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/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
58 #define INNER_RADIUS 50000.0
59 #define INNER_ELEV 20000.0
60 #define MIDDLE_RADIUS 70000.0
61 #define MIDDLE_ELEV 8000.0
62 #define OUTER_RADIUS 80000.0
63 #define OUTER_ELEV 0.0
66 static float inner_vertex[12][3];
67 static float middle_vertex[12][3];
68 static float outer_vertex[12][3];
70 static float inner_color[12][4];
71 static float middle_color[12][4];
72 static float outer_color[12][4];
75 /* Calculate the sky structure vertices */
76 void fgSkyVerticesInit( void ) {
80 printf(" Generating the sky dome vertices.\n");
82 for ( i = 0; i < 12; i++ ) {
83 theta = (i * 30.0) * DEG_TO_RAD;
85 inner_vertex[i][0] = cos(theta) * INNER_RADIUS;
86 inner_vertex[i][1] = sin(theta) * INNER_RADIUS;
87 inner_vertex[i][2] = INNER_ELEV;
89 /* printf(" %.2f %.2f\n", cos(theta) * INNER_RADIUS,
90 sin(theta) * INNER_RADIUS); */
92 middle_vertex[i][0] = cos((double)theta) * MIDDLE_RADIUS;
93 middle_vertex[i][1] = sin((double)theta) * MIDDLE_RADIUS;
94 middle_vertex[i][2] = MIDDLE_ELEV;
96 outer_vertex[i][0] = cos((double)theta) * OUTER_RADIUS;
97 outer_vertex[i][1] = sin((double)theta) * OUTER_RADIUS;
98 outer_vertex[i][2] = OUTER_ELEV;
104 /* (Re)calculate the sky colors at each vertex */
105 void fgSkyColorsInit( void ) {
107 float sun_angle, diff;
108 float outer_param[3], outer_amt[3], outer_diff[3];
109 float middle_param[3], middle_amt[3], middle_diff[3];
112 l = &cur_light_params;
114 printf(" Generating the sky colors for each vertex.\n");
116 /* setup for the possibility of sunset effects */
117 sun_angle = l->sun_angle * RAD_TO_DEG;
118 printf(" Sun angle in degrees = %.2f\n", sun_angle);
120 if ( (sun_angle > 80.0) && (sun_angle < 100.0) ) {
122 outer_param[0] = (10.0 - fabs(90.0 - sun_angle)) / 25.0;
123 outer_param[1] = (10.0 - fabs(90.0 - sun_angle)) / 45.0;
124 outer_param[2] = 0.0;
126 middle_param[0] = (10.0 - fabs(90.0 - sun_angle)) / 40.0;
127 middle_param[1] = (10.0 - fabs(90.0 - sun_angle)) / 60.0;
128 middle_param[2] = 0.0;
130 outer_diff[0] = outer_param[0] / 6.0;
131 outer_diff[1] = outer_param[1] / 6.0;
132 outer_diff[2] = outer_param[2] / 6.0;
134 middle_diff[0] = middle_param[0] / 6.0;
135 middle_diff[1] = middle_param[1] / 6.0;
136 middle_diff[2] = middle_param[2] / 6.0;
138 outer_param[0] = outer_param[1] = outer_param[2] = 0.0;
139 middle_param[0] = middle_param[1] = middle_param[2] = 0.0;
141 outer_diff[0] = outer_diff[1] = outer_diff[2] = 0.0;
142 middle_diff[0] = middle_diff[1] = middle_diff[2] = 0.0;
144 /* printf(" outer_red_param = %.2f outer_red_diff = %.2f\n",
145 outer_red_param, outer_red_diff); */
147 /* calculate transition colors between sky and fog */
148 for ( j = 0; j < 3; j++ ) {
149 outer_amt[j] = outer_param[j];
150 middle_amt[j] = middle_param[j];
153 for ( i = 0; i < 6; i++ ) {
154 for ( j = 0; j < 3; j++ ) {
155 diff = l->sky_color[j] - l->fog_color[j];
157 inner_color[i][j] = l->sky_color[j] - diff * 0.3;
158 middle_color[i][j] = l->sky_color[j] - diff * 0.9 + middle_amt[j];
159 outer_color[i][j] = l->fog_color[j] + outer_amt[j];
161 if ( middle_color[i][j] > 1.00 ) { middle_color[i][j] = 1.00; }
