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),
96 // initialize lighting tables
97 void FGLight::init () {
98 SG_LOG( SG_EVENT, SG_INFO,
99 "Initializing Lighting interpolation tables." );
101 // build the path names of the lookup tables
102 SGPath path( globals->get_fg_root() );
104 // initialize ambient, diffuse and specular tables
105 SGPath ambient_path = path;
106 ambient_path.append( "Lighting/ambient" );
107 _ambient_tbl = new SGInterpTable( ambient_path.str() );
109 SGPath diffuse_path = path;
110 diffuse_path.append( "Lighting/diffuse" );
111 _diffuse_tbl = new SGInterpTable( diffuse_path.str() );
113 SGPath specular_path = path;
114 specular_path.append( "Lighting/specular" );
115 _specular_tbl = new SGInterpTable( specular_path.str() );
117 // initialize sky table
118 SGPath sky_path = path;
119 sky_path.append( "Lighting/sky" );
120 _sky_tbl = new SGInterpTable( sky_path.str() );
122 globals->get_event_mgr()->addTask("updateSunPos", this,
123 &FGLight::updateSunPos, 0.5 );
127 void FGLight::reinit () {
128 _prev_sun_angle = -9999.0;
133 delete _specular_tbl;
140 update_adj_fog_color();
143 void FGLight::bind () {
144 SGPropertyNode *prop = globals->get_props();
147 prop->tie("/rendering/scene/saturation",SGRawValuePointer<float>(&_saturation));
148 prop->tie("/rendering/scene/scattering",SGRawValuePointer<float>(&_scattering));
149 prop->tie("/environment/relative-humidity",SGRawValuePointer<float>(&_humidity));
152 prop->tie("/sim/time/sun-angle-rad",SGRawValuePointer<double>(&_sun_angle));
153 prop->tie("/rendering/scene/ambient/red",SGRawValuePointer<float>(&_scene_ambient[0]));
154 prop->tie("/rendering/scene/ambient/green",SGRawValuePointer<float>(&_scene_ambient[1]));
155 prop->tie("/rendering/scene/ambient/blue",SGRawValuePointer<float>(&_scene_ambient[2]));
156 prop->tie("/rendering/scene/diffuse/red",SGRawValuePointer<float>(&_scene_diffuse[0]));
157 prop->tie("/rendering/scene/diffuse/green",SGRawValuePointer<float>(&_scene_diffuse[1]));
158 prop->tie("/rendering/scene/diffuse/blue",SGRawValuePointer<float>(&_scene_diffuse[2]));
159 prop->tie("/rendering/scene/specular/red",SGRawValuePointer<float>(&_scene_specular[0]));
160 prop->tie("/rendering/scene/specular/green",SGRawValuePointer<float>(&_scene_specular[1]));
161 prop->tie("/rendering/scene/specular/blue",SGRawValuePointer<float>(&_scene_specular[2]));
162 prop->tie("/rendering/dome/sky/red",SGRawValuePointer<float>(&_sky_color[0]));
163 prop->tie("/rendering/dome/sky/green",SGRawValuePointer<float>(&_sky_color[1]));
164 prop->tie("/rendering/dome/sky/blue",SGRawValuePointer<float>(&_sky_color[2]));
165 prop->tie("/rendering/dome/fog/red",SGRawValuePointer<float>(&_fog_color[0]));
166 prop->tie("/rendering/dome/fog/green",SGRawValuePointer<float>(&_fog_color[1]));
167 prop->tie("/rendering/dome/fog/blue",SGRawValuePointer<float>(&_fog_color[2]));
168 // Properties used directly by effects
169 _chromeProps[0] = prop->getNode("/rendering/scene/chrome-light/red", true);
170 _chromeProps[1] = prop->getNode("/rendering/scene/chrome-light/green",
172 _chromeProps[2] = prop->getNode("/rendering/scene/chrome-light/blue", true);
173 _chromeProps[3] = prop->getNode("/rendering/scene/chrome-light/alpha",
175 for (int i = 0; i < 4; ++i)
176 _chromeProps[i]->setValue(0.0);
