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al_fixatan2(3alleg5) Allegro reference manual() | al_fixatan2(3alleg5) Allegro reference manual() |
NAME¶
al_fixatan2 - Allegro 5 APISYNOPSIS¶
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#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 coordinates.Example:
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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());