| 1 |
// Main function for generating spectral sky
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| 2 |
// Cloudy sky computed as weight average of clear and cie overcast sky
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| 3 |
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| 4 |
#include "copyright.h"
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| 5 |
#include "atmos.h"
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| 6 |
#include "resolu.h"
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| 7 |
#include "view.h"
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| 8 |
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| 9 |
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| 10 |
char *progname;
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| 11 |
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| 12 |
const double ARCTIC_LAT = 67.;
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| 13 |
const double TROPIC_LAT = 23.;
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| 14 |
const int SUMMER_START = 4;
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| 15 |
const int SUMMER_END = 9;
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| 16 |
const double GNORM = 0.777778;
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| 17 |
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| 18 |
const double D65EFF = 203.; /* standard illuminant D65 */
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| 19 |
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| 20 |
// Mean normalized relative daylight spectra where CCT = 6415K for overcast;
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| 21 |
const double D6415[NSSAMP] = {0.63231, 1.06171, 1.00779, 1.36423, 1.34133,
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| 22 |
1.27258, 1.26276, 1.26352, 1.22201, 1.13246,
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| 23 |
1.0434, 1.05547, 0.98212, 0.94445, 0.9722,
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| 24 |
0.82387, 0.87853, 0.82559, 0.75111, 0.78925};
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| 25 |
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| 26 |
static inline double wmean2(const double a, const double b, const double x) {
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| 27 |
return a * (1 - x) + b * x;
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| 28 |
}
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| 29 |
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| 30 |
static inline double wmean(const double a, const double x, const double b,
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| 31 |
const double y) {
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| 32 |
return (a * x + b * y) / (a + b);
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}
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| 35 |
static double get_zenith_brightness(const double sundir[3]) {
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double zenithbr;
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| 37 |
if (sundir[2] < 0) {
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| 38 |
zenithbr = 0;
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| 39 |
} else {
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zenithbr = (8.6 * sundir[2] + .123) * 1000.0 / D65EFF;
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}
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return zenithbr;
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| 43 |
}
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| 45 |
// from gensky.c
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| 46 |
static double get_overcast_brightness(const double dz, const double zenithbr) {
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double groundbr = zenithbr * GNORM;
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return wmean(pow(dz + 1.01, 10), zenithbr * (1 + 2 * dz) / 3,
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| 49 |
pow(dz + 1.01, -10), groundbr);
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}
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| 52 |
static void write_rad_file(FILE *fp, const double *sun_radiance,
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| 53 |
const FVECT sundir, const char skyfile[PATH_MAX],
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| 54 |
const char grndfile[PATH_MAX]) {
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| 55 |
if (sundir[2] > 0) {
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| 56 |
fprintf(fp, "void spectrum sunrad\n0\n0\n22 380 780 ");
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| 57 |
for (int i = 0; i < NSSAMP; ++i) {
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fprintf(fp, "%.1f ", sun_radiance[i] * WVLSPAN);
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}
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fprintf(fp, "\n\nsunrad light solar\n0\n0\n3 1 1 1\n\n");
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fprintf(fp, "solar source sun\n0\n0\n4 %f %f %f 0.533\n\n", sundir[0],
