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 ),
63 _moon_vec(0, 0, 0, 0),
64 _sun_vec_inv(0, 0, 0, 0),
65 _moon_vec_inv(0, 0, 0, 0),
71 _scene_ambient(0, 0, 0, 0),
72 _scene_diffuse(0, 0, 0, 0),
73 _scene_specular(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),
93 // initialize lighting tables
94 void FGLight::init () {
95 SG_LOG( SG_EVENT, SG_INFO,
96 "Initializing Lighting interpolation tables." );
98 // build the path names of the lookup tables
99 SGPath path( globals->get_fg_root() );
101 // initialize ambient, diffuse and specular tables
102 SGPath ambient_path = path;
103 ambient_path.append( "Lighting/ambient" );
104 _ambient_tbl = new SGInterpTable( ambient_path.str() );
106 SGPath diffuse_path = path;
107 diffuse_path.append( "Lighting/diffuse" );
108 _diffuse_tbl = new SGInterpTable( diffuse_path.str() );
110 SGPath specular_path = path;
111 specular_path.append( "Lighting/specular" );
112 _specular_tbl = new SGInterpTable( specular_path.str() );
114 // initialize sky table
115 SGPath sky_path = path;
116 sky_path.append( "Lighting/sky" );
117 _sky_tbl = new SGInterpTable( sky_path.str() );
121 void FGLight::reinit () {
122 _prev_sun_angle = -9999.0;
127 delete _specular_tbl;
135 update_adj_fog_color();
138 void FGLight::bind () {
139 SGPropertyNode *prop = globals->get_props();
140 prop->tie("/sim/time/sun-angle-rad",SGRawValuePointer<double>(&_sun_angle));
141 prop->tie("/rendering/scene/ambient/red",SGRawValuePointer<float>(&_scene_ambient[0]));
142 prop->tie("/rendering/scene/ambient/green",SGRawValuePointer<float>(&_scene_ambient[1]));
143 prop->tie("/rendering/scene/ambient/blue",SGRawValuePointer<float>(&_scene_ambient[2]));
144 prop->tie("/rendering/scene/diffuse/red",SGRawValuePointer<float>(&_scene_diffuse[0]));
145 prop->tie("/rendering/scene/diffuse/green",SGRawValuePointer<float>(&_scene_diffuse[1]));
146 prop->tie("/rendering/scene/diffuse/blue",SGRawValuePointer<float>(&_scene_diffuse[2]));
147 prop->tie("/rendering/scene/specular/red",SGRawValuePointer<float>(&_scene_specular[0]));
148 prop->tie("/rendering/scene/specular/green",SGRawValuePointer<float>(&_scene_specular[1]));
149 prop->tie("/rendering/scene/specular/blue",SGRawValuePointer<float>(&_scene_specular[2]));
152 void FGLight::unbind () {
153 SGPropertyNode *prop = globals->get_props();
154 prop->untie("/sim/time/sun-angle-rad");
155 prop->untie("/rendering/scene/ambient/red");
156 prop->untie("/rendering/scene/ambient/green");
157 prop->untie("/rendering/scene/ambient/blue");
158 prop->untie("/rendering/scene/diffuse/red");
159 prop->untie("/rendering/scene/diffuse/green");
160 prop->untie("/rendering/scene/diffuse/blue");
161 prop->untie("/rendering/scene/specular/red");
162 prop->untie("/rendering/scene/specular/green");
163 prop->untie("/rendering/scene/specular/blue");
167 // update lighting parameters based on current sun position
168 void FGLight::update( double dt ) {
171 if (_dt_total >= 0.5) {
176 update_adj_fog_color();
178 if (_prev_sun_angle != _sun_angle) {
179 _prev_sun_angle = _sun_angle;
184 void FGLight::update_sky_color () {
185 // if the 4th field is 0.0, this specifies a direction ...
