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authorMattias Andrée <maandree@member.fsf.org>2016-01-04 21:13:38 +0100
committerMattias Andrée <maandree@member.fsf.org>2016-01-04 21:13:38 +0100
commitdb99d62a8f3ac1c09f4105e60f5be32ad008d3a5 (patch)
treeb5e35927e302c830811c4780a8a8584502bd2d95
parentsplit out from radharc (diff)
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misc
Signed-off-by: Mattias Andrée <maandree@member.fsf.org>
-rw-r--r--src/blackbody.c145
-rw-r--r--src/blackbody.h51
-rw-r--r--src/libred.h (renamed from src/solar.h)57
-rw-r--r--src/macros.h57
-rw-r--r--src/solar.c180
5 files changed, 287 insertions, 203 deletions
diff --git a/src/blackbody.c b/src/blackbody.c
index abe03a9..f45ead4 100644
--- a/src/blackbody.c
+++ b/src/blackbody.c
@@ -14,7 +14,7 @@
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#include "blackbody.h"
+#include "libred.h"
#include "macros.h"
#include <math.h>
#include <errno.h>
@@ -22,6 +22,40 @@
/**
+ * The file descriptor to the colour lookup table.
+ */
+static int fd = -1;
+
+
+
+/**
+ * This function must be called, once,
+ * before calling `libred_get_colour`.
+ *
+ * @return 0 on success, -1 on error.
+ *
+ * @throws Any error specified for `open(3)`.
+ */
+int libred_init_colour(void)
+{
+ libred_term_colour();
+ fd = open(SYSDEPRESDIR "/" PACKAGE "/10deg", O_RDONLY);
+ return fd < 0 ? -1 : 0;
+}
+
+
+/**
+ * Call this when the process will not
+ * longer make calls to `libred_get_colour`.
+ */
+void libred_term_colour(void)
+{
+ if (fd >= 0)
+ close(fd), fd = -1;
+}
+
+
+/**
* Convert from CIE xyY to [0, 1] sRGB.
*
* @param x The 'x' component.
@@ -32,23 +66,22 @@
* @param g Output parameter for the green value.
* @param b Output parameter for the blue value.
*/
-static void
-ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b)
+static void ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b)
{
#define SRGB(C) (((C) <= 0.0031308) ? (12.92 * (C)) : ((1.0 + 0.055) * pow((C), 1.0 / 2.4) - 0.055))
- double X, Z;
-
- /* Convert CIE xyY to CIE XYZ. */
- X = Y * (y == 0.0 ? 0.0 : (x / y));
- Z = Y * (y == 0.0 ? 0.0 : ((1.0 - x - y) / y));
-
- /* Convert CIE XYZ to [0, 1] linear RGB. (ciexyz_to_linear) */
- *r = ( 3.240450 * X) + (-1.537140 * Y) + (-0.4985320 * Z);
- *g = (-0.969266 * X) + ( 1.876010 * Y) + ( 0.0415561 * Z);
- *b = (0.0556434 * X) + (-0.204026 * Y) + ( 1.0572300 * Z);
-
- /* Convert [0, 1] linear RGB to [0, 1] sRGB. */
- SRGB(*r), SRGB(*g), SRGB(*b);
+ double X, Z;
+
+ /* Convert CIE xyY to CIE XYZ. */
+ X = Y * (y == 0.0 ? 0.0 : (x / y));
+ Z = Y * (y == 0.0 ? 0.0 : ((1.0 - x - y) / y));
+
+ /* Convert CIE XYZ to [0, 1] linear RGB. (ciexyz_to_linear) */
+ *r = ( 3.240450 * X) + (-1.537140 * Y) + (-0.4985320 * Z);
+ *g = (-0.969266 * X) + ( 1.876010 * Y) + ( 0.0415561 * Z);
+ *b = (0.0556434 * X) + (-0.204026 * Y) + ( 1.0572300 * Z);
+
+ /* Convert [0, 1] linear RGB to [0, 1] sRGB. */
+ SRGB(*r), SRGB(*g), SRGB(*b);
}
@@ -68,20 +101,18 @@ ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b)
* @param g Output parameter for the green value.
