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/* Copyright (c) 1991 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* Compute Glare Index given by program name: |
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* |
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* guth_dgr - Guth discomfort glare rating |
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* guth_vcp - Guth visual comfort probability |
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* cie_cgi - CIE Glare Index (1983) |
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* |
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* 12 April 1991 Greg Ward EPFL |
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*/ |
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|
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#include "standard.h" |
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#include "view.h" |
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|
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extern double erfc(); |
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|
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double posindex(); |
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int headline(); |
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|
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double direct(), guth_dgr(), guth_vcp(), cie_cgi(); |
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|
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struct named_func { |
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char *name; |
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double (*func)(); |
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} all_funcs[] = { |
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{"direct", direct}, |
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{"guth_dgr", guth_dgr}, |
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{"guth_vcp", guth_vcp}, |
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{"cie_cgi", cie_cgi}, |
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{NULL} |
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}; |
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|
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struct glare_src { |
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FVECT dir; /* source direction */ |
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double dom; /* solid angle */ |
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double lum; /* average luminance */ |
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struct glare_src *next; |
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} *all_srcs = NULL; |
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|
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struct glare_dir { |
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double ang; /* angle (in radians) */ |
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double indirect; /* indirect illuminance */ |
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struct glare_dir *next; |
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} *all_dirs = NULL; |
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|
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#define newp(type) (type *)malloc(sizeof(type)) |
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|
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char *progname; |
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int print_header = 1; |
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|
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VIEW midview = STDVIEW; |
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|
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int wrongformat = 0; |
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|
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|
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main(argc, argv) |
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int argc; |
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char *argv[]; |
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{ |
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extern char *rindex(); |
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struct named_func *funp; |
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char *progtail; |
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int i; |
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/* get program name */ |
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progname = argv[0]; |
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progtail = rindex(progname, '/'); /* final component */ |
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if (progtail == NULL) |
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progtail = progname; |
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else |
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progtail++; |
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/* get options */ |
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for (i = 1; i < argc && argv[i][0] == '-'; i++) |
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switch (argv[i][1]) { |
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case 't': |
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progtail = argv[++i]; |
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break; |
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case 'h': |
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print_header = 0; |
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break; |
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default: |
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goto userr; |
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} |
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if (i < argc-1) |
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goto userr; |
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if (i == argc-1) /* open file */ |
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if (freopen(argv[i], "r", stdin) == NULL) { |
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perror(argv[i]); |
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exit(1); |
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} |
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/* read header */ |
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getheader(stdin, headline, NULL); |
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if (wrongformat) { |
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fprintf(stderr, "%s: bad input format\n", progname); |
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exit(1); |
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} |
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if (print_header) { /* add to header */ |
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printargs(i, argv, stdout); |
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putchar('\n'); |
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} |
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/* set view */ |
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if (setview(&midview) != NULL) { |
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fprintf(stderr, "%s: bad view information in input\n", |
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progname); |
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exit(1); |
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} |
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/* get findglare data */ |
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read_input(); |
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/* find calculation */ |
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for (funp = all_funcs; funp->name != NULL; funp++) |
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if (!strcmp(funp->name, progtail)) { |
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print_values(funp->func); |
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exit(0); /* we're done */ |
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} |
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/* invalid function */ |
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fprintf(stderr, "%s: unknown function!\n", progtail); |
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exit(1); |
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userr: |
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fprintf(stderr, "Usage: %s [-t type][-h] [input]\n", progname); |
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exit(1); |
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} |
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|
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|
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headline(s) /* get line from header */ |
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char *s; |
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{ |
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char fmt[32]; |
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|
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if (print_header) /* copy to output */ |
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fputs(s, stdout); |
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if (!strncmp(s, VIEWSTR, VIEWSTRL)) |
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sscanview(&midview, s+VIEWSTRL); |
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else if (isformat(s)) { |
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formatval(fmt, s); |
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wrongformat = strcmp(fmt, "ascii"); |
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} |
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} |
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|
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|
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read_input() /* read glare sources from stdin */ |
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{ |
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#define S_SEARCH 0 |
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#define S_SOURCE 1 |
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#define S_DIREC 2 |
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int state = S_SEARCH; |
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char buf[128]; |
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register struct glare_src *gs; |
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register struct glare_dir *gd; |
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|
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while (fgets(buf, sizeof(buf), stdin) != NULL) |
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switch (state) { |
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case S_SEARCH: |
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if (!strcmp(buf, "BEGIN glare source\n")) |
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state = S_SOURCE; |
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else if (!strcmp(buf, "BEGIN indirect illuminance\n")) |
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state = S_DIREC; |
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break; |
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case S_SOURCE: |
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if (!strncmp(buf, "END", 3)) { |
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state = S_SEARCH; |
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break; |
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} |
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if ((gs = newp(struct glare_src)) == NULL) |
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goto memerr; |
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if (sscanf(buf, "%lf %lf %lf %lf %lf", |
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&gs->dir[0], &gs->dir[1], &gs->dir[2], |
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&gs->dom, &gs->lum) != 5) |
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goto readerr; |
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normalize(gs->dir); |
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gs->next = all_srcs; |
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all_srcs = gs; |
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break; |
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case S_DIREC: |
