physics/GJKCollisionModel

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/****************************************************************************
  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: GJKCollisionModel 1031 2004-02-11 20:46:36Z jungd $
  $Revision: 1.4 $
  $Date: 2004-02-11 15:46:36 -0500 (Wed, 11 Feb 2004) $
  $Author: jungd $
 
****************************************************************************/

#ifndef _PHYSICS_GJKCOLLISIONMODEL_
#define _PHYSICS_GJKCOLLISIONMODEL_

#include <physics/physics>
#include <physics/CollisionModel>

#include <physics/Box>
#include <physics/Sphere>
#include <physics/Polyhedron>

#include <gfx/TriangleContainer>


namespace physics {


class GJKCollisionModel : public CollisionModel
{
public:
  GJKCollisionModel(const GJKCollisionModel& cm);
  GJKCollisionModel(const gfx::TriangleContainer& triangles);
  GJKCollisionModel(ref<const Shape> shape);
  virtual ~GJKCollisionModel();

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

  virtual CollisionModelType getType() const { return GJKModel; }

 
  class GJKModelState : public ModelState
  {
  public:
    GJKModelState() {}
    GJKModelState(ref<const Polyhedron::Vertex> v)
      : lastSupport(v) {}
    virtual ~GJKModelState() {}

    virtual String className() const { return String("GJKCollisionModel::GJKModelState"); }
    virtual base::Object& clone() const { return *NewNamedObj(className()) GJKModelState(); }
 
    ref<const Polyhedron::Vertex> lastSupport; /// last support vertex of the GJK algorithm
    Point3 lastSupportPoint;                   /// actual local coords. of lastSupport 
  };


protected:
  ref<const Shape> shape; // model is based on this shape
 

  // GJK algorithm Support mapping functions
  void initSupportFunction();
  base::Point3 support(ref<GJKModelState> s, const base::Vector3& v) const
  { 
    Assert(supportFunction);
    s->lastSupportPoint = (*supportFunction)(s,v);
    return s->lastSupportPoint;
  }

  struct SupportFunction : public std::binary_function<ref<GJKModelState>, const base::Vector3&, base::Point3>
  {
    SupportFunction() {}
    virtual ~SupportFunction() {}
    virtual Point3 operator()(ref<GJKModelState> s, const Vector3& v) const = 0;
  };


  struct BoxSupport : public SupportFunction
  {
    BoxSupport(ref<const Shape> s) : box(base::dynamic_cast_ref<const Box>(s)) {}
    virtual Point3 operator()(ref<GJKModelState> s, const Vector3& v) const;
    ref<const Box> box;
  };

  struct SphereSupport : public SupportFunction
  {
    SphereSupport(ref<const Shape> s) : sphere(base::dynamic_cast_ref<const Sphere>(s)) {}
    virtual Point3 operator()(ref<GJKModelState> s, const Vector3& v) const;
    ref<const Sphere> sphere;
  };

  struct PolyhedronSupport : public SupportFunction
  {
    PolyhedronSupport(ref<const Shape> s) : poly(base::dynamic_cast_ref<const Polyhedron>(s)) {}
    virtual Point3 operator()(ref<GJKModelState> s, const Vector3& v) const;
    ref<const Polyhedron> poly;
  };


  SupportFunction* supportFunction; // instantiated support function from above

  
  friend class GJKCollisionDetector;
};


} // physics

#endif

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