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"
52 * Map i.e. project a vector onto a plane.
53 * @param normal (in) normal vector for the plane
54 * @param v0 (in) a point on the plane
55 * @param vec (in) the vector to map onto the plane
57 static SGVec3f map_vec_onto_cur_surface_plane(const SGVec3f& normal,
61 // calculate a vector "u1" representing the shortest distance from
62 // the plane specified by normal and v0 to a point specified by
63 // "vec". "u1" represents both the direction and magnitude of
64 // this desired distance.
66 // u1 = ( (normal <dot> vec) / (normal <dot> normal) ) * normal
67 SGVec3f u1 = (dot(normal, vec) / dot(normal, normal)) * normal;
69 // calculate the vector "v" which is the vector "vec" mapped onto
70 // the plane specified by "normal" and "v0".
73 SGVec3f v = v0 + vec - u1;
75 // Calculate the vector "result" which is "v" - "v0" which is a
76 // directional vector pointing from v0 towards v
85 : _ambient_tbl( NULL ),
87 _specular_tbl( NULL ),
94 _moon_vec(0, 0, 0, 0),
95 _sun_vec_inv(0, 0, 0, 0),
96 _moon_vec_inv(0, 0, 0, 0),
102 _scene_ambient(0, 0, 0, 0),
103 _scene_diffuse(0, 0, 0, 0),
104 _scene_specular(0, 0, 0, 0),
105 _scene_chrome(0, 0, 0, 0),
106 _sky_color(0, 0, 0, 0),
107 _fog_color(0, 0, 0, 0),
108 _cloud_color(0, 0, 0, 0),
109 _adj_fog_color(0, 0, 0, 0),
110 _adj_sky_color(0, 0, 0, 0),
120 delete _specular_tbl;
125 // initialize lighting tables
126 void FGLight::init () {
127 SG_LOG( SG_EVENT, SG_INFO,
128 "Initializing Lighting interpolation tables." );
130 // build the path names of the lookup tables
131 SGPath path( globals->get_fg_root() );
133 // initialize ambient, diffuse and specular tables
134 SGPath ambient_path = path;
135 ambient_path.append( "Lighting/ambient" );
136 _ambient_tbl = new SGInterpTable( ambient_path.str() );
138 SGPath diffuse_path = path;
139 diffuse_path.append( "Lighting/diffuse" );
140 _diffuse_tbl = new SGInterpTable( diffuse_path.str() );
142 SGPath specular_path = path;
143 specular_path.append( "Lighting/specular" );
144 _specular_tbl = new SGInterpTable( specular_path.str() );
146 // initialize sky table
147 SGPath sky_path = path;
148 sky_path.append( "Lighting/sky" );
149 _sky_tbl = new SGInterpTable( sky_path.str() );
151 globals->get_event_mgr()->addTask("updateSunPos", this,
152 &FGLight::updateSunPos, 0.5 );
156 void FGLight::reinit () {
157 _prev_sun_angle = -9999.0;
162 delete _specular_tbl;
169 update_adj_fog_color();
172 void FGLight::bind () {
173 SGPropertyNode *prop = globals->get_props();
174 prop->tie("/sim/time/sun-angle-rad",SGRawValuePointer<double>(&_sun_angle));
175 prop->tie("/rendering/scene/ambient/red",SGRawValuePointer<float>(&_scene_ambient[0]));
176 prop->tie("/rendering/scene/ambient/green",SGRawValuePointer<float>(&_scene_ambient[1]));
177 prop->tie("/rendering/scene/ambient/blue",SGRawValuePointer<float>(&_scene_ambient[2]));
178 prop->tie("/rendering/scene/diffuse/red",SGRawValuePointer<float>(&_scene_diffuse[0]));
179 prop->tie("/rendering/scene/diffuse/green",SGRawValuePointer<float>(&_scene_diffuse[1]));
180 prop->tie("/rendering/scene/diffuse/blue",SGRawValuePointer<float>(&_scene_diffuse[2]));
181 prop->tie("/rendering/scene/specular/red",SGRawValuePointer<float>(&_scene_specular[0]));
182 prop->tie("/rendering/scene/specular/green",SGRawValuePointer<float>(&_scene_specular[1]));
183 prop->tie("/rendering/scene/specular/blue",SGRawValuePointer<float>(&_scene_specular[2]));
184 prop->tie("/rendering/dome/sky/red",SGRawValuePointer<float>(&_sky_color[0]));
185 prop->tie("/rendering/dome/sky/green",SGRawValuePointer<float>(&_sky_color[1]));
186 prop->tie("/rendering/dome/sky/blue",SGRawValuePointer<float>(&_sky_color[2]));
187 prop->tie("/rendering/dome/fog/red",SGRawValuePointer<float>(&_fog_color[0]));
188 prop->tie("/rendering/dome/fog/green",SGRawValuePointer<float>(&_fog_color[1]));
