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 <Viewer/renderer.hxx>
46 #include <Viewer/view.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 _sun_color(1, 1, 1, 0),
75 _sky_color(0, 0, 0, 0),
76 _fog_color(0, 0, 0, 0),
77 _cloud_color(0, 0, 0, 0),
78 _adj_fog_color(0, 0, 0, 0),
79 _adj_sky_color(0, 0, 0, 0),
97 // initialize lighting tables
98 void FGLight::init () {
99 SG_LOG( SG_EVENT, SG_INFO,
100 "Initializing Lighting interpolation tables." );
102 // build the path names of the lookup tables
103 SGPath path( globals->get_fg_root() );
105 // initialize ambient, diffuse and specular tables
106 SGPath ambient_path = path;
107 ambient_path.append( "Lighting/ambient" );
108 _ambient_tbl = new SGInterpTable( ambient_path.str() );
110 SGPath diffuse_path = path;
111 diffuse_path.append( "Lighting/diffuse" );
112 _diffuse_tbl = new SGInterpTable( diffuse_path.str() );
114 SGPath specular_path = path;
115 specular_path.append( "Lighting/specular" );
116 _specular_tbl = new SGInterpTable( specular_path.str() );
118 // initialize sky table
119 SGPath sky_path = path;
120 sky_path.append( "Lighting/sky" );
121 _sky_tbl = new SGInterpTable( sky_path.str() );
123 globals->get_event_mgr()->addTask("updateSunPos", this,
124 &FGLight::updateSunPos, 0.5 );
128 void FGLight::reinit () {
129 _prev_sun_angle = -9999.0;
134 delete _specular_tbl;
141 update_adj_fog_color();
144 void FGLight::bind () {
145 SGPropertyNode *prop = globals->get_props();
148 tie(prop,"/rendering/scene/saturation", SGRawValuePointer<float>(&_saturation));
149 tie(prop,"/rendering/scene/scattering", SGRawValuePointer<float>(&_scattering));
150 tie(prop,"/rendering/scene/overcast", SGRawValuePointer<float>(&_overcast));
152 _sunAngleRad = prop->getNode("/sim/time/sun-angle-rad", true);
153 _sunAngleRad->setDoubleValue(_sun_angle);
154 _humidity = fgGetNode("/environment/relative-humidity", true);
157 tie(prop,"/rendering/scene/ambient/red", SGRawValuePointer<float>(&_scene_ambient[0]));
158 tie(prop,"/rendering/scene/ambient/green", SGRawValuePointer<float>(&_scene_ambient[1]));
159 tie(prop,"/rendering/scene/ambient/blue", SGRawValuePointer<float>(&_scene_ambient[2]));
160 tie(prop,"/rendering/scene/diffuse/red", SGRawValuePointer<float>(&_scene_diffuse[0]));
161 tie(prop,"/rendering/scene/diffuse/green", SGRawValuePointer<float>(&_scene_diffuse[1]));
162 tie(prop,"/rendering/scene/diffuse/blue", SGRawValuePointer<float>(&_scene_diffuse[2]));
163 tie(prop,"/rendering/scene/specular/red", SGRawValuePointer<float>(&_scene_specular[0]));
164 tie(prop,"/rendering/scene/specular/green", SGRawValuePointer<float>(&_scene_specular[1]));
165 tie(prop,"/rendering/scene/specular/blue", SGRawValuePointer<float>(&_scene_specular[2]));
166 tie(prop,"/rendering/dome/sun/red", SGRawValuePointer<float>(&_sun_color[0]));
167 tie(prop,"/rendering/dome/sun/green", SGRawValuePointer<float>(&_sun_color[1]));
168 tie(prop,"/rendering/dome/sun/blue", SGRawValuePointer<float>(&_sun_color[2]));
169 tie(prop,"/rendering/dome/sky/red", SGRawValuePointer<float>(&_sky_color[0]));
170 tie(prop,"/rendering/dome/sky/green", SGRawValuePointer<float>(&_sky_color[1]));
171 tie(prop,"/rendering/dome/sky/blue", SGRawValuePointer<float>(&_sky_color[2]));
172 tie(prop,"/rendering/dome/cloud/red", SGRawValuePointer<float>(&_cloud_color[0]));
173 tie(prop,"/rendering/dome/cloud/green", SGRawValuePointer<float>(&_cloud_color[1]));
174 tie(prop,"/rendering/dome/cloud/blue", SGRawValuePointer<float>(&_cloud_color[2]));
175 tie(prop,"/rendering/dome/fog/red", SGRawValuePointer<float>(&_fog_color[0]));
176 tie(prop,"/rendering/dome/fog/green", SGRawValuePointer<float>(&_fog_color[1]));
177 tie(prop,"/rendering/dome/fog/blue", SGRawValuePointer<float>(&_fog_color[2]));
180 tie(prop,"/ephemeris/sun/local/x", SGRawValuePointer<float>(&_sun_vec[0]));
181 tie(prop,"/ephemeris/sun/local/y", SGRawValuePointer<float>(&_sun_vec[1]));
182 tie(prop,"/ephemeris/sun/local/z", SGRawValuePointer<float>(&_sun_vec[2]));
