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root/radiance/ray/src/gen/gensky.c
Revision: 2.22
Committed: Sun Nov 16 10:29:38 2003 UTC (20 years, 4 months ago) by schorsch
Content type: text/plain
Branch: MAIN
Changes since 2.21: +51 -33 lines
Log Message:
Continued ANSIfication and reduced other compile warnings.

File Contents

# User Rev Content
1 greg 1.1 #ifndef lint
2 schorsch 2.22 static const char RCSid[] = "$Id: gensky.c,v 2.21 2003/07/27 22:12:02 schorsch Exp $";
3 greg 1.1 #endif
4     /*
5     * gensky.c - program to generate sky functions.
6     * Our zenith is along the Z-axis, the X-axis
7     * points east, and the Y-axis points north.
8     * Radiance is in watts/steradian/sq. meter.
9     *
10     * 3/26/86
11     */
12    
13     #include <stdio.h>
14 greg 2.20 #include <stdlib.h>
15     #include <string.h>
16 greg 1.1 #include <math.h>
17 greg 2.17 #include <ctype.h>
18    
19 greg 1.6 #include "color.h"
20 greg 1.1
21 schorsch 2.22 extern int jdate(int month, int day);
22     extern double stadj(int jd);
23     extern double sdec(int jd);
24     extern double salt(double sd, double st);
25     extern double sazi(double sd, double st);
26 greg 1.1
27 greg 2.17 #ifndef PI
28     #define PI 3.14159265358979323846
29     #endif
30 greg 1.1
31     #define DOT(v1,v2) (v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2])
32    
33 greg 2.13 #define S_CLEAR 1
34     #define S_OVER 2
35     #define S_UNIF 3
36     #define S_INTER 4
37    
38 schorsch 2.21 #define overcast ((skytype==S_OVER)|(skytype==S_UNIF))
39 greg 2.13
40 greg 1.1 double normsc();
41     /* sun calculation constants */
42     extern double s_latitude;
43     extern double s_longitude;
44     extern double s_meridian;
45 greg 2.17
46     #undef toupper
47     #define toupper(c) ((c) & ~0x20) /* ASCII trick to convert case */
48    
49     /* European and North American zones */
50     struct {
51     char zname[8]; /* time zone name (all caps) */
52     float zmer; /* standard meridian */
53     } tzone[] = {
54 schorsch 2.22 {"YST", 135}, {"YDT", 120},
55     {"PST", 120}, {"PDT", 105},
56     {"MST", 105}, {"MDT", 90},
57     {"CST", 90}, {"CDT", 75},
58     {"EST", 75}, {"EDT", 60},
59     {"AST", 60}, {"ADT", 45},
60     {"NST", 52.5}, {"NDT", 37.5},
61     {"GMT", 0}, {"BST", -15},
62     {"CET", -15}, {"CEST", -30},
63     {"EET", -30}, {"EEST", -45},
64     {"AST", -45}, {"ADT", -60},
65     {"GST", -60}, {"GDT", -75},
66     {"IST", -82.5}, {"IDT", -97.5},
67     {"JST", -135}, {"NDT", -150},
68     {"NZST", -180}, {"NZDT", -195},
69     {"", 0}
70 greg 2.17 };
71 greg 1.1 /* required values */
72 greg 2.3 int month, day; /* date */
73 greg 2.5 double hour; /* time */
74     int tsolar; /* 0=standard, 1=solar */
75 greg 2.3 double altitude, azimuth; /* or solar angles */
76 greg 1.1 /* default values */
77 greg 2.13 int skytype = S_CLEAR; /* sky type */
78 greg 1.1 int dosun = 1;
79 greg 2.12 double zenithbr = 0.0;
80     int u_zenith = 0; /* -1=irradiance, 1=radiance */
81 greg 1.1 double turbidity = 2.75;
82     double gprefl = 0.2;
83     /* computed values */
84     double sundir[3];
85     double groundbr;
86     double F2;
87 greg 2.12 double solarbr = 0.0;
88     int u_solar = 0; /* -1=irradiance, 1=radiance */
89 greg 1.1
90     char *progname;
91     char errmsg[128];
92    
93 schorsch 2.22 void computesky(void);
94     void printsky(void);
95     void printdefaults(void);
