2 // light.cxx -- lighting routines
4 // Written by Curtis Olson, started April 1998.
6 // Copyright (C) 1998 Curtis L. Olson - http://www.flightgear.org/~curt
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
33 #include <simgear/compiler.h>
37 #ifdef SG_MATH_EXCEPTION_CLASH
38 # define exception c_exception
41 #ifdef SG_HAVE_STD_INCLUDES
47 #include <simgear/constants.h>
48 #include <simgear/debug/logstream.hxx>
49 #include <simgear/math/interpolater.hxx>
50 #include <simgear/math/polar3d.hxx>
51 #include <simgear/misc/sg_path.hxx>
52 #include <simgear/scene/sky/sky.hxx>
53 #include <simgear/screen/colors.hxx>
55 #include <Main/main.hxx>
56 #include <Main/globals.hxx>
57 #include <Main/fg_props.hxx>
58 #include <Main/renderer.hxx>
59 #include <Main/viewer.hxx>
67 : _ambient_tbl( NULL ),
69 _specular_tbl( NULL ),
71 _prev_sun_angle(-9999.0),
87 // initialize lighting tables
88 void FGLight::init () {
89 SG_LOG( SG_EVENT, SG_INFO,
90 "Initializing Lighting interpolation tables." );
92 // build the path names of the lookup tables
93 SGPath path( globals->get_fg_root() );
95 // initialize ambient, diffuse and specular tables
96 SGPath ambient_path = path;
97 ambient_path.append( "Lighting/ambient" );
98 _ambient_tbl = new SGInterpTable( ambient_path.str() );
100 SGPath diffuse_path = path;
101 diffuse_path.append( "Lighting/diffuse" );
102 _diffuse_tbl = new SGInterpTable( diffuse_path.str() );
104 SGPath specular_path = path;
105 specular_path.append( "Lighting/specular" );
106 _specular_tbl = new SGInterpTable( specular_path.str() );
108 // initialize sky table
109 SGPath sky_path = path;
110 sky_path.append( "Lighting/sky" );
111 _sky_tbl = new SGInterpTable( sky_path.str() );
115 void FGLight::reinit () {
116 _prev_sun_angle = -9999.0;
121 delete _specular_tbl;
129 update_adj_fog_color();
132 void FGLight::bind () {
133 SGPropertyNode *prop = globals->get_props();
134 prop->tie("/sim/time/sun-angle-rad",SGRawValuePointer<double>(&_sun_angle));
135 prop->tie("/rendering/scene/ambient/red",SGRawValuePointer<float>(&_scene_ambient[0]));
136 prop->tie("/rendering/scene/ambient/green",SGRawValuePointer<float>(&_scene_ambient[1]));
137 prop->tie("/rendering/scene/ambient/blue",SGRawValuePointer<float>(&_scene_ambient[2]));
138 prop->tie("/rendering/scene/diffuse/red",SGRawValuePointer<float>(&_scene_diffuse[0]));
139 prop->tie("/rendering/scene/diffuse/green",SGRawValuePointer<float>(&_scene_diffuse[1]));
140 prop->tie("/rendering/scene/diffuse/blue",SGRawValuePointer<float>(&_scene_diffuse[2]));
141 prop->tie("/rendering/scene/specular/red",SGRawValuePointer<float>(&_scene_specular[0]));
142 prop->tie("/rendering/scene/specular/green",SGRawValuePointer<float>(&_scene_specular[1]));
143 prop->tie("/rendering/scene/specular/blue",SGRawValuePointer<float>(&_scene_specular[2]));
146 void FGLight::unbind () {
147 SGPropertyNode *prop = globals->get_props();
148 prop->untie("/sim/time/sun-angle-rad");
149 prop->untie("/rendering/scene/ambient/red");
150 prop->untie("/rendering/scene/ambient/green");
151 prop->untie("/rendering/scene/ambient/blue");
152 prop->untie("/rendering/scene/diffuse/red");
153 prop->untie("/rendering/scene/diffuse/green");
154 prop->untie("/rendering/scene/diffuse/blue");
155 prop->untie("/rendering/scene/specular/red");
156 prop->untie("/rendering/scene/specular/green");
157 prop->untie("/rendering/scene/specular/blue");
161 // update lighting parameters based on current sun position
162 void FGLight::update( double dt ) {
165 if (_dt_total >= 0.5) {
170 update_adj_fog_color();
172 if (_prev_sun_angle != _sun_angle) {
173 _prev_sun_angle = _sun_angle;
178 void FGLight::update_sky_color () {
179 // if the 4th field is 0.0, this specifies a direction ...