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sundir[1], sundir[2]);
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}
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fprintf(fp,
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"void specpict skyfunc\n8 noop %s fisheye.cal fish_u fish_v -rx 90 "
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"-mx\n0\n0\n\n",
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skyfile);
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fprintf(fp, "skyfunc glow sky_glow\n0\n0\n4 1 1 1 0\n\n");
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fprintf(fp, "sky_glow source sky\n0\n0\n4 0 0 1 180\n\n");
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fprintf(fp,
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"void specpict grndmap\n8 noop %s fisheye.cal fish_u fish_v -rx -90 "
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"-my\n0\n0\n\n",
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grndfile);
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fprintf(fp, "grndmap glow ground_glow\n0\n0\n4 1 1 1 0\n\n");
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fprintf(fp, "ground_glow source ground_source\n0\n0\n4 0 0 -1 180\n\n");
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}
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static void write_hsr_header(FILE *fp, RESOLU *res) {
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float wvsplit[4] = {380, 480, 588,
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780}; // RGB wavelength limits+partitions (nm)
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newheader("RADIANCE", fp);
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fputncomp(NSSAMP, fp);
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fputwlsplit(wvsplit, fp);
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fputformat(SPECFMT, fp);
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fputc('\n', fp);
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fputsresolu(res, fp);
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}
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int gen_spect_sky(DATARRAY *tau_clear, DATARRAY *scat_clear,
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DATARRAY *scat1m_clear, DATARRAY *irrad_clear,
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const double cloud_cover, const FVECT sundir,
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const double grefl, const int res, const char *outname) {
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char radfile[PATH_MAX];
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char skyfile[PATH_MAX];
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char grndfile[PATH_MAX];
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if (!snprintf(radfile, sizeof(radfile), "%s.rad", outname)) {
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fprintf(stderr, "Error setting rad file name\n");
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return 0;
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};
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if (!snprintf(skyfile, sizeof(skyfile), "%s_sky.hsr", outname)) {
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fprintf(stderr, "Error setting sky file name\n");
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return 0;
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};
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if (!snprintf(grndfile, sizeof(grndfile), "%s_ground.hsr", outname)) {
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fprintf(stderr, "Error setting ground file name\n");
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return 0;
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}
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RESOLU rs = {PIXSTANDARD, res, res};
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FILE *skyfp = fopen(skyfile, "w");
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FILE *grndfp = fopen(grndfile, "w");
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write_hsr_header(grndfp, &rs);
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write_hsr_header(skyfp, &rs);
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VIEW skyview = {VT_ANG, {0., 0., 0.}, {0., 0., 1.}, {0., 1., 0.}, 1.,
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180., 180., 0., 0., 0.,
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0., {0., 0., 0.}, {0., 0., 0.}, 0., 0.};
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VIEW grndview = {
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VT_ANG, {0., 0., 0.}, {0., 0., -1.}, {0., 1., 0.}, 1., 180., 180., 0., 0.,
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0., 0., {0., 0., 0.}, {0., 0., 0.}, 0., 0.};
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setview(&skyview);
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setview(&grndview);
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| 124 |
CNDX[3] = NSSAMP;
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FVECT view_point = {0, 0, ER};
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const double radius = VLEN(view_point);