179 void FGLight::unbind () {
180 SGPropertyNode *prop = globals->get_props();
181 prop->untie("/rendering/scene/saturation");
182 prop->untie("/rendering/scene/scattering");
183 prop->untie("/environment/relative-humidity");
185 prop->untie("/sim/time/sun-angle-rad");
186 prop->untie("/rendering/scene/ambient/red");
187 prop->untie("/rendering/scene/ambient/green");
188 prop->untie("/rendering/scene/ambient/blue");
189 prop->untie("/rendering/scene/diffuse/red");
190 prop->untie("/rendering/scene/diffuse/green");
191 prop->untie("/rendering/scene/diffuse/blue");
192 prop->untie("/rendering/scene/specular/red");
193 prop->untie("/rendering/scene/specular/green");
194 prop->untie("/rendering/scene/specular/blue");
195 prop->untie("/rendering/dome/sun/red");
196 prop->untie("/rendering/dome/sun/green");
197 prop->untie("/rendering/dome/sun/blue");
198 prop->untie("/rendering/dome/sky/red");
199 prop->untie("/rendering/dome/sky/green");
200 prop->untie("/rendering/dome/sky/blue");
201 prop->untie("/rendering/dome/fog/red");
202 prop->untie("/rendering/dome/fog/green");
203 prop->untie("/rendering/dome/fog/blue");
207 // update lighting parameters based on current sun position
208 void FGLight::update( double dt )
210 update_adj_fog_color();
212 if (_prev_sun_angle != _sun_angle) {
213 _prev_sun_angle = _sun_angle;
218 void FGLight::update_sky_color () {
219 // if the 4th field is 0.0, this specifies a direction ...
220 // const GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
221 const GLfloat base_sky_color[4] = { 0.31, 0.43, 0.69, 1.0 };
222 const GLfloat base_fog_color[4] = { 0.63, 0.72, 0.88, 1.0 };
224 SG_LOG( SG_EVENT, SG_DEBUG, "Updating light parameters." );
226 // calculate lighting parameters based on sun's relative angle to
228 float av = _humidity * 45;
229 float visibility_log = log(av)/11.0;
230 float visibility_inv = (45000.0 - av)/45000.0;
232 float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
233 SG_LOG( SG_EVENT, SG_DEBUG, " Sun angle = " << deg );
235 if (_saturation < 0.0) _saturation = 0.0;
236 else if (_saturation > 1.0) _saturation = 1.0;
237 if (_scattering < 0.0) _scattering = 0.0;
238 else if (_scattering > 1.0) _scattering = 1.0;
240 float ambient = _ambient_tbl->interpolate( deg ) + visibility_inv/10;
241 float diffuse = _diffuse_tbl->interpolate( deg );
242 float specular = _specular_tbl->interpolate( deg ) * visibility_log;
243 float sky_brightness = _sky_tbl->interpolate( deg );
245 ambient *= _saturation;
246 diffuse *= _saturation;
247 specular *= _saturation;
248 sky_brightness *= _saturation;
250 SG_LOG( SG_EVENT, SG_DEBUG,
251 " ambient = " << ambient << " diffuse = " << diffuse
252 << " specular = " << specular << " sky = " << sky_brightness );
254 // sky_brightness = 0.15; // used to force a dark sky (when testing)
256 // set fog and cloud color
257 float sqrt_sky_brightness = (1.0 - sqrt(1.0 - sky_brightness))*_scattering;
258 _fog_color[0] = base_fog_color[0] * sqrt_sky_brightness;
259 _fog_color[1] = base_fog_color[1] * sqrt_sky_brightness;
260 _fog_color[2] = base_fog_color[2] * sqrt_sky_brightness;
261 _fog_color[3] = base_fog_color[3];
262 gamma_correct_rgb( _fog_color.data() );
265 _sky_color[0] = base_sky_color[0] * sky_brightness;
266 _sky_color[1] = base_sky_color[1] * sky_brightness;
