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 **************************************************************************/
39 #include "../XGL/xgl.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"
52 #include "../Include/general.h"
55 /* in meters of course */
56 #define CENTER_ELEV 25000.0
57 #define INNER_RADIUS 50000.0
58 #define INNER_ELEV 20000.0
59 #define MIDDLE_RADIUS 70000.0
60 #define MIDDLE_ELEV 8000.0
61 #define OUTER_RADIUS 80000.0
62 #define OUTER_ELEV 0.0
65 static float inner_vertex[12][3];
66 static float middle_vertex[12][3];
67 static float outer_vertex[12][3];
69 static float inner_color[12][4];
70 static float middle_color[12][4];
71 static float outer_color[12][4];
74 /* Calculate the sky structure vertices */
75 void fgSkyVerticesInit() {
79 printf(" Generating the sky dome vertices.\n");
81 for ( i = 0; i < 12; i++ ) {
82 theta = (i * 30.0) * DEG_TO_RAD;
84 inner_vertex[i][0] = cos(theta) * INNER_RADIUS;
85 inner_vertex[i][1] = sin(theta) * INNER_RADIUS;
86 inner_vertex[i][2] = INNER_ELEV;
88 /* printf(" %.2f %.2f\n", cos(theta) * INNER_RADIUS,
89 sin(theta) * INNER_RADIUS); */
91 middle_vertex[i][0] = cos((double)theta) * MIDDLE_RADIUS;
92 middle_vertex[i][1] = sin((double)theta) * MIDDLE_RADIUS;
93 middle_vertex[i][2] = MIDDLE_ELEV;
95 outer_vertex[i][0] = cos((double)theta) * OUTER_RADIUS;
96 outer_vertex[i][1] = sin((double)theta) * OUTER_RADIUS;
97 outer_vertex[i][2] = OUTER_ELEV;
103 /* (Re)calculate the sky colors at each vertex */
104 void fgSkyColorsInit() {
106 float sun_angle, diff;
107 float outer_param[3], outer_amt[3], outer_diff[3];
108 float middle_param[3], middle_amt[3], middle_diff[3];
111 l = &cur_light_params;
113 printf(" Generating the sky colors for each vertex.\n");
115 /* setup for the possibility of sunset effects */
116 sun_angle = l->sun_angle * RAD_TO_DEG;
117 printf(" Sun angle in degrees = %.2f\n", sun_angle);
119 if ( (sun_angle > 80.0) && (sun_angle < 100.0) ) {
121 outer_param[0] = (10.0 - fabs(90.0 - sun_angle)) / 25.0;
122 outer_param[1] = (10.0 - fabs(90.0 - sun_angle)) / 45.0;
123 outer_param[2] = 0.0;
125 middle_param[0] = (10.0 - fabs(90.0 - sun_angle)) / 40.0;
126 middle_param[1] = (10.0 - fabs(90.0 - sun_angle)) / 60.0;
127 middle_param[2] = 0.0;
129 outer_diff[0] = outer_param[0] / 6.0;
130 outer_diff[1] = outer_param[1] / 6.0;
131 outer_diff[2] = outer_param[2] / 6.0;
133 middle_diff[0] = middle_param[0] / 6.0;
134 middle_diff[1] = middle_param[1] / 6.0;
135 middle_diff[2] = middle_param[2] / 6.0;
137 outer_param[0] = outer_param[1] = outer_param[2] = 0.0;
138 middle_param[0] = middle_param[1] = middle_param[2] = 0.0;
140 outer_diff[0] = outer_diff[1] = outer_diff[2] = 0.0;
141 middle_diff[0] = middle_diff[1] = middle_diff[2] = 0.0;
143 /* printf(" outer_red_param = %.2f outer_red_diff = %.2f\n",
144 outer_red_param, outer_red_diff); */
146 /* calculate transition colors between sky and fog */
147 for ( j = 0; j < 3; j++ ) {
148 outer_amt[j] = outer_param[j];
149 middle_amt[j] = middle_param[j];
152 for ( i = 0; i < 6; i++ ) {
153 for ( j = 0; j < 3; j++ ) {
154 diff = l->sky_color[j] - l->fog_color[j];
