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.
29 #include <simgear/compiler.h>
33 #include <simgear/constants.h>
34 #include <simgear/debug/logstream.hxx>
35 #include <simgear/math/interpolater.hxx>
36 #include <simgear/misc/sg_path.hxx>
37 #include <simgear/scene/sky/sky.hxx>
38 #include <simgear/screen/colors.hxx>
40 #include <Main/main.hxx>
41 #include <Main/globals.hxx>
42 #include <Main/fg_props.hxx>
43 #include <Main/renderer.hxx>
44 #include <Main/viewer.hxx>
52 : _ambient_tbl( NULL ),
54 _specular_tbl( NULL ),
61 _moon_vec(0, 0, 0, 0),
62 _sun_vec_inv(0, 0, 0, 0),
63 _moon_vec_inv(0, 0, 0, 0),
69 _scene_ambient(0, 0, 0, 0),
70 _scene_diffuse(0, 0, 0, 0),
71 _scene_specular(0, 0, 0, 0),
72 _sky_color(0, 0, 0, 0),
73 _fog_color(0, 0, 0, 0),
74 _cloud_color(0, 0, 0, 0),
75 _adj_fog_color(0, 0, 0, 0),
76 _adj_sky_color(0, 0, 0, 0),
91 // initialize lighting tables
92 void FGLight::init () {
93 SG_LOG( SG_EVENT, SG_INFO,
94 "Initializing Lighting interpolation tables." );
96 // build the path names of the lookup tables
97 SGPath path( globals->get_fg_root() );
99 // initialize ambient, diffuse and specular tables
100 SGPath ambient_path = path;
101 ambient_path.append( "Lighting/ambient" );
102 _ambient_tbl = new SGInterpTable( ambient_path.str() );
104 SGPath diffuse_path = path;
105 diffuse_path.append( "Lighting/diffuse" );
106 _diffuse_tbl = new SGInterpTable( diffuse_path.str() );
108 SGPath specular_path = path;
109 specular_path.append( "Lighting/specular" );
110 _specular_tbl = new SGInterpTable( specular_path.str() );
112 // initialize sky table
113 SGPath sky_path = path;
114 sky_path.append( "Lighting/sky" );
115 _sky_tbl = new SGInterpTable( sky_path.str() );
119 void FGLight::reinit () {
120 _prev_sun_angle = -9999.0;
125 delete _specular_tbl;
133 update_adj_fog_color();
136 void FGLight::bind () {
137 SGPropertyNode *prop = globals->get_props();
138 prop->tie("/sim/time/sun-angle-rad",SGRawValuePointer<double>(&_sun_angle));
139 prop->tie("/rendering/scene/ambient/red",SGRawValuePointer<float>(&_scene_ambient[0]));
140 prop->tie("/rendering/scene/ambient/green",SGRawValuePointer<float>(&_scene_ambient[1]));
141 prop->tie("/rendering/scene/ambient/blue",SGRawValuePointer<float>(&_scene_ambient[2]));
142 prop->tie("/rendering/scene/diffuse/red",SGRawValuePointer<float>(&_scene_diffuse[0]));
143 prop->tie("/rendering/scene/diffuse/green",SGRawValuePointer<float>(&_scene_diffuse[1]));
144 prop->tie("/rendering/scene/diffuse/blue",SGRawValuePointer<float>(&_scene_diffuse[2]));
145 prop->tie("/rendering/scene/specular/red",SGRawValuePointer<float>(&_scene_specular[0]));
146 prop->tie("/rendering/scene/specular/green",SGRawValuePointer<float>(&_scene_specular[1]));
147 prop->tie("/rendering/scene/specular/blue",SGRawValuePointer<float>(&_scene_specular[2]));
148 prop->tie("/rendering/dome/sky/red",SGRawValuePointer<float>(&_sky_color[0]));
149 prop->tie("/rendering/dome/sky/green",SGRawValuePointer<float>(&_sky_color[1]));
150 prop->tie("/rendering/dome/sky/blue",SGRawValuePointer<float>(&_sky_color[2]));
151 prop->tie("/rendering/dome/fog/red",SGRawValuePointer<float>(&_fog_color[0]));
152 prop->tie("/rendering/dome/fog/green",SGRawValuePointer<float>(&_fog_color[1]));
153 prop->tie("/rendering/dome/fog/blue",SGRawValuePointer<float>(&_fog_color[2]));
156 void FGLight::unbind () {
157 SGPropertyNode *prop = globals->get_props();
158 prop->untie("/sim/time/sun-angle-rad");