267 _sky_color[2] = base_sky_color[2] * sky_brightness;
268 _sky_color[3] = base_sky_color[3];
269 gamma_correct_rgb( _sky_color.data() );
271 _cloud_color[0] = base_fog_color[0] * sky_brightness;
272 _cloud_color[1] = base_fog_color[1] * sky_brightness;
273 _cloud_color[2] = base_fog_color[2] * sky_brightness;
274 _cloud_color[3] = base_fog_color[3];
276 // adjust the cloud colors for sunrise/sunset effects (darken them)
277 if (_sun_angle > 1.0) {
278 float sun2 = sqrt(_sun_angle);
279 _cloud_color[0] /= sun2;
280 _cloud_color[1] /= sun2;
281 _cloud_color[2] /= sun2;
283 gamma_correct_rgb( _cloud_color.data() );
285 _scene_ambient[0] = _fog_color[0] * ambient;
286 _scene_ambient[1] = _fog_color[1] * ambient;
287 _scene_ambient[2] = _fog_color[2] * ambient;
288 _scene_ambient[3] = 1.0;
289 gamma_correct_rgb( _scene_ambient.data() );
291 SGVec4f color = thesky->get_scene_color();
292 _scene_diffuse[0] = color[0] * diffuse;
293 _scene_diffuse[1] = color[1] * diffuse;
294 _scene_diffuse[2] = color[2] * diffuse;
295 _scene_diffuse[3] = 1.0;
296 gamma_correct_rgb( _scene_diffuse.data() );
298 SGVec4f chrome = _scene_ambient * .4f + _scene_diffuse;
300 if (chrome != _scene_chrome) {
301 _scene_chrome = chrome;
302 for (int i = 0; i < 4; ++i)
303 _chromeProps[i]->setValue(static_cast<double>(_scene_chrome[i]));
306 color = thesky->get_sun_color();
307 _scene_specular[0] = color[0] * specular;
308 _scene_specular[1] = color[1] * specular;
309 _scene_specular[2] = color[2] * specular;
310 _scene_specular[3] = 1.0;
311 gamma_correct_rgb( _scene_specular.data() );
315 // calculate fog color adjusted for sunrise/sunset effects
316 void FGLight::update_adj_fog_color () {
318 double pitch = globals->get_current_view()->getPitch_deg()
319 * SGD_DEGREES_TO_RADIANS;
320 double pitch_offset = globals->get_current_view()-> getPitchOffset_deg()
321 * SGD_DEGREES_TO_RADIANS;
322 double heading = globals->get_current_view()->getHeading_deg()
323 * SGD_DEGREES_TO_RADIANS;
324 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
325 * SGD_DEGREES_TO_RADIANS;
327 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
329 // set fog color (we'll try to match the sunset color in the
330 // direction we are looking
332 // Do some sanity checking ...
333 if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
334 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
338 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
339 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
343 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
344 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
348 double hor_rotation, vert_rotation;
349 static float gamma = system_gamma;
351 // first determine the difference between our view angle and local
352 // direction to the sun
353 vert_rotation = pitch + pitch_offset;
354 hor_rotation = -(_sun_rotation + SGD_PI) - heading + heading_offset;
355 if (hor_rotation < 0 )
356 hor_rotation = fmod(hor_rotation, SGD_2PI) + SGD_2PI;
358 hor_rotation = fmod(hor_rotation, SGD_2PI);
360 // revert to unmodified values before using them.
362 SGVec4f color = thesky->get_scene_color();
364 gamma_restore_rgb( _fog_color.data(), gamma );
365 gamma_restore_rgb( _sky_color.data(), gamma );
367 // Calculate the fog color in the direction of the sun for
368 // sunrise/sunset effects.