96     void userror(char *msg);
97     double normsc(void);
98     void cvthour(char *hs);
99     void printhead(register int ac, register char **av);
100    
101 greg 1.1
102 schorsch 2.22 int
103 greg 1.1 main(argc, argv)
104     int argc;
105     char *argv[];
106     {
107     int i;
108    
109     progname = argv[0];
110     if (argc == 2 && !strcmp(argv[1], "-defaults")) {
111     printdefaults();
112     exit(0);
113     }
114     if (argc < 4)
115     userror("arg count");
116 greg 2.3 if (!strcmp(argv[1], "-ang")) {
117     altitude = atof(argv[2]) * (PI/180);
118     azimuth = atof(argv[3]) * (PI/180);
119     month = 0;
120     } else {
121     month = atoi(argv[1]);
122 greg 2.6 if (month < 1 || month > 12)
123     userror("bad month");
124 greg 2.3 day = atoi(argv[2]);
125 greg 2.6 if (day < 1 || day > 31)
126     userror("bad day");
127 greg 2.16 cvthour(argv[3]);
128 greg 2.3 }
129 greg 1.1 for (i = 4; i < argc; i++)
130     if (argv[i][0] == '-' || argv[i][0] == '+')
131     switch (argv[i][1]) {
132     case 's':
133 greg 2.13 skytype = S_CLEAR;
134 greg 1.1 dosun = argv[i][0] == '+';
135     break;
136 greg 2.8 case 'r':
137 greg 2.12 case 'R':
138     u_solar = argv[i][1]=='R' ? -1 : 1;
139 greg 2.8 solarbr = atof(argv[++i]);
140     break;
141 greg 1.1 case 'c':
142 greg 2.13 skytype = S_OVER;
143 greg 1.1 break;
144 greg 2.13 case 'u':
145     skytype = S_UNIF;
146     break;
147     case 'i':
148     skytype = S_INTER;
149     dosun = argv[i][0] == '+';
150     break;
151 greg 1.1 case 't':
152     turbidity = atof(argv[++i]);
153     break;
154     case 'b':
155 greg 2.12 case 'B':
156     u_zenith = argv[i][1]=='B' ? -1 : 1;
157 greg 1.1 zenithbr = atof(argv[++i]);
158     break;
159     case 'g':
160     gprefl = atof(argv[++i]);
161     break;
162     case 'a':
163     s_latitude = atof(argv[++i]) * (PI/180);
164     break;
165     case 'o':
166     s_longitude = atof(argv[++i]) * (PI/180);
167     break;
168     case 'm':
169     s_meridian = atof(argv[++i]) * (PI/180);
170     break;
171     default:
172     sprintf(errmsg, "unknown option: %s", argv[i]);
173     userror(errmsg);
174     }
175     else
176     userror("bad option");
177 greg 1.5
178 greg 2.18 if (fabs(s_meridian-s_longitude) > 45*PI/180)
179 greg 1.5 fprintf(stderr,
180     "%s: warning: %.1f hours btwn. standard meridian and longitude\n",
181     progname, (s_longitude-s_meridian)*12/PI);
182 greg 1.1
183     printhead(argc, argv);
184    
185     computesky();
186     printsky();
187 greg 2.15
188     exit(0);
189 greg 1.1 }
190    
191    
192 schorsch 2.22 void
193     computesky(void) /* compute sky parameters */
194 greg 1.1 {
195 greg 2.12 double normfactor;
196 greg 1.1 /* compute solar direction */
197 greg 2.3 if (month) { /* from date and time */
198     int jd;
199     double sd, st;
200    
201     jd = jdate(month, day); /* Julian date */
202     sd = sdec(jd); /* solar declination */
203 greg 2.5 if (tsolar) /* solar time */
204     st = hour;
205     else
206     st = hour + stadj(jd);
207 greg 2.3 altitude = salt(sd, st);
208     azimuth = sazi(sd, st);
209 greg 2.17 printf("# Local solar time: %.2f\n", st);
210 greg 2.13 printf("# Solar altitude and azimuth: %.1f %.1f\n",
211 greg 2.11 180./PI*altitude, 180./PI*azimuth);
212 greg 2.9 }
213 greg 2.13 if (!overcast && altitude > 87.*PI/180.) {
214 greg 2.9 fprintf(stderr,
215     "%s: warning - sun too close to zenith, reducing altitude to 87 degrees\n",
