src/gen/genssky.c

#include "color.h"
#ifndef lint
static const char RCSid[] =
    "$Id: genssky.c,v 2.6 2024/10/09 17:22:42 greg Exp $";
#endif
/* Main function for generating spectral sky */
/* Cloudy sky computed as weight average of clear and cie overcast sky */

#include "atmos.h"
#include "copyright.h"
#include "resolu.h"
#include "rtio.h"
#include <ctype.h>
#ifdef _WIN32
#include <windows.h>
#else
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#endif

char *progname;

const double ARCTIC_LAT = 67.;
const double TROPIC_LAT = 23.;
const int SUMMER_START = 4;
const int SUMMER_END = 9;
const double GNORM = 0.777778;

const double D65EFF = 203.; /* standard illuminant D65 */

/* Mean normalized relative daylight spectra where CCT = 6415K for overcast; */
const double D6415[NSSAMP] = {0.63231, 1.06171, 1.00779, 1.36423, 1.34133,
                              1.27258, 1.26276, 1.26352, 1.22201, 1.13246,
                              1.0434,  1.05547, 0.98212, 0.94445, 0.9722,
                              0.82387, 0.87853, 0.82559, 0.75111, 0.78925};

/* European and North American zones */
struct {
  char zname[8]; /* time zone name (all caps) */
  float zmer;    /* standard meridian */
} tzone[] = {{"YST", 135},   {"YDT", 120},   {"PST", 120},  {"PDT", 105},
             {"MST", 105},   {"MDT", 90},    {"CST", 90},   {"CDT", 75},
             {"EST", 75},    {"EDT", 60},    {"AST", 60},   {"ADT", 45},
             {"NST", 52.5},  {"NDT", 37.5},  {"GMT", 0},    {"BST", -15},
             {"CET", -15},   {"CEST", -30},  {"EET", -30},  {"EEST", -45},
             {"AST", -45},   {"ADT", -60},   {"GST", -60},  {"GDT", -75},
             {"IST", -82.5}, {"IDT", -97.5}, {"JST", -135}, {"NDT", -150},
             {"NZST", -180}, {"NZDT", -195}, {"", 0}};

static int make_directory(const char *path) {
#ifdef _WIN32
  if (CreateDirectory(path, NULL) || GetLastError() == ERROR_ALREADY_EXISTS) {
    return 1;
  }
  return 0;
#else
  if (mkdir(path, 0777) == 0 || errno == EEXIST) {
    return 1;
  }
  return 0;
#endif
}

inline static float deg2rad(float deg) { return deg * (PI / 180.); }

static int cvthour(char *hs, int *tsolar, double *hour) {
  char *cp = hs;
  int i, j;

  if ((*tsolar = *cp == '+'))
    cp++; /* solar time? */
  while (isdigit(*cp))
    cp++;
  if (*cp == ':')
    *hour = atoi(hs) + atoi(++cp) / 60.0;
  else {
    *hour = atof(hs);
    if (*cp == '.')
      cp++;
  }
  while (isdigit(*cp))
    cp++;
  if (!*cp)
    return (0);
  if (*tsolar || !isalpha(*cp)) {
    fprintf(stderr, "%s: bad time format: %s\n", progname, hs);
    exit(1);
  }
  i = 0;
  do {
    for (j = 0; cp[j]; j++)
      if (toupper(cp[j]) != tzone[i].zname[j])
        break;
    if (!cp[j] && !tzone[i].zname[j]) {
      s_meridian = tzone[i].zmer * (PI / 180);
      return (1);
    }
  } while (tzone[i++].zname[0]);

  fprintf(stderr, "%s: unknown time zone: %s\n", progname, cp);
  fprintf(stderr, "Known time zones:\n\t%s", tzone[0].zname);
  for (i = 1; tzone[i].zname[0]; i++)
    fprintf(stderr, " %s", tzone[i].zname);
  putc('\n', stderr);
  exit(1);
}

static void basename(const char *path, char *output, size_t outsize) {
  const char *last_slash = strrchr(path, '/');
  const char *last_backslash = strrchr(path, '\\');
  const char *filename = path;
  const char *last_dot;

  if (last_slash && last_backslash) {
    filename =
        (last_slash > last_backslash) ? last_slash + 1 : last_backslash + 1;
  } else if (last_slash) {
    filename = last_slash + 1;
  } else if (last_backslash) {
    filename = last_backslash + 1;
  }

  last_dot = strrchr(filename, '.');
  if (last_dot) {
    size_t length = last_dot - filename;
    if (length < outsize) {
      strncpy(output, filename, length);
      output[length] = '\0';
    } else {
      strncpy(output, filename, outsize - 1);
      output[outsize - 1] = '\0';
    }
  }
}

static char *join_paths(const char *path1, const char *path2) {
  size_t len1 = strlen(path1);
  size_t len2 = strlen(path2);
  int need_separator = (path1[len1 - 1] != DIRSEP);

  char *result = malloc(len1 + len2 + (need_separator ? 2 : 1));
  if (!result)
    return NULL;

  strcpy(result, path1);
  if (need_separator) {
    result[len1] = DIRSEP;
    len1++;
  }
  strcpy(result + len1, path2);

  return result;
}

static inline double wmean2(const double a, const double b, const double x) {
  return a * (1 - x) + b * x;
}

static inline double wmean(const double a, const double x, const double b,
                           const double y) {
  return (a * x + b * y) / (a + b);
}

static double get_overcast_zenith_brightness(const double sundir[3]) {
  double zenithbr;
  if (sundir[2] < 0) {
    zenithbr = 0;
  } else {
    zenithbr = (8.6 * sundir[2] + .123) * 1000.0 / D65EFF;
  }
  return zenithbr;
}

