Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
al_fixatan2(3)		   Library Functions Manual		al_fixatan2(3)

NAME
       al_fixatan2 - Allegro 5 API

SYNOPSIS
	      #include <allegro5/allegro.h>

	      al_fixed al_fixatan2(al_fixed y, al_fixed	x)

DESCRIPTION
       This is a fixed point version of	the libc atan2() routine.  It computes
       the  arc	 tangent of y /	x, but the signs of both arguments are used to
       determine the quadrant of the result, and x is permitted	 to  be	 zero.
       This function is	useful to convert Cartesian coordinates	to polar coor-
       dinates.

       Example:

	      al_fixed result;

	      /* Sets `result' to binary angle 64. */
	      result = al_fixatan2(al_itofix(1), 0);

	      /* Sets `result' to binary angle -109. */
	      result = al_fixatan2(al_itofix(-1), al_itofix(-2));

	      /* Fails the assert. */
	      result = al_fixatan2(0, 0);
	      assert(!al_get_errno());

RETURN VALUE
       Returns	the  arc  tangent of y / x in fixed point binary format	angle,
       from -128 to 128.  If both x and	y are zero, returns zero and sets  Al-
       legro's errno to	EDOM.

Allegro	reference manual					al_fixatan2(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=al_fixatan2&sektion=3&manpath=FreeBSD+Ports+14.3.quarterly>

home | help