text: import defaultValue from "./defaultValue.js";
  import defined from "./defined.js";
  import DeveloperError from "./DeveloperError.js";
  
  /**
   * A vertex format defines what attributes make up a vertex.  A VertexFormat can be provided
   * to a {@link Geometry} to request that certain properties be computed, e.g., just position,
   * position and normal, etc.
   *
   * @param {Object} [options] An object with boolean properties corresponding to VertexFormat properties as shown in the code example.
   *
   * @alias VertexFormat
   * @constructor
   *
   * @example
   * // Create a vertex format with position and 2D texture coordinate attributes.
   * var format = new Cesium.VertexFormat({
   *   position : true,
   *   st : true
   * });
   *
   * @see Geometry#attributes
   * @see Packable
   */
  function VertexFormat(options) {
    options = defaultValue(options, defaultValue.EMPTY_OBJECT);
  
    /**
     * When <code>true</code>, the vertex has a 3D position attribute.
     * <p>
     * 64-bit floating-point (for precision).  3 components per attribute.
     * </p>
     *
     * @type Boolean
     *
     * @default false
     */
    this.position = defaultValue(options.position, false);
  
    /**
     * When <code>true</code>, the vertex has a normal attribute (normalized), which is commonly used for lighting.
     * <p>
     * 32-bit floating-point.  3 components per attribute.
     * </p>
     *
     * @type Boolean
     *
     * @default false
     */
    this.normal = defaultValue(options.normal, false);
  
    /**
     * When <code>true</code>, the vertex has a 2D texture coordinate attribute.
     * <p>
     * 32-bit floating-point.  2 components per attribute
     * </p>
     *
     * @type Boolean
     *
     * @default false
     */
    this.st = defaultValue(options.st, false);
  
    /**
     * When <code>true</code>, the vertex has a bitangent attribute (normalized), which is used for tangent-space effects like bump mapping.
     * <p>
     * 32-bit floating-point.  3 components per attribute.
     * </p>
     *
     * @type Boolean
     *
     * @default false
     */
    this.bitangent = defaultValue(options.bitangent, false);
  
    /**
     * When <code>true</code>, the vertex has a tangent attribute (normalized), which is used for tangent-space effects like bump mapping.
     * <p>
     * 32-bit floating-point.  3 components per attribute.
     * </p>
     *
     * @type Boolean
     *
     * @default false
     */
    this.tangent = defaultValue(options.tangent, false);
  
    /**
     * When <code>true</code>, the vertex has an RGB color attribute.
     * <p>
     * 8-bit unsigned byte.  3 components per attribute.
     * </p>
     *
     * @type Boolean
     *
     * @default false
     */
    this.color = defaultValue(options.color, false);
  }
  
  /**
   * An immutable vertex format with only a position attribute.
   *
   * @type {VertexFormat}
   * @constant
   *
   * @see VertexFormat#position
   */
  VertexFormat.POSITION_ONLY = Object.freeze(
    new VertexFormat({
      position: true,
    })
  );
  
  /**
   * An immutable vertex format with position and normal attributes.
   * This is compatible with per-instance color appearances like {@link PerInstanceColorAppearance}.
   *
   * @type {VertexFormat}
   * @constant
   *
   * @see VertexFormat#position
   * @see VertexFormat#normal
   */
  VertexFormat.POSITION_AND_NORMAL = Object.freeze(
    new VertexFormat({
      position: true,
      normal: true,
    })
  );
  
  /**
   * An immutable vertex format with position, normal, and st attributes.
   * This is compatible with {@link MaterialAppearance} when {@link MaterialAppearance#materialSupport}
   * is <code>TEXTURED/code>.
   *
   * @type {VertexFormat}
   * @constant
   *
   * @see VertexFormat#position
   * @see VertexFormat#normal
   * @see VertexFormat#st
   */
  VertexFormat.POSITION_NORMAL_AND_ST = Object.freeze(
    new VertexFormat({
      position: true,
      normal: true,
      st: true,
    })
  );
  
  /**
   * An immutable vertex format with position and st attributes.
   * This is compatible with {@link EllipsoidSurfaceAppearance}.
   *
   * @type {VertexFormat}
   * @constant
   *
   * @see VertexFormat#position
   * @see VertexFormat#st
   */
  VertexFormat.POSITION_AND_ST = Object.freeze(
    new VertexFormat({
      position: true,
      st: true,
    })
  );
  
