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>
39 #include <simgear/timing/sg_time.hxx>
40 #include <simgear/structure/event_mgr.hxx>
42 #include <Main/main.hxx>
43 #include <Main/globals.hxx>
44 #include <Main/fg_props.hxx>
45 #include <Main/renderer.hxx>
46 #include <Main/viewer.hxx>
49 #include "sunsolver.hxx"
53 : _ambient_tbl( NULL ),
55 _specular_tbl( NULL ),
62 _moon_vec(0, 0, 0, 0),
63 _sun_vec_inv(0, 0, 0, 0),
64 _moon_vec_inv(0, 0, 0, 0),
70 _scene_ambient(0, 0, 0, 0),
71 _scene_diffuse(0, 0, 0, 0),
72 _scene_specular(0, 0, 0, 0),
73 _scene_chrome(0, 0, 0, 0),
74 _sky_color(0, 0, 0, 0),
75 _fog_color(0, 0, 0, 0),
76 _cloud_color(0, 0, 0, 0),
77 _adj_fog_color(0, 0, 0, 0),
78 _adj_sky_color(0, 0, 0, 0),
95 // initialize lighting tables
96 void FGLight::init () {
97 SG_LOG( SG_EVENT, SG_INFO,
98 "Initializing Lighting interpolation tables." );
100 // build the path names of the lookup tables
101 SGPath path( globals->get_fg_root() );
103 // initialize ambient, diffuse and specular tables
104 SGPath ambient_path = path;
105 ambient_path.append( "Lighting/ambient" );
106 _ambient_tbl = new SGInterpTable( ambient_path.str() );
108 SGPath diffuse_path = path;
109 diffuse_path.append( "Lighting/diffuse" );
110 _diffuse_tbl = new SGInterpTable( diffuse_path.str() );
112 SGPath specular_path = path;
113 specular_path.append( "Lighting/specular" );
114 _specular_tbl = new SGInterpTable( specular_path.str() );
116 // initialize sky table
117 SGPath sky_path = path;
118 sky_path.append( "Lighting/sky" );
119 _sky_tbl = new SGInterpTable( sky_path.str() );
121 globals->get_event_mgr()->addTask("updateSunPos", this,
122 &FGLight::updateSunPos, 0.5 );
126 void FGLight::reinit () {
127 _prev_sun_angle = -9999.0;
132 delete _specular_tbl;
139 update_adj_fog_color();
142 void FGLight::bind () {
143 SGPropertyNode *prop = globals->get_props();
146 prop->tie("/rendering/scene/saturation",SGRawValuePointer<float>(&_saturation));
147 prop->tie("/rendering/scene/scattering",SGRawValuePointer<float>(&_scattering));
150 prop->tie("/sim/time/sun-angle-rad",SGRawValuePointer<double>(&_sun_angle));
151 prop->tie("/rendering/scene/ambient/red",SGRawValuePointer<float>(&_scene_ambient[0]));
152 prop->tie("/rendering/scene/ambient/green",SGRawValuePointer<float>(&_scene_ambient[1]));
153 prop->tie("/rendering/scene/ambient/blue",SGRawValuePointer<float>(&_scene_ambient[2]));
154 prop->tie("/rendering/scene/diffuse/red",SGRawValuePointer<float>(&_scene_diffuse[0]));
155 prop->tie("/rendering/scene/diffuse/green",SGRawValuePointer<float>(&_scene_diffuse[1]));
156 prop->tie("/rendering/scene/diffuse/blue",SGRawValuePointer<float>(&_scene_diffuse[2]));
157 prop->tie("/rendering/scene/specular/red",SGRawValuePointer<float>(&_scene_specular[0]));
158 prop->tie("/rendering/scene/specular/green",SGRawValuePointer<float>(&_scene_specular[1]));
159 prop->tie("/rendering/scene/specular/blue",SGRawValuePointer<float>(&_scene_specular[2]));
160 prop->tie("/rendering/dome/sky/red",SGRawValuePointer<float>(&_sky_color[0]));
161 prop->tie("/rendering/dome/sky/green",SGRawValuePointer<float>(&_sky_color[1]));
162 prop->tie("/rendering/dome/sky/blue",SGRawValuePointer<float>(&_sky_color[2]));
163 prop->tie("/rendering/dome/fog/red",SGRawValuePointer<float>(&_fog_color[0]));
164 prop->tie("/rendering/dome/fog/green",SGRawValuePointer<float>(&_fog_color[1]));
165 prop->tie("/rendering/dome/fog/blue",SGRawValuePointer<float>(&_fog_color[2]));
