/* 
   orxonox - the future of 3D-vertical-scrollers

   Copyright (C) 2004 orx

   This program 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, or (at your option)
   any later version.

   ### File Specific:
   main-programmer: Christian Meyer
   co-programmer: ...
*/

#include "camera.h"
#include "world.h"
#include "world_entity.h"

using namespace std;

/**
   \brief creates a Camera
   
   This standard constructor sets all parameters to zero
*/
Camera::Camera (World* world)
{
  this->world = world;
  coord = new Coordinate();

  bound = NULL;
  /* give it some physical live */
  mass = 10;
  acceleration = new Vector(0.0, 0.0, 0.0);
  velocity = new Vector(0.0, 0.0, 0.0);
  cameraMode = NORMAL;
  deltaTime = 3000.0;
  cameraOffset = 1.0;
  cameraOffsetZ = 10.0;
  t = 0.0;

  actual_place.pos.x = 0.0;
  actual_place.pos.y = 10.0;
  actual_place.pos.z = -5.0;
  
  // Initializing Target
  target = new CameraTarget (Vector (0,0,0));
  
}

/**
   \brief default destructor
*/
Camera::~Camera ()
{
}

/**
   \brief time based actualisation of camera parameters
   \param deltaT: The amount of time that has passed in milliseconds
   
   This is called by the World in every time_slice, use it to do fancy time dependant effects (such 
   as smooth camera movement or swaying).
*/
void Camera::time_slice (Uint32 deltaT)
{
  if(t <= deltaTime)
    {t += deltaT;}
  //printf("time is: t=%f\n", t );
  update_desired_place ();
  jump (NULL);
}

/**
   \brief this calculates the location where the track wants the camera to be
   
   This refreshes the placement the camera should have according to the 
   bound entity's position on the track.
*/
void Camera::update_desired_place ()
{
  switch(cameraMode)
    {

    case NORMAL:
      coord->setPosition(world->track->getPos() - world->track->getDir() *10 +Vector (0,0,5), WORLD);
      target->coord->setPosition(world->track->getPos(), WORLD);

      Location lookat;
      if( bound != NULL && world != NULL )
	{
	  bound->get_lookat (&lookat);
	  world->calc_camera_pos (&lookat, &desired_place);
	} 
      else
	{
	  desired_place.pos = Vector (0,0,0);
	  desired_place.rot = Quaternion (); 
	}
      break;
    }
}

/**
   \brief initialize rendering perspective according to this camera
   
   This is called immediately before the rendering cycle starts, it sets all global
   rendering options as well as the GL_PROJECTION matrix according to the camera.
*/
void Camera::apply ()
{
  glMatrixMode (GL_PROJECTION);
  glLoadIdentity ();
  // view
  // TO DO: implement options for frustum generation
  glFrustum(-1.0, 1.0, -1.0, 1.0, 1.5, 250.0);

  // ===== first camera control calculation option
  // rotation
  Vector eye = coord->getPosition(WORLD);
  Vector targetV = target->coord->getPosition(WORLD);

  gluLookAt (eye.x, eye.y, eye.z, 
	     targetV.x, targetV.y, targetV.z, 
	     0,0,1);

  float matrix[4][4];
  actual_place.rot.conjugate().matrix (matrix);
  /* orientation and */
  //  glMultMatrixf ((float*)matrix);
  /*  translation */
  //  glTranslatef (-actual_place.pos.x, -actual_place.pos.y,- actual_place.pos.z);
  //Placement *plBound = bound->get_placement();

  // ===== second camera control calculation option
  /*
    gluLookAt(actual_place.pos.x, actual_place.pos.y, actual_place.pos.z, 
              bound->pos.x, bound->pos.y, bound->pos.z,
              0.0, 0.0, 1.0);
  */    

  glMatrixMode (GL_MODELVIEW);
  glLoadIdentity ();
}

/**
  \brief set the camera position
  \param plc: The Placement to set the camera to 
	
	This will set the actual and desired placement of the camera to plc
*/
void Camera::jump (Placement* plc = NULL)
{
  if( plc == NULL)
    {
      actual_place = desired_place;
      //printf("Camera|jump: camer@ %f, %f, %f\n\n", actual_place.r.x, actual_place.r.y, actual_place.r.z);
    }
  else
    {
      desired_place = *plc;
      actual_place = *plc;
    }
}

/**
  \brief bind the camera to an entity
  \param entity: The enitity to bind the camera to
	
	This sets the focus of the camera to the given entity. This means that it will use the given WorldEntity's
	Location and get_lookat() to determine the viewpoint the camera will render from.
	Note that you cannot bind a camera to a free entity.
*/
void Camera::bind (WorldEntity* entity)
{
  if( entity != NULL)
    {
      if( entity->isFree ()) printf("Cannot bind camera to free entity");
      else 
	{
	  bound = entity;
	}
    } 
}


void Camera::setWorld(World* world)
{
  this->world = world;
}



CameraTarget::CameraTarget ()
{
  coord = new Coordinate();

}

CameraTarget::CameraTarget (Vector pos)
{
  coord->setPosition (pos, WORLD);
}