/*
 * Copyright 2010, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


/**
 * An Element manages DrawElements for classes inherited from Element.
 *
 * @param {!o3d.Material} opt_material The Material used by this Element.
 * @param {!o3d.BoundingBox} opt_boundingBox The BoundingBox used by this
 *     Element for culling.
 * @param {!o3d.Point3} opt_zSortPoint The point to sort by when rendering
 *     this Element in a z ordered DrawPass.
 * @param {boolean} opt_cull Whether or not to attempt to cull this
 *     Element based on whether or not its bounding box is in the view
 *     frustum.
 * @constructor
 */
o3d.Element =
    function(opt_material, opt_boundingBox, opt_zSortPoint, opt_cull) {
  o3d.ParamObject.call(this);

  /**
   * The Material for this element.
   * @type {o3d.Material}
   */
  this.material = opt_material;

  /**
   * The BoundingBox for this element. If culling is on this bounding
   * box will be tested against the view frustum of any draw context
   * used to render this Element.
   * @type {o3d.BoundingBox}
   */
  this.boundingBox = opt_boundingBox ||
      new o3d.BoundingBox([-1, -1, -1], [1, 1, 1]);

  /**
   * The z sort point for this element. If this Element is drawn by a DrawPass
   * that is set to sort by z order this value will be multiplied by the
   * worldViewProjection matrix to compute a z value to sort by.
   * @type {o3d.Point3}
   */
  this.zSortPoint = opt_zSortPoint || [0, 0, 0];

  /**
   * The priority for this element. Used to sort if this Element is drawn by a
   * DrawPass that is set to sort by priority.
   * @type {number}
   */
  this.priority = 0;

  /**
   * The cull settings for this element. If true this Element will be
   * culled by the bounding box above compared to the view frustum it
   * is being rendered with.
   *
   * @type {boolean}
   */
  this.cull = opt_cull || false;

  /**
   * The current owner of this Draw Element. Pass in null to stop
   * being owned.
   *
   * Note: Elements are referenced by the Pack they are created in and
   * their owner. If the Element is removed from its Pack, then
   * setting the owner to null will free the Element. Or, visa versa,
   * if you set the Element's owner to null then removing it from its
   * Pack will free the Element.
   *
   * @type {o3d.Element}
   */
  this.owner_ = null;

  /**
   * Gets all the DrawElements under this Element.
   *
   * Each access to this field gets the entire list so it is best to get it
   * just once. For example:
   *
   * var drawElements = element.drawElements;
   * for (var i = 0; i < drawElements.length; i++) {
   *   var drawElement = drawElements[i];
   * }
   *
   *
   * Note that modifications to this array [e.g. push()] will not affect
   * the underlying Element, while modifications to the members of the array.
   * will affect them.
   *
   * @type {!Array.<!o3d.DrawElement>}
   */
  this.drawElements = [];
};
o3d.inherit('Element', 'ParamObject');

o3d.ParamObject.setUpO3DParam_(o3d.Element, 'material', 'ParamMaterial');
o3d.ParamObject.setUpO3DParam_(o3d.Element, 'boundingBox', 'ParamBoundingBox');
o3d.ParamObject.setUpO3DParam_(o3d.Element, 'zSortPoint', 'ParamFloat3');
o3d.ParamObject.setUpO3DParam_(o3d.Element, 'priority', 'ParamFloat');
o3d.ParamObject.setUpO3DParam_(o3d.Element, 'cull', 'ParamBoolean');

o3d.Element.prototype.__defineSetter__('owner',
    function(o) {
      this.owner_ = o;
      o.addElement(this);
    }
);

o3d.Element.prototype.__defineGetter__('owner',
    function() {
      return this.owner_;
    }
);

/**
 * Creates a DrawElement for this Element. Note that unlike
 * Shape.createDrawElements and Transform.createDrawElements this one will
 * create more than one element for the same material.
 *
 * @param {!o3d.Pack} pack pack used to manage created DrawElement.
 * @param {!o3d.Material} material material to use for DrawElement.
 *     Note: When a DrawElement with a material of null is rendered, the
 *     material on the corresponding Element will get used instead.
 *     This allows you to easily setup the default (just draw as is) by passing
 *     null or setup a shadow pass by passing in a shadow material.
 * @return {!o3d.DrawElement} The created draw element.
 */
o3d.Element.prototype.createDrawElement =
    function(pack, material) {
  drawElement = pack.createObject('DrawElement');
  drawElement.owner = this;
  drawElement.material = material;
  this.drawElements.push(drawElement);
  return drawElement;
};


/**
 * Computes the intersection of a ray in the same coordinate system as
 * the specified POSITION stream.
 * @param {number} position_stream_index Index of POSITION stream.
 * @param {o3d.Cull} cull which side of the triangles to ignore.
 * @param {!o3d.math.Point3} start position of start of ray in local space.
 * @param {!o3d.math.Point3} end position of end of ray. in local space.
 * @return {!o3d.RayIntersectionInfo}  RayIntersectionInfo class. If valid()
 *     is false then something was wrong, Check GetLastError(). If
 *     intersected() is true then the ray intersected a something. position()
 *     is the exact point of intersection.
 */
o3d.Element.prototype.intersectRay =
    function(position_stream_index, cull, start, end) {
  o3d.notImplemented();
};


/**
 * Computes the bounding box in same coordinate system as the specified
 * POSITION stream.
 * @param {number} position_stream_index Index of POSITION stream.
 * @return {!o3d.BoundingBox}  The boundingbox for this element in local space.
 */
o3d.Element.prototype.getBoundingBox =
    function(position_stream_index) {
  return this.boundingBox;
};


/**
 * Virtual function that renders the element.
 */
o3d.Element.prototype.render = function() { };