162 if ( middle_color[i][j] < 0.10 ) { middle_color[i][j] = 0.10; }
163 if ( outer_color[i][j] > 1.00 ) { outer_color[i][j] = 1.00; }
164 if ( outer_color[i][j] < 0.10 ) { outer_color[i][j] = 0.10; }
166 inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
169 for ( j = 0; j < 3; j++ ) {
170 outer_amt[j] -= outer_diff[j];
171 middle_amt[j] -= middle_diff[j];
175 printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
176 inner_color[i][1], inner_color[i][2], inner_color[i][3]);
177 printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
178 middle_color[i][0], middle_color[i][1], middle_color[i][2],
180 printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
181 outer_color[i][0], outer_color[i][1], outer_color[i][2],
186 for ( j = 0; j < 3; j++ ) {
191 for ( i = 6; i < 12; i++ ) {
193 for ( j = 0; j < 3; j++ ) {
194 diff = l->sky_color[j] - l->fog_color[j];
196 inner_color[i][j] = l->sky_color[j] - diff * 0.3;
197 middle_color[i][j] = l->sky_color[j] - diff * 0.9 + middle_amt[j];
198 outer_color[i][j] = l->fog_color[j] + outer_amt[j];
200 if ( middle_color[i][j] > 1.00 ) { middle_color[i][j] = 1.00; }
201 if ( middle_color[i][j] < 0.10 ) { middle_color[i][j] = 0.10; }
202 if ( outer_color[i][j] > 1.00 ) { outer_color[i][j] = 1.00; }
203 if ( outer_color[i][j] < 0.15 ) { outer_color[i][j] = 0.15; }
205 inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
208 for ( j = 0; j < 3; j++ ) {
209 outer_amt[j] += outer_diff[j];
210 middle_amt[j] += middle_diff[j];
214 printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
215 inner_color[i][1], inner_color[i][2], inner_color[i][3]);
216 printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
217 middle_color[i][0], middle_color[i][1], middle_color[i][2],
219 printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
220 outer_color[i][0], outer_color[i][1], outer_color[i][2],
227 /* Initialize the sky structure and colors */
228 void fgSkyInit( void ) {
229 printf("Initializing the sky\n");
233 /* regester fgSkyColorsInit() as an event to be run periodically */
234 fgEventRegister("fgSkyColorsInit()", fgSkyColorsInit,
235 FG_EVENT_READY, 30000);
240 void fgSkyRender( void ) {
244 float /* inner_color[4], middle_color[4], diff, */ east_dot, dot, angle;
247 f = ¤t_aircraft.flight;
248 l = &cur_light_params;
251 /* printf("Rendering the sky.\n"); */
255 /* calculate the angle between v->surface_to_sun and
256 * v->surface_east. We do this so we can sort out the acos()
257 * ambiguity. I wish I could think of a more efficient way ... :-( */
258 east_dot = MAT3_DOT_PRODUCT(v->surface_to_sun, v->surface_east);
259 /* printf(" East dot product = %.2f\n", east_dot); */
261 /* calculate the angle between v->surface_to_sun and
262 * v->surface_south. this is how much we have to rotate the sky
263 * for it to align with the sun */
264 dot = MAT3_DOT_PRODUCT(v->surface_to_sun, v->surface_south);
265 /* printf(" Dot product = %.2f\n", dot); */
266 if ( east_dot >= 0 ) {
271 /*printf(" Sky needs to rotate = %.3f rads = %.1f degrees.\n",
272 angle, angle * RAD_TO_DEG); */
274 /* Translate to view position */
275 xglTranslatef( v->cur_zero_elev.x, v->cur_zero_elev.y, v->cur_zero_elev.z );