216     progname);
217     printf(
218     "# warning - sun too close to zenith, reducing altitude to 87 degrees\n");
219     altitude = 87.*PI/180.;
220 greg 2.3 }
221 greg 1.1 sundir[0] = -sin(azimuth)*cos(altitude);
222     sundir[1] = -cos(azimuth)*cos(altitude);
223     sundir[2] = sin(altitude);
224    
225 greg 2.12 /* Compute normalization factor */
226 greg 2.13 switch (skytype) {
227     case S_UNIF:
228 greg 2.12 normfactor = 1.0;
229 greg 2.13 break;
230     case S_OVER:
231 greg 2.12 normfactor = 0.777778;
232 greg 2.13 break;
233     case S_CLEAR:
234 greg 2.12 F2 = 0.274*(0.91 + 10.0*exp(-3.0*(PI/2.0-altitude)) +
235     0.45*sundir[2]*sundir[2]);
236 greg 2.13 normfactor = normsc()/F2/PI;
237     break;
238     case S_INTER:
239     F2 = (2.739 + .9891*sin(.3119+2.6*altitude)) *
240     exp(-(PI/2.0-altitude)*(.4441+1.48*altitude));
241     normfactor = normsc()/F2/PI;
242     break;
243 greg 2.12 }
244 greg 1.1 /* Compute zenith brightness */
245 greg 2.12 if (u_zenith == -1)
246     zenithbr /= normfactor*PI;
247     else if (u_zenith == 0) {
248 greg 2.13 if (overcast)
249 greg 1.1 zenithbr = 8.6*sundir[2] + .123;
250 greg 2.12 else
251 greg 1.1 zenithbr = (1.376*turbidity-1.81)*tan(altitude)+0.38;
252 greg 2.13 if (skytype == S_INTER)
253     zenithbr = (zenithbr + 8.6*sundir[2] + .123)/2.0;
254 greg 2.12 if (zenithbr < 0.0)
255     zenithbr = 0.0;
256     else
257 greg 1.6 zenithbr *= 1000.0/SKYEFFICACY;
258 greg 2.12 }
259 greg 1.1 /* Compute horizontal radiance */
260 greg 2.12 groundbr = zenithbr*normfactor;
261 greg 2.13 printf("# Ground ambient level: %.1f\n", groundbr);
262 greg 2.14 if (!overcast && sundir[2] > 0.0 && (!u_solar || solarbr > 0.0)) {
263 greg 2.12 if (u_solar == -1)
264     solarbr /= 6e-5*sundir[2];
265 greg 2.13 else if (u_solar == 0) {
266 greg 2.12 solarbr = 1.5e9/SUNEFFICACY *
267     (1.147 - .147/(sundir[2]>.16?sundir[2]:.16));
268 greg 2.13 if (skytype == S_INTER)
269     solarbr *= 0.15; /* fudge factor! */
270     }
271 greg 2.12 groundbr += 6e-5/PI*solarbr*sundir[2];
272     } else
273     dosun = 0;
274 greg 1.1 groundbr *= gprefl;
275     }
276    
277    
278 schorsch 2.22 void
279     printsky(void) /* print out sky */
280 greg 1.1 {
281     if (dosun) {
282     printf("\nvoid light solar\n");
283     printf("0\n0\n");
284 greg 1.6 printf("3 %.2e %.2e %.2e\n", solarbr, solarbr, solarbr);
285 greg 1.1 printf("\nsolar source sun\n");
286     printf("0\n0\n");
287     printf("4 %f %f %f 0.5\n", sundir[0], sundir[1], sundir[2]);
288     }
289    
290     printf("\nvoid brightfunc skyfunc\n");
291 greg 2.13 printf("2 skybr skybright.cal\n");
292 greg 1.1 printf("0\n");
293 greg 2.13 if (overcast)
294     printf("3 %d %.2e %.2e\n", skytype, zenithbr, groundbr);
295 greg 1.1 else
296 greg 2.13 printf("7 %d %.2e %.2e %.2e %f %f %f\n",
297     skytype, zenithbr, groundbr, F2,
298     sundir[0], sundir[1], sundir[2]);
299 greg 1.1 }
300    
301    
302 schorsch 2.22 void
303     printdefaults(void) /* print default values */
304 greg 1.1 {
305 greg 2.13 switch (skytype) {
306     case S_OVER:
307 greg 1.1 printf("-c\t\t\t\t# Cloudy sky\n");
308 greg 2.13 break;
309     case S_UNIF:
310     printf("-u\t\t\t\t# Uniform cloudy sky\n");
311     break;
312     case S_INTER:
313     if (dosun)
314     printf("+i\t\t\t\t# Intermediate sky with sun\n");
315     else
316     printf("-i\t\t\t\t# Intermediate sky without sun\n");
