHeights = {};

        /**
         * Initializes the minimum and maximum terrain heights
         * @return {Promise}
         */
        ApproximateTerrainHeights.initialize = function() {
            var initPromise = ApproximateTerrainHeights._initPromise;
            if (defined.defined(initPromise)) {
                return initPromise;
            }

            initPromise = Transforms.Resource.fetchJson(Transforms.buildModuleUrl('Assets/approximateTerrainHeights.json'))
                .then(function(json) {
                    ApproximateTerrainHeights._terrainHeights = json;
                });
            ApproximateTerrainHeights._initPromise = initPromise;

            return initPromise;
        };

        /**
         * Computes the minimum and maximum terrain heights for a given rectangle
         * @param {Rectangle} rectangle The bounding rectangle
         * @param {Ellipsoid} [ellipsoid=Ellipsoid.WGS84] The ellipsoid
         * @return {{minimumTerrainHeight: Number, maximumTerrainHeight: Number}}
         */
        ApproximateTerrainHeights.getMinimumMaximumHeights = function(rectangle, ellipsoid) {
            //>>includeStart('debug', pragmas.debug);
            Check.Check.defined('rectangle', rectangle);
            if (!defined.defined(ApproximateTerrainHeights._terrainHeights)) {
                throw new Check.DeveloperError('You must call ApproximateTerrainHeights.initialize and wait for the promise to resolve before using this function');
            }
            //>>includeEnd('debug');
            ellipsoid = defaultValue.defaultValue(ellipsoid, Cartesian2.Ellipsoid.WGS84);

            var xyLevel = getTileXYLevel(rectangle);

            // Get the terrain min/max for that tile
            var minTerrainHeight = ApproximateTerrainHeights._defaultMinTerrainHeight;
            var maxTerrainHeight = ApproximateTerrainHeights._defaultMaxTerrainHeight;
            if (defined.defined(xyLevel)) {
                var key = xyLevel.level + '-' + xyLevel.x + '-' + xyLevel.y;
                var heights = ApproximateTerrainHeights._terrainHeights[key];
                if (defined.defined(heights)) {
                    minTerrainHeight = heights[0];
                    maxTerrainHeight = heights[1];
                }

                // Compute min by taking the center of the NE->SW diagonal and finding distance to the surface
                ellipsoid.cartographicToCartesian(Cartesian2.Rectangle.northeast(rectangle, scratchDiagonalCartographic),
                    scratchDiagonalCartesianNE);
                ellipsoid.cartographicToCartesian(Cartesian2.Rectangle.southwest(rectangle, scratchDiagonalCartographic),
                    scratchDiagonalCartesianSW);

                Cartesian2.Cartesian3.midpoint(scratchDiagonalCartesianSW, scratchDiagonalCartesianNE, scratchCenterCartesian);
                var surfacePosition = ellipsoid.scaleToGeodeticSurface(scratchCenterCartesian, scratchSurfaceCartesian);
                if (defined.defined(surfacePosition)) {
                    var distance = Cartesian2.Cartesian3.distance(scratchCenterCartesian, surfacePosition);
                    minTerrainHeight = Math.min(minTerrainHeight, -distance);
                } else {
                    minTerrainHeight = ApproximateTerrainHeights._defaultMinTerrainHeight;
                }
            }

            minTerrainHeight = Math.max(ApproximateTerrainHeights._defaultMinTerrainHeight, minTerrainHeight);

            return {
                minimumTerrainHeight: minTerrainHeight,
                maximumTerrainHeight: maxTerrainHeight
            };
        };

        /**
         * Computes the bounding sphere based on the tile heights in the rectangle
         * @param {Rectangle} rectangle The bounding rectangle
         * @param {Ellipsoid} [ellipsoid=Ellipsoid.WGS84] The ellipsoid
         * @return {BoundingSphere} The result bounding sphere
         */
        ApproximateTerrainHeights.getBoundingSphere = function(rectangle, ellipsoid) {
            //>>includeStart('debug', pragmas.debug);
            Check.Check.defined('rectangle', rectangle);
            if (!defined.defined(ApproximateTerrainHeights._terrainHeights)) {
                throw new Check.DeveloperError('You must call ApproximateTerrainHeights.initialize and wait for the promise to resolve before using this function');
            }
            //>>includeEnd('debug');
            ellipsoid = defaultValue.defaultValue(ellipsoid, Cartesian2.Ellipsoid.WGS84);

            var xyLevel = getTileXYLevel(rectangle);

            // Get the terrain max for that tile
            var maxTerrainHeight = ApproximateTerrainHeights._defaultMaxTerrainHeight;
            if (defined.defined(xyLevel)) {
                var key = xyLevel.level + '-' + xyLevel.x + '-' + xyLevel.y;
                var heights = ApproximateTerrainHeights._terrainHeights[key];
                if (defined.defined(heights)) {
                    maxTerrainHeight = heights[1];
                }
            }

            var result = Transforms.BoundingSphere.fromRectangle3D(rectangle, ellipsoid, 0.0);
            Transforms.BoundingSphere.fromRectangle3D(rectangle, ellipsoid, maxTerrainHeight, scratchBoundingSphere);

            return Transforms.BoundingSphere.union(result, scratchBoundingSphere, result);
        };

        function getTileXYLevel(rectangle) {
            Cartesian2.Cartographic.fromRadians(rectangle.east, rectangle.north, 0.0, scratchCorners[0]);
            Cartesian2.Cartographic.fromRadians(rectangle.west, rectangle.north, 0.0, scratchCorners[1]);
            Cartesian2.Cartographic.fromRadians(rectangle.east, rectangle.south, 0.0, scratchCorners[2]);
            Cartesian2.Cartographic.fromRadians(rectangle.west, rectangle.south, 0.0, scratchCorners[3]);

            // Determine which tile the bounding rectangle is in
            var lastLevelX = 0, lastLevelY = 0;
            var currentX = 0, currentY = 0;
            var maxLevel = ApproximateTerrainHeights._terrainHeightsMaxLevel;
            var i;
            for(i = 0; i <= maxLevel; ++i) {
                var failed = false;
                for(var j = 0; j < 4; ++j) {
                    var corner = scratchCorners[j];
                    tilingScheme.positionToTileXY(corner, i, scratchTileXY);
                    if (j === 0) {
                        currentX = scratchTileXY.x;
                        currentY = scratchTileXY.y;
                    } else if(currentX !== scratchTileXY.x || currentY !== scratchTileXY.y) {
                        failed = true;
                        break;
                    }
                }

                if (failed) {
                    break;
                }

                lastLevelX = currentX;
                lastLevelY = currentY;
            }

            if (i === 0) {
                return undefined;
            }

            return {
                x : lastLevelX,
                y : lastLevelY,
                level : (i > maxLevel) ? maxLevel : (i - 1)
            };
        }

        ApproximateTerrainHeights._terrainHeightsMaxLevel = 6;
        ApproximateTerrainHeights._defaultMaxTerrainHeight = 9000.0;
        ApproximateTerrainHeights._defaultMinTerrainHeight = -100000.0;
        ApproximateTerrainHeights._terrainHeights = undefined;
        ApproximateTerrainHeights._initPromise = undefined;

        defineProperties.defineProperties(ApproximateTerrainHeights, {
            /**
             * Determines if the terrain heights are initialized and ready to use. To initialize the terrain heights,
             * call {@link ApproximateTerrainHeights#initialize} and wait for the returned promise to resolve.
             * @type {Boolean}
             * @readonly
             * @memberof ApproximateTerrainHeights
             */
            initialized: {
                get: function() {
                    return defined.defined(ApproximateTerrainHeights._terrainHeights);
                }
            }
        });

    var PROJECTIONS = [Transforms.GeographicProjection, WebMercatorProjection.WebMercatorProjection];
        var PROJECTION_COUNT = PROJECTIONS.length;

        var MITER_BREAK_SMALL = Math.cos(_Math.CesiumMath.toRadians(30.0));
        var MITER_BREAK_LARGE = Math.cos(_Math.CesiumMath.toRadians(150.0));

        // Initial heights for constructing the wall.
        // Keeping WALL_INITIAL_MIN_HEIGHT near the ellipsoid surface helps
        // prevent precision problems with planes in the shader.
        // Putting the start point of a plane at ApproximateTerrainHeights._defaultMinTerrainHeight,
        // which is a highly conservative bound, usually puts the plane origin several thousands
        // of meters away from the actual terrain, causing floating point problems when checking
        // fragments on terrain against the plane.
        // Ellipsoid height is generally much closer.
        // The initial max height is arbitrary.
        // Both heights are corrected using ApproximateTerrainHeights for computing the actual volume geometry.
        var WALL_INITIAL_MIN_HEIGHT = 0.0;
        var WALL_INITIAL_MAX_HEIGHT = 1000.0;

