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

  Copyright (C) 2006 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: hdavid
*/

#include "volfog_effect.h"

#include "util/loading/load_param.h"
#include "util/loading/factory.h"

#include "p_node.h"
#include "state.h"
#include "shell_command.h"

#include "glincl.h"
#include "debug.h"

//#include <GL/glext.h>
#include <SDL.h>

/*
//////////////////////////////////
#ifndef APIENTRY
#define APIENTRY
#endif
#ifndef APIENTRYP
#define APIENTRYP APIENTRY *
#endif
///////////////////////////////////
*/
#define GLX_GLXEXT_PROTOTYPES

#include "class_id_DEPRECATED.h"
ObjectListDefinitionID(VolFogEffect, CL_VOLFOG_EFFECT);
CREATE_FACTORY(VolFogEffect);

SHELL_COMMAND(activate, VolFogEffect, activateFog);
SHELL_COMMAND(deactivate, VolFogEffect, deactivateFog);


//typedef void (APIENTRY * PFNGLFOGCOORDFEXTPROC) (GLfloat coord);    // Declare Function Prototype
//PFNGLFOGCOORDFEXTPROC glFogCoordfEXT = NULL;                        // Our glFogCoordfEXT Function


VolFogEffect::VolFogEffect(const TiXmlElement* root) {
  this->registerObject(this, VolFogEffect::_objectList);

  if (root != NULL)
      this->loadParams(root);

  // Initialize Effect
  this->init();

  // Activate Effect
  if(fogActivate)
    this->activate();
}


VolFogEffect::~VolFogEffect() {
  if(fogActivate)
    this->deactivate();
}

void VolFogEffect::loadParams(const TiXmlElement* root) {
  WeatherEffect::loadParams(root);
}

void VolFogEffect::init() {
  PRINTF(0)("Initalize VolFogEffect\n");
  
  fogColor[0] = 0.6f;
  fogColor[1] = 0.3f;
  fogColor[2] = 0.0f;
  fogColor[3] = 1.0f;

  //fogActivate = false;
fogActivate = true;
}


void VolFogEffect::activate() {
  PRINTF(0)("Activating VolFogEffect\n");
  
  // Test whether the extension exists
  if (!glewIsSupported("GL_EXT_fog_coord"))
  {
    PRINTF(0)("Can't activate volumetric fog, GL_EXT_fog_coord extension is misssing\n");
    return;
  }

  // Set Up Fog 
  //glEnable(GL_FOG);                         // Enable Fog
  glFogi(GL_FOG_MODE, GL_LINEAR);           // Fog Fade Is Linear
  glFogfv(GL_FOG_COLOR, fogColor);          // Set The Fog Color
  glFogf(GL_FOG_START,  1.0f);              // Set The Fog Start
  glFogf(GL_FOG_END,    0.0f);              // Set The Fog End
  glHint(GL_FOG_HINT, GL_NICEST);           // Per-Pixel Fog Calculation


  glFogCoordfEXT = (PFNGLFOGCOORDFEXTPROC) SDL_GL_GetProcAddress("glFogCoordfEXT");

  glFogi(GL_FOG_COORDINATE_SOURCE_EXT, GL_FOG_COORDINATE_EXT);    // Set Fog Based On Vertice Coordinates
  
  fogActivate = true;
}

void VolFogEffect::deactivate() {
  PRINTF(0)("Deactivating VolFogEffect\n");
  
  fogActivate = false;
}


/**
* draws the effect
*/
void VolFogEffect::draw() const {

  if(!fogActivate)
    return;

  glPushAttrib(GL_ENABLE_BIT);
  glDisable(GL_LIGHTING);
  glDisable(GL_BLEND);
glEnable(GL_FOG);                         // Enable Fog
  
  glPushMatrix();
  


glBegin(GL_QUADS);                          // Back Wall
    glFogCoordfEXT( 0.0f); glVertex3f(-2.5f,-2.5f,-15.0f);
    glFogCoordfEXT( 0.0f); glVertex3f( 2.5f,-2.5f,-15.0f);
    glFogCoordfEXT( 0.0f); glVertex3f( 2.5f, 2.5f,-15.0f);
    glFogCoordfEXT( 0.0f); glVertex3f(-2.5f, 2.5f,-15.0f);
  glEnd();

  glBegin(GL_QUADS);                          // Floor
    glFogCoordfEXT( 0.0f); glVertex3f(-2.5f,-2.5f,-15.0f);
    glFogCoordfEXT( 0.0f); glVertex3f( 2.5f,-2.5f,-15.0f);
    glFogCoordfEXT( 1.0f); glVertex3f( 2.5f,-2.5f, 15.0f);
    glFogCoordfEXT( 1.0f); glVertex3f(-2.5f,-2.5f, 15.0f);
  glEnd();

  glBegin(GL_QUADS);                          // Roof
    glFogCoordfEXT( 0.0f); glVertex3f(-2.5f, 2.5f,-15.0f);
    glFogCoordfEXT( 0.0f); glVertex3f( 2.5f, 2.5f,-15.0f);
    glFogCoordfEXT( 1.0f); glVertex3f( 2.5f, 2.5f, 15.0f);
    glFogCoordfEXT( 1.0f); glVertex3f(-2.5f, 2.5f, 15.0f);
  glEnd();

  glBegin(GL_QUADS);                          // Right Wall
    glFogCoordfEXT( 1.0f); glVertex3f( 2.5f,-2.5f, 15.0f);
    glFogCoordfEXT( 1.0f); glVertex3f( 2.5f, 2.5f, 15.0f);
    glFogCoordfEXT( 0.0f); glVertex3f( 2.5f, 2.5f,-15.0f);
    glFogCoordfEXT( 0.0f); glVertex3f( 2.5f,-2.5f,-15.0f);
  glEnd();

  glBegin(GL_QUADS);                          // Left Wall
    glFogCoordfEXT( 1.0f); glVertex3f(-2.5f,-2.5f, 15.0f);
    glFogCoordfEXT( 1.0f); glVertex3f(-2.5f, 2.5f, 15.0f);
    glFogCoordfEXT( 0.0f); glVertex3f(-2.5f, 2.5f,-15.0f);
    glFogCoordfEXT( 0.0f); glVertex3f(-2.5f,-2.5f,-15.0f);
  glEnd();

  glPopMatrix();
  glPopAttrib();
}


/**
* ticks the effect if there is any time dependancy
*/
void VolFogEffect::tick(float dt) {}