156 inner_color[i][j] = l->sky_color[j] - diff * 0.3;
157 middle_color[i][j] = l->sky_color[j] - diff * 0.9 + middle_amt[j];
158 outer_color[i][j] = l->fog_color[j] + outer_amt[j];
160 if ( middle_color[i][j] > 1.00 ) { middle_color[i][j] = 1.00; }
161 if ( middle_color[i][j] < 0.10 ) { middle_color[i][j] = 0.10; }
162 if ( outer_color[i][j] > 1.00 ) { outer_color[i][j] = 1.00; }
163 if ( outer_color[i][j] < 0.10 ) { outer_color[i][j] = 0.10; }
165 inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
168 for ( j = 0; j < 3; j++ ) {
169 outer_amt[j] -= outer_diff[j];
170 middle_amt[j] -= middle_diff[j];
174 printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
175 inner_color[i][1], inner_color[i][2], inner_color[i][3]);
176 printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
177 middle_color[i][0], middle_color[i][1], middle_color[i][2],
179 printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
180 outer_color[i][0], outer_color[i][1], outer_color[i][2],
185 for ( j = 0; j < 3; j++ ) {
190 for ( i = 6; i < 12; i++ ) {
192 for ( j = 0; j < 3; j++ ) {
193 diff = l->sky_color[j] - l->fog_color[j];
195 inner_color[i][j] = l->sky_color[j] - diff * 0.3;
196 middle_color[i][j] = l->sky_color[j] - diff * 0.9 + middle_amt[j];
197 outer_color[i][j] = l->fog_color[j] + outer_amt[j];
199 if ( middle_color[i][j] > 1.00 ) { middle_color[i][j] = 1.00; }
200 if ( middle_color[i][j] < 0.10 ) { middle_color[i][j] = 0.10; }
201 if ( outer_color[i][j] > 1.00 ) { outer_color[i][j] = 1.00; }
202 if ( outer_color[i][j] < 0.15 ) { outer_color[i][j] = 0.15; }
204 inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
207 for ( j = 0; j < 3; j++ ) {
208 outer_amt[j] += outer_diff[j];
209 middle_amt[j] += middle_diff[j];
213 printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
214 inner_color[i][1], inner_color[i][2], inner_color[i][3]);
215 printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
216 middle_color[i][0], middle_color[i][1], middle_color[i][2],
218 printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
219 outer_color[i][0], outer_color[i][1], outer_color[i][2],
226 /* Initialize the sky structure and colors */
228 printf("Initializing the sky\n");
232 /* regester fgSkyColorsInit() as an event to be run periodically */
233 fgEventRegister("fgSkyColorsInit()", fgSkyColorsInit,
234 FG_EVENT_READY, 30000);
243 float /* inner_color[4], middle_color[4], diff, */ east_dot, dot, angle;
246 f = ¤t_aircraft.flight;
247 l = &cur_light_params;
250 /* printf("Rendering the sky.\n"); */
254 /* calculate the angle between v->surface_to_sun and
255 * v->surface_east. We do this so we can sort out the acos()
256 * ambiguity. I wish I could think of a more efficient way ... :-( */
257 east_dot = MAT3_DOT_PRODUCT(v->surface_to_sun, v->surface_east);
258 /* printf(" East dot product = %.2f\n", east_dot); */
260 /* calculate the angle between v->surface_to_sun and
261 * v->surface_south. this is how much we have to rotate the sky
262 * for it to align with the sun */
263 dot = MAT3_DOT_PRODUCT(v->surface_to_sun, v->surface_south);
264 /* printf(" Dot product = %.2f\n", dot); */
