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systemtime.c: Portably read current time on posix and windows.

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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.
This commit is contained in:
Jon Lund Steffensen
2010-05-06 23:56:52 +02:00
parent fc47840a2c
commit 52a5a370fd
9 changed files with 402 additions and 52 deletions
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src/solar.c
+22 -20
View File
@@ -24,9 +24,9 @@
Jean Meeus. */
#include <math.h>
#include <time.h>
#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);
}
}