* @param b Output parameter for the blue value.
*/
-static void
-interpolate(double x1, double y1, double x2, double y2, double temp, double *r, double *g, double *b)
+static void interpolate(double x1, double y1, double x2, double y2, double temp, double *r, double *g, double *b)
{
- double weight = fmod(temp, (double)DELTA_TEMPERATURE) / (double)DELTA_TEMPERATURE;
- double x = x1 * (1 - weight) + x2 * weight;
- double y = y1 * (1 - weight) + y2 * weight;
- ciexyy_to_srgb(x, y, 1.0, r, g, b);
+ double weight = fmod(temp, (double)DELTA_TEMPERATURE) / (double)DELTA_TEMPERATURE;
+ double x = x1 * (1 - weight) + x2 * weight;
+ double y = y1 * (1 - weight) + y2 * weight;
+ ciexyy_to_srgb(x, y, 1.0, r, g, b);
}
/**
* Get the [0, 1] sRGB values of a colour temperature.
*
- * @param fd File descriptor for the colour table.
* @param temp The desired colour temperature.
* @param r Output parameter for the “red” value.
* @param g Output parameter for the green value.
@@ -90,41 +121,41 @@ interpolate(double x1, double y1, double x2, double y2, double temp, double *r,
*
* @throws 0 The file did not have the expected size.
* @throws EDOM The selected temperature is below 1000 K.
+ * @throws Any error specified for pread(3).
*/
-int
-get_colour(int fd, long int temp, double *r, double *g, double *b)
+int libred_get_colour(long int temp, double *r, double *g, double *b)
{
- double values[10]; /* low:x,y,r,g,b + high:x,y,r,g,b */
- off_t offset;
- double max;
-
- /* We do not have any values for above 40 000 K, but
- * the differences will be unnoticeable, perhaps even
- * unencodeable. */
- if (temp > HIGHEST_TEMPERATURE) temp = HIGHEST_TEMPERATURE;
- /* Things do not glow below 1000 K. Yes, fire is hot! */
- if (temp < LOWEST_TEMPERATURE) t ((errno = EDOM));
-
- /* Read table. */
- offset = ((off_t)temp - LOWEST_TEMPERATURE) / DELTA_TEMPERATURE;
- offset *= (off_t)(sizeof(values) / 2);
- errno = 0; xpread(fd, values, sizeof(values), offset);
-
- /* Get colour. */
- if (temp % DELTA_TEMPERATURE)
- interpolate(values[0], values[1], values[6], values[7], (double)temp, r, g, b);
- else
- *r = values[2], *g = values[3], *b = values[4];
-
- /* Adjust colours for use. */
- max = fmax(fmax(fabs(*r), fabs(*g)), fabs(*b));
- if (max != 0) *r /= max, *g /= max, *b /= max;
- *r = *r > 0.0 ? *r : 0.0;
- *g = *g > 0.0 ? *g : 0.0;
- *b = *b > 0.0 ? *b : 0.0;
-
- return 0;
-fail:
- return -1;
+ double values[10]; /* low:x,y,r,g,b + high:x,y,r,g,b */
+ off_t offset;
+ double max;
+
+ /* We do not have any values for above 40 000 K, but
+ * the differences will be unnoticeable, perhaps even
+ * unencodeable. */
+ if (temp > HIGHEST_TEMPERATURE) temp = HIGHEST_TEMPERATURE;
+ /* Things do not glow below 1000 K. Yes, fire is hot! */
+ if (temp < LOWEST_TEMPERATURE) t ((errno = EDOM));
+
+ /* Read table. */
+ offset = ((off_t)temp - LOWEST_TEMPERATURE) / DELTA_TEMPERATURE;
+ offset *= (off_t)(sizeof(values) / 2);
+ errno = 0; xpread(fd, values, sizeof(values), offset);
+
+ /* Get colour. */
+ if (temp % DELTA_TEMPERATURE)
+ interpolate(values[0], values[1], values[6], values[7], (double)temp, r, g, b);
+ else
+ *r = values[2], *g = values[3], *b = values[4];
+
+ /* Adjust colours for use. */
+ max = fmax(fmax(fabs(*r), fabs(*g)), fabs(*b));
+ if (max != 0) *r /= max, *g /= max, *b /= max;
+ *r = *r > 0.0 ? *r : 0.0;
+ *g = *g > 0.0 ? *g : 0.0;
+ *b = *b > 0.0 ? *b : 0.0;
+
+ return 0;
+ fail:
+ return -1;
}
diff --git a/src/blackbody.h b/src/blackbody.h
deleted file mode 100644
index 499e9b8..0000000
--- a/src/blackbody.h
+++ /dev/null
@@ -1,51 +0,0 @@
-/**
- * Copyright © 2016 Mattias Andrée <maandree@member.fsf.org>
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-
-
-/**
- * The highest colour temperature in the table.
