aqhome-react: added code to determine sunset/sunrise times.

apps/aqhome-react/0BUILD

@@ -43,6 +43,7 @@
       fini.h
       loop.h
       net_read.h
+      suntimes.h
     </headers>
   
     <sources>
@@ -52,6 +53,7 @@
       fini.c
       loop.c
       net_read.c
+      suntimes.c
       main.c
     </sources>
 
@@ -63,6 +65,7 @@
 
     <libraries>
       $(gwenhywfar_libs)
+      -lm
     </libraries>
 
     <subdirs>

apps/aqhome-react/suntimes.c

@@ -0,0 +1,203 @@
+/****************************************************************************
+ * This file is part of the project AqHome.
+ * AqHome (c) by 2024 Martin Preuss, all rights reserved.
+ *
+ * The license for this file can be found in the file COPYING which you
+ * should have received along with this file.
+ ****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "./suntimes.h"
+
+#include <stdio.h>
+#include <math.h>
+
+
+
+/* ------------------------------------------------------------------------------------------------
+ * forward declarations
+ * ------------------------------------------------------------------------------------------------
+ */
+
+static GWEN_TIME *_getSunTime(const GWEN_DATE *date, double lat, double lng, int calcSunrise);
+static double _calcSunTime(const GWEN_DATE *date, double lat, double lng, int calcSunrise);
+
+
+
+/* ------------------------------------------------------------------------------------------------
+ * implementations
+ * ------------------------------------------------------------------------------------------------
+ */
+
+GWEN_TIME *AQHomeReact_GetSunriseTimeForDateAndLoc(const GWEN_DATE *date, double lat, double lng)
+{
+  return _getSunTime(date, lat, lng, 1);
+}
+
+
+GWEN_TIME *AQHomeReact_GetSunsetTimeForDateAndLoc(const GWEN_DATE *date, double lat, double lng)
+{
+  return _getSunTime(date, lat, lng, 0);
+}
+
+
+GWEN_TIME *_getSunTime(const GWEN_DATE *date, double lat, double lng, int calcSunrise)
+{
+  double timeInFloat=fmod(24+_calcSunTime(date, lat, lng, calcSunrise), 24);
+  double hours;
+  double minutes = modf(timeInFloat, &hours)*60;
+  GWEN_TIME *ti=GWEN_Time_new(GWEN_Date_GetYear(date), GWEN_Date_GetMonth(date)-1, GWEN_Date_GetDay(date),
+			      hours, minutes, 0, 1);
+  return ti;
+}
+
+
+
+#if 0
+int _test(void) {
+  double lat       = 52.619425; // Latitude of location.
+  double lng       = 10.087891;  // Longitude of location.
+  int y=2024;
+  int m=4;
+  int d;
+
+  for (d=19; d<=24; d++) {
+    GWEN_DATE *date;
+    GWEN_TIME *sunrise;
+    GWEN_TIME *sunset;
+    int sunsetHours, sunsetMinutes, sunsetSecs;
+    int sunriseHours, sunriseMinutes, sunriseSecs;
+
+    date=GWEN_Date_fromGregorian(y, m, d);
+    sunrise=AQHomeReact_GetSunriseTimeForDateAndLoc(date, lat, lng);
+    sunset=AQHomeReact_GetSunsetTimeForDateAndLoc(date, lat, lng);
+
+    GWEN_Time_GetBrokenDownTime(sunset, &sunsetHours, &sunsetMinutes, &sunsetSecs);
+    GWEN_Time_GetBrokenDownTime(sunrise, &sunriseHours, &sunriseMinutes, &sunriseSecs);
+
+    fprintf(stdout, "date=%04d-%02d-%02d: sunrise=%02d:%02d sunset=%02d:%02d\n",
+	    GWEN_Date_GetYear(date), GWEN_Date_GetMonth(date), GWEN_Date_GetDay(date),
+	    sunriseHours, sunriseMinutes,
+	    sunsetHours, sunsetMinutes);
+    GWEN_Time_free(sunset);
+    GWEN_Time_free(sunrise);
+    GWEN_Date_free(date);
+  }
+}
+#endif
+
+
+
+/**
+ * Calculate time of sunset or sunrise at a given position and date according to an algorithm presented
+ * on this site:
+ *   http://edwilliams.org/sunrise_sunset_algorithm.htm
+ *
+ * Original notes follow.
+ *
+ * -----------------------------
+ * Source:
+ *   Almanac for Computers, 1990
+ *   published by Nautical Almanac Office
+ *   United States Naval Observatory
+ *   Washington, DC 20392
+ *
+ * Inputs:
+ *  date    : date for which to calculate sun time
+ *  lat, lng: latitude and longitude of the location to calculate for (west and north are positive values)
+ *  ZENITH  : Sun's zenith for sunrise/sunset
+ *            official = 90 degrees 50'
+ *            civil    = 96 degrees
+ *            nautical     = 102 degrees
+ *            astronomical = 108 degrees
+ *
+ * NOTE: longitude is positive for East and negative for West
+ * NOTE: the algorithm assumes the use of a calculator with the
+ *       trig functions in "degree" (rather than "radian") mode. Most
+ *       programming languages assume radian arguments, requiring back
+ *       and forth convertions. The factor is 180/pi. So, for instance,
+ *       the equation RA = atan(0.91764 * tan(L)) would be coded as RA
+ *       = (180/pi)*atan(0.91764 * tan((pi/180)*L)) to give a degree
+ *       answer with a degree input for L.
+*/
+double _calcSunTime(const GWEN_DATE *date, double lat, double lng, int calcSunrise)
+{
+  const double PI=3.1415926535897932384626433832795;
+  const double ZENITH=-.83;  /* accounts for atmospheric refraction (assuming height of 0m above horizon) */
+  double PiBy180=PI/180.0;
+  double N;
+  double lngHour;
+  double t;
+  double M;
+  double L;
+  double RA;
+  double Lquadrant;
+  double RAquadrant;
+  double sinDec;
+  double cosDec;
+  double cosH;
+  double H;
+  double T;
+  double UT;
+
+  /* 1. first calculate the day of the year */
+  N=GWEN_Date_DaysInYear(date);
+
+  /* 2. convert the longitude to hour value and calculate an approximate time */
+  lngHour = lng/15.0;
+  if (calcSunrise)
+    t = N+((6-lngHour)/24);
+  else
+    t = N+((18-lngHour)/24);
+
+  /* 3. calculate the Sun's mean anomaly */
+  M = (0.9856*t)-3.289;
+
+  /* 4. calculate the Sun's true longitude */
+  L = fmod(M+(1.916*sin(PiBy180*M)) + (0.020 * sin(2*PiBy180*M)) + 282.634, 360.0);
+
+  /* 5a. calculate the Sun's right ascension */
+  RA = fmod(180/PI*atan(0.91764*tan(PiBy180*L)), 360.0);
+
+  /* 5b. right ascension value needs to be in the same quadrant as L */
+  Lquadrant = floor(L/90)*90;
+  RAquadrant = floor(RA/90)*90;
+  RA = RA + (Lquadrant-RAquadrant);
+
+  /* 5c. right ascension value needs to be converted into hours */
+  RA = RA / 15;
+
+  /* 6. calculate the Sun's declination */
+  sinDec = 0.39782*sin(PiBy180*L);
+  cosDec = cos(asin(sinDec));
+
+  /* 7a. calculate the Sun's local hour angle */
+  cosH = (sin(PiBy180*ZENITH)-(sinDec*sin(PiBy180*lat))) / (cosDec*cos(PiBy180*lat));
+  /* cosH >1 : sun never rises on this location and date
+   * cosH <-1: sun never sets on this location and date
+   */
+
+  /* 7b. finish calculating H and convert into hours */
+  if (calcSunrise)
+    H = 360-(180/PI)*acos(cosH);
+  else
+    H = (180/PI)*acos(cosH);
+  H = H/15;
+
+  /* 8. calculate local mean time of rising/setting */
+  T = H+RA-(0.06571*t)-6.622;
+
+  /* 9. adjust back to UTC */
+  UT = fmod(T-lngHour, 24.0);
+
+  /* we don't do step 10. here which would be to convert UT into local time as we want UTC */
+  return UT;
+}
+
+
+
+
+