186 // const GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
187 const GLfloat base_sky_color[4] = { 0.31, 0.43, 0.69, 1.0 };
188 const GLfloat base_fog_color[4] = { 0.84, 0.87, 1.0, 1.0 };
190 SG_LOG( SG_EVENT, SG_DEBUG, "Updating light parameters." );
192 // calculate lighting parameters based on sun's relative angle to
194 static SGConstPropertyNode_ptr humidity = fgGetNode("/environment/relative-humidity");
195 float av = humidity->getFloatValue() * 45;
196 float visibility_log = log(av)/11.0;
197 float visibility_inv = (45000.0 - av)/45000.0;
199 float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
200 SG_LOG( SG_EVENT, SG_DEBUG, " Sun angle = " << deg );
202 float ambient = _ambient_tbl->interpolate( deg ) + visibility_inv/10;
203 float diffuse = _diffuse_tbl->interpolate( deg );
204 float specular = _specular_tbl->interpolate( deg ) * visibility_log;
205 float sky_brightness = _sky_tbl->interpolate( deg );
207 SG_LOG( SG_EVENT, SG_DEBUG,
208 " ambient = " << ambient << " diffuse = " << diffuse
209 << " specular = " << specular << " sky = " << sky_brightness );
211 // sky_brightness = 0.15; // used to force a dark sky (when testing)
213 // set fog and cloud color
214 float sqrt_sky_brightness = 1.0 - sqrt(1.0 - sky_brightness);
215 _fog_color[0] = base_fog_color[0] * sqrt_sky_brightness;
216 _fog_color[1] = base_fog_color[1] * sqrt_sky_brightness;
217 _fog_color[2] = base_fog_color[2] * sqrt_sky_brightness;
218 _fog_color[3] = base_fog_color[3];
219 gamma_correct_rgb( _fog_color.data() );
222 _sky_color[0] = base_sky_color[0] * sky_brightness;
223 _sky_color[1] = base_sky_color[1] * sky_brightness;
224 _sky_color[2] = base_sky_color[2] * sky_brightness;
225 _sky_color[3] = base_sky_color[3];
226 gamma_correct_rgb( _sky_color.data() );
228 _cloud_color[0] = base_fog_color[0] * sky_brightness;
229 _cloud_color[1] = base_fog_color[1] * sky_brightness;
230 _cloud_color[2] = base_fog_color[2] * sky_brightness;
231 _cloud_color[3] = base_fog_color[3];
233 // adjust the cloud colors for sunrise/sunset effects (darken them)
234 if (_sun_angle > 1.0) {
235 float sun2 = sqrt(_sun_angle);
236 _cloud_color[0] /= sun2;
237 _cloud_color[1] /= sun2;
238 _cloud_color[2] /= sun2;
240 gamma_correct_rgb( _cloud_color.data() );
242 _scene_ambient[0] = _fog_color[0] * ambient;
243 _scene_ambient[1] = _fog_color[1] * ambient;
244 _scene_ambient[2] = _fog_color[2] * ambient;
245 _scene_ambient[3] = 1.0;
246 gamma_correct_rgb( _scene_ambient.data() );
248 SGVec4f sun_color = thesky->get_sun_color();
249 float ndiff = (ambient + specular) / 2;
250 float idiff = 1.0 - ndiff;
251 _scene_diffuse[0] = (sun_color[0]*ndiff + _fog_color[0]*idiff) * diffuse;
252 _scene_diffuse[1] = (sun_color[1]*ndiff + _fog_color[1]*idiff) * diffuse;
253 _scene_diffuse[2] = (sun_color[2]*ndiff + _fog_color[2]*idiff) * diffuse;
254 _scene_diffuse[3] = 1.0;
255 gamma_correct_rgb( _scene_diffuse.data() );
257 _scene_specular[0] = sun_color[0] * specular;
258 _scene_specular[1] = sun_color[1] * specular;
259 _scene_specular[2] = sun_color[2] * specular;
260 _scene_specular[3] = 1.0;
261 gamma_correct_rgb( _scene_specular.data() );
265 // calculate fog color adjusted for sunrise/sunset effects
266 void FGLight::update_adj_fog_color () {
268 double pitch = globals->get_current_view()->getPitch_deg()
269 * SGD_DEGREES_TO_RADIANS;
270 double pitch_offset = globals->get_current_view()-> getPitchOffset_deg()
271 * SGD_DEGREES_TO_RADIANS;
272 double heading = globals->get_current_view()->getHeading_deg()
273 * SGD_DEGREES_TO_RADIANS;
274 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
275 * SGD_DEGREES_TO_RADIANS;
277 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
279 // set fog color (we'll try to match the sunset color in the
280 // direction we are looking
282 // Do some sanity checking ...
283 if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
284 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
288 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
289 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
293 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
294 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
298 double hor_rotation, vert_rotation;
300 // first determine the difference between our view angle and local
301 // direction to the sun
302 vert_rotation = pitch + pitch_offset;
303 hor_rotation = -(_sun_rotation + SGD_PI) - heading + heading_offset;
304 if (hor_rotation < 0 )
305 hor_rotation = fmod(hor_rotation, SGD_2PI) + SGD_2PI;
307 hor_rotation = fmod(hor_rotation, SGD_2PI);
309 // revert to unmodified values before usign them.
311 SGVec4f sun_color = thesky->get_sun_color();
313 gamma_restore_rgb( _fog_color.data() );
314 gamma_restore_rgb( _sky_color.data() );
316 // Calculate the fog color in the direction of the sun for
317 // sunrise/sunset effects.
319 float s_red = sun_color[0]*sun_color[0];
320 float s_green = sun_color[1]*sun_color[1];
321 float s_blue = sun_color[2];
323 // interpolate beween the sunrise/sunset color and the color
324 // at the opposite direction of this effect. Take in account
325 // the current visibility.
327 float av = thesky->get_visibility();
328 if (av > 45000) av = 45000;
330 float avf = 0.87 - (45000 - av) / 83333.33;
331 float sif = 0.5 - cos(_sun_angle*2)/2;
336 float rf1 = fabs((hor_rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
337 float rf2 = avf * pow(rf1*rf1, 1/sif) * 1.0639;
338 float rf3 = 1.0 - rf2;
340 _adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
341 _adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
342 _adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
343 gamma_correct_rgb( _adj_fog_color.data() );
345 // make sure the colors have their original value before they are being
346 // used by the rest of the program.
348 gamma_correct_rgb( _fog_color.data() );
349 gamma_correct_rgb( _sky_color.data() );