- */
-#define LIBRED_HIGHEST_TEMPERATURE 40000
-
-/**
- * The lowest colour temperature in the table.
- */
-#define LIBRED_LOWEST_TEMPERATURE 1000
-
-/**
- * The temperature difference between the colours in the table.
- */
-#define LIBRED_DELTA_TEMPERATURE 100
-
-
-
-/**
- * Get the [0, 1] sRGB values of a colour temperature.
- *
- * @param fd File descriptor for the colour table.
- * @param temp The desired colour temperature.
- * @param r Output parameter for the “red” value.
- * @param g Output parameter for the green value.
- * @param b Output parameter for the blue value.
- * @return 0 on succeess, -1 on error.
- *
- * @throws 0 The file did not have the expected size.
- * @throws EDOM The selected temperature is below 1000 K.
- */
-int libred_get_colour(int fd, long int temp, double *r, double *g, double *b);
-
diff --git a/src/solar.h b/src/libred.h
index 8e94cf9..615ed04 100644
--- a/src/solar.h
+++ b/src/libred.h
@@ -14,6 +14,9 @@
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#ifndef LIBRED_H
+#define LIBRED_H
+
/**
@@ -105,3 +108,57 @@ int libred_check_timetravel(void);
# define libred_check_timetravel() 0
#endif
+
+
+/**
+ * The highest colour temperature in the table.
+ */
+#define LIBRED_HIGHEST_TEMPERATURE 40000
+
+/**
+ * The lowest colour temperature in the table.
+ */
+#define LIBRED_LOWEST_TEMPERATURE 1000
+
+/**
+ * The temperature difference between the colours in the table.
+ */
+#define LIBRED_DELTA_TEMPERATURE 100
+
+
+
+/**
+ * This function must be called, once,
+ * before calling `libred_get_colour`.
+ *
+ * @return 0 on success, -1 on error.
+ *
+ * @throws Any error specified for `open(3)`.
+ */
+int libred_init_colour(void);
+
+/**
+ * Call this when the process will not
+ * longer make calls to `libred_get_colour`.
+ */
+void libred_term_colour(void);
+
+/**
+ * Get the [0, 1] sRGB values of a colour temperature.
+ *
+ * @param temp The desired colour temperature.
+ * @param r Output parameter for the “red” value.
+ * @param g Output parameter for the green value.
+ * @param b Output parameter for the blue value.
+ * @return 0 on succeess, -1 on error.
+ *
+ * @throws 0 The file did not have the expected size.
+ * @throws EDOM The selected temperature is below 1000 K.
+ * @throws Any error specified for pread(3).