184 // Properties used directly by effects
185 _chromeProps[0] = prop->getNode("/rendering/scene/chrome-light/red", true);
186 _chromeProps[1] = prop->getNode("/rendering/scene/chrome-light/green",
188 _chromeProps[2] = prop->getNode("/rendering/scene/chrome-light/blue", true);
189 _chromeProps[3] = prop->getNode("/rendering/scene/chrome-light/alpha",
191 for (int i = 0; i < 4; ++i)
192 _chromeProps[i]->setValue(0.0);
195 void FGLight::unbind () {
196 _tiedProperties.Untie();
198 for (int i = 0; i < 4; ++i)
199 _chromeProps[i] = SGPropertyNode_ptr();
200 _sunAngleRad = SGPropertyNode_ptr();
201 _humidity = SGPropertyNode_ptr();
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 const SGVec4f base_sky_color( 0.31, 0.43, 0.69, 1.0 );
218 const SGVec4f base_fog_color( 0.63, 0.72, 0.88, 1.0 );
220 // calculate lighting parameters based on sun's relative angle to
222 float av = _humidity->getFloatValue() * 45;
223 float visibility_log = log(av)/11.0;
224 float visibility_inv = (45000.0 - av)/45000.0;
226 float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
228 if (_saturation < 0.0) _saturation = 0.0;
229 else if (_saturation > 1.0) _saturation = 1.0;
230 if (_scattering < 0.0) _scattering = 0.0;
231 else if (_scattering > 1.0) _scattering = 1.0;
232 if (_overcast < 0.0) _overcast = 0.0;
233 else if (_overcast > 1.0) _overcast = 1.0;
235 float ambient = _ambient_tbl->interpolate( deg ) + visibility_inv/10;
236 float diffuse = _diffuse_tbl->interpolate( deg );
237 float specular = _specular_tbl->interpolate( deg ) * visibility_log;
238 float sky_brightness = _sky_tbl->interpolate( deg );
240 ambient *= _saturation;
241 diffuse *= _saturation;
242 specular *= _saturation;
243 sky_brightness *= _saturation;
245 // sky_brightness = 0.15; // used to force a dark sky (when testing)
248 float sqr_sky_brightness = sky_brightness * sky_brightness * _scattering;
249 _fog_color = base_fog_color * sqr_sky_brightness;
250 _fog_color[3] = base_fog_color[3];
251 gamma_correct_rgb( _fog_color.data() );
254 static const SGVec4f one_vec( 1.0f, 1.0f, 1.0f, 1.0f);
255 SGVec4f overcast_color = (one_vec - base_sky_color) * _overcast;
256 _sky_color = (base_sky_color + overcast_color) * sky_brightness;
257 _sky_color[3] = base_sky_color[3];
258 gamma_correct_rgb( _sky_color.data() );
261 _cloud_color = base_fog_color * sky_brightness;
263 /** adjust the cloud colors for sunrise/sunset effects (darken them) */
264 if (_sun_angle > 1.0) {
265 float sun2 = 1.0 / sqrt(_sun_angle);
266 _cloud_color *= sun2;
268 _cloud_color[3] = base_fog_color[3];
269 gamma_correct_rgb( _cloud_color.data() );
272 _scene_ambient = _fog_color * ambient;
273 _scene_ambient[3] = _fog_color[3];
274 gamma_correct_rgb( _scene_ambient.data() );
277 SGSky* thesky = globals->get_renderer()->getSky();
278 SGVec4f color = thesky->get_scene_color();
279 _scene_diffuse = color * diffuse;
280 _scene_diffuse[3] = color[3];
281 gamma_correct_rgb( _scene_diffuse.data() );
283 SGVec4f chrome = _scene_ambient * .4f + _scene_diffuse;
285 if (chrome != _scene_chrome) {
286 _scene_chrome = chrome;
287 for (int i = 0; i < 4; ++i)
288 _chromeProps[i]->setValue(static_cast<double>(_scene_chrome[i]));
291 /** specular light */
292 _sun_color = thesky->get_sun_color();
293 _scene_specular = _sun_color * specular;
294 _scene_specular[3] = _sun_color[3];
295 gamma_correct_rgb( _scene_specular.data() );
299 // calculate fog color adjusted for sunrise/sunset effects
300 void FGLight::update_adj_fog_color () {
302 // double pitch = globals->get_current_view()->getPitch_deg()
303 // * SGD_DEGREES_TO_RADIANS;
304 // double pitch_offset = globals->get_current_view()-> getPitchOffset_deg()
305 // * SGD_DEGREES_TO_RADIANS;
306 double heading = globals->get_current_view()->getHeading_deg()
307 * SGD_DEGREES_TO_RADIANS;
308 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
309 * SGD_DEGREES_TO_RADIANS;
311 // set fog color (we'll try to match the sunset color in the
312 // direction we are looking
314 // Do some sanity checking ...
