/*! 
    \file camera.h
    \brief Viewpoint controlling class definitions
*/ 

#ifndef CAMERA_H
#define CAMERA_H

#include "stdincl.h"

class WorldEntity;
class World;
class CameraTarget;

//! Camera
/**
   This class controls the viewpoint from which the World is rendered. To use the 
   Camera it has to be bound to a WorldEntity which serves as the reference focus 
   point. The Camera itself calls the WorldEntity::get_lookat() and 
   World::calc_camera_pos() functions to calculate the position it currently should
   be in.
*/

enum CAMERA_MODE {NORMAL, SMOTH_FOLLOW, STICKY, ELLIPTICAL};

class Camera
{
 private:
  WorldEntity* bound;		//!< the WorldEntity the Camera is bound to
  Placement actual_place;	        //!< the Camera's current position
  Placement desired_place;        //!< where the Camera should be according to calculations
  World* world;

  CameraTarget* target;
  
  /* physical system - not needed yet */
  float mass;            //!< mass
  Vector *acceleration;  //!< acceleration
  Vector *velocity;      //!< velocity
  
  /* elliptical camera mode variables */
  Placement plLastBPlace;
  float cameraOffset;
  float cameraOffsetZ;
  float deltaTime;
  float t;
  Vector r;
  float rAbs;
  float ka;
  float a0;

  Quaternion *from;
  Quaternion *to;
  Quaternion *res;
  
  
  CAMERA_MODE cameraMode; //!< saves the camera mode: how the camera follows the entity
  
  void update_desired_place ();
  
 public:
  Coordinate* coord;

  Camera (World* world);
  ~Camera ();
  
  void time_slice (Uint32 deltaT);
  void apply ();
  void bind (WorldEntity* entity);
  void jump (Placement* plc);

  void setWorld(World* world);  

};

//! A Class to handle the Target of a Camera.
class CameraTarget
{
 private:
  WorldEntity* lookAt;
  
  
 public:
  Coordinate* coord;
  CameraTarget ();
  CameraTarget (Vector pos); //!< a target only needs a Position and no Rotation

  void setLookAt (WorldEntity* lookat);

};

#endif