189 prop->tie("/rendering/dome/fog/blue",SGRawValuePointer<float>(&_fog_color[2]));
190 // Properties used directly by effects
191 _chromeProps[0] = prop->getNode("/rendering/scene/chrome-light/red", true);
192 _chromeProps[1] = prop->getNode("/rendering/scene/chrome-light/green",
194 _chromeProps[2] = prop->getNode("/rendering/scene/chrome-light/blue", true);
195 _chromeProps[3] = prop->getNode("/rendering/scene/chrome-light/alpha",
197 for (int i = 0; i < 4; ++i)
198 _chromeProps[i]->setValue(0.0);
201 void FGLight::unbind () {
202 SGPropertyNode *prop = globals->get_props();
203 prop->untie("/sim/time/sun-angle-rad");
204 prop->untie("/rendering/scene/ambient/red");
205 prop->untie("/rendering/scene/ambient/green");
206 prop->untie("/rendering/scene/ambient/blue");
207 prop->untie("/rendering/scene/diffuse/red");
208 prop->untie("/rendering/scene/diffuse/green");
209 prop->untie("/rendering/scene/diffuse/blue");
210 prop->untie("/rendering/scene/specular/red");
211 prop->untie("/rendering/scene/specular/green");
212 prop->untie("/rendering/scene/specular/blue");
213 prop->untie("/rendering/dome/sun/red");
214 prop->untie("/rendering/dome/sun/green");
215 prop->untie("/rendering/dome/sun/blue");
216 prop->untie("/rendering/dome/sky/red");
217 prop->untie("/rendering/dome/sky/green");
218 prop->untie("/rendering/dome/sky/blue");
219 prop->untie("/rendering/dome/fog/red");
220 prop->untie("/rendering/dome/fog/green");
221 prop->untie("/rendering/dome/fog/blue");
225 // update lighting parameters based on current sun position
226 void FGLight::update( double dt )
228 update_adj_fog_color();
230 if (_prev_sun_angle != _sun_angle) {
231 _prev_sun_angle = _sun_angle;
236 void FGLight::update_sky_color () {
237 // if the 4th field is 0.0, this specifies a direction ...
238 // const GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
239 const GLfloat base_sky_color[4] = { 0.31, 0.43, 0.69, 1.0 };
240 const GLfloat base_fog_color[4] = { 0.63, 0.72, 0.88, 1.0 };
242 SG_LOG( SG_EVENT, SG_DEBUG, "Updating light parameters." );
244 // calculate lighting parameters based on sun's relative angle to
246 static SGConstPropertyNode_ptr humidity = fgGetNode("/environment/relative-humidity");
247 float av = humidity->getFloatValue() * 45;
248 float visibility_log = log(av)/11.0;
249 float visibility_inv = (45000.0 - av)/45000.0;
251 float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
252 SG_LOG( SG_EVENT, SG_DEBUG, " Sun angle = " << deg );
254 float ambient = _ambient_tbl->interpolate( deg ) + visibility_inv/10;
255 float diffuse = _diffuse_tbl->interpolate( deg );
256 float specular = _specular_tbl->interpolate( deg ) * visibility_log;
257 float sky_brightness = _sky_tbl->interpolate( deg );
259 SG_LOG( SG_EVENT, SG_DEBUG,
260 " ambient = " << ambient << " diffuse = " << diffuse
261 << " specular = " << specular << " sky = " << sky_brightness );
263 // sky_brightness = 0.15; // used to force a dark sky (when testing)
265 // set fog and cloud color
266 float sqrt_sky_brightness = 1.0 - sqrt(1.0 - sky_brightness);
267 _fog_color[0] = base_fog_color[0] * sqrt_sky_brightness;
268 _fog_color[1] = base_fog_color[1] * sqrt_sky_brightness;
269 _fog_color[2] = base_fog_color[2] * sqrt_sky_brightness;
270 _fog_color[3] = base_fog_color[3];
271 gamma_correct_rgb( _fog_color.data() );
274 _sky_color[0] = base_sky_color[0] * sky_brightness;
275 _sky_color[1] = base_sky_color[1] * sky_brightness;
276 _sky_color[2] = base_sky_color[2] * sky_brightness;
277 _sky_color[3] = base_sky_color[3];
278 gamma_correct_rgb( _sky_color.data() );
280 _cloud_color[0] = base_fog_color[0] * sky_brightness;
281 _cloud_color[1] = base_fog_color[1] * sky_brightness;
282 _cloud_color[2] = base_fog_color[2] * sky_brightness;
283 _cloud_color[3] = base_fog_color[3];
285 // adjust the cloud colors for sunrise/sunset effects (darken them)
286 if (_sun_angle > 1.0) {