315 if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
316 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
320 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
321 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
325 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
326 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
330 static float gamma = system_gamma;
332 // first determine the difference between our view angle and local
333 // direction to the sun
334 //double vert_rotation = pitch + pitch_offset;
336 // revert to unmodified values before using them.
338 SGSky* thesky = globals->get_renderer()->getSky();
339 SGVec4f color = thesky->get_scene_color();
341 gamma_restore_rgb( _fog_color.data(), gamma );
342 gamma_restore_rgb( _sky_color.data(), gamma );
344 // Calculate the fog color in the direction of the sun for
345 // sunrise/sunset effects.
347 _sun_color[0] = color[0]*color[0]*color[0];
348 _sun_color[1] = color[1]*color[1]*color[1];
349 _sun_color[2] = color[2]*color[2];
351 // interpolate between the sunrise/sunset color and the color
352 // at the opposite direction of this effect. Take in account
353 // the current visibility.
355 float av = thesky->get_visibility();
356 if (av > 45000) av = 45000;
358 float avf = 0.87 - (45000 - av) / 83333.33;
359 float sif = 0.5 - cos(_sun_angle*2)/2;
364 // determine horizontal angle between current view direction and sun
365 // since _sun_rotation is relative to South, and heading is in the local frame
366 // we need to account for the 180 degrees offset and differing signs
367 // hence the negation and SGD_PI adjustment.
368 double hor_rotation = -_sun_rotation - SGD_PI - heading + heading_offset;
369 if (hor_rotation < 0 )
370 hor_rotation = fmod(hor_rotation, SGD_2PI) + SGD_2PI;
372 hor_rotation = fmod(hor_rotation, SGD_2PI);
374 float rf1 = fabs((hor_rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
375 float rf2 = avf * pow(rf1*rf1, 1/sif) * 1.0639 * _saturation * _scattering;
376 float rf3 = 1.0 - rf2;
378 gamma = system_gamma * (0.9 - sif*avf);
379 _adj_fog_color = rf3 * _fog_color + rf2 * _sun_color;
380 _adj_fog_color[3] = 0;
381 gamma_correct_rgb( _adj_fog_color.data(), gamma);
383 // make sure the colors have their original value before they are being
384 // used by the rest of the program.
386 gamma_correct_rgb( _fog_color.data(), gamma );
387 gamma_correct_rgb( _sky_color.data(), gamma );
390 // update the cur_time_params structure with the current sun position
391 void FGLight::updateSunPos()
393 SGTime *t = globals->get_time_params();
395 fgSunPositionGST(t->getGst(), &_sun_lon, &_sun_lat);
397 // It might seem that sun_gc_lat needs to be converted to geodetic
398 // latitude here, but it doesn't. The sun latitude is the latitude
399 // of the point on the earth where the up vector has the same
400 // angle from geocentric Z as the sun direction. But geodetic
401 // latitude is defined as 90 - angle of up vector from Z!
402 SGVec3d sunpos = SGVec3d::fromGeoc(SGGeoc::fromRadM(_sun_lon, _sun_lat,
405 // update the sun light vector
406 _sun_vec = SGVec4f(toVec3f(normalize(sunpos)), 0);
407 _sun_vec_inv = - _sun_vec;
409 // calculate the sun's relative angle to local up
410 SGQuatd hlOr = SGQuatd::fromLonLat( globals->get_view_position() );
411 SGVec3d world_up = hlOr.backTransform( -SGVec3d::e3() );
412 // cout << "nup = " << nup[0] << "," << nup[1] << ","
413 // << nup[2] << endl;
414 // cout << "nsun = " << nsun[0] << "," << nsun[1] << ","
415 // << nsun[2] << endl;
417 SGVec3d nsun = normalize(sunpos);
418 SGVec3d nup = normalize(world_up);
419 _sun_angle = acos( dot( nup, nsun ) );
421 double signedPI = (_sun_angle < 0.0) ? -SGD_PI : SGD_PI;
422 _sun_angle = fmod(_sun_angle+signedPI, SGD_2PI) - signedPI;
424 // Get direction to the sun in the local frame.
425 SGVec3d local_sun_vec = hlOr.transform(nsun);
428 // atan2(y,x) returns the angle between the positive X-axis
429 // and the vector with the origin at 0, going through (x,y)
430 // Since the local frame coordinates have x-positive pointing Nord and
431 // y-positive pointing East we need to negate local_sun_vec.x()
432 // _sun_rotation is positive counterclockwise from South (sun in the East)
433 // and negative clockwise from South (sun in the West)
434 _sun_rotation = atan2(local_sun_vec.y(), -local_sun_vec.x());
436 // cout << " Sky needs to rotate = " << _sun_rotation << " rads = "
437 // << _sun_rotation * SGD_RADIANS_TO_DEGREES << " degrees." << endl;
439 _sunAngleRad->setDoubleValue(_sun_angle);