physics/GJKCollisionDetector

Go to the documentation of this file.

/****************************************************************************
  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: GJKCollisionDetector 1031 2004-02-11 20:46:36Z jungd $
  $Revision: 1.6 $
  $Date: 2004-02-11 15:46:36 -0500 (Wed, 11 Feb 2004) $
  $Author: jungd $
 
****************************************************************************/

#ifndef _PHYSICS_GJKCOLLISIONDETECTOR_
#define _PHYSICS_GJKCOLLISIONDETECTOR_

#include <physics/physics>
#include <base/array>
#include <physics/CollisionDetector>
#include <physics/GJKCollisionModel>
#include <base/Transform>

#include <osg/Array>


namespace physics {


class GJKCollisionDetector : public CollisionDetector
{
public:
  GJKCollisionDetector();
  virtual ~GJKCollisionDetector();

  virtual String className() const { return String("GJKCollisionDetector"); }
  virtual Object& clone() const { return *NewNamedObj(className()) GJKCollisionDetector(); }

  virtual CollisionModel::CollisionModelType getType() const
    { return CollisionModel::GJKModel; }

  virtual bool collision(ref<const Solid> solid1, ref<const Solid> solid2, CollisionQueryType queryType);
  
  
  virtual bool collisionEnable(bool enabled) 
    {
      bool oldEnable = collisionDetectionEnabled;
      collisionDetectionEnabled=enabled; 
      return oldEnable;
    }
  
  // Visual
  virtual bool visualTypeSupported(VisualType type) const { return (type==Visual::OSGVisual); }

  virtual osg::Node* createOSGVisual(Visual::Attributes visualAttributes=0) const;

  
protected:
  bool collisionDetectionEnabled;
  
  virtual ref<CollisionState> newCollisionState(ref<const Solid> solid1, ref<const Solid> solid2) const;

  
  class GJKCollisionState : public CollisionState
  {
  public:
    GJKCollisionState(ref<const Solid> solid1, ref<const Solid> solid2, CollisionModel::CollisionModelType modelType);
    virtual ~GJKCollisionState();

    Vector3 v;
    ref<const Polyhedron::Vertex> lastSupport[2]; /// remember the last support vertices
    Point3 lastSupportPoint[2];                   /// and their local coords.

    virtual String className() const { return String("GJKCollisionState"); }
  };


  // GJK algorithm proper
  bool intersect(ref<const GJKCollisionModel> model1, ref<const GJKCollisionModel> model2,
                 const base::Transform& t1, const base::Transform& t2, 
                 ref<GJKCollisionModel::GJKModelState> modelState1,
                 ref<GJKCollisionModel::GJKModelState> modelState2,
                 ref<GJKCollisionState> collisionState);

  bool closest(Vector3& v);
  void compute_vector(Int bits, Vector3& v);
  void compute_points(int bits, Point3& p1, Point3& p2);
  bool valid(Int s);
  void compute_det();


  Point3  p[4];    // support points of object A in local coordinates 
  Point3  q[4];    // support points of object B in local coordinates 
  Vector3 y[4];    // support points of A - B in world coordinates
  
  Int bits;      // identifies current simplex
  Int last;      // identifies last found support point
  Int last_bit;  // last_bit = 1<<last
  Int all_bits;  // all_bits = bits|last_bit 
  
  Real det[16][4]; // cached sub-determinants

  mutable Visual::Attributes attributes;
  mutable ref_ptr<osg::Node> node;
  mutable osg::Vec3Array* verts;
  mutable osg::ref_ptr<osg::Geometry> geom;
};


} // physics

#endif

---