//
//  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
//
//  -------------------------------------------------------------------------
//
//  Sparks
//
//
static const char id[]="$Id$";

#include "sparks.h"

Sparks::Sparks(int num, GLfloat alpha_dec, GLfloat alpha_min,
	int len, GLfloat delta)
{
    m_num=max(num,1);
    m_alpha_dec=alpha_dec;
    m_alpha_min=alpha_min;
    m_len=max(len,1);
    m_delta=delta;
}


Sparks::~Sparks()
{
}


void Sparks::add(GLfloat ox, GLfloat oy, GLfloat oz)
{
    int f;
    Point p;

    p.x2=ox;
    p.y2=oy;
    p.z2=oz;
    p.life=m_life;

    for(f=0;f<m_num;f++)
    {
	p.dx=DRand()*m_delta*2-m_delta;
	p.dy=DRand()*m_delta*2-m_delta;
	p.dz=DRand()*m_delta*2-m_delta;

	p.x1=ox+p.dx*m_len;
	p.y1=oy+p.dy*m_len;
	p.z1=oz+p.dz*m_len;

	p.alpha=1.0f;

	m_list.push_back(p);
    }
}


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

    // Delete dead sparks
    //
    i=m_list.begin();

    while ((i!=m_list.end())&&(i->alpha<=m_alpha_min))
    {
	m_list.pop_front();
	i=m_list.begin();
    }

    // Update them
    //
    for(i=m_list.begin();i!=m_list.end();i++)
    {
	i->x1+=i->dx;
	i->y1+=i->dy;
	i->z1+=i->dz;

	i->x2+=i->dx;
	i->y2+=i->dy;
	i->z2+=i->dz;

	i->alpha-=m_alpha_dec;
    }
}


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

    // Draw them
    //
    glBegin(GL_LINES);

    for(i=m_list.begin();i!=m_list.end();i++)
    {
	glColor4f(1.0,1.0,0.0,i->alpha);
	glVertex3f(i->x1,i->y1,i->z1);
	glColor4f(0.5,0.0,0.0,i->alpha);
	glVertex3f(i->x2,i->y2,i->z2);
    }

    glEnd();
}


// END OF FILE //