/* from gensky.c */
static double get_overcast_brightness(const double dz, const double zenithbr) {
  double groundbr = zenithbr * GNORM;
  return wmean(pow(dz + 1.01, 10), zenithbr * (1 + 2 * dz) / 3,
               pow(dz + 1.01, -10), groundbr);
}

static void write_header(const int argc, char **argv, const double cloud_cover,
                         const double grefl, const int res) {
  int i;
  printf("# ");
  for (i = 0; i < argc; i++) {
    printf("%s ", argv[i]);
  }
  printf("\n");
  printf(
      "#Cloud cover: %g\n#Ground reflectance: %g\n#Sky map resolution: %d\n\n",
      cloud_cover, grefl, res);
}

static void write_rad(const double *sun_radiance, const double intensity,
                      const FVECT sundir, const char *ddir,
                      const char *skyfile) {
  if (sundir[2] > 0) {
    printf("void spectrum sunrad\n0\n0\n22 380 780 ");
    int i;
    for (i = 0; i < NSSAMP; ++i) {
      printf("%.3f ", sun_radiance[i]);
    }
    printf("\n\nsunrad light solar\n0\n0\n3 %.1f %.1f %.1f\n\n", intensity,
           intensity, intensity);
    printf("solar source sun\n0\n0\n4 %f %f %f 0.533\n\n", sundir[0], sundir[1],
           sundir[2]);
  }
  printf("void specpict skyfunc\n5 noop %s . 'Atan2(Dy,Dx)/PI+1' "
         "'1-Acos(Dz)/PI'\n0\n0\n\n",
         skyfile);
}

static void write_hsr_header(FILE *fp, RESOLU *res) {
  float wvsplit[4] = {380, 480, 588, 780};
  newheader("RADIANCE", fp);
  fputncomp(NSSAMP, fp);
  fputwlsplit(wvsplit, fp);
  fputformat(SPECFMT, fp);
  fputc('\n', fp);
  fputsresolu(res, fp);
}

static inline float frac(float x) { return x - floor(x); }

int gen_spect_sky(DATARRAY *tau_clear, DATARRAY *scat_clear,
                  DATARRAY *scat1m_clear, DATARRAY *irrad_clear,
                  const double cloud_cover, const FVECT sundir,
                  const double grefl, const int res, const char *outname,
                  const char *ddir, const double dirnorm, const double difhor) {
  char skyfile[PATH_MAX];
  if (!snprintf(skyfile, sizeof(skyfile), "%s%c%s_sky.hsr", ddir, DIRSEP,
                outname)) {
    fprintf(stderr, "Error setting sky file name\n");
    return 0;
  };
  int xres = res;
  int yres = xres / 2;
  RESOLU rs = {PIXSTANDARD, xres, yres};
  FILE *skyfp = fopen(skyfile, "w");
  write_hsr_header(skyfp, &rs);

  CNDX[3] = NSSAMP;

  FVECT view_point = {0, 0, ER + 10};
  const double radius = VLEN(view_point);
  const double sun_ct = fdot(view_point, sundir) / radius;

  double overcast_zenithbr = get_overcast_zenith_brightness(sundir);
  double overcast_grndbr = overcast_zenithbr * GNORM;

  double dif_ratio = 1;
  if (difhor > 0) {
    DATARRAY *indirect_irradiance_clear = get_indirect_irradiance(irrad_clear, radius, sun_ct);
    double overcast_ghi = overcast_zenithbr * 7.0 * PI / 9.0;
    double diffuse_irradiance = 0;
    int l;
    for (l = 0; l < NSSAMP; ++l) {
      diffuse_irradiance += indirect_irradiance_clear->arr.d[l] * 20;  /* 20nm interval */
    }
    free(indirect_irradiance_clear);
    diffuse_irradiance = wmean2(diffuse_irradiance, overcast_ghi, cloud_cover);
    if (diffuse_irradiance > 0) {
        dif_ratio = difhor / WHTEFFICACY / diffuse_irradiance / 1.15;       /* fudge */
    }
  }
  int i, j, k;
  for (j = 0; j < yres; ++j) {
    for (i = 0; i < xres; ++i) {
      SCOLOR radiance = {0};
      SCOLR sky_sclr = {0};

      float px = i / (xres - 1.0);
      float py = j / (yres - 1.0);
      float lambda = ((1 - py) * PI) - (PI / 2.0);
      float phi = (px * 2.0 * PI) - PI;

      FVECT rdir = {cos(lambda) * cos(phi), cos(lambda) * sin(phi),
                    sin(lambda)};

      const double mu = fdot(view_point, rdir) / radius;
      const double nu = fdot(rdir, sundir);

      /* hit ground */
      if (rdir[2] < 0) {
        get_ground_radiance(tau_clear, scat_clear, scat1m_clear, irrad_clear,
                            view_point, rdir, radius, mu, sun_ct, nu, grefl,
                            sundir, radiance);
      } else {
        get_sky_radiance(scat_clear, scat1m_clear, radius, mu, sun_ct, nu,
                         radiance);
      }

      for (k = 0; k < NSSAMP; ++k) {
        radiance[k] *= WVLSPAN;
      }

      if (cloud_cover > 0) {
        double skybr = get_overcast_brightness(rdir[2], overcast_zenithbr);
        if (rdir[2] < 0) {
          for (k = 0; k < NSSAMP; ++k) {
            radiance[k] = wmean2(radiance[k], overcast_grndbr * D6415[k], cloud_cover);
          }
        } else {
          for (k = 0; k < NSSAMP; ++k) {
            radiance[k] = wmean2(radiance[k], skybr * D6415[k], cloud_cover);
          }
        }
      }

      for (k = 0; k < NSSAMP; ++k) {
        radiance[k] *= dif_ratio;
      }

      scolor2scolr(sky_sclr, radiance, NSSAMP);
      putbinary(sky_sclr, LSCOLR, 1, skyfp);
    }
  }
  fclose(skyfp);

  /* Get solar radiance */
  double sun_radiance[NSSAMP] = {0};
  get_solar_radiance(tau_clear, scat_clear, scat1m_clear, sundir, radius,
                     sun_ct, sun_radiance);
  if (cloud_cover > 0) {
    double skybr = get_overcast_brightness(sundir[2], overcast_zenithbr);
    int i;
    for (i = 0; i < NSSAMP; ++i) {
      sun_radiance[i] =
          wmean2(sun_radiance[i], D6415[i] * skybr / WVLSPAN, cloud_cover);
    }
  }

