//
//  glgrav - OpenGL N-Body gravity simulator
//
//  Copyright (C) 2003  Ian Cowburn (ianc@noddybox.demon.co.uk)
//
//  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 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
//  -------------------------------------------------------------------------
//
//  Particles
//
//
static const char id[]="$Id$";

#include "particles.h"

Particles::Particles(GLfloat alpha_dec, GLfloat alpha_min)
{
    m_alpha_dec=alpha_dec;
    m_alpha_min=alpha_min;
}


Particles::~Particles()
{
}


void Particles::add(GLfloat x1, GLfloat y1, GLfloat z1,
		    GLfloat x2, GLfloat y2, GLfloat z2,
		    GLfloat r, GLfloat g, GLfloat b)
{
    Point p;

    p.x1=x1;
    p.y1=y1;
    p.z1=z1;
    p.x2=x2;
    p.y2=y2;
    p.z2=z2;
    p.r=r;
    p.g=g;
    p.b=b;
    p.a=1.0;

    m_list.push_back(p);
}


void Particles::draw()
{
    list<Point>::iterator i;

    glBegin(GL_LINES);

    for(i=m_list.begin();i!=m_list.end();i++)
	{
	i->a-=m_alpha_dec;

	glColor4f(i->r,i->g,i->b,i->a);
	glVertex3f(i->x1,i->y1,i->z1);
	glVertex3f(i->x2,i->y2,i->z2);
	}

    glEnd();
}


void Particles::update()
{
    list<Point>::iterator i;

    // Delete dead particles
    //
    i=m_list.begin();
    
    while ((i!=m_list.end())&&(i->a<=m_alpha_min))
    	{
	m_list.pop_front();
	i=m_list.begin();
	}

    // Update them
    //
    for(i=m_list.begin();i!=m_list.end();i++)
	i->a-=m_alpha_dec;
}

// END OF FILE //