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const double sun_ct = fdot(view_point, sundir) / radius;
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for (unsigned int j = 0; j < res; ++j) {
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for (unsigned int i = 0; i < res; ++i) {
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| 131 |
RREAL loc[2];
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FVECT rorg = {0};
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FVECT rdir_sky = {0};
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| 134 |
FVECT rdir_grnd = {0};
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SCOLOR sky_radiance = {0};
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SCOLOR ground_radiance = {0};
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SCOLR sky_sclr = {0};
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SCOLR ground_sclr = {0};
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pix2loc(loc, &rs, i, j);
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viewray(rorg, rdir_sky, &skyview, loc[0], loc[1]);
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viewray(rorg, rdir_grnd, &grndview, loc[0], loc[1]);
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| 144 |
const double mu_sky = fdot(view_point, rdir_sky) / radius;
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const double nu_sky = fdot(rdir_sky, sundir);
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| 147 |
const double mu_grnd = fdot(view_point, rdir_grnd) / radius;
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const double nu_grnd = fdot(rdir_grnd, sundir);
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| 149 |
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| 150 |
get_sky_radiance(scat_clear, scat1m_clear, radius, mu_sky, sun_ct, nu_sky,
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| 151 |
sky_radiance);
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get_ground_radiance(tau_clear, scat_clear, scat1m_clear, irrad_clear,
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view_point, rdir_grnd, radius, mu_grnd, sun_ct,
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nu_grnd, grefl, sundir, ground_radiance);
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| 155 |
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| 156 |
for (int k = 0; k < NSSAMP; ++k) {
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| 157 |
sky_radiance[k] *= WVLSPAN;
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| 158 |
ground_radiance[k] *= WVLSPAN;
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}
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| 160 |
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| 161 |
if (cloud_cover > 0) {
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| 162 |
double zenithbr = get_zenith_brightness(sundir);
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| 163 |
double grndbr = zenithbr * GNORM;
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| 164 |
double skybr = get_overcast_brightness(rdir_sky[2], zenithbr);
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| 165 |
for (int k = 0; k < NSSAMP; ++k) {
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sky_radiance[k] =
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wmean2(sky_radiance[k], skybr * D6415[k], cloud_cover);
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ground_radiance[k] =
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wmean2(ground_radiance[k], grndbr * D6415[k], cloud_cover);
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}
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}
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| 173 |
scolor2scolr(sky_sclr, sky_radiance, 20);
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putbinary(sky_sclr, LSCOLR, 1, skyfp);
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scolor2scolr(ground_sclr, ground_radiance, 20);
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putbinary(ground_sclr, LSCOLR, 1, grndfp);
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}
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}
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fclose(skyfp);
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fclose(grndfp);
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| 182 |
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// Get solar radiance
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double sun_radiance[NSSAMP] = {0};
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get_solar_radiance(tau_clear, scat_clear, scat1m_clear, sundir, radius,
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sun_ct, sun_radiance);
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if (cloud_cover > 0) {
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double zenithbr = get_zenith_brightness(sundir);
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| 189 |
double skybr = get_overcast_brightness(sundir[2], zenithbr);
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for (int i = 0; i < NSSAMP; ++i) {