317     break;
318     case S_CLEAR:
319     if (dosun)
320     printf("+s\t\t\t\t# Sunny sky with sun\n");
321     else
322     printf("-s\t\t\t\t# Sunny sky without sun\n");
323     break;
324     }
325 greg 1.1 printf("-g %f\t\t\t# Ground plane reflectance\n", gprefl);
326     if (zenithbr > 0.0)
327     printf("-b %f\t\t\t# Zenith radiance (watts/ster/m2\n", zenithbr);
328     else
329     printf("-t %f\t\t\t# Atmospheric turbidity\n", turbidity);
330     printf("-a %f\t\t\t# Site latitude (degrees)\n", s_latitude*(180/PI));
331     printf("-o %f\t\t\t# Site longitude (degrees)\n", s_longitude*(180/PI));
332     printf("-m %f\t\t\t# Standard meridian (degrees)\n", s_meridian*(180/PI));
333     }
334    
335    
336 schorsch 2.22 void
337     userror( /* print usage error and quit */
338     char *msg
339     )
340 greg 1.1 {
341     if (msg != NULL)
342     fprintf(stderr, "%s: Use error - %s\n", progname, msg);
343     fprintf(stderr, "Usage: %s month day hour [options]\n", progname);
344 greg 2.3 fprintf(stderr, " Or: %s -ang altitude azimuth [options]\n", progname);
345 greg 1.1 fprintf(stderr, " Or: %s -defaults\n", progname);
346     exit(1);
347     }
348    
349    
350     double
351 schorsch 2.22 normsc(void) /* compute normalization factor (E0*F2/L0) */
352 greg 1.1 {
353 greg 2.13 static double nfc[2][5] = {
354     /* clear sky approx. */
355     {2.766521, 0.547665, -0.369832, 0.009237, 0.059229},
356     /* intermediate sky approx. */
357     {3.5556, -2.7152, -1.3081, 1.0660, 0.60227},
358     };
359     register double *nf;
360 greg 1.1 double x, nsc;
361     register int i;
362     /* polynomial approximation */
363 greg 2.13 nf = nfc[skytype==S_INTER];
364     x = (altitude - PI/4.0)/(PI/4.0);
365     nsc = nf[i=4];
366     while (i--)
367 greg 1.1 nsc = nsc*x + nf[i];
368    
369     return(nsc);
370 greg 2.16 }
371    
372    
373 schorsch 2.22 void
374     cvthour( /* convert hour string */
375     char *hs
376     )
377 greg 2.16 {
378     register char *cp = hs;
379 greg 2.17 register int i, j;
380 greg 2.16
381 schorsch 2.21 if ( (tsolar = *cp == '+') ) cp++; /* solar time? */
382 greg 2.17 while (isdigit(*cp)) cp++;
383     if (*cp == ':')
384     hour = atoi(hs) + atoi(++cp)/60.0;
385     else {
386 greg 2.16 hour = atof(hs);
387 greg 2.17 if (*cp == '.') cp++;
388     }
389     while (isdigit(*cp)) cp++;
390     if (!*cp)
391     return;
392     if (tsolar || !isalpha(*cp)) {
393     fprintf(stderr, "%s: bad time format: %s\n", progname, hs);
394     exit(1);
395     }
396     i = 0;
397     do {
398     for (j = 0; cp[j]; j++)
399     if (toupper(cp[j]) != tzone[i].zname[j])
400     break;
401     if (!cp[j] && !tzone[i].zname[j]) {
402     s_meridian = tzone[i].zmer * (PI/180);
403     return;
404     }
405     } while (tzone[i++].zname[0]);
406    
407     fprintf(stderr, "%s: unknown time zone: %s\n", progname, cp);
408     fprintf(stderr, "Known time zones:\n\t%s", tzone[0].zname);
409     for (i = 1; tzone[i].zname[0]; i++)
410     fprintf(stderr, " %s", tzone[i].zname);
411     putc('\n', stderr);
412     exit(1);
413 greg 1.1 }
414    
415    
416 schorsch 2.22 void
417     printhead( /* print command header */
418     register int ac,
419     register char **av
420     )
421 greg 1.1 {
422     putchar('#');
423     while (ac--) {
424     putchar(' ');
425     fputs(*av++, stdout);
426     }
427     putchar('\n');
428     }