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/* Copyright (c) 1986 Regents of the University of California */ |
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/* Copyright (c) 1992 Regents of the University of California */ |
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#include "color.h" |
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#ifndef atof |
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extern double atof(); |
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#endif |
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extern char *strcpy(), *strcat(), *malloc(); |
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extern double stadj(), sdec(), sazi(), salt(); |
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/* default values */ |
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int cloudy = 0; /* 1=standard, 2=uniform */ |
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int dosun = 1; |
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double zenithbr = -1.0; |
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double zenithbr = 0.0; |
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int u_zenith = 0; /* -1=irradiance, 1=radiance */ |
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double turbidity = 2.75; |
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double gprefl = 0.2; |
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/* computed values */ |
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double sundir[3]; |
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double groundbr; |
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double F2; |
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double solarbr; |
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double solarbr = 0.0; |
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int u_solar = 0; /* -1=irradiance, 1=radiance */ |
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char *progname; |
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char errmsg[128]; |
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cloudy = 0; |
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dosun = argv[i][0] == '+'; |
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break; |
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case 'r': |
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case 'R': |
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u_solar = argv[i][1]=='R' ? -1 : 1; |
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solarbr = atof(argv[++i]); |
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break; |
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case 'c': |
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cloudy = argv[i][0] == '+' ? 2 : 1; |
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dosun = 0; |
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turbidity = atof(argv[++i]); |
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break; |
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case 'b': |
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case 'B': |
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u_zenith = argv[i][1]=='B' ? -1 : 1; |
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zenithbr = atof(argv[++i]); |
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break; |
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case 'g': |
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computesky() /* compute sky parameters */ |
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{ |
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double normfactor; |
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/* compute solar direction */ |
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if (month) { /* from date and time */ |
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int jd; |
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st = hour + stadj(jd); |
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altitude = salt(sd, st); |
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azimuth = sazi(sd, st); |
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printf("# Solar altitude and azimuth: %f %f\n", |
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180./PI*altitude, 180./PI*azimuth); |
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} |
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if (!cloudy && altitude > 87.*PI/180.) { |
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fprintf(stderr, |
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"%s: warning - sun too close to zenith, reducing altitude to 87 degrees\n", |
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progname); |
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printf( |
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"# warning - sun too close to zenith, reducing altitude to 87 degrees\n"); |
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altitude = 87.*PI/180.; |
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} |
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sundir[0] = -sin(azimuth)*cos(altitude); |
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sundir[1] = -cos(azimuth)*cos(altitude); |
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sundir[2] = sin(altitude); |
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/* Compute normalization factor */ |
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if (cloudy == 2) |
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normfactor = 1.0; |
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else if (cloudy == 1) |
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normfactor = 0.777778; |
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else { |
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F2 = 0.274*(0.91 + 10.0*exp(-3.0*(PI/2.0-altitude)) + |
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0.45*sundir[2]*sundir[2]); |
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normfactor = normsc(altitude)/F2/PI; |
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} |
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/* Compute zenith brightness */ |
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if (zenithbr <= 0.0) |
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if (cloudy) { |
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if (u_zenith == -1) |
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zenithbr /= normfactor*PI; |
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else if (u_zenith == 0) { |
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if (cloudy) |
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zenithbr = 8.6*sundir[2] + .123; |
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zenithbr *= 1000.0/WHTEFFICACY; |
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} else { |
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else |
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zenithbr = (1.376*turbidity-1.81)*tan(altitude)+0.38; |
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zenithbr *= 1000.0/SKYEFFICACY; |
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} |
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if (zenithbr < 0.0) |
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zenithbr = 0.0; |
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/* Compute horizontal radiance */ |
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if (cloudy) { |
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if (cloudy == 2) |
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groundbr = zenithbr; |
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if (zenithbr < 0.0) |
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zenithbr = 0.0; |
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else |
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groundbr = zenithbr*0.777778; |
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printf("# Ground ambient level: %f\n", groundbr); |
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} else { |
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F2 = 0.274*(0.91 + 10.0*exp(-3.0*(PI/2.0-altitude)) + |
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0.45*sundir[2]*sundir[2]); |
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groundbr = zenithbr*normsc(altitude)/F2/PI; |
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printf("# Ground ambient level: %f\n", groundbr); |
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if (sundir[2] > 0.0) { |
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if (sundir[2] > .16) |
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solarbr = (1.5e9/SUNEFFICACY) * |
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(1.147 - .147/sundir[2]); |
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else |
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solarbr = 1.5e9/SUNEFFICACY*(1.147-.147/.16); |
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groundbr += solarbr*6e-5*sundir[2]/PI; |
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} else |
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dosun = 0; |
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zenithbr *= 1000.0/SKYEFFICACY; |
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} |
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/* Compute horizontal radiance */ |
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groundbr = zenithbr*normfactor; |
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printf("# Ground ambient level: %f\n", groundbr); |
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if (sundir[2] > 0.0 && (!u_solar || solarbr > 0.0)) { |
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if (u_solar == -1) |
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solarbr /= 6e-5*sundir[2]; |
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else if (u_solar == 0) |
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solarbr = 1.5e9/SUNEFFICACY * |
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(1.147 - .147/(sundir[2]>.16?sundir[2]:.16)); |
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groundbr += 6e-5/PI*solarbr*sundir[2]; |
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} else |
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dosun = 0; |
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groundbr *= gprefl; |
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} |
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