166 // Properties used directly by effects
167 _chromeProps[0] = prop->getNode("/rendering/scene/chrome-light/red", true);
168 _chromeProps[1] = prop->getNode("/rendering/scene/chrome-light/green",
170 _chromeProps[2] = prop->getNode("/rendering/scene/chrome-light/blue", true);
171 _chromeProps[3] = prop->getNode("/rendering/scene/chrome-light/alpha",
173 for (int i = 0; i < 4; ++i)
174 _chromeProps[i]->setValue(0.0);
177 void FGLight::unbind () {
178 SGPropertyNode *prop = globals->get_props();
179 prop->untie("/rendering/scene/saturation");
180 prop->untie("/rendering/scene/scattering");
181 prop->untie("/environment/relative-humidity");
183 prop->untie("/sim/time/sun-angle-rad");
184 prop->untie("/rendering/scene/ambient/red");
185 prop->untie("/rendering/scene/ambient/green");
186 prop->untie("/rendering/scene/ambient/blue");
187 prop->untie("/rendering/scene/diffuse/red");
188 prop->untie("/rendering/scene/diffuse/green");
189 prop->untie("/rendering/scene/diffuse/blue");
190 prop->untie("/rendering/scene/specular/red");
191 prop->untie("/rendering/scene/specular/green");
192 prop->untie("/rendering/scene/specular/blue");
193 prop->untie("/rendering/dome/sun/red");
194 prop->untie("/rendering/dome/sun/green");
195 prop->untie("/rendering/dome/sun/blue");
196 prop->untie("/rendering/dome/sky/red");
197 prop->untie("/rendering/dome/sky/green");
198 prop->untie("/rendering/dome/sky/blue");
199 prop->untie("/rendering/dome/fog/red");
200 prop->untie("/rendering/dome/fog/green");
201 prop->untie("/rendering/dome/fog/blue");
205 // update lighting parameters based on current sun position
206 void FGLight::update( double dt )
208 update_adj_fog_color();
210 if (_prev_sun_angle != _sun_angle) {
211 _prev_sun_angle = _sun_angle;
216 void FGLight::update_sky_color () {
217 // if the 4th field is 0.0, this specifies a direction ...
218 // const GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
219 const GLfloat base_sky_color[4] = { 0.31, 0.43, 0.69, 1.0 };
220 const GLfloat base_fog_color[4] = { 0.63, 0.72, 0.88, 1.0 };
222 SG_LOG( SG_EVENT, SG_DEBUG, "Updating light parameters." );
224 // calculate lighting parameters based on sun's relative angle to
226 static SGConstPropertyNode_ptr humidity = fgGetNode("/environment/relative-humidity");
227 float av = humidity->getFloatValue() * 45;
228 float visibility_log = log(av)/11.0;
229 float visibility_inv = (45000.0 - av)/45000.0;
231 float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
232 SG_LOG( SG_EVENT, SG_DEBUG, " Sun angle = " << deg );
234 if (_saturation < 0.0) _saturation = 0.0;
235 else if (_saturation > 1.0) _saturation = 1.0;
236 if (_scattering < 0.0) _scattering = 0.0;
237 else if (_scattering > 1.0) _scattering = 1.0;
239 float ambient = _ambient_tbl->interpolate( deg ) + visibility_inv/10;
240 float diffuse = _diffuse_tbl->interpolate( deg );
241 float specular = _specular_tbl->interpolate( deg ) * visibility_log;
242 float sky_brightness = _sky_tbl->interpolate( deg );
244 ambient *= _saturation;
245 diffuse *= _saturation;
246 specular *= _saturation;
247 sky_brightness *= _saturation;
249 SG_LOG( SG_EVENT, SG_DEBUG,
250 " ambient = " << ambient << " diffuse = " << diffuse
251 << " specular = " << specular << " sky = " << sky_brightness );
253 // sky_brightness = 0.15; // used to force a dark sky (when testing)
255 // set fog and cloud color
256 float sqrt_sky_brightness = (1.0 - sqrt(1.0 - sky_brightness))*_scattering;
