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>
37 #ifdef SG_MATH_EXCEPTION_CLASH
38 # define exception c_exception
41 #ifdef SG_HAVE_STD_INCLUDES
47 #include <simgear/constants.h>
48 #include <simgear/debug/logstream.hxx>
49 #include <simgear/math/interpolater.hxx>
50 #include <simgear/math/polar3d.hxx>
51 #include <simgear/misc/sg_path.hxx>
52 #include <simgear/scene/sky/sky.hxx>
53 #include <simgear/screen/colors.hxx>
55 #include <Main/main.hxx>
56 #include <Main/globals.hxx>
57 #include <Main/fg_props.hxx>
58 #include <Main/renderer.hxx>
59 #include <Main/viewer.hxx>
67 : _ambient_tbl( NULL ),
69 _specular_tbl( NULL ),
78 _moon_vec(0, 0, 0, 0),
79 _sun_vec_inv(0, 0, 0, 0),
80 _moon_vec_inv(0, 0, 0, 0),
86 _scene_ambient(0, 0, 0, 0),
87 _scene_diffuse(0, 0, 0, 0),
88 _scene_specular(0, 0, 0, 0),
89 _sky_color(0, 0, 0, 0),
90 _fog_color(0, 0, 0, 0),
91 _cloud_color(0, 0, 0, 0),
92 _adj_fog_color(0, 0, 0, 0),
93 _adj_sky_color(0, 0, 0, 0),
103 delete _specular_tbl;
108 // initialize lighting tables
109 void FGLight::init () {
110 SG_LOG( SG_EVENT, SG_INFO,
111 "Initializing Lighting interpolation tables." );
113 // build the path names of the lookup tables
114 SGPath path( globals->get_fg_root() );
116 // initialize ambient, diffuse and specular tables
117 SGPath ambient_path = path;
118 ambient_path.append( "Lighting/ambient" );
119 _ambient_tbl = new SGInterpTable( ambient_path.str() );
121 SGPath diffuse_path = path;
122 diffuse_path.append( "Lighting/diffuse" );
123 _diffuse_tbl = new SGInterpTable( diffuse_path.str() );
125 SGPath specular_path = path;
126 specular_path.append( "Lighting/specular" );
127 _specular_tbl = new SGInterpTable( specular_path.str() );
129 // initialize sky table
130 SGPath sky_path = path;
131 sky_path.append( "Lighting/sky" );
132 _sky_tbl = new SGInterpTable( sky_path.str() );
136 void FGLight::reinit () {
137 _prev_sun_angle = -9999.0;
142 delete _specular_tbl;
150 update_adj_fog_color();
153 void FGLight::bind () {
154 SGPropertyNode *prop = globals->get_props();
155 prop->tie("/sim/time/sun-angle-rad",SGRawValuePointer<double>(&_sun_angle));
156 prop->tie("/rendering/scene/ambient/red",SGRawValuePointer<float>(&_scene_ambient[0]));
157 prop->tie("/rendering/scene/ambient/green",SGRawValuePointer<float>(&_scene_ambient[1]));
158 prop->tie("/rendering/scene/ambient/blue",SGRawValuePointer<float>(&_scene_ambient[2]));
159 prop->tie("/rendering/scene/diffuse/red",SGRawValuePointer<float>(&_scene_diffuse[0]));
160 prop->tie("/rendering/scene/diffuse/green",SGRawValuePointer<float>(&_scene_diffuse[1]));
161 prop->tie("/rendering/scene/diffuse/blue",SGRawValuePointer<float>(&_scene_diffuse[2]));
162 prop->tie("/rendering/scene/specular/red",SGRawValuePointer<float>(&_scene_specular[0]));
163 prop->tie("/rendering/scene/specular/green",SGRawValuePointer<float>(&_scene_specular[1]));
164 prop->tie("/rendering/scene/specular/blue",SGRawValuePointer<float>(&_scene_specular[2]));
167 void FGLight::unbind () {
168 SGPropertyNode *prop = globals->get_props();
169 prop->untie("/sim/time/sun-angle-rad");
170 prop->untie("/rendering/scene/ambient/red");
171 prop->untie("/rendering/scene/ambient/green");
172 prop->untie("/rendering/scene/ambient/blue");
173 prop->untie("/rendering/scene/diffuse/red");
174 prop->untie("/rendering/scene/diffuse/green");
175 prop->untie("/rendering/scene/diffuse/blue");
176 prop->untie("/rendering/scene/specular/red");
177 prop->untie("/rendering/scene/specular/green");
178 prop->untie("/rendering/scene/specular/blue");
182 // update lighting parameters based on current sun position
183 void FGLight::update( double dt ) {
186 if (_dt_total >= 0.5) {
191 update_adj_fog_color();
193 if (_prev_sun_angle != _sun_angle) {
194 _prev_sun_angle = _sun_angle;
199 void FGLight::update_sky_color () {
200 // if the 4th field is 0.0, this specifies a direction ...
