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.
33 #include <simgear/compiler.h>
39 #include <simgear/constants.h>
40 #include <simgear/debug/logstream.hxx>
41 #include <simgear/math/interpolater.hxx>
42 #include <simgear/misc/sg_path.hxx>
43 #include <simgear/scene/sky/sky.hxx>
44 #include <simgear/screen/colors.hxx>
46 #include <Main/main.hxx>
47 #include <Main/globals.hxx>
48 #include <Main/fg_props.hxx>
49 #include <Main/renderer.hxx>
50 #include <Main/viewer.hxx>
58 : _ambient_tbl( NULL ),
60 _specular_tbl( NULL ),
69 _moon_vec(0, 0, 0, 0),
70 _sun_vec_inv(0, 0, 0, 0),
71 _moon_vec_inv(0, 0, 0, 0),
77 _scene_ambient(0, 0, 0, 0),
78 _scene_diffuse(0, 0, 0, 0),
79 _scene_specular(0, 0, 0, 0),
80 _sky_color(0, 0, 0, 0),
81 _fog_color(0, 0, 0, 0),
82 _cloud_color(0, 0, 0, 0),
83 _adj_fog_color(0, 0, 0, 0),
84 _adj_sky_color(0, 0, 0, 0),
99 // initialize lighting tables
100 void FGLight::init () {
101 SG_LOG( SG_EVENT, SG_INFO,
102 "Initializing Lighting interpolation tables." );
104 // build the path names of the lookup tables
105 SGPath path( globals->get_fg_root() );
107 // initialize ambient, diffuse and specular tables
108 SGPath ambient_path = path;
109 ambient_path.append( "Lighting/ambient" );
110 _ambient_tbl = new SGInterpTable( ambient_path.str() );
112 SGPath diffuse_path = path;
113 diffuse_path.append( "Lighting/diffuse" );
114 _diffuse_tbl = new SGInterpTable( diffuse_path.str() );
116 SGPath specular_path = path;
117 specular_path.append( "Lighting/specular" );
118 _specular_tbl = new SGInterpTable( specular_path.str() );
120 // initialize sky table
121 SGPath sky_path = path;
122 sky_path.append( "Lighting/sky" );
123 _sky_tbl = new SGInterpTable( sky_path.str() );
127 void FGLight::reinit () {
128 _prev_sun_angle = -9999.0;
133 delete _specular_tbl;
141 update_adj_fog_color();
144 void FGLight::bind () {
145 SGPropertyNode *prop = globals->get_props();
146 prop->tie("/sim/time/sun-angle-rad",SGRawValuePointer<double>(&_sun_angle));
147 prop->tie("/rendering/scene/ambient/red",SGRawValuePointer<float>(&_scene_ambient[0]));
148 prop->tie("/rendering/scene/ambient/green",SGRawValuePointer<float>(&_scene_ambient[1]));
149 prop->tie("/rendering/scene/ambient/blue",SGRawValuePointer<float>(&_scene_ambient[2]));
150 prop->tie("/rendering/scene/diffuse/red",SGRawValuePointer<float>(&_scene_diffuse[0]));
151 prop->tie("/rendering/scene/diffuse/green",SGRawValuePointer<float>(&_scene_diffuse[1]));
152 prop->tie("/rendering/scene/diffuse/blue",SGRawValuePointer<float>(&_scene_diffuse[2]));
153 prop->tie("/rendering/scene/specular/red",SGRawValuePointer<float>(&_scene_specular[0]));
154 prop->tie("/rendering/scene/specular/green",SGRawValuePointer<float>(&_scene_specular[1]));
155 prop->tie("/rendering/scene/specular/blue",SGRawValuePointer<float>(&_scene_specular[2]));
158 void FGLight::unbind () {
159 SGPropertyNode *prop = globals->get_props();
160 prop->untie("/sim/time/sun-angle-rad");
161 prop->untie("/rendering/scene/ambient/red");
162 prop->untie("/rendering/scene/ambient/green");
163 prop->untie("/rendering/scene/ambient/blue");
164 prop->untie("/rendering/scene/diffuse/red");
165 prop->untie("/rendering/scene/diffuse/green");
166 prop->untie("/rendering/scene/diffuse/blue");
167 prop->untie("/rendering/scene/specular/red");
168 prop->untie("/rendering/scene/specular/green");
169 prop->untie("/rendering/scene/specular/blue");
173 // update lighting parameters based on current sun position
174 void FGLight::update( double dt ) {
177 if (_dt_total >= 0.5) {
182 update_adj_fog_color();
184 if (_prev_sun_angle != _sun_angle) {
185 _prev_sun_angle = _sun_angle;
190 void FGLight::update_sky_color () {
191 // if the 4th field is 0.0, this specifies a direction ...
