/*
   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: Patrick Boenzli
*/

#define DEBUG_SPECIAL_MODULE DEBUG_MODULE_GRAPHICS

#include "lense_flare.h"

#include "load_param.h"
#include "factory.h"

#include "glincl.h"
#include "texture.h"

#include "light.h"
#include "state.h"

#include "render2D/billboard.h"

#include "light.h"
#include "camera.h"

using namespace std;

CREATE_FACTORY(LenseFlare, CL_LENSE_FLARE);



/**
 *  default constructor
 * @param root The XML-element to load the LenseFlare from
 */
 LenseFlare::LenseFlare(const TiXmlElement* root)
{
  if (root != NULL)
    this->loadParams(root);

  this->flareMatrix = new float[14];
  /*          length                      image scale */
  this->flareMatrix[0] = 1.0f; this->flareMatrix[1] = 1.0f;
  this->flareMatrix[2] = 0.5f; this->flareMatrix[3] = 0.5f;
  this->flareMatrix[4] = 0.33f; this->flareMatrix[5] = 0.25f;
  this->flareMatrix[6] = 0.125f; this->flareMatrix[7] = 1.0f;
  this->flareMatrix[8] = -0.5f; this->flareMatrix[9] = 0.5f;
  this->flareMatrix[10] = -0.25f; this->flareMatrix[11] = 0.15f;
  this->flareMatrix[12] = -1.82f; this->flareMatrix[13] = 0.25f;

  this->lightSource = (LightManager::getInstance())->getLight(0);
}


/**
 *  destroys a LenseFlare
 */
LenseFlare::~LenseFlare()
{
  std::vector<Billboard*>::iterator it;
  for( it = flares.begin(); it != flares.end(); it++)
    delete (*it);
}


/**
 * @param root The XML-element to load the LenseFlare from
 */
void LenseFlare::loadParams(const TiXmlElement* root)
{
  GraphicsEffect::loadParams(root);

    LoadParam(root, "add-flare-texture", this, LenseFlare, addFlare)
        .describe("adds a lensflare texture to the engine");
}


/**
 * initializes the fog effect
 */
bool LenseFlare::init()
{}


/**
 * activates the fog effect
 */
bool LenseFlare::activate()
{
  this->bActivated = true;
}


/**
 * deactivates the fog effect
 */
bool LenseFlare::deactivate()
{
  this->bActivated = false;
}


/**
 * converts a gl mode char to a GLint
 * @param mode the mode character
 */
GLint LenseFlare::charToFogMode(const char* mode)
{}


/**
 * adds a texture flare
 * @param textureName the name of the flare texture
 *
 *  1st: Texture of the Sun/Light source itself
 *  2nd: Texture of the fist halo
 *  3rd: Texture of small burst
 *  4th: Texture of the second halo
 *  5th: Texutre of the second burst
 *  6th: Texture of the third halo
 *  7th: Texture of the third burst
 */
void LenseFlare::addFlare(const char* textureName)
{
  if( this->flares.size() > LF_MAX_FLARES)
  {
    PRINTF(2)("You tried to add more than %i lense flares, ignoring\n", LF_MAX_FLARES);
    return;
  }

  Billboard* bb = new Billboard(NULL);
  bb->setTexture(textureName);
  bb->setSize(50, 50);
  this->flares.push_back(bb);
  PRINTF(0)("Added a Lenseflare Billboard with texture %s\n", textureName);

  // the first flare belongs to the light source
  if( this->flares.size() == 1 && this->lightSource != NULL)
  {
    bb->setBindNode(static_cast<PNode*>(this->lightSource));
    bb->setVisibility(true);
  }
}


bool LenseFlare::sourceVisible() const
{

  float dist = this->frustumPlane.distancePoint(this->lightSource->getAbsCoor());
  if( dist < 0.0f)
  {
    std::vector<Billboard*>::const_iterator it = flares.begin(); it++;
    for(; it != flares.end(); it++)
      (*it)->setVisibility(true);
    return true;
  }

  std::vector<Billboard*>::const_iterator it = flares.begin(); it++;
  for(; it != flares.end(); it++)
    (*it)->setVisibility(false);

  return false;
}


/**
 * tick the effect
 */
void LenseFlare::tick(float dt)
{
  if( unlikely(!this->bActivated || this->flares.size() == 0))
    return;

  // refetch light source information if needed
  if( unlikely( this->lightSource == NULL))
  {
    this->lightSource = (LightManager::getInstance())->getLight(0);
    if( this->flares.size() > 0)
      this->flares[0]->setBindNode(static_cast<PNode*>(this->lightSource));
  }

    //set the frustum plane
  Vector psTarget = (State::getCameraTarget())->getAbsCoor();
  Vector psCamera = (State::getCamera())->getAbsCoor();
  Vector psCameraDir = psCamera - psTarget;
  //PRINTF(0)("camera Dir: %f %f %f, camera: %f %f %f\n", psCameraDir.x, psCameraDir.y, psCameraDir.z, psCamera.x, psCamera.y, psCamera.z);
  this->frustumPlane = Plane(psCameraDir, Vector(-70.0,0.0,0.0));


  // always update the screen center, it could be, that the window is resized
  this->screenCenter = Vector(State::getResX()/2.0f, State::getResY()/2.0f, 0.0f);
  // flare vector is the direction from the center to the light source
  this->flareVector = this->flares[0]->getAbsCoor2D() - this->screenCenter;
  this->flareVector.z = 0.0f;
  this->distance = this->flareVector.len();
  this->flareVector.normalize();

  // now calculate the new coordinates of the billboards
  std::vector<Billboard*>::iterator it;
  int i;
  for( it = flares.begin(), i = 0; it != flares.end(); it++, i++)
  {
    // set the new position
    if( i == 0)
      continue;

    (*it)->setAbsCoor2D( this->screenCenter + this->flareVector * this->flareMatrix[i * 2] * this->distance);
    (*it)->setSize2D(50.0f * this->flareMatrix[i * 2 + 1], 50.0f * this->flareMatrix[i * 2 + 1]);
    PRINTF(5)("Tick flare %i @ (%f, %f)\n", i, (*it)->getAbsCoor2D().x, (*it)->getAbsCoor2D().y);
    // tick them
    (*it)->tick(dt);
  }
}


/**
 * draws the LenseFlares
 */
void LenseFlare::draw() const
{
  if( !this->bActivated)
    return;

  this->sourceVisible();
}