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.
35 #include <simgear/compiler.h>
37 #ifdef SG_MATH_EXCEPTION_CLASH
38 # define exception c_exception
41 #ifdef SG_HAVE_STD_INCLUDES
50 #include <simgear/constants.h>
51 #include <simgear/debug/logstream.hxx>
52 #include <simgear/math/interpolater.hxx>
53 #include <simgear/math/polar3d.hxx>
54 #include <simgear/misc/sg_path.hxx>
55 #include <simgear/sky/sky.hxx>
57 #include <Aircraft/aircraft.hxx>
58 #include <Main/globals.hxx>
59 #include <Main/viewer.hxx>
64 extern SGSky *thesky; // FIXME: from main.cxx
66 fgLIGHT cur_light_params;
70 fgLIGHT::fgLIGHT( void ) {
74 // initialize lighting tables
75 void fgLIGHT::Init( void ) {
76 SG_LOG( SG_EVENT, SG_INFO,
77 "Initializing Lighting interpolation tables." );
79 // build the path name to the ambient lookup table
80 SGPath path( globals->get_fg_root() );
81 SGPath ambient = path;
82 ambient.append( "Lighting/ambient" );
83 SGPath diffuse = path;
84 diffuse.append( "Lighting/diffuse" );
85 SGPath specular = path;
86 specular.append( "Lighting/specular" );
88 sky.append( "Lighting/sky" );
90 // initialize ambient table
91 ambient_tbl = new SGInterpTable( ambient.str() );
93 // initialize diffuse table
94 diffuse_tbl = new SGInterpTable( diffuse.str() );
96 // initialize diffuse table
97 specular_tbl = new SGInterpTable( specular.str() );
99 // initialize sky table
100 sky_tbl = new SGInterpTable( sky.str() );
104 // update lighting parameters based on current sun position
105 void fgLIGHT::Update( void ) {
107 // if the 4th field is 0.0, this specifies a direction ...
108 GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
110 #if defined (sgi) || defined( macintosh )
111 GLfloat base_sky_color[4] = { 0.252, 0.403, 0.657, 1.0 };
113 GLfloat base_sky_color[4] = { 0.336, 0.406, 0.574, 1.0 };
115 GLfloat base_fog_color[4] = { 0.80, 0.83, 1.0, 1.0 };
116 double deg, ambient, diffuse, specular, sky_brightness;
118 f = current_aircraft.fdm_state;
120 SG_LOG( SG_EVENT, SG_INFO, "Updating light parameters." );
122 // calculate lighting parameters based on sun's relative angle to
126 float *sun_color = thesky->get_sun_color();
128 base_fog_color[0] *= (1.25 - sun_color[0]/4.0); // 100% red
129 base_fog_color[1] *= (0.48 + sun_color[1]/1.923); // 40% green
130 base_fog_color[2] *= sun_color[2]; // 0% blue
133 deg = sun_angle * SGD_RADIANS_TO_DEGREES;
134 SG_LOG( SG_EVENT, SG_INFO, " Sun angle = " << deg );
136 ambient = ambient_tbl->interpolate( deg );
137 diffuse = diffuse_tbl->interpolate( deg );
138 specular = specular_tbl->interpolate( deg );
139 sky_brightness = sky_tbl->interpolate( deg );
141 SG_LOG( SG_EVENT, SG_INFO,
142 " ambient = " << ambient << " diffuse = " << diffuse
143 << " specular = " << specular << " sky = " << sky_brightness );
145 // sky_brightness = 0.15; // used to force a dark sky (when testing)
147 // if ( ambient < 0.02 ) { ambient = 0.02; }
148 // if ( diffuse < 0.0 ) { diffuse = 0.0; }
149 // if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
151 scene_ambient[0] = white[0] * ambient;
152 scene_ambient[1] = white[1] * ambient;
153 scene_ambient[2] = white[2] * ambient;
154 scene_ambient[3] = 1.0;
156 scene_diffuse[0] = white[0] * diffuse;
157 scene_diffuse[1] = white[1] * diffuse;
158 scene_diffuse[2] = white[2] * diffuse;
159 scene_diffuse[3] = 1.0;
161 scene_specular[0] = white[0] * specular;
162 scene_specular[1] = white[1] * specular;
163 scene_specular[2] = white[2] * specular;
164 scene_specular[3] = 1.0;
167 sky_color[0] = base_sky_color[0] * sky_brightness;
168 sky_color[1] = base_sky_color[1] * sky_brightness;
169 sky_color[2] = base_sky_color[2] * sky_brightness;
170 sky_color[3] = base_sky_color[3];
173 fog_color[0] = base_fog_color[0] * sky_brightness;
174 fog_color[1] = base_fog_color[1] * sky_brightness;
175 fog_color[2] = base_fog_color[2] * sky_brightness;
176 fog_color[3] = base_fog_color[3];
180 // calculate fog color adjusted for sunrise/sunset effects
181 void fgLIGHT::UpdateAdjFog( void ) {
183 double sun_angle_deg, rotation, param1[3], param2[3];
185 f = current_aircraft.fdm_state;
187 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
189 // set fog color (we'll try to match the sunset color in the
190 // direction we are looking
192 // Do some sanity checking ...