  /**
   * An immutable vertex format with position and color attributes.
   *
   * @type {VertexFormat}
   * @constant
   *
   * @see VertexFormat#position
   * @see VertexFormat#color
   */
  VertexFormat.POSITION_AND_COLOR = Object.freeze(
    new VertexFormat({
      position: true,
      color: true,
    })
  );
  
  /**
   * An immutable vertex format with well-known attributes: position, normal, st, tangent, and bitangent.
   *
   * @type {VertexFormat}
   * @constant
   *
   * @see VertexFormat#position
   * @see VertexFormat#normal
   * @see VertexFormat#st
   * @see VertexFormat#tangent
   * @see VertexFormat#bitangent
   */
  VertexFormat.ALL = Object.freeze(
    new VertexFormat({
      position: true,
      normal: true,
      st: true,
      tangent: true,
      bitangent: true,
    })
  );
  
  /**
   * An immutable vertex format with position, normal, and st attributes.
   * This is compatible with most appearances and materials; however
   * normal and st attributes are not always required.  When this is
   * known in advance, another <code>VertexFormat</code> should be used.
   *
   * @type {VertexFormat}
   * @constant
   *
   * @see VertexFormat#position
   * @see VertexFormat#normal
   */
  VertexFormat.DEFAULT = VertexFormat.POSITION_NORMAL_AND_ST;
  
  /**
   * The number of elements used to pack the object into an array.
   * @type {Number}
   */
  VertexFormat.packedLength = 6;
  
  /**
   * Stores the provided instance into the provided array.
   *
   * @param {VertexFormat} 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
   */
  VertexFormat.pack = function (value, array, startingIndex) {
    //>>includeStart('debug', pragmas.debug);
    if (!defined(value)) {
      throw new DeveloperError("value is required");
    }
    if (!defined(array)) {
      throw new DeveloperError("array is required");
    }
    //>>includeEnd('debug');
  
    startingIndex = defaultValue(startingIndex, 0);
  
    array[startingIndex++] = value.position ? 1.0 : 0.0;
    array[startingIndex++] = value.normal ? 1.0 : 0.0;
    array[startingIndex++] = value.st ? 1.0 : 0.0;
    array[startingIndex++] = value.tangent ? 1.0 : 0.0;
    array[startingIndex++] = value.bitangent ? 1.0 : 0.0;
    array[startingIndex] = value.color ? 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 {VertexFormat} [result] The object into which to store the result.
   * @returns {VertexFormat} The modified result parameter or a new VertexFormat instance if one was not provided.
   */
  VertexFormat.unpack = function (array, startingIndex, result) {
    //>>includeStart('debug', pragmas.debug);
    if (!defined(array)) {
      throw new DeveloperError("array is required");
    }
    //>>includeEnd('debug');
  
    startingIndex = defaultValue(startingIndex, 0);
  
    if (!defined(result)) {
      result = new VertexFormat();
    }
  
    result.position = array[startingIndex++] === 1.0;
    result.normal = array[startingIndex++] === 1.0;
    result.st = array[startingIndex++] === 1.0;
    result.tangent = array[startingIndex++] === 1.0;
    result.bitangent = array[startingIndex++] === 1.0;
    result.color = array[startingIndex] === 1.0;
    return result;
  };
  
  /**
   * Duplicates a VertexFormat instance.
   *
   * @param {VertexFormat} vertexFormat The vertex format to duplicate.
   * @param {VertexFormat} [result] The object onto which to store the result.
   * @returns {VertexFormat} The modified result parameter or a new VertexFormat instance if one was not provided. (Returns undefined if vertexFormat is undefined)
   */
  VertexFormat.clone = function (vertexFormat, result) {
    if (!defined(vertexFormat)) {
      return undefined;
    }
    if (!defined(result)) {
      result = new VertexFormat();
    }
  
    result.position = vertexFormat.position;
    result.normal = vertexFormat.normal;
    result.st = vertexFormat.st;
    result.tangent = vertexFormat.tangent;
    result.bitangent = vertexFormat.bitangent;
    result.color = vertexFormat.color;
    return result;
  };
  export default VertexFormat;
  