  /* Normalize */
  double sum = 0.0;
  for (i = 0; i < NSSAMP; ++i) {
    sum += sun_radiance[i];
  }
  double mean = sum / NSSAMP;
  for (i = 0; i < NSSAMP; ++i) {
    sun_radiance[i] /= mean;
  }
  double intensity = mean * WVLSPAN;
  if (dirnorm > 0) {
    intensity = dirnorm / SOLOMG / WHTEFFICACY;
  }

  write_rad(sun_radiance, intensity, sundir, ddir, skyfile);
  return 1;
}

static DpPaths get_dppaths(const char *dir, const double aod, const char *mname,
                           const char *tag) {
  DpPaths paths;

  snprintf(paths.tau, PATH_MAX, "%s%ctau_%s_%s_%.2f.dat", dir, DIRSEP, tag,
           mname, aod);
  snprintf(paths.scat, PATH_MAX, "%s%cscat_%s_%s_%.2f.dat", dir, DIRSEP, tag,
           mname, aod);
  snprintf(paths.scat1m, PATH_MAX, "%s%cscat1m_%s_%s_%.2f.dat", dir, DIRSEP,
           tag, mname, aod);
  snprintf(paths.irrad, PATH_MAX, "%s%cirrad_%s_%s_%.2f.dat", dir, DIRSEP, tag,
           mname, aod);

  return paths;
}

static void set_rayleigh_density_profile(Atmosphere *atmos, char *tag,
                                         const int is_summer,
                                         const double s_latitude) {
  if (fabs(s_latitude * 180.0 / PI) > ARCTIC_LAT) {
    tag[0] = 's';
    if (is_summer) {
      tag[1] = 's';
      atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_SS;
      atmos->beta_r0 = BR0_SS;
    } else {
      tag[1] = 'w';
      atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_SW;
      atmos->beta_r0 = BR0_SW;
    }
  } else if (fabs(s_latitude * 180.0 / PI) > TROPIC_LAT) {
    tag[0] = 'm';
    if (is_summer) {
      tag[1] = 's';
      atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_MS;
      atmos->beta_r0 = BR0_MS;
    } else {
      tag[1] = 'w';
      atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_MW;
      atmos->beta_r0 = BR0_MW;
    }
  } else {
    tag[0] = 't';
    tag[1] = 'r';
    atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_T;
    atmos->beta_r0 = BR0_T;
  }
  tag[2] = '\0';
}

static Atmosphere init_atmos(const double aod, const double grefl) {
  Atmosphere atmos = {.ozone_density = {.layers =
                                            {
                                                {.width = 25000.0,
                                                 .exp_term = 0.0,
                                                 .exp_scale = 0.0,
                                                 .linear_term = 1.0 / 15000.0,
                                                 .constant_term = -2.0 / 3.0},
                                                {.width = AH,
                                                 .exp_term = 0.0,
                                                 .exp_scale = 0.0,
                                                 .linear_term = -1.0 / 15000.0,
                                                 .constant_term = 8.0 / 3.0},
                                            }},
                      .rayleigh_density = {.layers =
                                               {
                                                   {.width = AH,
                                                    .exp_term = 1.0,
                                                    .exp_scale = -1.0 / HR_MS,
                                                    .linear_term = 0.0,
                                                    .constant_term = 0.0},
                                               }},
                      .beta_r0 = BR0_MS,
                      .beta_scale = aod / AOD0_CA,
                      .beta_m = NULL,
                      .grefl = grefl};
  return atmos;
}

int main(int argc, char *argv[]) {
  progname = argv[0];
  int month, day;
  double hour;
  FVECT sundir;
  int num_threads = 1;
  int sorder = 4;
  int year = 0;
  int tsolar = 0;
  int got_meridian = 0;
  double grefl = 0.2;
  double ccover = 0.0;
  int res = 64;
  double aod = AOD0_CA;
  char *outname = "out";
  char *mie_path = getpath("mie_ca.dat", getrlibpath(), R_OK);
  char mie_name[20] = "mie_ca";
  char lstag[3];
  char *ddir = ".";
  int i;
  double dirnorm = 0; /* direct normal illuminance */
  double difhor = 0;  /* diffuse horizontal illuminance */

  if (argc == 2 && !strcmp(argv[1], "-defaults")) {
    printf("-i %d\t\t\t\t#scattering order\n", sorder);
    printf("-g %f\t\t\t#ground reflectance\n", grefl);
    printf("-c %f\t\t\t#cloud cover\n", ccover);
    printf("-r %d\t\t\t\t#image resolution\n", res);
    printf("-d %f\t\t\t#broadband aerosol optical depth\n", AOD0_CA);
    printf("-f %s\t\t\t\t#output name (-f)\n", outname);
    printf("-p %s\t\t\t\t#atmos data directory\n", ddir);
    exit(0);
  }

  if (argc < 4) {
    fprintf(stderr,
            "Usage: %s month day hour -y year -a lat -o lon -m tz -d aod -r "
            "res -n nproc -c ccover -l mie -L dirnorm_illum difhor_illum "
            "-g grefl -f outpath\n",
            argv[0]);
    return 0;
  }

  month = atoi(argv[1]);
  if (month < 1 || month > 12) {
    fprintf(stderr, "bad month");
    exit(1);
  }
  day = atoi(argv[2]);
  if (day < 1 || day > 31) {
    fprintf(stderr, "bad month");
    exit(1);
  }
  got_meridian = cvthour(argv[3], &tsolar, &hour);

  if (!compute_sundir(year, month, day, hour, tsolar, sundir)) {
    fprintf(stderr, "Cannot compute solar angle\n");
    exit(1);
  }