        /**
         * A description of a polyline on terrain or 3D Tiles. Only to be used with {@link GroundPolylinePrimitive}.
         *
         * @alias GroundPolylineGeometry
         * @constructor
         *
         * @param {Object} options Options with the following properties:
         * @param {Cartesian3[]} options.positions An array of {@link Cartesian3} defining the polyline's points. Heights above the ellipsoid will be ignored.
         * @param {Number} [options.width=1.0] The screen space width in pixels.
         * @param {Number} [options.granularity=9999.0] The distance interval in meters used for interpolating options.points. Defaults to 9999.0 meters. Zero indicates no interpolation.
         * @param {Boolean} [options.loop=false] Whether during geometry creation a line segment will be added between the last and first line positions to make this Polyline a loop.
         * @param {ArcType} [options.arcType=ArcType.GEODESIC] The type of line the polyline segments must follow. Valid options are {@link ArcType.GEODESIC} and {@link ArcType.RHUMB}.
         *
         * @exception {DeveloperError} At least two positions are required.
         *
         * @see GroundPolylinePrimitive
         *
         * @example
         * var positions = Cesium.Cartesian3.fromDegreesArray([
         *   -112.1340164450331, 36.05494287836128,
         *   -112.08821010582645, 36.097804071380715,
         *   -112.13296079730024, 36.168769146801104
         * ]);
         *
         * var geometry = new Cesium.GroundPolylineGeometry({
         *   positions : positions
         * });
         */
        function GroundPolylineGeometry(options) {
            options = defaultValue.defaultValue(options, defaultValue.defaultValue.EMPTY_OBJECT);
            var positions = options.positions;

            //>>includeStart('debug', pragmas.debug);
            if ((!defined.defined(positions)) || (positions.length < 2)) {
                throw new Check.DeveloperError('At least two positions are required.');
            }
            if (defined.defined(options.arcType) && options.arcType !== ArcType.ArcType.GEODESIC && options.arcType !== ArcType.ArcType.RHUMB) {
                throw new Check.DeveloperError('Valid options for arcType are ArcType.GEODESIC and ArcType.RHUMB.');
            }
            //>>includeEnd('debug');

            /**
             * The screen space width in pixels.
             * @type {Number}
             */
            this.width = defaultValue.defaultValue(options.width, 1.0); // Doesn't get packed, not necessary for computing geometry.

            this._positions = positions;

            /**
             * The distance interval used for interpolating options.points. Zero indicates no interpolation.
             * Default of 9999.0 allows centimeter accuracy with 32 bit floating point.
             * @type {Boolean}
             * @default 9999.0
             */
            this.granularity = defaultValue.defaultValue(options.granularity, 9999.0);

            /**
             * Whether during geometry creation a line segment will be added between the last and first line positions to make this Polyline a loop.
             * If the geometry has two positions this parameter will be ignored.
             * @type {Boolean}
             * @default false
             */
            this.loop = defaultValue.defaultValue(options.loop, false);

            /**
             * The type of path the polyline must follow. Valid options are {@link ArcType.GEODESIC} and {@link ArcType.RHUMB}.
             * @type {ArcType}
             * @default ArcType.GEODESIC
             */
            this.arcType = defaultValue.defaultValue(options.arcType, ArcType.ArcType.GEODESIC);

            this._ellipsoid = Cartesian2.Ellipsoid.WGS84;

            // MapProjections can't be packed, so store the index to a known MapProjection.
            this._projectionIndex = 0;
            this._workerName = 'createGroundPolylineGeometry';

            // Used by GroundPolylinePrimitive to signal worker that scenemode is 3D only.
            this._scene3DOnly = false;
        }

        defineProperties.defineProperties(GroundPolylineGeometry.prototype, {
            /**
             * The number of elements used to pack the object into an array.
             * @memberof GroundPolylineGeometry.prototype
             * @type {Number}
             * @readonly
             * @private
             */
            packedLength: {
                get: function() {
                    return 1.0 + this._positions.length * 3 + 1.0 + 1.0 + 1.0 + Cartesian2.Ellipsoid.packedLength + 1.0 + 1.0;
                }
            }
        });

        /**
         * Set the GroundPolylineGeometry's projection and ellipsoid.
         * Used by GroundPolylinePrimitive to signal scene information to the geometry for generating 2D attributes.
         *
         * @param {GroundPolylineGeometry} groundPolylineGeometry GroundPolylinGeometry describing a polyline on terrain or 3D Tiles.
         * @param {Projection} mapProjection A MapProjection used for projecting cartographic coordinates to 2D.
         * @private
         */
        GroundPolylineGeometry.setProjectionAndEllipsoid = function(groundPolylineGeometry, mapProjection) {
            var projectionIndex = 0;
            for (var i = 0; i < PROJECTION_COUNT; i++) {
                if (mapProjection instanceof PROJECTIONS[i]) {
                    projectionIndex = i;
                    break;
                }
            }

            groundPolylineGeometry._projectionIndex = projectionIndex;
            groundPolylineGeometry._ellipsoid = mapProjection.ellipsoid;
        };

        var cart3Scratch1 = new Cartesian2.Cartesian3();
        var cart3Scratch2 = new Cartesian2.Cartesian3();
        var cart3Scratch3 = new Cartesian2.Cartesian3();
        function computeRightNormal(start, end, maxHeight, ellipsoid, result) {
            var startBottom = getPosition(ellipsoid, start, 0.0, cart3Scratch1);
            var startTop = getPosition(ellipsoid, start, maxHeight, cart3Scratch2);
            var endBottom = getPosition(ellipsoid, end, 0.0, cart3Scratch3);

            var up = direction(startTop, startBottom, cart3Scratch2);
            var forward = direction(endBottom, startBottom, cart3Scratch3);

            Cartesian2.Cartesian3.cross(forward, up, result);
            return Cartesian2.Cartesian3.normalize(result, result);
        }

        var interpolatedCartographicScratch = new Cartesian2.Cartographic();
        var interpolatedBottomScratch = new Cartesian2.Cartesian3();
        var interpolatedTopScratch = new Cartesian2.Cartesian3();
        var interpolatedNormalScratch = new Cartesian2.Cartesian3();
        function interpolateSegment(start, end, minHeight, maxHeight, granularity, arcType, ellipsoid, normalsArray, bottomPositionsArray, topPositionsArray, cartographicsArray) {
            if (granularity === 0.0) {
                return;
            }

            var ellipsoidLine;
            if (arcType === ArcType.ArcType.GEODESIC) {
                ellipsoidLine = new EllipsoidGeodesic.EllipsoidGeodesic(start, end, ellipsoid);
            } else if (arcType === ArcType.ArcType.RHUMB) {
                ellipsoidLine = new EllipsoidRhumbLine.EllipsoidRhumbLine(start, end, ellipsoid);
            }

            var surfaceDistance = ellipsoidLine.surfaceDistance;
            if (surfaceDistance < granularity) {
                return;
            }

            // Compute rightwards normal applicable at all interpolated points
            var interpolatedNormal = computeRightNormal(start, end, maxHeight, ellipsoid, interpolatedNormalScratch);

            var segments = Math.ceil(surfaceDistance / granularity);
            var interpointDistance = surfaceDistance / segments;
            var distanceFromStart = interpointDistance;
            var pointsToAdd = segments - 1;
            var packIndex = normalsArray.length;
            for (var i = 0; i < pointsToAdd; i++) {
                var interpolatedCartographic = ellipsoidLine.interpolateUsingSurfaceDistance(distanceFromStart, interpolatedCartographicScratch);
                var interpolatedBottom = getPosition(ellipsoid, interpolatedCartographic, minHeight, interpolatedBottomScratch);
                var interpolatedTop = getPosition(ellipsoid, interpolatedCartographic, maxHeight, interpolatedTopScratch);

