2 // light.cxx -- lighting routines
4 // Written by Curtis Olson, started April 1998.
6 // Copyright (C) 1998 Curtis L. Olson - curt@me.umn.edu
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., 675 Mass Ave, Cambridge, MA 02139, USA.
35 #include <simgear/compiler.h>
37 #ifdef SG_MATH_EXCEPTION_CLASH
38 # define exception c_exception
41 #ifdef SG_HAVE_STD_INCLUDES
50 #include <simgear/constants.h>
51 #include <simgear/debug/logstream.hxx>
52 #include <simgear/math/interpolater.hxx>
53 #include <simgear/math/polar3d.hxx>
54 #include <simgear/misc/sg_path.hxx>
55 #include <simgear/screen/colors.hxx>
56 #include <simgear/sky/sky.hxx>
58 #include <Main/globals.hxx>
59 #include <Main/viewer.hxx>
64 extern SGSky *thesky; // FIXME: from main.cxx
65 fgLIGHT cur_light_params;
69 fgLIGHT::fgLIGHT( void ) {
73 // initialize lighting tables
74 void fgLIGHT::Init( void ) {
75 SG_LOG( SG_EVENT, SG_INFO,
76 "Initializing Lighting interpolation tables." );
78 // build the path name to the ambient lookup table
79 SGPath path( globals->get_fg_root() );
80 SGPath ambient = path;
81 ambient.append( "Lighting/ambient" );
82 SGPath diffuse = path;
83 diffuse.append( "Lighting/diffuse" );
84 SGPath specular = path;
85 specular.append( "Lighting/specular" );
87 sky.append( "Lighting/sky" );
89 // initialize ambient table
90 ambient_tbl = new SGInterpTable( ambient.str() );
92 // initialize diffuse table
93 diffuse_tbl = new SGInterpTable( diffuse.str() );
95 // initialize diffuse table
96 specular_tbl = new SGInterpTable( specular.str() );
98 // initialize sky table
99 sky_tbl = new SGInterpTable( sky.str() );
103 // update lighting parameters based on current sun position
104 void fgLIGHT::Update( void ) {
105 // if the 4th field is 0.0, this specifies a direction ...
106 GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
108 GLfloat base_sky_color[4] = { 0.39, 0.50, 0.74, 1.0 };
110 GLfloat base_fog_color[4] = { 0.84, 0.87, 1.0, 1.0 };
111 float deg, ambient, diffuse, specular, sky_brightness;
113 SG_LOG( SG_EVENT, SG_INFO, "Updating light parameters." );
115 // calculate lighting parameters based on sun's relative angle to
118 deg = sun_angle * SGD_RADIANS_TO_DEGREES;
119 SG_LOG( SG_EVENT, SG_INFO, " Sun angle = " << deg );
121 ambient = ambient_tbl->interpolate( deg );
122 diffuse = diffuse_tbl->interpolate( deg );
123 specular = specular_tbl->interpolate( deg );
124 sky_brightness = sky_tbl->interpolate( deg );
126 SG_LOG( SG_EVENT, SG_INFO,
127 " ambient = " << ambient << " diffuse = " << diffuse
128 << " specular = " << specular << " sky = " << sky_brightness );
130 // sky_brightness = 0.15; // used to force a dark sky (when testing)
132 // if ( ambient < 0.02 ) { ambient = 0.02; }
133 // if ( diffuse < 0.0 ) { diffuse = 0.0; }
134 // if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
136 gamma_correct_c( &ambient );
137 scene_ambient[0] = white[0] * ambient;
138 scene_ambient[1] = white[1] * ambient;
139 scene_ambient[2] = white[2] * ambient;
140 scene_ambient[3] = 1.0;
142 gamma_correct_c( &diffuse );
143 scene_diffuse[0] = white[0] * diffuse;
144 scene_diffuse[1] = white[1] * diffuse;
145 scene_diffuse[2] = white[2] * diffuse;
146 scene_diffuse[3] = 1.0;
148 gamma_correct_c( &specular );
149 scene_specular[0] = white[0] * specular;
150 scene_specular[1] = white[1] * specular;
151 scene_specular[2] = white[2] * specular;
152 scene_specular[3] = 1.0;
155 sky_color[0] = base_sky_color[0] * sky_brightness;
156 sky_color[1] = base_sky_color[1] * sky_brightness;
157 sky_color[2] = base_sky_color[2] * sky_brightness;
158 sky_color[3] = base_sky_color[3];
159 gamma_correct_rgb( sky_color );
161 // set cloud and fog color
162 cloud_color[0] = fog_color[0] = base_fog_color[0] * sky_brightness;
163 cloud_color[1] = fog_color[1] = base_fog_color[1] * sky_brightness;
164 cloud_color[2] = fog_color[2] = base_fog_color[2] * sky_brightness;
165 cloud_color[3] = fog_color[3] = base_fog_color[3];
166 gamma_correct_rgb( fog_color );
168 // adjust the cloud colors for sunrise/sunset effects (darken them)
169 if (sun_angle > 1.0) {
170 float sun2 = pow(sun_angle, 0.5);
171 cloud_color[0] /= sun2;
172 cloud_color[1] /= sun2;
173 cloud_color[2] /= sun2;
175 gamma_correct_rgb( cloud_color );
179 // calculate fog color adjusted for sunrise/sunset effects
180 void fgLIGHT::UpdateAdjFog( void ) {
182 double heading = globals->get_current_view()->getHeading_deg()
183 * SGD_DEGREES_TO_RADIANS;
184 double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
185 * SGD_DEGREES_TO_RADIANS;
187 SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
189 // set fog color (we'll try to match the sunset color in the
190 // direction we are looking
192 // Do some sanity checking ...
