1 /**************************************************************************
2 * sky.c -- model sky with an upside down "bowl"
4 * Written by Curtis Olson, started December 1997.
6 * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
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.
23 * (Log is kept at end of this file)
24 **************************************************************************/
41 #include <Astro/sky.h>
43 #include <Time/event.h>
44 #include <Time/fg_time.h>
46 #include <Aircraft/aircraft.h>
47 #include <Flight/flight.h>
48 #include <Include/fg_constants.h>
49 #include <Main/views.h>
50 #include <Math/fg_random.h>
53 #include <Include/general.h>
56 /* in meters of course */
57 #define CENTER_ELEV 25000.0
59 #define INNER_RADIUS 50000.0
60 #define INNER_ELEV 20000.0
62 #define MIDDLE_RADIUS 70000.0
63 #define MIDDLE_ELEV 8000.0
65 #define OUTER_RADIUS 80000.0
66 #define OUTER_ELEV 0.0
68 #define BOTTOM_RADIUS 50000.0
69 #define BOTTOM_ELEV -2000.0
72 static float inner_vertex[12][3];
73 static float middle_vertex[12][3];
74 static float outer_vertex[12][3];
75 static float bottom_vertex[12][3];
77 static float inner_color[12][4];
78 static float middle_color[12][4];
79 static float outer_color[12][4];
82 /* Calculate the sky structure vertices */
83 void fgSkyVerticesInit( void ) {
87 printf(" Generating the sky dome vertices.\n");
89 for ( i = 0; i < 12; i++ ) {
90 theta = (i * 30.0) * DEG_TO_RAD;
92 inner_vertex[i][0] = cos(theta) * INNER_RADIUS;
93 inner_vertex[i][1] = sin(theta) * INNER_RADIUS;
94 inner_vertex[i][2] = INNER_ELEV;
96 /* printf(" %.2f %.2f\n", cos(theta) * INNER_RADIUS,
97 sin(theta) * INNER_RADIUS); */
99 middle_vertex[i][0] = cos((double)theta) * MIDDLE_RADIUS;
100 middle_vertex[i][1] = sin((double)theta) * MIDDLE_RADIUS;
101 middle_vertex[i][2] = MIDDLE_ELEV;
103 outer_vertex[i][0] = cos((double)theta) * OUTER_RADIUS;
104 outer_vertex[i][1] = sin((double)theta) * OUTER_RADIUS;
105 outer_vertex[i][2] = OUTER_ELEV;
107 bottom_vertex[i][0] = cos((double)theta) * BOTTOM_RADIUS;
108 bottom_vertex[i][1] = sin((double)theta) * BOTTOM_RADIUS;
109 bottom_vertex[i][2] = BOTTOM_ELEV;
114 /* (Re)calculate the sky colors at each vertex */
115 void fgSkyColorsInit( void ) {
117 float sun_angle, diff;
118 float outer_param[3], outer_amt[3], outer_diff[3];
119 float middle_param[3], middle_amt[3], middle_diff[3];
122 l = &cur_light_params;
124 printf(" Generating the sky colors for each vertex.\n");
126 /* setup for the possibility of sunset effects */
127 sun_angle = l->sun_angle * RAD_TO_DEG;
128 printf(" Sun angle in degrees = %.2f\n", sun_angle);
130 if ( (sun_angle > 80.0) && (sun_angle < 100.0) ) {
132 outer_param[0] = (10.0 - fabs(90.0 - sun_angle)) / 25.0;
133 outer_param[1] = (10.0 - fabs(90.0 - sun_angle)) / 35.0;
134 outer_param[2] = 0.0;
136 middle_param[0] = (10.0 - fabs(90.0 - sun_angle)) / 20.0;
137 middle_param[1] = (10.0 - fabs(90.0 - sun_angle)) / 40.0;
138 middle_param[2] = 0.0;
140 outer_diff[0] = outer_param[0] / 6.0;
141 outer_diff[1] = outer_param[1] / 6.0;
142 outer_diff[2] = outer_param[2] / 6.0;
144 middle_diff[0] = middle_param[0] / 6.0;
145 middle_diff[1] = middle_param[1] / 6.0;
146 middle_diff[2] = middle_param[2] / 6.0;
148 outer_param[0] = outer_param[1] = outer_param[2] = 0.0;
149 middle_param[0] = middle_param[1] = middle_param[2] = 0.0;
151 outer_diff[0] = outer_diff[1] = outer_diff[2] = 0.0;
152 middle_diff[0] = middle_diff[1] = middle_diff[2] = 0.0;
154 /* printf(" outer_red_param = %.2f outer_red_diff = %.2f\n",
155 outer_red_param, outer_red_diff); */
157 /* calculate transition colors between sky and fog */
158 for ( j = 0; j < 3; j++ ) {
159 outer_amt[j] = outer_param[j];
160 middle_amt[j] = middle_param[j];
163 for ( i = 0; i < 6; i++ ) {
164 for ( j = 0; j < 3; j++ ) {
165 diff = l->sky_color[j] - l->fog_color[j];
