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root/radiance/ray/src/gen/gendaymtx.c
Revision: 2.18
Committed: Sun Oct 26 17:37:34 2014 UTC (9 years, 5 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad4R2P2
Changes since 2.17: +2 -2 lines
Log Message:
Fixed another warning

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: gendaymtx.c,v 2.17 2014/10/26 17:35:53 greg Exp $";
3 #endif
4 /*
5 * gendaymtx.c
6 *
7 * Generate a daylight matrix based on Perez Sky Model.
8 *
9 * Most of this code is borrowed (see copyright below) from Ian Ashdown's
10 * excellent re-implementation of Jean-Jacques Delaunay's gendaylit.c
11 *
12 * Created by Greg Ward on 1/16/13.
13 */
14
15 /*********************************************************************
16 *
17 * H32_gendaylit.CPP - Perez Sky Model Calculation
18 *
19 * Version: 1.00A
20 *
21 * History: 09/10/01 - Created.
22 * 11/10/08 - Modified for Unix compilation.
23 * 11/10/12 - Fixed conditional __max directive.
24 * 1/11/13 - Tweaks and optimizations (G.Ward)
25 *
26 * Compilers: Microsoft Visual C/C++ Professional V10.0
27 *
28 * Author: Ian Ashdown, P.Eng.
29 * byHeart Consultants Limited
30 * 620 Ballantree Road
31 * West Vancouver, B.C.
32 * Canada V7S 1W3
33 * e-mail: [email protected]
34 *
35 * References: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R.
36 * Stewart. 1990. ìModeling Daylight Availability and
37 * Irradiance Components from Direct and Global
38 * Irradiance,î Solar Energy 44(5):271-289.
39 *
40 * Perez, R., R. Seals, and J. Michalsky. 1993.
41 * ìAll-Weather Model for Sky Luminance Distribution -
42 * Preliminary Configuration and Validation,î Solar Energy
43 * 50(3):235-245.
44 *
45 * Perez, R., R. Seals, and J. Michalsky. 1993. "ERRATUM to
46 * All-Weather Model for Sky Luminance Distribution -
47 * Preliminary Configuration and Validation,î Solar Energy
48 * 51(5):423.
49 *
50 * NOTE: This program is a completely rewritten version of
51 * gendaylit.c written by Jean-Jacques Delaunay (1994).
52 *
53 * Copyright 2009-2012 byHeart Consultants Limited. All rights
54 * reserved.
55 *
56 * Redistribution and use in source and binary forms, with or without
57 * modification, are permitted for personal and commercial purposes
58 * provided that redistribution of source code must retain the above
59 * copyright notice, this list of conditions and the following
60 * disclaimer:
61 *
62 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
63 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
64 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
65 * DISCLAIMED. IN NO EVENT SHALL byHeart Consultants Limited OR
66 * ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
67 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
68 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
69 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
70 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
71 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
72 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
73 * POSSIBILITY OF SUCH DAMAGE.
74 *
75 *********************************************************************/
76
77 /* Zenith is along the Z-axis */
78 /* X-axis points east */
79 /* Y-axis points north */
80 /* azimuth is measured as degrees or radians east of North */
81
82 /* Include files */
83 #define _USE_MATH_DEFINES
84 #include <stdio.h>
85 #include <stdlib.h>
86 #include <string.h>
87 #include <ctype.h>
88 #include "rtmath.h"
89 #include "platform.h"
90 #include "color.h"
91 #include "resolu.h"
92
93 char *progname; /* Program name */
94 char errmsg[128]; /* Error message buffer */
95 const double DC_SolarConstantE = 1367.0; /* Solar constant W/m^2 */
96 const double DC_SolarConstantL = 127.5; /* Solar constant klux */
97
98 double altitude; /* Solar altitude (radians) */
99 double azimuth; /* Solar azimuth (radians) */
100 double apwc; /* Atmospheric precipitable water content */
101 double dew_point = 11.0; /* Surface dew point temperature (deg. C) */
102 double diff_illum; /* Diffuse illuminance */
103 double diff_irrad; /* Diffuse irradiance */
104 double dir_illum; /* Direct illuminance */
105 double dir_irrad; /* Direct irradiance */
106 int julian_date; /* Julian date */
107 double perez_param[5]; /* Perez sky model parameters */
108 double sky_brightness; /* Sky brightness */
109 double sky_clearness; /* Sky clearness */
110 double solar_rad; /* Solar radiance */
111 double sun_zenith; /* Sun zenith angle (radians) */
112 int input = 0; /* Input type */
113 int output = 0; /* Output type */
114
115 extern double dmax( double, double );
116 extern double CalcAirMass();
117 extern double CalcDiffuseIllumRatio( int );
118 extern double CalcDiffuseIrradiance();
119 extern double CalcDirectIllumRatio( int );
120 extern double CalcDirectIrradiance();
121 extern double CalcEccentricity();
122 extern double CalcPrecipWater( double );
123 extern double CalcRelHorzIllum( float *parr );
124 extern double CalcRelLuminance( double, double );
125 extern double CalcSkyBrightness();
126 extern double CalcSkyClearness();
127 extern int CalcSkyParamFromIllum();
128 extern int GetCategoryIndex();
129 extern void CalcPerezParam( double, double, double, int );
130 extern void CalcSkyPatchLumin( float *parr );
131 extern void ComputeSky( float *parr );
132
133 /* Degrees into radians */
134 #define DegToRad(deg) ((deg)*(PI/180.))