  for (i = 4; i < argc; i++) {
    if (argv[i][0] == '-') {
      switch (argv[i][1]) {
      case 'a':
        s_latitude = atof(argv[++i]) * (PI / 180.0);
        break;
      case 'c':
        ccover = atof(argv[++i]);
        break;
      case 'd':
        aod = atof(argv[++i]);
        break;
      case 'f':
        outname = argv[++i];
        break;
      case 'g':
        grefl = atof(argv[++i]);
        break;
      case 'i':
        sorder = atoi(argv[++i]);
        break;
      case 'l':
        mie_path = argv[++i];
        basename(mie_path, mie_name, sizeof(mie_name));
        break;
      case 'm':
        if (got_meridian) {
          ++i;
          break;
        }
        s_meridian = atof(argv[++i]) * (PI / 180.0);
        break;
      case 'n':
        num_threads = atoi(argv[++i]);
        break;
      case 'o':
        s_longitude = atof(argv[++i]) * (PI / 180.0);
        break;
      case 'L':
        dirnorm = atof(argv[++i]);
        difhor = atof(argv[++i]);
        break;
      case 'p':
        ddir = argv[++i];
        break;
      case 'r':
        res = atoi(argv[++i]);
        break;
      case 'y':
        year = atoi(argv[++i]);
        break;
      default:
        fprintf(stderr, "Unknown option %s\n", argv[i]);
        exit(1);
      }
    }
  }
  if (year && (year < 1950) | (year > 2050))
    fprintf(stderr, "%s: warning - year should be in range 1950-2050\n",
            progname);
  if (month && !tsolar && fabs(s_meridian - s_longitude) > 45 * PI / 180)
    fprintf(stderr,
            "%s: warning - %.1f hours btwn. standard meridian and longitude\n",
            progname, (s_longitude - s_meridian) * 12 / PI);

  Atmosphere clear_atmos = init_atmos(aod, grefl);

  int is_summer = (month >= SUMMER_START && month <= SUMMER_END);
  if (s_latitude < 0) {
    is_summer = !is_summer;
  }
  set_rayleigh_density_profile(&clear_atmos, lstag, is_summer, s_latitude);

  /* Load mie density data */
  DATARRAY *mie_dp = getdata(mie_path);
  if (mie_dp == NULL) {
    fprintf(stderr, "Error reading mie data\n");
    return 0;
  }
  clear_atmos.beta_m = mie_dp;

  char gsdir[PATH_MAX];
  size_t siz = strlen(ddir);
  if (ISDIRSEP(ddir[siz - 1]))
    ddir[siz - 1] = '\0';
  snprintf(gsdir, PATH_MAX, "%s%catmos_data", ddir, DIRSEP);
  if (!make_directory(gsdir)) {
    fprintf(stderr, "Failed creating atmos_data directory");
    exit(1);
  }
  DpPaths clear_paths = get_dppaths(gsdir, aod, mie_name, lstag);

  if (getpath(clear_paths.tau, ".", R_OK) == NULL ||
      getpath(clear_paths.scat, ".", R_OK) == NULL ||
      getpath(clear_paths.scat1m, ".", R_OK) == NULL ||
      getpath(clear_paths.irrad, ".", R_OK) == NULL) {
    printf("# Pre-computing...\n");
    if (!precompute(sorder, clear_paths, &clear_atmos, num_threads)) {
      fprintf(stderr, "Pre-compute failed\n");
      return 0;
    }
  }

  DATARRAY *tau_clear_dp = getdata(clear_paths.tau);
  DATARRAY *irrad_clear_dp = getdata(clear_paths.irrad);
  DATARRAY *scat_clear_dp = getdata(clear_paths.scat);
  DATARRAY *scat1m_clear_dp = getdata(clear_paths.scat1m);

  write_header(argc, argv, ccover, grefl, res);

  if (!gen_spect_sky(tau_clear_dp, scat_clear_dp, scat1m_clear_dp,
                     irrad_clear_dp, ccover, sundir, grefl, res, outname, ddir,
                     dirnorm, difhor)) {
    fprintf(stderr, "gen_spect_sky failed\n");
    exit(1);
  }

  freedata(mie_dp);
  freedata(tau_clear_dp);
  freedata(scat_clear_dp);
  freedata(irrad_clear_dp);
  freedata(scat1m_clear_dp);