257 _fog_color[0] = base_fog_color[0] * sqrt_sky_brightness;
258 _fog_color[1] = base_fog_color[1] * sqrt_sky_brightness;
259 _fog_color[2] = base_fog_color[2] * sqrt_sky_brightness;
260 _fog_color[3] = base_fog_color[3];
261 gamma_correct_rgb( _fog_color.data() );
264 _sky_color[0] = base_sky_color[0] * sky_brightness;
265 _sky_color[1] = base_sky_color[1] * sky_brightness;
266 _sky_color[2] = base_sky_color[2] * sky_brightness;
267 _sky_color[3] = base_sky_color[3];
268 gamma_correct_rgb( _sky_color.data() );
270 _cloud_color[0] = base_fog_color[0] * sky_brightness;
271 _cloud_color[1] = base_fog_color[1] * sky_brightness;
272 _cloud_color[2] = base_fog_color[2] * sky_brightness;
273 _cloud_color[3] = base_fog_color[3];
275 // adjust the cloud colors for sunrise/sunset effects (darken them)
276 if (_sun_angle > 1.0) {
277 float sun2 = sqrt(_sun_angle);
278 _cloud_color[0] /= sun2;
279 _cloud_color[1] /= sun2;
280 _cloud_color[2] /= sun2;
282 gamma_correct_rgb( _cloud_color.data() );
284 _scene_ambient[0] = _fog_color[0] * ambient;
285 _scene_ambient[1] = _fog_color[1] * ambient;
286 _scene_ambient[2] = _fog_color[2] * ambient;
287 _scene_ambient[3] = 1.0;
288 gamma_correct_rgb( _scene_ambient.data() );
290 SGVec4f color = thesky->get_scene_color();
291 _scene_diffuse[0] = color[0] * diffuse;
292 _scene_diffuse[1] = color[1] * diffuse;
293 _scene_diffuse[2] = color[2] * diffuse;
294 _scene_diffuse[3] = 1.0;
295 gamma_correct_rgb( _scene_diffuse.data() );
297 SGVec4f chrome = _scene_ambient * .4f + _scene_diffuse;
299 if (chrome != _scene_chrome) {
300 _scene_chrome = chrome;
301 for (int i = 0; i < 4; ++i)
302 _chromeProps[i]->setValue(static_cast<double>(_scene_chrome[i]));
305 color = thesky->get_sun_color();
306 _scene_specular[0] = color[0] * specular;
307 _scene_specular[1] = color[1] * specular;
308 _scene_specular[2] = color[2] * specular;
309 _scene_specular[3] = 1.0;
310 gamma_correct_rgb( _scene_specular.data() );
314 // calculate fog color adjusted for sunrise/sunset effects
315 void FGLight::update_adj_fog_color () {
317 double pitch = globals->get_current_view()->getPitch_deg()
318 * SGD_DEGREES_TO_RADIANS;
319 double pitch_offset = globals->get_current_view()-> getPitchOffset_deg()
320 * SGD_DEGREES_TO_RADIANS;
321 double heading = globals->get_current_view()->getHeading_deg()
322 * SGD_DEGREES_TO_RADIANS;
323 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
324 * SGD_DEGREES_TO_RADIANS;
326 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
328 // set fog color (we'll try to match the sunset color in the
329 // direction we are looking
331 // Do some sanity checking ...
332 if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
333 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
337 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
338 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
342 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
343 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
347 double hor_rotation, vert_rotation;
348 static float gamma = system_gamma;
350 // first determine the difference between our view angle and local
351 // direction to the sun
352 vert_rotation = pitch + pitch_offset;
353 hor_rotation = -(_sun_rotation + SGD_PI) - heading + heading_offset;
354 if (hor_rotation < 0 )
355 hor_rotation = fmod(hor_rotation, SGD_2PI) + SGD_2PI;
357 hor_rotation = fmod(hor_rotation, SGD_2PI);
359 // revert to unmodified values before using them.