135
136 /* Radiuans into degrees */
137 #define RadToDeg(rad) ((rad)*(180./PI))
138
139
140 /* Perez sky model coefficients */
141
142 /* Reference: Perez, R., R. Seals, and J. Michalsky, 1993. "All- */
143 /* Weather Model for Sky Luminance Distribution - */
144 /* Preliminary Configuration and Validation," Solar */
145 /* Energy 50(3):235-245, Table 1. */
146
147 static const double PerezCoeff[8][20] =
148 {
149 /* Sky clearness (epsilon): 1.000 to 1.065 */
150 { 1.3525, -0.2576, -0.2690, -1.4366, -0.7670,
151 0.0007, 1.2734, -0.1233, 2.8000, 0.6004,
152 1.2375, 1.0000, 1.8734, 0.6297, 0.9738,
153 0.2809, 0.0356, -0.1246, -0.5718, 0.9938 },
154 /* Sky clearness (epsilon): 1.065 to 1.230 */
155 { -1.2219, -0.7730, 1.4148, 1.1016, -0.2054,
156 0.0367, -3.9128, 0.9156, 6.9750, 0.1774,
157 6.4477, -0.1239, -1.5798, -0.5081, -1.7812,
158 0.1080, 0.2624, 0.0672, -0.2190, -0.4285 },
159 /* Sky clearness (epsilon): 1.230 to 1.500 */
160 { -1.1000, -0.2515, 0.8952, 0.0156, 0.2782,
161 -0.1812, - 4.5000, 1.1766, 24.7219, -13.0812,
162 -37.7000, 34.8438, -5.0000, 1.5218, 3.9229,
163 -2.6204, -0.0156, 0.1597, 0.4199, -0.5562 },
164 /* Sky clearness (epsilon): 1.500 to 1.950 */
165 { -0.5484, -0.6654, -0.2672, 0.7117, 0.7234,
166 -0.6219, -5.6812, 2.6297, 33.3389, -18.3000,
167 -62.2500, 52.0781, -3.5000, 0.0016, 1.1477,
168 0.1062, 0.4659, -0.3296, -0.0876, -0.0329 },
169 /* Sky clearness (epsilon): 1.950 to 2.800 */
170 { -0.6000, -0.3566, -2.5000, 2.3250, 0.2937,
171 0.0496, -5.6812, 1.8415, 21.0000, -4.7656 ,
172 -21.5906, 7.2492, -3.5000, -0.1554, 1.4062,
173 0.3988, 0.0032, 0.0766, -0.0656, -0.1294 },
174 /* Sky clearness (epsilon): 2.800 to 4.500 */
175 { -1.0156, -0.3670, 1.0078, 1.4051, 0.2875,
176 -0.5328, -3.8500, 3.3750, 14.0000, -0.9999,
177 -7.1406, 7.5469, -3.4000, -0.1078, -1.0750,
178 1.5702, -0.0672, 0.4016, 0.3017, -0.4844 },
179 /* Sky clearness (epsilon): 4.500 to 6.200 */
180 { -1.0000, 0.0211, 0.5025, -0.5119, -0.3000,
181 0.1922, 0.7023, -1.6317, 19.0000, -5.0000,
182 1.2438, -1.9094, -4.0000, 0.0250, 0.3844,
183 0.2656, 1.0468, -0.3788, -2.4517, 1.4656 },
184 /* Sky clearness (epsilon): 6.200 to ... */
185 { -1.0500, 0.0289, 0.4260, 0.3590, -0.3250,
186 0.1156, 0.7781, 0.0025, 31.0625, -14.5000,
187 -46.1148, 55.3750, -7.2312, 0.4050, 13.3500,
188 0.6234, 1.5000, -0.6426, 1.8564, 0.5636 }
189 };
190
191 /* Perez irradiance component model coefficients */
192
193 /* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
194 /* Stewart. 1990. ìModeling Daylight Availability and */
195 /* Irradiance Components from Direct and Global */
196 /* Irradiance,î Solar Energy 44(5):271-289. */
197
198 typedef struct
199 {
200 double lower; /* Lower bound */
201 double upper; /* Upper bound */
202 } CategoryBounds;
203
204 /* Perez sky clearness (epsilon) categories (Table 1) */
205 static const CategoryBounds SkyClearCat[8] =
206 {
207 { 1.000, 1.065 }, /* Overcast */
208 { 1.065, 1.230 },
209 { 1.230, 1.500 },
210 { 1.500, 1.950 },
211 { 1.950, 2.800 },
212 { 2.800, 4.500 },
213 { 4.500, 6.200 },
214 { 6.200, 12.01 } /* Clear */
215 };
216
217 /* Luminous efficacy model coefficients */
218 typedef struct
219 {
220 double a;
221 double b;
222 double c;
223 double d;
224 } ModelCoeff;
225
226 /* Diffuse luminous efficacy model coefficients (Table 4, Eqn. 7) */
227 static const ModelCoeff DiffuseLumEff[8] =
228 {
229 { 97.24, -0.46, 12.00, -8.91 },
230 { 107.22, 1.15, 0.59, -3.95 },
231 { 104.97, 2.96, -5.53, -8.77 },
232 { 102.39, 5.59, -13.95, -13.90 },
233 { 100.71, 5.94, -22.75, -23.74 },
234 { 106.42, 3.83, -36.15, -28.83 },
235 { 141.88, 1.90, -53.24, -14.03 },
236 { 152.23, 0.35, -45.27, -7.98 }
237 };
238
239 /* Direct luminous efficacy model coefficients (Table 4, Eqn. 8) */
240 static const ModelCoeff DirectLumEff[8] =
241 {
242 { 57.20, -4.55, -2.98, 117.12 },
243 { 98.99, -3.46, -1.21, 12.38 },
244 { 109.83, -4.90, -1.71, -8.81 },
245 { 110.34, -5.84, -1.99, -4.56 },
246 { 106.36, -3.97, -1.75, -6.16 },
247 { 107.19, -1.25, -1.51, -26.73 },
248 { 105.75, 0.77, -1.26, -34.44 },
249 { 101.18, 1.58, -1.10, -8.29 }
250 };
251
252 #ifndef NSUNPATCH
253 #define NSUNPATCH 4 /* max. # patches to spread sun into */
254 #endif
255
256 extern int jdate(int month, int day);
257 extern double stadj(int jd);
258 extern double sdec(int jd);
259 extern double salt(double sd, double st);
260 extern double sazi(double sd, double st);
