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 |
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/* |
5 |
|
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* gensky.c - program to generate sky functions. |
6 |
|
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* Our zenith is along the Z-axis, the X-axis |
7 |
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* points east, and the Y-axis points north. |
8 |
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* Radiance is in watts/steradian/sq. meter. |
9 |
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* |
10 |
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* 3/26/86 |
11 |
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*/ |
12 |
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13 |
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#include <stdio.h> |
14 |
greg |
2.20 |
#include <stdlib.h> |
15 |
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#include <string.h> |
16 |
greg |
1.1 |
#include <math.h> |
17 |
greg |
2.17 |
#include <ctype.h> |
18 |
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19 |
greg |
1.6 |
#include "color.h" |
20 |
greg |
1.1 |
|
21 |
schorsch |
2.22 |
extern int jdate(int month, int day); |
22 |
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extern double stadj(int jd); |
23 |
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extern double sdec(int jd); |
24 |
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extern double salt(double sd, double st); |
25 |
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extern double sazi(double sd, double st); |
26 |
greg |
1.1 |
|
27 |
greg |
2.17 |
#ifndef PI |
28 |
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#define PI 3.14159265358979323846 |
29 |
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#endif |
30 |
greg |
1.1 |
|
31 |
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#define DOT(v1,v2) (v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2]) |
32 |
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33 |
greg |
2.13 |
#define S_CLEAR 1 |
34 |
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#define S_OVER 2 |
35 |
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#define S_UNIF 3 |
36 |
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#define S_INTER 4 |
37 |
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38 |
schorsch |
2.21 |
#define overcast ((skytype==S_OVER)|(skytype==S_UNIF)) |
39 |
greg |
2.13 |
|
40 |
greg |
1.1 |
double normsc(); |
41 |
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/* sun calculation constants */ |
42 |
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extern double s_latitude; |
43 |
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extern double s_longitude; |
44 |
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extern double s_meridian; |
45 |
greg |
2.17 |
|
46 |
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#undef toupper |
47 |
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#define toupper(c) ((c) & ~0x20) /* ASCII trick to convert case */ |
48 |
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49 |
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/* European and North American zones */ |
50 |
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struct { |
51 |
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char zname[8]; /* time zone name (all caps) */ |
52 |
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float zmer; /* standard meridian */ |
53 |
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} tzone[] = { |
54 |
schorsch |
2.22 |
{"YST", 135}, {"YDT", 120}, |
55 |
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{"PST", 120}, {"PDT", 105}, |
56 |
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{"MST", 105}, {"MDT", 90}, |
57 |
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{"CST", 90}, {"CDT", 75}, |
58 |
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{"EST", 75}, {"EDT", 60}, |
59 |
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{"AST", 60}, {"ADT", 45}, |
60 |
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{"NST", 52.5}, {"NDT", 37.5}, |
61 |
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{"GMT", 0}, {"BST", -15}, |
62 |
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{"CET", -15}, {"CEST", -30}, |
63 |
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{"EET", -30}, {"EEST", -45}, |
64 |
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{"AST", -45}, {"ADT", -60}, |
65 |
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{"GST", -60}, {"GDT", -75}, |
66 |
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{"IST", -82.5}, {"IDT", -97.5}, |
67 |
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{"JST", -135}, {"NDT", -150}, |
68 |
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{"NZST", -180}, {"NZDT", -195}, |
69 |
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{"", 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 |
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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 |
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int u_zenith = 0; /* -1=irradiance, 1=radiance */ |
81 |
greg |
1.1 |
double turbidity = 2.75; |
82 |
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double gprefl = 0.2; |
83 |
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/* computed values */ |
84 |
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double sundir[3]; |
85 |
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double groundbr; |
86 |
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double F2; |
87 |
greg |
2.12 |
double solarbr = 0.0; |
88 |
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int u_solar = 0; /* -1=irradiance, 1=radiance */ |
89 |
greg |
1.1 |
|
90 |
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char *progname; |
91 |
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char errmsg[128]; |
92 |
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93 |
schorsch |
2.22 |
void computesky(void); |
94 |
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void printsky(void); |
95 |
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void printdefaults(void); |
96 |
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void userror(char *msg); |