287 float sun2 = sqrt(_sun_angle);
288 _cloud_color[0] /= sun2;
289 _cloud_color[1] /= sun2;
290 _cloud_color[2] /= sun2;
292 gamma_correct_rgb( _cloud_color.data() );
294 _scene_ambient[0] = _fog_color[0] * ambient;
295 _scene_ambient[1] = _fog_color[1] * ambient;
296 _scene_ambient[2] = _fog_color[2] * ambient;
297 _scene_ambient[3] = 1.0;
298 gamma_correct_rgb( _scene_ambient.data() );
300 SGVec4f color = thesky->get_scene_color();
301 _scene_diffuse[0] = color[0] * diffuse;
302 _scene_diffuse[1] = color[1] * diffuse;
303 _scene_diffuse[2] = color[2] * diffuse;
304 _scene_diffuse[3] = 1.0;
305 gamma_correct_rgb( _scene_diffuse.data() );
307 SGVec4f chrome = _scene_ambient * .4f + _scene_diffuse;
309 if (chrome != _scene_chrome) {
310 _scene_chrome = chrome;
311 for (int i = 0; i < 4; ++i)
312 _chromeProps[i]->setValue(static_cast<double>(_scene_chrome[i]));
315 color = thesky->get_sun_color();
316 _scene_specular[0] = color[0] * specular;
317 _scene_specular[1] = color[1] * specular;
318 _scene_specular[2] = color[2] * specular;
319 _scene_specular[3] = 1.0;
320 gamma_correct_rgb( _scene_specular.data() );
324 // calculate fog color adjusted for sunrise/sunset effects
325 void FGLight::update_adj_fog_color () {
327 double pitch = globals->get_current_view()->getPitch_deg()
328 * SGD_DEGREES_TO_RADIANS;
329 double pitch_offset = globals->get_current_view()-> getPitchOffset_deg()
330 * SGD_DEGREES_TO_RADIANS;
331 double heading = globals->get_current_view()->getHeading_deg()
332 * SGD_DEGREES_TO_RADIANS;
333 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
334 * SGD_DEGREES_TO_RADIANS;
336 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
338 // set fog color (we'll try to match the sunset color in the
339 // direction we are looking
341 // Do some sanity checking ...
342 if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
343 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
347 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
348 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
352 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
353 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
357 double hor_rotation, vert_rotation;
358 static float gamma = system_gamma;
360 // first determine the difference between our view angle and local
361 // direction to the sun
362 vert_rotation = pitch + pitch_offset;
363 hor_rotation = -(_sun_rotation + SGD_PI) - heading + heading_offset;
364 if (hor_rotation < 0 )
365 hor_rotation = fmod(hor_rotation, SGD_2PI) + SGD_2PI;
367 hor_rotation = fmod(hor_rotation, SGD_2PI);
369 // revert to unmodified values before usign them.
371 SGVec4f color = thesky->get_scene_color();
373 gamma_restore_rgb( _fog_color.data(), gamma );
374 gamma_restore_rgb( _sky_color.data(), gamma );
376 // Calculate the fog color in the direction of the sun for
377 // sunrise/sunset effects.
379 float s_red = color[0]*color[0]*color[0];
380 float s_green = color[1]*color[1]*color[1];
381 float s_blue = color[2]*color[2];
383 // interpolate beween the sunrise/sunset color and the color
384 // at the opposite direction of this effect. Take in account
385 // the current visibility.
387 float av = thesky->get_visibility();
388 if (av > 45000) av = 45000;
390 float avf = 0.87 - (45000 - av) / 83333.33;
391 float sif = 0.5 - cos(_sun_angle*2)/2;
396 float rf1 = fabs((hor_rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
397 float rf2 = avf * pow(rf1*rf1, 1/sif) * 1.0639;
398 float rf3 = 1.0 - rf2;
400 gamma = system_gamma * (0.9 - sif*avf);
402 _adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
403 _adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
404 _adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
405 gamma_correct_rgb( _adj_fog_color.data(), gamma);
407 // make sure the colors have their original value before they are being
408 // used by the rest of the program.
