text: var BoundingSphere=require('./BoundingSphere');
  var Cartesian3=require('./Cartesian3');
  var Check=require('./Check');
  var ComponentDatatype=require('./ComponentDatatype');
  var defaultValue=require('./defaultValue');
  var defined=require('./defined');
  var Geometry=require('./Geometry');
  var GeometryAttribute=require('./GeometryAttribute');
  var GeometryAttributes=require('./GeometryAttributes');
  var PrimitiveType=require('./PrimitiveType');
  var VertexFormat=require('./VertexFormat');
  
      'use strict';
  
      /**
       * Describes geometry representing a plane centered at the origin, with a unit width and length.
       *
       * @alias PlaneGeometry
       * @constructor
       *
       * @param {Object} options Object with the following properties:
       * @param {VertexFormat} [options.vertexFormat=VertexFormat.DEFAULT] The vertex attributes to be computed.
       *
       * @example
       * var planeGeometry = new Cesium.PlaneGeometry({
       *   vertexFormat : Cesium.VertexFormat.POSITION_ONLY
       * });
       */
      function PlaneGeometry(options) {
          options = defaultValue(options, defaultValue.EMPTY_OBJECT);
  
          var vertexFormat = defaultValue(options.vertexFormat, VertexFormat.DEFAULT);
  
          this._vertexFormat = vertexFormat;
          this._workerName = 'createPlaneGeometry';
      }
  
      /**
       * The number of elements used to pack the object into an array.
       * @type {Number}
       */
      PlaneGeometry.packedLength = VertexFormat.packedLength;
  
      /**
       * Stores the provided instance into the provided array.
       *
       * @param {PlaneGeometry} 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
       */
      PlaneGeometry.pack = function(value, array, startingIndex) {
          //>>includeStart('debug', pragmas.debug);
          Check.typeOf.object('value', value);
          Check.defined('array', array);
          //>>includeEnd('debug');
  
          startingIndex = defaultValue(startingIndex, 0);
  
          VertexFormat.pack(value._vertexFormat, array, startingIndex);
  
          return array;
      };
  
      var scratchVertexFormat = new VertexFormat();
      var scratchOptions = {
          vertexFormat: scratchVertexFormat
      };
  
      /**
       * 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 {PlaneGeometry} [result] The object into which to store the result.
       * @returns {PlaneGeometry} The modified result parameter or a new PlaneGeometry instance if one was not provided.
       */
      PlaneGeometry.unpack = function(array, startingIndex, result) {
          //>>includeStart('debug', pragmas.debug);
          Check.defined('array', array);
          //>>includeEnd('debug');
  
          startingIndex = defaultValue(startingIndex, 0);
  
          var vertexFormat = VertexFormat.unpack(array, startingIndex, scratchVertexFormat);
  
          if (!defined(result)) {
              return new PlaneGeometry(scratchOptions);
          }
  
          result._vertexFormat = VertexFormat.clone(vertexFormat, result._vertexFormat);
  
          return result;
      };
  
      var min = new Cartesian3(-0.5, -0.5, 0.0);
      var max = new Cartesian3( 0.5,  0.5, 0.0);
  
      /**
       * Computes the geometric representation of a plane, including its vertices, indices, and a bounding sphere.
       *
       * @param {PlaneGeometry} planeGeometry A description of the plane.
       * @returns {Geometry|undefined} The computed vertices and indices.
       */
      PlaneGeometry.createGeometry = function(planeGeometry) {
          var vertexFormat = planeGeometry._vertexFormat;
  
          var attributes = new GeometryAttributes();
          var indices;
          var positions;
  
          if (vertexFormat.position) {
              // 4 corner points.  Duplicated 3 times each for each incident edge/face.
              positions = new Float64Array(4 * 3);
  