261 /* sun calculation constants */
262 extern double s_latitude;
263 extern double s_longitude;
264 extern double s_meridian;
265
266 int nsuns = NSUNPATCH; /* number of sun patches to use */
267 double fixed_sun_sa = -1; /* fixed solid angle per sun? */
268
269 int verbose = 0; /* progress reports to stderr? */
270
271 int outfmt = 'a'; /* output format */
272
273 int rhsubdiv = 1; /* Reinhart sky subdivisions */
274
275 COLOR skycolor = {.96, 1.004, 1.118}; /* sky coloration */
276 COLOR suncolor = {1., 1., 1.}; /* sun color */
277 COLOR grefl = {.2, .2, .2}; /* ground reflectance */
278
279 int nskypatch; /* number of Reinhart patches */
280 float *rh_palt; /* sky patch altitudes (radians) */
281 float *rh_pazi; /* sky patch azimuths (radians) */
282 float *rh_dom; /* sky patch solid angle (sr) */
283
284 #define vector(v,alt,azi) ( (v)[1] = tcos(alt), \
285 (v)[0] = (v)[1]*tsin(azi), \
286 (v)[1] *= tcos(azi), \
287 (v)[2] = tsin(alt) )
288
289 #define rh_vector(v,i) vector(v,rh_palt[i],rh_pazi[i])
290
291 #define rh_cos(i) tsin(rh_palt[i])
292
293 extern int rh_init(void);
294 extern float * resize_dmatrix(float *mtx_data, int nsteps, int npatch);
295 extern void AddDirect(float *parr);
296
297
298 static const char *
299 getfmtname(int fmt)
300 {
301 switch (fmt) {
302 case 'a':
303 return("ascii");
304 case 'f':
305 return("float");
306 case 'd':
307 return("double");
308 }
309 return("unknown");
310 }
311
312
313 int
314 main(int argc, char *argv[])
315 {
316 char buf[256];
317 int doheader = 1; /* output header? */
318 double rotation = 0; /* site rotation (degrees) */
319 double elevation; /* site elevation (meters) */
320 int dir_is_horiz; /* direct is meas. on horizontal? */
321 float *mtx_data = NULL; /* our matrix data */
322 int ntsteps = 0; /* number of rows in matrix */
323 int step_alloc = 0;
324 int last_monthly = 0; /* month of last report */
325 int mo, da; /* month (1-12) and day (1-31) */
326 double hr; /* hour (local standard time) */
327 double dir, dif; /* direct and diffuse values */
328 int mtx_offset;
329 int i, j;
330
331 progname = argv[0];
332 /* get options */
333 for (i = 1; i < argc && argv[i][0] == '-'; i++)
334 switch (argv[i][1]) {
335 case 'g': /* ground reflectance */
336 grefl[0] = atof(argv[++i]);
337 grefl[1] = atof(argv[++i]);
338 grefl[2] = atof(argv[++i]);
339 break;
340 case 'v': /* verbose progress reports */
341 verbose++;
342 break;
343 case 'h': /* turn off header */
344 doheader = 0;
345 break;
346 case 'o': /* output format */
347 switch (argv[i][2]) {
348 case 'f':
349 case 'd':
350 case 'a':
351 outfmt = argv[i][2];
352 break;
353 default:
354 goto userr;
355 }
356 break;
357 case 'O': /* output type */
358 switch (argv[i][2]) {
359 case '0':
360 output = 0;
361 break;
362 case '1':
363 output = 1;
364 break;
365 default:
366 goto userr;
367 }
368 if (argv[i][3])
369 goto userr;
370 break;
371 case 'm': /* Reinhart subdivisions */
372 rhsubdiv = atoi(argv[++i]);
373 break;
374 case 'c': /* sky color */
375 skycolor[0] = atof(argv[++i]);
376 skycolor[1] = atof(argv[++i]);
377 skycolor[2] = atof(argv[++i]);
378 break;
379 case 'd': /* solar (direct) only */
380 skycolor[0] = skycolor[1] = skycolor[2] = 0;
381 if (suncolor[1] <= 1e-4)
382 suncolor[0] = suncolor[1] = suncolor[2] = 1;
383 break;
384 case 's': /* sky only (no direct) */
385 suncolor[0] = suncolor[1] = suncolor[2] = 0;
386 if (skycolor[1] <= 1e-4)
387 skycolor[0] = skycolor[1] = skycolor[2] = 1;
388 break;
389 case 'r': /* rotate distribution */
390 if (argv[i][2] && argv[i][2] != 'z')
391 goto userr;
392 rotation = atof(argv[++i]);
393 break;
394 case '5': /* 5-phase calculation */
395 nsuns = 1;
396 fixed_sun_sa = 6.797e-05;
397 break;
398 default:
399 goto userr;
400 }
401 if (i < argc-1)
402 goto userr;
403 if (i == argc-1 && freopen(argv[i], "r", stdin) == NULL) {
404 fprintf(stderr, "%s: cannot open '%s' for input\n",
405 progname, argv[i]);
406 exit(1);
407 }
408 if (verbose) {
409 if (i == argc-1)
410 fprintf(stderr, "%s: reading weather tape '%s'\n",
411 progname, argv[i]);
412 else
413 fprintf(stderr, "%s: reading weather tape from <stdin>\n",
414 progname);
415 }
416 /* read weather tape header */
417 if (scanf("place %[^\r\n] ", buf) != 1)
418 goto fmterr;
419 if (scanf("latitude %lf\n", &s_latitude) != 1)
420 goto fmterr;
421 if (scanf("longitude %lf\n", &s_longitude) != 1)
422 goto fmterr;
