2 // light.cxx -- 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/scene/sky/sky.hxx>
56 #include <simgear/screen/colors.hxx>
58 #include <Main/globals.hxx>
59 #include <Main/fg_props.hxx>
60 #include <Main/viewer.hxx>
65 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 ) {
106 // if the 4th field is 0.0, this specifies a direction ...
107 GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
109 GLfloat base_sky_color[4] = { 0.39, 0.50, 0.74, 1.0 };
111 GLfloat base_fog_color[4] = { 0.84, 0.87, 1.0, 1.0 };
112 float deg, ambient, diffuse, specular, sky_brightness;
114 SG_LOG( SG_EVENT, SG_INFO, "Updating light parameters." );
116 // calculate lighting parameters based on sun's relative angle to
119 deg = sun_angle * SGD_RADIANS_TO_DEGREES;
120 SG_LOG( SG_EVENT, SG_INFO, " Sun angle = " << deg );
122 ambient = ambient_tbl->interpolate( deg );
123 diffuse = diffuse_tbl->interpolate( deg );
124 specular = specular_tbl->interpolate( deg );
125 sky_brightness = sky_tbl->interpolate( deg );
127 SG_LOG( SG_EVENT, SG_INFO,
128 " ambient = " << ambient << " diffuse = " << diffuse
129 << " specular = " << specular << " sky = " << sky_brightness );
131 // sky_brightness = 0.15; // used to force a dark sky (when testing)
133 // if ( ambient < 0.02 ) { ambient = 0.02; }
134 // if ( diffuse < 0.0 ) { diffuse = 0.0; }
135 // if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
138 sky_color[0] = base_sky_color[0] * sky_brightness;
139 sky_color[1] = base_sky_color[1] * sky_brightness;
140 sky_color[2] = base_sky_color[2] * sky_brightness;
141 sky_color[3] = base_sky_color[3];
142 gamma_correct_rgb( sky_color );
144 // set cloud and fog color
145 cloud_color[0] = fog_color[0] = base_fog_color[0] * sky_brightness;
146 cloud_color[1] = fog_color[1] = base_fog_color[1] * sky_brightness;
147 cloud_color[2] = fog_color[2] = base_fog_color[2] * sky_brightness;
148 cloud_color[3] = fog_color[3] = base_fog_color[3];
149 gamma_correct_rgb( fog_color );
151 // adjust the cloud colors for sunrise/sunset effects (darken them)
152 if (sun_angle > 1.0) {
153 float sun2 = sqrt(sun_angle);
154 cloud_color[0] /= sun2;
155 cloud_color[1] /= sun2;
156 cloud_color[2] /= sun2;
158 gamma_correct_rgb( cloud_color );
160 if (fgGetBool("/test/scene_lighting")) {
161 float *sun_color = thesky->get_sun_color();
163 scene_ambient[0] = (sun_color[0]*0.1 + cloud_color[0]*0.9) * ambient;
164 scene_ambient[1] = (sun_color[1]*0.1 + cloud_color[1]*0.9) * ambient;
165 scene_ambient[2] = (sun_color[2]*0.1 + cloud_color[2]*0.9) * ambient;
166 scene_ambient[3] = 1.5;
168 scene_diffuse[0] = (sun_color[0]*0.25 + fog_color[0]*0.75) * diffuse;
169 scene_diffuse[1] = (sun_color[1]*0.25 + fog_color[1]*0.75) * diffuse;
170 scene_diffuse[2] = (sun_color[2]*0.25 + fog_color[2]*0.75) * diffuse;
171 scene_diffuse[3] = 1.5;
173 scene_specular[0] = sun_color[0] * specular;
174 scene_specular[1] = sun_color[1] * specular;
175 scene_specular[2] = sun_color[2] * specular;
176 scene_specular[3] = 1.0;
180 scene_ambient[0] = white[0] * ambient;
181 scene_ambient[1] = white[1] * ambient;
182 scene_ambient[2] = white[2] * ambient;
183 scene_ambient[3] = 1.0;
185 scene_diffuse[0] = white[0] * diffuse;
186 scene_diffuse[1] = white[1] * diffuse;
187 scene_diffuse[2] = white[2] * diffuse;
188 scene_diffuse[3] = 1.0;
190 scene_specular[0] = white[0] * ambient;
191 scene_specular[1] = white[1] * ambient;
192 scene_specular[2] = white[2] * ambient;
193 scene_specular[3] = 1.0;
198 // calculate fog color adjusted for sunrise/sunset effects
199 void fgLIGHT::UpdateAdjFog( void ) {
201 double heading = globals->get_current_view()->getHeading_deg()
202 * SGD_DEGREES_TO_RADIANS;
203 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
204 * SGD_DEGREES_TO_RADIANS;
206 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
208 // set fog color (we'll try to match the sunset color in the
209 // direction we are looking
211 // Do some sanity checking ...
212 if ( sun_rotation < -2.0 * SGD_2PI || sun_rotation > 2.0 * SGD_2PI ) {
213 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << sun_rotation );
217 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
218 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
222 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
223 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
229 // first determine the difference between our view angle and local
230 // direction to the sun
231 rotation = -(sun_rotation + SGD_PI) - heading + heading_offset;
232 while ( rotation < 0 ) {
235 while ( rotation > SGD_2PI ) {
239 // revert to unmodified values before usign them.
241 float *sun_color = thesky->get_sun_color();
243 gamma_restore_rgb( fog_color );
244 gamma_restore_rgb( cloud_color );
246 // Calculate the fog color in the direction of the sun for
247 // sunrise/sunset effects.
249 float s_red = (fog_color[0] + 2 * sun_color[0]*sun_color[0]) / 3;
250 float s_green = (fog_color[1] + 2 * sun_color[1]*sun_color[1]) / 3;
251 float s_blue = (fog_color[2] + 2 * sun_color[2]) / 3;
253 // interpolate beween the sunrise/sunset color and the color
254 // at the opposite direction of this effect. Take in account
255 // the current visibility.
257 float av = thesky->get_visibility();
261 float avf = 0.87 - (45000 - av) / 83333.33;
262 float sif = 0.5 - cos(sun_angle*2)/2;
264 float rf1 = fabs((rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
265 float rf2 = avf * pow(rf1 * rf1, 1/sif);
266 float rf3 = 0.94 - rf2;
268 adj_fog_color[0] = rf3 * fog_color[0] + rf2 * s_red;
269 adj_fog_color[1] = rf3 * fog_color[1] + rf2 * s_green;
270 adj_fog_color[2] = rf3 * fog_color[2] + rf2 * s_blue;
271 gamma_correct_rgb( adj_fog_color );
273 // make sure the colors have their original value before they are being
274 // used by the rest of the program.
276 gamma_correct_rgb( fog_color );
277 gamma_correct_rgb( cloud_color );
282 fgLIGHT::~fgLIGHT( void ) {