A helper script that manipulates date and time, mainly converting between Julian Day (JD) and Gregorian Date. Utilised by ScreenMaster (extensively), BodyPlotter (a little) and MeteoroidInfo (a little).

Must be assigned to an empty GameObject in the scene, as well as every meteoroid in the scene.

Public Global Variables

void start()
string getDateErrorMessage(string[] dateElements)
double dateToJD(int[] dateElements)
int[] JDToDate(double JD)
string JDToDateString(double JD)
bool daysValid(int day, int month, int year)
int calcDaysInMonth(int month, int year)
bool isALeapYear(int year)

The JD of the start of the program (1/1/2000).
TO DO: change to startJD.

The JD of the end of the program (31/12/2020).
TO DO: change to endJD.

Initialises JD2000 and JD2020.

None

None

• dateToJD(int[] dateElements

• MasterScript.Start()

Conducts the validation on a Gregorian date inputted by the user and returns a message describing the error. If return string == null, then no error occured.

Name	Type	Description
dateElements	string array	A string array of length 3, storing the day, month and year of the Gregorian date.

Name	Type	Description
errorMessage	string	The message describing the user's error. If no error is detected, then the string is set to null and returned.

• daysValid(int day, int month, int year)

• ScreenMaster.changeDateLive(string newDate)
• ScreenMaster.changeDateEnd(string newDate)

Converts a Gregorian date (represented by an array of integers) into a JD. Calculation used is from Astronomical Algorithms, 2nd Ed. by Jean Meeus (p61).

Name	Type	Description
dateElements	int array	The Gregorian date. Has the form {<day>, <month>, <year>}.

Name	Type	Description
JD	double	The JD corresponding to the imported Gregorian date.

None

• start()
• ScreenMaster.changeDateLive(string newDate)

Converts a JD to a Gregorian date (represented by an array of integers). Calculation used is from Astronomical Algorithms, 2nd Ed. by Jean Meeus (p63).

Name	Type	Description
JD	double	The Julian Day.

Name	Type	Description
dateElements	int array	The Gregorian date corresponding to the imported JD. Has the form {<day>, <month>, <year>}.

None

• JDToDateString(string daysElapsed)

Uses JDToDate to convert the imported JD into a Gregorian date. Then constructs a string that the Gregorian date can be read in.

Name	Type	Description
JD	double	The Julian Day.

Name	Type	Description
dateString	string	The date string. Has the format <day>/<month>/<year>. <day> and <month> occupy two digits.

• JDToDate(double JD)

• ScreenMaster.update()
• MeteoroidInfo.setInfoText(string inInfoText)

Confirms that day is within the proper boundaries of its month and year.

Name	Type	Description
day	int	The day of the month. Should be between 1 and 30/31/28/29. If not, we return false.
month	int	The month. Takes values between 1 and 12. We need this to determine an upper limit for day.
year	int	The year. We need this to check if it's a leap year for the specific case of February.

Name	Type	Description
N/A	bool	True if day is within its range, set by month and year. False if not.

• int calcDaysInMonth(int month, int year)

• string getDateErrorMessage(string[] dateElements)

Determines the number of days in month, considering the the possibility that year may be a leap year.

Name	Type	Description
month	int	The month. Takes values between 1 and 12.
year	int	The year. For checking leap year.

Name	Type	Description
daysInMonth	int	The number of days in month.

• bool isALeapYear(int year)

• bool daysValid(int day, int month, int year)

Returns true if year is a leap year and false otherwise.
The conditions of a leap year (according to Gregorian Calendar) are: must be a multiple of 4, BUT not a multiple of 100, UNLESS it's a multiple of 400 (ref.).

Name	Type	Description
year	int	The year that we are checking.

Name	Type	Description
verdict	bool	The verdict of whether year is a leap year or not. True if it is, false if it's not.

None

• int calcDaysInMonth(int month, int year)