423 if (scanf("time_zone %lf\n", &s_meridian) != 1)
424 goto fmterr;
425 if (scanf("site_elevation %lf\n", &elevation) != 1)
426 goto fmterr;
427 if (scanf("weather_data_file_units %d\n", &input) != 1)
428 goto fmterr;
429 switch (input) { /* translate units */
430 case 1:
431 input = 1; /* radiometric quantities */
432 dir_is_horiz = 0; /* direct is perpendicular meas. */
433 break;
434 case 2:
435 input = 1; /* radiometric quantities */
436 dir_is_horiz = 1; /* solar measured horizontally */
437 break;
438 case 3:
439 input = 2; /* photometric quantities */
440 dir_is_horiz = 0; /* direct is perpendicular meas. */
441 break;
442 default:
443 goto fmterr;
444 }
445 rh_init(); /* initialize sky patches */
446 if (verbose) {
447 fprintf(stderr, "%s: location '%s'\n", progname, buf);
448 fprintf(stderr, "%s: (lat,long)=(%.1f,%.1f) degrees north, west\n",
449 progname, s_latitude, s_longitude);
450 fprintf(stderr, "%s: %d sky patches per time step\n",
451 progname, nskypatch);
452 if (rotation != 0)
453 fprintf(stderr, "%s: rotating output %.0f degrees\n",
454 progname, rotation);
455 }
456 /* convert quantities to radians */
457 s_latitude = DegToRad(s_latitude);
458 s_longitude = DegToRad(s_longitude);
459 s_meridian = DegToRad(s_meridian);
460 /* process each time step in tape */
461 while (scanf("%d %d %lf %lf %lf\n", &mo, &da, &hr, &dir, &dif) == 5) {
462 double sda, sta;
463 /* make space for next time step */
464 mtx_offset = 3*nskypatch*ntsteps++;
465 if (ntsteps > step_alloc) {
466 step_alloc += (step_alloc>>1) + ntsteps + 7;
467 mtx_data = resize_dmatrix(mtx_data, step_alloc, nskypatch);
468 }
469 if (dif <= 1e-4) {
470 memset(mtx_data+mtx_offset, 0, sizeof(float)*3*nskypatch);
471 continue;
472 }
473 if (verbose && mo != last_monthly)
474 fprintf(stderr, "%s: stepping through month %d...\n",
475 progname, last_monthly=mo);
476 /* compute solar position */
477 julian_date = jdate(mo, da);
478 sda = sdec(julian_date);
479 sta = stadj(julian_date);
480 altitude = salt(sda, hr+sta);
481 azimuth = sazi(sda, hr+sta) + PI - DegToRad(rotation);
482 /* convert measured values */
483 if (dir_is_horiz && altitude > 0.)
484 dir /= sin(altitude);
485 if (input == 1) {
486 dir_irrad = dir;
487 diff_irrad = dif;
488 } else /* input == 2 */ {
489 dir_illum = dir;
490 diff_illum = dif;
491 }
492 /* compute sky patch values */
493 ComputeSky(mtx_data+mtx_offset);
494 AddDirect(mtx_data+mtx_offset);
495 }
496 /* check for junk at end */
497 while ((i = fgetc(stdin)) != EOF)
498 if (!isspace(i)) {
499 fprintf(stderr, "%s: warning - unexpected data past EOT: ",
500 progname);
501 buf[0] = i; buf[1] = '\0';
502 fgets(buf+1, sizeof(buf)-1, stdin);
503 fputs(buf, stderr); fputc('\n', stderr);
504 break;
505 }
506 /* write out matrix */
507 if (outfmt != 'a')
508 SET_FILE_BINARY(stdout);
509 #ifdef getc_unlocked
510 flockfile(stdout);
511 #endif
512 if (verbose)
513 fprintf(stderr, "%s: writing %smatrix with %d time steps...\n",
514 progname, outfmt=='a' ? "" : "binary ", ntsteps);
515 if (doheader) {
516 newheader("RADIANCE", stdout);
517 printargs(argc, argv, stdout);
518 printf("LATLONG= %.8f %.8f\n", RadToDeg(s_latitude),
519 -RadToDeg(s_longitude));
520 printf("NROWS=%d\n", nskypatch);
521 printf("NCOLS=%d\n", ntsteps);
522 printf("NCOMP=3\n");
523 fputformat((char *)getfmtname(outfmt), stdout);
524 putchar('\n');
525 }
526 /* patches are rows (outer sort) */
527 for (i = 0; i < nskypatch; i++) {
528 mtx_offset = 3*i;
529 switch (outfmt) {
530 case 'a':
531 for (j = 0; j < ntsteps; j++) {
532 printf("%.3g %.3g %.3g\n", mtx_data[mtx_offset],
533 mtx_data[mtx_offset+1],
534 mtx_data[mtx_offset+2]);
535 mtx_offset += 3*nskypatch;
536 }
537 if (ntsteps > 1)
538 fputc('\n', stdout);
539 break;
540 case 'f':
541 for (j = 0; j < ntsteps; j++) {
542 fwrite(mtx_data+mtx_offset, sizeof(float), 3,
543 stdout);
544 mtx_offset += 3*nskypatch;
545 }
546 break;
547 case 'd':
548 for (j = 0; j < ntsteps; j++) {
549 double ment[3];
550 ment[0] = mtx_data[mtx_offset];
551 ment[1] = mtx_data[mtx_offset+1];
552 ment[2] = mtx_data[mtx_offset+2];
553 fwrite(ment, sizeof(double), 3, stdout);
554 mtx_offset += 3*nskypatch;
555 }
556 break;
557 }
558 if (ferror(stdout))
559 goto writerr;
560 }
561 if (fflush(stdout) == EOF)
562 goto writerr;
563 if (verbose)
564 fprintf(stderr, "%s: done.\n", progname);
565 exit(0);
566 userr:
567 fprintf(stderr, "Usage: %s [-v][-h][-d|-s][-r deg][-m N][-g r g b][-c r g b][-o{f|d}][-O{0|1}] [tape.wea]\n",