              // +z face
              positions[0]  = min.x;
              positions[1]  = min.y;
              positions[2]  = 0.0;
              positions[3]  = max.x;
              positions[4]  = min.y;
              positions[5]  = 0.0;
              positions[6]  = max.x;
              positions[7]  = max.y;
              positions[8]  = 0.0;
              positions[9]  = min.x;
              positions[10] = max.y;
              positions[11] = 0.0;
  
              attributes.position = new GeometryAttribute({
                  componentDatatype : ComponentDatatype.DOUBLE,
                  componentsPerAttribute : 3,
                  values : positions
              });
  
              if (vertexFormat.normal) {
                  var normals = new Float32Array(4 * 3);
  
                  // +z face
                  normals[0]  = 0.0;
                  normals[1]  = 0.0;
                  normals[2]  = 1.0;
                  normals[3]  = 0.0;
                  normals[4]  = 0.0;
                  normals[5]  = 1.0;
                  normals[6]  = 0.0;
                  normals[7]  = 0.0;
                  normals[8]  = 1.0;
                  normals[9]  = 0.0;
                  normals[10] = 0.0;
                  normals[11] = 1.0;
  
                  attributes.normal = new GeometryAttribute({
                      componentDatatype : ComponentDatatype.FLOAT,
                      componentsPerAttribute : 3,
                      values : normals
                  });
              }
  
              if (vertexFormat.st) {
                  var texCoords = new Float32Array(4 * 2);
  
                  // +z face
                  texCoords[0]  = 0.0;
                  texCoords[1]  = 0.0;
                  texCoords[2]  = 1.0;
                  texCoords[3]  = 0.0;
                  texCoords[4]  = 1.0;
                  texCoords[5]  = 1.0;
                  texCoords[6]  = 0.0;
                  texCoords[7]  = 1.0;
  
                  attributes.st = new GeometryAttribute({
                      componentDatatype : ComponentDatatype.FLOAT,
                      componentsPerAttribute : 2,
                      values : texCoords
                  });
              }
  
              if (vertexFormat.tangent) {
                  var tangents = new Float32Array(4 * 3);
  
                  // +z face
                  tangents[0]  = 1.0;
                  tangents[1]  = 0.0;
                  tangents[2]  = 0.0;
                  tangents[3]  = 1.0;
                  tangents[4]  = 0.0;
                  tangents[5]  = 0.0;
                  tangents[6]  = 1.0;
                  tangents[7]  = 0.0;
                  tangents[8]  = 0.0;
                  tangents[9]  = 1.0;
                  tangents[10] = 0.0;
                  tangents[11] = 0.0;
  
                  attributes.tangent = new GeometryAttribute({
                      componentDatatype : ComponentDatatype.FLOAT,
                      componentsPerAttribute : 3,
                      values : tangents
                  });
              }
  
              if (vertexFormat.bitangent) {
                  var bitangents = new Float32Array(4 * 3);
  
                  // +z face
                  bitangents[0] = 0.0;
                  bitangents[1] = 1.0;
                  bitangents[2] = 0.0;
                  bitangents[3] = 0.0;
                  bitangents[4] = 1.0;
                  bitangents[5] = 0.0;
                  bitangents[6] = 0.0;
                  bitangents[7] = 1.0;
                  bitangents[8] = 0.0;
                  bitangents[9] = 0.0;
                  bitangents[10] = 1.0;
                  bitangents[11] = 0.0;
  
                  attributes.bitangent = new GeometryAttribute({
                      componentDatatype : ComponentDatatype.FLOAT,
                      componentsPerAttribute : 3,
                      values : bitangents
                  });
              }
  
              // 2 triangles
              indices = new Uint16Array(2 * 3);
  
              // +z face
              indices[0] = 0;
              indices[1] = 1;
              indices[2] = 2;
              indices[3] = 0;
              indices[4] = 2;
              indices[5] = 3;
          }
  
          return new Geometry({
              attributes : attributes,
              indices : indices,
              primitiveType : PrimitiveType.TRIANGLES,
              boundingSphere : new BoundingSphere(Cartesian3.ZERO, Math.sqrt(2.0))
          });
      };
  
      module.exports= PlaneGeometry;
  