                Cartesian2.Cartesian3.pack(interpolatedNormal, normalsArray, packIndex);
                Cartesian2.Cartesian3.pack(interpolatedBottom, bottomPositionsArray, packIndex);
                Cartesian2.Cartesian3.pack(interpolatedTop, topPositionsArray, packIndex);
                cartographicsArray.push(interpolatedCartographic.latitude);
                cartographicsArray.push(interpolatedCartographic.longitude);

                packIndex += 3;
                distanceFromStart += interpointDistance;
            }
        }

        var heightlessCartographicScratch = new Cartesian2.Cartographic();
        function getPosition(ellipsoid, cartographic, height, result) {
            Cartesian2.Cartographic.clone(cartographic, heightlessCartographicScratch);
            heightlessCartographicScratch.height = height;
            return Cartesian2.Cartographic.toCartesian(heightlessCartographicScratch, ellipsoid, result);
        }

        /**
         * Stores the provided instance into the provided array.
         *
         * @param {PolygonGeometry} value The value to pack.
         * @param {Number[]} array The array to pack into.
         * @param {Number} [startingIndex=0] The index into the array at which to start packing the elements.
         *
         * @returns {Number[]} The array that was packed into
         */
        GroundPolylineGeometry.pack = function(value, array, startingIndex) {
            //>>includeStart('debug', pragmas.debug);
            Check.Check.typeOf.object('value', value);
            Check.Check.defined('array', array);
            //>>includeEnd('debug');

            var index = defaultValue.defaultValue(startingIndex, 0);

            var positions = value._positions;
            var positionsLength = positions.length;

            array[index++] = positionsLength;

            for (var i = 0; i < positionsLength; ++i) {
                var cartesian = positions[i];
                Cartesian2.Cartesian3.pack(cartesian, array, index);
                index += 3;
            }

            array[index++] = value.granularity;
            array[index++] = value.loop ? 1.0 : 0.0;
            array[index++] = value.arcType;

            Cartesian2.Ellipsoid.pack(value._ellipsoid, array, index);
            index += Cartesian2.Ellipsoid.packedLength;

            array[index++] = value._projectionIndex;
            array[index++] = value._scene3DOnly ? 1.0 : 0.0;

            return array;
        };

        /**
         * Retrieves an instance from a packed array.
         *
         * @param {Number[]} array The packed array.
         * @param {Number} [startingIndex=0] The starting index of the element to be unpacked.
         * @param {PolygonGeometry} [result] The object into which to store the result.
         */
        GroundPolylineGeometry.unpack = function(array, startingIndex, result) {
            //>>includeStart('debug', pragmas.debug);
            Check.Check.defined('array', array);
            //>>includeEnd('debug');

            var index = defaultValue.defaultValue(startingIndex, 0);
            var positionsLength = array[index++];
            var positions = new Array(positionsLength);

            for (var i = 0; i < positionsLength; i++) {
                positions[i] = Cartesian2.Cartesian3.unpack(array, index);
                index += 3;
            }

            var granularity = array[index++];
            var loop = array[index++] === 1.0;
            var arcType = array[index++];

            var ellipsoid = Cartesian2.Ellipsoid.unpack(array, index);
            index += Cartesian2.Ellipsoid.packedLength;

            var projectionIndex = array[index++];
            var scene3DOnly = (array[index++] === 1.0);

            if (!defined.defined(result)) {
                result = new GroundPolylineGeometry({
                    positions : positions
                });
            }

            result._positions = positions;
            result.granularity = granularity;
            result.loop = loop;
            result.arcType = arcType;
            result._ellipsoid = ellipsoid;
            result._projectionIndex = projectionIndex;
            result._scene3DOnly = scene3DOnly;

            return result;
        };

        function direction(target, origin, result) {
            Cartesian2.Cartesian3.subtract(target, origin, result);
            Cartesian2.Cartesian3.normalize(result, result);
            return result;
        }

        function tangentDirection(target, origin, up, result) {
            result = direction(target, origin, result);

            // orthogonalize
            result = Cartesian2.Cartesian3.cross(result, up, result);
            result = Cartesian2.Cartesian3.normalize(result, result);
            result = Cartesian2.Cartesian3.cross(up, result, result);
            return result;
        }

        var toPreviousScratch = new Cartesian2.Cartesian3();
        var toNextScratch = new Cartesian2.Cartesian3();
        var forwardScratch = new Cartesian2.Cartesian3();
        var vertexUpScratch = new Cartesian2.Cartesian3();
        var cosine90 = 0.0;
        var cosine180 = -1.0;
        function computeVertexMiterNormal(previousBottom, vertexBottom, vertexTop, nextBottom, result) {
            var up = direction(vertexTop, vertexBottom, vertexUpScratch);

            // Compute vectors pointing towards neighboring points but tangent to this point on the ellipsoid
            var toPrevious = tangentDirection(previousBottom, vertexBottom, up, toPreviousScratch);
            var toNext = tangentDirection(nextBottom, vertexBottom, up, toNextScratch);

            // Check if tangents are almost opposite - if so, no need to miter.
            if (_Math.CesiumMath.equalsEpsilon(Cartesian2.Cartesian3.dot(toPrevious, toNext), cosine180, _Math.CesiumMath.EPSILON5)) {
                 result = Cartesian2.Cartesian3.cross(up, toPrevious, result);
                 result = Cartesian2.Cartesian3.normalize(result, result);
                 return result;
            }

            // Average directions to previous and to next in the plane of Up
            result = Cartesian2.Cartesian3.add(toNext, toPrevious, result);
            result = Cartesian2.Cartesian3.normalize(result, result);

            // Flip the normal if it isn't pointing roughly bound right (aka if forward is pointing more "backwards")
            var forward = Cartesian2.Cartesian3.cross(up, result, forwardScratch);
            if (Cartesian2.Cartesian3.dot(toNext, forward) < cosine90) {
                result = Cartesian2.Cartesian3.negate(result, result);
            }

            return result;
        }

        var XZ_PLANE = Plane.Plane.fromPointNormal(Cartesian2.Cartesian3.ZERO, Cartesian2.Cartesian3.UNIT_Y);

        var previousBottomScratch = new Cartesian2.Cartesian3();
        var vertexBottomScratch = new Cartesian2.Cartesian3();
        var vertexTopScratch = new Cartesian2.Cartesian3();
        var nextBottomScratch = new Cartesian2.Cartesian3();
        var vertexNormalScratch = new Cartesian2.Cartesian3();
        var intersectionScratch = new Cartesian2.Cartesian3();
        var cartographicScratch0 = new Cartesian2.Cartographic();
        var cartographicScratch1 = new Cartesian2.Cartographic();
        var cartographicIntersectionScratch = new Cartesian2.Cartographic();
        /**
         * Computes shadow volumes for the ground polyline, consisting of its vertices, indices, and a bounding sphere.
         * Vertices are "fat," packing all the data needed in each volume to describe a line on terrain or 3D Tiles.
         * Should not be called independent of {@link GroundPolylinePrimitive}.
         *
         * @param {GroundPolylineGeometry} groundPolylineGeometry
         * @private
         */
        GroundPolylineGeometry.createGeometry = function(groundPolylineGeometry) {
            var compute2dAttributes = !groundPolylineGeometry._scene3DOnly;
            var loop = groundPolylineGeometry.loop;
            var ellipsoid = groundPolylineGeometry._ellipsoid;
            var granularity = groundPolylineGeometry.granularity;
            var arcType = groundPolylineGeometry.arcType;
            var projection = new PROJECTIONS[groundPolylineGeometry._projectionIndex](ellipsoid);

            var minHeight = WALL_INITIAL_MIN_HEIGHT;
            var maxHeight = WALL_INITIAL_MAX_HEIGHT;

            var index;
            var i;

            var positions = groundPolylineGeometry._positions;
            var positionsLength = positions.length;