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sun_radiance[i] =
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wmean2(sun_radiance[i], D6415[i] * skybr / WVLSPAN, cloud_cover);
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}
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}
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| 195 |
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| 196 |
FILE *rfp = fopen(radfile, "w");
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write_rad_file(rfp, sun_radiance, sundir, skyfile, grndfile);
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fclose(rfp);
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return 1;
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}
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static DpPaths get_dppaths(const double aod, const char *tag) {
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DpPaths paths;
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| 205 |
snprintf(paths.tau, PATH_MAX, "tau_%s_%.2f.dat", tag, aod);
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snprintf(paths.scat, PATH_MAX, "scat_%s_%.2f.dat", tag, aod);
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snprintf(paths.scat1m, PATH_MAX, "scat1m_%s_%.2f.dat", tag, aod);
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snprintf(paths.irrad, PATH_MAX, "irrad_%s_%.2f.dat", tag, aod);
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return paths;
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}
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static void set_rayleigh_density_profile(Atmosphere *atmos, char *tag, const int is_summer,
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const double s_latitude) {
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// Set rayleigh density profile
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if (fabs(s_latitude*180.0 / PI) > ARCTIC_LAT) {
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tag[0] = 's';
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| 218 |
if (is_summer) {
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tag[1] = 's';
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atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_SS;
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atmos->beta_r0 = BR0_SS;
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} else {
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| 223 |
tag[1] = 'w';
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| 224 |
atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_SW;
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atmos->beta_r0 = BR0_SW;
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| 226 |
}
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| 227 |
} else if (fabs(s_latitude*180.0/PI) > TROPIC_LAT) {
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tag[0] = 'm';
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| 229 |
if (is_summer) {
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| 230 |
tag[1] = 's';
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atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_MS;
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| 232 |
atmos->beta_r0 = BR0_MS;
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| 233 |
} else {
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| 234 |
tag[1] = 'w';
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| 235 |
atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_MW;
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| 236 |
atmos->beta_r0 = BR0_MW;
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| 237 |
}
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| 238 |
} else {
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| 239 |
tag[0] = 't';
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| 240 |
tag[1] = 'r';
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| 241 |
atmos->rayleigh_density.layers[0].exp_scale = -1.0 / HR_T;
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| 242 |
atmos->beta_r0 = BR0_T;
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| 243 |
}
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| 244 |
tag[2] = '\0';
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| 245 |
}
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| 246 |
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| 247 |
static Atmosphere init_atmos(const double aod, const double grefl) {
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| 248 |
Atmosphere atmos = {
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| 249 |
.ozone_density = {.layers =
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| 250 |
{
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| 251 |
{.width = 25000.0,
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| 252 |
.exp_term = 0.0,
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| 253 |
.exp_scale = 0.0,
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| 254 |
.linear_term = 1.0 / 15000.0,
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| 255 |
.constant_term = -2.0 / 3.0},