193 if ( sun_rotation < -2.0 * SGD_2PI || sun_rotation > 2.0 * SGD_2PI ) {
194 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << sun_rotation );
197 if ( f->get_Psi() < -2.0 * SGD_2PI || f->get_Psi() > 2.0 * SGD_2PI ) {
198 SG_LOG( SG_EVENT, SG_ALERT, "Psi rotation bad = " << f->get_Psi() );
201 if ( globals->get_current_view()->getHeadingOffset_deg() * SGD_DEGREES_TO_RADIANS < -2.0 * SGD_2PI ||
202 globals->get_current_view()->getHeadingOffset_deg() * SGD_DEGREES_TO_RADIANS > 2.0 * SGD_2PI ) {
203 SG_LOG( SG_EVENT, SG_ALERT, "current view()->view offset bad = "
204 << globals->get_current_view()->getHeadingOffset_deg() * SGD_DEGREES_TO_RADIANS );
208 // first determine the difference between our view angle and local
209 // direction to the sun
210 rotation = -(sun_rotation + SGD_PI)
211 - (f->get_Psi() - globals->get_current_view()->getHeadingOffset_deg() * SGD_DEGREES_TO_RADIANS);
212 while ( rotation < 0 ) {
215 while ( rotation > SGD_2PI ) {
218 rotation *= SGD_RADIANS_TO_DEGREES;
219 // fgPrintf( SG_EVENT, SG_INFO,
220 // " View to sun difference in degrees = %.2f\n", rotation);
222 // next check if we are in a sunset/sunrise situation
223 sun_angle_deg = sun_angle * SGD_RADIANS_TO_DEGREES;
224 if ( (sun_angle_deg > 80.0) && (sun_angle_deg < 100.0) ) {
226 param1[0] = (10.0 - fabs(90.0 - sun_angle_deg)) / 20.0;
227 param1[1] = (10.0 - fabs(90.0 - sun_angle_deg)) / 40.0;
228 param1[2] = (10.0 - fabs(90.0 - sun_angle_deg)) / 30.0;
229 // param2[2] = -(10.0 - fabs(90.0 - sun_angle)) / 30.0;
231 param1[0] = param1[1] = param1[2] = 0.0;
234 if ( rotation - 180.0 <= 0.0 ) {
235 param2[0] = param1[0] * (180.0 - rotation) / 180.0;
236 param2[1] = param1[1] * (180.0 - rotation) / 180.0;
237 param2[2] = param1[2] * (180.0 - rotation) / 180.0;
238 // printf("param1[0] = %.2f param2[0] = %.2f\n", param1[0], param2[0]);
240 param2[0] = param1[0] * (rotation - 180.0) / 180.0;
241 param2[1] = param1[1] * (rotation - 180.0) / 180.0;
242 param2[2] = param1[2] * (rotation - 180.0) / 180.0;
243 // printf("param1[0] = %.2f param2[0] = %.2f\n", param1[0], param2[0]);
246 adj_fog_color[0] = fog_color[0] + param2[0];
247 if ( adj_fog_color[0] > 1.0 ) { adj_fog_color[0] = 1.0; }
249 adj_fog_color[1] = fog_color[1] + param2[1];
250 if ( adj_fog_color[1] > 1.0 ) { adj_fog_color[1] = 1.0; }
252 adj_fog_color[2] = fog_color[2] + param2[2];
253 if ( adj_fog_color[2] > 1.0 ) { adj_fog_color[2] = 1.0; }
255 adj_fog_color[3] = fog_color[3];
260 fgLIGHT::~fgLIGHT( void ) {