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if (!strncmp(buf, "END", 3)) { |
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state = S_SEARCH; |
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break; |
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} |
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if ((gd = newp(struct glare_dir)) == NULL) |
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goto memerr; |
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if (sscanf(buf, "%lf %lf", |
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&gd->ang, &gd->indirect) != 2) |
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goto readerr; |
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gd->ang *= PI/180.0; /* convert to radians */ |
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gd->next = all_dirs; |
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all_dirs = gd; |
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break; |
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} |
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return; |
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memerr: |
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perror(progname); |
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exit(1); |
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readerr: |
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fprintf(stderr, "%s: read error on input\n", progname); |
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exit(1); |
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#undef S_SEARCH |
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#undef S_SOURCE |
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#undef S_DIREC |
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} |
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|
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|
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print_values(funp) /* print out calculations */ |
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double (*funp)(); |
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{ |
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register struct glare_dir *gd; |
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|
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for (gd = all_dirs; gd != NULL; gd = gd->next) |
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printf("%f\t%f\n", gd->ang*(180.0/PI), (*funp)(gd)); |
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} |
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|
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|
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double |
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direct(gd) /* compute direct illuminance */ |
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struct glare_dir *gd; |
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{ |
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FVECT mydir; |
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double d, dval; |
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register struct glare_src *gs; |
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|
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spinvector(mydir, midview.vdir, midview.vup, gd->ang); |
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dval = 0.0; |
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for (gs = all_srcs; gs != NULL; gs = gs->next) { |
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d = DOT(mydir,gs->dir); |
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if (d > FTINY) |
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dval += d * gs->dom * gs->lum; |
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} |
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return(dval); |
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} |
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|
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|
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/* |
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* posindex - compute glare position index from: |
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* |
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* Source Direction |
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* View Direction |
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* View Up Direction |
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* |
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* All vectors are assumed to be normalized. |
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* This function is an implementation of the method proposed by |
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* Robert Levin in his 1975 JIES article. |
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* This calculation presumes the view direction and up vectors perpendicular. |
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* We return a value less than zero for improper positions. |
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*/ |
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|
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double |
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posindex(sd, vd, vu) /* compute position index */ |
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FVECT sd, vd, vu; |
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{ |
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double sigma, tau; |
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double d; |
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|
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d = DOT(sd,vd); |
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if (d <= 0.0) |
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return(-1.0); |
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if (d >= 1.0) |
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return(1.0); |
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sigma = acos(d) * (180./PI); |
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d = DOT(sd,vu)/sqrt(1.0-d*d); |
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if (d >= 1.0) |
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tau = 0.0; |
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else |
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tau = acos(d) * (180./PI); |
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return( exp( sigma*( (35.2 - tau*.31889 - 1.22*exp(-.22222*tau))*1e-3 |
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+ sigma*(21. + tau*(.26667 + tau*-.002963))*1e-5 ) |
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) ); |
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} |
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|
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|
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double |
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guth_dgr(gd) /* compute Guth discomfort glare rating */ |
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struct glare_dir *gd; |
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{ |
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#define q(w) (20.4*w+1.52*pow(w,.2)-.075) |
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register struct glare_src *gs; |
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FVECT mydir; |
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double p; |
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double sum; |
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double wtot, brsum; |
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int n; |
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|
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spinvector(mydir, midview.vdir, midview.vup, gd->ang); |
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sum = wtot = brsum = 0.0; n = 0; |
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for (gs = all_srcs; gs != NULL; gs = gs->next) { |
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p = posindex(gs->dir, mydir, midview.vup); |
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if (p <= FTINY) |
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continue; |
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sum += gs->lum * q(gs->dom) / p; |
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brsum += gs->lum * gs->dom; |
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wtot += gs->dom; |
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n++; |
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} |
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if (n == 0) |
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return(0.0); |
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|
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return( pow(.5*sum/pow((brsum+(5.-wtot)*gd->indirect/PI)/5.,.44), |
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pow((double)n, -.0914) ) ); |
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#undef q |
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} |
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|
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|
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extern double erf(), erfc(); |
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|
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#ifndef M_SQRT2 |
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#define M_SQRT2 1.41421356237309504880 |
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#endif |
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|
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#define norm_integral(z) (1.-.5*erfc((z)/M_SQRT2)) |
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|
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|
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double |
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guth_vcp(gd) /* compute Guth visual comfort probability */ |
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struct glare_dir *gd; |
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{ |
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double dgr; |
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|
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dgr = guth_dgr(gd); |
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if (dgr <= FTINY) |
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return(100.0); |
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return(100.*norm_integral(6.374-1.3227*log(dgr))); |
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} |
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|
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|
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double |
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cie_cgi(gd) /* compute CIE Glare Index */ |
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struct glare_dir *gd; |
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{ |
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register struct glare_src *gs; |
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FVECT mydir; |
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double dillum; |
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double p; |
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double sum; |
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|
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spinvector(mydir, midview.vdir, midview.vup, gd->ang); |
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sum = 0.0; |
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for (gs = all_srcs; gs != NULL; gs = gs->next) { |
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p = posindex(gs->dir, mydir, midview.vup); |
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if (p <= FTINY) |
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continue; |
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sum += gs->lum*gs->lum * gs->dom / (p*p); |
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} |
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if (sum <= FTINY) |
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return(0.0); |
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dillum = direct(gd); |
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return(8.*log10(2.*sum*(1.+dillum/500.)/(dillum+gd->indirect))); |
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} |