167 inner_color[i][j] = l->sky_color[j] - diff * 0.3;
168 middle_color[i][j] = l->sky_color[j] - diff * 0.9 + middle_amt[j];
169 outer_color[i][j] = l->fog_color[j] + outer_amt[j];
171 if ( middle_color[i][j] > 1.00 ) { middle_color[i][j] = 1.00; }
172 if ( middle_color[i][j] < 0.10 ) { middle_color[i][j] = 0.10; }
173 if ( outer_color[i][j] > 1.00 ) { outer_color[i][j] = 1.00; }
174 if ( outer_color[i][j] < 0.10 ) { outer_color[i][j] = 0.10; }
176 inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
179 for ( j = 0; j < 3; j++ ) {
180 outer_amt[j] -= outer_diff[j];
181 middle_amt[j] -= middle_diff[j];
185 printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
186 inner_color[i][1], inner_color[i][2], inner_color[i][3]);
187 printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
188 middle_color[i][0], middle_color[i][1], middle_color[i][2],
190 printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
191 outer_color[i][0], outer_color[i][1], outer_color[i][2],
196 for ( j = 0; j < 3; j++ ) {
201 for ( i = 6; i < 12; i++ ) {
203 for ( j = 0; j < 3; j++ ) {
204 diff = l->sky_color[j] - l->fog_color[j];
206 inner_color[i][j] = l->sky_color[j] - diff * 0.3;
207 middle_color[i][j] = l->sky_color[j] - diff * 0.9 + middle_amt[j];
208 outer_color[i][j] = l->fog_color[j] + outer_amt[j];
210 if ( middle_color[i][j] > 1.00 ) { middle_color[i][j] = 1.00; }
211 if ( middle_color[i][j] < 0.10 ) { middle_color[i][j] = 0.10; }
212 if ( outer_color[i][j] > 1.00 ) { outer_color[i][j] = 1.00; }
213 if ( outer_color[i][j] < 0.15 ) { outer_color[i][j] = 0.15; }
215 inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
218 for ( j = 0; j < 3; j++ ) {
219 outer_amt[j] += outer_diff[j];
220 middle_amt[j] += middle_diff[j];
224 printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
225 inner_color[i][1], inner_color[i][2], inner_color[i][3]);
226 printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
227 middle_color[i][0], middle_color[i][1], middle_color[i][2],
229 printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
230 outer_color[i][0], outer_color[i][1], outer_color[i][2],
237 /* Initialize the sky structure and colors */
238 void fgSkyInit( void ) {
239 printf("Initializing the sky\n");
243 /* regester fgSkyColorsInit() as an event to be run periodically */
244 fgEventRegister("fgSkyColorsInit()", fgSkyColorsInit,
245 FG_EVENT_READY, 30000);
250 void fgSkyRender( void ) {
254 float /* inner_color[4], middle_color[4], diff, */ east_dot, dot, angle;
257 f = current_aircraft.flight;
258 l = &cur_light_params;
261 /* printf("Rendering the sky.\n"); */
265 /* calculate the angle between v->surface_to_sun and
266 * v->surface_east. We do this so we can sort out the acos()
267 * ambiguity. I wish I could think of a more efficient way ... :-( */
268 east_dot = MAT3_DOT_PRODUCT(v->surface_to_sun, v->surface_east);
269 /* printf(" East dot product = %.2f\n", east_dot); */
271 /* calculate the angle between v->surface_to_sun and
272 * v->surface_south. this is how much we have to rotate the sky
273 * for it to align with the sun */
274 dot = MAT3_DOT_PRODUCT(v->surface_to_sun, v->surface_south);
275 /* printf(" Dot product = %.2f\n", dot); */
276 if ( east_dot >= 0 ) {
281 /*printf(" Sky needs to rotate = %.3f rads = %.1f degrees.\n",
282 angle, angle * RAD_TO_DEG); */
284 /* Translate to view position */
285 xglTranslatef( v->cur_zero_elev.x, v->cur_zero_elev.y, v->cur_zero_elev.z );
286 /* printf(" Translated to %.2f %.2f %.2f\n",
287 v->cur_zero_elev.x, v->cur_zero_elev.y, v->cur_zero_elev.z ); */
289 /* Rotate to proper orientation */
290 /* printf(" lon = %.2f lat = %.2f\n", FG_Longitude * RAD_TO_DEG,
291 FG_Latitude * RAD_TO_DEG); */
292 xglRotatef( FG_Longitude * RAD_TO_DEG, 0.0, 0.0, 1.0 );
293 xglRotatef( 90.0 - FG_Latitude * RAD_TO_DEG, 0.0, 1.0, 0.0 );
294 xglRotatef( angle * RAD_TO_DEG, 0.0, 0.0, 1.0 );
296 /* Draw inner/center section of sky*/