            if (positionsLength === 2) {
                loop = false;
            }

            // Split positions across the IDL and the Prime Meridian as well.
            // Split across prime meridian because very large geometries crossing the Prime Meridian but not the IDL
            // may get split by the plane of IDL + Prime Meridian.
            var p0;
            var p1;
            var c0;
            var c1;
            var rhumbLine = new EllipsoidRhumbLine.EllipsoidRhumbLine(undefined, undefined, ellipsoid);
            var intersection;
            var intersectionCartographic;
            var intersectionLongitude;
            var splitPositions = [positions[0]];
            for (i = 0; i < positionsLength - 1; i++) {
                p0 = positions[i];
                p1 = positions[i + 1];
                intersection = IntersectionTests.IntersectionTests.lineSegmentPlane(p0, p1, XZ_PLANE, intersectionScratch);
                if (defined.defined(intersection) &&
                    !Cartesian2.Cartesian3.equalsEpsilon(intersection, p0, _Math.CesiumMath.EPSILON7) &&
                    !Cartesian2.Cartesian3.equalsEpsilon(intersection, p1, _Math.CesiumMath.EPSILON7)) {
                    if (groundPolylineGeometry.arcType === ArcType.ArcType.GEODESIC) {
                        splitPositions.push(Cartesian2.Cartesian3.clone(intersection));
                    } else if (groundPolylineGeometry.arcType === ArcType.ArcType.RHUMB) {
                        intersectionLongitude = ellipsoid.cartesianToCartographic(intersection, cartographicScratch0).longitude;
                        c0 = ellipsoid.cartesianToCartographic(p0, cartographicScratch0);
                        c1 = ellipsoid.cartesianToCartographic(p1, cartographicScratch1);
                        rhumbLine.setEndPoints(c0, c1);
                        intersectionCartographic = rhumbLine.findIntersectionWithLongitude(intersectionLongitude, cartographicIntersectionScratch);
                        intersection = ellipsoid.cartographicToCartesian(intersectionCartographic, intersectionScratch);
                        if (defined.defined(intersection) &&
                            !Cartesian2.Cartesian3.equalsEpsilon(intersection, p0, _Math.CesiumMath.EPSILON7) &&
                            !Cartesian2.Cartesian3.equalsEpsilon(intersection, p1, _Math.CesiumMath.EPSILON7)) {
                            splitPositions.push(Cartesian2.Cartesian3.clone(intersection));
                        }
                    }
                }
                splitPositions.push(p1);
            }

            if (loop) {
                p0 = positions[positionsLength - 1];
                p1 = positions[0];
                intersection = IntersectionTests.IntersectionTests.lineSegmentPlane(p0, p1, XZ_PLANE, intersectionScratch);
                if (defined.defined(intersection) &&
                    !Cartesian2.Cartesian3.equalsEpsilon(intersection, p0, _Math.CesiumMath.EPSILON7) &&
                    !Cartesian2.Cartesian3.equalsEpsilon(intersection, p1, _Math.CesiumMath.EPSILON7)) {
                    if (groundPolylineGeometry.arcType === ArcType.ArcType.GEODESIC) {
                        splitPositions.push(Cartesian2.Cartesian3.clone(intersection));
                    } else if (groundPolylineGeometry.arcType === ArcType.ArcType.RHUMB) {
                        intersectionLongitude = ellipsoid.cartesianToCartographic(intersection, cartographicScratch0).longitude;
                        c0 = ellipsoid.cartesianToCartographic(p0, cartographicScratch0);
                        c1 = ellipsoid.cartesianToCartographic(p1, cartographicScratch1);
                        rhumbLine.setEndPoints(c0, c1);
                        intersectionCartographic = rhumbLine.findIntersectionWithLongitude(intersectionLongitude, cartographicIntersectionScratch);
                        intersection = ellipsoid.cartographicToCartesian(intersectionCartographic, intersectionScratch);
                        if (defined.defined(intersection) &&
                            !Cartesian2.Cartesian3.equalsEpsilon(intersection, p0, _Math.CesiumMath.EPSILON7) &&
                            !Cartesian2.Cartesian3.equalsEpsilon(intersection, p1, _Math.CesiumMath.EPSILON7)) {
                            splitPositions.push(Cartesian2.Cartesian3.clone(intersection));
                        }
                    }
                }
            }
            var cartographicsLength = splitPositions.length;

            var cartographics = new Array(cartographicsLength);
            for (i = 0; i < cartographicsLength; i++) {
                var cartographic = Cartesian2.Cartographic.fromCartesian(splitPositions[i], ellipsoid);
                cartographic.height = 0.0;
                cartographics[i] = cartographic;
            }

            cartographics = arrayRemoveDuplicates.arrayRemoveDuplicates(cartographics, Cartesian2.Cartographic.equalsEpsilon);
            cartographicsLength = cartographics.length;

            if (cartographicsLength < 2) {
                return undefined;
            }

            /**** Build heap-side arrays for positions, interpolated cartographics, and normals from which to compute vertices ****/
            // We build a "wall" and then decompose it into separately connected component "volumes" because we need a lot
            // of information about the wall. Also, this simplifies interpolation.
            // Convention: "next" and "end" are locally forward to each segment of the wall,
            // and we are computing normals pointing towards the local right side of the vertices in each segment.
            var cartographicsArray = [];
            var normalsArray = [];
            var bottomPositionsArray = [];
            var topPositionsArray = [];

            var previousBottom = previousBottomScratch;
            var vertexBottom = vertexBottomScratch;
            var vertexTop = vertexTopScratch;
            var nextBottom = nextBottomScratch;
            var vertexNormal = vertexNormalScratch;

            // First point - either loop or attach a "perpendicular" normal
            var startCartographic = cartographics[0];
            var nextCartographic = cartographics[1];

            var prestartCartographic = cartographics[cartographicsLength - 1];
            previousBottom = getPosition(ellipsoid, prestartCartographic, minHeight, previousBottom);
            nextBottom = getPosition(ellipsoid, nextCartographic, minHeight, nextBottom);
            vertexBottom = getPosition(ellipsoid, startCartographic, minHeight, vertexBottom);
            vertexTop = getPosition(ellipsoid, startCartographic, maxHeight, vertexTop);

            if (loop) {
                vertexNormal = computeVertexMiterNormal(previousBottom, vertexBottom, vertexTop, nextBottom, vertexNormal);
            } else {
                vertexNormal = computeRightNormal(startCartographic, nextCartographic, maxHeight, ellipsoid, vertexNormal);
            }

            Cartesian2.Cartesian3.pack(vertexNormal, normalsArray, 0);
            Cartesian2.Cartesian3.pack(vertexBottom, bottomPositionsArray, 0);
            Cartesian2.Cartesian3.pack(vertexTop, topPositionsArray, 0);
            cartographicsArray.push(startCartographic.latitude);
            cartographicsArray.push(startCartographic.longitude);

            interpolateSegment(startCartographic, nextCartographic, minHeight, maxHeight, granularity, arcType, ellipsoid, normalsArray, bottomPositionsArray, topPositionsArray, cartographicsArray);

            // All inbetween points
            for (i = 1; i < cartographicsLength - 1; ++i) {
                previousBottom = Cartesian2.Cartesian3.clone(vertexBottom, previousBottom);
                vertexBottom = Cartesian2.Cartesian3.clone(nextBottom, vertexBottom);
                var vertexCartographic = cartographics[i];
                getPosition(ellipsoid, vertexCartographic, maxHeight, vertexTop);
                getPosition(ellipsoid, cartographics[i + 1], minHeight, nextBottom);

                computeVertexMiterNormal(previousBottom, vertexBottom, vertexTop, nextBottom, vertexNormal);

                index = normalsArray.length;
                Cartesian2.Cartesian3.pack(vertexNormal, normalsArray, index);
                Cartesian2.Cartesian3.pack(vertexBottom, bottomPositionsArray, index);
                Cartesian2.Cartesian3.pack(vertexTop, topPositionsArray, index);
                cartographicsArray.push(vertexCartographic.latitude);
                cartographicsArray.push(vertexCartographic.longitude);

                interpolateSegment(cartographics[i], cartographics[i + 1], minHeight, maxHeight, granularity, arcType, ellipsoid, normalsArray, bottomPositionsArray, topPositionsArray, cartographicsArray);
            }