361 SGVec4f color = thesky->get_scene_color();
363 gamma_restore_rgb( _fog_color.data(), gamma );
364 gamma_restore_rgb( _sky_color.data(), gamma );
366 // Calculate the fog color in the direction of the sun for
367 // sunrise/sunset effects.
369 float s_red = color[0]*color[0]*color[0];
370 float s_green = color[1]*color[1]*color[1];
371 float s_blue = color[2]*color[2];
373 // interpolate between the sunrise/sunset color and the color
374 // at the opposite direction of this effect. Take in account
375 // the current visibility.
377 float av = thesky->get_visibility();
378 if (av > 45000) av = 45000;
380 float avf = 0.87 - (45000 - av) / 83333.33;
381 float sif = 0.5 - cos(_sun_angle*2)/2;
386 float rf1 = fabs((hor_rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
387 float rf2 = avf * pow(rf1*rf1, 1/sif) * 1.0639 * _saturation * _scattering;
388 float rf3 = 1.0 - rf2;
390 gamma = system_gamma * (0.9 - sif*avf);
391 _adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
392 _adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
393 _adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
394 gamma_correct_rgb( _adj_fog_color.data(), gamma);
396 // make sure the colors have their original value before they are being
397 // used by the rest of the program.
399 gamma_correct_rgb( _fog_color.data(), gamma );
400 gamma_correct_rgb( _sky_color.data(), gamma );
403 // update the cur_time_params structure with the current sun position
404 void FGLight::updateSunPos()
406 SGTime *t = globals->get_time_params();
407 FGViewer *v = globals->get_current_view();
409 SG_LOG( SG_EVENT, SG_DEBUG, " Updating Sun position" );
410 SG_LOG( SG_EVENT, SG_DEBUG, " Gst = " << t->getGst() );
412 fgSunPositionGST(t->getGst(), &_sun_lon, &_sun_lat);
413 // It might seem that sun_gc_lat needs to be converted to geodetic
414 // latitude here, but it doesn't. The sun latitude is the latitude
415 // of the point on the earth where the up vector has the same
416 // angle from geocentric Z as the sun direction. But geodetic
417 // latitude is defined as 90 - angle of up vector from Z!
418 SGVec3d sunpos(SGVec3d::fromGeoc(SGGeoc::fromRadM(_sun_lon, _sun_lat,
419 SGGeodesy::EQURAD)));
421 SG_LOG( SG_EVENT, SG_DEBUG, " t->cur_time = " << t->get_cur_time() );
422 SG_LOG( SG_EVENT, SG_DEBUG,
423 " Sun Geocentric lat = " << _sun_lat
424 << " Geodcentric lat = " << _sun_lat );
426 // update the sun light vector
427 sun_vec() = SGVec4f(toVec3f(normalize(sunpos)), 0);
428 sun_vec_inv() = - sun_vec();
430 // calculate the sun's relative angle to local up
431 SGVec3d viewPos = v->get_view_pos();
432 SGQuatd hlOr = SGQuatd::fromLonLat(SGGeod::fromCart(viewPos));
433 SGVec3d world_up = hlOr.backTransform(-SGVec3d::e3());
434 SGVec3d nsun = normalize(sunpos);
435 // cout << "nup = " << nup[0] << "," << nup[1] << ","
436 // << nup[2] << endl;
437 // cout << "nsun = " << nsun[0] << "," << nsun[1] << ","
438 // << nsun[2] << endl;
440 _sun_angle = acos( dot ( world_up, nsun ) );
441 SG_LOG( SG_EVENT, SG_DEBUG, "sun angle relative to current location = "
442 << get_sun_angle() );
444 // Get direction to the sun in the local frame.
445 SGVec3d local_sun_vec = hlOr.transform(nsun);
447 // Angle from south. XXX Is this correct in the southern hemisphere?
448 _sun_rotation = atan2(local_sun_vec.x(), -local_sun_vec.y());
450 // cout << " Sky needs to rotate = " << _sun_rotation << " rads = "
451 // << _sun_rotation * SGD_RADIANS_TO_DEGREES << " degrees." << endl;