  return 1;
}
Revision:	2.7
Committed:	Thu Apr 10 23:30:58 2025 UTC (3 weeks ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	HEAD
Changes since 2.6:	+4 -2 lines
Log Message:	feat(gensdaymtx,genssky): TW fixed bug in genssky and added absolute calibration
#	User	Rev	Content
1	greg	2.6	#include "color.h"
2	greg	2.2	#ifndef lint
3	greg	2.6	static const char RCSid[] =
4	greg	2.7	"$Id: genssky.c,v 2.6 2024/10/09 17:22:42 greg Exp $";
5	greg	2.2	#endif
6			/* Main function for generating spectral sky */
7			/* Cloudy sky computed as weight average of clear and cie overcast sky */
8	greg	2.1
9	greg	2.2	#include "atmos.h"
10	greg	2.1	#include "copyright.h"
11			#include "resolu.h"
12	greg	2.2	#include "rtio.h"
13			#include <ctype.h>
14			#ifdef _WIN32
15			#include <windows.h>
16			#else
17			#include <errno.h>
18			#include <sys/stat.h>
19			#include <sys/types.h>
20			#endif
21	greg	2.1
22			char *progname;
23
24			const double ARCTIC_LAT = 67.;
25			const double TROPIC_LAT = 23.;
26			const int SUMMER_START = 4;
27			const int SUMMER_END = 9;
28			const double GNORM = 0.777778;
29
30			const double D65EFF = 203.; /* standard illuminant D65 */
31
32	greg	2.2	/* Mean normalized relative daylight spectra where CCT = 6415K for overcast; */
33	greg	2.1	const double D6415[NSSAMP] = {0.63231, 1.06171, 1.00779, 1.36423, 1.34133,
34			1.27258, 1.26276, 1.26352, 1.22201, 1.13246,
35			1.0434, 1.05547, 0.98212, 0.94445, 0.9722,
36			0.82387, 0.87853, 0.82559, 0.75111, 0.78925};
37
38	greg	2.2	/* European and North American zones */
39			struct {
40			char zname[8]; /* time zone name (all caps) */
41			float zmer; /* standard meridian */
42			} tzone[] = {{"YST", 135}, {"YDT", 120}, {"PST", 120}, {"PDT", 105},
43			{"MST", 105}, {"MDT", 90}, {"CST", 90}, {"CDT", 75},
44			{"EST", 75}, {"EDT", 60}, {"AST", 60}, {"ADT", 45},
45			{"NST", 52.5}, {"NDT", 37.5}, {"GMT", 0}, {"BST", -15},
46			{"CET", -15}, {"CEST", -30}, {"EET", -30}, {"EEST", -45},
47			{"AST", -45}, {"ADT", -60}, {"GST", -60}, {"GDT", -75},
48			{"IST", -82.5}, {"IDT", -97.5}, {"JST", -135}, {"NDT", -150},
49			{"NZST", -180}, {"NZDT", -195}, {"", 0}};
50
51			static int make_directory(const char *path) {
52			#ifdef _WIN32
53			if (CreateDirectory(path, NULL) \|\| GetLastError() == ERROR_ALREADY_EXISTS) {
54			return 1;
55			}
56			return 0;
57			#else
58			if (mkdir(path, 0777) == 0 \|\| errno == EEXIST) {
59			return 1;
60			}
61			return 0;
62			#endif
63			}
64
65	greg	2.3	inline static float deg2rad(float deg) { return deg * (PI / 180.); }
66
67	greg	2.2	static int cvthour(char hs, int tsolar, double *hour) {
68			char *cp = hs;
69			int i, j;
70
71			if ((tsolar = cp == '+'))
72			cp++; /* solar time? */
73			while (isdigit(*cp))
74			cp++;
75			if (*cp == ':')
76			*hour = atoi(hs) + atoi(++cp) / 60.0;
77			else {
78			*hour = atof(hs);
79			if (*cp == '.')
80			cp++;
81			}
82			while (isdigit(*cp))
83			cp++;
84			if (!*cp)
85			return (0);
86			if (tsolar \|\| !isalpha(cp)) {
87			fprintf(stderr, "%s: bad time format: %s\n", progname, hs);
88			exit(1);
89			}
90			i = 0;
91			do {
92			for (j = 0; cp[j]; j++)
93			if (toupper(cp[j]) != tzone[i].zname[j])
94			break;
95			if (!cp[j] && !tzone[i].zname[j]) {
96			s_meridian = tzone[i].zmer * (PI / 180);
97			return (1);
98			}
99			} while (tzone[i++].zname[0]);
100
101			fprintf(stderr, "%s: unknown time zone: %s\n", progname, cp);
102			fprintf(stderr, "Known time zones:\n\t%s", tzone[0].zname);
103			for (i = 1; tzone[i].zname[0]; i++)
104			fprintf(stderr, " %s", tzone[i].zname);
105			putc('\n', stderr);
106			exit(1);
107			}
108
109			static void basename(const char path, char output, size_t outsize) {
110			const char *last_slash = strrchr(path, '/');
111			const char *last_backslash = strrchr(path, '\\');
112			const char *filename = path;
113			const char *last_dot;
114
115			if (last_slash && last_backslash) {
116			filename =
117			(last_slash > last_backslash) ? last_slash + 1 : last_backslash + 1;
118			} else if (last_slash) {
119			filename = last_slash + 1;
120			} else if (last_backslash) {
121			filename = last_backslash + 1;
122			}
123
124			last_dot = strrchr(filename, '.');
125			if (last_dot) {
126			size_t length = last_dot - filename;
127			if (length < outsize) {
128			strncpy(output, filename, length);
129			output[length] = '\0';
130			} else {
131			strncpy(output, filename, outsize - 1);
132			output[outsize - 1] = '\0';
133			}
134			}
135			}
136
137	greg	2.3	static char join_paths(const char path1, const char *path2) {
138	greg	2.2	size_t len1 = strlen(path1);
139			size_t len2 = strlen(path2);
140			int need_separator = (path1[len1 - 1] != DIRSEP);
141
142			char *result = malloc(len1 + len2 + (need_separator ? 2 : 1));
143			if (!result)
144			return NULL;
145
146			strcpy(result, path1);
147			if (need_separator) {
148			result[len1] = DIRSEP;
149			len1++;
150			}
151			strcpy(result + len1, path2);
152
153			return result;
154			}
155
156	greg	2.1	static inline double wmean2(const double a, const double b, const double x) {