201 // const GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
202 const GLfloat base_sky_color[4] = { 0.31, 0.43, 0.69, 1.0 };
203 const GLfloat base_fog_color[4] = { 0.84, 0.87, 1.0, 1.0 };
205 SG_LOG( SG_EVENT, SG_DEBUG, "Updating light parameters." );
207 // calculate lighting parameters based on sun's relative angle to
210 float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
211 SG_LOG( SG_EVENT, SG_DEBUG, " Sun angle = " << deg );
213 float ambient = _ambient_tbl->interpolate( deg );
214 float diffuse = _diffuse_tbl->interpolate( deg );
215 float specular = _specular_tbl->interpolate( deg );
216 float sky_brightness = _sky_tbl->interpolate( deg );
218 SG_LOG( SG_EVENT, SG_DEBUG,
219 " ambient = " << ambient << " diffuse = " << diffuse
220 << " specular = " << specular << " sky = " << sky_brightness );
222 // sky_brightness = 0.15; // used to force a dark sky (when testing)
224 // if ( ambient < 0.02 ) { ambient = 0.02; }
225 // if ( diffuse < 0.0 ) { diffuse = 0.0; }
226 // if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
229 _sky_color[0] = base_sky_color[0] * sky_brightness;
230 _sky_color[1] = base_sky_color[1] * sky_brightness;
231 _sky_color[2] = base_sky_color[2] * sky_brightness;
232 _sky_color[3] = base_sky_color[3];
233 gamma_correct_rgb( _sky_color.data() );
235 // set cloud and fog color
236 _cloud_color[0] = _fog_color[0] = base_fog_color[0] * sky_brightness;
237 _cloud_color[1] = _fog_color[1] = base_fog_color[1] * sky_brightness;
238 _cloud_color[2] = _fog_color[2] = base_fog_color[2] * sky_brightness;
239 _cloud_color[3] = _fog_color[3] = base_fog_color[3];
240 gamma_correct_rgb( _fog_color.data() );
242 // adjust the cloud colors for sunrise/sunset effects (darken them)
243 if (_sun_angle > 1.0) {
244 float sun2 = sqrt(_sun_angle);
245 _cloud_color[0] /= sun2;
246 _cloud_color[1] /= sun2;
247 _cloud_color[2] /= sun2;
249 gamma_correct_rgb( _cloud_color.data() );
251 SGVec4f sun_color = thesky->get_sun_color();
253 _scene_ambient[0] = ((sun_color[0]*0.25 + _cloud_color[0]*0.75) + ambient) / 2;
254 _scene_ambient[1] = ((sun_color[1]*0.25 + _cloud_color[1]*0.75) + ambient) / 2;
255 _scene_ambient[2] = ((sun_color[2]*0.25 + _cloud_color[2]*0.75) + ambient) / 2;
256 _scene_ambient[3] = 1.0;
258 _scene_diffuse[0] = (sun_color[0]*0.25 + _fog_color[0]*0.75) * diffuse;
259 _scene_diffuse[1] = (sun_color[1]*0.25 + _fog_color[1]*0.75) * diffuse;
260 _scene_diffuse[2] = (sun_color[2]*0.25 + _fog_color[2]*0.75) * diffuse;
261 _scene_diffuse[3] = 1.0;
263 _scene_specular[0] = sun_color[0] * specular;
264 _scene_specular[1] = sun_color[1] * specular;
265 _scene_specular[2] = sun_color[2] * specular;
266 _scene_specular[3] = 1.0;
270 // calculate fog color adjusted for sunrise/sunset effects
271 void FGLight::update_adj_fog_color () {
273 double heading = globals->get_current_view()->getHeading_deg()
274 * SGD_DEGREES_TO_RADIANS;
275 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
276 * SGD_DEGREES_TO_RADIANS;
278 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
280 // set fog color (we'll try to match the sunset color in the
281 // direction we are looking
283 // Do some sanity checking ...
284 if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
285 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
289 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
290 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
294 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
295 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
301 // first determine the difference between our view angle and local
302 // direction to the sun
303 rotation = -(_sun_rotation + SGD_PI) - heading + heading_offset;
304 while ( rotation < 0 ) {
307 while ( rotation > SGD_2PI ) {
311 // revert to unmodified values before usign them.
313 SGVec4f sun_color = thesky->get_sun_color();
315 gamma_restore_rgb( _fog_color.data() );
317 // Calculate the fog color in the direction of the sun for
318 // sunrise/sunset effects.
320 float s_red = (_fog_color[0] + 2 * sun_color[0]*sun_color[0]) / 3;
321 float s_green = (_fog_color[1] + 2 * sun_color[1]*sun_color[1]) / 3;
322 float s_blue = (_fog_color[2] + 2 * sun_color[2]) / 3;
324 // interpolate beween the sunrise/sunset color and the color
325 // at the opposite direction of this effect. Take in account
326 // the current visibility.
328 float av = thesky->get_visibility();
332 float avf = 0.87 - (45000 - av) / 83333.33;
333 float sif = 0.5 - cos(_sun_angle*2)/2;
338 float rf1 = fabs((rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
339 float rf2 = avf * pow(rf1 * rf1, 1/sif);
340 float rf3 = 0.94 - rf2;
342 _adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
343 _adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
344 _adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
345 gamma_correct_rgb( _adj_fog_color.data() );
347 // make sure the colors have their original value before they are being
348 // used by the rest of the program.
350 gamma_correct_rgb( _fog_color.data() );