al_fixtan man page

al_fixtan — Allegro 5 API


#include <allegro5/allegro.h>

al_fixed al_fixtan(al_fixed x);


This function finds the tangent of a value using a lookup table. The input value must be a fixed point binary angle.


al_fixed angle, res_a, res_b;
float dif;

angle = al_itofix(37);
/* Prove that tan(angle) == sin(angle) / cos(angle). */
res_a = al_fixdiv(al_fixsin(angle), al_fixcos(angle));
res_b = al_fixtan(angle);
dif = al_fixtof(al_fixsub(res_a, res_b));
printf("Precision error: %f\n", dif);

Return Value

Returns the tangent of a fixed point binary format angle as a fixed point value.


Allegro reference manual