            // Last point - either loop or attach a normal "perpendicular" to the wall.
            var endCartographic = cartographics[cartographicsLength - 1];
            var preEndCartographic = cartographics[cartographicsLength - 2];

            vertexBottom = getPosition(ellipsoid, endCartographic, minHeight, vertexBottom);
            vertexTop = getPosition(ellipsoid, endCartographic, maxHeight, vertexTop);

            if (loop) {
                var postEndCartographic = cartographics[0];
                previousBottom = getPosition(ellipsoid, preEndCartographic, minHeight, previousBottom);
                nextBottom = getPosition(ellipsoid, postEndCartographic, minHeight, nextBottom);

                vertexNormal = computeVertexMiterNormal(previousBottom, vertexBottom, vertexTop, nextBottom, vertexNormal);
            } else {
                vertexNormal = computeRightNormal(preEndCartographic, endCartographic, maxHeight, ellipsoid, vertexNormal);
            }

            index = normalsArray.length;
            Cartesian2.Cartesian3.pack(vertexNormal, normalsArray, index);
            Cartesian2.Cartesian3.pack(vertexBottom, bottomPositionsArray, index);
            Cartesian2.Cartesian3.pack(vertexTop, topPositionsArray, index);
            cartographicsArray.push(endCartographic.latitude);
            cartographicsArray.push(endCartographic.longitude);

            if (loop) {
                interpolateSegment(endCartographic, startCartographic, minHeight, maxHeight, granularity, arcType, ellipsoid, normalsArray, bottomPositionsArray, topPositionsArray, cartographicsArray);
                index = normalsArray.length;
                for (i = 0; i < 3; ++i) {
                    normalsArray[index + i] = normalsArray[i];
                    bottomPositionsArray[index + i] = bottomPositionsArray[i];
                    topPositionsArray[index + i] = topPositionsArray[i];
                }
                cartographicsArray.push(startCartographic.latitude);
                cartographicsArray.push(startCartographic.longitude);
            }

            return generateGeometryAttributes(loop, projection, bottomPositionsArray, topPositionsArray, normalsArray, cartographicsArray, compute2dAttributes);
        };

        // If the end normal angle is too steep compared to the direction of the line segment,
        // "break" the miter by rotating the normal 90 degrees around the "up" direction at the point
        // For ultra precision we would want to project into a plane, but in practice this is sufficient.
        var lineDirectionScratch = new Cartesian2.Cartesian3();
        var matrix3Scratch = new Transforms.Matrix3();
        var quaternionScratch = new Transforms.Quaternion();
        function breakMiter(endGeometryNormal, startBottom, endBottom, endTop) {
            var lineDirection = direction(endBottom, startBottom, lineDirectionScratch);

            var dot = Cartesian2.Cartesian3.dot(lineDirection, endGeometryNormal);
            if (dot > MITER_BREAK_SMALL || dot < MITER_BREAK_LARGE) {
                var vertexUp = direction(endTop, endBottom, vertexUpScratch);
                var angle = dot < MITER_BREAK_LARGE ? _Math.CesiumMath.PI_OVER_TWO : -_Math.CesiumMath.PI_OVER_TWO;
                var quaternion = Transforms.Quaternion.fromAxisAngle(vertexUp, angle, quaternionScratch);
                var rotationMatrix = Transforms.Matrix3.fromQuaternion(quaternion, matrix3Scratch);
                Transforms.Matrix3.multiplyByVector(rotationMatrix, endGeometryNormal, endGeometryNormal);
                return true;
            }
            return false;
        }

        var endPosCartographicScratch = new Cartesian2.Cartographic();
        var normalStartpointScratch = new Cartesian2.Cartesian3();
        var normalEndpointScratch = new Cartesian2.Cartesian3();
        function projectNormal(projection, cartographic, normal, projectedPosition, result) {
            var position = Cartesian2.Cartographic.toCartesian(cartographic, projection._ellipsoid, normalStartpointScratch);
            var normalEndpoint = Cartesian2.Cartesian3.add(position, normal, normalEndpointScratch);
            var flipNormal = false;

            var ellipsoid = projection._ellipsoid;
            var normalEndpointCartographic = ellipsoid.cartesianToCartographic(normalEndpoint, endPosCartographicScratch);
            // If normal crosses the IDL, go the other way and flip the result.
            // In practice this almost never happens because the cartographic start
            // and end points of each segment are "nudged" to be on the same side
            // of the IDL and slightly away from the IDL.
            if (Math.abs(cartographic.longitude - normalEndpointCartographic.longitude) > _Math.CesiumMath.PI_OVER_TWO) {
                flipNormal = true;
                normalEndpoint = Cartesian2.Cartesian3.subtract(position, normal, normalEndpointScratch);
                normalEndpointCartographic = ellipsoid.cartesianToCartographic(normalEndpoint, endPosCartographicScratch);
            }

            normalEndpointCartographic.height = 0.0;
            var normalEndpointProjected = projection.project(normalEndpointCartographic, result);
            result = Cartesian2.Cartesian3.subtract(normalEndpointProjected, projectedPosition, result);
            result.z = 0.0;
            result = Cartesian2.Cartesian3.normalize(result, result);
            if (flipNormal) {
                Cartesian2.Cartesian3.negate(result, result);
            }
            return result;
        }

        var adjustHeightNormalScratch = new Cartesian2.Cartesian3();
        var adjustHeightOffsetScratch = new Cartesian2.Cartesian3();
        function adjustHeights(bottom, top, minHeight, maxHeight, adjustHeightBottom, adjustHeightTop) {
            // bottom and top should be at WALL_INITIAL_MIN_HEIGHT and WALL_INITIAL_MAX_HEIGHT, respectively
            var adjustHeightNormal = Cartesian2.Cartesian3.subtract(top, bottom, adjustHeightNormalScratch);
            Cartesian2.Cartesian3.normalize(adjustHeightNormal, adjustHeightNormal);

            var distanceForBottom = minHeight - WALL_INITIAL_MIN_HEIGHT;
            var adjustHeightOffset = Cartesian2.Cartesian3.multiplyByScalar(adjustHeightNormal, distanceForBottom, adjustHeightOffsetScratch);
            Cartesian2.Cartesian3.add(bottom, adjustHeightOffset, adjustHeightBottom);

            var distanceForTop = maxHeight - WALL_INITIAL_MAX_HEIGHT;
            adjustHeightOffset = Cartesian2.Cartesian3.multiplyByScalar(adjustHeightNormal, distanceForTop, adjustHeightOffsetScratch);
            Cartesian2.Cartesian3.add(top, adjustHeightOffset, adjustHeightTop);
        }

        var nudgeDirectionScratch = new Cartesian2.Cartesian3();
        function nudgeXZ(start, end) {
            var startToXZdistance = Plane.Plane.getPointDistance(XZ_PLANE, start);
            var endToXZdistance = Plane.Plane.getPointDistance(XZ_PLANE, end);
            var offset = nudgeDirectionScratch;
            // Larger epsilon than what's used in GeometryPipeline, a centimeter in world space
            if (_Math.CesiumMath.equalsEpsilon(startToXZdistance, 0.0, _Math.CesiumMath.EPSILON2)) {
                offset = direction(end, start, offset);
                Cartesian2.Cartesian3.multiplyByScalar(offset, _Math.CesiumMath.EPSILON2, offset);
                Cartesian2.Cartesian3.add(start, offset, start);
            } else if (_Math.CesiumMath.equalsEpsilon(endToXZdistance, 0.0, _Math.CesiumMath.EPSILON2)) {
                offset = direction(start, end, offset);
                Cartesian2.Cartesian3.multiplyByScalar(offset, _Math.CesiumMath.EPSILON2, offset);
                Cartesian2.Cartesian3.add(end, offset, end);
            }
        }

        // "Nudge" cartographic coordinates so start and end are on the same side of the IDL.
        // Nudge amounts are tiny, basically just an IDL flip.
        // Only used for 2D/CV.
        function nudgeCartographic(start, end) {
            var absStartLon = Math.abs(start.longitude);
            var absEndLon = Math.abs(end.longitude);
            if (_Math.CesiumMath.equalsEpsilon(absStartLon, _Math.CesiumMath.PI, _Math.CesiumMath.EPSILON11)) {
                var endSign = _Math.CesiumMath.sign(end.longitude);
                start.longitude = endSign * (absStartLon - _Math.CesiumMath.EPSILON11);
                return 1;
            } else if (_Math.CesiumMath.equalsEpsilon(absEndLon, _Math.CesiumMath.PI, _Math.CesiumMath.EPSILON11)) {
                var startSign = _Math.CesiumMath.sign(start.longitude);
                end.longitude = startSign * (absEndLon - _Math.CesiumMath.EPSILON11);
                return 2;
            }
            return 0;
        }

        var startCartographicScratch = new Cartesian2.Cartographic();
        var endCartographicScratch = new Cartesian2.Cartographic();

        var segmentStartTopScratch = new Cartesian2.Cartesian3();
        var segmentEndTopScratch = new Cartesian2.Cartesian3();
        var segmentStartBottomScratch = new Cartesian2.Cartesian3();
        var segmentEndBottomScratch = new Cartesian2.Cartesian3();
        var segmentStartNormalScratch = new Cartesian2.Cartesian3();
        var segmentEndNormalScratch = new Cartesian2.Cartesian3();

        var getHeightCartographics = [startCartographicScratch, endCartographicScratch];
        var getHeightRectangleScratch = new Cartesian2.Rectangle();

