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>
56 #include <Aircraft/aircraft.hxx>
57 #include <Main/globals.hxx>
58 #include <Main/viewer.hxx>
64 fgLIGHT cur_light_params;
68 fgLIGHT::fgLIGHT( void ) {
72 // initialize lighting tables
73 void fgLIGHT::Init( void ) {
74 SG_LOG( SG_EVENT, SG_INFO,
75 "Initializing Lighting interpolation tables." );
77 // build the path name to the ambient lookup table
78 SGPath path( globals->get_fg_root() );
79 SGPath ambient = path;
80 ambient.append( "Lighting/ambient" );
81 SGPath diffuse = path;
82 diffuse.append( "Lighting/diffuse" );
83 SGPath specular = path;
84 specular.append( "Lighting/specular" );
86 sky.append( "Lighting/sky" );
88 // initialize ambient table
89 ambient_tbl = new SGInterpTable( ambient.str() );
91 // initialize diffuse table
92 diffuse_tbl = new SGInterpTable( diffuse.str() );
94 // initialize diffuse table
95 specular_tbl = new SGInterpTable( specular.str() );
97 // initialize sky table
98 sky_tbl = new SGInterpTable( sky.str() );
102 // update lighting parameters based on current sun position
103 void fgLIGHT::Update( void ) {
105 // if the 4th field is 0.0, this specifies a direction ...
106 GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
109 GLfloat base_sky_color[4] = { 0.20, 0.32, 0.50, 1.0 };
111 GLfloat base_sky_color[4] = { 0.38, 0.57, 0.82, 1.0 };
114 GLfloat base_fog_color[4] = { 0.65, 0.62, 0.70, 1.0 };
115 double deg, ambient, diffuse, specular, sky_brightness;
117 f = current_aircraft.fdm_state;
119 SG_LOG( SG_EVENT, SG_INFO, "Updating light parameters." );
121 // calculate lighting parameters based on sun's relative angle to
124 deg = sun_angle * SGD_RADIANS_TO_DEGREES;
125 SG_LOG( SG_EVENT, SG_INFO, " Sun angle = " << deg );
127 ambient = ambient_tbl->interpolate( deg );
128 diffuse = diffuse_tbl->interpolate( deg );
129 specular = specular_tbl->interpolate( deg );
130 sky_brightness = sky_tbl->interpolate( deg );
132 SG_LOG( SG_EVENT, SG_INFO,
133 " ambient = " << ambient << " diffuse = " << diffuse
134 << " specular = " << specular << " sky = " << sky_brightness );
136 // sky_brightness = 0.15; // used to force a dark sky (when testing)
138 // if ( ambient < 0.02 ) { ambient = 0.02; }
139 // if ( diffuse < 0.0 ) { diffuse = 0.0; }
140 // if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
142 scene_ambient[0] = white[0] * ambient;
143 scene_ambient[1] = white[1] * ambient;
144 scene_ambient[2] = white[2] * ambient;
145 scene_ambient[3] = 1.0;
147 scene_diffuse[0] = white[0] * diffuse;
148 scene_diffuse[1] = white[1] * diffuse;
149 scene_diffuse[2] = white[2] * diffuse;
150 scene_diffuse[3] = 1.0;
152 scene_specular[0] = white[0] * specular;
153 scene_specular[1] = white[1] * specular;
154 scene_specular[2] = white[2] * specular;
155 scene_specular[3] = 1.0;
158 sky_color[0] = base_sky_color[0] * sky_brightness;
159 sky_color[1] = base_sky_color[1] * sky_brightness;
160 sky_color[2] = base_sky_color[2] * sky_brightness;
161 sky_color[3] = base_sky_color[3];
164 fog_color[0] = base_fog_color[0] * sky_brightness;
165 fog_color[1] = base_fog_color[1] * sky_brightness;
166 fog_color[2] = base_fog_color[2] * sky_brightness;
167 fog_color[3] = base_fog_color[3];
171 // calculate fog color adjusted for sunrise/sunset effects
172 void fgLIGHT::UpdateAdjFog( void ) {
174 double sun_angle_deg, rotation, param1[3], param2[3];
176 f = current_aircraft.fdm_state;
178 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
180 // set fog color (we'll try to match the sunset color in the
181 // direction we are looking
183 // Do some sanity checking ...
