2 // light.hxx -- lighting routines
4 // Written by Curtis Olson, started April 1998.
6 // Copyright (C) 1998 Curtis L. Olson - curt@me.umn.edu
8 // This program is free software; you can redistribute it and/or
9 // modify it under the terms of the GNU General Public License as
10 // published by the Free Software Foundation; either version 2 of the
11 // License, or (at your option) any later version.
13 // This program is distributed in the hope that it will be useful, but
14 // WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 // General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
38 #include <Debug/fg_debug.h>
39 #include <Include/fg_constants.h>
40 #include <Main/options.hxx>
41 #include <Main/views.hxx>
42 #include <Math/fg_geodesy.h>
43 #include <Math/interpolater.hxx>
44 #include <Math/mat3.h>
45 #include <Math/polar3d.hxx>
47 #include "fg_time.hxx"
52 fgLIGHT cur_light_params;
56 fgLIGHT::fgLIGHT( void ) {
60 // initialize lighting tables
61 void fgLIGHT::Init( void ) {
65 fgPrintf( FG_EVENT, FG_INFO,
66 "Initializing Lighting interpolation tables.\n" );
70 // build the path name to the ambient lookup table
72 strcat(path, o->fg_root);
73 strcat(path, "/Scenery/");
74 strcat(path, "Ambient");
75 // initialize ambient table
76 ambient_tbl = new fgINTERPTABLE(path);
78 // build the path name to the diffuse lookup table
80 strcat(path, o->fg_root);
81 strcat(path, "/Scenery/");
82 strcat(path, "Diffuse");
83 // initialize diffuse table
84 diffuse_tbl = new fgINTERPTABLE(path);
86 // build the path name to the sky lookup table
88 strcat(path, o->fg_root);
89 strcat(path, "/Scenery/");
91 // initialize sky table
92 sky_tbl = new fgINTERPTABLE(path);
96 // update lighting parameters based on current sun position
97 void fgLIGHT::Update( void ) {
100 // if the 4th field is 0.0, this specifies a direction ...
101 GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
103 GLfloat base_sky_color[4] = {0.60, 0.60, 0.90, 1.0};
105 GLfloat base_fog_color[4] = {0.90, 0.90, 1.00, 1.0};
106 double deg, ambient, diffuse, sky_brightness;
108 t = &cur_time_params;
111 fgPrintf( FG_EVENT, FG_INFO, "Updating light parameters.\n" );
113 // calculate lighting parameters based on sun's relative angle to
116 deg = sun_angle * 180.0 / FG_PI;
117 fgPrintf( FG_EVENT, FG_INFO, " Sun angle = %.2f.\n", deg );
119 ambient = ambient_tbl->interpolate( deg );
120 diffuse = diffuse_tbl->interpolate( deg );
121 sky_brightness = sky_tbl->interpolate( deg );
123 fgPrintf( FG_EVENT, FG_INFO,
124 " ambient = %.2f diffuse = %.2f sky = %.2f\n",
125 ambient, diffuse, sky_brightness );
127 // sky_brightness = 0.15; // used to force a dark sky (when testing)
129 // if ( ambient < 0.02 ) { ambient = 0.02; }
130 // if ( diffuse < 0.0 ) { diffuse = 0.0; }
131 // if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
133 scene_ambient[0] = white[0] * ambient;
134 scene_ambient[1] = white[1] * ambient;
135 scene_ambient[2] = white[2] * ambient;
137 scene_diffuse[0] = white[0] * diffuse;
138 scene_diffuse[1] = white[1] * diffuse;
139 scene_diffuse[2] = white[2] * diffuse;
142 fog_color[0] = base_fog_color[0] * sky_brightness;
143 fog_color[1] = base_fog_color[1] * sky_brightness;
144 fog_color[2] = base_fog_color[2] * sky_brightness;
145 fog_color[3] = base_fog_color[3];
148 sky_color[0] = base_sky_color[0] * sky_brightness;
149 sky_color[1] = base_sky_color[1] * sky_brightness;
150 sky_color[2] = base_sky_color[2] * sky_brightness;
151 sky_color[3] = base_sky_color[3];
156 fgLIGHT::~fgLIGHT( void ) {
160 // wrapper function for updating light parameters via the event scheduler
161 void fgLightUpdate ( void ) {
163 l = &cur_light_params;
170 // Revision 1.10 1998/07/08 14:48:38 curt
171 // polar3d.h renamed to polar3d.hxx
173 // Revision 1.9 1998/05/29 20:37:51 curt
174 // Renamed <Table>.table to be <Table> so we can add a .gz under DOS.
176 // Revision 1.8 1998/05/20 20:54:16 curt
177 // Converted fgLIGHT to a C++ class.
179 // Revision 1.7 1998/05/13 18:26:50 curt
180 // Root path info moved to fgOPTIONS.
182 // Revision 1.6 1998/05/11 18:18:51 curt
183 // Made fog color slightly bluish.
185 // Revision 1.5 1998/05/03 00:48:38 curt
186 // polar.h -> polar3d.h
188 // Revision 1.4 1998/04/28 01:22:18 curt
189 // Type-ified fgTIME and fgVIEW.
191 // Revision 1.3 1998/04/26 05:10:04 curt
192 // "struct fgLIGHT" -> "fgLIGHT" because fgLIGHT is typedef'd.
194 // Revision 1.2 1998/04/24 00:52:30 curt
195 // Wrapped "#include <config.h>" in "#ifdef HAVE_CONFIG_H"
197 // Separated out lighting calcs into their own file.
199 // Revision 1.1 1998/04/22 13:24:06 curt
200 // C++ - ifiing the code a bit.
201 // Starting to reorginize some of the lighting calcs to use a table lookup.