568 progname);
569 exit(1);
570 fmterr:
571 fprintf(stderr, "%s: input weather tape format error\n", progname);
572 exit(1);
573 writerr:
574 fprintf(stderr, "%s: write error on output\n", progname);
575 exit(1);
576 }
577
578 /* Return maximum of two doubles */
579 double dmax( double a, double b )
580 { return (a > b) ? a : b; }
581
582 /* Compute sky patch radiance values (modified by GW) */
583 void
584 ComputeSky(float *parr)
585 {
586 int index; /* Category index */
587 double norm_diff_illum; /* Normalized diffuse illuimnance */
588 int i;
589
590 /* Calculate atmospheric precipitable water content */
591 apwc = CalcPrecipWater(dew_point);
592
593 /* Calculate sun zenith angle (don't let it dip below horizon) */
594 /* Also limit minimum angle to keep circumsolar off zenith */
595 if (altitude <= 0.0)
596 sun_zenith = DegToRad(90.0);
597 else if (altitude >= DegToRad(87.0))
598 sun_zenith = DegToRad(3.0);
599 else
600 sun_zenith = DegToRad(90.0) - altitude;
601
602 /* Compute the inputs for the calculation of the sky distribution */
603
604 if (input == 0) /* XXX never used */
605 {
606 /* Calculate irradiance */
607 diff_irrad = CalcDiffuseIrradiance();
608 dir_irrad = CalcDirectIrradiance();
609
610 /* Calculate illuminance */
611 index = GetCategoryIndex();
612 diff_illum = diff_irrad * CalcDiffuseIllumRatio(index);
613 dir_illum = dir_irrad * CalcDirectIllumRatio(index);
614 }
615 else if (input == 1)
616 {
617 sky_brightness = CalcSkyBrightness();
618 sky_clearness = CalcSkyClearness();
619
620 /* Limit sky clearness */
621 if (sky_clearness > 11.9)
622 sky_clearness = 11.9;
623
624 /* Limit sky brightness */
625 if (sky_brightness < 0.01)
626 sky_brightness = 0.01;
627
628 /* Calculate illuminance */
629 index = GetCategoryIndex();
630 diff_illum = diff_irrad * CalcDiffuseIllumRatio(index);
631 dir_illum = dir_irrad * CalcDirectIllumRatio(index);
632 }
633 else if (input == 2)
634 {
635 /* Calculate sky brightness and clearness from illuminance values */
636 index = CalcSkyParamFromIllum();
637 }
638
639 if (output == 1) { /* hack for solar radiance */
640 diff_illum = diff_irrad * WHTEFFICACY;
641 dir_illum = dir_irrad * WHTEFFICACY;
642 }
643
644 if (bright(skycolor) <= 1e-4) { /* 0 sky component? */
645 memset(parr, 0, sizeof(float)*3*nskypatch);
646 return;
647 }
648 /* Compute ground radiance (include solar contribution if any) */
649 parr[0] = diff_illum;
650 if (altitude > 0)
651 parr[0] += dir_illum * sin(altitude);
652 parr[2] = parr[1] = parr[0] *= (1./PI/WHTEFFICACY);
653 multcolor(parr, grefl);
654
655 /* Calculate Perez sky model parameters */
656 CalcPerezParam(sun_zenith, sky_clearness, sky_brightness, index);
657
658 /* Calculate sky patch luminance values */
659 CalcSkyPatchLumin(parr);
660
661 /* Calculate relative horizontal illuminance */
662 norm_diff_illum = CalcRelHorzIllum(parr);
663
664 /* Check for zero sky -- make uniform in that case */
665 if (norm_diff_illum <= FTINY) {
666 for (i = 1; i < nskypatch; i++)
667 setcolor(parr+3*i, 1., 1., 1.);
668 norm_diff_illum = PI;
669 }
670 /* Normalization coefficient */
671 norm_diff_illum = diff_illum / norm_diff_illum;
672
673 /* Apply to sky patches to get absolute radiance values */
674 for (i = 1; i < nskypatch; i++) {
675 scalecolor(parr+3*i, norm_diff_illum*(1./WHTEFFICACY));
676 multcolor(parr+3*i, skycolor);
677 }
678 }
679
680 /* Add in solar direct to nearest sky patches (GW) */
681 void
682 AddDirect(float *parr)
683 {
684 FVECT svec;
685 double near_dprod[NSUNPATCH];
686 int near_patch[NSUNPATCH];
687 double wta[NSUNPATCH], wtot;
688 int i, j, p;
689
690 if (dir_illum <= 1e-4 || bright(suncolor) <= 1e-4)
691 return;
692 /* identify nsuns closest patches */
693 if (nsuns > NSUNPATCH)
694 nsuns = NSUNPATCH;
695 else if (nsuns <= 0)
696 nsuns = 1;
697 for (i = nsuns; i--; )
698 near_dprod[i] = -1.;
699 vector(svec, altitude, azimuth);
700 for (p = 1; p < nskypatch; p++) {
701 FVECT pvec;
702 double dprod;
703 rh_vector(pvec, p);
704 dprod = DOT(pvec, svec);
705 for (i = 0; i < nsuns; i++)
706 if (dprod > near_dprod[i]) {
707 for (j = nsuns; --j > i; ) {
708 near_dprod[j] = near_dprod[j-1];
709 near_patch[j] = near_patch[j-1];
710 }
711 near_dprod[i] = dprod;
712 near_patch[i] = p;
713 break;
714 }
715 }
716 wtot = 0; /* weight by proximity */
717 for (i = nsuns; i--; )
718 wtot += wta[i] = 1./(1.002 - near_dprod[i]);