        var adjustHeightStartTopScratch = new Cartesian2.Cartesian3();
        var adjustHeightEndTopScratch = new Cartesian2.Cartesian3();
        var adjustHeightStartBottomScratch = new Cartesian2.Cartesian3();
        var adjustHeightEndBottomScratch = new Cartesian2.Cartesian3();

        var segmentStart2DScratch = new Cartesian2.Cartesian3();
        var segmentEnd2DScratch = new Cartesian2.Cartesian3();
        var segmentStartNormal2DScratch = new Cartesian2.Cartesian3();
        var segmentEndNormal2DScratch = new Cartesian2.Cartesian3();

        var offsetScratch = new Cartesian2.Cartesian3();
        var startUpScratch = new Cartesian2.Cartesian3();
        var endUpScratch = new Cartesian2.Cartesian3();
        var rightScratch = new Cartesian2.Cartesian3();
        var startPlaneNormalScratch = new Cartesian2.Cartesian3();
        var endPlaneNormalScratch = new Cartesian2.Cartesian3();
        var encodeScratch = new EncodedCartesian3.EncodedCartesian3();

        var encodeScratch2D = new EncodedCartesian3.EncodedCartesian3();
        var forwardOffset2DScratch = new Cartesian2.Cartesian3();
        var right2DScratch = new Cartesian2.Cartesian3();

        var normalNudgeScratch = new Cartesian2.Cartesian3();

        var scratchBoundingSpheres = [new Transforms.BoundingSphere(), new Transforms.BoundingSphere()];

        // Winding order is reversed so each segment's volume is inside-out
        var REFERENCE_INDICES = [
            0, 2, 1, 0, 3, 2, // right
            0, 7, 3, 0, 4, 7, // start
            0, 5, 4, 0, 1, 5, // bottom
            5, 7, 4, 5, 6, 7, // left
            5, 2, 6, 5, 1, 2, // end
            3, 6, 2, 3, 7, 6 // top
        ];
        var REFERENCE_INDICES_LENGTH = REFERENCE_INDICES.length;

        // Decompose the "wall" into a series of shadow volumes.
        // Each shadow volume's vertices encode a description of the line it contains,
        // including mitering planes at the end points, a plane along the line itself,
        // and attributes for computing length-wise texture coordinates.
        function generateGeometryAttributes(loop, projection, bottomPositionsArray, topPositionsArray, normalsArray, cartographicsArray, compute2dAttributes) {
            var i;
            var index;
            var ellipsoid = projection._ellipsoid;

            // Each segment will have 8 vertices
            var segmentCount = (bottomPositionsArray.length / 3) - 1;
            var vertexCount = segmentCount * 8;
            var arraySizeVec4 = vertexCount * 4;
            var indexCount = segmentCount * 36;

            var indices = vertexCount > 65535 ? new Uint32Array(indexCount) : new Uint16Array(indexCount);
            var positionsArray = new Float64Array(vertexCount * 3);

            var startHiAndForwardOffsetX = new Float32Array(arraySizeVec4);
            var startLoAndForwardOffsetY = new Float32Array(arraySizeVec4);
            var startNormalAndForwardOffsetZ = new Float32Array(arraySizeVec4);
            var endNormalAndTextureCoordinateNormalizationX = new Float32Array(arraySizeVec4);
            var rightNormalAndTextureCoordinateNormalizationY = new Float32Array(arraySizeVec4);

            var startHiLo2D;
            var offsetAndRight2D;
            var startEndNormals2D;
            var texcoordNormalization2D;

            if (compute2dAttributes) {
                startHiLo2D = new Float32Array(arraySizeVec4);
                offsetAndRight2D = new Float32Array(arraySizeVec4);
                startEndNormals2D = new Float32Array(arraySizeVec4);
                texcoordNormalization2D = new Float32Array(vertexCount * 2);
            }

            /*** Compute total lengths for texture coordinate normalization ***/
            // 2D
            var cartographicsLength = cartographicsArray.length / 2;
            var length2D = 0.0;

            var startCartographic = startCartographicScratch;
            startCartographic.height = 0.0;
            var endCartographic = endCartographicScratch;
            endCartographic.height = 0.0;

            var segmentStartCartesian = segmentStartTopScratch;
            var segmentEndCartesian = segmentEndTopScratch;

            if (compute2dAttributes) {
                index = 0;
                for (i = 1; i < cartographicsLength; i++) {
                    // Don't clone anything from previous segment b/c possible IDL touch
                    startCartographic.latitude = cartographicsArray[index];
                    startCartographic.longitude = cartographicsArray[index + 1];
                    endCartographic.latitude = cartographicsArray[index + 2];
                    endCartographic.longitude = cartographicsArray[index + 3];

                    segmentStartCartesian = projection.project(startCartographic, segmentStartCartesian);
                    segmentEndCartesian = projection.project(endCartographic, segmentEndCartesian);
                    length2D += Cartesian2.Cartesian3.distance(segmentStartCartesian, segmentEndCartesian);
                    index += 2;
                }
            }

            // 3D
            var positionsLength = topPositionsArray.length / 3;
            segmentEndCartesian = Cartesian2.Cartesian3.unpack(topPositionsArray, 0, segmentEndCartesian);
            var length3D = 0.0;

            index = 3;
            for (i = 1; i < positionsLength; i++) {
                segmentStartCartesian = Cartesian2.Cartesian3.clone(segmentEndCartesian, segmentStartCartesian);
                segmentEndCartesian = Cartesian2.Cartesian3.unpack(topPositionsArray, index, segmentEndCartesian);
                length3D += Cartesian2.Cartesian3.distance(segmentStartCartesian, segmentEndCartesian);
                index += 3;
            }

            /*** Generate segments ***/
            var j;
            index = 3;
            var cartographicsIndex = 0;
            var vec2sWriteIndex = 0;
            var vec3sWriteIndex = 0;
            var vec4sWriteIndex = 0;
            var miterBroken = false;

            var endBottom = Cartesian2.Cartesian3.unpack(bottomPositionsArray, 0, segmentEndBottomScratch);
            var endTop = Cartesian2.Cartesian3.unpack(topPositionsArray, 0, segmentEndTopScratch);
            var endGeometryNormal = Cartesian2.Cartesian3.unpack(normalsArray, 0, segmentEndNormalScratch);

            if (loop) {
                var preEndBottom = Cartesian2.Cartesian3.unpack(bottomPositionsArray, bottomPositionsArray.length - 6, segmentStartBottomScratch);
                if (breakMiter(endGeometryNormal, preEndBottom, endBottom, endTop)) {
                    // Miter broken as if for the last point in the loop, needs to be inverted for first point (clone of endBottom)
                    endGeometryNormal = Cartesian2.Cartesian3.negate(endGeometryNormal, endGeometryNormal);
                }
            }

            var lengthSoFar3D = 0.0;
            var lengthSoFar2D = 0.0;

            // For translating bounding volume
            var sumHeights = 0.0;

            for (i = 0; i < segmentCount; i++) {
                var startBottom = Cartesian2.Cartesian3.clone(endBottom, segmentStartBottomScratch);
                var startTop = Cartesian2.Cartesian3.clone(endTop, segmentStartTopScratch);
                var startGeometryNormal = Cartesian2.Cartesian3.clone(endGeometryNormal, segmentStartNormalScratch);

                if (miterBroken) {
                    startGeometryNormal = Cartesian2.Cartesian3.negate(startGeometryNormal, startGeometryNormal);
                }

                endBottom = Cartesian2.Cartesian3.unpack(bottomPositionsArray, index, segmentEndBottomScratch);
                endTop = Cartesian2.Cartesian3.unpack(topPositionsArray, index, segmentEndTopScratch);
                endGeometryNormal = Cartesian2.Cartesian3.unpack(normalsArray, index, segmentEndNormalScratch);

                miterBroken = breakMiter(endGeometryNormal, startBottom, endBottom, endTop);