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| 256 |
{.width = AH,
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| 257 |
.exp_term = 0.0,
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| 258 |
.exp_scale = 0.0,
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| 259 |
.linear_term = -1.0 / 15000.0,
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| 260 |
.constant_term = 8.0 / 3.0},
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| 261 |
}},
|
| 262 |
.rayleigh_density = {.layers =
|
| 263 |
{
|
| 264 |
{.width = AH,
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| 265 |
.exp_term = 1.0,
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| 266 |
.exp_scale = -1.0 / HR_MS,
|
| 267 |
.linear_term = 0.0,
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| 268 |
.constant_term = 0.0},
|
| 269 |
}},
|
| 270 |
.beta_r0 = BR0_MS,
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| 271 |
.beta_scale = aod / AOD0_CA,
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| 272 |
.beta_m = NULL,
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| 273 |
.grefl = grefl
|
| 274 |
};
|
| 275 |
return atmos;
|
| 276 |
}
|
| 277 |
|
| 278 |
int main(int argc, char *argv[]) {
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| 279 |
progname = argv[0];
|
| 280 |
int month, day;
|
| 281 |
double hour;
|
| 282 |
FVECT sundir;
|
| 283 |
int num_threads = 1;
|
| 284 |
int sorder = 4;
|
| 285 |
int year = 0;
|
| 286 |
int tsolar = 0;
|
| 287 |
double grefl = 0.2;
|
| 288 |
double ccover = 0.0;
|
| 289 |
int res = 128;
|
| 290 |
double aod = AOD0_CA;
|
| 291 |
char *outname = "out";
|
| 292 |
char *mie_path = getpath("mie_ca.dat", getrlibpath(), R_OK);
|
| 293 |
char lstag[3];
|
| 294 |
|
| 295 |
if (argc < 4) {
|
| 296 |
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 -g grefl -f outpath\n",
|
| 297 |
argv[0]);
|
| 298 |
return 0;
|
| 299 |
}
|
| 300 |
|
| 301 |
month = atoi(argv[1]);
|
| 302 |
day = atoi(argv[2]);
|
| 303 |
hour = atof(argv[3]);
|
| 304 |
|
| 305 |
if (!compute_sundir(year, month, day, hour, tsolar, sundir)) {
|
| 306 |
fprintf(stderr, "Cannot compute solar angle\n");
|
| 307 |
exit(1);
|
| 308 |
}
|
| 309 |
|
| 310 |
for (int i = 4; i < argc; i++) {
|
| 311 |
if (argv[i][0] == '-') {
|
| 312 |
switch (argv[i][1]) {
|
| 313 |
case 'a':
|
| 314 |
s_latitude = atof(argv[++i]) * (PI / 180.0);
|
| 315 |
break;
|
| 316 |
case 'g':
|
| 317 |
grefl = atof(argv[++i]);
|
| 318 |
break;
|
| 319 |
case 'c':
|
| 320 |
ccover = atof(argv[++i]);
|
| 321 |
break;
|
| 322 |
case 'd':
|
| 323 |
aod = atof(argv[++i]);
|
| 324 |
break;
|
| 325 |
case 'i':
|
| 326 |
sorder = atoi(argv[++i]);
|
| 327 |
break;
|
| 328 |
case 'l':
|
| 329 |
mie_path = argv[++i];
|
| 330 |
break;
|
| 331 |
case 'm':
|
| 332 |
s_meridian = atof(argv[++i]) * (PI / 180.0);
|
| 333 |
break;
|
| 334 |
case 'o':
|
| 335 |
s_longitude = atof(argv[++i]) * (PI / 180.0);
|
| 336 |
break;
|
| 337 |
case 'n':
|
| 338 |
num_threads = atoi(argv[++i]);
|
| 339 |
break;
|
| 340 |
case 'y':
|
| 341 |
year = atoi(argv[++i]);
|
| 342 |
break;
|
| 343 |
case 'f':
|
| 344 |
outname = argv[++i];
|
| 345 |
break;
|
| 346 |
case 'r':
|
| 347 |
res = atoi(argv[++i]);
|
| 348 |
break;
|
| 349 |
default:
|
| 350 |
fprintf(stderr, "Unknown option %s\n", argv[i]);
|
| 351 |
exit(1);
|
| 352 |
}
|
| 353 |
}
|
| 354 |
}
|
| 355 |
|
| 356 |
Atmosphere clear_atmos = init_atmos(aod, grefl);
|
| 357 |
|
| 358 |
int is_summer = (month >= SUMMER_START && month <= SUMMER_END);
|
| 359 |
if (s_latitude < 0) {
|
| 360 |
is_summer = !is_summer;
|
| 361 |
}
|
| 362 |
set_rayleigh_density_profile(&clear_atmos, lstag, is_summer, s_latitude);
|
| 363 |
|
| 364 |
// Load mie density data
|
| 365 |
DATARRAY *mie_dp = getdata(mie_path);
|
| 366 |
if (mie_dp == NULL) {
|
| 367 |
fprintf(stderr, "Error reading mie data\n");
|
| 368 |
return 0;
|
| 369 |
}
|
| 370 |
clear_atmos.beta_m = mie_dp;
|
| 371 |
|
| 372 |
DpPaths clear_paths = get_dppaths(aod, lstag);
|
| 373 |
|
| 374 |
if (getpath(clear_paths.tau, ".", R_OK) == NULL ||
|
| 375 |
getpath(clear_paths.scat, ".", R_OK) == NULL ||
|
| 376 |
getpath(clear_paths.scat1m, ".", R_OK) == NULL ||
|
| 377 |
getpath(clear_paths.irrad, ".", R_OK) == NULL) {
|
| 378 |
printf("# Precomputing...\n");
|
| 379 |
if (!precompute(sorder, clear_paths, &clear_atmos, num_threads)) {
|
| 380 |
fprintf(stderr, "Precompute failed\n");
|
| 381 |
return 0;
|
| 382 |
}
|
| 383 |
}
|
| 384 |
|
| 385 |
DATARRAY *tau_clear_dp = getdata(clear_paths.tau);
|
| 386 |
DATARRAY *irrad_clear_dp = getdata(clear_paths.irrad);
|
| 387 |
DATARRAY *scat_clear_dp = getdata(clear_paths.scat);
|
| 388 |
DATARRAY *scat1m_clear_dp = getdata(clear_paths.scat1m);
|
| 389 |
|
| 390 |
if (!gen_spect_sky(tau_clear_dp, scat_clear_dp, scat1m_clear_dp,
|
| 391 |
irrad_clear_dp, ccover, sundir, grefl, res, outname)) {
|
| 392 |
fprintf(stderr, "gen_spect_sky failed\n");
|
| 393 |
exit(1);
|
| 394 |
}
|
| 395 |
|
| 396 |
freedata(mie_dp);
|
| 397 |
freedata(tau_clear_dp);
|
| 398 |
freedata(scat_clear_dp);
|
| 399 |
freedata(irrad_clear_dp);
|
| 400 |
freedata(scat1m_clear_dp);
|
| 401 |
|
| 402 |
return 1;
|
| 403 |
}
|
