source: orxonox.OLD/branches/coll_rect/src/lib/collision_reaction/cr_engine.h @ 9889

/*!
 * @file cr_engine.h
 * @brief The collision reaction engine, defining generic collision reactions to collision events
 *
 * some parts of this module are tuned for efficiency. They are probably not self-explenatory anymore :D
 *  - Collision/ CollisionEvent objects recycling: This class contains a class of precached objects of these types
 *      they are used for fast registration of collision events: These objects can be get by the interface functions and
 *      are returned after one cycle automaticly by reseting the cached lists to its initial state. So do not wonder :D
 */

#ifndef _CR_ENGINE_
#define _CR_ENGINE_

#include "base_object.h"

#include <vector>

class WorldEntity;


namespace CoRe
{
  class CollisionHandle;
  class Collision;
  class CollisionEvent;

  //! A default singleton class.
  class CREngine : public BaseObject
  {
    ObjectListDeclaration(CREngine);

  public:
    typedef enum CRType {
      CR_PHYSICS_MOMENTUM   = 0,    //!< physical reaction: conservervation of momentum
      CR_PHYSICS_STEP_BACK,         //!< physical reaction: just go to the last position without collisions
      CR_PHYSICS_GROUND_WALK,       //!< physical reaction: stand on the ground, no movement: simulating simple normal force away from the gravity force
      CR_PHYSICS_FULL_WALK,         //!< physical reaction: walking on the ground (inkl. hills etc)
      CR_PHYSICS_DAMAGE,            //!< physical reaction: daling damage according to the object energy and their structural stability

      CR_OBJECT_DAMAGE,             //!< object raction: deals damage according to the objects specific damage potential (like weapons, nukes, etc.)
      CR_OBJECT_PICKUP,             //!< object rection: calling the objects pickup functions, let them handle the collision (once!)

      CR_VERTEX_TRAFO,              //!< vertex trafo: transforming the vertex according to the damage

      CR_SPECIAL_CALLBACK,          //!< special: call a callback function

      CR_NUMBER
    };

    virtual ~CREngine(void);

    /** @returns a Pointer to the only object of this Class */
    inline static CREngine* getInstance() { if (!singletonRef) singletonRef = new CREngine();  return singletonRef; };

    void reset();


    CollisionHandle* subscribeReaction(WorldEntity* worldEntity, CRType type);

    bool unsubscribeReaction(CollisionHandle* collisionHandle);

    void handleCollisions();

    /** @returns an instance to a collision object. instead of creating new object this ones can be resycled */
    inline Collision* popCollisionObject()
    {
      if( !this->collisionsUnused.empty())
      {
        this->collisionsUsed.push_back(this->collisionsUnused.back()); this->collisionsUnused.pop_back(); return this->collisionsUsed.back();
      }
      else return NULL;
    }


    /** @return an instanco of a CollisionEvent object. instead of creating a new object this ones can be used and resycled */
    inline CollisionEvent* popCollisionEventObject()
    {
      if( !this->collisionEventsUnused.empty())
      {
        this->collisionEventsUsed.push_back(this->collisionEventsUnused.back()); this->collisionEventsUnused.pop_back(); return this->collisionEventsUsed.back();
      }
      else return NULL;
    }

    void debug();


  private:
    CREngine();
    void init();

    void flushCollisions();


  private:
    std::vector<CollisionHandle*>       collisionHandles;         //!< list with the collision handles

    std::vector<Collision*>             collisionsUsed;           //!< a list of used, cached collisions
    std::vector<Collision*>             collisionsUnused;         //!< a list of unused, cached collisions

    std::vector<CollisionEvent*>        collisionEventsUsed;      //!< a list of used, cached collision events
    std::vector<CollisionEvent*>        collisionEventsUnused;    //!< a list of unused, cached collision events

    static CREngine*                    singletonRef;             //!< the reference to the CREngine object (singleton)
  };

}
#endif /* _CR_ENGINE_ */