/*
   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: hdavid, amaechler
*/

#include "volfog_effect.h"

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

#include "glincl.h"

#include "shell_command.h"

#define NUM_PANELS 6	/* number of panels in scene */

typedef struct
{
	float x;
	float y;
	float z;
} world_vector;		/* vertex data */

world_vector vertices[NUM_PANELS*4] = {
	{-50.0, -60.0, 0.0},{50.0, -60.0, 0.0},{50.0, 0.0, 0.0},{-50.0, 0.0, 0.0},
	{-50.0, -60.0, 60.0},{-50.0, -60.0, 0.0},{-50.0, 0.0, 0.0},{-50.0, 0.0, 60.0},
	{-50.0, -60.0, 20.0},{-50.0, -60.0, 60.0},{-50.0, 0.0, 60.0},{-50.0, 0.0, 20.0},
	{50.0, -60.0, 0.0},{50.0, -60.0, 60.0},{50.0, 0.0, 60.0},{50.0, 0.0, 0.0},
	{50.0, -60.0, 60.0},{50.0, -60.0, 20.0},{50.0, 0.0, 20.0},{50.0, 0.0, 60.0},
	{-50.0, -60.0, 60.0},{50.0, -60.0, 60.0},{50.0, -60.0, 0.0},{-50.0, -60.0, 0.0}
};

using namespace std;

CREATE_FACTORY(VolFogEffect, CL_VOLFOG_EFFECT);

VolFogEffect::VolFogEffect(const TiXmlElement* root)
{
  this->setClassID(CL_VOLFOG_EFFECT, "VolFogEffect");

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


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


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

  LoadParam(root, "fog-altitude", this, VolFogEffect, setFogAltitude);
  LoadParam(root, "fog-color", this, VolFogEffect, startFogColor);
}


bool VolFogEffect::init()
{
  PRINTF(0)("Initalize VolFogEffect\n");
};



bool VolFogEffect::activate()
{
  PRINTF(0)( "Enabling Volumetric Fog Effect, altitude: %i, color %f, %f, %f\n", this->fogAltitude, this->colorVector.x, this->colorVector.y, this->colorVector.z);

}

bool VolFogEffect::deactivate()
{
  PRINTF(0)("Deactivate VolFogEffect\n");
}


void VolFogEffect::setFogColor(int v)
{
	float z;	/* distance of vertex from edge of fog volume */
	float f;	/* fog factor */

	z = 0.0 - vertices[v].y;
	f = (60.0 - z) / (60.0 - 0.0);	/* linear fog: f = (end - z)/(end - start) */
	glColor4f(this->colorVector.x, this->colorVector.y, this->colorVector.z, f);
}

// int v;		/* store of next vertex ref */

/**
 * draws the effect, if needed
 */
void VolFogEffect::draw() const
{
	int v;		/* store of next vertex ref */
	int ref;

	PRINTF(0)("DRAW VolFogEffect\n");

	for (ref=0; ref<NUM_PANELS; ref++) {

		/* disable writes to z buffer (if fog area) */
		glDepthMask(GL_FALSE);
	
		/* restore z buffer writes, set blend params & disable texturing */

		glDepthMask(GL_TRUE);
		glEnable(GL_BLEND);
		glBlendFunc(GL_ONE_MINUS_SRC_ALPHA, GL_SRC_ALPHA);
		glDisable(GL_TEXTURE_2D);

		/* draw the fog panel */

		v = ref * 4;
		glBegin(GL_QUADS);
		//this->setFogColor(v);
		glVertex3f(vertices[v].x, vertices[v].y, vertices[v].z); v++;
		//this->setFogColor(v);
		glVertex3f(vertices[v].x, vertices[v].y, vertices[v].z); v++;
		//this->setFogColor(v);
		glVertex3f(vertices[v].x, vertices[v].y, vertices[v].z); v++;
		//this->setFogColor(v);
		glVertex3f(vertices[v].x, vertices[v].y, vertices[v].z);
		glEnd();

		/* restore rendering state */

		glEnable(GL_TEXTURE_2D);
		glDisable(GL_BLEND);
	}

	
}



/**
 * ticks the effect if there is any time dependancy
 */
void VolFogEffect::tick(float dt)	
{
  PRINTF(0)("TICK VolFogEffect\n");
}