The rise and fall of a semidiurnal tide, from a plain running minute count. More...

#include "clock/tide.h"

Macros
#define	TIDE_PERIOD_CUBE ((int64_t)TIDE_PERIOD_MIN * TIDE_PERIOD_MIN * TIDE_PERIOD_MIN)
	The cycle's length cubed, which the smoothstep divides by.

Functions
static int32_t	phase (int32_t minutes)
	Where in the cycle a minute count lands.
int	tide_level (int32_t minutes)
	How far in the tide is, from 0 at dead low to 100 at high water.
bool	tide_rising (int32_t minutes)
	Whether the tide is on its way in.

Detailed Description

The rise and fall of a semidiurnal tide, from a plain running minute count.

Function Documentation

int32_t phase ( int32_t minutes )

static

Where in the cycle a minute count lands.

C truncates a negative division towards zero, which leaves a negative remainder, so this pulls it back up by hand.

Parameters

minutes A running minute count, on the same base as tide_level.