297 xglBegin( GL_TRIANGLE_FAN );
298 xglColor4fv(l->sky_color);
299 xglVertex3f(0.0, 0.0, CENTER_ELEV);
300 for ( i = 0; i < 12; i++ ) {
301 xglColor4fv( inner_color[i] );
302 xglVertex3fv( inner_vertex[i] );
304 xglColor4fv( inner_color[0] );
305 xglVertex3fv( inner_vertex[0] );
308 /* Draw the middle ring */
309 xglBegin( GL_TRIANGLE_STRIP );
310 for ( i = 0; i < 12; i++ ) {
311 xglColor4fv( middle_color[i] );
312 xglVertex3fv( middle_vertex[i] );
313 xglColor4fv( inner_color[i] );
314 xglVertex3fv( inner_vertex[i] );
316 xglColor4fv( middle_color[0] );
317 /* xglColor4f(1.0, 0.0, 0.0, 1.0); */
318 xglVertex3fv( middle_vertex[0] );
319 xglColor4fv( inner_color[0] );
320 /* xglColor4f(1.0, 0.0, 0.0, 1.0); */
321 xglVertex3fv( inner_vertex[0] );
324 /* Draw the outer ring */
325 xglBegin( GL_TRIANGLE_STRIP );
326 for ( i = 0; i < 12; i++ ) {
327 xglColor4fv( outer_color[i] );
328 xglVertex3fv( outer_vertex[i] );
329 xglColor4fv( middle_color[i] );
330 xglVertex3fv( middle_vertex[i] );
332 xglColor4fv( outer_color[0] );
333 xglVertex3fv( outer_vertex[0] );
334 xglColor4fv( middle_color[0] );
335 xglVertex3fv( middle_vertex[0] );
338 /* Draw the bottom skirt */
339 xglBegin( GL_TRIANGLE_STRIP );
340 for ( i = 0; i < 12; i++ ) {
341 xglColor4fv( l->fog_color );
342 xglVertex3fv( bottom_vertex[i] );
343 xglColor4fv( outer_color[i] );
344 xglVertex3fv( outer_vertex[i] );
346 xglColor4fv( l->fog_color );
347 xglVertex3fv( bottom_vertex[0] );
348 xglColor4fv( outer_color[0] );
349 xglVertex3fv( outer_vertex[0] );
357 /* Revision 1.8 1998/03/09 22:47:25 curt
358 /* Incorporated Durk's updates.
360 * Revision 1.7 1998/02/19 13:05:49 curt
361 * Incorporated some HUD tweaks from Michelle America.
362 * Tweaked the sky's sunset/rise colors.
363 * Other misc. tweaks.
365 * Revision 1.6 1998/02/07 15:29:32 curt
366 * Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss
367 * <chotchkiss@namg.us.anritsu.com>
369 * Revision 1.5 1998/01/27 00:47:48 curt
370 * Incorporated Paul Bleisch's <bleisch@chromatic.com> new debug message
371 * system and commandline/config file processing code.
373 * Revision 1.4 1998/01/26 15:54:28 curt
374 * Added a "skirt" to try to help hide gaps between scenery and sky. This will
375 * have to be revisited in the future.
377 * Revision 1.3 1998/01/19 19:26:59 curt
378 * Merged in make system changes from Bob Kuehne <rpk@sgi.com>
379 * This should simplify things tremendously.
381 * Revision 1.2 1998/01/19 18:40:17 curt
382 * Tons of little changes to clean up the code and to remove fatal errors
383 * when building with the c++ compiler.
385 * Revision 1.1 1998/01/07 03:16:19 curt
386 * Moved from .../Src/Scenery/ to .../Src/Astro/
388 * Revision 1.11 1997/12/30 22:22:38 curt
389 * Further integration of event manager.
391 * Revision 1.10 1997/12/30 20:47:53 curt
392 * Integrated new event manager with subsystem initializations.
394 * Revision 1.9 1997/12/30 13:06:57 curt
395 * A couple lighting tweaks ...
397 * Revision 1.8 1997/12/23 04:58:38 curt
398 * Tweaked the sky coloring a bit to build in structures to allow finer rgb
401 * Revision 1.7 1997/12/22 23:45:48 curt
402 * First stab at sunset/sunrise sky glow effects.
404 * Revision 1.6 1997/12/22 04:14:34 curt
405 * Aligned sky with sun so dusk/dawn effects can be correct relative to the sun.
407 * Revision 1.5 1997/12/19 23:34:59 curt
408 * Lot's of tweaking with sky rendering and lighting.
410 * Revision 1.4 1997/12/19 16:45:02 curt
411 * Working on scene rendering order and options.
413 * Revision 1.3 1997/12/18 23:32:36 curt
414 * First stab at sky dome actually starting to look reasonable. :-)
416 * Revision 1.2 1997/12/18 04:07:03 curt
417 * Worked on properly translating and positioning the sky dome.
419 * Revision 1.1 1997/12/17 23:14:30 curt
421 * Begin work on rendering the sky. (Rather than just using a clear screen.)