276 /* printf(" Translated to %.2f %.2f %.2f\n",
277 v->cur_zero_elev.x, v->cur_zero_elev.y, v->cur_zero_elev.z ); */
279 /* Rotate to proper orientation */
280 /* printf(" lon = %.2f lat = %.2f\n", FG_Longitude * RAD_TO_DEG,
281 FG_Latitude * RAD_TO_DEG); */
282 xglRotatef( FG_Longitude * RAD_TO_DEG, 0.0, 0.0, 1.0 );
283 xglRotatef( 90.0 - FG_Latitude * RAD_TO_DEG, 0.0, 1.0, 0.0 );
284 xglRotatef( angle * RAD_TO_DEG, 0.0, 0.0, 1.0 );
286 /* Draw inner/center section of sky*/
287 xglBegin( GL_TRIANGLE_FAN );
288 xglColor4fv(l->sky_color);
289 xglVertex3f(0.0, 0.0, CENTER_ELEV);
290 for ( i = 0; i < 12; i++ ) {
291 xglColor4fv( inner_color[i] );
292 xglVertex3fv( inner_vertex[i] );
294 xglColor4fv( inner_color[0] );
295 xglVertex3fv( inner_vertex[0] );
298 /* Draw the middle ring */
299 xglBegin( GL_TRIANGLE_STRIP );
300 for ( i = 0; i < 12; i++ ) {
301 xglColor4fv( middle_color[i] );
302 xglVertex3fv( middle_vertex[i] );
303 xglColor4fv( inner_color[i] );
304 xglVertex3fv( inner_vertex[i] );
306 xglColor4fv( middle_color[0] );
307 /* xglColor4f(1.0, 0.0, 0.0, 1.0); */
308 xglVertex3fv( middle_vertex[0] );
309 xglColor4fv( inner_color[0] );
310 /* xglColor4f(1.0, 0.0, 0.0, 1.0); */
311 xglVertex3fv( inner_vertex[0] );
314 /* Draw the outer ring */
315 xglBegin( GL_TRIANGLE_STRIP );
316 for ( i = 0; i < 12; i++ ) {
317 xglColor4fv( outer_color[i] );
318 xglVertex3fv( outer_vertex[i] );
319 xglColor4fv( middle_color[i] );
320 xglVertex3fv( middle_vertex[i] );
322 xglColor4fv( outer_color[0] );
323 xglVertex3fv( outer_vertex[0] );
324 xglColor4fv( middle_color[0] );
325 xglVertex3fv( middle_vertex[0] );
333 /* Revision 1.3 1998/01/19 19:26:59 curt
334 /* Merged in make system changes from Bob Kuehne <rpk@sgi.com>
335 /* This should simplify things tremendously.
337 * Revision 1.2 1998/01/19 18:40:17 curt
338 * Tons of little changes to clean up the code and to remove fatal errors
339 * when building with the c++ compiler.
341 * Revision 1.1 1998/01/07 03:16:19 curt
342 * Moved from .../Src/Scenery/ to .../Src/Astro/
344 * Revision 1.11 1997/12/30 22:22:38 curt
345 * Further integration of event manager.
347 * Revision 1.10 1997/12/30 20:47:53 curt
348 * Integrated new event manager with subsystem initializations.
350 * Revision 1.9 1997/12/30 13:06:57 curt
351 * A couple lighting tweaks ...
353 * Revision 1.8 1997/12/23 04:58:38 curt
354 * Tweaked the sky coloring a bit to build in structures to allow finer rgb
357 * Revision 1.7 1997/12/22 23:45:48 curt
358 * First stab at sunset/sunrise sky glow effects.
360 * Revision 1.6 1997/12/22 04:14:34 curt
361 * Aligned sky with sun so dusk/dawn effects can be correct relative to the sun.
363 * Revision 1.5 1997/12/19 23:34:59 curt
364 * Lot's of tweaking with sky rendering and lighting.
366 * Revision 1.4 1997/12/19 16:45:02 curt
367 * Working on scene rendering order and options.
369 * Revision 1.3 1997/12/18 23:32:36 curt
370 * First stab at sky dome actually starting to look reasonable. :-)
372 * Revision 1.2 1997/12/18 04:07:03 curt
373 * Worked on properly translating and positioning the sky dome.
375 * Revision 1.1 1997/12/17 23:14:30 curt
377 * Begin work on rendering the sky. (Rather than just using a clear screen.)