157			return a * (1 - x) + b * x;
158			}
159
160			static inline double wmean(const double a, const double x, const double b,
161			const double y) {
162			return (a * x + b * y) / (a + b);
163			}
164
165	greg	2.6	static double get_overcast_zenith_brightness(const double sundir[3]) {
166	greg	2.1	double zenithbr;
167			if (sundir[2] < 0) {
168			zenithbr = 0;
169			} else {
170			zenithbr = (8.6 * sundir[2] + .123) * 1000.0 / D65EFF;
171			}
172			return zenithbr;
173			}
174
175	greg	2.2	/* from gensky.c */
176	greg	2.1	static double get_overcast_brightness(const double dz, const double zenithbr) {
177			double groundbr = zenithbr * GNORM;
178			return wmean(pow(dz + 1.01, 10), zenithbr * (1 + 2 * dz) / 3,
179			pow(dz + 1.01, -10), groundbr);
180			}
181
182	greg	2.2	static void write_header(const int argc, char **argv, const double cloud_cover,
183			const double grefl, const int res) {
184	greg	2.4	int i;
185	greg	2.2	printf("# ");
186	greg	2.4	for (i = 0; i < argc; i++) {
187	greg	2.2	printf("%s ", argv[i]);
188			}
189			printf("\n");
190	greg	2.3	printf(
191			"#Cloud cover: %g\n#Ground reflectance: %g\n#Sky map resolution: %d\n\n",
192			cloud_cover, grefl, res);
193	greg	2.2	}
194
195	greg	2.6	static void write_rad(const double *sun_radiance, const double intensity,
196			const FVECT sundir, const char *ddir,
197			const char *skyfile) {
198	greg	2.1	if (sundir[2] > 0) {
199	greg	2.2	printf("void spectrum sunrad\n0\n0\n22 380 780 ");
200	greg	2.4	int i;
201			for (i = 0; i < NSSAMP; ++i) {
202	greg	2.6	printf("%.3f ", sun_radiance[i]);
203	greg	2.1	}
204	greg	2.2	printf("\n\nsunrad light solar\n0\n0\n3 %.1f %.1f %.1f\n\n", intensity,
205			intensity, intensity);
206			printf("solar source sun\n0\n0\n4 %f %f %f 0.533\n\n", sundir[0], sundir[1],
207			sundir[2]);
208			}
209	greg	2.5	printf("void specpict skyfunc\n5 noop %s . 'Atan2(Dy,Dx)/PI+1' "
210			"'1-Acos(Dz)/PI'\n0\n0\n\n",
211	greg	2.2	skyfile);
212	greg	2.1	}
213
214			static void write_hsr_header(FILE fp, RESOLU res) {
215	greg	2.3	float wvsplit[4] = {380, 480, 588, 780};
216	greg	2.1	newheader("RADIANCE", fp);
217			fputncomp(NSSAMP, fp);
218			fputwlsplit(wvsplit, fp);
219			fputformat(SPECFMT, fp);
220			fputc('\n', fp);
221			fputsresolu(res, fp);
222			}
223
224	greg	2.3	static inline float frac(float x) { return x - floor(x); }
225
226	greg	2.1	int gen_spect_sky(DATARRAY tau_clear, DATARRAY scat_clear,
227			DATARRAY scat1m_clear, DATARRAY irrad_clear,
228			const double cloud_cover, const FVECT sundir,
229	greg	2.3	const double grefl, const int res, const char *outname,
230	greg	2.6	const char *ddir, const double dirnorm, const double difhor) {
231	greg	2.1	char skyfile[PATH_MAX];
232	greg	2.3	if (!snprintf(skyfile, sizeof(skyfile), "%s%c%s_sky.hsr", ddir, DIRSEP,
233			outname)) {
234	greg	2.1	fprintf(stderr, "Error setting sky file name\n");
235			return 0;
236			};
237	greg	2.3	int xres = res;
238			int yres = xres / 2;
239			RESOLU rs = {PIXSTANDARD, xres, yres};
240	greg	2.1	FILE *skyfp = fopen(skyfile, "w");
241			write_hsr_header(skyfp, &rs);
242
243			CNDX[3] = NSSAMP;
244
245	greg	2.3	FVECT view_point = {0, 0, ER + 10};
246	greg	2.1	const double radius = VLEN(view_point);
247			const double sun_ct = fdot(view_point, sundir) / radius;
248	greg	2.6
249			double overcast_zenithbr = get_overcast_zenith_brightness(sundir);
250			double overcast_grndbr = overcast_zenithbr * GNORM;
251
252			double dif_ratio = 1;
253			if (difhor > 0) {
254			DATARRAY *indirect_irradiance_clear = get_indirect_irradiance(irrad_clear, radius, sun_ct);
255			double overcast_ghi = overcast_zenithbr * 7.0 * PI / 9.0;
256			double diffuse_irradiance = 0;
257			int l;
258			for (l = 0; l < NSSAMP; ++l) {
259			diffuse_irradiance += indirect_irradiance_clear->arr.d[l] * 20; /* 20nm interval */
260			}
261			free(indirect_irradiance_clear);
262			diffuse_irradiance = wmean2(diffuse_irradiance, overcast_ghi, cloud_cover);
263	greg	2.7	if (diffuse_irradiance > 0) {
264			dif_ratio = difhor / WHTEFFICACY / diffuse_irradiance / 1.15; /* fudge */
265			}
266	greg	2.6	}
267	greg	2.4	int i, j, k;
268			for (j = 0; j < yres; ++j) {
269			for (i = 0; i < xres; ++i) {
270	greg	2.3	SCOLOR radiance = {0};
271	greg	2.1	SCOLR sky_sclr = {0};
272
273	greg	2.3	float px = i / (xres - 1.0);
274			float py = j / (yres - 1.0);
275			float lambda = ((1 - py) * PI) - (PI / 2.0);
276			float phi = (px * 2.0 * PI) - PI;
277
278			FVECT rdir = {cos(lambda) * cos(phi), cos(lambda) * sin(phi),
279			sin(lambda)};
280
281			const double mu = fdot(view_point, rdir) / radius;
282			const double nu = fdot(rdir, sundir);
283
284			/* hit ground */
285			if (rdir[2] < 0) {
286			get_ground_radiance(tau_clear, scat_clear, scat1m_clear, irrad_clear,
287			view_point, rdir, radius, mu, sun_ct, nu, grefl,
288			sundir, radiance);
289			} else {
290			get_sky_radiance(scat_clear, scat1m_clear, radius, mu, sun_ct, nu,
291			radiance);
292			}
293	greg	2.1
294	greg	2.4	for (k = 0; k < NSSAMP; ++k) {
