physics/BoundingBox

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/* **-*-c++-*-**************************************************************
  Copyright (C)1996 David Jung <opensim@pobox.com>

  This program/file is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.
  
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details. (http://www.gnu.org)
  
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  
  $Id: BoundingBox 1031 2004-02-11 20:46:36Z jungd $
  $Revision: 1.5 $
  $Date: 2004-02-11 15:46:36 -0500 (Wed, 11 Feb 2004) $
  $Author: jungd $
  
****************************************************************************/

#ifndef _PHYSICS_BOUNDINGBOX_
#define _PHYSICS_BOUNDINGBOX_

#include <physics/physics>

#include <base/Dimension3>
#include <base/Transform>


namespace physics {


class BoundingBox
{
public:
  BoundingBox() {}
  BoundingBox(const BoundingBox& bb) 
    : center(bb.center), extent(bb.extent) {}
  BoundingBox(const base::Point3& lower, const base::Point3& upper)
    { setExtents(lower,upper); }
  ~BoundingBox() {}
  
  base::Point3 lower() const { return center-extent; }
  base::Point3 upper() const { return center+extent; }


  void setExtents(const base::Point3& lower, const base::Point3& upper)
    { extent = (upper-lower)/2.0; center = lower+extent; }

  void setCenter(const base::Point3& center) { this->center=center; }
  void setDimension(const base::Dimension3& dim) { extent = dim/2.0; }
  base::Dimension3 getDimension() const { return extent*2.0; }

  void setEmpty() {
    center=base::Point3();
    extent=base::Vector3(-consts::Infinity,-consts::Infinity,-consts::Infinity);
  }
    
  void enclose(const BoundingBox& a, const BoundingBox& b);
  void include(const base::Point3& p);
  void include(const BoundingBox& bb) { enclose(*this, bb); }

  /// take axis-aligned box represented by *this and transform it by t, yielding a
  ///  non-axis-aliigned box.  *this becomes a new axis-aligned box that encloses the non-aligned box.
  void transform(const base::Transform& t);
  
  // NB: half dimension of enclosing cube
  Real size() const { return Math::maximum(Math::maximum(extent.x,extent.y),extent.z); }

  Int longestAxis() const { return extent.largestAxis(); }

  static bool intersect(const BoundingBox& a, const BoundingBox& b) {
    return (Math::abs(a.center.x - b.center.x) <= (a.extent.x + b.extent.x)) &&
      (Math::abs(a.center.y - b.center.y) <= (a.extent.y + b.extent.y)) &&
      (Math::abs(a.center.z - b.center.z) <= (a.extent.z + b.extent.z));
  }

private:
  base::Point3 center;
  base::Vector3 extent;  // 1/2 dimension
};


} // math

#endif

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