193 if ( sun_rotation < -2.0 * SGD_2PI || sun_rotation > 2.0 * SGD_2PI ) {
194 SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << sun_rotation );
198 if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
199 SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
203 if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
204 SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
210 // first determine the difference between our view angle and local
211 // direction to the sun
212 rotation = -(sun_rotation + SGD_PI) - heading + heading_offset;
213 while ( rotation < 0 ) {
216 while ( rotation > SGD_2PI ) {
220 #ifdef USE_OLD_SUNSET_CODE
222 double sun_angle_deg, param1[3], param2[3];
224 rotation *= SGD_RADIANS_TO_DEGREES;
225 // fgPrintf( SG_EVENT, SG_INFO,
226 // " View to sun difference in degrees = %.2f\n", rotation);
228 // next check if we are in a sunset/sunrise situation
229 sun_angle_deg = sun_angle * SGD_RADIANS_TO_DEGREES;
230 if ( (sun_angle_deg > 80.0) && (sun_angle_deg < 100.0) ) {
232 param1[0] = (10.0 - fabs(90.0 - sun_angle_deg)) / 20.0;
233 param1[1] = (10.0 - fabs(90.0 - sun_angle_deg)) / 40.0;
234 param1[2] = (10.0 - fabs(90.0 - sun_angle_deg)) / 30.0;
235 // param2[2] = -(10.0 - fabs(90.0 - sun_angle)) / 30.0;
237 param1[0] = param1[1] = param1[2] = 0.0;
240 if ( rotation - 180.0 <= 0.0 ) {
241 param2[0] = param1[0] * (180.0 - rotation) / 180.0;
242 param2[1] = param1[1] * (180.0 - rotation) / 180.0;
243 param2[2] = param1[2] * (180.0 - rotation) / 180.0;
244 // printf("param1[0] = %.2f param2[0] = %.2f\n", param1[0], param2[0]);
246 param2[0] = param1[0] * (rotation - 180.0) / 180.0;
247 param2[1] = param1[1] * (rotation - 180.0) / 180.0;
248 param2[2] = param1[2] * (rotation - 180.0) / 180.0;
249 // printf("param1[0] = %.2f param2[0] = %.2f\n", param1[0], param2[0]);
252 adj_fog_color[0] = fog_color[0] + param2[0];
253 if ( adj_fog_color[0] > 1.0 ) { adj_fog_color[0] = 1.0; }
255 adj_fog_color[1] = fog_color[1] + param2[1];
256 if ( adj_fog_color[1] > 1.0 ) { adj_fog_color[1] = 1.0; }
258 adj_fog_color[2] = fog_color[2] + param2[2];
259 if ( adj_fog_color[2] > 1.0 ) { adj_fog_color[2] = 1.0; }
261 adj_fog_color[3] = fog_color[3];
265 // revert to unmodified values before usign them.
267 float *sun_color = thesky->get_sun_color();
269 gamma_restore_c( sun_color );
270 gamma_restore_rgb( fog_color );
271 gamma_restore_rgb( cloud_color );
273 // Calculate the fog color in the direction of the sun for
274 // sunrise/sunset effects.
276 float s_red = (fog_color[0] + 2 * pow(sun_color[0], 2)) / 3;
277 float s_green = (fog_color[1] + 2 * pow(sun_color[1], 2)) / 3;
278 float s_blue = (fog_color[2] + 2 * sun_color[2]) / 3;
280 // interpolate beween the sunrise/sunset color and the color
281 // at the opposite direction of this effect.
283 float sif = 0.5 - cos(sun_angle*2)/2;
284 float rf1 = fabs((rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
285 float rf2 = 0.87 * pow(rf1 * rf1, 1/sif);
286 float rf3 = 1.0 - rf2;
288 adj_fog_color[0] = rf3 * fog_color[0] + rf2 * s_red;
289 adj_fog_color[1] = rf3 * fog_color[1] + rf2 * s_green;
290 adj_fog_color[2] = rf3 * fog_color[2] + rf2 * s_blue;
291 gamma_correct_rgb( adj_fog_color );
293 // make sure the colors have their original value before they are being
294 // used by the rest of the program.
296 gamma_correct_c( sun_color );
297 gamma_correct_rgb( fog_color );
298 gamma_correct_rgb( cloud_color );
304 fgLIGHT::~fgLIGHT( void ) {