fixasin(3)                      Allegro manual                      fixasin(3)



NAME
       fixasin - Fixed point inverse sine lookup table. Allegro game
       programming library.

SYNOPSIS
       #include <allegro.h>


       fixed fixasin(fixed x);

DESCRIPTION
       This function finds the inverse sine of a value using a lookup table.
       The input value must be a fixed point value. The inverse sine is
       defined only in the domain from `-1' to `1'. Outside of this input
       range, the function will set `errno' to EDOM and return zero. Example:

          float angle;
          fixed val;

          /* Sets `val' to a right binary angle (`64'). */
          val = fixasin(itofix(1));
          /* Sets `angle' to 0.2405. */
          angle = fixtof(fixmul(fixasin(ftofix(0.238)), fixtorad_r));
          /* This will trigger the assert. */
          val = fixasin(ftofix(-1.09));
          ASSERT(!errno);

RETURN VALUE
       Returns the inverse sine of a fixed point value, measured as fixed
       point binary format angle, or zero if the input was out of the range.
       All return values of this function will be in the range `-64' to `64'.


SEE ALSO
Allegro                          version 4.2.3                      fixasin(3)