159 prop->untie("/rendering/scene/ambient/red");
160 prop->untie("/rendering/scene/ambient/green");
161 prop->untie("/rendering/scene/ambient/blue");
162 prop->untie("/rendering/scene/diffuse/red");
163 prop->untie("/rendering/scene/diffuse/green");
164 prop->untie("/rendering/scene/diffuse/blue");
165 prop->untie("/rendering/scene/specular/red");
166 prop->untie("/rendering/scene/specular/green");
167 prop->untie("/rendering/scene/specular/blue");
168 prop->untie("/rendering/dome/sun/red");
169 prop->untie("/rendering/dome/sun/green");
170 prop->untie("/rendering/dome/sun/blue");
171 prop->untie("/rendering/dome/sky/red");
172 prop->untie("/rendering/dome/sky/green");
173 prop->untie("/rendering/dome/sky/blue");
174 prop->untie("/rendering/dome/fog/red");
175 prop->untie("/rendering/dome/fog/green");
176 prop->untie("/rendering/dome/fog/blue");
180 // update lighting parameters based on current sun position
181 void FGLight::update( double dt ) {
184 if (_dt_total >= 0.5) {
189 update_adj_fog_color();
191 if (_prev_sun_angle != _sun_angle) {
192 _prev_sun_angle = _sun_angle;
197 void FGLight::update_sky_color () {
198 // if the 4th field is 0.0, this specifies a direction ...
199 // const GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
200 const GLfloat base_sky_color[4] = { 0.31, 0.43, 0.69, 1.0 };
201 const GLfloat base_fog_color[4] = { 0.60, 0.70, 0.9, 1.0 };
203 SG_LOG( SG_EVENT, SG_DEBUG, "Updating light parameters." );
205 // calculate lighting parameters based on sun's relative angle to
207 static SGConstPropertyNode_ptr humidity = fgGetNode("/environment/relative-humidity");
208 float av = humidity->getFloatValue() * 45;
209 float visibility_log = log(av)/11.0;
210 float visibility_inv = (45000.0 - av)/45000.0;
212 float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
213 SG_LOG( SG_EVENT, SG_DEBUG, " Sun angle = " << deg );
215 float ambient = _ambient_tbl->interpolate( deg ) + visibility_inv/10;
216 float diffuse = _diffuse_tbl->interpolate( deg );
217 float specular = _specular_tbl->interpolate( deg ) * visibility_log;
218 float sky_brightness = _sky_tbl->interpolate( deg );
220 SG_LOG( SG_EVENT, SG_DEBUG,
221 " ambient = " << ambient << " diffuse = " << diffuse
222 << " specular = " << specular << " sky = " << sky_brightness );
224 // sky_brightness = 0.15; // used to force a dark sky (when testing)
226 // set fog and cloud color
227 float sqrt_sky_brightness = 1.0 - sqrt(1.0 - sky_brightness);
228 _fog_color[0] = base_fog_color[0] * sqrt_sky_brightness;
229 _fog_color[1] = base_fog_color[1] * sqrt_sky_brightness;
230 _fog_color[2] = base_fog_color[2] * sqrt_sky_brightness;
231 _fog_color[3] = base_fog_color[3];
232 gamma_correct_rgb( _fog_color.data() );
235 _sky_color[0] = base_sky_color[0] * sky_brightness;
236 _sky_color[1] = base_sky_color[1] * sky_brightness;
237 _sky_color[2] = base_sky_color[2] * sky_brightness;
238 _sky_color[3] = base_sky_color[3];
239 gamma_correct_rgb( _sky_color.data() );
241 _cloud_color[0] = base_fog_color[0] * sky_brightness;
242 _cloud_color[1] = base_fog_color[1] * sky_brightness;
243 _cloud_color[2] = base_fog_color[2] * sky_brightness;
244 _cloud_color[3] = base_fog_color[3];
246 // adjust the cloud colors for sunrise/sunset effects (darken them)
247 if (_sun_angle > 1.0) {
248 float sun2 = sqrt(_sun_angle);
249 _cloud_color[0] /= sun2;
250 _cloud_color[1] /= sun2;
251 _cloud_color[2] /= sun2;
253 gamma_correct_rgb( _cloud_color.data() );