apps/aqhome-react/suntimes.h

@@ -0,0 +1,49 @@
+/****************************************************************************
+ * This file is part of the project AqHome.
+ * AqHome (c) by 2024 Martin Preuss, all rights reserved.
+ *
+ * The license for this file can be found in the file COPYING which you
+ * should have received along with this file.
+ ****************************************************************************/
+
+#ifndef AQHOMEREACT_SUNTIMES_H
+#define AQHOMEREACT_SUNTIMES_H
+
+
+#include "./aqhome_react.h"
+
+#include <gwenhywfar/gwendate.h>
+#include <gwenhywfar/gwentime.h>
+
+
+/**
+ * Returns the sunrise time on the provided day and location.
+ *
+ * You can get the location by just clicking on a position on your chosen map website (e.g. "G'maps").
+ *
+ * @return time of sunrise for the given date and location
+ * @param date date for which to calculate
+ * @param lat latitude of the location to calculate for (positive for east)
+ * @param lng longitude  of the location to calculate for (positive for north)
+*/
+GWEN_TIME *AQHomeReact_GetSunriseTimeForDateAndLoc(const GWEN_DATE *date, double lat, double lng);
+
+
+/**
+ * Returns the sunset time on the provided day and location.
+ *
+ * You can get the location by just clicking on a position on your chosen map website (e.g. "G'maps").
+ *
+ * @return time of sunset for the given date and location
+ * @param date date for which to calculate
+ * @param lat latitude of the location to calculate for (positive for east)
+ * @param lng longitude  of the location to calculate for (positive for north)
+*/
+GWEN_TIME *AQHomeReact_GetSunsetTimeForDateAndLoc(const GWEN_DATE *date, double lat, double lng);
+
+
+
+
+#endif
+
+