                // 2D - don't clone anything from previous segment b/c possible IDL touch
                startCartographic.latitude = cartographicsArray[cartographicsIndex];
                startCartographic.longitude = cartographicsArray[cartographicsIndex + 1];
                endCartographic.latitude = cartographicsArray[cartographicsIndex + 2];
                endCartographic.longitude = cartographicsArray[cartographicsIndex + 3];
                var start2D;
                var end2D;
                var startGeometryNormal2D;
                var endGeometryNormal2D;

                if (compute2dAttributes) {
                    var nudgeResult = nudgeCartographic(startCartographic, endCartographic);
                    start2D = projection.project(startCartographic, segmentStart2DScratch);
                    end2D = projection.project(endCartographic, segmentEnd2DScratch);
                    var direction2D = direction(end2D, start2D, forwardOffset2DScratch);
                    direction2D.y = Math.abs(direction2D.y);

                    startGeometryNormal2D = segmentStartNormal2DScratch;
                    endGeometryNormal2D = segmentEndNormal2DScratch;
                    if (nudgeResult === 0 || Cartesian2.Cartesian3.dot(direction2D, Cartesian2.Cartesian3.UNIT_Y) > MITER_BREAK_SMALL) {
                        // No nudge - project the original normal
                        // Or, if the line's angle relative to the IDL is very acute,
                        // in which case snapping will produce oddly shaped volumes.
                        startGeometryNormal2D = projectNormal(projection, startCartographic, startGeometryNormal, start2D, segmentStartNormal2DScratch);
                        endGeometryNormal2D = projectNormal(projection, endCartographic, endGeometryNormal, end2D, segmentEndNormal2DScratch);
                    } else if (nudgeResult === 1) {
                        // Start is close to IDL - snap start normal to align with IDL
                        endGeometryNormal2D = projectNormal(projection, endCartographic, endGeometryNormal, end2D, segmentEndNormal2DScratch);
                        startGeometryNormal2D.x = 0.0;
                        // If start longitude is negative and end longitude is less negative, relative right is unit -Y
                        // If start longitude is positive and end longitude is less positive, relative right is unit +Y
                        startGeometryNormal2D.y = _Math.CesiumMath.sign(startCartographic.longitude - Math.abs(endCartographic.longitude));
                        startGeometryNormal2D.z = 0.0;
                    } else {
                        // End is close to IDL - snap end normal to align with IDL
                        startGeometryNormal2D = projectNormal(projection, startCartographic, startGeometryNormal, start2D, segmentStartNormal2DScratch);
                        endGeometryNormal2D.x = 0.0;
                        // If end longitude is negative and start longitude is less negative, relative right is unit Y
                        // If end longitude is positive and start longitude is less positive, relative right is unit -Y
                        endGeometryNormal2D.y = _Math.CesiumMath.sign(startCartographic.longitude - endCartographic.longitude);
                        endGeometryNormal2D.z = 0.0;
                    }
                }

                /****************************************
                 * Geometry descriptors of a "line on terrain,"
                 * as opposed to the "shadow volume used to draw
                 * the line on terrain":
                 * - position of start + offset to end
                 * - start, end, and right-facing planes
                 * - encoded texture coordinate offsets
                 ****************************************/

                 /** 3D **/
                var segmentLength3D = Cartesian2.Cartesian3.distance(startTop, endTop);

                var encodedStart = EncodedCartesian3.EncodedCartesian3.fromCartesian(startBottom, encodeScratch);
                var forwardOffset = Cartesian2.Cartesian3.subtract(endBottom, startBottom, offsetScratch);
                var forward = Cartesian2.Cartesian3.normalize(forwardOffset, rightScratch);

                var startUp = Cartesian2.Cartesian3.subtract(startTop, startBottom, startUpScratch);
                startUp = Cartesian2.Cartesian3.normalize(startUp, startUp);
                var rightNormal = Cartesian2.Cartesian3.cross(forward, startUp, rightScratch);
                rightNormal = Cartesian2.Cartesian3.normalize(rightNormal, rightNormal);

                var startPlaneNormal = Cartesian2.Cartesian3.cross(startUp, startGeometryNormal, startPlaneNormalScratch);
                startPlaneNormal = Cartesian2.Cartesian3.normalize(startPlaneNormal, startPlaneNormal);

                var endUp = Cartesian2.Cartesian3.subtract(endTop, endBottom, endUpScratch);
                endUp = Cartesian2.Cartesian3.normalize(endUp, endUp);
                var endPlaneNormal = Cartesian2.Cartesian3.cross(endGeometryNormal, endUp, endPlaneNormalScratch);
                endPlaneNormal = Cartesian2.Cartesian3.normalize(endPlaneNormal, endPlaneNormal);

                var texcoordNormalization3DX = segmentLength3D / length3D;
                var texcoordNormalization3DY = lengthSoFar3D / length3D;

                /** 2D **/
                var segmentLength2D = 0.0;
                var encodedStart2D;
                var forwardOffset2D;
                var right2D;
                var texcoordNormalization2DX = 0.0;
                var texcoordNormalization2DY = 0.0;
                if (compute2dAttributes) {
                    segmentLength2D = Cartesian2.Cartesian3.distance(start2D, end2D);

                    encodedStart2D = EncodedCartesian3.EncodedCartesian3.fromCartesian(start2D, encodeScratch2D);
                    forwardOffset2D = Cartesian2.Cartesian3.subtract(end2D, start2D, forwardOffset2DScratch);

                    // Right direction is just forward direction rotated by -90 degrees around Z
                    // Similarly with plane normals
                    right2D = Cartesian2.Cartesian3.normalize(forwardOffset2D, right2DScratch);
                    var swap = right2D.x;
                    right2D.x = right2D.y;
                    right2D.y = -swap;

                    texcoordNormalization2DX = segmentLength2D / length2D;
                    texcoordNormalization2DY = lengthSoFar2D / length2D;
                }
                /** Pack **/
                for (j = 0; j < 8; j++) {
                    var vec4Index = vec4sWriteIndex + j * 4;
                    var vec2Index = vec2sWriteIndex + j * 2;
                    var wIndex = vec4Index + 3;

                    // Encode sidedness of vertex relative to right plane in texture coordinate normalization X,
                    // whether vertex is top or bottom of volume in sign/magnitude of normalization Y.
                    var rightPlaneSide = j < 4 ? 1.0 : -1.0;
                    var topBottomSide = (j === 2 || j === 3 || j === 6 || j === 7) ? 1.0 : -1.0;

                    // 3D
                    Cartesian2.Cartesian3.pack(encodedStart.high, startHiAndForwardOffsetX, vec4Index);
                    startHiAndForwardOffsetX[wIndex] = forwardOffset.x;

                    Cartesian2.Cartesian3.pack(encodedStart.low, startLoAndForwardOffsetY, vec4Index);
                    startLoAndForwardOffsetY[wIndex] = forwardOffset.y;

                    Cartesian2.Cartesian3.pack(startPlaneNormal, startNormalAndForwardOffsetZ, vec4Index);
                    startNormalAndForwardOffsetZ[wIndex] = forwardOffset.z;

                    Cartesian2.Cartesian3.pack(endPlaneNormal, endNormalAndTextureCoordinateNormalizationX, vec4Index);
                    endNormalAndTextureCoordinateNormalizationX[wIndex] = texcoordNormalization3DX * rightPlaneSide;

                    Cartesian2.Cartesian3.pack(rightNormal, rightNormalAndTextureCoordinateNormalizationY, vec4Index);

                    var texcoordNormalization = texcoordNormalization3DY * topBottomSide;
                    if (texcoordNormalization === 0.0 && topBottomSide < 0.0) {
                        texcoordNormalization = 9.0; // some value greater than 1.0
                    }
                    rightNormalAndTextureCoordinateNormalizationY[wIndex] = texcoordNormalization;

                    // 2D
                    if (compute2dAttributes) {
                        startHiLo2D[vec4Index] = encodedStart2D.high.x;
                        startHiLo2D[vec4Index + 1] = encodedStart2D.high.y;
                        startHiLo2D[vec4Index + 2] = encodedStart2D.low.x;
                        startHiLo2D[vec4Index + 3] = encodedStart2D.low.y;

                        startEndNormals2D[vec4Index] = -startGeometryNormal2D.y;
                        startEndNormals2D[vec4Index + 1] = startGeometryNormal2D.x;
                        startEndNormals2D[vec4Index + 2] = endGeometryNormal2D.y;
                        startEndNormals2D[vec4Index + 3] = -endGeometryNormal2D.x;

                        offsetAndRight2D[vec4Index] = forwardOffset2D.x;
                        offsetAndRight2D[vec4Index + 1] = forwardOffset2D.y;
                        offsetAndRight2D[vec4Index + 2] = right2D.x;
                        offsetAndRight2D[vec4Index + 3] = right2D.y;

                        texcoordNormalization2D[vec2Index] = texcoordNormalization2DX * rightPlaneSide;