719 /* add to nearest patch radiances */
720 for (i = nsuns; i--; ) {
721 float *pdest = parr + 3*near_patch[i];
722 float val_add = wta[i] * dir_illum / (WHTEFFICACY * wtot);
723
724 val_add /= (fixed_sun_sa > 0) ? fixed_sun_sa
725 : rh_dom[near_patch[i]] ;
726 *pdest++ += val_add*suncolor[0];
727 *pdest++ += val_add*suncolor[1];
728 *pdest++ += val_add*suncolor[2];
729 }
730 }
731
732 /* Initialize Reinhart sky patch positions (GW) */
733 int
734 rh_init(void)
735 {
736 #define NROW 7
737 static const int tnaz[NROW] = {30, 30, 24, 24, 18, 12, 6};
738 const double alpha = (PI/2.)/(NROW*rhsubdiv + .5);
739 int p, i, j;
740 /* allocate patch angle arrays */
741 nskypatch = 0;
742 for (p = 0; p < NROW; p++)
743 nskypatch += tnaz[p];
744 nskypatch *= rhsubdiv*rhsubdiv;
745 nskypatch += 2;
746 rh_palt = (float *)malloc(sizeof(float)*nskypatch);
747 rh_pazi = (float *)malloc(sizeof(float)*nskypatch);
748 rh_dom = (float *)malloc(sizeof(float)*nskypatch);
749 if ((rh_palt == NULL) | (rh_pazi == NULL) | (rh_dom == NULL)) {
750 fprintf(stderr, "%s: out of memory in rh_init()\n", progname);
751 exit(1);
752 }
753 rh_palt[0] = -PI/2.; /* ground & zenith patches */
754 rh_pazi[0] = 0.;
755 rh_dom[0] = 2.*PI;
756 rh_palt[nskypatch-1] = PI/2.;
757 rh_pazi[nskypatch-1] = 0.;
758 rh_dom[nskypatch-1] = 2.*PI*(1. - cos(alpha*.5));
759 p = 1; /* "normal" patches */
760 for (i = 0; i < NROW*rhsubdiv; i++) {
761 const float ralt = alpha*(i + .5);
762 const int ninrow = tnaz[i/rhsubdiv]*rhsubdiv;
763 const float dom = 2.*PI*(sin(alpha*(i+1)) - sin(alpha*i)) /
764 (double)ninrow;
765 for (j = 0; j < ninrow; j++) {
766 rh_palt[p] = ralt;
767 rh_pazi[p] = 2.*PI * j / (double)ninrow;
768 rh_dom[p++] = dom;
769 }
770 }
771 return nskypatch;
772 #undef NROW
773 }
774
775 /* Resize daylight matrix (GW) */
776 float *
777 resize_dmatrix(float *mtx_data, int nsteps, int npatch)
778 {
779 if (mtx_data == NULL)
780 mtx_data = (float *)malloc(sizeof(float)*3*nsteps*npatch);
781 else
782 mtx_data = (float *)realloc(mtx_data,
783 sizeof(float)*3*nsteps*npatch);
784 if (mtx_data == NULL) {
785 fprintf(stderr, "%s: out of memory in resize_dmatrix(%d,%d)\n",
786 progname, nsteps, npatch);
787 exit(1);
788 }
789 return(mtx_data);
790 }
791
792 /* Determine category index */
793 int GetCategoryIndex()
794 {
795 int index; /* Loop index */
796
797 for (index = 0; index < 8; index++)
798 if ((sky_clearness >= SkyClearCat[index].lower) &&
799 (sky_clearness < SkyClearCat[index].upper))
800 break;
801
802 return index;
803 }
804
805 /* Calculate diffuse illuminance to diffuse irradiance ratio */
806
807 /* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
808 /* Stewart. 1990. ìModeling Daylight Availability and */
809 /* Irradiance Components from Direct and Global */
810 /* Irradiance,î Solar Energy 44(5):271-289, Eqn. 7. */
811
812 double CalcDiffuseIllumRatio( int index )
813 {
814 ModelCoeff const *pnle; /* Category coefficient pointer */
815
816 /* Get category coefficient pointer */
817 pnle = &(DiffuseLumEff[index]);
818
819 return pnle->a + pnle->b * apwc + pnle->c * cos(sun_zenith) +
820 pnle->d * log(sky_brightness);
821 }
822
823 /* Calculate direct illuminance to direct irradiance ratio */
824
825 /* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
826 /* Stewart. 1990. ìModeling Daylight Availability and */
827 /* Irradiance Components from Direct and Global */
828 /* Irradiance,î Solar Energy 44(5):271-289, Eqn. 8. */
829
830 double CalcDirectIllumRatio( int index )
831 {
832 ModelCoeff const *pnle; /* Category coefficient pointer */
833
834 /* Get category coefficient pointer */
835 pnle = &(DirectLumEff[index]);
836
837 /* Calculate direct illuminance from direct irradiance */
838
839 return dmax((pnle->a + pnle->b * apwc + pnle->c * exp(5.73 *
840 sun_zenith - 5.0) + pnle->d * sky_brightness),
841 0.0);
842 }
843
844 /* Calculate sky brightness */
845
846 /* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
847 /* Stewart. 1990. ìModeling Daylight Availability and */
848 /* Irradiance Components from Direct and Global */
849 /* Irradiance,î Solar Energy 44(5):271-289, Eqn. 2. */
850
851 double CalcSkyBrightness()
852 {
853 return diff_irrad * CalcAirMass() / (DC_SolarConstantE *
854 CalcEccentricity());
855 }
856
857 /* Calculate sky clearness */
858
859 /* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