295	greg	2.3	radiance[k] *= WVLSPAN;
296	greg	2.1	}
297
298			if (cloud_cover > 0) {
299	greg	2.6	double skybr = get_overcast_brightness(rdir[2], overcast_zenithbr);
300	greg	2.3	if (rdir[2] < 0) {
301	greg	2.4	for (k = 0; k < NSSAMP; ++k) {
302	greg	2.6	radiance[k] = wmean2(radiance[k], overcast_grndbr * D6415[k], cloud_cover);
303	greg	2.3	}
304			} else {
305	greg	2.4	for (k = 0; k < NSSAMP; ++k) {
306	greg	2.3	radiance[k] = wmean2(radiance[k], skybr * D6415[k], cloud_cover);
307			}
308	greg	2.1	}
309			}
310
311	greg	2.6	for (k = 0; k < NSSAMP; ++k) {
312			radiance[k] *= dif_ratio;
313			}
314
315			scolor2scolr(sky_sclr, radiance, NSSAMP);
316	greg	2.1	putbinary(sky_sclr, LSCOLR, 1, skyfp);
317			}
318			}
319			fclose(skyfp);
320
321	greg	2.2	/* Get solar radiance */
322	greg	2.1	double sun_radiance[NSSAMP] = {0};
323			get_solar_radiance(tau_clear, scat_clear, scat1m_clear, sundir, radius,
324			sun_ct, sun_radiance);
325			if (cloud_cover > 0) {
326	greg	2.6	double skybr = get_overcast_brightness(sundir[2], overcast_zenithbr);
327	greg	2.4	int i;
328			for (i = 0; i < NSSAMP; ++i) {
329	greg	2.1	sun_radiance[i] =
330			wmean2(sun_radiance[i], D6415[i] * skybr / WVLSPAN, cloud_cover);
331			}
332			}
333
334	greg	2.6	/* Normalize */
335			double sum = 0.0;
336			for (i = 0; i < NSSAMP; ++i) {
337			sum += sun_radiance[i];
338			}
339			double mean = sum / NSSAMP;
340			for (i = 0; i < NSSAMP; ++i) {
341			sun_radiance[i] /= mean;
342			}
343			double intensity = mean * WVLSPAN;
344			if (dirnorm > 0) {
345			intensity = dirnorm / SOLOMG / WHTEFFICACY;
346			}
347
348			write_rad(sun_radiance, intensity, sundir, ddir, skyfile);
349	greg	2.1	return 1;
350			}
351
352	greg	2.2	static DpPaths get_dppaths(const char dir, const double aod, const char mname,
353			const char *tag) {
354	greg	2.1	DpPaths paths;
355
356	greg	2.2	snprintf(paths.tau, PATH_MAX, "%s%ctau_%s_%s_%.2f.dat", dir, DIRSEP, tag,
357			mname, aod);
358			snprintf(paths.scat, PATH_MAX, "%s%cscat_%s_%s_%.2f.dat", dir, DIRSEP, tag,
359			mname, aod);
360			snprintf(paths.scat1m, PATH_MAX, "%s%cscat1m_%s_%s_%.2f.dat", dir, DIRSEP,
361			tag, mname, aod);
362			snprintf(paths.irrad, PATH_MAX, "%s%cirrad_%s_%s_%.2f.dat", dir, DIRSEP, tag,
363			mname, aod);
364	greg	2.1
365			return paths;
366			}
367
368	greg	2.2	static void set_rayleigh_density_profile(Atmosphere atmos, char tag,
369			const int is_summer,
370	greg	2.1	const double s_latitude) {
371	greg	2.2	if (fabs(s_latitude * 180.0 / PI) > ARCTIC_LAT) {
372	greg	2.1	tag[0] = 's';
373			if (is_summer) {
374			tag[1] = 's';
375			atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_SS;
376			atmos->beta_r0 = BR0_SS;
377			} else {
378			tag[1] = 'w';
379			atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_SW;
380			atmos->beta_r0 = BR0_SW;
381			}
382	greg	2.2	} else if (fabs(s_latitude * 180.0 / PI) > TROPIC_LAT) {
383	greg	2.1	tag[0] = 'm';
384			if (is_summer) {
385			tag[1] = 's';
386			atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_MS;
387			atmos->beta_r0 = BR0_MS;
388			} else {
389			tag[1] = 'w';
390			atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_MW;
391			atmos->beta_r0 = BR0_MW;
392			}
393			} else {
394			tag[0] = 't';
395			tag[1] = 'r';
396			atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_T;
397			atmos->beta_r0 = BR0_T;
398			}
399			tag[2] = '\0';
400			}
401
402			static Atmosphere init_atmos(const double aod, const double grefl) {
403	greg	2.2	Atmosphere atmos = {.ozone_density = {.layers =
404			{
405			{.width = 25000.0,
406			.exp_term = 0.0,
407			.exp_scale = 0.0,
408			.linear_term = 1.0 / 15000.0,
409			.constant_term = -2.0 / 3.0},
410			{.width = AH,
411			.exp_term = 0.0,
412			.exp_scale = 0.0,
413			.linear_term = -1.0 / 15000.0,
414			.constant_term = 8.0 / 3.0},
415			}},
416			.rayleigh_density = {.layers =
417			{
418			{.width = AH,
419			.exp_term = 1.0,
420			.exp_scale = -1.0 / HR_MS,
421			.linear_term = 0.0,
422			.constant_term = 0.0},
423			}},
424			.beta_r0 = BR0_MS,
425			.beta_scale = aod / AOD0_CA,
426			.beta_m = NULL,
427			.grefl = grefl};
428	greg	2.1	return atmos;
429			}
430
431			int main(int argc, char *argv[]) {
432			progname = argv[0];
433			int month, day;
434			double hour;
435			FVECT sundir;
436			int num_threads = 1;
437			int sorder = 4;
438			int year = 0;
439			int tsolar = 0;
440	greg	2.2	int got_meridian = 0;
441	greg	2.1	double grefl = 0.2;
442			double ccover = 0.0;
443	greg	2.3	int res = 64;
444	greg	2.1	double aod = AOD0_CA;
445			char *outname = "out";
446			char *mie_path = getpath("mie_ca.dat", getrlibpath(), R_OK);
447	greg	2.2	char mie_name[20] = "mie_ca";
448	greg	2.1	char lstag[3];
449	greg	2.2	char *ddir = ".";
450	greg	2.4	int i;
451	greg	2.6	double dirnorm = 0; /* direct normal illuminance */
452			double difhor = 0; /* diffuse horizontal illuminance */
453	greg	2.2
454	greg	2.3	if (argc == 2 && !strcmp(argv[1], "-defaults")) {
455	greg	2.2	printf("-i %d\t\t\t\t#scattering order\n", sorder);
