/*
    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"

static float ambient[]         =   {
  0.0, 0.0, 0.0, 1.0 }
;
static float diffuse[]         =   {
  1.0, 1.0, 0.0, 1.0 }
;
static float position0[]       =   {
  0.0, 0.0, 0.0, 1.0 }
;
static float lmodel_ambient[]  =   {
  0.01, 0.01, 0.01, 1.0 }
;
static float lmodel_twoside[]  =   {
  GL_TRUE}
;
static float front_shininess[] =   {
  50.0}
;
static float front_specular[]  =   {
  1.0, 1.0, 1.0, 1.0 }
; 
/* static float front_specular[]  =   { 0.0, 0.7, 0.0, 1.0 }; */

void Lights()
{
  int l;
  double v[3];
  float f[3];

  /* Enable depth buffer (why is this *here*?) */
  glDepthFunc (GL_LEQUAL);
  glEnable (GL_DEPTH_TEST);

  /* Turn off ambient light */
  glLightModelfv (GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
  glLightfv (GL_LIGHT0, GL_AMBIENT, lmodel_ambient);

  /* Define light0, the big, main light */
  /* glLightfv (GL_LIGHT0, GL_POSITION, position0); */
  Vsub (v, planet[0].pos, player.pos);
  f[0] = (float) v[0];
  f[1] = (float) v[1];
  f[2] = (float) v[2];
  glLightfv (GL_LIGHT0, GL_POSITION, f);

  /* Turn on lighting in general */
  glEnable (GL_LIGHTING);

  /* Turn on individual lights */
  glEnable (GL_LIGHT0);

  /* Check each non-permanent light */
  for (l=0; l<NLIGHTS; l++)
  {
    if (light[l].age > 0.0)
    {
      light[l].age += deltaT;
      glLightfv (light[l].gl_num, GL_DIFFUSE, light[l].color);
      glLightfv (light[l].gl_num, GL_SPECULAR, light[l].color);
      /*   glLightfv (light[l].gl_num, GL_POSITION, light[l].pos); */
      f[0] = light[l].pos[0] - (float) player.pos[0];
      f[1] = light[l].pos[1] - (float) player.pos[1];
      f[2] = light[l].pos[2] - (float) player.pos[2];
      glLightfv (light[l].gl_num, GL_POSITION, f);
      glEnable (light[l].gl_num);
    }
    else
    {
      /*   glDisable (light[l].gl_num); */
    }
  }

  /* Pick smooth or flat shading */
  glShadeModel (GL_SMOOTH);
  /* glShadeModel (GL_FLAT);  */
}

void InitLights()
/*
 *  Set up non-permanent light sources
 */
{
  int i;

  for (i=0; i<NLIGHTS; i++)
  {
    light[i].age = 0.0;
    light[i].pos[3] = 1.0;
    light[i].gl_num = GL_LIGHT1 + i;
  }
}

int FindLight()
/*
 *  Return free or oldest light
 */
{
  int i, oldest;
  double maxage;

  for (i=0; i<NLIGHTS; i++)
  {
    if (light[i].age == 0.0) return (i);

    if (i == 0)
    {
      oldest = i;
      maxage = light[i].age;
    }
    else
    {
      if (light[i].age > maxage)
      {
        maxage = light[i].age;
        oldest = i;
      }
    }
  }

  return (oldest);
}

void DestroyLight (int l)
/*
 *  Destroy specified light
 */
{
  light[l].age = 0.0;
  glDisable (light[l].gl_num);
}