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
195 float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
196 SG_LOG( SG_EVENT, SG_DEBUG, " Sun angle = " << deg );
198 float ambient = _ambient_tbl->interpolate( deg );
199 float diffuse = _diffuse_tbl->interpolate( deg );
200 float specular = _specular_tbl->interpolate( deg );
201 float sky_brightness = _sky_tbl->interpolate( deg );
203 SG_LOG( SG_EVENT, SG_DEBUG,
204 " ambient = " << ambient << " diffuse = " << diffuse
205 << " specular = " << specular << " sky = " << sky_brightness );
207 // sky_brightness = 0.15; // used to force a dark sky (when testing)
209 // if ( ambient < 0.02 ) { ambient = 0.02; }
210 // if ( diffuse < 0.0 ) { diffuse = 0.0; }
211 // if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
214 _sky_color[0] = base_sky_color[0] * sky_brightness;
215 _sky_color[1] = base_sky_color[1] * sky_brightness;
216 _sky_color[2] = base_sky_color[2] * sky_brightness;
217 _sky_color[3] = base_sky_color[3];
218 gamma_correct_rgb( _sky_color.data() );
220 // set cloud and fog color
221 _cloud_color[0] = _fog_color[0] = base_fog_color[0] * sky_brightness;
222 _cloud_color[1] = _fog_color[1] = base_fog_color[1] * sky_brightness;
223 _cloud_color[2] = _fog_color[2] = base_fog_color[2] * sky_brightness;
224 _cloud_color[3] = _fog_color[3] = base_fog_color[3];
225 gamma_correct_rgb( _fog_color.data() );
227 // adjust the cloud colors for sunrise/sunset effects (darken them)
228 if (_sun_angle > 1.0) {
229 float sun2 = sqrt(_sun_angle);
230 _cloud_color[0] /= sun2;
231 _cloud_color[1] /= sun2;
232 _cloud_color[2] /= sun2;
234 gamma_correct_rgb( _cloud_color.data() );
236 SGVec4f sun_color = thesky->get_sun_color();
238 _scene_ambient[0] = ((sun_color[0]*0.25 + _cloud_color[0]*0.75) + ambient) / 2;
239 _scene_ambient[1] = ((sun_color[1]*0.25 + _cloud_color[1]*0.75) + ambient) / 2;
240 _scene_ambient[2] = ((sun_color[2]*0.25 + _cloud_color[2]*0.75) + ambient) / 2;
241 _scene_ambient[3] = 1.0;
243 _scene_diffuse[0] = (sun_color[0]*0.25 + _fog_color[0]*0.75) * diffuse;
244 _scene_diffuse[1] = (sun_color[1]*0.25 + _fog_color[1]*0.75) * diffuse;
245 _scene_diffuse[2] = (sun_color[2]*0.25 + _fog_color[2]*0.75) * diffuse;
246 _scene_diffuse[3] = 1.0;
248 _scene_specular[0] = sun_color[0] * specular;
249 _scene_specular[1] = sun_color[1] * specular;
250 _scene_specular[2] = sun_color[2] * specular;
251 _scene_specular[3] = 1.0;
255 // calculate fog color adjusted for sunrise/sunset effects
256 void FGLight::update_adj_fog_color () {
258 double heading = globals->get_current_view()->getHeading_deg()
259 * SGD_DEGREES_TO_RADIANS;
260 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
261 * SGD_DEGREES_TO_RADIANS;
263 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
265 // set fog color (we'll try to match the sunset color in the
266 // direction we are looking
268 // Do some sanity checking ...
269 if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
270 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
274 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
275 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
279 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
280 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
286 // first determine the difference between our view angle and local
287 // direction to the sun
288 rotation = -(_sun_rotation + SGD_PI) - heading + heading_offset;
289 while ( rotation < 0 ) {
292 while ( rotation > SGD_2PI ) {
296 // revert to unmodified values before usign them.
298 SGVec4f sun_color = thesky->get_sun_color();
300 gamma_restore_rgb( _fog_color.data() );
302 // Calculate the fog color in the direction of the sun for
303 // sunrise/sunset effects.
305 float s_red = (_fog_color[0] + 2 * sun_color[0]*sun_color[0]) / 3;
306 float s_green = (_fog_color[1] + 2 * sun_color[1]*sun_color[1]) / 3;
307 float s_blue = (_fog_color[2] + 2 * sun_color[2]) / 3;
309 // interpolate beween the sunrise/sunset color and the color
310 // at the opposite direction of this effect. Take in account
311 // the current visibility.
313 float av = thesky->get_visibility();
317 float avf = 0.87 - (45000 - av) / 83333.33;
318 float sif = 0.5 - cos(_sun_angle*2)/2;
323 float rf1 = fabs((rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
324 float rf2 = avf * pow(rf1 * rf1, 1/sif);
325 float rf3 = 0.94 - rf2;
327 _adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
328 _adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
329 _adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
330 gamma_correct_rgb( _adj_fog_color.data() );
332 // make sure the colors have their original value before they are being
333 // used by the rest of the program.
335 gamma_correct_rgb( _fog_color.data() );