255 _scene_ambient[0] = _fog_color[0] * ambient;
256 _scene_ambient[1] = _fog_color[1] * ambient;
257 _scene_ambient[2] = _fog_color[2] * ambient;
258 _scene_ambient[3] = 1.0;
259 gamma_correct_rgb( _scene_ambient.data() );
261 SGVec4f color = thesky->get_scene_color();
262 _scene_diffuse[0] = color[0] * diffuse;
263 _scene_diffuse[1] = color[1] * diffuse;
264 _scene_diffuse[2] = color[2] * diffuse;
265 _scene_diffuse[3] = 1.0;
266 gamma_correct_rgb( _scene_diffuse.data() );
268 color = thesky->get_sun_color();
269 _scene_specular[0] = color[0] * specular;
270 _scene_specular[1] = color[1] * specular;
271 _scene_specular[2] = color[2] * specular;
272 _scene_specular[3] = 1.0;
273 gamma_correct_rgb( _scene_specular.data() );
277 // calculate fog color adjusted for sunrise/sunset effects
278 void FGLight::update_adj_fog_color () {
280 double pitch = globals->get_current_view()->getPitch_deg()
281 * SGD_DEGREES_TO_RADIANS;
282 double pitch_offset = globals->get_current_view()-> getPitchOffset_deg()
283 * SGD_DEGREES_TO_RADIANS;
284 double heading = globals->get_current_view()->getHeading_deg()
285 * SGD_DEGREES_TO_RADIANS;
286 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
287 * SGD_DEGREES_TO_RADIANS;
289 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
291 // set fog color (we'll try to match the sunset color in the
292 // direction we are looking
294 // Do some sanity checking ...
295 if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
296 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
300 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
301 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
305 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
306 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
310 double hor_rotation, vert_rotation;
312 // first determine the difference between our view angle and local
313 // direction to the sun
314 vert_rotation = pitch + pitch_offset;
315 hor_rotation = -(_sun_rotation + SGD_PI) - heading + heading_offset;
316 if (hor_rotation < 0 )
317 hor_rotation = fmod(hor_rotation, SGD_2PI) + SGD_2PI;
319 hor_rotation = fmod(hor_rotation, SGD_2PI);
321 // revert to unmodified values before usign them.
323 SGVec4f color = thesky->get_scene_color();
325 gamma_restore_rgb( _fog_color.data() );
326 gamma_restore_rgb( _sky_color.data() );
328 // Calculate the fog color in the direction of the sun for
329 // sunrise/sunset effects.
331 float s_red = color[0]*color[0]*color[0];
332 float s_green = color[1]*color[1]*color[1];
333 float s_blue = color[2]*color[2];
335 // interpolate beween the sunrise/sunset color and the color
336 // at the opposite direction of this effect. Take in account
337 // the current visibility.
339 float av = thesky->get_visibility();
340 if (av > 45000) av = 45000;
342 float avf = 0.87 - (45000 - av) / 83333.33;
343 float sif = 0.5 - cos(_sun_angle*2)/2;
348 float rf1 = fabs((hor_rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
349 float rf2 = avf * pow(rf1*rf1, 1/sif) * 1.0639;
350 float rf3 = 1.0 - rf2;
352 _adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
353 _adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
354 _adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
355 gamma_correct_rgb( _adj_fog_color.data() );
357 // make sure the colors have their original value before they are being
358 // used by the rest of the program.
360 gamma_correct_rgb( _fog_color.data() );
361 gamma_correct_rgb( _sky_color.data() );