184 if ( sun_rotation < -2.0 * SGD_2PI || sun_rotation > 2.0 * SGD_2PI ) {
185 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << sun_rotation );
188 if ( f->get_Psi() < -2.0 * SGD_2PI || f->get_Psi() > 2.0 * SGD_2PI ) {
189 SG_LOG( SG_EVENT, SG_ALERT, "Psi rotation bad = " << f->get_Psi() );
192 if ( globals->get_current_view()->getHeadingOffset_deg() * SGD_DEGREES_TO_RADIANS < -2.0 * SGD_2PI ||
193 globals->get_current_view()->getHeadingOffset_deg() * SGD_DEGREES_TO_RADIANS > 2.0 * SGD_2PI ) {
194 SG_LOG( SG_EVENT, SG_ALERT, "current view()->view offset bad = "
195 << globals->get_current_view()->getHeadingOffset_deg() * SGD_DEGREES_TO_RADIANS );
199 // first determine the difference between our view angle and local
200 // direction to the sun
201 rotation = -(sun_rotation + SGD_PI)
202 - (f->get_Psi() - globals->get_current_view()->getHeadingOffset_deg() * SGD_DEGREES_TO_RADIANS);
203 while ( rotation < 0 ) {
206 while ( rotation > SGD_2PI ) {
209 rotation *= SGD_RADIANS_TO_DEGREES;
210 // fgPrintf( SG_EVENT, SG_INFO,
211 // " View to sun difference in degrees = %.2f\n", rotation);
213 // next check if we are in a sunset/sunrise situation
214 sun_angle_deg = sun_angle * SGD_RADIANS_TO_DEGREES;
215 if ( (sun_angle_deg > 80.0) && (sun_angle_deg < 100.0) ) {
217 param1[0] = (10.0 - fabs(90.0 - sun_angle_deg)) / 20.0;
218 param1[1] = (10.0 - fabs(90.0 - sun_angle_deg)) / 40.0;
219 param1[2] = (10.0 - fabs(90.0 - sun_angle_deg)) / 30.0;
220 // param2[2] = -(10.0 - fabs(90.0 - sun_angle)) / 30.0;
222 param1[0] = param1[1] = param1[2] = 0.0;
225 if ( rotation - 180.0 <= 0.0 ) {
226 param2[0] = param1[0] * (180.0 - rotation) / 180.0;
227 param2[1] = param1[1] * (180.0 - rotation) / 180.0;
228 param2[2] = param1[2] * (180.0 - rotation) / 180.0;
229 // printf("param1[0] = %.2f param2[0] = %.2f\n", param1[0], param2[0]);
231 param2[0] = param1[0] * (rotation - 180.0) / 180.0;
232 param2[1] = param1[1] * (rotation - 180.0) / 180.0;
233 param2[2] = param1[2] * (rotation - 180.0) / 180.0;
234 // printf("param1[0] = %.2f param2[0] = %.2f\n", param1[0], param2[0]);
237 adj_fog_color[0] = fog_color[0] + param2[0];
238 if ( adj_fog_color[0] > 1.0 ) { adj_fog_color[0] = 1.0; }
240 adj_fog_color[1] = fog_color[1] + param2[1];
241 if ( adj_fog_color[1] > 1.0 ) { adj_fog_color[1] = 1.0; }
243 adj_fog_color[2] = fog_color[2] + param2[2];
244 if ( adj_fog_color[2] > 1.0 ) { adj_fog_color[2] = 1.0; }
246 adj_fog_color[3] = fog_color[3];
251 fgLIGHT::~fgLIGHT( void ) {