97 |
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double normsc(void); |
98 |
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void cvthour(char *hs); |
99 |
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void printhead(register int ac, register char **av); |
100 |
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101 |
greg |
1.1 |
|
102 |
schorsch |
2.22 |
int |
103 |
greg |
1.1 |
main(argc, argv) |
104 |
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int argc; |
105 |
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char *argv[]; |
106 |
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{ |
107 |
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int i; |
108 |
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109 |
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progname = argv[0]; |
110 |
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if (argc == 2 && !strcmp(argv[1], "-defaults")) { |
111 |
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printdefaults(); |
112 |
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exit(0); |
113 |
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} |
114 |
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if (argc < 4) |
115 |
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userror("arg count"); |
116 |
greg |
2.3 |
if (!strcmp(argv[1], "-ang")) { |
117 |
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altitude = atof(argv[2]) * (PI/180); |
118 |
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azimuth = atof(argv[3]) * (PI/180); |
119 |
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month = 0; |
120 |
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} else { |
121 |
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month = atoi(argv[1]); |
122 |
greg |
2.6 |
if (month < 1 || month > 12) |
123 |
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userror("bad month"); |
124 |
greg |
2.3 |
day = atoi(argv[2]); |
125 |
greg |
2.6 |
if (day < 1 || day > 31) |
126 |
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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 |
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if (argv[i][0] == '-' || argv[i][0] == '+') |
131 |
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switch (argv[i][1]) { |
132 |
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case 's': |
133 |
greg |
2.13 |
skytype = S_CLEAR; |
134 |
greg |
1.1 |
dosun = argv[i][0] == '+'; |
135 |
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break; |
136 |
greg |
2.8 |
case 'r': |
137 |
greg |
2.12 |
case 'R': |
138 |
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u_solar = argv[i][1]=='R' ? -1 : 1; |
139 |
greg |
2.8 |
solarbr = atof(argv[++i]); |
140 |
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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 |
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skytype = S_UNIF; |
146 |
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break; |
147 |
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case 'i': |
148 |
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skytype = S_INTER; |
149 |
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dosun = argv[i][0] == '+'; |
150 |
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break; |
151 |
greg |
1.1 |
case 't': |
152 |
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turbidity = atof(argv[++i]); |
153 |
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break; |
154 |
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case 'b': |
155 |
greg |
2.12 |
case 'B': |
156 |
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u_zenith = argv[i][1]=='B' ? -1 : 1; |
157 |
greg |
1.1 |
zenithbr = atof(argv[++i]); |
158 |
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break; |
159 |
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case 'g': |
160 |
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gprefl = atof(argv[++i]); |
161 |
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break; |
162 |
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case 'a': |
163 |
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s_latitude = atof(argv[++i]) * (PI/180); |
164 |
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break; |
165 |
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case 'o': |
166 |
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s_longitude = atof(argv[++i]) * (PI/180); |
167 |
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break; |
168 |
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case 'm': |
169 |
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s_meridian = atof(argv[++i]) * (PI/180); |
170 |
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break; |
171 |
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default: |
172 |
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sprintf(errmsg, "unknown option: %s", argv[i]); |
173 |
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userror(errmsg); |
174 |
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} |
175 |
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else |
176 |
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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 |
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"%s: warning: %.1f hours btwn. standard meridian and longitude\n", |
181 |
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progname, (s_longitude-s_meridian)*12/PI); |
182 |
greg |
1.1 |
|
183 |
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printhead(argc, argv); |
184 |
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185 |
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computesky(); |
186 |
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printsky(); |
187 |
greg |
2.15 |
|
188 |
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exit(0); |
189 |
greg |
1.1 |
} |
190 |
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191 |
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192 |
schorsch |
2.22 |
void |
193 |
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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 |
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int jd; |
199 |