192 // const GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
193 const GLfloat base_sky_color[4] = { 0.31, 0.43, 0.69, 1.0 };
194 const GLfloat base_fog_color[4] = { 0.84, 0.87, 1.0, 1.0 };
196 SG_LOG( SG_EVENT, SG_DEBUG, "Updating light parameters." );
198 // calculate lighting parameters based on sun's relative angle to
201 float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
202 SG_LOG( SG_EVENT, SG_DEBUG, " Sun angle = " << deg );
204 float ambient = _ambient_tbl->interpolate( deg );
205 float diffuse = _diffuse_tbl->interpolate( deg );
206 float specular = _specular_tbl->interpolate( deg );
207 float sky_brightness = _sky_tbl->interpolate( deg );
209 SG_LOG( SG_EVENT, SG_DEBUG,
210 " ambient = " << ambient << " diffuse = " << diffuse
211 << " specular = " << specular << " sky = " << sky_brightness );
213 // sky_brightness = 0.15; // used to force a dark sky (when testing)
215 // if ( ambient < 0.02 ) { ambient = 0.02; }
216 // if ( diffuse < 0.0 ) { diffuse = 0.0; }
217 // if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
220 _sky_color[0] = base_sky_color[0] * sky_brightness;
221 _sky_color[1] = base_sky_color[1] * sky_brightness;
222 _sky_color[2] = base_sky_color[2] * sky_brightness;
223 _sky_color[3] = base_sky_color[3];
224 gamma_correct_rgb( _sky_color.data() );
226 // set cloud and fog color
227 _cloud_color[0] = _fog_color[0] = base_fog_color[0] * sky_brightness;
228 _cloud_color[1] = _fog_color[1] = base_fog_color[1] * sky_brightness;
229 _cloud_color[2] = _fog_color[2] = base_fog_color[2] * sky_brightness;
230 _cloud_color[3] = _fog_color[3] = base_fog_color[3];
231 gamma_correct_rgb( _fog_color.data() );
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 SGVec4f sun_color = thesky->get_sun_color();
244 _scene_ambient[0] = ((sun_color[0]*0.25 + _cloud_color[0]*0.75) + ambient) / 2;
245 _scene_ambient[1] = ((sun_color[1]*0.25 + _cloud_color[1]*0.75) + ambient) / 2;
246 _scene_ambient[2] = ((sun_color[2]*0.25 + _cloud_color[2]*0.75) + ambient) / 2;
247 _scene_ambient[3] = 1.0;
249 _scene_diffuse[0] = (sun_color[0]*0.25 + _fog_color[0]*0.75) * diffuse;
250 _scene_diffuse[1] = (sun_color[1]*0.25 + _fog_color[1]*0.75) * diffuse;
251 _scene_diffuse[2] = (sun_color[2]*0.25 + _fog_color[2]*0.75) * diffuse;
252 _scene_diffuse[3] = 1.0;
254 _scene_specular[0] = sun_color[0] * specular;
255 _scene_specular[1] = sun_color[1] * specular;
256 _scene_specular[2] = sun_color[2] * specular;
257 _scene_specular[3] = 1.0;
261 // calculate fog color adjusted for sunrise/sunset effects
262 void FGLight::update_adj_fog_color () {
264 double heading = globals->get_current_view()->getHeading_deg()
265 * SGD_DEGREES_TO_RADIANS;
266 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
267 * SGD_DEGREES_TO_RADIANS;
269 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
271 // set fog color (we'll try to match the sunset color in the
272 // direction we are looking
274 // Do some sanity checking ...
275 if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
276 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
280 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
281 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
285 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
286 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
292 // first determine the difference between our view angle and local
293 // direction to the sun
294 rotation = -(_sun_rotation + SGD_PI) - heading + heading_offset;
295 while ( rotation < 0 ) {
298 while ( rotation > SGD_2PI ) {
302 // revert to unmodified values before usign them.
304 SGVec4f sun_color = thesky->get_sun_color();
306 gamma_restore_rgb( _fog_color.data() );
308 // Calculate the fog color in the direction of the sun for
309 // sunrise/sunset effects.
311 float s_red = (_fog_color[0] + 2 * sun_color[0]*sun_color[0]) / 3;
312 float s_green = (_fog_color[1] + 2 * sun_color[1]*sun_color[1]) / 3;
313 float s_blue = (_fog_color[2] + 2 * sun_color[2]) / 3;
315 // interpolate beween the sunrise/sunset color and the color
316 // at the opposite direction of this effect. Take in account
317 // the current visibility.
319 float av = thesky->get_visibility();
323 float avf = 0.87 - (45000 - av) / 83333.33;
324 float sif = 0.5 - cos(_sun_angle*2)/2;
329 float rf1 = fabs((rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
330 float rf2 = avf * pow(rf1 * rf1, 1/sif);
331 float rf3 = 0.94 - rf2;
333 _adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
334 _adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
335 _adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
336 gamma_correct_rgb( _adj_fog_color.data() );
338 // make sure the colors have their original value before they are being
339 // used by the rest of the program.
341 gamma_correct_rgb( _fog_color.data() );