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.
34 #include <simgear/xgl/xgl.h>
36 #include <simgear/compiler.h>
38 #ifdef SG_MATH_EXCEPTION_CLASH
39 # define exception c_exception
42 #ifdef SG_HAVE_STD_INCLUDES
51 #include <simgear/constants.h>
52 #include <simgear/debug/logstream.hxx>
53 #include <simgear/math/interpolater.hxx>
54 #include <simgear/math/polar3d.hxx>
55 #include <simgear/misc/fgpath.hxx>
57 #include <Aircraft/aircraft.hxx>
58 #include <Main/globals.hxx>
64 fgLIGHT cur_light_params;
68 fgLIGHT::fgLIGHT( void ) {
72 // initialize lighting tables
73 void fgLIGHT::Init( void ) {
74 FG_LOG( FG_EVENT, FG_INFO,
75 "Initializing Lighting interpolation tables." );
77 // build the path name to the ambient lookup table
78 FGPath path( globals->get_fg_root() );
79 FGPath ambient = path;
80 ambient.append( "Lighting/ambient" );
81 FGPath diffuse = path;
82 diffuse.append( "Lighting/diffuse" );
84 sky.append( "Lighting/sky" );
86 // initialize ambient table
87 ambient_tbl = new SGInterpTable( ambient.str() );
89 // initialize diffuse table
90 diffuse_tbl = new SGInterpTable( diffuse.str() );
92 // initialize sky table
93 sky_tbl = new SGInterpTable( sky.str() );
97 // update lighting parameters based on current sun position
98 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 f = current_aircraft.fdm_state;
110 FG_LOG( FG_EVENT, FG_INFO, "Updating light parameters." );
112 // calculate lighting parameters based on sun's relative angle to
115 deg = sun_angle * SGD_RADIANS_TO_DEGREES;
116 FG_LOG( FG_EVENT, FG_INFO, " Sun angle = " << deg );
118 ambient = ambient_tbl->interpolate( deg );
119 diffuse = diffuse_tbl->interpolate( deg );
120 sky_brightness = sky_tbl->interpolate( deg );
122 FG_LOG( FG_EVENT, FG_INFO,
123 " ambient = " << ambient << " diffuse = " << diffuse
124 << " sky = " << sky_brightness );
126 // sky_brightness = 0.15; // used to force a dark sky (when testing)
128 // if ( ambient < 0.02 ) { ambient = 0.02; }
129 // if ( diffuse < 0.0 ) { diffuse = 0.0; }
130 // if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
132 scene_ambient[0] = white[0] * ambient;
133 scene_ambient[1] = white[1] * ambient;
134 scene_ambient[2] = white[2] * ambient;
135 scene_ambient[3] = 1.0;
137 scene_diffuse[0] = white[0] * diffuse;
138 scene_diffuse[1] = white[1] * diffuse;
139 scene_diffuse[2] = white[2] * diffuse;
140 scene_diffuse[3] = 1.0;
143 sky_color[0] = base_sky_color[0] * sky_brightness;
144 sky_color[1] = base_sky_color[1] * sky_brightness;
145 sky_color[2] = base_sky_color[2] * sky_brightness;
146 sky_color[3] = base_sky_color[3];
149 fog_color[0] = base_fog_color[0] * sky_brightness;
150 fog_color[1] = base_fog_color[1] * sky_brightness;
151 fog_color[2] = base_fog_color[2] * sky_brightness;
152 fog_color[3] = base_fog_color[3];
156 // calculate fog color adjusted for sunrise/sunset effects
157 void fgLIGHT::UpdateAdjFog( void ) {
159 double sun_angle_deg, rotation, param1[3], param2[3];
161 f = current_aircraft.fdm_state;
163 FG_LOG( FG_EVENT, FG_DEBUG, "Updating adjusted fog parameters." );
165 // set fog color (we'll try to match the sunset color in the
166 // direction we are looking
168 // first determine the difference between our view angle and local
169 // direction to the sun
170 rotation = -(sun_rotation + SGD_PI)
171 - (f->get_Psi() - globals->get_current_view()->get_view_offset());
172 if ( globals->get_current_view()->get_reverse_view_offset() ) {
175 while ( rotation < 0 ) {
178 while ( rotation > SGD_2PI ) {
181 rotation *= SGD_RADIANS_TO_DEGREES;
182 // fgPrintf( FG_EVENT, FG_INFO,
183 // " View to sun difference in degrees = %.2f\n", rotation);
185 // next check if we are in a sunset/sunrise situation
186 sun_angle_deg = sun_angle * SGD_RADIANS_TO_DEGREES;
187 if ( (sun_angle_deg > 80.0) && (sun_angle_deg < 100.0) ) {
189 param1[0] = (10.0 - fabs(90.0 - sun_angle_deg)) / 20.0;
190 param1[1] = (10.0 - fabs(90.0 - sun_angle_deg)) / 40.0;
191 param1[2] = (10.0 - fabs(90.0 - sun_angle_deg)) / 30.0;
192 // param2[2] = -(10.0 - fabs(90.0 - sun_angle)) / 30.0;
194 param1[0] = param1[1] = param1[2] = 0.0;
197 if ( rotation - 180.0 <= 0.0 ) {
198 param2[0] = param1[0] * (180.0 - rotation) / 180.0;
199 param2[1] = param1[1] * (180.0 - rotation) / 180.0;
200 param2[2] = param1[2] * (180.0 - rotation) / 180.0;
201 // printf("param1[0] = %.2f param2[0] = %.2f\n", param1[0], param2[0]);
203 param2[0] = param1[0] * (rotation - 180.0) / 180.0;
204 param2[1] = param1[1] * (rotation - 180.0) / 180.0;
205 param2[2] = param1[2] * (rotation - 180.0) / 180.0;
206 // printf("param1[0] = %.2f param2[0] = %.2f\n", param1[0], param2[0]);
209 adj_fog_color[0] = fog_color[0] + param2[0];
210 if ( adj_fog_color[0] > 1.0 ) { adj_fog_color[0] = 1.0; }
212 adj_fog_color[1] = fog_color[1] + param2[1];
213 if ( adj_fog_color[1] > 1.0 ) { adj_fog_color[1] = 1.0; }
215 adj_fog_color[2] = fog_color[2] + param2[2];
216 if ( adj_fog_color[2] > 1.0 ) { adj_fog_color[2] = 1.0; }
218 adj_fog_color[3] = fog_color[3];
223 fgLIGHT::~fgLIGHT( void ) {