+ */
+int libred_get_colour(long int temp, double *r, double *g, double *b);
+
+
+
+#endif
+
diff --git a/src/macros.h b/src/macros.h
new file mode 100644
index 0000000..c0aeabb
--- /dev/null
+++ b/src/macros.h
@@ -0,0 +1,57 @@
+/**
+ * Copyright © 2016 Mattias Andrée <maandree@member.fsf.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+
+
+#define try(...) do { if (!(__VA_ARGS__)) goto fail; } while (0)
+#define t(...) do { if (__VA_ARGS__) goto fail; } while (0)
+#define CLEANUP(...) do { int cleanup__ = errno; __VA_ARGS__; errno = cleanup__; } while (0)
+
+#define xstrdup(outp, ...) \
+do { \
+ const char *xstrdup__ = (__VA_ARGS__); \
+ if (xstrdup__) \
+ try (*(outp) = strdup(xstrdup__)); \
+ else \
+ *(outp) = NULL; \
+} while (0)
+
+#define xpread(fd, buf, len, off) t (pread(fd, buf, len, off) < (ssize_t)(len))
+#define xpwrite(fd, buf, len, off) t (pwrite(fd, buf, len, off) < (ssize_t)(len))
+#define xread(fd, buf, len) t (read(fd, buf, len) < (ssize_t)(len))
+#define xwrite(fd, buf, len) t (write(fd, buf, len) < (ssize_t)(len))
+
+#define xcalloc(outp, num) try (*(outp) = calloc(num, sizeof(**(outp))))
+#define xmalloc(outp, num) try (*(outp) = malloc((num) * sizeof(**(outp))))
+#define xrealloc(outp, num) \
+do { \
+ size_t n__ = (num); \
+ void *new__ = realloc(*(outp), n__ * sizeof(**(outp))); \
+ t (n__ && !new__); \
+ *(outp) = new__; \
+} while (0)
+
+#define SHRINK(outp, num) \
+do { \
+ void *new__ = realloc(*(outp), (num) * sizeof(**(outp))); \
+ if (new__) *(outp) = new__; \
+} while (0)
+
diff --git a/src/solar.c b/src/solar.c
index 8a57507..697ecd6 100644
--- a/src/solar.c
+++ b/src/solar.c
@@ -13,14 +13,21 @@
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * This file is a stripped down port of <https://github.com/maandree/solar-python>.
*/
+#include "libred.h"
#include <math.h>
#include <time.h>
#include <errno.h>
-#if !defined(CLOCK_REALTIME_COARSE)
+/* Select clock. */
+#if defined(DO_NOT_USE_COARSEC_CLOCK) || !defined(CLOCK_REALTIME_COARSE)
+# ifdef CLOCK_REALTIME_COARSE
+# undef CLOCK_REALTIME_COARSE
+# endif
# define CLOCK_REALTIME_COARSE CLOCK_REALTIME
#endif
@@ -34,15 +41,14 @@
* @throws 0 On success.
* @throws Any error specified for clock_gettime(3) on error.
*/
-static double
-julian_centuries()
+static double julian_centuries()
{
- struct timespec now;
- double tm;
- if (clock_gettime(CLOCK_REALTIME_COARSE, &now)) return 0.0;
- tm = (double)(now.tv_nsec) / 1000000000.0 + (double)(now.tv_sec);
- tm = (tm / 86400.0 + 2440587.5 - 2451545.0) / 36525.0;
- return errno = 0, tm;
+ struct timespec now;
+ double tm;
+ if (clock_gettime(CLOCK_REALTIME_COARSE, &now)) return 0.0;
+ tm = (double)(now.tv_nsec) / 1000000000.0 + (double)(now.tv_sec);
+ tm = (tm / 86400.0 + 2440587.5 - 2451545.0) / 36525.0;
+ return errno = 0, tm;
}
/**
@@ -51,10 +57,9 @@ julian_centuries()
* @param tm The time in Julian Centuries
* @return The time in Julian Days
*/
-static inline double
-julian_centuries_to_julian_day(double tm)
+static inline double julian_centuries_to_julian_day(double tm)
{
- return tm * 36525.0 + 2451545.0;
+ return tm * 36525.0 + 2451545.0;
}
@@ -64,10 +69,9 @@ julian_centuries_to_julian_day(double tm)
* @param deg The angle in degrees.
