/*
    Amiga port by Oliver Gantert

    27.04.2000 - fixed some compiler warnings
*/
/*

ORBIT, a freeware space combat simulator
Copyright (C) 1999  Steve Belczyk <steve1@genesis.nred.ma.us>

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.

*/

#include "orbit.h"
#include "stars.h"

/*
 *  Stuff for the background starfield
 */

void ReadStars()
/*
 *  Read in the stellar database
 */
{
  int i;
  double magmin, magmax;

  for (i=0; i<NSTARS; i++)
  {
    star[i].x = stars[i][0];
    star[i].y = stars[i][1];
    star[i].z = stars[i][2];
    star[i].mag = stars[i][3];

    /* Reverse "magnitude" of magnitude (smaller mag means brighter star!) */
    star[i].mag = 0.0 - star[i].mag;

    if (i == 0)
    {
      magmin = magmax = star[i].mag;
    }
    else
    {
      if (star[i].mag < magmin) magmin = star[i].mag;
      if (star[i].mag > magmax) magmax = star[i].mag;
    }
  }

  /* Set the magnitudes */
  for (i=0; i<NSTARS; i++)
  {
    star[i].bright = (star[i].mag - magmin) / (magmax - magmin);
  }

  /* Find magnitude limits for sparse list */
  for (i=0; i<NSTARS/10; i++)
  {
    if (i == 0)
    {
      magmin = magmax = star[i].mag;
    }
    else
    {
      if (star[i].mag < magmin) magmin = star[i].mag;
      if (star[i].mag > magmax) magmax = star[i].mag;
    }
  }

  for (i=0; i<NSTARS/10; i++)
  {
    star[i].bright2 = (star[i].mag - magmin) / (magmax - magmin);
  }
}

void DrawStars()
/*
 *  "My god.  It's full of stars."
 */
{
  /* Turn off 3D stuff */
  glDisable (GL_DEPTH_TEST);
  /* glDisable (GL_CULL_FACE); */
  glDisable (GL_LIGHTING);
  glDepthMask (GL_FALSE);
  /* glDisable (GL_LIGHT0); */

  glPointSize (1);

  glCallList (star_list);

  /* Re-enable three-D stuff */
  glEnable (GL_DEPTH_TEST);
  /* glEnable (GL_CULL_FACE); */
  glEnable (GL_LIGHTING);
  glDepthMask (GL_TRUE);
  /* glEnable (GL_LIGHT0); */
}

void MakeStarList()
/*
 *  Construct display list for starfield
 */
{
  int i, j;

  /* Make dense star field list */
  star_list_dense = glGenLists (1);
  glNewList (star_list_dense, GL_COMPILE);
  glBegin (GL_POINTS);

  for (j=0; j<NSTARS; j++)
  {
    /* Plot stars backwards so bright ones plotted last */
    i = (NSTARS - j) - 1;

    glColor3d (star[i].bright, star[i].bright, star[i].bright);
    /*  glVertex4d (star[i].x, star[i].y, star[i].z, 0.00000); */
    glVertex4d (star[i].x, star[i].y, star[i].z, 0.001);
  }

  glEnd ();
  glEndList();

  /* Make sparse list */
  star_list_sparse = glGenLists (1);
  glNewList (star_list_sparse, GL_COMPILE);
  glBegin (GL_POINTS);

  for (j=0; j<(NSTARS/10); j++)
  {
    i = (NSTARS/10 - j) - 1;
    glColor3d (star[i].bright2, star[i].bright2, star[i].bright2);
    glVertex4d (star[i].x, star[i].y, star[i].z, 0.001);
  }

  glEnd ();
  glEndList();

  star_list = star_list_sparse;
  if (starfield == 2) star_list = star_list_dense;
}