860 /* Stewart. 1990. ìModeling Daylight Availability and */
861 /* Irradiance Components from Direct and Global */
862 /* Irradiance,î Solar Energy 44(5):271-289, Eqn. 1. */
863
864 double CalcSkyClearness()
865 {
866 double sz_cubed; /* Sun zenith angle cubed */
867
868 /* Calculate sun zenith angle cubed */
869 sz_cubed = sun_zenith*sun_zenith*sun_zenith;
870
871 return ((diff_irrad + dir_irrad) / diff_irrad + 1.041 *
872 sz_cubed) / (1.0 + 1.041 * sz_cubed);
873 }
874
875 /* Calculate diffuse horizontal irradiance from Perez sky brightness */
876
877 /* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
878 /* Stewart. 1990. ìModeling Daylight Availability and */
879 /* Irradiance Components from Direct and Global */
880 /* Irradiance,î Solar Energy 44(5):271-289, Eqn. 2 */
881 /* (inverse). */
882
883 double CalcDiffuseIrradiance()
884 {
885 return sky_brightness * DC_SolarConstantE * CalcEccentricity() /
886 CalcAirMass();
887 }
888
889 /* Calculate direct normal irradiance from Perez sky clearness */
890
891 /* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
892 /* Stewart. 1990. ìModeling Daylight Availability and */
893 /* Irradiance Components from Direct and Global */
894 /* Irradiance,î Solar Energy 44(5):271-289, Eqn. 1 */
895 /* (inverse). */
896
897 double CalcDirectIrradiance()
898 {
899 return CalcDiffuseIrradiance() * ((sky_clearness - 1.0) * (1 + 1.041
900 * sun_zenith*sun_zenith*sun_zenith));
901 }
902
903 /* Calculate sky brightness and clearness from illuminance values */
904 int CalcSkyParamFromIllum()
905 {
906 double test1 = 0.1;
907 double test2 = 0.1;
908 int counter = 0;
909 int index = 0; /* Category index */
910
911 /* Convert illuminance to irradiance */
912 diff_irrad = diff_illum * DC_SolarConstantE /
913 (DC_SolarConstantL * 1000.0);
914 dir_irrad = dir_illum * DC_SolarConstantE /
915 (DC_SolarConstantL * 1000.0);
916
917 /* Calculate sky brightness and clearness */
918 sky_brightness = CalcSkyBrightness();
919 sky_clearness = CalcSkyClearness();
920
921 /* Limit sky clearness */
922 if (sky_clearness > 12.0)
923 sky_clearness = 12.0;
924
925 /* Limit sky brightness */
926 if (sky_brightness < 0.01)
927 sky_brightness = 0.01;
928
929 while (((fabs(diff_irrad - test1) > 10.0) ||
930 (fabs(dir_irrad - test2) > 10.0)) && !(counter == 5))
931 {
932 test1 = diff_irrad;
933 test2 = dir_irrad;
934 counter++;
935
936 /* Convert illuminance to irradiance */
937 index = GetCategoryIndex();
938 diff_irrad = diff_illum / CalcDiffuseIllumRatio(index);
939 dir_irrad = dir_illum / CalcDirectIllumRatio(index);
940
941 /* Calculate sky brightness and clearness */
942 sky_brightness = CalcSkyBrightness();
943 sky_clearness = CalcSkyClearness();
944
945 /* Limit sky clearness */
946 if (sky_clearness > 12.0)
947 sky_clearness = 12.0;
948
949 /* Limit sky brightness */
950 if (sky_brightness < 0.01)
951 sky_brightness = 0.01;
952 }
953
954 return GetCategoryIndex();
955 }
956
957 /* Calculate relative luminance */
958
959 /* Reference: Perez, R., R. Seals, and J. Michalsky. 1993. */
960 /* ìAll-Weather Model for Sky Luminance Distribution - */
961 /* Preliminary Configuration and Validation,î Solar Energy */
962 /* 50(3):235-245, Eqn. 1. */
963
964 double CalcRelLuminance( double gamma, double zeta )
965 {
966 return (1.0 + perez_param[0] * exp(perez_param[1] / cos(zeta))) *
967 (1.0 + perez_param[2] * exp(perez_param[3] * gamma) +
968 perez_param[4] * cos(gamma) * cos(gamma));
969 }
970
971 /* Calculate Perez sky model parameters */
972
973 /* Reference: Perez, R., R. Seals, and J. Michalsky. 1993. */
974 /* ìAll-Weather Model for Sky Luminance Distribution - */
975 /* Preliminary Configuration and Validation,î Solar Energy */
976 /* 50(3):235-245, Eqns. 6 - 8. */
977
978 void CalcPerezParam( double sz, double epsilon, double delta,
979 int index )
980 {
981 double x[5][4]; /* Coefficents a, b, c, d, e */
982 int i, j; /* Loop indices */
983
984 /* Limit sky brightness */
985 if (epsilon > 1.065 && epsilon < 2.8)
986 {
987 if (delta < 0.2)
988 delta = 0.2;
989 }
990
991 /* Get Perez coefficients */
992 for (i = 0; i < 5; i++)
993 for (j = 0; j < 4; j++)
994 x[i][j] = PerezCoeff[index][4 * i + j];
995
996 if (index != 0)
997 {
998 /* Calculate parameter a, b, c, d and e (Eqn. 6) */
999 for (i = 0; i < 5; i++)
1000 perez_param[i] = x[i][0] + x[i][1] * sz + delta * (x[i][2] +
1001 x[i][3] * sz);
1002 }
1003 else
1004 {
1005 /* Parameters a, b and e (Eqn. 6) */