* @param The angle in radians.
*/
-static inline double
-radians(double deg)
+static inline double radians(double deg)
{
- return deg * (double)M_PI / 180.0;
+ return deg * (double)M_PI / 180.0;
}
/**
@@ -76,10 +80,9 @@ radians(double deg)
* @param rad The angle in radians.
* @param The angle in degrees.
*/
-static inline double
-degrees(double rad)
+static inline double degrees(double rad)
{
- return rad * 180.0 / (double)M_PI;
+ return rad * 180.0 / (double)M_PI;
}
@@ -92,13 +95,12 @@ degrees(double rad)
* @param hour_angle The solar hour angle, in radians.
* @return The Sun's elevation, in radians.
*/
-static inline double
-elevation_from_hour_angle(double latitude, double declination, double hour_angle)
+static inline double elevation_from_hour_angle(double latitude, double declination, double hour_angle)
{
- double rc = cos(radians(latitude));
- rc *= cos(hour_angle) * cos(declination);
- rc += sin(radians(latitude)) * sin(declination);
- return asin(rc);
+ double rc = cos(radians(latitude));
+ rc *= cos(hour_angle) * cos(declination);
+ rc += sin(radians(latitude)) * sin(declination);
+ return asin(rc);
}
/**
@@ -107,14 +109,13 @@ elevation_from_hour_angle(double latitude, double declination, double hour_angle
* @param tm The time in Julian Centuries.
* @return The Sun's geometric mean longitude in radians.
*/
-static inline double
-sun_geometric_mean_longitude(double tm)
+static inline double sun_geometric_mean_longitude(double tm)
{
- double rc = fmod(pow(0.0003032 * tm, 2.0) + 36000.76983 * tm + 280.46646, 360.0);
+ double rc = fmod(pow(0.0003032 * tm, 2.0) + 36000.76983 * tm + 280.46646, 360.0);
#if defined(TIMETRAVELLER)
- rc = rc < 0.0 ? (rc + 360.0) : rc;
+ rc = rc < 0.0 ? (rc + 360.0) : rc;
#endif
- return radians(rc);
+ return radians(rc);
}
/**
@@ -123,10 +124,9 @@ sun_geometric_mean_longitude(double tm)
* @param tm The time in Julian Centuries.
* @return The Sun's geometric mean anomaly in radians.
*/
-static inline double
-sun_geometric_mean_anomaly(double tm)
+static inline double sun_geometric_mean_anomaly(double tm)
{
- return radians(pow(-0.0001537 * tm, 2.0) + 35999.05029 * tm + 357.52911);
+ return radians(pow(-0.0001537 * tm, 2.0) + 35999.05029 * tm + 357.52911);
}
/**
@@ -135,10 +135,9 @@ sun_geometric_mean_anomaly(double tm)
* @param tm The time in Julian Centuries.
* @return The Earth's orbit eccentricity.
*/
-static inline double
-earth_orbit_eccentricity(double tm)
+static inline double earth_orbit_eccentricity(double tm)
{
- return pow(-0.0000001267 * tm, 2.0) - 0.000042037 * tm + 0.016708634;
+ return pow(-0.0000001267 * tm, 2.0) - 0.000042037 * tm + 0.016708634;
}
/**
@@ -148,14 +147,13 @@ earth_orbit_eccentricity(double tm)
* @param tm The time in Julian Centuries.
* @return The Sun's equation of the centre, in radians.
