/* 
   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: Benjamin Grauer
   co-programmer: ...
*/

#define DEBUG_SPECIAL_MODULE DEBUG_MODULE_PARTICLE

#include "particle_system.h"

#include "particle_emitter.h"
#include "particle_engine.h"
#include "compiler.h"

using namespace std;


/**
   \brief standard constructor
   \param count the Count of particles in the System
   \param type The Type of the ParticleSystem

   \todo this constructor is not jet implemented - do it
*/
ParticleSystem::ParticleSystem (unsigned int maxCount, PARTICLE_TYPE type)
{
   this->setClassName ("ParticleSystem");

   this->maxCount = maxCount;
   this->count = 0;
   this->particleType = type;
   this->particles = NULL;
   this->setConserve(.8);
   this->setLifeSpan(.1);

   ParticleEngine::getInstance()->addSystem(this);
}


/**
   \brief standard deconstructor

*/
ParticleSystem::~ParticleSystem() 
{
  // delete what has to be deleted here
   ParticleEngine::getInstance()->removeSystem(this);
}

// setting properties
void ParticleSystem::setMaterial(Material* material)
{
  this->material = material;
}

void ParticleSystem::setLifeSpan(float lifeSpan, float randomLifeSpan)
{
  this->lifeSpan = lifeSpan;
  this->randomLifeSpan = randomLifeSpan;
}

void ParticleSystem::setRadius(float startRadius, float endRadius, float randomRadius)
{
  this->startRadius = startRadius;
  this->endRadius = endRadius;
  this->randomRadius = randomRadius;
}

void ParticleSystem::setConserve(float conserve)
{
  if (conserve > 1.0)
    this->conserve = 1.0;
  else if (conserve < 0.0)
    this->conserve = 0.0;
  else
    this->conserve = conserve;
}



void ParticleSystem::tick(float dt)
{
  Particle* tickPart = particles;  // the particle to Tick
  Particle* prevPart = NULL;       // 
  while (likely(tickPart != NULL))
    {
      
      tickPart->position = tickPart->position + tickPart->velocity;
      // many more to come
      




      if (this->conserve < 1.0)
	tickPart->velocity = tickPart->velocity * this->conserve;
      // find out if we have to delete tickPart
      if ((tickPart->timeToLive -= dt) <= 0)
	{
	  // remove the particle from the list
	  if (likely(prevPart != NULL))
	    {
	      prevPart->next = tickPart->next;
	      delete tickPart;
	      tickPart = prevPart->next;
	    }
	  else
	    {
	      prevPart = NULL;
	      this->particles = tickPart->next;
	      delete tickPart;
	      tickPart = this->particles;
	    }
	  --this->count;
	}
      else
	{      
	  prevPart = tickPart;
	  tickPart = tickPart->next;
	}
    }
}

void ParticleSystem::draw(void)
{
  Particle* drawPart = particles;
  if (likely(drawPart != NULL))
    {
      glBegin(GL_POINTS);
      while (likely(drawPart != NULL))
	{
	  // draw in DOT mode
	  glVertex3f(drawPart->position.x, drawPart->position.y, drawPart->position.z);
	  
	  
	  drawPart = drawPart->next;
	}
      glEnd();
    }
}


void ParticleSystem::addParticle(Vector position, Vector velocity, unsigned int data)
{
  if (this->count <= this->maxCount)
    {
      // if it is the first Particle
      if (unlikely(particles == NULL))
	{
	  this->particles = new Particle;
	  this->particles->next = NULL;
	}
      // filling the List from the beginning
      else
	{
	  Particle* tmpPart = new Particle;
	  tmpPart->next = this->particles;
	  this->particles = tmpPart;
	}
      
      particles->timeToLive = this->lifeSpan + (float)(random()/RAND_MAX)* this->randomLifeSpan;
      particles->position = position;
      particles->velocity = velocity;
      //  particle->rotation = ; //! \todo rotation is once again something to be done.
      particles->mass = this->initialMass + (random()/RAND_MAX)* this->randomInitialMass;
      particles->radius = this->startRadius + (random()/RAND_MAX)*this->randomRadius;

      ++this->count;
    }
  else
    PRINTF(4)("maximum count of particles reached not adding any more\n");
}