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double sd, st; |
200 |
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201 |
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jd = jdate(month, day); /* Julian date */ |
202 |
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sd = sdec(jd); /* solar declination */ |
203 |
greg |
2.5 |
if (tsolar) /* solar time */ |
204 |
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st = hour; |
205 |
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else |
206 |
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st = hour + stadj(jd); |
207 |
greg |
2.3 |
altitude = salt(sd, st); |
208 |
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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 |
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"%s: warning - sun too close to zenith, reducing altitude to 87 degrees\n", |
216 |
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progname); |
217 |
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printf( |
218 |
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"# warning - sun too close to zenith, reducing altitude to 87 degrees\n"); |
219 |
|
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altitude = 87.*PI/180.; |
220 |
greg |
2.3 |
} |
221 |
greg |
1.1 |
sundir[0] = -sin(azimuth)*cos(altitude); |
222 |
|
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sundir[1] = -cos(azimuth)*cos(altitude); |
223 |
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sundir[2] = sin(altitude); |
224 |
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|
225 |
greg |
2.12 |
/* Compute normalization factor */ |
226 |
greg |
2.13 |
switch (skytype) { |
227 |
|
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case S_UNIF: |
228 |
greg |
2.12 |
normfactor = 1.0; |
229 |
greg |
2.13 |
break; |
230 |
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case S_OVER: |
231 |
greg |
2.12 |
normfactor = 0.777778; |
232 |
greg |
2.13 |
break; |
233 |
|
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case S_CLEAR: |
234 |
greg |
2.12 |
F2 = 0.274*(0.91 + 10.0*exp(-3.0*(PI/2.0-altitude)) + |
235 |
|
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0.45*sundir[2]*sundir[2]); |
236 |
greg |
2.13 |
normfactor = normsc()/F2/PI; |
237 |
|
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break; |
238 |
|
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case S_INTER: |
239 |
|
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F2 = (2.739 + .9891*sin(.3119+2.6*altitude)) * |
240 |
|
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exp(-(PI/2.0-altitude)*(.4441+1.48*altitude)); |
241 |
|
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normfactor = normsc()/F2/PI; |
242 |
|
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break; |
243 |
greg |
2.12 |
} |
244 |
greg |
1.1 |
/* Compute zenith brightness */ |
245 |
greg |
2.12 |
if (u_zenith == -1) |
246 |
|
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zenithbr /= normfactor*PI; |
247 |
|
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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 |
|
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zenithbr = (zenithbr + 8.6*sundir[2] + .123)/2.0; |
254 |
greg |
2.12 |
if (zenithbr < 0.0) |
255 |
|
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zenithbr = 0.0; |
256 |
|
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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 |
|
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solarbr /= 6e-5*sundir[2]; |
265 |
greg |
2.13 |
else if (u_solar == 0) { |
266 |
greg |
2.12 |
solarbr = 1.5e9/SUNEFFICACY * |
267 |
|
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(1.147 - .147/(sundir[2]>.16?sundir[2]:.16)); |
268 |
greg |
2.13 |
if (skytype == S_INTER) |
269 |
|
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solarbr *= 0.15; /* fudge factor! */ |
270 |
|
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} |
271 |
greg |
2.12 |
groundbr += 6e-5/PI*solarbr*sundir[2]; |
272 |
|
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} else |
273 |
|
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dosun = 0; |
274 |
greg |
1.1 |
groundbr *= gprefl; |
275 |
|
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} |
276 |
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|
277 |
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|
278 |
schorsch |
2.22 |
void |
279 |
|
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printsky(void) /* print out sky */ |
280 |
greg |
1.1 |
{ |
281 |
|
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if (dosun) { |
282 |
|
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printf("\nvoid light solar\n"); |
283 |
|
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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 |
|
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printf("0\n0\n"); |
287 |
|
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printf("4 %f %f %f 0.5\n", sundir[0], sundir[1], sundir[2]); |
288 |
|
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} |
289 |
|
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|
290 |
|
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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 |
|
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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 |
|
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skytype, zenithbr, groundbr, F2, |
298 |
|
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sundir[0], sundir[1], sundir[2]); |
299 |
greg |
1.1 |
} |
300 |
|
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|
301 |
|
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|
302 |
schorsch |
2.22 |
void |
303 |
|
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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 |
|
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case S_INTER: |
313 |
|
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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 |
|
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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 |
|
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|
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 |
|
|
} |