From 52a5a370fd394585d4bbf69d4a637bf92bd5878d Mon Sep 17 00:00:00 2001 From: Jon Lund Steffensen Date: Thu, 6 May 2010 23:56:52 +0200 Subject: systemtime.c: Portably read current time on posix and windows. w32gdi.c: Implements gamma ramp method for Windows GDI API. Use double as a cross platform time representation. Add WinGDI as a selectable method (currently limitied to minimum 4500K). Fix a bug where redshift would crash if RANDR failed and VidMode wasn't compiled in. --- src/solar.c | 42 ++++++++++++++++++++++-------------------- 1 file changed, 22 insertions(+), 20 deletions(-) (limited to 'src/solar.c') diff --git a/src/solar.c b/src/solar.c index 9b63c40..9b2b59d 100644 --- a/src/solar.c +++ b/src/solar.c @@ -24,9 +24,9 @@ Jean Meeus. */ #include -#include #include "solar.h" +#include "time.h" #define RAD(x) ((x)*(M_PI/180)) #define DEG(x) ((x)*(180/M_PI)) @@ -46,23 +46,20 @@ static const double time_angle[] = { }; -/* Unix time from Julian day */ -static struct timespec -timespec_from_jd(double jd) +/* Unix epoch from Julian day */ +static double +epoch_from_jd(double jd) { - struct timespec t; - double secs = 86400.0*(jd - 2440587.5); - t.tv_sec = floor(secs); - t.tv_nsec = (secs - t.tv_sec) * 1000000000.0; - return t; + return 86400.0*(jd - 2440587.5); } -/* Julian day from unix time */ + + +/* Julian day from unix epoch */ static double -jd_from_timespec(struct timespec t) +jd_from_epoch(double t) { - return (t.tv_sec / 86400.0) + - (t.tv_nsec / 86400000000000.0) + 2440587.5; + return (t / 86400.0) + 2440587.5; } /* Julian centuries since J2000.0 from Julian day */ @@ -287,18 +284,23 @@ solar_elevation_from_time(double t, double lat, double lon) return elevation_from_hour_angle(lat, decl, ha); } +/* Solar angular elevation at the given location and time. + date: Seconds since unix epoch + lat: Latitude of location + lon: Longitude of location + Return: Solar angular elevation in degrees */ double -solar_elevation(struct timespec date, double lat, double lon) +solar_elevation(double date, double lat, double lon) { - double jd = jd_from_timespec(date); + double jd = jd_from_epoch(date); return DEG(solar_elevation_from_time(jcent_from_jd(jd), lat, lon)); } void -solar_table_fill(struct timespec date, double lat, double lon, time_t *table) +solar_table_fill(double date, double lat, double lon, double *table) { /* Calculate Julian day */ - double jd = jd_from_timespec(date); + double jd = jd_from_epoch(date); /* Calculate Julian day number */ double jdn = round(jd); @@ -308,16 +310,16 @@ solar_table_fill(struct timespec date, double lat, double lon, time_t *table) double sol_noon = time_of_solar_noon(t, lon); double j_noon = jdn - 0.5 + sol_noon/1440.0; double t_noon = jcent_from_jd(j_noon); - table[SOLAR_TIME_NOON] = timespec_from_jd(j_noon).tv_sec; + table[SOLAR_TIME_NOON] = epoch_from_jd(j_noon); /* Calculate solar midnight */ - table[SOLAR_TIME_MIDNIGHT] = timespec_from_jd(j_noon + 0.5).tv_sec; + table[SOLAR_TIME_MIDNIGHT] = epoch_from_jd(j_noon + 0.5); /* Calulate absoute time of other phenomena */ for (int i = 2; i < SOLAR_TIME_MAX; i++) { double angle = time_angle[i]; double offset = time_of_solar_elevation(t, t_noon, lat, lon, angle); - table[i] = timespec_from_jd(jdn - 0.5 + offset/1440.0).tv_sec; + table[i] = epoch_from_jd(jdn - 0.5 + offset/1440.0); } } -- cgit v1.2.3-70-g09d2