1006 perez_param[0] = x[0][0] + x[0][1] * sz + delta * (x[0][2] +
1007 x[0][3] * sz);
1008 perez_param[1] = x[1][0] + x[1][1] * sz + delta * (x[1][2] +
1009 x[1][3] * sz);
1010 perez_param[4] = x[4][0] + x[4][1] * sz + delta * (x[4][2] +
1011 x[4][3] * sz);
1012
1013 /* Parameter c (Eqn. 7) */
1014 perez_param[2] = exp(pow(delta * (x[2][0] + x[2][1] * sz),
1015 x[2][2])) - x[2][3];
1016
1017 /* Parameter d (Eqn. 8) */
1018 perez_param[3] = -exp(delta * (x[3][0] + x[3][1] * sz)) +
1019 x[3][2] + delta * x[3][3];
1020 }
1021 }
1022
1023 /* Calculate relative horizontal illuminance (modified by GW) */
1024
1025 /* Reference: Perez, R., R. Seals, and J. Michalsky. 1993. */
1026 /* ìAll-Weather Model for Sky Luminance Distribution - */
1027 /* Preliminary Configuration and Validation,î Solar Energy */
1028 /* 50(3):235-245, Eqn. 3. */
1029
1030 double CalcRelHorzIllum( float *parr )
1031 {
1032 int i;
1033 double rh_illum = 0.0; /* Relative horizontal illuminance */
1034
1035 for (i = 1; i < nskypatch; i++)
1036 rh_illum += parr[3*i+1] * rh_cos(i) * rh_dom[i];
1037
1038 return rh_illum;
1039 }
1040
1041 /* Calculate earth orbit eccentricity correction factor */
1042
1043 /* Reference: Sen, Z. 2008. Solar Energy Fundamental and Modeling */
1044 /* Techniques. Springer, p. 72. */
1045
1046 double CalcEccentricity()
1047 {
1048 double day_angle; /* Day angle (radians) */
1049 double E0; /* Eccentricity */
1050
1051 /* Calculate day angle */
1052 day_angle = (julian_date - 1.0) * (2.0 * PI / 365.0);
1053
1054 /* Calculate eccentricity */
1055 E0 = 1.00011 + 0.034221 * cos(day_angle) + 0.00128 * sin(day_angle)
1056 + 0.000719 * cos(2.0 * day_angle) + 0.000077 * sin(2.0 *
1057 day_angle);
1058
1059 return E0;
1060 }
1061
1062 /* Calculate atmospheric precipitable water content */
1063
1064 /* Reference: Perez, R., P. Ineichen, R. Seals, J. Michalsky, and R. */
1065 /* Stewart. 1990. ìModeling Daylight Availability and */
1066 /* Irradiance Components from Direct and Global */
1067 /* Irradiance,î Solar Energy 44(5):271-289, Eqn. 3. */
1068
1069 /* Note: The default surface dew point temperature is 11 deg. C */
1070 /* (52 deg. F). Typical values are: */
1071
1072 /* Celsius Fahrenheit Human Perception */
1073 /* > 24 > 75 Extremely uncomfortable */
1074 /* 21 - 24 70 - 74 Very humid */
1075 /* 18 - 21 65 - 69 Somewhat uncomfortable */
1076 /* 16 - 18 60 - 64 OK for most people */
1077 /* 13 - 16 55 - 59 Comfortable */
1078 /* 10 - 12 50 - 54 Very comfortable */
1079 /* < 10 < 49 A bit dry for some */
1080
1081 double CalcPrecipWater( double dpt )
1082 { return exp(0.07 * dpt - 0.075); }
1083
1084 /* Calculate relative air mass */
1085
1086 /* Reference: Kasten, F. 1966. "A New Table and Approximation Formula */
1087 /* for the Relative Optical Air Mass," Arch. Meteorol. */
1088 /* Geophys. Bioklimataol. Ser. B14, pp. 206-233. */
1089
1090 /* Note: More sophisticated relative air mass models are */
1091 /* available, but they differ significantly only for */
1092 /* sun zenith angles greater than 80 degrees. */
1093
1094 double CalcAirMass()
1095 {
1096 return (1.0 / (cos(sun_zenith) + 0.15 * pow(93.885 -
1097 RadToDeg(sun_zenith), -1.253)));
1098 }
1099
1100 /* Calculate Perez All-Weather sky patch luminances (modified by GW) */
1101
1102 /* NOTE: The sky patches centers are determined in accordance with the */
1103 /* BRE-IDMP sky luminance measurement procedures. (See for example */
1104 /* Mardaljevic, J. 2001. "The BRE-IDMP Dataset: A New Benchmark */
1105 /* for the Validation of Illuminance Prediction Techniques," */
1106 /* Lighting Research & Technology 33(2):117-136.) */
1107
1108 void CalcSkyPatchLumin( float *parr )
1109 {
1110 int i;
1111 double aas; /* Sun-sky point azimuthal angle */
1112 double sspa; /* Sun-sky point angle */
1113 double zsa; /* Zenithal sun angle */
1114
1115 for (i = 1; i < nskypatch; i++)
1116 {
1117 /* Calculate sun-sky point azimuthal angle */
1118 aas = fabs(rh_pazi[i] - azimuth);
1119
1120 /* Calculate zenithal sun angle */
1121 zsa = PI * 0.5 - rh_palt[i];
1122
1123 /* Calculate sun-sky point angle (Equation 8-20) */
1124 sspa = acos(cos(sun_zenith) * cos(zsa) + sin(sun_zenith) *
1125 sin(zsa) * cos(aas));
1126
1127 /* Calculate patch luminance */
1128 parr[3*i] = CalcRelLuminance(sspa, zsa);
1129 if (parr[3*i] < 0) parr[3*i] = 0;
1130 parr[3*i+2] = parr[3*i+1] = parr[3*i];
1131 }
1132 }