180 // const GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
181 const GLfloat base_sky_color[4] = { 0.31, 0.43, 0.69, 1.0 };
182 const GLfloat base_fog_color[4] = { 0.84, 0.87, 1.0, 1.0 };
184 SG_LOG( SG_EVENT, SG_DEBUG, "Updating light parameters." );
186 // calculate lighting parameters based on sun's relative angle to
189 float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
190 SG_LOG( SG_EVENT, SG_DEBUG, " Sun angle = " << deg );
192 float ambient = _ambient_tbl->interpolate( deg );
193 float diffuse = _diffuse_tbl->interpolate( deg );
194 float specular = _specular_tbl->interpolate( deg );
195 float sky_brightness = _sky_tbl->interpolate( deg );
197 SG_LOG( SG_EVENT, SG_DEBUG,
198 " ambient = " << ambient << " diffuse = " << diffuse
199 << " specular = " << specular << " sky = " << sky_brightness );
201 // sky_brightness = 0.15; // used to force a dark sky (when testing)
203 // if ( ambient < 0.02 ) { ambient = 0.02; }
204 // if ( diffuse < 0.0 ) { diffuse = 0.0; }
205 // if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
208 _sky_color[0] = base_sky_color[0] * sky_brightness;
209 _sky_color[1] = base_sky_color[1] * sky_brightness;
210 _sky_color[2] = base_sky_color[2] * sky_brightness;
211 _sky_color[3] = base_sky_color[3];
212 gamma_correct_rgb( _sky_color );
214 // set cloud and fog color
215 _cloud_color[0] = _fog_color[0] = base_fog_color[0] * sky_brightness;
216 _cloud_color[1] = _fog_color[1] = base_fog_color[1] * sky_brightness;
217 _cloud_color[2] = _fog_color[2] = base_fog_color[2] * sky_brightness;
218 _cloud_color[3] = _fog_color[3] = base_fog_color[3];
219 gamma_correct_rgb( _fog_color );
221 // adjust the cloud colors for sunrise/sunset effects (darken them)
222 if (_sun_angle > 1.0) {
223 float sun2 = sqrt(_sun_angle);
224 _cloud_color[0] /= sun2;
225 _cloud_color[1] /= sun2;
226 _cloud_color[2] /= sun2;
228 gamma_correct_rgb( _cloud_color );
230 float *sun_color = thesky->get_sun_color();
232 _scene_ambient[0] = ((sun_color[0]*0.25 + _cloud_color[0]*0.75) + ambient) / 2;
233 _scene_ambient[1] = ((sun_color[1]*0.25 + _cloud_color[1]*0.75) + ambient) / 2;
234 _scene_ambient[2] = ((sun_color[2]*0.25 + _cloud_color[2]*0.75) + ambient) / 2;
235 _scene_ambient[3] = 1.0;
237 _scene_diffuse[0] = (sun_color[0]*0.25 + _fog_color[0]*0.75) * diffuse;
238 _scene_diffuse[1] = (sun_color[1]*0.25 + _fog_color[1]*0.75) * diffuse;
239 _scene_diffuse[2] = (sun_color[2]*0.25 + _fog_color[2]*0.75) * diffuse;
240 _scene_diffuse[3] = 1.0;
242 _scene_specular[0] = sun_color[0] * specular;
243 _scene_specular[1] = sun_color[1] * specular;
244 _scene_specular[2] = sun_color[2] * specular;
245 _scene_specular[3] = 1.0;
249 // calculate fog color adjusted for sunrise/sunset effects
250 void FGLight::update_adj_fog_color () {
252 double heading = globals->get_current_view()->getHeading_deg()
253 * SGD_DEGREES_TO_RADIANS;
254 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
255 * SGD_DEGREES_TO_RADIANS;
257 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
259 // set fog color (we'll try to match the sunset color in the
260 // direction we are looking
262 // Do some sanity checking ...
263 if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
264 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
268 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
269 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
273 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
274 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
280 // first determine the difference between our view angle and local
281 // direction to the sun
282 rotation = -(_sun_rotation + SGD_PI) - heading + heading_offset;
283 while ( rotation < 0 ) {
286 while ( rotation > SGD_2PI ) {
290 // revert to unmodified values before usign them.
292 float *sun_color = thesky->get_sun_color();
294 gamma_restore_rgb( _fog_color );
296 // Calculate the fog color in the direction of the sun for
297 // sunrise/sunset effects.
299 float s_red = (_fog_color[0] + 2 * sun_color[0]*sun_color[0]) / 3;
300 float s_green = (_fog_color[1] + 2 * sun_color[1]*sun_color[1]) / 3;
301 float s_blue = (_fog_color[2] + 2 * sun_color[2]) / 3;
303 // interpolate beween the sunrise/sunset color and the color
304 // at the opposite direction of this effect. Take in account
305 // the current visibility.
307 float av = thesky->get_visibility();
311 float avf = 0.87 - (45000 - av) / 83333.33;
312 float sif = 0.5 - cos(_sun_angle*2)/2;
317 float rf1 = fabs((rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
318 float rf2 = avf * pow(rf1 * rf1, 1/sif);
319 float rf3 = 0.94 - rf2;
321 _adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
322 _adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
323 _adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
324 gamma_correct_rgb( _adj_fog_color );
326 // make sure the colors have their original value before they are being
327 // used by the rest of the program.
329 gamma_correct_rgb( _fog_color );