410 gamma_correct_rgb( _fog_color.data(), gamma );
411 gamma_correct_rgb( _sky_color.data(), gamma );
414 // update the cur_time_params structure with the current sun position
415 void FGLight::updateSunPos()
417 SGTime *t = globals->get_time_params();
418 FGViewer *v = globals->get_current_view();
420 SG_LOG( SG_EVENT, SG_DEBUG, " Updating Sun position" );
421 SG_LOG( SG_EVENT, SG_DEBUG, " Gst = " << t->getGst() );
425 fgSunPositionGST(t->getGst(), &sun_l, &sun_gd_lat);
427 set_sun_lat(sun_gd_lat);
428 SGVec3d sunpos(SGVec3d::fromGeod(SGGeod::fromRad(sun_l, sun_gd_lat)));
430 SG_LOG( SG_EVENT, SG_DEBUG, " t->cur_time = " << t->get_cur_time() );
431 SG_LOG( SG_EVENT, SG_DEBUG,
432 " Sun Geodetic lat = " << sun_gd_lat
433 << " Geodetic lat = " << sun_gd_lat );
435 // update the sun light vector
436 sun_vec() = SGVec4f(toVec3f(normalize(sunpos)), 0);
437 sun_vec_inv() = - sun_vec();
439 // calculate the sun's relative angle to local up
440 SGVec3d viewPos = v->get_view_pos();
441 SGQuatd hlOr = SGQuatd::fromLonLat(SGGeod::fromCart(viewPos));
442 SGVec3f world_up = toVec3f(hlOr.backTransform(-SGVec3d::e3()));
443 SGVec3f nsun = toVec3f(normalize(sunpos));
444 // cout << "nup = " << nup[0] << "," << nup[1] << ","
445 // << nup[2] << endl;
446 // cout << "nsun = " << nsun[0] << "," << nsun[1] << ","
447 // << nsun[2] << endl;
449 set_sun_angle( acos( dot ( world_up, nsun ) ) );
450 SG_LOG( SG_EVENT, SG_DEBUG, "sun angle relative to current location = "
451 << get_sun_angle() );
453 // calculate vector to sun's position on the earth's surface
454 SGVec3d rel_sunpos = sunpos - v->get_view_pos();
455 // vector in cartesian coordinates from current position to the
456 // postion on the earth's surface the sun is directly over
457 SGVec3f to_sun = toVec3f(rel_sunpos);
458 // printf( "Vector to sun = %.2f %.2f %.2f\n",
459 // v->to_sun[0], v->to_sun[1], v->to_sun[2]);
461 // Given a vector from the view position to the point on the
462 // earth's surface the sun is directly over, map into onto the
463 // local plane representing "horizontal".
465 // surface direction to go to head towards sun
466 SGVec3f surface_to_sun;
467 SGVec3f view_pos = toVec3f(v->get_view_pos());
468 surface_to_sun = map_vec_onto_cur_surface_plane(world_up, view_pos, to_sun);
469 surface_to_sun = normalize(surface_to_sun);
470 // cout << "(sg) Surface direction to sun is "
471 // << surface_to_sun[0] << ","
472 // << surface_to_sun[1] << ","
473 // << surface_to_sun[2] << endl;
474 // cout << "Should be close to zero = "
475 // << sgScalarProductVec3(nup, surface_to_sun) << endl;
477 // calculate the angle between surface_to_sun and
478 // v->get_surface_east(). We do this so we can sort out the
479 // acos() ambiguity. I wish I could think of a more efficient
481 SGVec3f surface_east(toVec3f(hlOr.backTransform(SGVec3d::e2())));
482 float east_dot = dot( surface_to_sun, surface_east );
483 // cout << " East dot product = " << east_dot << endl;
485 // calculate the angle between v->surface_to_sun and
486 // v->surface_south. this is how much we have to rotate the sky
487 // for it to align with the sun
488 SGVec3f surface_south(toVec3f(hlOr.backTransform(-SGVec3d::e1())));
489 float dot_ = dot( surface_to_sun, surface_south );
490 // cout << " Dot product = " << dot << endl;
493 SG_LOG( SG_ASTRO, SG_INFO,
494 "Dot product = " << dot_ << " is greater than 1.0" );
497 else if (dot_ < -1.0) {
498 SG_LOG( SG_ASTRO, SG_INFO,
499 "Dot product = " << dot_ << " is less than -1.0" );
503 if ( east_dot >= 0 ) {
504 set_sun_rotation( acos(dot_) );
506 set_sun_rotation( -acos(dot_) );
508 // cout << " Sky needs to rotate = " << angle << " rads = "
509 // << angle * SGD_RADIANS_TO_DEGREES << " degrees." << endl;