                        texcoordNormalization = texcoordNormalization2DY * topBottomSide;
                        if (texcoordNormalization === 0.0 && topBottomSide < 0.0) {
                            texcoordNormalization = 9.0; // some value greater than 1.0
                        }
                        texcoordNormalization2D[vec2Index + 1] = texcoordNormalization;
                    }
                }

                // Adjust height of volume in 3D
                var adjustHeightStartBottom = adjustHeightStartBottomScratch;
                var adjustHeightEndBottom = adjustHeightEndBottomScratch;
                var adjustHeightStartTop = adjustHeightStartTopScratch;
                var adjustHeightEndTop = adjustHeightEndTopScratch;

                var getHeightsRectangle = Cartesian2.Rectangle.fromCartographicArray(getHeightCartographics, getHeightRectangleScratch);
                var minMaxHeights = ApproximateTerrainHeights.getMinimumMaximumHeights(getHeightsRectangle, ellipsoid);
                var minHeight = minMaxHeights.minimumTerrainHeight;
                var maxHeight = minMaxHeights.maximumTerrainHeight;

                sumHeights += minHeight;
                sumHeights += maxHeight;

                adjustHeights(startBottom, startTop, minHeight, maxHeight, adjustHeightStartBottom, adjustHeightStartTop);
                adjustHeights(endBottom, endTop, minHeight, maxHeight, adjustHeightEndBottom, adjustHeightEndTop);

                // Nudge the positions away from the "polyline" a little bit to prevent errors in GeometryPipeline
                var normalNudge = Cartesian2.Cartesian3.multiplyByScalar(rightNormal, _Math.CesiumMath.EPSILON5, normalNudgeScratch);
                Cartesian2.Cartesian3.add(adjustHeightStartBottom, normalNudge, adjustHeightStartBottom);
                Cartesian2.Cartesian3.add(adjustHeightEndBottom, normalNudge, adjustHeightEndBottom);
                Cartesian2.Cartesian3.add(adjustHeightStartTop, normalNudge, adjustHeightStartTop);
                Cartesian2.Cartesian3.add(adjustHeightEndTop, normalNudge, adjustHeightEndTop);

                // If the segment is very close to the XZ plane, nudge the vertices slightly to avoid touching it.
                nudgeXZ(adjustHeightStartBottom, adjustHeightEndBottom);
                nudgeXZ(adjustHeightStartTop, adjustHeightEndTop);

                Cartesian2.Cartesian3.pack(adjustHeightStartBottom, positionsArray, vec3sWriteIndex);
                Cartesian2.Cartesian3.pack(adjustHeightEndBottom, positionsArray, vec3sWriteIndex + 3);
                Cartesian2.Cartesian3.pack(adjustHeightEndTop, positionsArray, vec3sWriteIndex + 6);
                Cartesian2.Cartesian3.pack(adjustHeightStartTop, positionsArray, vec3sWriteIndex + 9);

                normalNudge = Cartesian2.Cartesian3.multiplyByScalar(rightNormal, -2.0 * _Math.CesiumMath.EPSILON5, normalNudgeScratch);
                Cartesian2.Cartesian3.add(adjustHeightStartBottom, normalNudge, adjustHeightStartBottom);
                Cartesian2.Cartesian3.add(adjustHeightEndBottom, normalNudge, adjustHeightEndBottom);
                Cartesian2.Cartesian3.add(adjustHeightStartTop, normalNudge, adjustHeightStartTop);
                Cartesian2.Cartesian3.add(adjustHeightEndTop, normalNudge, adjustHeightEndTop);

                nudgeXZ(adjustHeightStartBottom, adjustHeightEndBottom);
                nudgeXZ(adjustHeightStartTop, adjustHeightEndTop);

                Cartesian2.Cartesian3.pack(adjustHeightStartBottom, positionsArray, vec3sWriteIndex + 12);
                Cartesian2.Cartesian3.pack(adjustHeightEndBottom, positionsArray, vec3sWriteIndex + 15);
                Cartesian2.Cartesian3.pack(adjustHeightEndTop, positionsArray, vec3sWriteIndex + 18);
                Cartesian2.Cartesian3.pack(adjustHeightStartTop, positionsArray, vec3sWriteIndex + 21);

                cartographicsIndex += 2;
                index += 3;

                vec2sWriteIndex += 16;
                vec3sWriteIndex += 24;
                vec4sWriteIndex += 32;

                lengthSoFar3D += segmentLength3D;
                lengthSoFar2D += segmentLength2D;
            }

            index = 0;
            var indexOffset = 0;
            for (i = 0; i < segmentCount; i++) {
                for (j = 0; j < REFERENCE_INDICES_LENGTH; j++) {
                    indices[index + j] = REFERENCE_INDICES[j] + indexOffset;
                }
                indexOffset += 8;
                index += REFERENCE_INDICES_LENGTH;
            }

            var boundingSpheres = scratchBoundingSpheres;
            Transforms.BoundingSphere.fromVertices(bottomPositionsArray, Cartesian2.Cartesian3.ZERO, 3, boundingSpheres[0]);
            Transforms.BoundingSphere.fromVertices(topPositionsArray, Cartesian2.Cartesian3.ZERO, 3, boundingSpheres[1]);
            var boundingSphere = Transforms.BoundingSphere.fromBoundingSpheres(boundingSpheres);

            // Adjust bounding sphere height and radius to cover more of the volume
            boundingSphere.radius += sumHeights / (segmentCount * 2.0);

            var attributes = {
                position : new GeometryAttribute.GeometryAttribute({
                    componentDatatype : ComponentDatatype.ComponentDatatype.DOUBLE,
                    componentsPerAttribute : 3,
                    normalize : false,
                    values : positionsArray
                }),
                startHiAndForwardOffsetX : getVec4GeometryAttribute(startHiAndForwardOffsetX),
                startLoAndForwardOffsetY : getVec4GeometryAttribute(startLoAndForwardOffsetY),
                startNormalAndForwardOffsetZ : getVec4GeometryAttribute(startNormalAndForwardOffsetZ),
                endNormalAndTextureCoordinateNormalizationX : getVec4GeometryAttribute(endNormalAndTextureCoordinateNormalizationX),
                rightNormalAndTextureCoordinateNormalizationY : getVec4GeometryAttribute(rightNormalAndTextureCoordinateNormalizationY)
            };

            if (compute2dAttributes) {
                attributes.startHiLo2D = getVec4GeometryAttribute(startHiLo2D);
                attributes.offsetAndRight2D = getVec4GeometryAttribute(offsetAndRight2D);
                attributes.startEndNormals2D = getVec4GeometryAttribute(startEndNormals2D);
                attributes.texcoordNormalization2D = new GeometryAttribute.GeometryAttribute({
                    componentDatatype : ComponentDatatype.ComponentDatatype.FLOAT,
                    componentsPerAttribute : 2,
                    normalize : false,
                    values : texcoordNormalization2D
                });
            }

            return new GeometryAttribute.Geometry({
                attributes : attributes,
                indices : indices,
                boundingSphere : boundingSphere
            });
        }

        function getVec4GeometryAttribute(typedArray) {
            return new GeometryAttribute.GeometryAttribute({
                componentDatatype : ComponentDatatype.ComponentDatatype.FLOAT,
                componentsPerAttribute : 4,
                normalize : false,
                values : typedArray
            });
        }

        /**
         * Approximates an ellipsoid-tangent vector in 2D by projecting the end point into 2D.
         * Exposed for testing.
         *
         * @param {MapProjection} projection Map Projection for projecting coordinates to 2D.
         * @param {Cartographic} cartographic The cartographic origin point of the normal.
         *   Used to check if the normal crosses the IDL during projection.
         * @param {Cartesian3} normal The normal in 3D.
         * @param {Cartesian3} projectedPosition The projected origin point of the normal in 2D.
         * @param {Cartesian3} result Result parameter on which to store the projected normal.
         * @private
         */
        GroundPolylineGeometry._projectNormal = projectNormal;

    function createGroundPolylineGeometry(groundPolylineGeometry, offset) {
            return ApproximateTerrainHeights.initialize()
                .then(function() {
                    if (defined.defined(offset)) {
                        groundPolylineGeometry = GroundPolylineGeometry.unpack(groundPolylineGeometry, offset);
                    }
                    return GroundPolylineGeometry.createGeometry(groundPolylineGeometry);
                });
        }

    return createGroundPolylineGeometry;

});