1
0
Fork 0
flightgear/Time/light.cxx
1998-04-28 01:22:16 +00:00

176 lines
5.1 KiB
C++

//
// light.hxx -- lighting routines
//
// Written by Curtis Olson, started April 1998.
//
// Copyright (C) 1998 Curtis L. Olson - curt@me.umn.edu
//
// 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., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#ifdef HAVE_WINDOWS_H
# include <windows.h>
#endif
#include <GL/glut.h>
#include <XGL/xgl.h>
#include <string.h>
#include <Debug/fg_debug.h>
#include <Include/fg_constants.h>
#include <Include/general.h>
#include <Main/views.hxx>
#include <Math/fg_geodesy.h>
#include <Math/interpolater.hxx>
#include <Math/mat3.h>
#include <Math/polar.h>
#include "fg_time.hxx"
#include "light.hxx"
#include "sunpos.hxx"
fgLIGHT cur_light_params;
static fgINTERPTABLE *ambient_tbl;
static fgINTERPTABLE *diffuse_tbl;
static fgINTERPTABLE *sky_tbl;
// initialize lighting tables
void fgLightInit( void ) {
fgGENERAL *g;
char path[256];
fgPrintf( FG_EVENT, FG_INFO,
"Initializing Lighting interpolation tables.\n" );
g = &general;
// build the path name to the ambient lookup table
path[0] = '\0';
strcat(path, g->root_dir);
strcat(path, "/Scenery/");
strcat(path, "Ambient.table");
// initialize ambient table
ambient_tbl = new fgINTERPTABLE(path);
// build the path name to the diffuse lookup table
path[0] = '\0';
strcat(path, g->root_dir);
strcat(path, "/Scenery/");
strcat(path, "Diffuse.table");
// initialize diffuse table
diffuse_tbl = new fgINTERPTABLE(path);
// build the path name to the sky lookup table
path[0] = '\0';
strcat(path, g->root_dir);
strcat(path, "/Scenery/");
strcat(path, "Sky.table");
// initialize sky table
sky_tbl = new fgINTERPTABLE(path);
}
// update lighting parameters based on current sun position
void fgLightUpdate( void ) {
fgLIGHT *l;
fgTIME *t;
fgVIEW *v;
/* if the 4th field is 0.0, this specifies a direction ... */
GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
/* base sky color */
GLfloat base_sky_color[4] = {0.60, 0.60, 0.90, 1.0};
/* base fog color */
GLfloat base_fog_color[4] = {1.00, 1.00, 1.00, 1.0};
double deg, ambient, diffuse, sky_brightness;
l = &cur_light_params;
t = &cur_time_params;
v = &current_view;
fgPrintf( FG_EVENT, FG_INFO, "Updating light parameters.\n" );
/* calculate lighting parameters based on sun's relative angle to
* local up */
deg = l->sun_angle * 180.0 / FG_PI;
fgPrintf( FG_EVENT, FG_INFO, " Sun angle = %.2f.\n", deg );
ambient = ambient_tbl->interpolate( deg );
diffuse = diffuse_tbl->interpolate( deg );
sky_brightness = sky_tbl->interpolate( deg );
fgPrintf( FG_EVENT, FG_INFO,
" ambient = %.2f diffuse = %.2f sky = %.2f\n",
ambient, diffuse, sky_brightness );
// sky_brightness = 0.15; // used to force a dark sky (when testing)
// if ( ambient < 0.02 ) { ambient = 0.02; }
// if ( diffuse < 0.0 ) { diffuse = 0.0; }
// if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
l->scene_ambient[0] = white[0] * ambient;
l->scene_ambient[1] = white[1] * ambient;
l->scene_ambient[2] = white[2] * ambient;
l->scene_diffuse[0] = white[0] * diffuse;
l->scene_diffuse[1] = white[1] * diffuse;
l->scene_diffuse[2] = white[2] * diffuse;
/* set fog color */
// l->fog_color[0] = base_fog_color[0] * (ambient + diffuse);
// l->fog_color[1] = base_fog_color[1] * (ambient + diffuse);
// l->fog_color[2] = base_fog_color[2] * (ambient + diffuse);
// l->fog_color[3] = base_fog_color[3];
l->fog_color[0] = base_fog_color[0] * sky_brightness;
l->fog_color[1] = base_fog_color[1] * sky_brightness;
l->fog_color[2] = base_fog_color[2] * sky_brightness;
l->fog_color[3] = base_fog_color[3];
/* set sky color */
l->sky_color[0] = base_sky_color[0] * sky_brightness;
l->sky_color[1] = base_sky_color[1] * sky_brightness;
l->sky_color[2] = base_sky_color[2] * sky_brightness;
l->sky_color[3] = base_sky_color[3];
}
// $Log$
// Revision 1.4 1998/04/28 01:22:18 curt
// Type-ified fgTIME and fgVIEW.
//
// Revision 1.3 1998/04/26 05:10:04 curt
// "struct fgLIGHT" -> "fgLIGHT" because fgLIGHT is typedef'd.
//
// Revision 1.2 1998/04/24 00:52:30 curt
// Wrapped "#include <config.h>" in "#ifdef HAVE_CONFIG_H"
// Fog color fixes.
// Separated out lighting calcs into their own file.
//
// Revision 1.1 1998/04/22 13:24:06 curt
// C++ - ifiing the code a bit.
// Starting to reorginize some of the lighting calcs to use a table lookup.
//
//