DragonFly On-Line Manual Pages

al_fixtan(3)                                                      al_fixtan(3)

NAME
       al_fixtan - Allegro 5 API

SYNOPSIS

              #include <allegro5/allegro.h>

              al_fixed al_fixtan(al_fixed x);

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

       Example:

                  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.  The return
       value will be in radians.

Allegro reference manual                                          al_fixtan(3)