456			printf("-g %f\t\t\t#ground reflectance\n", grefl);
457			printf("-c %f\t\t\t#cloud cover\n", ccover);
458			printf("-r %d\t\t\t\t#image resolution\n", res);
459			printf("-d %f\t\t\t#broadband aerosol optical depth\n", AOD0_CA);
460			printf("-f %s\t\t\t\t#output name (-f)\n", outname);
461			printf("-p %s\t\t\t\t#atmos data directory\n", ddir);
462	greg	2.3	exit(0);
463	greg	2.2	}
464	greg	2.1
465			if (argc < 4) {
466	greg	2.2	fprintf(stderr,
467			"Usage: %s month day hour -y year -a lat -o lon -m tz -d aod -r "
468	greg	2.6	"res -n nproc -c ccover -l mie -L dirnorm_illum difhor_illum "
469			"-g grefl -f outpath\n",
470	greg	2.1	argv[0]);
471			return 0;
472			}
473
474			month = atoi(argv[1]);
475	greg	2.2	if (month < 1 \|\| month > 12) {
476			fprintf(stderr, "bad month");
477			exit(1);
478			}
479	greg	2.1	day = atoi(argv[2]);
480	greg	2.2	if (day < 1 \|\| day > 31) {
481			fprintf(stderr, "bad month");
482			exit(1);
483			}
484			got_meridian = cvthour(argv[3], &tsolar, &hour);
485	greg	2.1
486			if (!compute_sundir(year, month, day, hour, tsolar, sundir)) {
487			fprintf(stderr, "Cannot compute solar angle\n");
488			exit(1);
489			}
490
491	greg	2.4	for (i = 4; i < argc; i++) {
492	greg	2.1	if (argv[i][0] == '-') {
493			switch (argv[i][1]) {
494			case 'a':
495			s_latitude = atof(argv[++i]) * (PI / 180.0);
496			break;
497			case 'c':
498			ccover = atof(argv[++i]);
499			break;
500			case 'd':
501			aod = atof(argv[++i]);
502			break;
503	greg	2.2	case 'f':
504			outname = argv[++i];
505			break;
506			case 'g':
507			grefl = atof(argv[++i]);
508			break;
509	greg	2.1	case 'i':
510			sorder = atoi(argv[++i]);
511			break;
512			case 'l':
513			mie_path = argv[++i];
514	greg	2.2	basename(mie_path, mie_name, sizeof(mie_name));
515	greg	2.1	break;
516			case 'm':
517	greg	2.2	if (got_meridian) {
518			++i;
519			break;
520			}
521	greg	2.1	s_meridian = atof(argv[++i]) * (PI / 180.0);
522			break;
523			case 'n':
524			num_threads = atoi(argv[++i]);
525			break;
526	greg	2.2	case 'o':
527			s_longitude = atof(argv[++i]) * (PI / 180.0);
528	greg	2.1	break;
529	greg	2.6	case 'L':
530			dirnorm = atof(argv[++i]);
531			difhor = atof(argv[++i]);
532			break;
533	greg	2.2	case 'p':
534			ddir = argv[++i];
535	greg	2.1	break;
536			case 'r':
537			res = atoi(argv[++i]);
538			break;
539	greg	2.2	case 'y':
540			year = atoi(argv[++i]);
541			break;
542	greg	2.1	default:
543			fprintf(stderr, "Unknown option %s\n", argv[i]);
544			exit(1);
545			}
546			}
547			}
548	greg	2.2	if (year && (year < 1950) \| (year > 2050))
549			fprintf(stderr, "%s: warning - year should be in range 1950-2050\n",
550			progname);
551			if (month && !tsolar && fabs(s_meridian - s_longitude) > 45 * PI / 180)
552			fprintf(stderr,
553			"%s: warning - %.1f hours btwn. standard meridian and longitude\n",
554			progname, (s_longitude - s_meridian) * 12 / PI);
555	greg	2.1
556			Atmosphere clear_atmos = init_atmos(aod, grefl);
557
558			int is_summer = (month >= SUMMER_START && month <= SUMMER_END);
559			if (s_latitude < 0) {
560			is_summer = !is_summer;
561			}
562			set_rayleigh_density_profile(&clear_atmos, lstag, is_summer, s_latitude);
563
564	greg	2.2	/* Load mie density data */
565	greg	2.1	DATARRAY *mie_dp = getdata(mie_path);
566			if (mie_dp == NULL) {
567			fprintf(stderr, "Error reading mie data\n");
568			return 0;
569			}
570			clear_atmos.beta_m = mie_dp;
571
572	greg	2.2	char gsdir[PATH_MAX];
573			size_t siz = strlen(ddir);
574	greg	2.3	if (ISDIRSEP(ddir[siz - 1]))
575			ddir[siz - 1] = '\0';
576	greg	2.2	snprintf(gsdir, PATH_MAX, "%s%catmos_data", ddir, DIRSEP);
577			if (!make_directory(gsdir)) {
578			fprintf(stderr, "Failed creating atmos_data directory");
579			exit(1);
580			}
581			DpPaths clear_paths = get_dppaths(gsdir, aod, mie_name, lstag);
582	greg	2.1
583			if (getpath(clear_paths.tau, ".", R_OK) == NULL \|\|
584			getpath(clear_paths.scat, ".", R_OK) == NULL \|\|
585			getpath(clear_paths.scat1m, ".", R_OK) == NULL \|\|
586			getpath(clear_paths.irrad, ".", R_OK) == NULL) {
587	greg	2.2	printf("# Pre-computing...\n");
588	greg	2.1	if (!precompute(sorder, clear_paths, &clear_atmos, num_threads)) {
589	greg	2.2	fprintf(stderr, "Pre-compute failed\n");
590	greg	2.1	return 0;
591			}
592			}
593
594			DATARRAY *tau_clear_dp = getdata(clear_paths.tau);
595			DATARRAY *irrad_clear_dp = getdata(clear_paths.irrad);
596			DATARRAY *scat_clear_dp = getdata(clear_paths.scat);
597			DATARRAY *scat1m_clear_dp = getdata(clear_paths.scat1m);
598
599	greg	2.2	write_header(argc, argv, ccover, grefl, res);
600
601	greg	2.1	if (!gen_spect_sky(tau_clear_dp, scat_clear_dp, scat1m_clear_dp,
602	greg	2.6	irrad_clear_dp, ccover, sundir, grefl, res, outname, ddir,
603			dirnorm, difhor)) {
604	greg	2.1	fprintf(stderr, "gen_spect_sky failed\n");
605			exit(1);
606			}
607
608			freedata(mie_dp);
609			freedata(tau_clear_dp);
610			freedata(scat_clear_dp);
611			freedata(irrad_clear_dp);
612			freedata(scat1m_clear_dp);
613
614			return 1;
615			}