370 float s_red = color[0]*color[0]*color[0];
371 float s_green = color[1]*color[1]*color[1];
372 float s_blue = color[2]*color[2];
374 // interpolate between the sunrise/sunset color and the color
375 // at the opposite direction of this effect. Take in account
376 // the current visibility.
378 float av = thesky->get_visibility();
379 if (av > 45000) av = 45000;
381 float avf = 0.87 - (45000 - av) / 83333.33;
382 float sif = 0.5 - cos(_sun_angle*2)/2;
387 float rf1 = fabs((hor_rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
388 float rf2 = avf * pow(rf1*rf1, 1/sif) * 1.0639 * _saturation * _scattering;
389 float rf3 = 1.0 - rf2;
391 gamma = system_gamma * (0.9 - sif*avf);
392 _adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
393 _adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
394 _adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
395 gamma_correct_rgb( _adj_fog_color.data(), gamma);
397 // make sure the colors have their original value before they are being
398 // used by the rest of the program.
400 gamma_correct_rgb( _fog_color.data(), gamma );
401 gamma_correct_rgb( _sky_color.data(), gamma );
404 // update the cur_time_params structure with the current sun position
405 void FGLight::updateSunPos()
407 SGTime *t = globals->get_time_params();
408 FGViewer *v = globals->get_current_view();
410 SG_LOG( SG_EVENT, SG_DEBUG, " Updating Sun position" );
411 SG_LOG( SG_EVENT, SG_DEBUG, " Gst = " << t->getGst() );
413 fgSunPositionGST(t->getGst(), &_sun_lon, &_sun_lat);
414 // It might seem that sun_gc_lat needs to be converted to geodetic
415 // latitude here, but it doesn't. The sun latitude is the latitude
416 // of the point on the earth where the up vector has the same
417 // angle from geocentric Z as the sun direction. But geodetic
418 // latitude is defined as 90 - angle of up vector from Z!
419 SGVec3d sunpos(SGVec3d::fromGeoc(SGGeoc::fromRadM(_sun_lon, _sun_lat,
420 SGGeodesy::EQURAD)));
422 SG_LOG( SG_EVENT, SG_DEBUG, " t->cur_time = " << t->get_cur_time() );
423 SG_LOG( SG_EVENT, SG_DEBUG,
424 " Sun Geocentric lat = " << _sun_lat
425 << " Geodcentric lat = " << _sun_lat );
427 // update the sun light vector
428 sun_vec() = SGVec4f(toVec3f(normalize(sunpos)), 0);
429 sun_vec_inv() = - sun_vec();
431 // calculate the sun's relative angle to local up
432 SGVec3d viewPos = v->get_view_pos();
433 SGQuatd hlOr = SGQuatd::fromLonLat(SGGeod::fromCart(viewPos));
434 SGVec3d world_up = hlOr.backTransform(-SGVec3d::e3());
435 SGVec3d nsun = normalize(sunpos);
436 // cout << "nup = " << nup[0] << "," << nup[1] << ","
437 // << nup[2] << endl;
438 // cout << "nsun = " << nsun[0] << "," << nsun[1] << ","
439 // << nsun[2] << endl;
441 _sun_angle = acos( dot ( world_up, nsun ) );
442 SG_LOG( SG_EVENT, SG_DEBUG, "sun angle relative to current location = "
443 << get_sun_angle() );
445 // Get direction to the sun in the local frame.
446 SGVec3d local_sun_vec = hlOr.transform(nsun);
448 // Angle from south. XXX Is this correct in the southern hemisphere?
449 _sun_rotation = atan2(local_sun_vec.x(), -local_sun_vec.y());
451 // cout << " Sky needs to rotate = " << _sun_rotation << " rads = "
452 // << _sun_rotation * SGD_RADIANS_TO_DEGREES << " degrees." << endl;