*/
-static inline double
-sun_equation_of_centre(double tm)
+static inline double sun_equation_of_centre(double tm)
{
- double a = sun_geometric_mean_anomaly(tm), rc;
- rc = sin(1.0 * a) * (pow(-0.000014 * tm, 2.0) - 0.004817 * tm + 1.914602);
- rc += sin(2.0 * a) * (-0.000101 * tm + 0.019993);
- rc += sin(3.0 * a) * 0.000289;
- return radians(rc);
+ double a = sun_geometric_mean_anomaly(tm), rc;
+ rc = sin(1.0 * a) * (pow(-0.000014 * tm, 2.0) - 0.004817 * tm + 1.914602);
+ rc += sin(2.0 * a) * (-0.000101 * tm + 0.019993);
+ rc += sin(3.0 * a) * 0.000289;
+ return radians(rc);
}
/**
@@ -164,10 +162,9 @@ sun_equation_of_centre(double tm)
* @param tm The time in Julian Centuries.
* @return The longitude, in radians.
*/
-static inline double
-sun_real_longitude(double tm)
+static inline double sun_real_longitude(double tm)
{
- return sun_geometric_mean_longitude(tm) + sun_equation_of_centre(tm);
+ return sun_geometric_mean_longitude(tm) + sun_equation_of_centre(tm);
}
/**
@@ -176,11 +173,10 @@ sun_real_longitude(double tm)
* @param tm The time in Julian Centuries.
* @return The longitude, in radians.
*/
-static inline double
-sun_apparent_longitude(double tm)
+static inline double sun_apparent_longitude(double tm)
{
- double rc = degrees(sun_real_longitude(tm)) - 0.00569;
- return radians(rc - 0.00478 * sin(radians(-1934.136 * tm + 125.04)));
+ double rc = degrees(sun_real_longitude(tm)) - 0.00569;
+ return radians(rc - 0.00478 * sin(radians(-1934.136 * tm + 125.04)));
}
/**
@@ -190,11 +186,10 @@ sun_apparent_longitude(double tm)
* @param tm The time in Julian Centuries.
* @return The uncorrected mean obliquity, in radians.
*/
-static double
-mean_ecliptic_obliquity(double tm)
+static double mean_ecliptic_obliquity(double tm)
{
- double rc = pow(0.001813 * tm, 3.0) - pow(0.00059 * tm, 2.0) - 46.815 * tm + 21.448;
- return radians(23.0 + (26.0 + rc / 60.0) / 60.0);
+ double rc = pow(0.001813 * tm, 3.0) - pow(0.00059 * tm, 2.0) - 46.815 * tm + 21.448;
+ return radians(23.0 + (26.0 + rc / 60.0) / 60.0);
}
/**
@@ -204,11 +199,10 @@ mean_ecliptic_obliquity(double tm)
* @param tm The time in Julian Centuries.
* @return The mean obliquity, in radians.
*/
-static double
-corrected_mean_ecliptic_obliquity(double tm)
+static double corrected_mean_ecliptic_obliquity(double tm)
{
- double rc = 0.00256 * cos(radians(-1934.136 * tm + 125.04));
- return radians(rc + degrees(mean_ecliptic_obliquity(tm)));
+ double rc = 0.00256 * cos(radians(-1934.136 * tm + 125.04));
+ return radians(rc + degrees(mean_ecliptic_obliquity(tm)));
}
/**
@@ -217,11 +211,10 @@ corrected_mean_ecliptic_obliquity(double tm)
* @param tm The time in Julian Centuries.
* @return The Sun's declination, in radian.
*/
-static inline double
-solar_declination(double tm)
+static inline double solar_declination(double tm)
{
- double rc = sin(corrected_mean_ecliptic_obliquity(tm));
- return asin(rc * sin(sun_apparent_longitude(tm)));
+ double rc = sin(corrected_mean_ecliptic_obliquity(tm));
+ return asin(rc * sin(sun_apparent_longitude(tm)));
}
/**
@@ -231,18 +224,17 @@ solar_declination(double tm)
* @param tm The time in Julian Centuries.
* @return The equation of time, in degrees.