265 if ( east_dot >= 0 ) {
270 /*printf(" Sky needs to rotate = %.3f rads = %.1f degrees.\n",
271 angle, angle * RAD_TO_DEG); */
273 /* Translate to view position */
274 xglTranslatef( v->cur_zero_elev.x, v->cur_zero_elev.y, v->cur_zero_elev.z );
275 /* printf(" Translated to %.2f %.2f %.2f\n",
276 v->cur_zero_elev.x, v->cur_zero_elev.y, v->cur_zero_elev.z ); */
278 /* Rotate to proper orientation */
279 /* printf(" lon = %.2f lat = %.2f\n", FG_Longitude * RAD_TO_DEG,
280 FG_Latitude * RAD_TO_DEG); */
281 xglRotatef( FG_Longitude * RAD_TO_DEG, 0.0, 0.0, 1.0 );
282 xglRotatef( 90.0 - FG_Latitude * RAD_TO_DEG, 0.0, 1.0, 0.0 );
283 xglRotatef( angle * RAD_TO_DEG, 0.0, 0.0, 1.0 );
285 /* Draw inner/center section of sky*/
286 xglBegin( GL_TRIANGLE_FAN );
287 xglColor4fv(l->sky_color);
288 xglVertex3f(0.0, 0.0, CENTER_ELEV);
289 for ( i = 0; i < 12; i++ ) {
290 xglColor4fv( inner_color[i] );
291 xglVertex3fv( inner_vertex[i] );
293 xglColor4fv( inner_color[0] );
294 xglVertex3fv( inner_vertex[0] );
297 /* Draw the middle ring */
298 xglBegin( GL_TRIANGLE_STRIP );
299 for ( i = 0; i < 12; i++ ) {
300 xglColor4fv( middle_color[i] );
301 xglVertex3fv( middle_vertex[i] );
302 xglColor4fv( inner_color[i] );
303 xglVertex3fv( inner_vertex[i] );
305 xglColor4fv( middle_color[0] );
306 /* xglColor4f(1.0, 0.0, 0.0, 1.0); */
307 xglVertex3fv( middle_vertex[0] );
308 xglColor4fv( inner_color[0] );
309 /* xglColor4f(1.0, 0.0, 0.0, 1.0); */
310 xglVertex3fv( inner_vertex[0] );
313 /* Draw the outer ring */
314 xglBegin( GL_TRIANGLE_STRIP );
315 for ( i = 0; i < 12; i++ ) {
316 xglColor4fv( outer_color[i] );
317 xglVertex3fv( outer_vertex[i] );
318 xglColor4fv( middle_color[i] );
319 xglVertex3fv( middle_vertex[i] );
321 xglColor4fv( outer_color[0] );
322 xglVertex3fv( outer_vertex[0] );
323 xglColor4fv( middle_color[0] );
324 xglVertex3fv( middle_vertex[0] );
332 /* Revision 1.1 1998/01/07 03:16:19 curt
333 /* Moved from .../Src/Scenery/ to .../Src/Astro/
335 * Revision 1.11 1997/12/30 22:22:38 curt
336 * Further integration of event manager.
338 * Revision 1.10 1997/12/30 20:47:53 curt
339 * Integrated new event manager with subsystem initializations.
341 * Revision 1.9 1997/12/30 13:06:57 curt
342 * A couple lighting tweaks ...
344 * Revision 1.8 1997/12/23 04:58:38 curt
345 * Tweaked the sky coloring a bit to build in structures to allow finer rgb
348 * Revision 1.7 1997/12/22 23:45:48 curt
349 * First stab at sunset/sunrise sky glow effects.
351 * Revision 1.6 1997/12/22 04:14:34 curt
352 * Aligned sky with sun so dusk/dawn effects can be correct relative to the sun.
354 * Revision 1.5 1997/12/19 23:34:59 curt
355 * Lot's of tweaking with sky rendering and lighting.
357 * Revision 1.4 1997/12/19 16:45:02 curt
358 * Working on scene rendering order and options.
360 * Revision 1.3 1997/12/18 23:32:36 curt
361 * First stab at sky dome actually starting to look reasonable. :-)
363 * Revision 1.2 1997/12/18 04:07:03 curt
364 * Worked on properly translating and positioning the sky dome.
366 * Revision 1.1 1997/12/17 23:14:30 curt
368 * Begin work on rendering the sky. (Rather than just using a clear screen.)