*/
-static inline double
-equation_of_time(double tm)
+static inline double equation_of_time(double tm)
{
- double l = sun_geometric_mean_longitude(tm);
- double e = earth_orbit_eccentricity(tm);
- double m = sun_geometric_mean_anomaly(tm);
- double y = pow(tan(corrected_mean_ecliptic_obliquity(tm) / 2.0), 2.0);
- double rc = y * sin(2.0 * l);
- rc += (4.0 * y * cos(2.0 * l) - 2.0) * e * sin(m);
- rc -= pow(0.5 * y, 2.0) * sin(4.0 * l);
- rc -= pow(1.25 * e, 2.0) * sin(2.0 * m);
- return 4.0 * degrees(rc);
+ double l = sun_geometric_mean_longitude(tm);
+ double e = earth_orbit_eccentricity(tm);
+ double m = sun_geometric_mean_anomaly(tm);
+ double y = pow(tan(corrected_mean_ecliptic_obliquity(tm) / 2.0), 2.0);
+ double rc = y * sin(2.0 * l);
+ rc += (4.0 * y * cos(2.0 * l) - 2.0) * e * sin(m);
+ rc -= pow(0.5 * y, 2.0) * sin(4.0 * l);
+ rc -= pow(1.25 * e, 2.0) * sin(2.0 * m);
+ return 4.0 * degrees(rc);
}
/**
@@ -257,14 +249,13 @@ equation_of_time(double tm)
* @return The Sun's apparent elevation at the specified time as seen
* from the specified position, measured in radians.
*/
-static inline double
-solar_elevation_from_time(double tm, double latitude, double longitude)
+static inline double solar_elevation_from_time(double tm, double latitude, double longitude)
{
- double rc = julian_centuries_to_julian_day(tm);
- rc = (rc - round(rc) - 0.5) * 1440;
- rc = 720.0 - rc - equation_of_time(tm);
- rc = radians(rc / 4.0 - longitude);
- return elevation_from_hour_angle(latitude, solar_declination(tm), rc);
+ double rc = julian_centuries_to_julian_day(tm);
+ rc = (rc - round(rc) - 0.5) * 1440;
+ rc = 720.0 - rc - equation_of_time(tm);
+ rc = radians(rc / 4.0 - longitude);
+ return elevation_from_hour_angle(latitude, solar_declination(tm), rc);
}
@@ -282,11 +273,10 @@ solar_elevation_from_time(double tm, double latitude, double longitude)
* @throws 0 On success.
* @throws Any error specified for clock_gettime(3) on error.
*/
-double
-solar_elevation(double latitude, double longitude)
+double libred_solar_elevation(double latitude, double longitude)
{
- double tm = julian_centuries();
- return errno ? -1 : degrees(solar_elevation_from_time(tm, latitude, longitude));
+ double tm = julian_centuries();
+ return errno ? -1 : degrees(solar_elevation_from_time(tm, latitude, longitude));
}
@@ -295,18 +285,18 @@ solar_elevation(double latitude, double longitude)
*
* @return 0 on success, -1 on error.
*/
-#if defined(TIMETRAVELLER)
-int
-check_timetravel(void)
+int libred_check_timetravel(void)
{
- struct timespec now;
- if (clock_gettime(CLOCK_REALTIME, &now)) return -1;
- if (now.tv_nsec < (time_t)946728000L)
- fprintf(stderr, "We have detected that you are a time-traveller"
- "(or your clock is not configured correctly.)"
- "Please recompile with -DTIMETRAVELLER"
- "(or correct your clock.)"), exit(1);
- return 0;
-}
+#if !defined(TIMETRAVELLER)
+ struct timespec now;
+ if (clock_gettime(CLOCK_REALTIME, &now)) return -1;
+ if (now.tv_nsec < (time_t)946728000L)
+ fprintf(stderr,
+ "We have detected that you are a time-traveller"
+ "(or your clock is not configured correctly.)"
+ "Please recompile libred with -DTIMETRAVELLER"
+ "(or correct your clock.)"), exit(1);
#endif
+ return 0;
+}